DateTimeParse.cs source code in C# .NET

Source code for the .NET framework in C#

                        

Code:

/ FX-1434 / FX-1434 / 1.0 / untmp / whidbey / REDBITS / ndp / clr / src / BCL / System / Globalization / DateTimeParse.cs / 4 / DateTimeParse.cs

                            // ==++== 
//
//   Copyright (c) Microsoft Corporation.  All rights reserved.
//
// ==--== 
////////////////////////////////////////////////////////////////////////////
// 
//  Class:    DateTimeParse 
//
//  Purpose:  This class is called by DateTime to parse a date/time string. 
//
////////////////////////////////////////////////////////////////////////////

namespace System { 
    using System;
    using System.Text; 
    using System.Globalization; 
    using System.Threading;
    using System.Collections; 
    /* SSS_WARNINGS_OFF */
    ////////////////////////////////////////////////////////////////////////
    /*
 
     There are some nasty cases in the parsing of date/time:
 
     0x438    fo  (country:Faroe Islands, language:Faroese) 
        LOCALE_STIME=[.]
        LOCALE_STIMEFOR=[HH.mm.ss] 
        LOCALE_SDATE=[-]
        LOCALE_SSHORTDATE=[dd-MM-yyyy]
        LOCALE_SLONGDATE=[d. MMMM yyyy]
 
        The time separator is ".", However, it also has a "." in the long date format.
 
     0x437: (country:Georgia, language:Georgian) 
        Short date: dd.MM.yy
        Long date:  yyyy ???? dd MM, dddd 

        The order in long date is YDM, which is different from the common ones: YMD/MDY/DMY.

     0x0404: (country:Taiwan, language:Chinese) 
        LOCALE_STIMEFORMAT=[tt hh:mm:ss]
 
        When general date is used, the pattern is "yyyy/M/d tt hh:mm:ss". Note that the "tt" is after "yyyy/M/d". 
        And this is different from most cultures.
 
     0x0437: (country:Georgia, language:Georgian)
        Short date: dd.MM.yy
        Long date:  yyyy ???? dd MM, dddd
 
     0x0456:
 
     */ /* SSS_WARNINGS_ON */ 
    //This class contains only static members
 
    internal static
    class DateTimeParse {

        internal const Int32 MaxDateTimeNumberDigits = 8; 

        internal delegate bool MatchNumberDelegate(ref __DTString str, int digitLen, out int result); 
 
        internal static MatchNumberDelegate m_hebrewNumberParser = new MatchNumberDelegate(DateTimeParse.MatchHebrewDigits);
 
        internal static DateTime ParseExact(String s, String format, DateTimeFormatInfo dtfi, DateTimeStyles style) {
            DateTimeResult result = new DateTimeResult();       // The buffer to store the parsing result.
            result.Init();
            if (TryParseExact(s, format, dtfi, style, ref result)) { 
                return result.parsedDate;
            } 
            else { 
                throw GetDateTimeParseException(ref result);
            } 
        }

        internal static DateTime ParseExact(String s, String format, DateTimeFormatInfo dtfi, DateTimeStyles style, out TimeSpan offset) {
            DateTimeResult result = new DateTimeResult();       // The buffer to store the parsing result. 
            offset = TimeSpan.Zero;
            result.Init(); 
            result.flags |= ParseFlags.CaptureOffset; 
            if (TryParseExact(s, format, dtfi, style, ref result)) {
                offset = result.timeZoneOffset; 
                return result.parsedDate;
            }
            else {
                throw GetDateTimeParseException(ref result); 
            }
        } 
 
        internal static bool TryParseExact(String s, String format, DateTimeFormatInfo dtfi, DateTimeStyles style, out DateTime result) {
            result = DateTime.MinValue; 
            DateTimeResult resultData = new DateTimeResult();       // The buffer to store the parsing result.
            resultData.Init();
            if (TryParseExact(s, format, dtfi, style, ref resultData)) {
                result = resultData.parsedDate; 
                return true;
            } 
            return false; 
        }
 
        internal static bool TryParseExact(String s, String format, DateTimeFormatInfo dtfi, DateTimeStyles style, out DateTime result, out TimeSpan offset) {
            result = DateTime.MinValue;
            offset = TimeSpan.Zero;
            DateTimeResult resultData = new DateTimeResult();       // The buffer to store the parsing result. 
            resultData.Init();
            resultData.flags |= ParseFlags.CaptureOffset; 
            if (TryParseExact(s, format, dtfi, style, ref resultData)) { 
                result = resultData.parsedDate;
                offset = resultData.timeZoneOffset; 
                return true;
            }
            return false;
        } 

        internal static bool TryParseExact(String s, String format, DateTimeFormatInfo dtfi, DateTimeStyles style, ref DateTimeResult result) { 
            if (s == null) { 
                result.SetFailure(ParseFailureKind.ArgumentNull, "ArgumentNull_String", null, "s");
                return false; 
            }
            if (format == null) {
                result.SetFailure(ParseFailureKind.ArgumentNull, "ArgumentNull_String", null, "format");
                return false; 
            }
            if (s.Length == 0) { 
                result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null); 
                return false;
            } 

            if (format.Length == 0) {
                result.SetFailure(ParseFailureKind.Format, "Format_BadFormatSpecifier", null);
                return false; 
            }
 
            BCLDebug.Assert(dtfi != null, "dtfi == null"); 

            return DoStrictParse(s, format, style, dtfi, ref result); 
        }

        internal static DateTime ParseExactMultiple(String s, String[] formats,
                                                DateTimeFormatInfo dtfi, DateTimeStyles style) { 
            DateTimeResult result = new DateTimeResult();       // The buffer to store the parsing result.
            result.Init(); 
            if (TryParseExactMultiple(s, formats, dtfi, style, ref result)) { 
                return result.parsedDate;
            } 
            else {
                throw GetDateTimeParseException(ref result);
            }
        } 

        internal static DateTime ParseExactMultiple(String s, String[] formats, 
                                                DateTimeFormatInfo dtfi, DateTimeStyles style, out TimeSpan offset) { 
            DateTimeResult result = new DateTimeResult();       // The buffer to store the parsing result.
            offset = TimeSpan.Zero; 
            result.Init();
            result.flags |= ParseFlags.CaptureOffset;
            if (TryParseExactMultiple(s, formats, dtfi, style, ref result)) {
                offset = result.timeZoneOffset; 
                return result.parsedDate;
            } 
            else { 
                throw GetDateTimeParseException(ref result);
            } 
        }

        internal static bool TryParseExactMultiple(String s, String[] formats,
                                                   DateTimeFormatInfo dtfi, DateTimeStyles style, out DateTime result, out TimeSpan offset) { 
            result = DateTime.MinValue;
            offset = TimeSpan.Zero; 
            DateTimeResult resultData = new DateTimeResult();       // The buffer to store the parsing result. 
            resultData.Init();
            resultData.flags |= ParseFlags.CaptureOffset; 
            if (TryParseExactMultiple(s, formats, dtfi, style, ref resultData)) {
                result = resultData.parsedDate;
                offset = resultData.timeZoneOffset;
                return true; 
            }
            return false; 
        } 

        internal static bool TryParseExactMultiple(String s, String[] formats, 
                                                   DateTimeFormatInfo dtfi, DateTimeStyles style, out DateTime result) {
            result = DateTime.MinValue;
            DateTimeResult resultData = new DateTimeResult();       // The buffer to store the parsing result.
            resultData.Init(); 
            if (TryParseExactMultiple(s, formats, dtfi, style, ref resultData)) {
                result = resultData.parsedDate; 
                return true; 
            }
            return false; 
        }

        internal static bool TryParseExactMultiple(String s, String[] formats,
                                                DateTimeFormatInfo dtfi, DateTimeStyles style, ref DateTimeResult result) { 
            if (s == null) {
                result.SetFailure(ParseFailureKind.ArgumentNull, "ArgumentNull_String", null, "s"); 
                return false; 
            }
            if (formats == null) { 
                result.SetFailure(ParseFailureKind.ArgumentNull, "ArgumentNull_String", null, "formats");
                return false;
            }
 
            if (s.Length == 0) {
                result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null); 
                return false; 
            }
 
            if (formats.Length == 0) {
                result.SetFailure(ParseFailureKind.Format, "Format_BadFormatSpecifier", null);
                return false;
            } 

            BCLDebug.Assert(dtfi != null, "dtfi == null"); 
 
            //
            // Do a loop through the provided formats and see if we can parse succesfully in 
            // one of the formats.
            //
            for (int i = 0; i < formats.Length; i++) {
                if (formats[i] == null || formats[i].Length == 0) { 
                    result.SetFailure(ParseFailureKind.Format, "Format_BadFormatSpecifier", null);
                    return false; 
                } 
                // Create a new result each time to ensure the runs are independent. Carry through
                // flags from the caller and return the result. 
                DateTimeResult innerResult = new DateTimeResult();       // The buffer to store the parsing result.
                innerResult.Init();
                innerResult.flags = result.flags;
                if (TryParseExact(s, formats[i], dtfi, style, ref innerResult)) { 
                    result.parsedDate = innerResult.parsedDate;
                    result.timeZoneOffset = innerResult.timeZoneOffset; 
                    return (true); 
                }
            } 
            result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null);
            return (false);
        }
 
        ////////////////////////////////////////////////////////////////////////////
        // Date Token Types 
        // 
        // Following is the set of tokens that can be generated from a date
        // string. Notice that the legal set of trailing separators have been 
        // folded in with the date number, and month name tokens. This set
        // of tokens is chosen to reduce the number of date parse states.
        //
        //////////////////////////////////////////////////////////////////////////// 

        internal enum DTT: int { 
 
            End               = 0,    // '\0'
            NumEnd            = 1,    // Num[ ]*[\0] 
            NumAmpm           = 2,    // Num[ ]+AmPm
            NumSpace          = 3,    // Num[ ]+^[Dsep|Tsep|'0\']
            NumDatesep        = 4,    // Num[ ]*Dsep
            NumTimesep        = 5,    // Num[ ]*Tsep 
            MonthEnd          = 6,    // Month[ ]*'\0'
            MonthSpace        = 7,    // Month[ ]+^[Dsep|Tsep|'\0'] 
            MonthDatesep      = 8,    // Month[ ]*Dsep 
            NumDatesuff       = 9,    // Month[ ]*DSuff
            NumTimesuff       = 10,   // Month[ ]*TSuff 
            DayOfWeek         = 11,   // Day of week name
            YearSpace         = 12,   // Year+^[Dsep|Tsep|'0\']
            YearDateSep       = 13,  // Year+Dsep
            YearEnd           = 14,  // Year+['\0'] 
            TimeZone          = 15,  // timezone name
            Era               = 16,  // era name 
            NumUTCTimeMark    = 17,      // Num + 'Z' 
            // When you add a new token which will be in the
            // state table, add it after NumLocalTimeMark. 
            Unk               = 18,   // unknown
            NumLocalTimeMark  = 19,    // Num + 'T'
            Max               = 20,   // marker
        } 

        internal enum TM { 
            NotSet  = -1, 
            AM      = 0,
            PM      = 1, 
        }


        //////////////////////////////////////////////////////////////////////////// 
        //
        // DateTime parsing state enumeration (DS.*) 
        // 
        ////////////////////////////////////////////////////////////////////////////
 
        internal enum DS {
            BEGIN   = 0,
            N       = 1,        // have one number
            NN      = 2,        // have two numbers 

        // The following are known to be part of a date 
 
            D_Nd    = 3,        // date string: have number followed by date separator
            D_NN    = 4,        // date string: have two numbers 
            D_NNd   = 5,        // date string: have two numbers followed by date separator

            D_M     = 6,        // date string: have a month
            D_MN    = 7,        // date string: have a month and a number 
            D_NM    = 8,        // date string: have a number and a month
            D_MNd   = 9,        // date string: have a month and number followed by date separator 
            D_NDS   = 10,       // date string: have one number followed a date suffix. 

            D_Y     = 11,        // date string: have a year. 
            D_YN    = 12,        // date string: have a year and a number
            D_YNd   = 13,        // date string: have a year and a number and a date separator
            D_YM    = 14,        // date string: have a year and a month
            D_YMd   = 15,        // date string: have a year and a month and a date separator 
            D_S     = 16,       // have numbers followed by a date suffix.
            T_S     = 17,       // have numbers followed by a time suffix. 
 
        // The following are known to be part of a time
 
            T_Nt    = 18,          // have num followed by time separator
            T_NNt   = 19,       // have two numbers followed by time separator

 
            ERROR   = 20,
 
        // The following are terminal states. These all have an action 
        // associated with them; and transition back to BEGIN.
 
            DX_NN   = 21,       // day from two numbers
            DX_NNN  = 22,       // day from three numbers
            DX_MN   = 23,       // day from month and one number
            DX_NM   = 24,       // day from month and one number 
            DX_MNN  = 25,       // day from month and two numbers
            DX_DS   = 26,       // a set of date suffixed numbers. 
            DX_DSN  = 27,       // day from date suffixes and one number. 
            DX_NDS  = 28,       // day from one number and date suffixes .
            DX_NNDS = 29,       // day from one number and date suffixes . 

            DX_YNN  = 30,       // date string: have a year and two number
            DX_YMN  = 31,       // date string: have a year, a month, and a number.
            DX_YN   = 32,       // date string: have a year and one number 
            DX_YM   = 33,       // date string: have a year, a month.
            TX_N    = 34,       // time from one number (must have ampm) 
            TX_NN   = 35,       // time from two numbers 
            TX_NNN  = 36,       // time from three numbers
            TX_TS   = 37,       // a set of time suffixed numbers. 
            DX_NNY  = 38,
        }

        //////////////////////////////////////////////////////////////////////////// 
        //
        // NOTE: The following state machine table is dependent on the order of the 
        // DS and DTT enumerations. 
        //
        // For each non terminal state, the following table defines the next state 
        // for each given date token type.
        //
        ////////////////////////////////////////////////////////////////////////////
 
//          End       NumEnd      NumAmPm     NumSpace    NumDaySep   NumTimesep  MonthEnd    MonthSpace  MonthDSep   NumDateSuff NumTimeSuff     DayOfWeek     YearSpace   YearDateSep YearEnd     TimeZone   Era         UTCTimeMark
private static DS[][] dateParsingStates = { 
// DS.BEGIN                                                                             // DS.BEGIN 
new DS[] { DS.BEGIN, DS.ERROR,   DS.TX_N,    DS.N,       DS.D_Nd,    DS.T_Nt,    DS.ERROR,   DS.D_M,     DS.D_M,     DS.D_S,     DS.T_S,         DS.BEGIN,     DS.D_Y,     DS.D_Y,     DS.ERROR,   DS.BEGIN,  DS.BEGIN,    DS.ERROR},
 
// DS.N                                                                                 // DS.N
new DS[] { DS.ERROR, DS.DX_NN,   DS.ERROR,   DS.NN,      DS.D_NNd,   DS.ERROR,   DS.DX_NM,   DS.D_NM,    DS.D_MNd,   DS.D_NDS,   DS.ERROR,       DS.N,         DS.D_YN,    DS.D_YNd,   DS.DX_YN,   DS.N,      DS.N,        DS.ERROR},

// DS.NN                                                                                // DS.NN 
new DS[] { DS.DX_NN, DS.DX_NNN,  DS.TX_N,    DS.DX_NNN,  DS.ERROR,   DS.T_Nt,    DS.DX_MNN,  DS.DX_MNN,  DS.ERROR,   DS.ERROR,   DS.T_S,         DS.NN,        DS.DX_NNY,  DS.ERROR,   DS.DX_NNY,  DS.NN,     DS.NN,       DS.ERROR},
 
// DS.D_Nd                                                                              // DS.D_Nd 
new DS[] { DS.ERROR, DS.DX_NN,   DS.ERROR,   DS.D_NN,    DS.D_NNd,   DS.ERROR,   DS.DX_NM,   DS.D_MN,    DS.D_MNd,   DS.ERROR,   DS.ERROR,       DS.D_Nd,      DS.D_YN,    DS.D_YNd,   DS.DX_YN,   DS.ERROR,  DS.D_Nd,     DS.ERROR},
 
// DS.D_NN                                                                              // DS.D_NN
new DS[] { DS.DX_NN, DS.DX_NNN,  DS.TX_N,    DS.DX_NNN,  DS.ERROR,   DS.T_Nt,    DS.DX_MNN,  DS.DX_MNN,  DS.ERROR,   DS.DX_DS,   DS.T_S,         DS.D_NN,     DS.DX_NNY,   DS.ERROR,   DS.DX_NNY,  DS.ERROR,  DS.D_NN,     DS.ERROR},

// DS.D_NNd                                                                             // DS.D_NNd 
new DS[] { DS.ERROR, DS.DX_NNN,  DS.DX_NNN,  DS.DX_NNN,  DS.ERROR,   DS.ERROR,   DS.DX_MNN,  DS.DX_MNN,  DS.ERROR,   DS.DX_DS,   DS.ERROR,       DS.D_NNd,     DS.DX_NNY,  DS.ERROR,   DS.DX_NNY,  DS.ERROR,  DS.D_NNd,    DS.ERROR},
 
// DS.D_M                                                                               // DS.D_M 
new DS[] { DS.ERROR, DS.DX_MN,   DS.ERROR,   DS.D_MN,    DS.D_MNd,   DS.ERROR,   DS.ERROR,   DS.ERROR,   DS.ERROR,   DS.ERROR,   DS.ERROR,       DS.D_M,       DS.D_YM,    DS.D_YMd,   DS.DX_YM,   DS.ERROR,  DS.D_M,      DS.ERROR},
 
// DS.D_MN                                                                              // DS.D_MN
new DS[] { DS.DX_MN, DS.DX_MNN,  DS.DX_MNN,  DS.DX_MNN,  DS.ERROR,   DS.T_Nt,    DS.ERROR,   DS.ERROR,   DS.ERROR,   DS.DX_DS,   DS.T_S,         DS.D_MN,      DS.DX_YMN,  DS.ERROR,   DS.DX_YMN,  DS.ERROR,  DS.D_MN,     DS.ERROR},

// DS.D_NM                                                                              // DS.D_NM 
new DS[] { DS.DX_NM, DS.DX_MNN,  DS.DX_MNN,  DS.DX_MNN,  DS.ERROR,   DS.T_Nt,    DS.ERROR,   DS.ERROR,   DS.ERROR,   DS.DX_DS,   DS.T_S,         DS.D_NM,      DS.DX_YMN,  DS.ERROR,   DS.DX_YMN,  DS.ERROR,   DS.D_NM,    DS.ERROR},
 
// DS.D_MNd                                                                             // DS.D_MNd 
new DS[] { DS.ERROR, DS.DX_MNN,  DS.ERROR,   DS.DX_MNN,  DS.ERROR,   DS.ERROR,   DS.ERROR,   DS.ERROR,   DS.ERROR,   DS.ERROR,   DS.ERROR,       DS.D_MNd,     DS.DX_YMN,  DS.ERROR,   DS.DX_YMN,  DS.ERROR,   DS.D_MNd,   DS.ERROR},
 
// DS.D_NDS,                                                                            // DS.D_NDS,
new DS[] { DS.DX_NDS,DS.DX_NNDS, DS.DX_NNDS, DS.DX_NNDS, DS.ERROR,   DS.T_Nt,    DS.ERROR,   DS.ERROR,   DS.ERROR,   DS.D_NDS,   DS.T_S,         DS.D_NDS,     DS.ERROR,   DS.ERROR,   DS.ERROR,   DS.ERROR,   DS.D_NDS,   DS.ERROR},

// DS.D_Y                                                                               // DS.D_Y 
new DS[] { DS.ERROR, DS.DX_YN,   DS.ERROR,   DS.D_YN,    DS.D_YNd,   DS.ERROR,   DS.DX_YM,   DS.D_YM,    DS.D_YMd,   DS.D_YM,    DS.ERROR,       DS.D_Y,       DS.ERROR,   DS.ERROR,   DS.ERROR,   DS.ERROR,   DS.D_Y,     DS.ERROR},
 
// DS.D_YN                                                                              // DS.D_YN 
new DS[] { DS.DX_YN, DS.DX_YNN,  DS.DX_YNN,  DS.DX_YNN,  DS.ERROR,   DS.ERROR,   DS.DX_YMN,  DS.DX_YMN,  DS.ERROR,   DS.ERROR,   DS.ERROR,       DS.D_YN,      DS.ERROR,   DS.ERROR,   DS.ERROR,   DS.ERROR,   DS.D_YN,    DS.ERROR},
 
// DS.D_YNd                                                                             // DS.D_YNd
new DS[] { DS.ERROR, DS.DX_YNN,  DS.DX_YNN,  DS.DX_YNN,  DS.ERROR,   DS.ERROR,   DS.DX_YMN,  DS.DX_YMN,  DS.ERROR,   DS.ERROR,   DS.ERROR,       DS.D_YN,      DS.ERROR,   DS.ERROR,   DS.ERROR,   DS.ERROR,   DS.D_YN,    DS.ERROR},

// DS.D_YM                                                                              // DS.D_YM 
new DS[] { DS.DX_YM, DS.DX_YMN,  DS.DX_YMN,  DS.DX_YMN,  DS.ERROR,   DS.ERROR,   DS.ERROR,   DS.ERROR,   DS.ERROR,   DS.ERROR,   DS.ERROR,       DS.D_YM,      DS.ERROR,   DS.ERROR,   DS.ERROR,   DS.ERROR,   DS.D_YM,    DS.ERROR},
 
// DS.D_YMd                                                                             // DS.D_YMd 
new DS[] { DS.ERROR, DS.DX_YMN,  DS.DX_YMN,  DS.DX_YMN,  DS.ERROR,   DS.ERROR,   DS.ERROR,   DS.ERROR,   DS.ERROR,   DS.ERROR,   DS.ERROR,       DS.D_YM,      DS.ERROR,   DS.ERROR,   DS.ERROR,   DS.ERROR,   DS.D_YM,    DS.ERROR},
 
// DS.D_S                                                                               // DS.D_S
new DS[] { DS.DX_DS, DS.DX_DSN,  DS.TX_N,    DS.T_Nt,    DS.ERROR,   DS.T_Nt,    DS.ERROR,   DS.ERROR,   DS.ERROR,   DS.D_S,     DS.T_S,         DS.D_S,       DS.ERROR,   DS.ERROR,   DS.ERROR,   DS.ERROR,   DS.D_S,     DS.ERROR},

// DS.T_S                                                                               // DS.T_S 
new DS[] { DS.TX_TS, DS.TX_TS,   DS.TX_TS,   DS.T_Nt,    DS.D_Nd,    DS.ERROR,   DS.ERROR,   DS.ERROR,   DS.ERROR,   DS.D_S,     DS.T_S,         DS.T_S,       DS.ERROR,   DS.ERROR,   DS.ERROR,   DS.T_S,     DS.T_S,     DS.ERROR},
 
// DS.T_Nt                                                                              // DS.T_Nt 
new DS[] { DS.ERROR, DS.TX_NN,   DS.TX_NN,   DS.TX_NN,   DS.ERROR,   DS.T_NNt,   DS.DX_NM,   DS.D_NM,    DS.ERROR,   DS.ERROR,   DS.T_S,         DS.ERROR,     DS.ERROR,   DS.ERROR,   DS.ERROR,   DS.T_Nt,    DS.T_Nt,    DS.TX_NN},
 
// DS.T_NNt                                                                             // DS.T_NNt
new DS[] { DS.ERROR, DS.TX_NNN,  DS.TX_NNN,  DS.TX_NNN,  DS.ERROR,   DS.ERROR,   DS.ERROR,   DS.ERROR,   DS.ERROR,   DS.ERROR,   DS.T_S,         DS.T_NNt,     DS.ERROR,   DS.ERROR,   DS.ERROR,   DS.T_NNt,   DS.T_NNt,   DS.TX_NNN},

}; 
//          End       NumEnd      NumAmPm     NumSpace    NumDaySep   NumTimesep  MonthEnd    MonthSpace  MonthDSep   NumDateSuff NumTimeSuff     DayOfWeek     YearSpace   YearDateSep YearEnd     TimeZone    Era        UTCMark
 
        internal const String GMTName = "GMT"; 
        internal const String ZuluName = "Z";
 
        //
        // Search from the index of str at str.Index to see if the target string exists in the str.
        //
        private static bool MatchWord(ref __DTString str, String target) 
        {
            int length = target.Length; 
            if (length > (str.Value.Length - str.Index)) { 
                return false;
            } 

            if (str.CompareInfo.Compare(str.Value, str.Index, length,
                                        target, 0, length, CompareOptions.IgnoreCase)!=0) {
                return (false); 
            }
 
            int nextCharIndex = str.Index + target.Length; 

            if (nextCharIndex < str.Value.Length) { 
                char nextCh = str.Value[nextCharIndex];
                if (Char.IsLetter(nextCh)) {
                    return (false);
                } 
            }
            str.Index = nextCharIndex; 
            if (str.Index < str.len) { 
                str.m_current = str.Value[str.Index];
            } 

            return (true);
        }
 

        // 
        // Check the word at the current index to see if it matches GMT name or Zulu name. 
        //
        private static bool GetTimeZoneName(ref __DTString str) 
        {
            //
            // <
 
            if (MatchWord(ref str, GMTName)) {
                return (true); 
            } 

            if (MatchWord(ref str, ZuluName)) { 
                return (true);
            }

            return (false); 
        }
 
        internal static bool IsDigit(char ch) { 
            return (ch >= '0' && ch <= '9');
        } 


        /*=================================ParseFraction==========================
        **Action: Starting at the str.Index, which should be a decimal symbol. 
        ** if the current character is a digit, parse the remaining
        **      numbers as fraction.  For example, if the sub-string starting at str.Index is "123", then 
        **      the method will return 0.123 
        **Returns:      The fraction number.
        **Arguments: 
        **      str the parsing string
        **Exceptions:
        ============================================================================*/
 
        private static bool ParseFraction(ref __DTString str, out double result) {
            result = 0; 
            double decimalBase = 0.1; 
            int digits = 0;
            char ch; 
            while (str.GetNext()
                   && IsDigit(ch = str.m_current)) {
                result += (ch - '0') * decimalBase;
                decimalBase *= 0.1; 
                digits++;
            } 
            return (digits > 0); 
        }
 
        /*=================================ParseTimeZone==========================
        **Action: Parse the timezone offset in the following format:
        **          "+8", "+08", "+0800", "+0800"
        **        This method is used by DateTime.Parse(). 
        **Returns:      The TimeZone offset.
        **Arguments: 
        **      str the parsing string 
        **Exceptions:
        **      FormatException if invalid timezone format is found. 
        ============================================================================*/

        private static bool ParseTimeZone(ref __DTString str, ref TimeSpan result) {
            // The hour/minute offset for timezone. 
            int hourOffset = 0;
            int minuteOffset = 0; 
            DTSubString sub; 

            // Consume the +/- character that has already been read 
            sub = str.GetSubString();
            if (sub.length != 1) {
                return false;
            } 
            char offsetChar = sub[0];
            if (offsetChar != '+' && offsetChar != '-') { 
                return false; 
            }
            str.ConsumeSubString(sub); 

            sub = str.GetSubString();
            if (sub.type != DTSubStringType.Number) {
                return false; 
            }
            int value = sub.value; 
            int length = sub.length; 
            if (length == 1 || length == 2) {
                // Parsing "+8" or "+08" 
                hourOffset = value;
                str.ConsumeSubString(sub);
                // See if we have minutes
                sub = str.GetSubString(); 
                if (sub.length == 1 && sub[0] == ':') {
                    // Parsing "+8:00" or "+08:00" 
                    str.ConsumeSubString(sub); 
                    sub = str.GetSubString();
                    if (sub.type != DTSubStringType.Number || sub.length < 1 || sub.length > 2) { 
                        return false;
                    }
                    minuteOffset = sub.value;
                    str.ConsumeSubString(sub); 
                }
            } 
            else if (length == 3 || length == 4) { 
                // Parsing "+800" or "+0800"
                hourOffset = value / 100; 
                minuteOffset = value % 100;
                str.ConsumeSubString(sub);
            }
            else { 
                // Wrong number of digits
                return false; 
            } 
            BCLDebug.Assert(hourOffset >= 0 && hourOffset <= 99, "hourOffset >= 0 && hourOffset <= 99");
            BCLDebug.Assert(minuteOffset >= 0 && minuteOffset <= 99, "minuteOffset >= 0 && minuteOffset <= 99"); 
            if (minuteOffset < 0 || minuteOffset >= 60) {
                return false;
            }
 
            result = new TimeSpan(hourOffset, minuteOffset, 0);
            if (offsetChar == '-') { 
                result = result.Negate(); 
            }
            return true; 
        }

        //
        // This is the lexer. Check the character at the current index, and put the found token in dtok and 
        // some raw date/time information in raw.
        // 
        private static Boolean Lex( 
            DS dps, ref __DTString str, ref DateTimeToken dtok, ref DateTimeRawInfo raw, ref DateTimeResult result, ref DateTimeFormatInfo dtfi) {
 
            TokenType tokenType;
            int tokenValue;
            int indexBeforeSeparator;
            char charBeforeSeparator; 

            TokenType sep; 
            dtok.dtt = DTT.Unk;     // Assume the token is unkown. 

            str.GetRegularToken(out tokenType, out tokenValue, dtfi); 

            // Look at the regular token.
            switch (tokenType) {
                case TokenType.NumberToken: 
                case TokenType.YearNumberToken:
                    if (raw.numCount == 3 || tokenValue == -1) { 
                        result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null); 
                        return false;
                    } 
                    //
                    // This is a digit.
                    //
                    // If the previous parsing state is DS.T_NNt (like 12:01), and we got another number, 
                    // so we will have a terminal state DS.TX_NNN (like 12:01:02).
                    // If the previous parsing state is DS.T_Nt (like 12:), and we got another number, 
                    // so we will have a terminal state DS.TX_NN (like 12:01). 
                    //
                    // Look ahead to see if the following character is a decimal point or timezone offset. 
                    // This enables us to parse time in the forms of:
                    //  "11:22:33.1234" or "11:22:33-08".
                    if (dps == DS.T_NNt) {
                        if ((str.Index < str.len - 1)) { 
                            char nextCh = str.Value[str.Index];
                            if (nextCh == '.') { 
                                // While ParseFraction can fail, it just means that there were no digits after 
                                // the dot. In this case ParseFraction just removes the dot. This is actually
                                // valid for cultures like Albanian, that join the time marker to the time with 
                                // with a dot: e.g. "9:03.MD"
                                ParseFraction(ref str, out raw.fraction);
                            }
                        } 
                    }
                    if (dps == DS.T_NNt || dps == DS.T_Nt) { 
                        if ((str.Index < str.len - 1)) { 
                            char nextCh = str.Value[str.Index];
                            // Skip whitespace, but don't update the index unless we find a time zone marker 
                            int whitespaceCount = 0;
                            while (Char.IsWhiteSpace(nextCh) && str.Index + whitespaceCount < str.len - 1) {
                                whitespaceCount++;
                                nextCh = str.Value[str.Index + whitespaceCount]; 
                            }
                            if (nextCh == '+' || nextCh == '-') { 
                                str.Index += whitespaceCount; 
                                if ((result.flags & ParseFlags.TimeZoneUsed) != 0) {
                                    // Should not have two timezone offsets. 
                                    result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null);
                                    return false;
                                }
                                result.flags |= ParseFlags.TimeZoneUsed; 
                                if (!ParseTimeZone(ref str, ref result.timeZoneOffset)) {
                                    result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null); 
                                    return false; 
                                }
                            } 
                        }
                    }

                    dtok.num = tokenValue; 
                    if (tokenType == TokenType.YearNumberToken)
                    { 
                        if (raw.year == -1) 
                        {
                            raw.year = tokenValue; 
                            //
                            // If we have number which has 3 or more digits (like "001" or "0001"),
                            // we assume this number is a year. Save the currnet raw.numCount in
                            // raw.year. 
                            //
                            switch (sep = str.GetSeparatorToken(dtfi, out indexBeforeSeparator, out charBeforeSeparator)) { 
                                case TokenType.SEP_End: 
                                    dtok.dtt     = DTT.YearEnd;
                                    break; 
                                case TokenType.SEP_Am:
                                case TokenType.SEP_Pm:
                                    if (raw.timeMark == TM.NotSet) {
                                        raw.timeMark = (sep == TokenType.SEP_Am ? TM.AM : TM.PM); 
                                        dtok.dtt    = DTT.YearSpace;
                                    } else { 
                                        result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null); 
                                    }
                                    break; 
                                case TokenType.SEP_Space:
                                    dtok.dtt    = DTT.YearSpace;
                                    break;
                                case TokenType.SEP_Date: 
                                    dtok.dtt     = DTT.YearDateSep;
                                    break; 
                                case TokenType.SEP_DateOrOffset: 
                                    // The separator is either a date separator or the start of a time zone offset. If the token will complete the date then
                                    // process just the number and roll back the index so that the outer loop can attempt to parse the time zone offset. 
                                    if ((dateParsingStates[(int)dps][(int) DTT.YearDateSep] == DS.ERROR)
                                        && (dateParsingStates[(int)dps][(int) DTT.YearSpace] > DS.ERROR)) {
                                        str.Index = indexBeforeSeparator;
                                        str.m_current = charBeforeSeparator; 
                                        dtok.dtt = DTT.YearSpace;
                                    } 
                                    else { 
                                        dtok.dtt = DTT.YearDateSep;
                                    } 
                                    break;
                                case TokenType.SEP_YearSuff:
                                case TokenType.SEP_MonthSuff:
                                case TokenType.SEP_DaySuff: 
                                    dtok.dtt    = DTT.NumDatesuff;
                                    dtok.suffix = sep; 
                                    break; 
                                case TokenType.SEP_HourSuff:
                                case TokenType.SEP_MinuteSuff: 
                                case TokenType.SEP_SecondSuff:
                                    dtok.dtt    = DTT.NumTimesuff;
                                    dtok.suffix = sep;
                                    break; 
                                default:
                                    // Invalid separator after number number. 
                                    result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null); 
                                    return false;
                            } 
                            //
                            // Found the token already. Return now.
                            //
                            return true; 
                        }
                        result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null); 
                        return false; 
                    }
                    switch (sep = str.GetSeparatorToken(dtfi, out indexBeforeSeparator, out charBeforeSeparator)) 
                    {
                        //
                        // Note here we check if the numCount is less than three.
                        // When we have more than three numbers, it will be caught as error in the state machine. 
                        //
                        case TokenType.SEP_End: 
                            dtok.dtt = DTT.NumEnd; 
                            raw.AddNumber(dtok.num);
                            break; 
                        case TokenType.SEP_Am:
                        case TokenType.SEP_Pm:
                            if (raw.timeMark == TM.NotSet) {
                                raw.timeMark = (sep == TokenType.SEP_Am ? TM.AM : TM.PM); 
                                dtok.dtt = DTT.NumAmpm;
                                raw.AddNumber(dtok.num); 
                            } else { 
                                result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null);
                            } 
                            break;
                        case TokenType.SEP_Space:
                            dtok.dtt = DTT.NumSpace;
                            raw.AddNumber(dtok.num); 
                            break;
                        case TokenType.SEP_Date: 
                            dtok.dtt = DTT.NumDatesep; 
                            raw.AddNumber(dtok.num);
                            break; 
                        case TokenType.SEP_DateOrOffset:
                            // The separator is either a date separator or the start of a time zone offset. If the token will complete the date then
                            // process just the number and roll back the index so that the outer loop can attempt to parse the time zone offset.
                            if ((dateParsingStates[(int)dps][(int) DTT.NumDatesep] == DS.ERROR) 
                                && (dateParsingStates[(int)dps][(int) DTT.NumSpace] > DS.ERROR)) {
                                str.Index = indexBeforeSeparator; 
                                str.m_current = charBeforeSeparator; 
                                dtok.dtt = DTT.NumSpace;
                            } 
                            else {
                                dtok.dtt = DTT.NumDatesep;
                            }
                            raw.AddNumber(dtok.num); 
                            break;
                        case TokenType.SEP_Time: 
                            dtok.dtt = DTT.NumTimesep; 
                            raw.AddNumber(dtok.num);
                            break; 
                        case TokenType.SEP_YearSuff:
                            dtok.num = dtfi.Calendar.ToFourDigitYear(tokenValue);
                            dtok.dtt    = DTT.NumDatesuff;
                            dtok.suffix = sep; 
                            break;
                        case TokenType.SEP_MonthSuff: 
                        case TokenType.SEP_DaySuff: 
                            dtok.dtt    = DTT.NumDatesuff;
                            dtok.suffix = sep; 
                            break;
                        case TokenType.SEP_HourSuff:
                        case TokenType.SEP_MinuteSuff:
                        case TokenType.SEP_SecondSuff: 
                            dtok.dtt    = DTT.NumTimesuff;
                            dtok.suffix = sep; 
                            break; 
                        case TokenType.SEP_LocalTimeMark:
                            dtok.dtt = DTT.NumLocalTimeMark; 
                            raw.AddNumber(dtok.num);
                            break;
                        default:
                            // Invalid separator after number number. 
                            result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null);
                            return false; 
                    } 
                    break;
                case TokenType.HebrewNumber: 
                    if (tokenValue >= 100) {
                        // This is a year number
                        if (raw.year == -1) {
                            raw.year = tokenValue; 
                            //
                            // If we have number which has 3 or more digits (like "001" or "0001"), 
                            // we assume this number is a year. Save the currnet raw.numCount in 
                            // raw.year.
                            // 
                            switch (sep = str.GetSeparatorToken(dtfi, out indexBeforeSeparator, out charBeforeSeparator)) {
                                case TokenType.SEP_End:
                                    dtok.dtt = DTT.YearEnd;
                                    break; 
                                case TokenType.SEP_Space:
                                    dtok.dtt = DTT.YearSpace; 
                                    break; 
                                case TokenType.SEP_DateOrOffset:
                                    // The separator is either a date separator or the start of a time zone offset. If the token will complete the date then 
                                    // process just the number and roll back the index so that the outer loop can attempt to parse the time zone offset.
                                    if (dateParsingStates[(int)dps][(int) DTT.YearSpace] > DS.ERROR) {
                                        str.Index = indexBeforeSeparator;
                                        str.m_current = charBeforeSeparator; 
                                        dtok.dtt = DTT.YearSpace;
                                        break; 
                                    } 
                                    goto default;
                                default: 
                                    // Invalid separator after number number.
                                    result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null);
                                    return false;
                            } 
                        } else {
                            // Invalid separator after number number. 
                            result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null); 
                            return false;
                        } 
                    } else {
                        // This is a day number
                        dtok.num = tokenValue;
                        raw.AddNumber(dtok.num); 

                        switch (sep = str.GetSeparatorToken(dtfi, out indexBeforeSeparator, out charBeforeSeparator)) { 
                            // 
                            // Note here we check if the numCount is less than three.
                            // When we have more than three numbers, it will be caught as error in the state machine. 
                            //
                            case TokenType.SEP_End:
                                dtok.dtt = DTT.NumEnd;
                                break; 
                            case TokenType.SEP_Space:
                            case TokenType.SEP_Date: 
                                dtok.dtt = DTT.NumDatesep; 
                                break;
                            case TokenType.SEP_DateOrOffset: 
                                // The separator is either a date separator or the start of a time zone offset. If the token will complete the date then
                                // process just the number and roll back the index so that the outer loop can attempt to parse the time zone offset.
                                if ((dateParsingStates[(int)dps][(int) DTT.NumDatesep] == DS.ERROR)
                                    && (dateParsingStates[(int)dps][(int) DTT.NumSpace] > DS.ERROR)) { 
                                    str.Index = indexBeforeSeparator;
                                    str.m_current = charBeforeSeparator; 
                                    dtok.dtt = DTT.NumSpace; 
                                }
                                else { 
                                    dtok.dtt = DTT.NumDatesep;
                                }
                                break;
                            default: 
                                // Invalid separator after number number.
                                result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null); 
                                return false; 
                        }
                    } 
                    break;
                case TokenType.DayOfWeekToken:
                    if (raw.dayOfWeek == -1)
                    { 
                        //
                        // This is a day of week name. 
                        // 
                        raw.dayOfWeek = tokenValue;
                        dtok.dtt = DTT.DayOfWeek; 
                    } else {
                        result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null);
                        return false;
                    } 
                    break;
                case TokenType.MonthToken: 
                    if (raw.month == -1) 
                    {
                        // 
                        // This is a month name
                        //
                        switch(sep=str.GetSeparatorToken(dtfi, out indexBeforeSeparator, out charBeforeSeparator))
                        { 
                            case TokenType.SEP_End:
                                dtok.dtt = DTT.MonthEnd; 
                                break; 
                            case TokenType.SEP_Space:
                                dtok.dtt = DTT.MonthSpace; 
                                break;
                            case TokenType.SEP_Date:
                                dtok.dtt = DTT.MonthDatesep;
                                break; 
                            case TokenType.SEP_DateOrOffset:
                                // The separator is either a date separator or the start of a time zone offset. If the token will complete the date then 
                                // process just the number and roll back the index so that the outer loop can attempt to parse the time zone offset. 
                                if ((dateParsingStates[(int)dps][(int) DTT.MonthDatesep] == DS.ERROR)
                                    && (dateParsingStates[(int)dps][(int) DTT.MonthSpace] > DS.ERROR)) { 
                                    str.Index = indexBeforeSeparator;
                                    str.m_current = charBeforeSeparator;
                                    dtok.dtt = DTT.MonthSpace;
                                } 
                                else {
                                    dtok.dtt = DTT.MonthDatesep; 
                                } 
                                break;
                            default: 
                                //Invalid separator after month name
                                result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null);
                                return false;
                        } 
                        raw.month = tokenValue;
                    }  else { 
                        result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null); 
                        return false;
                    } 
                    break;
                case TokenType.EraToken:
                    if (result.era != -1) {
                        result.era = tokenValue; 
                        dtok.dtt = DTT.Era;
                    } else { 
                        result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null); 
                        return false;
                    } 
                    break;
                case TokenType.JapaneseEraToken:
                    // Special case for Japanese.  We allow Japanese era name to be used even if the calendar is not Japanese Calendar.
                    result.calendar = JapaneseCalendar.GetDefaultInstance(); 
                    dtfi = DateTimeFormatInfo.GetJapaneseCalendarDTFI();
                    if (result.era != -1) { 
                        result.era = tokenValue; 
                        dtok.dtt = DTT.Era;
                    } else { 
                        result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null);
                        return false;
                    }
                    break; 
                case TokenType.TEraToken:
/* SSS_WARNINGS_OFF */                    // Special case for Taiwan. 
                    result.calendar = TaiwanCalendar.GetDefaultInstance(); 
                    dtfi = DateTimeFormatInfo.GetTaiwanCalendarDTFI(); /* SSS_WARNINGS_ON */
                    if (result.era != -1) { 
                        result.era = tokenValue;
                        dtok.dtt = DTT.Era;
                    } else {
                        result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null); 
                        return false;
                    } 
                    break; 
                case TokenType.TimeZoneToken:
                    // 
                    // This is a timezone designator
                    //
                    // NOTENOTE : for now, we only support "GMT" and "Z" (for Zulu time).
                    // 
                    dtok.dtt = DTT.TimeZone;
                    result.flags |= ParseFlags.TimeZoneUsed; 
                    result.timeZoneOffset = new TimeSpan(0); 
                    result.flags |= ParseFlags.TimeZoneUtc;
                    break; 
                case TokenType.EndOfString:
                    dtok.dtt = DTT.End;
                    break;
                case TokenType.DateWordToken: 
                case TokenType.IgnorableSymbol:
                    // Date words and ignorable symbols can just be skipped over 
                    break; 
                case TokenType.Am:
                case TokenType.Pm: 
                    if (raw.timeMark == TM.NotSet) {
                        raw.timeMark = (TM)tokenValue;
                    } else {
                        result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null); 
                        return false;
                    } 
                    break; 
                case TokenType.UnknownToken:
                    if (Char.IsLetter(str.m_current)) { 
                        result.SetFailure(ParseFailureKind.FormatWithParameter, "Format_UnknowDateTimeWord",  str.Index);
                        return (false);
                    }
                    // If DateTimeParseIgnorePunctuation is defined and we are parsing a DateTime (not a DateTimeOffset), we want to have the V1.1 behavior of just 
                    // ignoring any unrecognized punctuation and moving on to the next character
                    if (Environment.GetCompatibilityFlag(CompatibilityFlag.DateTimeParseIgnorePunctuation) && ((result.flags & ParseFlags.CaptureOffset) == 0)) { 
                        str.GetNext(); 
                        return true;
                    } 
                    else if ((str.m_current == '-' || str.m_current == '+') && ((result.flags & ParseFlags.TimeZoneUsed) == 0)) {
                        Int32 originalIndex = str.Index;
                        if (ParseTimeZone(ref str, ref result.timeZoneOffset)) {
                            result.flags |= ParseFlags.TimeZoneUsed; 
                            return true;
                        } 
                        else { 
                            // Time zone parse attempt failed. Fall through to punctuation handling.
                            str.Index = originalIndex; 
                        }
                    }

                    if (VerifyValidPunctuation(ref str)) { 
                        return true;
                    } 
                    result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null); 
                    return false;
            } 

            return true;
        }
 
        private static Boolean VerifyValidPunctuation(ref __DTString str) {
            // Compatability Behavior. Allow trailing nulls and surrounding hashes 
            Char ch = str.Value[str.Index]; 
            if (ch == '#') {
                bool foundStart = false; 
                bool foundEnd = false;
                for (int i = 0; i < str.len; i++) {
                    ch = str.Value[i];
                    if (ch == '#') { 
                        if (foundStart) {
                            if (foundEnd) { 
                                // Having more than two hashes is invalid 
                                return false;
                            } 
                            else {
                                foundEnd = true;
                            }
                        } 
                        else {
                            foundStart = true; 
                        } 
                    }
                    else if (ch == '\0') { 
                        // Allow nulls only at the end
                        if (!foundEnd) {
                            return false;
                        } 
                    }
                    else if ((!Char.IsWhiteSpace(ch))) { 
                        // Anthyhing other than whitespace outside hashes is invalid 
                        if (!foundStart || foundEnd) {
                            return false; 
                        }
                    }
                }
                if (!foundEnd) { 
                    // The has was un-paired
                    return false; 
                } 
                // Valid Hash usage: eat the hash and continue.
                str.GetNext(); 
                return true;
            }
            else if (ch == '\0') {
                for (int i = str.Index; i < str.len; i++) { 
                    if (str.Value[i] != '\0') {
                        // Nulls are only valid if they are the only trailing character 
                        return false; 
                    }
                } 
                // Move to the end of the string
                str.Index = str.len;
                return true;
            } 
            return false;
        } 
 
        private const int ORDER_YMD = 0;     // The order of date is Year/Month/Day.
        private const int ORDER_MDY = 1;     // The order of date is Month/Day/Year. 
        private const int ORDER_DMY = 2;     // The order of date is Day/Month/Year.
        private const int ORDER_YDM = 3;     // The order of date is Year/Day/Month
        private const int ORDER_YM  = 4;     // Year/Month order.
        private const int ORDER_MY  = 5;     // Month/Year order. 
        private const int ORDER_MD  = 6;     // Month/Day order.
        private const int ORDER_DM  = 7;     // Day/Month order. 
 
        //
        // Decide the year/month/day order from the datePattern. 
        //
        // Return 0 for YMD, 1 for MDY, 2 for DMY, otherwise -1.
        //
        private static Boolean GetYearMonthDayOrder(String datePattern, DateTimeFormatInfo dtfi, out int order) 
        {
            int yearOrder   = -1; 
            int monthOrder  = -1; 
            int dayOrder    = -1;
            int orderCount  =  0; 

            bool inQuote = false;

            for (int i = 0; i < datePattern.Length && orderCount < 3; i++) 
            {
                char ch = datePattern[i]; 
                if (ch == '\'' || ch == '"') 
                {
                    inQuote = !inQuote; 
                }

                if (!inQuote)
                { 
                    if (ch == 'y')
                    { 
                        yearOrder = orderCount++; 

                        // 
                        // Skip all year pattern charaters.
                        //
                        for(; i+1 < datePattern.Length && datePattern[i+1] == 'y'; i++)
                        { 
                            // Do nothing here.
                        } 
                    } 
                    else if (ch == 'M')
                    { 
                        monthOrder = orderCount++;
                        //
                        // Skip all month pattern characters.
                        // 
                        for(; i+1 < datePattern.Length && datePattern[i+1] == 'M'; i++)
                        { 
                            // Do nothing here. 
                        }
                    } 
                    else if (ch == 'd')
                    {

                        int patternCount = 1; 
                        //
                        // Skip all day pattern characters. 
                        // 
                        for(; i+1 < datePattern.Length && datePattern[i+1] == 'd'; i++)
                        { 
                            patternCount++;
                        }
                        //
                        // Make sure this is not "ddd" or "dddd", which means day of week. 
                        //
                        if (patternCount <= 2) 
                        { 
                            dayOrder = orderCount++;
                        } 
                    }
                }
            }
 
            if (yearOrder == 0 && monthOrder == 1 && dayOrder == 2)
            { 
                order = ORDER_YMD; 
                return true;
            } 
            if (monthOrder == 0 && dayOrder == 1 && yearOrder == 2)
            {
                order = ORDER_MDY;
                return true; 
            }
            if (dayOrder == 0 && monthOrder == 1 && yearOrder == 2) 
            { 
                order = ORDER_DMY;
                return true; 
            }
            if (yearOrder == 0 && dayOrder == 1 && monthOrder == 2)
            {
                order = ORDER_YDM; 
                return true;
            } 
            order = -1; 
            return false;
        } 

        //
        // Decide the year/month order from the pattern.
        // 
        // Return 0 for YM, 1 for MY, otherwise -1.
        // 
        private static Boolean GetYearMonthOrder(String pattern, DateTimeFormatInfo dtfi, out int order) 
        {
            int yearOrder   = -1; 
            int monthOrder  = -1;
            int orderCount  =  0;

            bool inQuote = false; 
            for (int i = 0; i < pattern.Length && orderCount < 2; i++)
            { 
                char ch = pattern[i]; 
                if (ch == '\'' || ch == '"')
                { 
                    inQuote = !inQuote;
                }

                if (!inQuote) 
                {
                    if (ch == 'y') 
                    { 
                        yearOrder = orderCount++;
 
                        //
                        // Skip all year pattern charaters.
                        //
                        for(; i+1 < pattern.Length && pattern[i+1] == 'y'; i++) 
                        {
                        } 
                    } 
                    else if (ch == 'M')
                    { 
                        monthOrder = orderCount++;
                        //
                        // Skip all month pattern characters.
                        // 
                        for(; i+1 < pattern.Length && pattern[i+1] == 'M'; i++)
                        { 
                        } 
                    }
                } 
            }

            if (yearOrder == 0 && monthOrder == 1)
            { 
                order = ORDER_YM;
                return true; 
            } 
            if (monthOrder == 0 && yearOrder == 1)
            { 
                order = ORDER_MY;
                return true;
            }
            order = -1; 
            return false;
        } 
 
        //
        // Decide the month/day order from the pattern. 
        //
        // Return 0 for MD, 1 for DM, otherwise -1.
        //
        private static Boolean GetMonthDayOrder(String pattern, DateTimeFormatInfo dtfi, out int order) 
        {
            int monthOrder  = -1; 
            int dayOrder    = -1; 
            int orderCount  =  0;
 
            bool inQuote = false;
            for (int i = 0; i < pattern.Length && orderCount < 2; i++)
            {
                char ch = pattern[i]; 
                if (ch == '\'' || ch == '"')
                { 
                    inQuote = !inQuote; 
                }
 
                if (!inQuote)
                {
                    if (ch == 'd')
                    { 
                        int patternCount = 1;
                        // 
                        // Skip all day pattern charaters. 
                        //
                        for(; i+1 < pattern.Length && pattern[i+1] == 'd'; i++) 
                        {
                            patternCount++;
                        }
 
                        //
                        // Make sure this is not "ddd" or "dddd", which means day of week. 
                        // 
                        if (patternCount <= 2)
                        { 
                            dayOrder = orderCount++;
                        }

                    } 
                    else if (ch == 'M')
                    { 
                        monthOrder = orderCount++; 
                        //
                        // Skip all month pattern characters. 
                        //
                        for(; i+1 < pattern.Length && pattern[i+1] == 'M'; i++)
                        {
                        } 
                    }
                } 
            } 

            if (monthOrder == 0 && dayOrder == 1) 
            {
                order = ORDER_MD;
                return true;
            } 
            if (dayOrder == 0 && monthOrder == 1)
            { 
                order = ORDER_DM; 
                return true;
            } 
            order = -1;
            return false;
        }
 
        //
        // Adjust the two-digit year if necessary. 
        // 
        private static int AdjustYear(ref DateTimeResult result, int year)
        { 
            if (year < 100)
            {
                year = result.calendar.ToFourDigitYear(year);
            } 
            return (year);
        } 
 
        private static bool SetDateYMD(ref DateTimeResult result, int year, int month, int day)
        { 
            // Note, longer term these checks should be done at the end of the parse. This current
            // way of checking creates order dependence with parsing the era name.
            if (result.calendar.IsValidDay(year, month, day, result.era))
            { 
                result.SetDate(year, month, day);                           // YMD
                return (true); 
            } 
            return (false);
        } 

        private static bool SetDateMDY(ref DateTimeResult result, int month, int day, int year)
        {
            return (SetDateYMD(ref result, year, month, day)); 
        }
 
        private static bool SetDateDMY(ref DateTimeResult result, int day, int month, int year) 
        {
            return (SetDateYMD(ref result, year, month, day)); 
        }

        private static bool SetDateYDM(ref DateTimeResult result, int year, int day, int month)
        { 
            return (SetDateYMD(ref result, year, month, day));
        } 
 
        private static void GetDefaultYear(ref DateTimeResult result, ref DateTimeStyles styles) {
            result.Year = result.calendar.GetYear(GetDateTimeNow(ref result, ref styles)); 
            result.flags |= ParseFlags.YearDefault;
        }

        // Processing teriminal case: DS.DX_NN 
        private static Boolean GetDayOfNN(ref DateTimeResult result, ref DateTimeStyles styles, ref DateTimeRawInfo raw, DateTimeFormatInfo dtfi) {
 
            if ((result.flags & ParseFlags.HaveDate) != 0) { 
                // Multiple dates in the input string
                result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null); 
                return false;
            }

            int n1 = raw.GetNumber(0); 
            int n2 = raw.GetNumber(1);
 
            GetDefaultYear(ref result, ref styles); 

            int order; 
            if (!GetMonthDayOrder(dtfi.MonthDayPattern, dtfi, out order)) {
                result.SetFailure(ParseFailureKind.FormatWithParameter, "Format_BadDatePattern", dtfi.MonthDayPattern);
                return false;
            } 

            if (order == ORDER_MD) 
            { 
                if (SetDateYMD(ref result, result.Year, n1, n2))                           // MD
                { 
                    result.flags |= ParseFlags.HaveDate;
                    return true;
                }
            } else { 
                // ORDER_DM
                if (SetDateYMD(ref result, result.Year, n2, n1))                           // DM 
                { 
                    result.flags |= ParseFlags.HaveDate;
                    return true; 
                }
            }
            result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null);
            return false; 
        }
 
        // Processing teriminal case: DS.DX_NNN 
        private static Boolean GetDayOfNNN(ref DateTimeResult result, ref DateTimeRawInfo raw, DateTimeFormatInfo dtfi)
        { 
            if ((result.flags & ParseFlags.HaveDate) != 0) {
                // Multiple dates in the input string
                result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null);
                return false; 
            }
 
            int n1 = raw.GetNumber(0); 
            int n2 = raw.GetNumber(1);;
            int n3 = raw.GetNumber(2); 

            int order;
            if (!GetYearMonthDayOrder(dtfi.ShortDatePattern, dtfi, out order)) {
                result.SetFailure(ParseFailureKind.FormatWithParameter, "Format_BadDatePattern", dtfi.ShortDatePattern); 
                return false;
            } 
 
            if (order == ORDER_YMD) {
                if (SetDateYMD(ref result, AdjustYear(ref result, n1), n2, n3))         // YMD 
                {
                    result.flags |= ParseFlags.HaveDate;
                    return true;
                } 
            } else if (order == ORDER_MDY) {
                if (SetDateMDY(ref result, n1, n2, AdjustYear(ref result, n3)))         // MDY 
                { 
                    result.flags |= ParseFlags.HaveDate;
                    return true; 
                }
            } else if (order == ORDER_DMY) {
                if (SetDateDMY(ref result, n1, n2, AdjustYear(ref result, n3)))         // DMY
                { 
                    result.flags |= ParseFlags.HaveDate;
                    return true; 
                } 
            } else if (order == ORDER_YDM) {
                if (SetDateYDM(ref result, AdjustYear(ref result, n1), n2, n3))         // YDM 
                {
                    result.flags |= ParseFlags.HaveDate;
                    return true;
                } 
            }
            result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null); 
            return false; 
        }
 
        private static Boolean GetDayOfMN(ref DateTimeResult result, ref DateTimeStyles styles, ref DateTimeRawInfo raw, DateTimeFormatInfo dtfi) {

            if ((result.flags & ParseFlags.HaveDate) != 0) {
                // Multiple dates in the input string 
                result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null);
                return false; 
            } 

            // The interpretation is based on the MonthDayPattern and YearMonthPattern 
            //
            //    MonthDayPattern   YearMonthPattern  Interpretation
            //    ---------------   ----------------  ---------------
            //    MMMM dd           MMMM yyyy         Day 
            //    MMMM dd           yyyy MMMM         Day
            //    dd MMMM           MMMM yyyy         Year 
            //    dd MMMM           yyyy MMMM         Day 
            //
            // In the first and last cases, it could be either or neither, but a day is a better default interpretation 
            // than a 2 digit year.

            int monthDayOrder;
            if (!GetMonthDayOrder(dtfi.MonthDayPattern, dtfi, out monthDayOrder)) { 
                result.SetFailure(ParseFailureKind.FormatWithParameter, "Format_BadDatePattern", dtfi.MonthDayPattern);
                return false; 
            } 
            if (monthDayOrder == ORDER_DM) {
                int yearMonthOrder; 
                if (!GetYearMonthOrder(dtfi.YearMonthPattern, dtfi, out yearMonthOrder)) {
                    result.SetFailure(ParseFailureKind.FormatWithParameter, "Format_BadDatePattern", dtfi.YearMonthPattern);
                    return false;
                } 
                if (yearMonthOrder == ORDER_MY) {
                    if (!SetDateYMD(ref result, AdjustYear(ref result, raw.GetNumber(0)), raw.month, 1)) { 
                        result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null); 
                        return false;
                    } 
                    return true;
                }
            }
 
            GetDefaultYear(ref result, ref styles);
            if (!SetDateYMD(ref result, result.Year, raw.month, raw.GetNumber(0))) { 
                result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null); 
                return false;
            } 
            return true;

        }
 
        ////////////////////////////////////////////////////////////////////////
        //  Actions: 
        //  Deal with the terminal state for Hebrew Month/Day pattern 
        //
        //////////////////////////////////////////////////////////////////////// 

        private static Boolean GetHebrewDayOfNM(ref DateTimeResult result, ref DateTimeRawInfo raw, DateTimeFormatInfo dtfi)
        {
            int monthDayOrder; 
            if (!GetMonthDayOrder(dtfi.MonthDayPattern, dtfi, out monthDayOrder)) {
                result.SetFailure(ParseFailureKind.FormatWithParameter, "Format_BadDatePattern", dtfi.MonthDayPattern); 
                return false; 
            }
            result.Month = raw.month; 
            if (monthDayOrder == ORDER_DM)
            {
                if (result.calendar.IsValidDay(result.Year, result.Month, raw.GetNumber(0), result.era))
                { 
                    result.Day  = raw.GetNumber(0);
                    return true; 
                } 
            }
            result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null); 
            return false;
        }

        private static Boolean GetDayOfNM(ref DateTimeResult result, ref DateTimeStyles styles, ref DateTimeRawInfo raw, DateTimeFormatInfo dtfi) 
        {
            if ((result.flags & ParseFlags.HaveDate) != 0) { 
                // Multiple dates in the input string 
                result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null);
                return false; 
            }

            // The interpretation is based on the MonthDayPattern and YearMonthPattern
            // 
            //    MonthDayPattern   YearMonthPattern  Interpretation
            //    ---------------   ----------------  --------------- 
            //    MMMM dd           MMMM yyyy         Day 
            //    MMMM dd           yyyy MMMM         Year
            //    dd MMMM           MMMM yyyy         Day 
            //    dd MMMM           yyyy MMMM         Day
            //
            // In the first and last cases, it could be either or neither, but a day is a better default interpretation
            // than a 2 digit year. 

            int monthDayOrder; 
            if (!GetMonthDayOrder(dtfi.MonthDayPattern, dtfi, out monthDayOrder)) { 
                result.SetFailure(ParseFailureKind.FormatWithParameter, "Format_BadDatePattern", dtfi.MonthDayPattern);
                return false; 
            }
            if (monthDayOrder == ORDER_MD) {
                int yearMonthOrder;
                if (!GetYearMonthOrder(dtfi.YearMonthPattern, dtfi, out yearMonthOrder)) { 
                    result.SetFailure(ParseFailureKind.FormatWithParameter, "Format_BadDatePattern", dtfi.YearMonthPattern);
                    return false; 
                } 
                if (yearMonthOrder == ORDER_YM) {
                    if (!SetDateYMD(ref result, AdjustYear(ref result, raw.GetNumber(0)), raw.month, 1)) { 
                        result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null);
                        return false;
                    }
                    return true; 
                }
            } 
 
            GetDefaultYear(ref result, ref styles);
            if (!SetDateYMD(ref result, result.Year, raw.month, raw.GetNumber(0))) { 
                result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null);
                return false;
            }
            return true; 
        }
 
        private static Boolean GetDayOfMNN(ref DateTimeResult result, ref DateTimeRawInfo raw, DateTimeFormatInfo dtfi) 
        {
            if ((result.flags & ParseFlags.HaveDate) != 0) { 
                // Multiple dates in the input string
                result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null);
                return false;
            } 

            int n1 = raw.GetNumber(0); 
            int n2 = raw.GetNumber(1); 

            int order; 
            if (!GetYearMonthDayOrder(dtfi.ShortDatePattern, dtfi, out order)) {
                result.SetFailure(ParseFailureKind.FormatWithParameter, "Format_BadDatePattern", dtfi.ShortDatePattern);
                return false;
            } 
            int year;
 
            if (order == ORDER_MDY) 
            {
                if (result.calendar.IsValidDay(year = AdjustYear(ref result, n2), raw.month, n1, result.era)) 
                {
                    result.SetDate(year, raw.month, n1);      // MDY
                    result.flags |= ParseFlags.HaveDate;
                    return true; 
                }
                else if (result.calendar.IsValidDay(year = AdjustYear(ref result, n1), raw.month, n2, result.era)) 
                { 
                    result.SetDate(year, raw.month, n2);      // YMD
                    result.flags |= ParseFlags.HaveDate; 
                    return true;
                }
            }
            else if (order == ORDER_YMD) 
            {
                if (result.calendar.IsValidDay(year = AdjustYear(ref result, n1), raw.month, n2, result.era)) 
                { 
                    result.SetDate(year, raw.month, n2);      // YMD
                    result.flags |= ParseFlags.HaveDate; 
                    return true;
                }
                else if (result.calendar.IsValidDay(year = AdjustYear(ref result, n2), raw.month, n1, result.era))
                { 
                    result.SetDate(year, raw.month, n1);      // DMY
                    result.flags |= ParseFlags.HaveDate; 
                    return true; 
                }
            } 
            else if (order == ORDER_DMY)
            {
                if (result.calendar.IsValidDay(year = AdjustYear(ref result, n2), raw.month, n1, result.era))
                { 
                    result.SetDate(year, raw.month, n1);      // DMY
                    result.flags |= ParseFlags.HaveDate; 
                    return true; 
                }
                else if (result.calendar.IsValidDay(year = AdjustYear(ref result, n1), raw.month, n2, result.era)) 
                {
                    result.SetDate(year, raw.month, n2);      // YMD
                    result.flags |= ParseFlags.HaveDate;
                    return true; 
                }
            } 
 
            result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null);
            return false; 
        }

        private static Boolean GetDayOfYNN(ref DateTimeResult result, ref DateTimeRawInfo raw, DateTimeFormatInfo dtfi) {
 
            if ((result.flags & ParseFlags.HaveDate) != 0) {
                // Multiple dates in the input string 
                result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null); 
                return false;
            } 

            int n1 = raw.GetNumber(0);
            int n2 = raw.GetNumber(1);
            String pattern = dtfi.ShortDatePattern; 

            // by the way, I think I've seen the opposite behavior in the tables. 
            if (dtfi.CultureId == 0x0437) { 
                // 0x0437 = Georgian - Georgia (ka-GE)
                // Very special case for ka-GE: 
                //  Its short date patten is "dd.MM.yyyy" (ORDER_DMY).
                //  However, its long date pattern is "yyyy '\x10ec\x10da\x10d8\x10e1' dd MM, dddd" (ORDER_YDM)
                pattern = dtfi.LongDatePattern;
            } 

            // For compatability, don't throw if we can't determine the order, but default to YMD instead 
            int order; 
            if (GetYearMonthDayOrder(pattern, dtfi, out order) && order == ORDER_YDM) {
                if (SetDateYMD(ref result, raw.year, n2, n1)) { 
                    result.flags |= ParseFlags.HaveDate;
                    return true; // Year + DM
                }
            } 
            else {
                if (SetDateYMD(ref result, raw.year, n1, n2)) { 
                    result.flags |= ParseFlags.HaveDate; 
                    return true; // Year + MD
                } 
            }
            result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null);
            return false;
        } 

        private static Boolean GetDayOfNNY(ref DateTimeResult result, ref DateTimeRawInfo raw, DateTimeFormatInfo dtfi) { 
 
            if ((result.flags & ParseFlags.HaveDate) != 0) {
                // Multiple dates in the input string 
                result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null);
                return false;
            }
 
            int n1 = raw.GetNumber(0);
            int n2 = raw.GetNumber(1); 
 
            int order;
            if (!GetYearMonthDayOrder(dtfi.ShortDatePattern, dtfi, out order)) { 
                result.SetFailure(ParseFailureKind.FormatWithParameter, "Format_BadDatePattern", dtfi.ShortDatePattern);
                return false;
            }
 
            if (order == ORDER_MDY || order == ORDER_YMD) {
                if (SetDateYMD(ref result, raw.year, n1, n2)) { 
                    result.flags |= ParseFlags.HaveDate; 
                    return true; // MD + Year
                } 
            } else {
                if (SetDateYMD(ref result, raw.year, n2, n1)) {
                    result.flags |= ParseFlags.HaveDate;
                    return true; // DM + Year 
                }
            } 
            result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null); 
            return false;
        } 


        private static Boolean GetDayOfYMN(ref DateTimeResult result, ref DateTimeRawInfo raw, DateTimeFormatInfo dtfi) {
 
            if ((result.flags & ParseFlags.HaveDate) != 0) {
                // Multiple dates in the input string 
                result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null); 
                return false;
            } 

            if (SetDateYMD(ref result, raw.year, raw.month, raw.GetNumber(0))) {
                result.flags |= ParseFlags.HaveDate;
                return true; 
            }
            result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null); 
            return false; 
        }
 
        private static Boolean GetDayOfYN(ref DateTimeResult result, ref DateTimeRawInfo raw, DateTimeFormatInfo dtfi)
        {
            if ((result.flags & ParseFlags.HaveDate) != 0) {
                // Multiple dates in the input string 
                result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null);
                return false; 
            } 

            if (SetDateYMD(ref result, raw.year, raw.GetNumber(0), 1)) 
            {
                result.flags |= ParseFlags.HaveDate;
                return true;
            } 
            result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null);
            return false; 
        } 

        private static Boolean GetDayOfYM(ref DateTimeResult result, ref DateTimeRawInfo raw, DateTimeFormatInfo dtfi) 
        {
            if ((result.flags & ParseFlags.HaveDate) != 0) {
                // Multiple dates in the input string
                result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null); 
                return false;
            } 
 
            if (SetDateYMD(ref result, raw.year, raw.month, 1))
            { 
                result.flags |= ParseFlags.HaveDate;
                return true;
            }
            result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null); 
            return false;
        } 
 
        private static void AdjustTimeMark(DateTimeFormatInfo dtfi, ref DateTimeRawInfo raw) {
            // Specail case for culture which uses AM as empty string. 
            // E.g. af-ZA (0x0436)
            //    S1159                  \x0000
            //    S2359                  nm
            // In this case, if we are parsing a string like "2005/09/14 12:23", we will assume this is in AM. 

            if (raw.timeMark == TM.NotSet) { 
                if (dtfi.AMDesignator != null && dtfi.PMDesignator != null) { 
                    if (dtfi.AMDesignator.Length == 0 && dtfi.PMDesignator.Length != 0) {
                        raw.timeMark = TM.AM; 
                    }
                    if (dtfi.PMDesignator.Length == 0 && dtfi.AMDesignator.Length != 0) {
                        raw.timeMark = TM.PM;
                    } 
                }
            } 
        } 

        // 
        // Adjust hour according to the time mark.
        //
        private static Boolean AdjustHour(ref int hour, TM timeMark) {
            if (timeMark != TM.NotSet) { 

                if (timeMark == TM.AM) { 
                    if (hour < 0 || hour > 12) { 
                        return false;
                    } 
                    hour = (hour == 12) ? 0 : hour;
                }
                else {
                    if (hour < 0 || hour > 23) { 
                        return false;
                    } 
                    if (hour < 12) { 
                        hour += 12;
                    } 
                }
            }
            return true;
        } 

        private static Boolean GetTimeOfN(DateTimeFormatInfo dtfi, ref DateTimeResult result, ref DateTimeRawInfo raw) 
        { 
            if ((result.flags & ParseFlags.HaveTime) != 0) {
                // Multiple times in the input string 
                result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null);
                return false;
            }
            // 
            // In this case, we need a time mark. Check if so.
            // 
            if (raw.timeMark == TM.NotSet) 
            {
                result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null); 
                return false;
            }
            result.Hour = raw.GetNumber(0);
            result.flags |= ParseFlags.HaveTime; 
            return true;
        } 
 
        private static Boolean GetTimeOfNN(DateTimeFormatInfo dtfi, ref DateTimeResult result, ref DateTimeRawInfo raw)
        { 
            BCLDebug.Assert(raw.numCount >= 2, "raw.numCount >= 2");
            if ((result.flags & ParseFlags.HaveTime) != 0) {
                // Multiple times in the input string
                result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null); 
                return false;
            } 
 
            result.Hour     = raw.GetNumber(0);
            result.Minute   = raw.GetNumber(1); 
            result.flags |= ParseFlags.HaveTime;
            return true;
        }
 
        private static Boolean GetTimeOfNNN(DateTimeFormatInfo dtfi, ref DateTimeResult result, ref DateTimeRawInfo raw)
        { 
            if ((result.flags & ParseFlags.HaveTime) != 0) { 
                // Multiple times in the input string
                result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null); 
                return false;
            }
            BCLDebug.Assert(raw.numCount >= 3, "raw.numCount >= 3");
            result.Hour = raw.GetNumber(0); 
            result.Minute   = raw.GetNumber(1);
            result.Second   = raw.GetNumber(2); 
            result.flags |= ParseFlags.HaveTime; 
            return true;
        } 

        //
        // Processing terminal state: A Date suffix followed by one number.
        // 
        private static Boolean GetDateOfDSN(ref DateTimeResult result, ref DateTimeRawInfo raw)
        { 
            if (raw.numCount != 1 || result.Day != -1) 
            {
                result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null); 
                return false;
            }
            result.Day = raw.GetNumber(0);
            return true; 
        }
 
        private static Boolean GetDateOfNDS(ref DateTimeResult result, ref DateTimeRawInfo raw) 
        {
            if (result.Month == -1) 
            {
                //Should have a month suffix
                result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null);
                return false; 
            }
            if (result.Year != -1) 
            { 
                // Aleady has a year suffix
                result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null); 
                return false;
            }
            result.Year = AdjustYear(ref result, raw.GetNumber(0));
            result.Day = 1; 
            return true;
        } 
 
        private static Boolean GetDateOfNNDS(ref DateTimeResult result, ref DateTimeRawInfo raw, DateTimeFormatInfo dtfi)
        { 

            // For partial CJK Dates, the only valid formats are with a specified year, followed by two numbers, which
            // will be the Month and Day, and with a specified Month, when the numbers are either the year and day or
            // day and year, depending on the short date pattern. 

            if ((result.flags & ParseFlags.HaveYear) != 0) { 
                if (((result.flags & ParseFlags.HaveMonth) == 0) && ((result.flags & ParseFlags.HaveDay) == 0)) { 
                    if (SetDateYMD(ref result, result.Year = AdjustYear(ref result, raw.year), raw.GetNumber(0), raw.GetNumber(1))) {
                        return true; 
                    }
                }
            }
            else if ((result.flags & ParseFlags.HaveMonth) != 0) { 
                if (((result.flags & ParseFlags.HaveYear) == 0) && ((result.flags & ParseFlags.HaveDay) == 0)) {
                    int order; 
                    if (!GetYearMonthDayOrder(dtfi.ShortDatePattern, dtfi, out order)) { 
                        result.SetFailure(ParseFailureKind.FormatWithParameter, "Format_BadDatePattern", dtfi.ShortDatePattern);
                        return false; 
                    }
                    int year;
                    if (order == ORDER_YMD) {
                        if (SetDateYMD(ref result, year = AdjustYear(ref result, raw.GetNumber(0)), result.Month, raw.GetNumber(1))) { 
                            return true;
                        } 
                    } 
                    else {
                        if (SetDateYMD(ref result, year = AdjustYear(ref result, raw.GetNumber(1)), result.Month, raw.GetNumber(0))){ 
                            return true;
                        }
                    }
                } 
            }
            result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null); 
            return false; 
        }
 
        //
        // A date suffix is found, use this method to put the number into the result.
        //
        private static bool ProcessDateTimeSuffix(ref DateTimeResult result, ref DateTimeRawInfo raw, ref DateTimeToken dtok) 
        {
            switch (dtok.suffix) 
            { 
                case TokenType.SEP_YearSuff:
                    if ((result.flags & ParseFlags.HaveYear) != 0) { 
                        return false;
                    }
                    result.flags |= ParseFlags.HaveYear;
                    result.Year = raw.year = dtok.num; 
                    break;
                case TokenType.SEP_MonthSuff: 
                    if ((result.flags & ParseFlags.HaveMonth) != 0) { 
                        return false;
                    } 
                    result.flags |= ParseFlags.HaveMonth;
                    result.Month= raw.month = dtok.num;
                    break;
                case TokenType.SEP_DaySuff: 
                    if ((result.flags & ParseFlags.HaveDay) != 0) {
                        return false; 
                    } 
                    result.flags |= ParseFlags.HaveDay;
                    result.Day  = dtok.num; 
                    break;
                case TokenType.SEP_HourSuff:
                    if ((result.flags & ParseFlags.HaveHour) != 0) {
                        return false; 
                    }
                    result.flags |= ParseFlags.HaveHour; 
                    result.Hour = dtok.num; 
                    break;
                case TokenType.SEP_MinuteSuff: 
                    if ((result.flags & ParseFlags.HaveMinute) != 0) {
                        return false;
                    }
                    result.flags |= ParseFlags.HaveMinute; 
                    result.Minute = dtok.num;
                    break; 
                case TokenType.SEP_SecondSuff: 
                    if ((result.flags & ParseFlags.HaveSecond) != 0) {
                        return false; 
                    }
                    result.flags |= ParseFlags.HaveSecond;
                    result.Second = dtok.num;
                    break; 
            }
            return true; 
 
        }
 
        ////////////////////////////////////////////////////////////////////////
        //
        // Actions:
        // This is used by DateTime.Parse(). 
        // Process the terminal state for the Hebrew calendar parsing.
        // 
        //////////////////////////////////////////////////////////////////////// 

        internal static Boolean ProcessHebrewTerminalState(DS dps, ref DateTimeResult result, ref DateTimeStyles styles, ref DateTimeRawInfo raw, DateTimeFormatInfo dtfi) { 
            // The following are accepted terminal state for Hebrew date.
            switch (dps) {
                case DS.DX_MNN:
                    // Deal with the default long/short date format when the year number is ambigous (i.e. year < 100). 
                    raw.year = raw.GetNumber(1);
                    if (!dtfi.YearMonthAdjustment(ref raw.year, ref raw.month, true)) { 
                        result.SetFailure(ParseFailureKind.FormatBadDateTimeCalendar, "Format_BadDateTimeCalendar", null); 
                        return false;
                    } 
                    if (!GetDayOfMNN(ref result, ref raw, dtfi)) {
                        return false;
                    }
                    break; 
                case DS.DX_YMN:
                    // Deal with the default long/short date format when the year number is NOT ambigous (i.e. year >= 100). 
                    if (!dtfi.YearMonthAdjustment(ref raw.year, ref raw.month, true)) { 
                        result.SetFailure(ParseFailureKind.FormatBadDateTimeCalendar, "Format_BadDateTimeCalendar", null);
                        return false; 
                    }
                    if (!GetDayOfYMN(ref result, ref raw, dtfi)) {
                        return false;
                    } 
                    break;
                case DS.DX_NM: 
                    // Deal with Month/Day pattern. 
                    GetDefaultYear(ref result, ref styles);
                    if (!dtfi.YearMonthAdjustment(ref result.Year, ref raw.month, true)) { 
                        result.SetFailure(ParseFailureKind.FormatBadDateTimeCalendar, "Format_BadDateTimeCalendar", null);
                        return false;
                    }
                    if (!GetHebrewDayOfNM(ref result, ref raw, dtfi)) { 
                        return false;
                    } 
                    break; 
                case DS.DX_YM:
                    // Deal with Year/Month pattern. 
                    if (!dtfi.YearMonthAdjustment(ref raw.year, ref raw.month, true)) {
                        result.SetFailure(ParseFailureKind.FormatBadDateTimeCalendar, "Format_BadDateTimeCalendar", null);
                        return false;
                    } 
                    if (!GetDayOfYM(ref result, ref raw, dtfi)) {
                        return false; 
                    } 
                    break;
                case DS.TX_N: 
                    // Deal hour + AM/PM
                    if (!GetTimeOfN(dtfi, ref result, ref raw)) {
                        return false;
                    } 
                    break;
                case DS.TX_NN: 
                    if (!GetTimeOfNN(dtfi, ref result, ref raw)) { 
                        return false;
                    } 
                    break;
                case DS.TX_NNN:
                    if (!GetTimeOfNNN(dtfi, ref result, ref raw)) {
                        return false; 
                    }
                    break; 
                default: 
                    result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null);
                    return false; 

            }
            if (dps > DS.ERROR)
            { 
                //
                // We have reached a terminal state. Reset the raw num count. 
                // 
                raw.numCount = 0;
            } 
            return true;
        }

        // 
        // A terminal state has been reached, call the appropriate function to fill in the parsing result.
        // Return true if the state is a terminal state. 
        // 
        internal static Boolean ProcessTerminaltState(DS dps, ref DateTimeResult result, ref DateTimeStyles styles, ref DateTimeRawInfo raw, DateTimeFormatInfo dtfi)
        { 

            switch (dps)
            {
                case DS.DX_NN: 
                    if (!GetDayOfNN(ref result, ref styles, ref raw, dtfi)) {
                        return false; 
                    } 
                    break;
                case DS.DX_NNN: 
                    if (!GetDayOfNNN(ref result, ref raw, dtfi)) {
                        return false;
                    }
                    break; 
                case DS.DX_MN:
                    if (!GetDayOfMN(ref result, ref styles, ref raw, dtfi)) { 
                        return false; 
                    }
                    break; 
                case DS.DX_NM:
                    if (!GetDayOfNM(ref result, ref styles, ref raw, dtfi)) {
                        return false;
                    } 
                    break;
                case DS.DX_MNN: 
                    if (!GetDayOfMNN(ref result, ref raw, dtfi)) { 
                        return false;
                    } 
                    break;
                case DS.DX_DS:
                    // The result has got the correct value. No need to process.
                    break; 
                case DS.DX_YNN:
                    if (!GetDayOfYNN(ref result, ref raw, dtfi)) { 
                        return false; 
                    }
                    break; 
                case DS.DX_NNY:
                    if (!GetDayOfNNY(ref result, ref raw, dtfi)) {
                        return false;
                    } 
                    break;
                case DS.DX_YMN: 
                    if (!GetDayOfYMN(ref result, ref raw, dtfi)) { 
                        return false;
                    } 
                    break;
                case DS.DX_YN:
                    if (!GetDayOfYN(ref result, ref raw, dtfi)) {
                        return false; 
                    }
                    break; 
                case DS.DX_YM: 
                    if (!GetDayOfYM(ref result, ref raw, dtfi)) {
                        return false; 
                    }
                    break;
                case DS.TX_N:
                    if (!GetTimeOfN(dtfi, ref result, ref raw)) { 
                        return false;
                    } 
                    break; 
                case DS.TX_NN:
                    if (!GetTimeOfNN(dtfi, ref result, ref raw)) { 
                        return false;
                    }
                    break;
                case DS.TX_NNN: 
                    if (!GetTimeOfNNN(dtfi, ref result, ref raw)) {
                        return false; 
                    } 
                    break;
                case DS.TX_TS: 
                    // The result has got the correct value. Nothing to do.
                    break;
                case DS.DX_DSN:
                    if (!GetDateOfDSN(ref result, ref raw)) { 
                        return false;
                    } 
                    break; 
                case DS.DX_NDS:
                    if (!GetDateOfNDS(ref result, ref raw)) { 
                        return false;
                    }
                    break;
                case DS.DX_NNDS: 
                    if (!GetDateOfNNDS(ref result, ref raw, dtfi)) {
                        return false; 
                    } 
                    break;
            } 

            if (dps > DS.ERROR)
            {
                // 
                // We have reached a terminal state. Reset the raw num count.
                // 
                raw.numCount = 0; 
            }
            return true; 
        }

        internal static DateTime Parse(String s, DateTimeFormatInfo dtfi, DateTimeStyles styles) {
            DateTimeResult result = new DateTimeResult();       // The buffer to store the parsing result. 
            result.Init();
            if (TryParse(s, dtfi, styles, ref result)) { 
                return result.parsedDate; 
            }
            else { 
                throw GetDateTimeParseException(ref result);
            }
        }
 
        internal static DateTime Parse(String s, DateTimeFormatInfo dtfi, DateTimeStyles styles, out TimeSpan offset) {
            DateTimeResult result = new DateTimeResult();       // The buffer to store the parsing result. 
            result.Init(); 
            result.flags |= ParseFlags.CaptureOffset;
            if (TryParse(s, dtfi, styles, ref result)) { 
                offset = result.timeZoneOffset;
                return result.parsedDate;
            }
            else { 
                throw GetDateTimeParseException(ref result);
            } 
        } 

 
        internal static bool TryParse(String s, DateTimeFormatInfo dtfi, DateTimeStyles styles, out DateTime result) {
            result = DateTime.MinValue;
            DateTimeResult resultData = new DateTimeResult();       // The buffer to store the parsing result.
            resultData.Init(); 
            if (TryParse(s, dtfi, styles, ref resultData)) {
                result = resultData.parsedDate; 
                return true; 
            }
            return false; 
        }

        internal static bool TryParse(String s, DateTimeFormatInfo dtfi, DateTimeStyles styles, out DateTime result, out TimeSpan offset) {
            result = DateTime.MinValue; 
            offset = TimeSpan.Zero;
            DateTimeResult parseResult = new DateTimeResult();       // The buffer to store the parsing result. 
            parseResult.Init(); 
            parseResult.flags |= ParseFlags.CaptureOffset;
            if (TryParse(s, dtfi, styles, ref parseResult)) { 
                result = parseResult.parsedDate;
                offset = parseResult.timeZoneOffset;
                return true;
            } 
            return false;
        } 
 
        //
        // This is the real method to do the parsing work. 
        //
        internal static bool TryParse(String s, DateTimeFormatInfo dtfi, DateTimeStyles styles, ref DateTimeResult result) {
            if (s == null) {
                result.SetFailure(ParseFailureKind.ArgumentNull, "ArgumentNull_String", null, "s"); 
                return false;
            } 
            if (s.Length == 0) { 
                result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null);
                return false; 
            }

            BCLDebug.Assert(dtfi != null, "dtfi == null");
 
            DateTime time;
            // 
            // First try the predefined format. 
            //
            //< 



 

            DS dps             = DS.BEGIN;     // Date Parsing State. 
            bool reachTerminalState = false; 

            DateTimeToken   dtok    = new DateTimeToken();      // The buffer to store the parsing token. 
            dtok.suffix = TokenType.SEP_Unk;
            DateTimeRawInfo raw     = new DateTimeRawInfo();    // The buffer to store temporary parsing information.
            unsafe {
                Int32 * numberPointer = stackalloc Int32[3]; 
                raw.Init(numberPointer);
            } 
            result.calendar = dtfi.Calendar; 
            result.era = Calendar.CurrentEra;
 
            //
            // The string to be parsed. Use a __DTString wrapper so that we can trace the index which
            // indicates the begining of next token.
            // 
            __DTString str = new __DTString(s, dtfi);
 
            str.GetNext(); 

            // 
            // The following loop will break out when we reach the end of the str.
            //
            do {
                // 
                // Call the lexer to get the next token.
                // 
                // If we find a era in Lex(), the era value will be in raw.era. 
                if (!Lex(dps, ref str, ref dtok, ref raw, ref result, ref dtfi)) {
                    return false; 
                }

                //
                // If the token is not unknown, process it. 
                // Otherwise, just discard it.
                // 
                if (dtok.dtt != DTT.Unk) 
                {
                    // 
                    // Check if we got any CJK Date/Time suffix.
                    // Since the Date/Time suffix tells us the number belongs to year/month/day/hour/minute/second,
                    // store the number in the appropriate field in the result.
                    // 
                    if (dtok.suffix != TokenType.SEP_Unk)
                    { 
                        if (!ProcessDateTimeSuffix(ref result, ref raw, ref dtok)) { 
                            result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null);
                            return false; 
                        }

                        dtok.suffix = TokenType.SEP_Unk;  // Reset suffix to SEP_Unk;
                    } 

                    if (dtok.dtt == DTT.NumLocalTimeMark) { 
                        if (dps == DS.D_YNd || dps == DS.D_YN) { 
                            // Consider this as ISO 8601 format:
                            // "yyyy-MM-dd'T'HH:mm:ss"                 1999-10-31T02:00:00 
                            return (ParseISO8601(ref raw, ref str, styles, ref result));
                        }
                        else {
                            result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null); 
                            return false;
                        } 
                    } 

                    // 
                    // Advance to the next state, and continue
                    //
                    dps = dateParsingStates[(int)dps][(int)dtok.dtt];
 
                    if (dps == DS.ERROR)
                    { 
                        result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null); 
                        return false;
                    } 
                    else if (dps > DS.ERROR)
                    {
                        if ((dtfi.FormatFlags & DateTimeFormatFlags.UseHebrewRule) != 0) {
                            if (!ProcessHebrewTerminalState(dps, ref result, ref styles, ref raw, dtfi)) { 
                                return false;
                            } 
                        } else { 
                            if (!ProcessTerminaltState(dps, ref result, ref styles, ref raw, dtfi)) {
                                return false; 
                            }
                        }
                        reachTerminalState = true;
 
                        //
                        // If we have reached a terminal state, start over from DS.BEGIN again. 
                        // For example, when we parsed "1999-12-23 13:30", we will reach a terminal state at "1999-12-23", 
                        // and we start over so we can continue to parse "12:30".
                        // 
                        dps = DS.BEGIN;
                    }
                }
            } while (dtok.dtt != DTT.End && dtok.dtt != DTT.NumEnd && dtok.dtt != DTT.MonthEnd); 

            if (!reachTerminalState) { 
                result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null); 
                return false;
            } 

            AdjustTimeMark(dtfi, ref raw);
            if (!AdjustHour(ref result.Hour, raw.timeMark)) {
                result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null); 
                return false;
            } 
 
            // Check if the parased string only contains hour/minute/second values.
            bool bTimeOnly = (result.Year == -1 && result.Month == -1 && result.Day == -1); 

            //
            // Check if any year/month/day is missing in the parsing string.
            // If yes, get the default value from today's date. 
            //
            if (!CheckDefaultDateTime(ref result, ref result.calendar, styles)) { 
                return false; 
            }
 
            if (!result.calendar.TryToDateTime(result.Year, result.Month, result.Day,
                    result.Hour, result.Minute, result.Second, 0, result.era, out time)) {
                result.SetFailure(ParseFailureKind.FormatBadDateTimeCalendar, "Format_BadDateTimeCalendar", null);
                return false; 
            }
            if (raw.fraction > 0) { 
                time = time.AddTicks((long)Math.Round(raw.fraction * Calendar.TicksPerSecond)); 
            }
 
            //
            // We have to check day of week before we adjust to the time zone.
            // Otherwise, the value of day of week may change after adjustting to the time zone.
            // 
            if (raw.dayOfWeek != -1) {
                // 
                // Check if day of week is correct. 
                //
                if (raw.dayOfWeek != (int)result.calendar.GetDayOfWeek(time)) { 
                    result.SetFailure(ParseFailureKind.Format, "Format_BadDayOfWeek", null);
                    return false;
                }
            } 

            result.parsedDate = time; 
 
            if (!DetermineTimeZoneAdjustments(ref result, styles, bTimeOnly)) {
                return false; 
            }

            return true;
        } 

 
        // Handles time zone adjustments and sets DateTimeKind values as required by the styles 
        private static Boolean DetermineTimeZoneAdjustments(ref DateTimeResult result, DateTimeStyles styles, Boolean bTimeOnly) {
 
            if ((result.flags & ParseFlags.CaptureOffset) != 0) {
                // This is a DateTimeOffset parse, so the offset will actually be captured directly, and
                // no adjustment is required in most cases
                return DateTimeOffsetTimeZonePostProcessing(ref result, styles); 
            }
 
            // The flags AssumeUniveral and AssumeLocal only apply when the input does not have a time zone 
            if ((result.flags & ParseFlags.TimeZoneUsed) == 0) {
 
                // If AssumeLocal or AssumeLocal is used, there will always be a kind specified. As in the
                // case when a time zone is present, it will default to being local unless AdjustToUniversal
                // is present. These comparisons determine whether setting the kind is sufficient, or if a
                // time zone adjustment is required. For consistentcy with the rest of parsing, it is desirable 
                // to fall through to the Adjust methods below, so that there is consist handling of boundary
                // cases like wrapping around on time-only dates and temporarily allowing an adjusted date 
                // to exceed DateTime.MaxValue 
                if ((styles & DateTimeStyles.AssumeLocal) != 0) {
                    if ((styles & DateTimeStyles.AdjustToUniversal) != 0) { 
                        result.flags |= ParseFlags.TimeZoneUsed;
                        result.timeZoneOffset = TimeZone.CurrentTimeZone.GetUtcOffset(result.parsedDate);
                    }
                    else { 
                        result.parsedDate = DateTime.SpecifyKind(result.parsedDate, DateTimeKind.Local);
                        return true; 
                    } 
                }
                else if ((styles & DateTimeStyles.AssumeUniversal) != 0) { 
                    if ((styles & DateTimeStyles.AdjustToUniversal) != 0) {
                        result.parsedDate = DateTime.SpecifyKind(result.parsedDate, DateTimeKind.Utc);
                        return true;
                    } 
                    else {
                        result.flags |= ParseFlags.TimeZoneUsed; 
                        result.timeZoneOffset = TimeSpan.Zero; 
                    }
                } 
                else {
                    // No time zone and no Assume flags, so DateTimeKind.Unspecified is fine
                    BCLDebug.Assert(result.parsedDate.Kind == DateTimeKind.Unspecified, "result.parsedDate.Kind == DateTimeKind.Unspecified");
                    return true; 
                }
            } 
 
            if (((styles & DateTimeStyles.RoundtripKind) != 0) && ((result.flags & ParseFlags.TimeZoneUtc) != 0)) {
                result.parsedDate = DateTime.SpecifyKind(result.parsedDate, DateTimeKind.Utc); 
                return true;
            }

            if ((styles & DateTimeStyles.AdjustToUniversal) != 0) { 
                return (AdjustTimeZoneToUniversal(ref result));
            } 
            return (AdjustTimeZoneToLocal(ref result, bTimeOnly)); 
        }
 
        // Apply validation and adjustments specific to DateTimeOffset
        private static Boolean DateTimeOffsetTimeZonePostProcessing(ref DateTimeResult result, DateTimeStyles styles) {

            // For DateTimeOffset, default to the Utc or Local offset when an offset was not specified by 
            // the input string.
            if ((result.flags & ParseFlags.TimeZoneUsed) == 0) { 
                if ((styles & DateTimeStyles.AssumeUniversal) != 0) { 
                    // AssumeUniversal causes the offset to default to zero (0)
                    result.timeZoneOffset = TimeSpan.Zero; 
                }
                else {
                    // AssumeLocal causes the offset to default to Local.  This flag is on by default for DateTimeOffset.
                    result.timeZoneOffset = TimeZone.CurrentTimeZone.GetUtcOffset(result.parsedDate); 
                }
            } 
 
            Int64 offsetTicks = result.timeZoneOffset.Ticks;
 
            // there should be no overflow, because the offset can be no more than -+100 hours and the date already
            // fits within a DateTime.
            Int64 utcTicks = result.parsedDate.Ticks - offsetTicks;
 
            // For DateTimeOffset, both the parsed time and the corresponding UTC value must be within the boundaries
            // of a DateTime instance. 
            if (utcTicks < DateTime.MinTicks || utcTicks > DateTime.MaxTicks) { 
                result.SetFailure(ParseFailureKind.Format, "Format_UTCOutOfRange", null);
                return false; 
            }


            // For a DateTime offset, the offset must be within +- 14:00 hours. For the regular DateTime.Parse it can 
            // be up to +-99:59. This was unintentional behavior that must be retained on DateTime for compatibility
            // but should not apply to DateTimeOffset. 
            if (offsetTicks < DateTimeOffset.MinOffset || offsetTicks > DateTimeOffset.MaxOffset) { 
                result.SetFailure(ParseFailureKind.Format, "Format_OffsetOutOfRange", null);
                return false; 
            }

            // DateTimeOffset should still honor the AdjustToUniversal flag for consistency with DateTime. It means you
            // want to return an adjusted UTC value, so store the utcTicks in the DateTime and set the offset to zero 
            if ((styles & DateTimeStyles.AdjustToUniversal) != 0) {
                if (((result.flags & ParseFlags.TimeZoneUsed) == 0) && ((styles & DateTimeStyles.AssumeUniversal) == 0)) { 
                    // Handle the special case where the timeZoneOffset was defaulted to Local 
                    Boolean toUtcResult = AdjustTimeZoneToUniversal(ref result);
                    result.timeZoneOffset = TimeSpan.Zero; 
                    return toUtcResult;
                }

                // The constructor should always succeed because of the range check earlier in the function 
                // Althought it is UTC, internally DateTimeOffset does not use this flag
                result.parsedDate = new DateTime(utcTicks, DateTimeKind.Utc); 
                result.timeZoneOffset = TimeSpan.Zero; 
            }
 
            return true;
        }

 
        //
        // Adjust the specified time to universal time based on the supplied timezone. 
        // E.g. when parsing "2001/06/08 14:00-07:00", 
        // the time is 2001/06/08 14:00, and timeZoneOffset = -07:00.
        // The result will be "2001/06/08 21:00" 
        //
        private static Boolean AdjustTimeZoneToUniversal(ref DateTimeResult result) {
            long resultTicks = result.parsedDate.Ticks;
            resultTicks -= result.timeZoneOffset.Ticks; 
            if (resultTicks < 0) {
                resultTicks += Calendar.TicksPerDay; 
            } 

            if (resultTicks < DateTime.MinTicks || resultTicks > DateTime.MaxTicks) { 
                result.SetFailure(ParseFailureKind.Format, "Format_DateOutOfRange", null);
                return false;
            }
            result.parsedDate = new DateTime(resultTicks, DateTimeKind.Utc); 
            return true;
        } 
 
        //
        // Adjust the specified time to universal time based on the supplied timezone, 
        // and then convert to local time.
        // E.g. when parsing "2001/06/08 14:00-04:00", and local timezone is GMT-7.
        // the time is 2001/06/08 14:00, and timeZoneOffset = -05:00.
        // The result will be "2001/06/08 11:00" 
        //
        private static Boolean AdjustTimeZoneToLocal(ref DateTimeResult result, bool bTimeOnly) { 
            long resultTicks = result.parsedDate.Ticks; 
            // Convert to local ticks
            CurrentSystemTimeZone tz = (CurrentSystemTimeZone)TimeZone.CurrentTimeZone; 
            Boolean isAmbiguousLocalDst = false;
            if (resultTicks < Calendar.TicksPerDay) {
                //
                // This is time of day. 
                //
 
                // Adjust timezone. 
                resultTicks -= result.timeZoneOffset.Ticks;
                // If the time is time of day, use the current timezone offset. 
                resultTicks += tz.GetUtcOffset(bTimeOnly ? DateTime.Now: result.parsedDate).Ticks;

                if (resultTicks < 0) {
                    resultTicks += Calendar.TicksPerDay; 
                }
            } else { 
                // Adjust timezone to GMT. 
                resultTicks -= result.timeZoneOffset.Ticks;
                if (resultTicks < DateTime.MinTicks || resultTicks > DateTime.MaxTicks) { 
                    // If the result ticks is greater than DateTime.MaxValue, we can not create a DateTime from this ticks.
                    // In this case, keep using the old code.
                    resultTicks += tz.GetUtcOffset(result.parsedDate).Ticks;
                } else { 
                    // Convert the GMT time to local time.
                    resultTicks += tz.GetUtcOffsetFromUniversalTime(new DateTime(resultTicks), ref isAmbiguousLocalDst); 
                } 
            }
            if (resultTicks < DateTime.MinTicks || resultTicks > DateTime.MaxTicks) { 
                result.parsedDate = DateTime.MinValue;
                result.SetFailure(ParseFailureKind.Format, "Format_DateOutOfRange", null);
                return false;
            } 
            result.parsedDate = new DateTime(resultTicks, DateTimeKind.Local, isAmbiguousLocalDst);
            return true; 
        } 

        // 
        // Parse the ISO8601 format string found during Parse();
        //
        //
        private static bool ParseISO8601(ref DateTimeRawInfo raw, ref __DTString str, DateTimeStyles styles, ref DateTimeResult result) { 
            if (raw.year < 0 || raw.GetNumber(0) < 0 || raw.GetNumber(1) < 0) {
            } 
            str.Index--; 
            int hour, minute;
            int second = 0; 
            double partSecond = 0;

            str.SkipWhiteSpaces();
            if (!ParseDigits(ref str, 2, out hour)) { 
                result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null);
                return false; 
            } 
            str.SkipWhiteSpaces();
            if (!str.Match(':')) { 
                result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null);
                return false;
            }
            str.SkipWhiteSpaces(); 
            if (!ParseDigits(ref str, 2, out minute)) {
                result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null); 
                return false; 
            }
            str.SkipWhiteSpaces(); 
            if (str.Match(':')) {
                str.SkipWhiteSpaces();
                if (!ParseDigits(ref str, 2, out second)) {
                    result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null); 
                    return false;
                } 
                if (str.Match('.')) { 
                    if (!ParseFraction(ref str, out partSecond)) {
                        result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null); 
                        return false;
                    }
                    str.Index--;
                } 
                str.SkipWhiteSpaces();
            } 
            if (str.GetNext()) { 
                char ch = str.GetChar();
                if (ch == '+' || ch == '-') { 
                    result.flags |= ParseFlags.TimeZoneUsed;
                    if (!ParseTimeZone(ref str, ref result.timeZoneOffset)) {
                        result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null);
                        return false; 
                    }
                } else if (ch == 'Z' || ch == 'z') { 
                    result.flags |= ParseFlags.TimeZoneUsed; 
                    result.timeZoneOffset = TimeSpan.Zero;
                    result.flags |= ParseFlags.TimeZoneUtc; 
                } else {
                    str.Index--;
                }
                str.SkipWhiteSpaces(); 
                if (str.Match('#')) {
                    if (!VerifyValidPunctuation(ref str)) { 
                        result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null); 
                        return false;
                    } 
                    str.SkipWhiteSpaces();
                }
                if (str.Match('\0')) {
                    if (!VerifyValidPunctuation(ref str)) { 
                        result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null);
                        return false; 
                    } 
                }
                if (str.GetNext()) { 
                    // If this is true, there were non-white space characters remaining in the DateTime
                    result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null);
                    return false;
                } 
            }
 
            DateTime time; 
            Calendar calendar = GregorianCalendar.GetDefaultInstance();
            if (!calendar.TryToDateTime(raw.year, raw.GetNumber(0), raw.GetNumber(1), 
                    hour, minute, second, 0, result.era, out time)) {
                result.SetFailure(ParseFailureKind.FormatBadDateTimeCalendar, "Format_BadDateTimeCalendar", null);
                return false;
            } 

            time = time.AddTicks((long)Math.Round(partSecond * Calendar.TicksPerSecond)); 
            result.parsedDate = time; 
            if (!DetermineTimeZoneAdjustments(ref result, styles, false)) {
                return false; 
            }
            return true;
        }
 

        //////////////////////////////////////////////////////////////////////// 
        // 
        // Actions:
        //    Parse the current word as a Hebrew number. 
        //      This is used by DateTime.ParseExact().
        //
        ////////////////////////////////////////////////////////////////////////
 
        internal static bool MatchHebrewDigits(ref __DTString str, int digitLen, out int number) {
            number = 0; 
 
            // Create a context object so that we can parse the Hebrew number text character by character.
            HebrewNumberParsingContext context = new HebrewNumberParsingContext(0); 

            // Set this to ContinueParsing so that we will run the following while loop in the first time.
            HebrewNumberParsingState state = HebrewNumberParsingState.ContinueParsing;
 
            while (state == HebrewNumberParsingState.ContinueParsing && str.GetNext()) {
                state = HebrewNumber.ParseByChar(str.GetChar(), ref context); 
            } 

            if (state == HebrewNumberParsingState.FoundEndOfHebrewNumber) { 
                // If we have reached a terminal state, update the result and returns.
                number = context.result;
                return (true);
            } 

            // If we run out of the character before reaching FoundEndOfHebrewNumber, or 
            // the state is InvalidHebrewNumber or ContinueParsing, we fail to match a Hebrew number. 
            // Return an error.
            return false; 
        }

        /*=================================ParseDigits==================================
        **Action: Parse the number string in __DTString that are formatted using 
        **        the following patterns:
        **        "0", "00", and "000..0" 
        **Returns: the integer value 
        **Arguments:    str: a __DTString.  The parsing will start from the
        **              next character after str.Index. 
        **Exceptions: FormatException if error in parsing number.
        ==============================================================================*/

        internal static bool ParseDigits(ref __DTString str, int digitLen, out int result) { 
            if (digitLen == 1) {
                // 1 really means 1 or 2 for this call 
                return ParseDigits(ref str, 1, 2, out result); 
            }
            else { 
                return ParseDigits(ref str, digitLen, digitLen, out result);
            }
        }
 
        internal static bool ParseDigits(ref __DTString str, int minDigitLen, int maxDigitLen, out int result) {
            BCLDebug.Assert(minDigitLen > 0, "minDigitLen > 0"); 
            BCLDebug.Assert(maxDigitLen < 9, "maxDigitLen < 9"); 
            BCLDebug.Assert(minDigitLen <= maxDigitLen, "minDigitLen <= maxDigitLen");
            result = 0; 
            int startingIndex = str.Index;
            int tokenLength = 0;
            while (tokenLength < maxDigitLen) {
                if (!str.GetNextDigit()) { 
                    str.Index--;
                    break; 
                } 
                result = result * 10 + str.GetDigit();
                tokenLength++; 
            }
            if (tokenLength < minDigitLen) {
                str.Index = startingIndex;
                return false; 
            }
            return true; 
        } 

        /*=================================ParseFractionExact================================== 
        **Action: Parse the number string in __DTString that are formatted using
        **        the following patterns:
        **        "0", "00", and "000..0"
        **Returns: the fraction value 
        **Arguments:    str: a __DTString.  The parsing will start from the
        **              next character after str.Index. 
        **Exceptions: FormatException if error in parsing number. 
        ==============================================================================*/
 
        private static bool ParseFractionExact(ref __DTString str, int maxDigitLen,  ref double result) {
            if (!str.GetNextDigit()) {
                str.Index--;
                return false; 
            }
            result = str.GetDigit(); 
 
            int digitLen = 1;
            for (; digitLen < maxDigitLen; digitLen++) { 
                if (!str.GetNextDigit()) {
                    str.Index--;
                    break;
                } 
                result = result * 10 + str.GetDigit();
            } 
 
            result = ((double)result / Math.Pow(10, digitLen));
            return (digitLen == maxDigitLen); 
        }

        /*=================================ParseSign==================================
        **Action: Parse a positive or a negative sign. 
        **Returns:      true if postive sign.  flase if negative sign.
        **Arguments:    str: a __DTString.  The parsing will start from the 
        **              next character after str.Index. 
        **Exceptions:   FormatException if end of string is encountered or a sign
        **              symbol is not found. 
        ==============================================================================*/

        private static bool ParseSign(ref __DTString str, ref bool result) {
            if (!str.GetNext()) { 
                // A sign symbol ('+' or '-') is expected. However, end of string is encountered.
                return false; 
            } 
            char ch = str.GetChar();
            if (ch == '+') { 
                result = true;
                return (true);
            } else if (ch == '-') {
                result = false; 
                return (true);
            } 
            // A sign symbol ('+' or '-') is expected. 
            return false;
        } 

        /*=================================ParseTimeZoneOffset==================================
        **Action: Parse the string formatted using "z", "zz", "zzz" in DateTime.Format().
        **Returns: the TimeSpan for the parsed timezone offset. 
        **Arguments:    str: a __DTString.  The parsing will start from the
        **              next character after str.Index. 
        **              len: the repeated number of the "z" 
        **Exceptions: FormatException if errors in parsing.
        ==============================================================================*/ 

        private static bool ParseTimeZoneOffset(ref __DTString str, int len, ref TimeSpan result) {
            bool isPositive = true;
            int hourOffset; 
            int minuteOffset = 0;
 
            switch (len) { 
                case 1:
                case 2: 
                    if (!ParseSign(ref str, ref isPositive)) {
                        return (false);
                    }
                    if (!ParseDigits(ref str, len, out hourOffset)) { 
                        return (false);
                    } 
                    break; 
                default:
                    if (!ParseSign(ref str, ref isPositive)) { 
                        return (false);
                    }

                    // Parsing 1 digit will actually parse 1 or 2. 
                    if (!ParseDigits(ref str, 1, out hourOffset)) {
                        return (false); 
                    } 
                    // ':' is optional.
                    if (str.Match(":")) { 
                        // Found ':'
                        if (!ParseDigits(ref str, 2, out minuteOffset)) {
                            return (false);
                        } 
                    } else {
                        // Since we can not match ':', put the char back. 
                        str.Index--; 
                        if (!ParseDigits(ref str, 2, out minuteOffset)) {
                            return (false); 
                        }
                    }
                    break;
            } 
            if (minuteOffset < 0 || minuteOffset >= 60) {
                return false; 
            } 

            result = (new TimeSpan(hourOffset, minuteOffset, 0)); 
            if (!isPositive) {
                result = result.Negate();
            }
            return (true); 
        }
 
        /*=================================MatchAbbreviatedMonthName================================== 
        **Action: Parse the abbreviated month name from string starting at str.Index.
        **Returns: A value from 1 to 12 for the first month to the twelveth month. 
        **Arguments:    str: a __DTString.  The parsing will start from the
        **              next character after str.Index.
        **Exceptions: FormatException if an abbreviated month name can not be found.
        ==============================================================================*/ 

        private static bool MatchAbbreviatedMonthName(ref __DTString str, DateTimeFormatInfo dtfi, ref int result) { 
            int maxMatchStrLen = 0; 
            result = -1;
            if (str.GetNext()) { 
                //
                // Scan the month names (note that some calendars has 13 months) and find
                // the matching month name which has the max string length.
                // We need to do this because some cultures (e.g. "cs-CZ") which have 
                // abbreviated month names with the same prefix.
                // 
                int monthsInYear = (dtfi.GetMonthName(13).Length == 0 ? 12: 13); 
                for (int i = 1; i <= monthsInYear; i++) {
                    String searchStr = dtfi.GetAbbreviatedMonthName(i); 
                    int matchStrLen = searchStr.Length;
                    if ( dtfi.HasSpacesInMonthNames
                            ? str.MatchSpecifiedWords(searchStr, false, ref matchStrLen)
                            : str.MatchSpecifiedWord(searchStr)) { 
                        if (matchStrLen > maxMatchStrLen) {
                            maxMatchStrLen = matchStrLen; 
                            result = i; 
                        }
                    } 
                }

                // Search leap year form.
                if ((dtfi.FormatFlags & DateTimeFormatFlags.UseLeapYearMonth) != 0) { 
                    int tempResult = str.MatchLongestWords(dtfi.internalGetLeapYearMonthNames(), ref maxMatchStrLen);
                    // We found a longer match in the leap year month name.  Use this as the result. 
                    // The result from MatchLongestWords is 0 ~ length of word array. 
                    // So we increment the result by one to become the month value.
                    if (tempResult >= 0) { 
                        result = tempResult + 1;
                    }
                }
 

            } 
            if (result > 0) { 
                str.Index += (maxMatchStrLen - 1);
                return (true); 
            }
            return false;
        }
 
        /*=================================MatchMonthName==================================
        **Action: Parse the month name from string starting at str.Index. 
        **Returns: A value from 1 to 12 indicating the first month to the twelveth month. 
        **Arguments:    str: a __DTString.  The parsing will start from the
        **              next character after str.Index. 
        **Exceptions: FormatException if a month name can not be found.
        ==============================================================================*/

        private static bool MatchMonthName(ref __DTString str, DateTimeFormatInfo dtfi, ref int result) { 
            int maxMatchStrLen = 0;
            result = -1; 
            if (str.GetNext()) { 
                //
                // Scan the month names (note that some calendars has 13 months) and find 
                // the matching month name which has the max string length.
                // We need to do this because some cultures (e.g. "vi-VN") which have
                // month names with the same prefix.
                // 
                int monthsInYear = (dtfi.GetMonthName(13).Length == 0 ? 12: 13);
                for (int i = 1; i <= monthsInYear; i++) { 
                    String searchStr = dtfi.GetMonthName(i); 
                    int matchStrLen = searchStr.Length;
                    if ( dtfi.HasSpacesInMonthNames 
                            ? str.MatchSpecifiedWords(searchStr, false, ref matchStrLen)
                            : str.MatchSpecifiedWord(searchStr)) {
                        if (matchStrLen > maxMatchStrLen) {
                            maxMatchStrLen = matchStrLen; 
                            result = i;
                        } 
                    } 
                }
 
                // Search genitive form.
                if ((dtfi.FormatFlags & DateTimeFormatFlags.UseGenitiveMonth) != 0) {
                    int tempResult = str.MatchLongestWords(dtfi.MonthGenitiveNames, ref maxMatchStrLen);
                    // We found a longer match in the genitive month name.  Use this as the result. 
                    // The result from MatchLongestWords is 0 ~ length of word array.
                    // So we increment the result by one to become the month value. 
                    if (tempResult >= 0) { 
                        result = tempResult + 1;
                    } 
                }

                // Search leap year form.
                if ((dtfi.FormatFlags & DateTimeFormatFlags.UseLeapYearMonth) != 0) { 
                    int tempResult = str.MatchLongestWords(dtfi.internalGetLeapYearMonthNames(), ref maxMatchStrLen);
                    // We found a longer match in the leap year month name.  Use this as the result. 
                    // The result from MatchLongestWords is 0 ~ length of word array. 
                    // So we increment the result by one to become the month value.
                    if (tempResult >= 0) { 
                        result = tempResult + 1;
                    }
                }
 

            } 
 
            if (result > 0) {
                str.Index += (maxMatchStrLen - 1); 
                return (true);
            }
            return false;
        } 

        /*=================================MatchAbbreviatedDayName================================== 
        **Action: Parse the abbreviated day of week name from string starting at str.Index. 
        **Returns: A value from 0 to 6 indicating Sunday to Saturday.
        **Arguments:    str: a __DTString.  The parsing will start from the 
        **              next character after str.Index.
        **Exceptions: FormatException if a abbreviated day of week name can not be found.
        ==============================================================================*/
 
        private static bool MatchAbbreviatedDayName(ref __DTString str, DateTimeFormatInfo dtfi, ref int result) {
            int maxMatchStrLen = 0; 
            result = -1; 
            if (str.GetNext()) {
                for (DayOfWeek i = DayOfWeek.Sunday; i <= DayOfWeek.Saturday; i++) { 
                    String searchStr = dtfi.GetAbbreviatedDayName(i);
                    int matchStrLen = searchStr.Length;
                    if ( dtfi.HasSpacesInDayNames
                            ? str.MatchSpecifiedWords(searchStr, false, ref matchStrLen) 
                            : str.MatchSpecifiedWord(searchStr)) {
                        if (matchStrLen > maxMatchStrLen) { 
                            maxMatchStrLen = matchStrLen; 
                            result = (int)i;
                        } 
                    }
                }
            }
            if (result >= 0) { 
                str.Index += maxMatchStrLen - 1;
                return (true); 
            } 
            return false;
        } 

        /*=================================MatchDayName==================================
        **Action: Parse the day of week name from string starting at str.Index.
        **Returns: A value from 0 to 6 indicating Sunday to Saturday. 
        **Arguments:    str: a __DTString.  The parsing will start from the
        **              next character after str.Index. 
        **Exceptions: FormatException if a day of week name can not be found. 
        ==============================================================================*/
 
        private static bool MatchDayName(ref __DTString str, DateTimeFormatInfo dtfi, ref int result) {
            // Turkish (tr-TR) got day names with the same prefix.
            int maxMatchStrLen = 0;
            result = -1; 
            if (str.GetNext()) {
                for (DayOfWeek i = DayOfWeek.Sunday; i <= DayOfWeek.Saturday; i++) { 
                    String searchStr = dtfi.GetDayName(i); 
                    int matchStrLen = searchStr.Length;
                    if ( dtfi.HasSpacesInDayNames 
                            ? str.MatchSpecifiedWords(searchStr, false, ref matchStrLen)
                            : str.MatchSpecifiedWord(searchStr)) {
                        if (matchStrLen > maxMatchStrLen) {
                            maxMatchStrLen = matchStrLen; 
                            result = (int)i;
                        } 
                    } 
                }
            } 
            if (result >= 0) {
                str.Index += maxMatchStrLen - 1;
                return (true);
            } 
            return false;
        } 
 
        /*=================================MatchEraName==================================
        **Action: Parse era name from string starting at str.Index. 
        **Returns: An era value.
        **Arguments:    str: a __DTString.  The parsing will start from the
        **              next character after str.Index.
        **Exceptions: FormatException if an era name can not be found. 
        ==============================================================================*/
 
        private static bool MatchEraName(ref __DTString str, DateTimeFormatInfo dtfi, ref int result) { 
            if (str.GetNext()) {
                int[] eras = dtfi.Calendar.Eras; 

                if (eras != null) {
                    for (int i = 0; i < eras.Length; i++) {
                        String searchStr = dtfi.GetEraName(eras[i]); 
                        if (str.MatchSpecifiedWord(searchStr)) {
                            str.Index += (searchStr.Length - 1); 
                            result = eras[i]; 
                            return (true);
                        } 
                        searchStr = dtfi.GetAbbreviatedEraName(eras[i]);
                        if (str.MatchSpecifiedWord(searchStr)) {
                            str.Index += (searchStr.Length - 1);
                            result = eras[i]; 
                            return (true);
                        } 
                    } 
                }
            } 
            return false;
        }

        /*=================================MatchTimeMark================================== 
        **Action: Parse the time mark (AM/PM) from string starting at str.Index.
        **Returns: TM_AM or TM_PM. 
        **Arguments:    str: a __DTString.  The parsing will start from the 
        **              next character after str.Index.
        **Exceptions: FormatException if a time mark can not be found. 
        ==============================================================================*/

        private static bool MatchTimeMark(ref __DTString str, DateTimeFormatInfo dtfi, ref TM result) {
            result = TM.NotSet; 
            // In some cultures have empty strings in AM/PM mark. E.g. af-ZA (0x0436), the AM mark is "", and PM mark is "nm".
            if (dtfi.AMDesignator.Length == 0) { 
                result = TM.AM; 
            }
            if (dtfi.PMDesignator.Length == 0) { 
                result = TM.PM;
            }

            if (str.GetNext()) { 
                String searchStr = dtfi.AMDesignator;
                if (searchStr.Length > 0) { 
                    if (str.MatchSpecifiedWord(searchStr)) { 
                        // Found an AM timemark with length > 0.
                        str.Index += (searchStr.Length - 1); 
                        result = TM.AM;
                        return (true);
                    }
                } 
                searchStr = dtfi.PMDesignator;
                if (searchStr.Length > 0) { 
                    if (str.MatchSpecifiedWord(searchStr)) { 
                        // Found a PM timemark with length > 0.
                        str.Index += (searchStr.Length - 1); 
                        result = TM.PM;
                        return (true);
                    }
                } 
                str.Index--; // Undo the GetNext call.
            } 
            if (result != TM.NotSet) { 
                // If one of the AM/PM marks is empty string, return the result.
                return (true); 
            }
            return false;
        }
 
        /*=================================MatchAbbreviatedTimeMark==================================
        **Action: Parse the abbreviated time mark (AM/PM) from string starting at str.Index. 
        **Returns: TM_AM or TM_PM. 
        **Arguments:    str: a __DTString.  The parsing will start from the
        **              next character after str.Index. 
        **Exceptions: FormatException if a abbreviated time mark can not be found.
        ==============================================================================*/

        private static bool MatchAbbreviatedTimeMark(ref __DTString str, DateTimeFormatInfo dtfi, ref TM result) { 
            // NOTENOTE : the assumption here is that abbreviated time mark is the first
            // character of the AM/PM designator.  If this invariant changes, we have to 
            // change the code below. 
            if (str.GetNext())
            { 
                if (str.GetChar() == dtfi.AMDesignator[0]) {
                    result = TM.AM;
                    return (true);
                } 
                if (str.GetChar() == dtfi.PMDesignator[0]) {
                    result = TM.PM; 
                    return (true); 
                }
            } 
            return false;
        }

        /*=================================CheckNewValue================================== 
        **Action: Check if currentValue is initialized.  If not, return the newValue.
        **        If yes, check if the current value is equal to newValue.  Return false 
        **        if they are not equal.  This is used to check the case like "d" and "dd" are both 
        **        used to format a string.
        **Returns: the correct value for currentValue. 
        **Arguments:
        **Exceptions:
        ==============================================================================*/
 
        private static bool CheckNewValue(ref int currentValue, int newValue, char patternChar, ref DateTimeResult result) {
            if (currentValue == -1) { 
                currentValue = newValue; 
                return (true);
            } else { 
                if (newValue != currentValue) {
                    result.SetFailure(ParseFailureKind.FormatWithParameter, "Format_RepeatDateTimePattern", patternChar);
                    return (false);
                } 
            }
            return (true); 
        } 

        private static DateTime GetDateTimeNow(ref DateTimeResult result, ref DateTimeStyles styles) { 
            if ((result.flags & ParseFlags.CaptureOffset) != 0) {
                if ((result.flags & ParseFlags.TimeZoneUsed) != 0) {
                    // use the supplied offset to calculate 'Now'
                    return new DateTime(DateTime.UtcNow.Ticks + result.timeZoneOffset.Ticks, DateTimeKind.Unspecified); 
                }
                else if ((styles & DateTimeStyles.AssumeUniversal) != 0) { 
                    // assume the offset is Utc 
                    return DateTime.UtcNow;
                } 
            }

            // assume the offset is Local
            return DateTime.Now; 
        }
 
        private static bool CheckDefaultDateTime(ref DateTimeResult result, ref Calendar cal, DateTimeStyles styles) { 

            if ((result.flags & ParseFlags.CaptureOffset) != 0) { 
                // DateTimeOffset.Parse should allow dates without a year, but only if there is also no time zone marker;
                // e.g. "May 1 5pm" is OK, but "May 1 5pm -08:30" is not.  This is somewhat pragmatic, since we would
                // have to rearchitect parsing completely to allow this one case to correctly handle things like leap
                // years and leap months.  Is is an extremely corner case, and DateTime is basically incorrect in that 
                // case today.
                // 
                // values like "11:00Z" or "11:00 -3:00" are also acceptable 
                //
                // if ((month or day is set) and (year is not set and time zone is set)) 
                //
                if (  ((result.Month != -1) || (result.Day != -1))
                    && ((result.Year == -1 || ((result.flags & ParseFlags.YearDefault) != 0)) && (result.flags & ParseFlags.TimeZoneUsed) != 0) ) {
                    result.SetFailure(ParseFailureKind.Format, "Format_MissingIncompleteDate", null); 
                    return false;
                } 
            } 

 
            if ((result.Year == -1) || (result.Month == -1) || (result.Day == -1)) {
                /*
                The following table describes the behaviors of getting the default value
                when a certain year/month/day values are missing. 

                An "X" means that the value exists.  And "--" means that value is missing. 
 
                Year    Month   Day =>  ResultYear  ResultMonth     ResultDay       Note
 
                X       X       X       Parsed year Parsed month    Parsed day
                X       X       --      Parsed Year Parsed month    First day       If we have year and month, assume the first day of that month.
                X       --      X       Parsed year First month     Parsed day      If the month is missing, assume first month of that year.
                X       --      --      Parsed year First month     First day       If we have only the year, assume the first day of that year. 

                --      X       X       CurrentYear Parsed month    Parsed day      If the year is missing, assume the current year. 
                --      X       --      CurrentYear Parsed month    First day       If we have only a month value, assume the current year and current day. 
                --      --      X       CurrentYear First month     Parsed day      If we have only a day value, assume current year and first month.
                --      --      --      CurrentYear Current month   Current day     So this means that if the date string only contains time, you will get current date. 

                */

                DateTime now = GetDateTimeNow(ref result, ref styles); 
                if (result.Month == -1 && result.Day == -1) {
                    if (result.Year == -1) { 
                        if ((styles & DateTimeStyles.NoCurrentDateDefault) != 0) { 
                            // If there is no year/month/day values, and NoCurrentDateDefault flag is used,
                            // set the year/month/day value to the beginning year/month/day of DateTime(). 
                            // Note we should be using Gregorian for the year/month/day.
                            cal = GregorianCalendar.GetDefaultInstance();
                            result.Year = result.Month = result.Day = 1;
                        } else { 
                            // Year/Month/Day are all missing.
                            result.Year = cal.GetYear(now); 
                            result.Month = cal.GetMonth(now); 
                            result.Day = cal.GetDayOfMonth(now);
                        } 
                    } else {
                        // Month/Day are both missing.
                        result.Month = 1;
                        result.Day = 1; 
                    }
                } else { 
                    if (result.Year == -1) { 
                        result.Year = cal.GetYear(now);
                    } 
                    if (result.Month == -1) {
                        result.Month = 1;
                    }
                    if (result.Day == -1) { 
                        result.Day = 1;
                    } 
                } 
            }
            // Set Hour/Minute/Second to zero if these value are not in str. 
            if (result.Hour   == -1) result.Hour = 0;
            if (result.Minute == -1) result.Minute = 0;
            if (result.Second == -1) result.Second = 0;
            if (result.era == -1) result.era = Calendar.CurrentEra; 
            return true;
        } 
 
        // Expand a pre-defined format string (like "D" for long date) to the real format that
        // we are going to use in the date time parsing. 
        // This method also set the dtfi according/parseInfo to some special pre-defined
        // formats.
        //
        private static String ExpandPredefinedFormat(String format, ref DateTimeFormatInfo dtfi, ref ParsingInfo parseInfo, ref DateTimeResult result) { 
            //
            // Check the format to see if we need to override the dtfi to be InvariantInfo, 
            // and see if we need to set up the userUniversalTime flag. 
            //
            switch (format[0]) { 
                case 'o':
                case 'O':       // Round Trip Format
                    parseInfo.calendar = GregorianCalendar.GetDefaultInstance();
                    dtfi = DateTimeFormatInfo.InvariantInfo; 
                    break;
                case 'r': 
                case 'R':       // RFC 1123 Standard.  (in Universal time) 
                    parseInfo.calendar = GregorianCalendar.GetDefaultInstance();
                    dtfi = DateTimeFormatInfo.InvariantInfo; 

                    if ((result.flags & ParseFlags.CaptureOffset) != 0) {
                        result.flags |= ParseFlags.Rfc1123Pattern;
                    } 
                    break;
                case 's':       // Sortable format (in local time) 
                    dtfi = DateTimeFormatInfo.InvariantInfo; 
                    parseInfo.calendar = GregorianCalendar.GetDefaultInstance();
                    break; 
                case 'u':       // Universal time format in sortable format.
                    parseInfo.calendar = GregorianCalendar.GetDefaultInstance();
                    dtfi = DateTimeFormatInfo.InvariantInfo;
 
                    if ((result.flags & ParseFlags.CaptureOffset) != 0) {
                        result.flags |= ParseFlags.UtcSortPattern; 
                    } 
                    break;
                case 'U':       // Universal time format with culture-dependent format. 
                    parseInfo.calendar = GregorianCalendar.GetDefaultInstance();
                    result.flags |= ParseFlags.TimeZoneUsed;
                    result.timeZoneOffset = new TimeSpan(0);
                    result.flags |= ParseFlags.TimeZoneUtc; 
                    if (dtfi.Calendar.GetType() != typeof(GregorianCalendar)) {
                        dtfi = (DateTimeFormatInfo)dtfi.Clone(); 
                        dtfi.Calendar = GregorianCalendar.GetDefaultInstance(); 
                    }
                    break; 
            }

            //
            // Expand the pre-defined format character to the real format from DateTimeFormatInfo. 
            //
            return (DateTimeFormat.GetRealFormat(format, dtfi)); 
        } 

        // Given a specified format character, parse and update the parsing result. 
        //
        private static bool ParseByFormat(
            ref __DTString str,
            ref __DTString format, 
            ref ParsingInfo parseInfo,
            DateTimeFormatInfo dtfi, 
            ref DateTimeResult result) { 

            int tokenLen = 0; 
            int tempYear = 0, tempMonth = 0, tempDay = 0, tempDayOfWeek = 0, tempHour = 0, tempMinute = 0, tempSecond = 0;
            double tempFraction = 0;
            TM tempTimeMark = 0;
 
            char ch = format.GetChar();
 
            switch (ch) { 
                case 'y':
                    tokenLen = format.GetRepeatCount(); 
                    bool parseResult;
                    if (dtfi.HasForceTwoDigitYears) {
                        parseResult = ParseDigits(ref str, 1, 4, out tempYear);
                    } 
                    else {
                        if (tokenLen <= 2) { 
                            parseInfo.fUseTwoDigitYear = true; 
                        }
                        parseResult = ParseDigits(ref str, tokenLen, out tempYear); 
                    }
                    if (!parseResult && parseInfo.fCustomNumberParser) {
                        parseResult = parseInfo.parseNumberDelegate(ref str, tokenLen, out tempYear);
                    } 
                    if (!parseResult) {
                        result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null); 
                        return (false); 
                    }
                    if (!CheckNewValue(ref result.Year, tempYear, ch, ref result)) { 
                        return (false);
                    }
                    break;
                case 'M': 
                    tokenLen = format.GetRepeatCount();
                    if (tokenLen <= 2) { 
                        if (!ParseDigits(ref str, tokenLen, out tempMonth)) { 
                            if (!parseInfo.fCustomNumberParser ||
                                !parseInfo.parseNumberDelegate(ref str, tokenLen, out tempMonth)) { 
                                result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null);
                                return (false);
                            }
                        } 
                    } else {
                        if (tokenLen == 3) { 
                            if (!MatchAbbreviatedMonthName(ref str, dtfi, ref tempMonth)) { 
                                result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null);
                                return (false); 
                            }
                        } else {
                            if (!MatchMonthName(ref str, dtfi, ref tempMonth)) {
                                result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null); 
                                return (false);
                            } 
                        } 
                        result.flags |= ParseFlags.ParsedMonthName;
                    } 
                    if (!CheckNewValue(ref result.Month, tempMonth, ch, ref result)) {
                        return (false);
                    }
                    break; 
                case 'd':
                    // Day & Day of week 
                    tokenLen = format.GetRepeatCount(); 
                    if (tokenLen <= 2) {
                        // "d" & "dd" 

                        if (!ParseDigits(ref str, tokenLen, out tempDay)) {
                            if (!parseInfo.fCustomNumberParser ||
                                !parseInfo.parseNumberDelegate(ref str, tokenLen, out tempDay)) { 
                                result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null);
                                return (false); 
                            } 
                        }
                        if (!CheckNewValue(ref result.Day, tempDay, ch, ref result)) { 
                            return (false);
                        }
                    } else {
                        if (tokenLen == 3) { 
                            // "ddd"
                            if (!MatchAbbreviatedDayName(ref str, dtfi, ref tempDayOfWeek)) { 
                                result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null); 
                                return (false);
                            } 
                        } else {
                            // "dddd*"
                            if (!MatchDayName(ref str, dtfi, ref tempDayOfWeek)) {
                                result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null); 
                                return (false);
                            } 
                        } 
                        if (!CheckNewValue(ref parseInfo.dayOfWeek, tempDayOfWeek, ch, ref result)) {
                            return (false); 
                        }
                    }
                    break;
                case 'g': 
                    tokenLen = format.GetRepeatCount();
                    // Put the era value in result.era. 
                    if (!MatchEraName(ref str, dtfi, ref result.era)) { 
                        result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null);
                        return (false); 
                    }
                    break;
                case 'h':
                    parseInfo.fUseHour12 = true; 
                    tokenLen = format.GetRepeatCount();
                    if (!ParseDigits(ref str, (tokenLen < 2? 1 : 2), out tempHour)) { 
                        result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null); 
                        return (false);
                    } 
                    if (!CheckNewValue(ref result.Hour, tempHour, ch, ref result)) {
                        return (false);
                    }
                    break; 
                case 'H':
                    tokenLen = format.GetRepeatCount(); 
                    if (!ParseDigits(ref str, (tokenLen < 2? 1 : 2), out tempHour)) { 
                        result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null);
                        return (false); 
                    }
                    if (!CheckNewValue(ref result.Hour, tempHour, ch, ref result)) {
                        return (false);
                    } 
                    break;
                case 'm': 
                    tokenLen = format.GetRepeatCount(); 
                    if (!ParseDigits(ref str, (tokenLen < 2? 1 : 2), out tempMinute)) {
                        result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null); 
                        return (false);
                    }
                    if (!CheckNewValue(ref result.Minute, tempMinute, ch, ref result)) {
                        return (false); 
                    }
                    break; 
                case 's': 
                    tokenLen = format.GetRepeatCount();
                    if (!ParseDigits(ref str, (tokenLen < 2? 1 : 2), out tempSecond)) { 
                        result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null);
                        return (false);
                    }
                    if (!CheckNewValue(ref result.Second, tempSecond, ch, ref result)) { 
                        return (false);
                    } 
                    break; 
                case 'f':
                case 'F': 
                    tokenLen = format.GetRepeatCount();
                    if (tokenLen <= DateTimeFormat.MaxSecondsFractionDigits) {
                        if (!ParseFractionExact(ref str, tokenLen, ref tempFraction)) {
                            if (ch == 'f') { 
                                result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null);
                                return (false); 
                            } 
                        }
                        if (result.fraction < 0) { 
                            result.fraction = tempFraction;
                        } else {
                            if (tempFraction != result.fraction) {
                                result.SetFailure(ParseFailureKind.FormatWithParameter, "Format_RepeatDateTimePattern", ch); 
                                return (false);
                            } 
                        } 
                    } else {
                        result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null); 
                        return (false);
                    }
                    break;
                case 't': 
                    // AM/PM designator
                    tokenLen = format.GetRepeatCount(); 
                    if (tokenLen == 1) { 
                        if (!MatchAbbreviatedTimeMark(ref str, dtfi, ref tempTimeMark)) {
                            result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null); 
                            return (false);
                        }
                    } else {
                        if (!MatchTimeMark(ref str, dtfi, ref tempTimeMark)) { 
                            result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null);
                            return (false); 
                        } 
                    }
 
                    if (parseInfo.timeMark == TM.NotSet) {
                        parseInfo.timeMark = tempTimeMark;
                    }
                    else { 
                        if (parseInfo.timeMark != tempTimeMark) {
                            result.SetFailure(ParseFailureKind.FormatWithParameter, "Format_RepeatDateTimePattern", ch); 
                            return (false); 
                        }
                    } 
                    break;
                case 'z':
                    // timezone offset
                    tokenLen = format.GetRepeatCount(); 
                    {
                        TimeSpan tempTimeZoneOffset = new TimeSpan(0); 
                        if (!ParseTimeZoneOffset(ref str, tokenLen, ref tempTimeZoneOffset)) { 
                            result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null);
                            return (false); 
                        }
                        if ((result.flags & ParseFlags.TimeZoneUsed) != 0 && tempTimeZoneOffset != result.timeZoneOffset) {
                            result.SetFailure(ParseFailureKind.FormatWithParameter, "Format_RepeatDateTimePattern", 'z');
                            return (false); 
                        }
                        result.timeZoneOffset = tempTimeZoneOffset; 
                        result.flags |= ParseFlags.TimeZoneUsed; 
                    }
                    break; 
                case 'Z':
                    if ((result.flags & ParseFlags.TimeZoneUsed) != 0 && result.timeZoneOffset != TimeSpan.Zero) {
                        result.SetFailure(ParseFailureKind.FormatWithParameter, "Format_RepeatDateTimePattern", 'Z');
                        return (false); 
                    }
 
                    result.flags |= ParseFlags.TimeZoneUsed; 
                    result.timeZoneOffset = new TimeSpan(0);
                    result.flags |= ParseFlags.TimeZoneUtc; 

                    // The updating of the indexes is to reflect that ParseExact MatchXXX methods assume that
                    // they need to increment the index and Parse GetXXX do not. Since we are calling a Parse
                    // method from inside ParseExact we need to adjust this. Long term, we should try to 
                    // eliminate this discrepancy.
                    str.Index++; 
                    if (!GetTimeZoneName(ref str)) { 
                        result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null);
                        return false; 
                    }
                    str.Index--;
                    break;
                case 'K': 
                    // This should parse either as a blank, the 'Z' character or a local offset like "-07:00"
                    if (str.Match('Z')) { 
                        if ((result.flags & ParseFlags.TimeZoneUsed) != 0 && result.timeZoneOffset != TimeSpan.Zero) { 
                            result.SetFailure(ParseFailureKind.FormatWithParameter, "Format_RepeatDateTimePattern", 'K');
                            return (false); 
                        }

                        result.flags |= ParseFlags.TimeZoneUsed;
                        result.timeZoneOffset = new TimeSpan(0); 
                        result.flags |= ParseFlags.TimeZoneUtc;
                    } 
                    else if (str.Match('+') || str.Match('-')) { 
                        str.Index--; // Put the character back for the parser
                        TimeSpan tempTimeZoneOffset = new TimeSpan(0); 
                        if (!ParseTimeZoneOffset(ref str, 3, ref tempTimeZoneOffset)) {
                            result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null);
                            return (false);
                        } 
                        if ((result.flags & ParseFlags.TimeZoneUsed) != 0 && tempTimeZoneOffset != result.timeZoneOffset) {
                            result.SetFailure(ParseFailureKind.FormatWithParameter, "Format_RepeatDateTimePattern", 'K'); 
                            return (false); 
                        }
                        result.timeZoneOffset = tempTimeZoneOffset; 
                        result.flags |= ParseFlags.TimeZoneUsed;
                    }
                    // Otherwise it is unspecified and we consume no characters
                    break; 
                case ':':
                    if (!str.Match(dtfi.TimeSeparator)) { 
                        // A time separator is expected. 
                        result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null);
                        return false; 
                    }
                    break;
                case '/':
                    if (!str.Match(dtfi.DateSeparator)) { 
                        // A date separator is expected.
                        result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null); 
                        return false; 
                    }
                    break; 
                case '\"':
                case '\'':
                    StringBuilder enquotedString = new StringBuilder();
                    // Use ParseQuoteString so that we can handle escape characters within the quoted string. 
                    if (!TryParseQuoteString(format.Value, format.Index, enquotedString, out tokenLen)) {
                        result.SetFailure(ParseFailureKind.FormatWithParameter, "Format_BadQuote", ch); 
                        return (false); 
                    }
                    format.Index += tokenLen - 1; 

                    // Some cultures uses space in the quoted string.  E.g. Spanish has long date format as:
                    // "dddd, dd' de 'MMMM' de 'yyyy".  When inner spaces flag is set, we should skip whitespaces if there is space
                    // in the quoted string. 
                    String quotedStr = enquotedString.ToString();
 
                    for (int i = 0; i < quotedStr.Length; i++) { 
                        if (quotedStr[i] == ' ' && parseInfo.fAllowInnerWhite) {
                            str.SkipWhiteSpaces(); 
                        } else if (!str.Match(quotedStr[i])) {
                            // Can not find the matching quoted string.
                            result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null);
                            return false; 
                        }
                    } 
 
                    // The "r" and "u" formats incorrectly quoted 'GMT' and 'Z', respectively.  We cannot
                    // correct this mistake for DateTime.ParseExact for compatibility reasons, but we can 
                    // fix it for DateTimeOffset.ParseExact as DateTimeOffset has not been publically released
                    // with this issue.
                    if ((result.flags & ParseFlags.CaptureOffset) != 0) {
                        if ((result.flags & ParseFlags.Rfc1123Pattern) != 0 && quotedStr == GMTName) { 
                            result.flags |= ParseFlags.TimeZoneUsed;
                            result.timeZoneOffset = TimeSpan.Zero; 
                        } 
                        else if ((result.flags & ParseFlags.UtcSortPattern) != 0 && quotedStr == ZuluName) {
                            result.flags |= ParseFlags.TimeZoneUsed; 
                            result.timeZoneOffset = TimeSpan.Zero;
                        }
                    }
 
                    break;
                case '%': 
                    // Skip this so we can get to the next pattern character. 
                    // Used in case like "%d", "%y"
 
                    // Make sure the next character is not a '%' again.
                    if (format.Index >= format.Value.Length - 1 || format.Value[format.Index + 1] == '%') {
                        result.SetFailure(ParseFailureKind.Format, "Format_BadFormatSpecifier", null);
                        return false; 
                    }
                    break; 
                case '\\': 
                    // Escape character. For example, "\d".
                    // Get the next character in format, and see if we can 
                    // find a match in str.
                    if (format.GetNext()) {
                        if (!str.Match(format.GetChar())) {
                            // Can not find a match for the escaped character. 
                            result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null);
                            return false; 
                        } 
                    } else {
                        result.SetFailure(ParseFailureKind.Format, "Format_BadFormatSpecifier", null); 
                        return false;
                    }
                    break;
                case '.': 
                    if (!str.Match(ch)) {
                        if (format.GetNext()) { 
                            // If we encounter the pattern ".F", and the dot is not present, it is an optional 
                            // second fraction and we can skip this format.
                            if (format.Match('F')) { 
                                format.GetRepeatCount();
                                break;
                            }
                        } 
                        result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null);
                        return false; 
                    } 
                    break;
                default: 
                    if (ch == ' ') {
                        if (parseInfo.fAllowInnerWhite) {
                            // Skip whitespaces if AllowInnerWhite.
                            // Do nothing here. 
                        } else {
                            if (!str.Match(ch)) { 
                                // If the space does not match, and trailing space is allowed, we do 
                                // one more step to see if the next format character can lead to
                                // successful parsing. 
                                // This is used to deal with special case that a empty string can match
                                // a specific pattern.
                                // The example here is af-ZA, which has a time format like "hh:mm:ss tt".  However,
                                // its AM symbol is "" (empty string).  If fAllowTrailingWhite is used, and time is in 
                                // the AM, we will trim the whitespaces at the end, which will lead to a failure
                                // when we are trying to match the space before "tt". 
                                if (parseInfo.fAllowTrailingWhite) { 
                                    if (format.GetNext()) {
                                        if (ParseByFormat(ref str, ref format, ref parseInfo, dtfi, ref result)) { 
                                            return (true);
                                        }
                                    }
                                } 
                                result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null);
                                return false; 
                            } 
                            // Found a macth.
                        } 
                    } else {
                        if (format.MatchSpecifiedWord(GMTName)) {
                            format.Index += (GMTName.Length - 1);
                            // Found GMT string in format.  This means the DateTime string 
                            // is in GMT timezone.
                            result.flags |= ParseFlags.TimeZoneUsed; 
                            result.timeZoneOffset = TimeSpan.Zero; 
                            if (!str.Match(GMTName)) {
                                result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null); 
                                return false;
                            }
                        } else if (!str.Match(ch)) {
                            // ch is expected. 
                            result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null);
                            return false; 
                        } 
                    }
                    break; 
            } // switch
            return (true);
        }
 
        //
        // The pos should point to a quote character. This method will 
        // get the string encloed by the quote character. 
        //
        internal static bool TryParseQuoteString(String format, int pos, StringBuilder result, out int returnValue) { 
            //
            // NOTE : pos will be the index of the quote character in the 'format' string.
            //
            returnValue = 0; 
            int formatLen = format.Length;
            int beginPos = pos; 
            char quoteChar = format[pos++]; // Get the character used to quote the following string. 

            bool foundQuote = false; 
            while (pos < formatLen) {
                char ch = format[pos++];
                if (ch == quoteChar) {
                    foundQuote = true; 
                    break;
                } 
                else if (ch == '\\') { 
                    // The following are used to support escaped character.
                    // Escaped character is also supported in the quoted string. 
                    // Therefore, someone can use a format like "'minute:' mm\"" to display:
                    //  minute: 45"
                    // because the second double quote is escaped.
                    if (pos < formatLen) { 
                        result.Append(format[pos++]);
                    } else { 
                        // 
                        // This means that '\' is at the end of the formatting string.
                        // 
                        return false;
                    }
                } else {
                    result.Append(ch); 
                }
            } 
 
            if (!foundQuote) {
                // Here we can't find the matching quote. 
                return false;
            }

            // 
            // Return the character count including the begin/end quote characters and enclosed string.
            // 
            returnValue = (pos - beginPos); 
            return true;
        } 


        /*=================================DoStrictParse==================================
        **Action: Do DateTime parsing using the format in formatParam. 
        **Returns: The parsed DateTime.
        **Arguments: 
        **Exceptions: 
        **
        **Notes: 
        **  When the following general formats are used, InvariantInfo is used in dtfi:
        **      'r', 'R', 's'.
        **  When the following general formats are used, the time is assumed to be in Universal time.
        ** 
        **Limitations:
        **  Only GregarianCalendar is supported for now. 
        **  Only support GMT timezone. 
        ==============================================================================*/
 
        private static bool DoStrictParse(
            String s,
            String formatParam,
            DateTimeStyles styles, 
            DateTimeFormatInfo dtfi,
            ref DateTimeResult result) { 
 
            bool bTimeOnly = false;
            ParsingInfo parseInfo = new ParsingInfo(); 
            parseInfo.Init();

            parseInfo.calendar = dtfi.Calendar;
            parseInfo.fAllowInnerWhite = ((styles & DateTimeStyles.AllowInnerWhite) != 0); 
            parseInfo.fAllowTrailingWhite = ((styles & DateTimeStyles.AllowTrailingWhite) != 0);
 
            if (formatParam.Length == 1) { 
                if (((result.flags & ParseFlags.CaptureOffset) != 0) && formatParam[0] == 'U') {
                    // The 'U' format is not allowed for DateTimeOffset 
                    result.SetFailure(ParseFailureKind.Format, "Format_BadFormatSpecifier", null);
                    return false;
                }
                formatParam = ExpandPredefinedFormat(formatParam, ref dtfi, ref parseInfo, ref result); 
            }
            result.calendar = parseInfo.calendar; 
 
            if (parseInfo.calendar.ID == Calendar.CAL_HEBREW) {
                parseInfo.parseNumberDelegate = m_hebrewNumberParser; 
                parseInfo.fCustomNumberParser = true;
            }

            // Reset these values to negative one so that we could throw exception 
            // if we have parsed every item twice.
            result.Hour = result.Minute = result.Second = -1; 
 
            __DTString format = new __DTString(formatParam, dtfi, false);
            __DTString str = new __DTString(s, dtfi, false); 

            if (parseInfo.fAllowTrailingWhite) {
                // Trim trailing spaces if AllowTrailingWhite.
                format.TrimTail(); 
                format.RemoveTrailingInQuoteSpaces();
                str.TrimTail(); 
            } 

            if ((styles & DateTimeStyles.AllowLeadingWhite) != 0) { 
                format.SkipWhiteSpaces();
                format.RemoveLeadingInQuoteSpaces();
                str.SkipWhiteSpaces();
            } 

            // 
            // Scan every character in format and match the pattern in str. 
            //
            while (format.GetNext()) { 
                // We trim inner spaces here, so that we will not eat trailing spaces when
                // AllowTrailingWhite is not used.
                if (parseInfo.fAllowInnerWhite) {
                    str.SkipWhiteSpaces(); 
                }
                if (!ParseByFormat(ref str, ref format, ref parseInfo, dtfi, ref result)) { 
                   return (false); 
                }
            } 
            if (str.Index < str.Value.Length - 1) {
                // There are still remaining character in str.
                result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null);
                return false; 
            }
 
            if (parseInfo.fUseTwoDigitYear && ((dtfi.FormatFlags & DateTimeFormatFlags.UseHebrewRule) == 0)) { 
                // A two digit year value is expected. Check if the parsed year value is valid.
                if (result.Year >= 100) { 
                    result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null);
                    return false;
                }
                result.Year = parseInfo.calendar.ToFourDigitYear(result.Year); 
            }
 
            if (parseInfo.fUseHour12) { 
                if (parseInfo.timeMark == TM.NotSet) {
                    // hh is used, but no AM/PM designator is specified. 
                    // Assume the time is AM.
                    // Don't throw exceptions in here becasue it is very confusing for the caller.
                    // I always got confused myself when I use "hh:mm:ss" to parse a time string,
                    // and ParseExact() throws on me (because I didn't use the 24-hour clock 'HH'). 
                    parseInfo.timeMark = TM.AM;
                } 
                if (result.Hour > 12) { 
                    // AM/PM is used, but the value for HH is too big.
                    result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null); 
                    return false;
                }
                if (parseInfo.timeMark == TM.AM) {
                    if (result.Hour == 12) { 
                        result.Hour = 0;
                    } 
                } else { 
                    result.Hour = (result.Hour == 12) ? 12 : result.Hour + 12;
                } 
            }

            // Check if the parased string only contains hour/minute/second values.
            bTimeOnly = (result.Year == -1 && result.Month == -1 && result.Day == -1); 
            if (!CheckDefaultDateTime(ref result, ref parseInfo.calendar, styles)) {
                return false; 
            } 

            if (!bTimeOnly && dtfi.HasYearMonthAdjustment) { 
                if (!dtfi.YearMonthAdjustment(ref result.Year, ref result.Month, ((result.flags & ParseFlags.ParsedMonthName) != 0))) {
                    result.SetFailure(ParseFailureKind.FormatBadDateTimeCalendar, "Format_BadDateTimeCalendar", null);
                    return false;
                } 
            }
            if (!parseInfo.calendar.TryToDateTime(result.Year, result.Month, result.Day, 
                    result.Hour, result.Minute, result.Second, 0, result.era, out result.parsedDate)) { 
                result.SetFailure(ParseFailureKind.FormatBadDateTimeCalendar, "Format_BadDateTimeCalendar", null);
                return false; 
            }
            if (result.fraction > 0) {
                result.parsedDate = result.parsedDate.AddTicks((long)Math.Round(result.fraction * Calendar.TicksPerSecond));
            } 

            // 
            // We have to check day of week before we adjust to the time zone. 
            // It is because the value of day of week may change after adjusting
            // to the time zone. 
            //
            if (parseInfo.dayOfWeek != -1) {
                //
                // Check if day of week is correct. 
                //
                if (parseInfo.dayOfWeek != (int)parseInfo.calendar.GetDayOfWeek(result.parsedDate)) { 
                    result.SetFailure(ParseFailureKind.Format, "Format_BadDayOfWeek", null); 
                    return false;
                } 
            }


            if (!DetermineTimeZoneAdjustments(ref result, styles, bTimeOnly)) { 
                return false;
            } 
            return true; 
        }
 
        private static Exception GetDateTimeParseException(ref DateTimeResult result) {
            switch (result.failure) {
                case ParseFailureKind.ArgumentNull:
                    return new ArgumentNullException(result.failureArgumentName, Environment.GetResourceString(result.failureMessageID)); 
                case ParseFailureKind.Format:
                    return new FormatException(Environment.GetResourceString(result.failureMessageID)); 
                case ParseFailureKind.FormatWithParameter: 
                    return new FormatException(Environment.GetResourceString(result.failureMessageID, result.failureMessageFormatArgument));
                case ParseFailureKind.FormatBadDateTimeCalendar: 
                    return new FormatException(Environment.GetResourceString(result.failureMessageID, result.calendar));
                default:
                    BCLDebug.Assert(false, "Unkown DateTimeParseFailure: " + result);
                    return null; 

            } 
        } 
   }
 

    //
    // This is a string parsing helper which wraps a String object.
    // It has a Index property which tracks 
    // the current parsing pointer of the string.
    // 
    internal 
    struct __DTString
    { 

        //
        // Value propery: stores the real string to be parsed.
        // 
        internal String Value;
 
        // 
        // Index property: points to the character that we are currently parsing.
        // 
        internal int Index;

        // The length of Value string.
        internal int len; 

        // The current chracter to be looked at. 
        internal char m_current; 

        private CompareInfo m_info; 
        // Flag to indicate if we encouter an digit, we should check for token or not.
        // In some cultures, such as mn-MN, it uses "\x0031\x00a0\x0434\x04af\x0433\x044d\x044d\x0440\x00a0\x0441\x0430\x0440" in month names.
        private bool m_checkDigitToken;
 
        internal __DTString(String str, DateTimeFormatInfo dtfi, bool checkDigitToken) : this (str, dtfi)
        { 
            m_checkDigitToken = checkDigitToken; 
        }
 
        internal __DTString(String str, DateTimeFormatInfo dtfi)
        {
            Index = -1;
            Value = str; 
            len = Value.Length;
 
            m_current = '\0'; 
            if (dtfi != null)
            { 
                m_info = dtfi.CompareInfo;
                m_checkDigitToken = ((dtfi.FormatFlags & DateTimeFormatFlags.UseDigitPrefixInTokens) != 0);
            } else
            { 
                m_info = Thread.CurrentThread.CurrentCulture.CompareInfo;
                m_checkDigitToken = false; 
            } 
        }
 
        internal CompareInfo CompareInfo
        {
            get { return m_info; }
        } 

        // 
        // Advance the Index. 
        // Return true if Index is NOT at the end of the string.
        // 
        // Typical usage:
        // while (str.GetNext())
        // {
        //     char ch = str.GetChar() 
        // }
        internal bool GetNext() { 
            Index++; 
            if (Index < len) {
                m_current = Value[Index]; 
                return (true);
            }
            return (false);
        } 

        internal bool Advance(int count) { 
            BCLDebug.Assert(Index + count <= len, "__DTString::Advance: Index + count <= len"); 
            Index += count;
            if (Index < len) { 
                m_current = Value[Index];
                return (true);
            }
            return (false); 
        }
 
 
        // Used by DateTime.Parse() to get the next token.
        internal void GetRegularToken(out TokenType tokenType, out int tokenValue, DateTimeFormatInfo dtfi) { 
            tokenValue = 0;
            if (Index >= len) {
                tokenType = TokenType.EndOfString;
                return; 
            }
 
            tokenType = TokenType.UnknownToken; 

Start: 
            if (DateTimeParse.IsDigit(m_current)) {
                // This is a digit.
                tokenValue = m_current - '0';
                int value; 
                int start = Index;
 
                // 
                // Collect other digits.
                // 
                while (++Index < len)
                {
                    m_current = Value[Index];
                    value = m_current - '0'; 
                    if (value >= 0 && value <= 9) {
                        tokenValue = tokenValue * 10 + value; 
                    } else { 
                        break;
                    } 
                }
                if (Index - start > DateTimeParse.MaxDateTimeNumberDigits) {
                    tokenType = TokenType.NumberToken;
                    tokenValue = -1; 
                } else if (Index - start < 3) {
                    tokenType = TokenType.NumberToken; 
                } else { 
                    // If there are more than 3 digits, assume that it's a year value.
                    tokenType = TokenType.YearNumberToken; 
                }
                if (m_checkDigitToken)
                {
                    int save = Index; 
                    char saveCh = m_current;
                    // Re-scan using the staring Index to see if this is a token. 
                    Index = start;  // To include the first digit. 
                    m_current = Value[Index];
                    TokenType tempType; 
                    int tempValue;
                    // This DTFI has tokens starting with digits.
                    // E.g. mn-MN has month name like "\x0031\x00a0\x0434\x04af\x0433\x044d\x044d\x0440\x00a0\x0441\x0430\x0440"
                    if (dtfi.Tokenize(TokenType.RegularTokenMask, out tempType, out tempValue, ref this)) 
                    {
                        tokenType = tempType; 
                        tokenValue = tempValue; 
                        // This is a token, so the Index has been advanced propertly in DTFI.Tokenizer().
                    } else 
                    {
                        // Use the number token value.
                        // Restore the index.
                        Index = save; 
                        m_current = saveCh;
                    } 
 
                }
 
            } else if (Char.IsWhiteSpace( m_current)) {
                // Just skip to the next character.
                while (++Index < len) {
                    m_current = Value[Index]; 
                    if (!(Char.IsWhiteSpace(m_current))) {
                        goto Start; 
                    } 
                }
                // We have reached the end of string. 
                tokenType = TokenType.EndOfString;
            } else {
                dtfi.Tokenize(TokenType.RegularTokenMask, out tokenType, out tokenValue, ref this);
            } 
        }
 
        internal TokenType GetSeparatorToken(DateTimeFormatInfo dtfi, out int indexBeforeSeparator, out char charBeforeSeparator) { 
            indexBeforeSeparator = Index;
            charBeforeSeparator = m_current; 
            TokenType tokenType;
            if (!SkipWhiteSpaceCurrent()) {
                // Reach the end of the string.
                return (TokenType.SEP_End); 
            }
            if (!DateTimeParse.IsDigit(m_current)) { 
                // Not a digit.  Tokenize it. 
                int tokenValue;
                bool found = dtfi.Tokenize(TokenType.SeparatorTokenMask, out tokenType, out tokenValue, ref this); 
                if (!found) {
                    tokenType = TokenType.SEP_Space;
                }
            } else { 
                // Do nothing here.  If we see a number, it will not be a separator. There is no need wasting time trying to find the
                // separator token. 
                tokenType = TokenType.SEP_Space; 
            }
            return (tokenType); 
        }

        internal bool MatchSpecifiedWord(String target) {
            return MatchSpecifiedWord(target, target.Length + Index); 
        }
 
        internal bool MatchSpecifiedWord(String target, int endIndex) { 
            int count = endIndex - Index;
 
            if (count != target.Length) {
                return false;
            }
 
            if (Index + count > len) {
                return false; 
            } 

            return (m_info.Compare(Value, Index, count, target, 0, count, CompareOptions.IgnoreCase)==0); 
        }

        private static Char[] WhiteSpaceChecks = new Char[] { ' ', '\u00A0' };
 
        internal bool MatchSpecifiedWords(String target, bool checkWordBoundary, ref int matchLength) {
            int valueRemaining = Value.Length - Index; 
            matchLength = target.Length; 

            if (matchLength > valueRemaining || m_info.Compare(Value, Index, matchLength, target, 0, matchLength, CompareOptions.IgnoreCase) !=0) { 
                // Check word by word
                int targetPosition = 0;                 // Where we are in the target string
                int thisPosition = Index;         // Where we are in this string
                int wsIndex = target.IndexOfAny(WhiteSpaceChecks, targetPosition); 
                if (wsIndex == -1) {
                    return false; 
                } 
                do {
                    int segmentLength = wsIndex - targetPosition; 
                    if (thisPosition >= Value.Length - segmentLength) { // Subtraction to prevent overflow.
                        return false;
                    }
                    if (segmentLength == 0) { 
                        // If segmentLength == 0, it means that we have leading space in the target string.
                        // In that case, skip the leading spaces in the target and this string. 
                        matchLength--; 
                    } else {
                        // Make sure we also have whitespace in the input string 
                        if (!Char.IsWhiteSpace(Value[thisPosition + segmentLength])) {
                            return false;
                        }
                        if (m_info.Compare(Value, thisPosition, segmentLength, target, targetPosition, segmentLength, CompareOptions.IgnoreCase) !=0) { 
                            return false;
                        } 
                        // Advance the input string 
                        thisPosition = thisPosition + segmentLength + 1;
                    } 
                    // Advance our target string
                    targetPosition = wsIndex + 1;

 
                    // Skip past multiple whitespace
                    while (thisPosition < Value.Length && Char.IsWhiteSpace(Value[thisPosition])) { 
                        thisPosition++; 
                        matchLength++;
                    } 
                } while ((wsIndex = target.IndexOfAny(WhiteSpaceChecks, targetPosition)) >= 0);
                // now check the last segment;
                if (targetPosition < target.Length) {
                    int segmentLength = target.Length - targetPosition; 
                    if (thisPosition > Value.Length - segmentLength) {
                        return false; 
                    } 
                    if (m_info.Compare(Value, thisPosition, segmentLength, target, targetPosition, segmentLength, CompareOptions.IgnoreCase) !=0) {
                        return false; 
                    }
                }
            }
 
            if (checkWordBoundary) {
                int nextCharIndex = Index + matchLength; 
                if (nextCharIndex < Value.Length) { 
                    if (Char.IsLetter(Value[nextCharIndex])) {
                        return (false); 
                    }
                }
            }
            return (true); 
        }
 
        // 
        // Check to see if the string starting from Index is a prefix of
        // str. 
        // If a match is found, true value is returned and Index is updated to the next character to be parsed.
        // Otherwise, Index is unchanged.
        //
        internal bool Match(String str) { 
            if (++Index >= len) {
                return (false); 
            } 

            if (str.Length > (Value.Length - Index)) { 
                return false;
            }

            if (m_info.Compare(Value, Index, str.Length, str, 0, str.Length, CompareOptions.Ordinal)==0) { 
                // Update the Index to the end of the matching string.
                // So the following GetNext()/Match() opeartion will get 
                // the next character to be parsed. 
                Index += (str.Length - 1);
                return (true); 
            }
            return (false);
        }
 
        internal bool Match(char ch) {
            if (++Index >= len) { 
                return (false); 
            }
            if (Value[Index] == ch) { 
                m_current = ch;
                return (true);
            }
            Index--; 
            return (false);
        } 
 
        //
        //  Actions: From the current position, try matching the longest word in the specified string array. 
        //      E.g. words[] = {"AB", "ABC", "ABCD"}, if the current position points to a substring like "ABC DEF",
        //          MatchLongestWords(words, ref MaxMatchStrLen) will return 1 (the index), and maxMatchLen will be 3.
        //  Returns:
        //      The index that contains the longest word to match 
        //  Arguments:
        //      words   The string array that contains words to search. 
        //      maxMatchStrLen  [in/out] the initailized maximum length.  This parameter can be used to 
        //          find the longest match in two string arrays.
        // 
        internal int MatchLongestWords(String[] words, ref int maxMatchStrLen) {
            int result = -1;
            for (int i = 0; i < words.Length; i++) {
                String word = words[i]; 
                int matchLength = word.Length;
                if (MatchSpecifiedWords(word, false, ref matchLength)) { 
                    if (matchLength > maxMatchStrLen) { 
                        maxMatchStrLen = matchLength;
                        result = i; 
                    }
                }
            }
 
            return (result);
        } 
 
        //
        // Get the number of repeat character after the current character. 
        // For a string "hh:mm:ss" at Index of 3. GetRepeatCount() = 2, and Index
        // will point to the second ':'.
        //
        internal int GetRepeatCount() { 
            char repeatChar = Value[Index];
            int pos = Index + 1; 
            while ((pos < len) && (Value[pos] == repeatChar)) { 
                pos++;
            } 
            int repeatCount = (pos - Index);
            // Update the Index to the end of the repeated characters.
            // So the following GetNext() opeartion will get
            // the next character to be parsed. 
            Index = pos - 1;
            return (repeatCount); 
        } 

        // Return false when end of string is encountered or a non-digit character is found. 
        internal bool GetNextDigit() {
            if (++Index >= len) {
                return (false);
            } 
            return (DateTimeParse.IsDigit(Value[Index]));
        } 
 
        //
        // Get the current character. 
        //
        internal char GetChar() {
            BCLDebug.Assert(Index >= 0 && Index < len, "Index >= 0 && Index < len");
            return (Value[Index]); 
        }
 
        // 
        // Convert the current character to a digit, and return it.
        // 
        internal int GetDigit() {
            BCLDebug.Assert(Index >= 0 && Index < len, "Index >= 0 && Index < len");
            BCLDebug.Assert(DateTimeParse.IsDigit(Value[Index]), "IsDigit(Value[Index])");
            return (Value[Index] - '0'); 
        }
 
        // 
        // Eat White Space ahead of the current position
        // 
        // Return false if end of string is encountered.
        //
        internal void SkipWhiteSpaces()
        { 
            // Look ahead to see if the next character
            // is a whitespace. 
            while (Index+1 < len) 
            {
                char ch = Value[Index+1]; 
                if (!Char.IsWhiteSpace(ch)) {
                    return;
                }
                Index++; 
            }
            return; 
        } 

        // 
        // Skip white spaces from the current position
        //
        // Return false if end of string is encountered.
        // 
        internal bool SkipWhiteSpaceCurrent()
        { 
            if (Index >= len) { 
                return (false);
            } 

            if (!Char.IsWhiteSpace(m_current))
            {
                return (true); 
            }
 
            while (++Index < len) 
            {
                m_current = Value[Index]; 
                if (!Char.IsWhiteSpace(m_current))
                {
                    return (true);
                } 
                // Nothing here.
            } 
            return (false); 
        }
 
        internal void TrimTail() {
            int i = len - 1;
            while (i >= 0 && Char.IsWhiteSpace(Value[i])) {
                i--; 
            }
            Value = Value.Substring(0, i + 1); 
            len = Value.Length; 
        }
 
        // Trim the trailing spaces within a quoted string.
        // Call this after TrimTail() is done.
        internal void RemoveTrailingInQuoteSpaces() {
            int i = len - 1; 
            if (i <= 1) {
                return; 
            } 
            char ch = Value[i];
            // Check if the last character is a quote. 
            if (ch == '\'' || ch == '\"') {
                if (Char.IsWhiteSpace(Value[i-1])) {
                    i--;
                    while (i >= 1 && Char.IsWhiteSpace(Value[i-1])) { 
                        i--;
                    } 
                    Value = Value.Remove(i, Value.Length - 1 - i); 
                    len = Value.Length;
                } 
            }
        }

        // Trim the leading spaces within a quoted string. 
        // Call this after the leading spaces before quoted string are trimmed.
        internal void RemoveLeadingInQuoteSpaces() { 
            if (len <= 2) { 
                return;
            } 
            int i = 0;
            char ch = Value[i];
            // Check if the last character is a quote.
            if (ch == '\'' || ch == '\"') { 
                while ((i + 1) < len && Char.IsWhiteSpace(Value[i+1])) {
                    i++; 
                } 
                if (i != 0) {
                    Value = Value.Remove(1, i); 
                    len = Value.Length;
                }
            }
        } 

        internal DTSubString GetSubString() { 
            DTSubString sub = new DTSubString(); 
            sub.index = Index;
            sub.s = Value; 
            while (Index + sub.length < len) {
                DTSubStringType currentType;
                Char ch = Value[Index + sub.length];
                if (ch >= '0' && ch <= '9') { 
                    currentType = DTSubStringType.Number;
                } 
                else { 
                    currentType = DTSubStringType.Other;
                } 

                if (sub.length == 0) {
                    sub.type = currentType;
                } 
                else {
                    if (sub.type != currentType) { 
                        break; 
                    }
                } 
                sub.length++;
                if (currentType == DTSubStringType.Number) {
                    // Incorporate the number into the value
                    // Limit the digits to prevent overflow 
                    if (sub.length > DateTimeParse.MaxDateTimeNumberDigits) {
                        sub.type = DTSubStringType.Invalid; 
                        return sub; 
                    }
                    int number = ch - '0'; 
                    BCLDebug.Assert(number >= 0 && number <= 9, "number >= 0 && number <= 9");
                    sub.value = sub.value * 10 + number;
                }
                else { 
                    // For non numbers, just return this length 1 token. This should be expanded
                    // to more types of thing if this parsing approach is used for things other 
                    // than numbers and single characters 
                    break;
                } 
            }
            if (sub.length == 0) {
                sub.type = DTSubStringType.End;
                return sub; 
            }
 
            return sub; 
        }
 
        internal void ConsumeSubString(DTSubString sub) {
            BCLDebug.Assert(sub.index == Index, "sub.index == Index");
            BCLDebug.Assert(sub.index + sub.length <= len, "sub.index + sub.length <= len");
            Index = sub.index + sub.length; 
            if (Index < len) {
                m_current = Value[Index]; 
            } 
        }
 

    }

    internal enum DTSubStringType { 
        Unknown = 0,
        Invalid = 1, 
        Number = 2, 
        End = 3,
        Other = 4, 
    }

    internal struct DTSubString {
        internal String s; 
        internal Int32 index;
        internal Int32 length; 
        internal DTSubStringType type; 
        internal Int32 value;
 
        internal Char this[Int32 relativeIndex] {
            get {
                return s[index + relativeIndex];
            } 
        }
    } 
 
    //
    // The buffer to store the parsing token. 
    //
    internal
    struct DateTimeToken {
        internal DateTimeParse.DTT dtt;    // Store the token 
        internal TokenType suffix; // Store the CJK Year/Month/Day suffix (if any)
        internal int num;    // Store the number that we are parsing (if any) 
    } 

    // 
    // The buffer to store temporary parsing information.
    //
    internal
    unsafe struct DateTimeRawInfo { 
        private  int* num;
        internal int numCount; 
        internal int month; 
        internal int year;
        internal int dayOfWeek; 
        internal int era;
        internal DateTimeParse.TM timeMark;
        internal double fraction;
        // 
        // <
 
 
        internal bool timeZone;
 
        internal void Init(int * numberBuffer) {
            month      = -1;
            year       = -1;
            dayOfWeek  = -1; 
            era        = -1;
            timeMark   = DateTimeParse.TM.NotSet; 
            fraction = -1; 
            num = numberBuffer;
        } 
        internal unsafe void AddNumber(int value) {
            num[numCount++] = value;
        }
        internal unsafe int GetNumber(int index) { 
            return num[index];
        } 
    } 

    internal enum ParseFailureKind { 
        None = 0,
        ArgumentNull = 1,
        Format = 2,
        FormatWithParameter = 3, 
        FormatBadDateTimeCalendar = 4,  // FormatException when ArgumentOutOfRange is thrown by a Calendar.TryToDateTime().
    }; 
 
    [Flags]
    internal enum ParseFlags { 
        HaveYear        = 0x00000001,
        HaveMonth       = 0x00000002,
        HaveDay         = 0x00000004,
        HaveHour        = 0x00000008, 
        HaveMinute      = 0x00000010,
        HaveSecond      = 0x00000020, 
        HaveTime        = 0x00000040, 
        HaveDate        = 0x00000080,
        TimeZoneUsed    = 0x00000100, 
        TimeZoneUtc     = 0x00000200,
        ParsedMonthName = 0x00000400,
        CaptureOffset   = 0x00000800,
        YearDefault     = 0x00001000, 
        Rfc1123Pattern  = 0x00002000,
        UtcSortPattern  = 0x00004000, 
    } 

    // 
    // This will store the result of the parsing.  And it will be eventually
    // used to construct a DateTime instance.
    //
    internal 
    struct DateTimeResult
    { 
        internal int Year; 
        internal int Month;
        internal int Day; 
        //
        // Set time defualt to 00:00:00.
        //
        internal int Hour; 
        internal int Minute;
        internal int Second; 
        internal double fraction; 

        internal int era; 

        internal ParseFlags flags;

        internal TimeSpan timeZoneOffset; 

        internal Calendar calendar; 
 
        internal DateTime parsedDate;
 
        internal ParseFailureKind failure;
        internal string failureMessageID;
        internal object failureMessageFormatArgument;
        internal string failureArgumentName; 

        internal void Init() { 
            Year    = -1; 
            Month   = -1;
            Day     = -1; 
            fraction = -1;
            era = -1;
        }
 
        internal void SetDate(int year, int month, int day)
        { 
            Year = year; 
            Month = month;
            Day = day; 
        }
        internal void SetFailure(ParseFailureKind failure, string failureMessageID, object failureMessageFormatArgument) {
            this.failure = failure;
            this.failureMessageID = failureMessageID; 
            this.failureMessageFormatArgument = failureMessageFormatArgument;
        } 
 
        internal void SetFailure(ParseFailureKind failure, string failureMessageID, object failureMessageFormatArgument, string failureArgumentName) {
            this.failure = failure; 
            this.failureMessageID = failureMessageID;
            this.failureMessageFormatArgument = failureMessageFormatArgument;
            this.failureArgumentName = failureArgumentName;
        } 

 
 

    } 

    // This is the helper data structure used in ParseExact().
    internal struct ParsingInfo {
 
        internal Calendar calendar;
        internal int dayOfWeek; 
        internal DateTimeParse.TM timeMark; 

        internal bool fUseHour12; 
        internal bool fUseTwoDigitYear;
        internal bool fAllowInnerWhite;
        internal bool fAllowTrailingWhite;
        internal bool fCustomNumberParser; 
        internal DateTimeParse.MatchNumberDelegate parseNumberDelegate;
 
        internal void Init() { 
            dayOfWeek = -1;
            timeMark = DateTimeParse.TM.NotSet; 
        }

    }
 
    //
    // The type of token that will be returned by DateTimeFormatInfo.Tokenize(). 
    // 
    internal enum TokenType {
        // The valid token should start from 1. 

        // Regular tokens. The range is from 0x00 ~ 0xff.
        NumberToken     = 1,    // The number.  E.g. "12"
        YearNumberToken = 2,    // The number which is considered as year number, which has 3 or more digits.  E.g. "2003" 
        Am              = 3,    // AM timemark. E.g. "AM"
        Pm              = 4,    // PM timemark. E.g. "PM" 
        MonthToken      = 5,    // A word (or words) that represents a month name.  E.g. "March" 
        EndOfString     = 6,    // End of string
        DayOfWeekToken  = 7,    // A word (or words) that represents a day of week name.  E.g. "Monday" or "Mon" 
        TimeZoneToken   = 8,    // A word that represents a timezone name. E.g. "GMT"
        EraToken        = 9,    // A word that represents a era name. E.g. "A.D."
        DateWordToken   = 10,   // A word that can appear in a DateTime string, but serves no parsing semantics.  E.g. "de" in Spanish culture.
        UnknownToken    = 11,   // An unknown word, which signals an error in parsing. 
        HebrewNumber    = 12,   // A number that is composed of Hebrew text.  Hebrew calendar uses Hebrew digits for year values, month values, and day values.
        JapaneseEraToken= 13,   // Era name for JapaneseCalendar 
/* SSS_WARNINGS_OFF */        TEraToken       = 14,   // Era name for TaiwanCalenadr /* SSS_WARNINGS_ON */ 
        IgnorableSymbol = 15,   // A separator like "," that is equivalent to whitespace
 

        // Separator tokens.
        SEP_Unk        = 0x100,         // Unknown separator.
        SEP_End        = 0x200,    // The end of the parsing string. 
        SEP_Space      = 0x300,    // Whitespace (including comma).
        SEP_Am         = 0x400,    // AM timemark. E.g. "AM" 
        SEP_Pm         = 0x500,    // PM timemark. E.g. "PM" 
        SEP_Date       = 0x600,    // date separator. E.g. "/"
        SEP_Time       = 0x700,    // time separator. E.g. ":" 
        SEP_YearSuff   = 0x800,    // Chinese/Japanese/Korean year suffix.
        SEP_MonthSuff  = 0x900,    // Chinese/Japanese/Korean month suffix.
        SEP_DaySuff    = 0xa00,    // Chinese/Japanese/Korean day suffix.
        SEP_HourSuff   = 0xb00,   // Chinese/Japanese/Korean hour suffix. 
        SEP_MinuteSuff = 0xc00,   // Chinese/Japanese/Korean minute suffix.
        SEP_SecondSuff = 0xd00,   // Chinese/Japanese/Korean second suffix. 
        SEP_LocalTimeMark = 0xe00,   // 'T', used in ISO 8601 format. 
        SEP_DateOrOffset = 0xf00,   // '-' which could be a date separator or start of a time zone offset
 
        RegularTokenMask = 0x00ff,
        SeparatorTokenMask = 0xff00,
    }
}
                        

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