SQLString.cs source code in C# .NET

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/ 4.0 / 4.0 / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / Data / System / Data / SQLTypes / SQLString.cs / 1305376 / SQLString.cs

                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
//  
// junfang 
// [....]
// [....] 
//----------------------------------------------------------------------------- 

//************************************************************************* 
// @File: SqlString.cs
//
// Create by:    JunFang
// 
// Purpose: Implementation of SqlString which is equivalent to
//            data type "nvarchar/varchar" in SQL Server 
// 
// Notes:
// 
// History:
//
//   09/30/99  JunFang    Created.
// 
// @EndHeader@
//************************************************************************* 
 
using System;
using System.Data.Common; 
using System.Globalization;
using System.Diagnostics;
using System.Runtime.InteropServices;
using System.Xml; 
using System.Xml.Schema;
using System.Xml.Serialization; 
 
namespace System.Data.SqlTypes {
    using System.Text; 
    using System.Configuration.Assemblies;

    // Options that are used in comparison
 	[Flags,Serializable] 
    public enum SqlCompareOptions {
        None            = 0x00000000, 
        IgnoreCase      = 0x00000001, 
        IgnoreNonSpace  = 0x00000002,
        IgnoreKanaType  = 0x00000008, // ignore kanatype 
        IgnoreWidth     = 0x00000010, // ignore width
        BinarySort      = 0x00008000, // binary sorting
        BinarySort2     = 0x00004000, // binary sorting 2
	} 

    ///  
    ///     
    ///       Represents a variable-length stream of characters to be stored in or retrieved from the database.
    ///     
    /// 
    [Serializable]
    [StructLayout(LayoutKind.Sequential)]
    [XmlSchemaProvider("GetXsdType")] 
    public struct SqlString : INullable, IComparable, IXmlSerializable {
        private String            m_value; 
        private CompareInfo       m_cmpInfo; 
        private int               m_lcid;     // Locale Id
        private SqlCompareOptions m_flag;     // Compare flags 
        private bool              m_fNotNull; // false if null

        /// 
        ///     
        ///       Represents a null value that can be assigned to the  property of an instance of
        ///       the  class. 
        ///     
        /// 
        public  static readonly SqlString Null = new SqlString(true); 

        internal static readonly UnicodeEncoding x_UnicodeEncoding = new UnicodeEncoding();

        ///  
        /// 
        public static readonly int IgnoreCase       = 0x1; 
        ///  
        /// 
        public static readonly int IgnoreWidth      = 0x10; 
        /// 
        /// 
        public static readonly int IgnoreNonSpace   = 0x2;
        ///  
        /// 
        public static readonly int IgnoreKanaType   = 0x8; 
        ///  
        /// 
        public static readonly int BinarySort       = 0x8000; 
        /// 
        /// 
        public static readonly int BinarySort2      = 0x4000;
 
        private static readonly SqlCompareOptions x_iDefaultFlag      =
                    SqlCompareOptions.IgnoreCase | SqlCompareOptions.IgnoreKanaType | 
                    SqlCompareOptions.IgnoreWidth; 
        private static readonly CompareOptions x_iValidCompareOptionMask    =
                    CompareOptions.IgnoreCase | CompareOptions.IgnoreWidth | 
                    CompareOptions.IgnoreNonSpace | CompareOptions.IgnoreKanaType;

        internal static readonly SqlCompareOptions x_iValidSqlCompareOptionMask    =
                    SqlCompareOptions.IgnoreCase | SqlCompareOptions.IgnoreWidth | 
                    SqlCompareOptions.IgnoreNonSpace | SqlCompareOptions.IgnoreKanaType |
                    SqlCompareOptions.BinarySort | SqlCompareOptions.BinarySort2; 
 
        internal static readonly int x_lcidUSEnglish    = 0x00000409;
        private  static readonly int x_lcidBinary       = 0x00008200; 


        // constructor
        // construct a Null 
        private SqlString(bool fNull) {
            m_value     = null; 
            m_cmpInfo   = null; 
            m_lcid      = 0;
            m_flag      = SqlCompareOptions.None; 
            m_fNotNull  = false;
        }

        // Constructor: Construct from both Unicode and NonUnicode data, according to fUnicode 
        /// 
        ///     
        ///       Initializes a new instance of the  class. 
        ///    
        ///  
        public SqlString(int lcid, SqlCompareOptions compareOptions, byte[] data, int index, int count, bool fUnicode) {
            m_lcid      = lcid;
            ValidateSqlCompareOptions(compareOptions);
            m_flag      = compareOptions; 
            if (data == null) {
                m_fNotNull  = false; 
                m_value     = null; 
                m_cmpInfo   = null;
            } 
            else {
                m_fNotNull  = true;

				// m_cmpInfo is set lazily, so that we don't need to pay the cost 
				// unless the string is used in comparison.
                m_cmpInfo   = null; 
 
                if (fUnicode) {
                    m_value = x_UnicodeEncoding.GetString(data, index, count); 
                }
                else {
                    CultureInfo culInfo = new CultureInfo(m_lcid);
                    Encoding cpe = System.Text.Encoding.GetEncoding(culInfo.TextInfo.ANSICodePage); 
                    m_value = cpe.GetString(data, index, count);
                } 
            } 
        }
 
        // Constructor: Construct from both Unicode and NonUnicode data, according to fUnicode
        /// 
        ///    
        ///       Initializes a new instance of the  class. 
        ///    
        ///  
        public SqlString(int lcid, SqlCompareOptions compareOptions, byte[] data, bool fUnicode) 
        : this(lcid, compareOptions, data, 0, data.Length, fUnicode) {
        } 

        /// 
        ///    
        ///       Initializes a new instance of the  class. 
        ///    
        ///  
        public SqlString(int lcid, SqlCompareOptions compareOptions, byte[] data, int index, int count) 
 			: this(lcid, compareOptions, data, index, count, true) {
        } 

        /// 
        ///    
        ///       Initializes a new instance of the  class. 
        ///    
        ///  
        public SqlString(int lcid, SqlCompareOptions compareOptions, byte[] data) 
			: this(lcid, compareOptions, data, 0, data.Length, true) {
        } 

/*
        //
 

 
 

 



 

 
 

 


*/
 
        /// 
        ///     
        ///       Initializes a new instance of the  class. 
        ///    
        ///  
        public SqlString(String data, int lcid, SqlCompareOptions compareOptions) {
            m_lcid      = lcid;
            ValidateSqlCompareOptions(compareOptions);
            m_flag      = compareOptions; 
            m_cmpInfo   = null;
            if (data == null) { 
                m_fNotNull  = false; 
                m_value     = null;
            } 
            else {
                m_fNotNull  = true;
                m_value     = data; // PERF: do not String.Copy
            } 
        }
 
        ///  
        ///    
        ///       Initializes a new instance of the  class. 
        ///    
        /// 
        public SqlString(String data, int lcid) : this(data, lcid, x_iDefaultFlag) {
        } 

        ///  
        ///     
        ///       Initializes a new instance of the  class.
        ///     
        /// 
        public SqlString(String data) : this(data, System.Globalization.CultureInfo.CurrentCulture.LCID, x_iDefaultFlag) {
        }
 
        private SqlString(int lcid, SqlCompareOptions compareOptions, String data, CompareInfo cmpInfo) {
            m_lcid      = lcid; 
            ValidateSqlCompareOptions(compareOptions); 
            m_flag      = compareOptions;
            if (data == null) { 
                m_fNotNull  = false;
                m_value     = null;
                m_cmpInfo   = null;
            } 
            else {
                m_value     = data; 
                m_cmpInfo   = cmpInfo; 
                m_fNotNull  = true;
            } 
        }


        // INullable 
        /// 
        ///     
        ///       Gets whether the  of the  is . 
        ///    
        ///  
        public bool IsNull {
            get { return !m_fNotNull;}
        }
 
        // property: Value
        ///  
        ///     
        ///       Gets the string that is to be stored.
        ///     
        /// 
        public String Value {
            get {
                if (!IsNull) 
                    return m_value;
                else 
                    throw new SqlNullValueException(); 
            }
        } 

        /// 
        ///    [To be supplied.]
        ///  
        public int LCID {
            get { 
                if (!IsNull) 
                    return m_lcid;
                else 
                    throw new SqlNullValueException();
            }
        }
 
        /// 
        ///    [To be supplied.] 
        ///  
        public CultureInfo CultureInfo {
            get { 
                if (!IsNull)
                    return CultureInfo.GetCultureInfo(m_lcid);
                else
                    throw new SqlNullValueException(); 
            }
        } 
 
        private void SetCompareInfo() {
 			SQLDebug.Check(!IsNull); 
 			if (m_cmpInfo == null)
				m_cmpInfo = (CultureInfo.GetCultureInfo(m_lcid)).CompareInfo;
 		}
 
        /// 
        ///    [To be supplied.] 
        ///  
        public CompareInfo CompareInfo {
            get { 
                if (!IsNull) {
					SetCompareInfo();
                    return m_cmpInfo;
				} 
                else
                    throw new SqlNullValueException(); 
            } 
        }
 
        /// 
        ///    [To be supplied.]
        /// 
        public SqlCompareOptions SqlCompareOptions { 
            get {
                if (!IsNull) 
                    return m_flag; 
                else
                    throw new SqlNullValueException(); 
            }
        }

        // Implicit conversion from String to SqlString 
        /// 
        ///    [To be supplied.] 
        ///  
        public static implicit operator SqlString(String x) {
            return new SqlString(x); 
        }

        // Explicit conversion from SqlString to String. Throw exception if x is Null.
        ///  
        ///    [To be supplied.]
        ///  
        public static explicit operator String(SqlString x) { 
            return x.Value;
        } 

        /// 
        ///    
        ///       Converts a  object to a string. 
        ///    
        ///  
        public override String ToString() { 
            return IsNull ? SQLResource.NullString : m_value;
        } 

        /// 
        ///    [To be supplied.]
        ///  
        public byte[] GetUnicodeBytes() {
            if (IsNull) 
                return null; 

            return x_UnicodeEncoding.GetBytes(m_value); 
        }

        /// 
        ///    [To be supplied.] 
        /// 
        public byte[] GetNonUnicodeBytes() { 
            if (IsNull) 
                return null;
 
            // Get the CultureInfo
            CultureInfo culInfo = new CultureInfo(m_lcid);

            Encoding cpe = System.Text.Encoding.GetEncoding(culInfo.TextInfo.ANSICodePage); 
            return cpe.GetBytes(m_value);
        } 
 
/*
        internal int GetSQLCID() { 
            if (IsNull)
                throw new SqlNullValueException();

            return MAKECID(m_lcid, m_flag); 
        }
*/ 
 
        // Binary operators
 
        // Concatenation
        /// 
        ///    [To be supplied.]
        ///  
        public static SqlString operator +(SqlString x, SqlString y) {
            if (x.IsNull || y.IsNull) 
                return SqlString.Null; 

            if (x.m_lcid != y.m_lcid || x.m_flag != y.m_flag) 
                throw new SqlTypeException(SQLResource.ConcatDiffCollationMessage);

            return new SqlString(x.m_lcid, x.m_flag, x.m_value + y.m_value,
					(x.m_cmpInfo == null) ? y.m_cmpInfo : x.m_cmpInfo); 
        }
 
        // StringCompare: Common compare function which is used by Compare and CompareTo 
        //  In the case of Compare (used by comparison operators) the int result needs to be converted to SqlBoolean type
        //  while CompareTo needs the result in int type 
        //  Pre-requisite: the null condition of the both string needs to be checked and handled by the caller of this function
        private static int StringCompare(SqlString x, SqlString y)
        {
            SQLDebug.Check(!x.IsNull && !y.IsNull, 
                           "!x.IsNull && !y.IsNull", "Null condition should be handled by the caller of StringCompare method");
 
            if (x.m_lcid != y.m_lcid || x.m_flag != y.m_flag) 
                throw new SqlTypeException(SQLResource.CompareDiffCollationMessage);
 
            x.SetCompareInfo();
            y.SetCompareInfo();
            SQLDebug.Check(x.FBinarySort() || (x.m_cmpInfo != null && y.m_cmpInfo != null),
                           "x.FBinarySort() || (x.m_cmpInfo != null && y.m_cmpInfo != null)", ""); 

            int iCmpResult; 
 
            if ((x.m_flag & SqlCompareOptions.BinarySort) != 0)
                iCmpResult = CompareBinary(x, y); 
            else if ((x.m_flag & SqlCompareOptions.BinarySort2) != 0)
                iCmpResult = CompareBinary2(x, y);
            else {
                // SqlString can be padded with spaces (Padding is turn on by default in SQL Server 2008 
                // Trim the trailing space for comparison
                //  Avoid using String.TrimEnd function to avoid extra string allocations 
 
                char[] rgchX = x.m_value.ToCharArray();
                char[] rgchY = y.m_value.ToCharArray(); 
                int cwchX = rgchX.Length;
                int cwchY = rgchY.Length;

                while (cwchX > 0 && rgchX[cwchX - 1] == ' ') 
                    cwchX --;
                while (cwchY > 0 && rgchY[cwchY - 1] == ' ') 
                    cwchY --; 

                CompareOptions options = CompareOptionsFromSqlCompareOptions(x.m_flag); 

                iCmpResult = x.m_cmpInfo.Compare(x.m_value, 0, cwchX, y.m_value, 0, cwchY, options);
            }
 
            return iCmpResult;
        } 
 
        // Comparison operators
        private static SqlBoolean Compare(SqlString x, SqlString y, EComparison ecExpectedResult) 
        {
            if (x.IsNull || y.IsNull)
                return SqlBoolean.Null;
 
            int iCmpResult = StringCompare(x, y);
 
            bool fResult = false; 

            switch (ecExpectedResult) { 
                case EComparison.EQ:
                    fResult = (iCmpResult == 0);
                    break;
 
                case EComparison.LT:
                    fResult = (iCmpResult < 0); 
                    break; 

                case EComparison.LE: 
                    fResult = (iCmpResult <= 0);
                    break;

                case EComparison.GT: 
                    fResult = (iCmpResult > 0);
                    break; 
 
                case EComparison.GE:
                    fResult = (iCmpResult >= 0); 
                    break;

                default:
                    SQLDebug.Check(false, "Invalid ecExpectedResult"); 
                    return SqlBoolean.Null;
            } 
 
            return new SqlBoolean(fResult);
        } 



        // Implicit conversions 

 
 
        // Explicit conversions
 
        // Explicit conversion from SqlBoolean to SqlString
        /// 
        ///    [To be supplied.]
        ///  
        public static explicit operator SqlString(SqlBoolean x) {
            return x.IsNull ? Null : new SqlString((x.Value).ToString()); 
        } 

        // Explicit conversion from SqlByte to SqlString 
        /// 
        ///    [To be supplied.]
        /// 
        public static explicit operator SqlString(SqlByte x) { 
            return x.IsNull ? Null : new SqlString((x.Value).ToString((IFormatProvider)null));
        } 
 
        // Explicit conversion from SqlInt16 to SqlString
        ///  
        ///    [To be supplied.]
        /// 
        public static explicit operator SqlString(SqlInt16 x) {
            return x.IsNull ? Null : new SqlString((x.Value).ToString((IFormatProvider)null)); 
        }
 
        // Explicit conversion from SqlInt32 to SqlString 
        /// 
        ///    [To be supplied.] 
        /// 
        public static explicit operator SqlString(SqlInt32 x) {
            return x.IsNull ? Null : new SqlString((x.Value).ToString((IFormatProvider)null));
        } 

        // Explicit conversion from SqlInt64 to SqlString 
        ///  
        ///    [To be supplied.]
        ///  
        public static explicit operator SqlString(SqlInt64 x) {
            return x.IsNull ? Null : new SqlString((x.Value).ToString((IFormatProvider)null));
        }
 
        // Explicit conversion from SqlSingle to SqlString
        ///  
        ///    [To be supplied.] 
        /// 
        public static explicit operator SqlString(SqlSingle x) { 
            return x.IsNull ? Null : new SqlString((x.Value).ToString((IFormatProvider)null));
        }

        // Explicit conversion from SqlDouble to SqlString 
        /// 
        ///    [To be supplied.] 
        ///  
        public static explicit operator SqlString(SqlDouble x) {
            return x.IsNull ? Null : new SqlString((x.Value).ToString((IFormatProvider)null)); 
        }

        // Explicit conversion from SqlDecimal to SqlString
        ///  
        ///    [To be supplied.]
        ///  
        public static explicit operator SqlString(SqlDecimal x) { 
            return x.IsNull ? Null : new SqlString(x.ToString());
        } 

        // Explicit conversion from SqlMoney to SqlString
        /// 
        ///    [To be supplied.] 
        /// 
        public static explicit operator SqlString(SqlMoney x) { 
            return x.IsNull ? Null : new SqlString(x.ToString()); 
        }
 
        // Explicit conversion from SqlDateTime to SqlString
        /// 
        ///    [To be supplied.]
        ///  
        public static explicit operator SqlString(SqlDateTime x) {
            return x.IsNull ? Null : new SqlString(x.ToString()); 
        } 

        // Explicit conversion from SqlGuid to SqlString 
        /// 
        ///    [To be supplied.]
        /// 
        public static explicit operator SqlString(SqlGuid x) { 
            return x.IsNull ? Null : new SqlString(x.ToString());
        } 
 
        /// 
        ///    [To be supplied.] 
        /// 
        public SqlString Clone() {
            if (IsNull)
                return new SqlString(true); 
            else {
                SqlString ret = new SqlString(m_value, m_lcid, m_flag); 
                return ret; 
            }
        } 

        // Overloading comparison operators
        /// 
        ///    [To be supplied.] 
        /// 
        public static SqlBoolean operator==(SqlString x, SqlString y) { 
            return Compare(x, y, EComparison.EQ); 
        }
 
        /// 
        ///    [To be supplied.]
        /// 
        public static SqlBoolean operator!=(SqlString x, SqlString y) { 
            return ! (x == y);
        } 
 
        /// 
        ///    [To be supplied.] 
        /// 
        public static SqlBoolean operator<(SqlString x, SqlString y) {
            return Compare(x, y, EComparison.LT);
        } 

        ///  
        ///    [To be supplied.] 
        /// 
        public static SqlBoolean operator>(SqlString x, SqlString y) { 
            return Compare(x, y, EComparison.GT);
        }

        ///  
        ///    [To be supplied.]
        ///  
        public static SqlBoolean operator<=(SqlString x, SqlString y) { 
            return Compare(x, y, EComparison.LE);
        } 

        /// 
        ///    [To be supplied.]
        ///  
        public static SqlBoolean operator>=(SqlString x, SqlString y) {
            return Compare(x, y, EComparison.GE); 
        } 

        //-------------------------------------------------- 
        // Alternative methods for overloaded operators
        //--------------------------------------------------

        // Alternative method for operator + 
        public static SqlString Concat(SqlString x, SqlString y) {
            return x + y; 
        } 

        public static SqlString Add(SqlString x, SqlString y) { 
            return x + y;
        }

        // Alternative method for operator == 
        public static SqlBoolean Equals(SqlString x, SqlString y) {
            return (x == y); 
        } 

        // Alternative method for operator != 
        public static SqlBoolean NotEquals(SqlString x, SqlString y) {
            return (x != y);
        }
 
        // Alternative method for operator <
        public static SqlBoolean LessThan(SqlString x, SqlString y) { 
            return (x < y); 
        }
 
        // Alternative method for operator >
        public static SqlBoolean GreaterThan(SqlString x, SqlString y) {
            return (x > y);
        } 

        // Alternative method for operator <= 
        public static SqlBoolean LessThanOrEqual(SqlString x, SqlString y) { 
            return (x <= y);
        } 

        // Alternative method for operator >=
        public static SqlBoolean GreaterThanOrEqual(SqlString x, SqlString y) {
            return (x >= y); 
        }
 
        // Alternative method for conversions. 

        public SqlBoolean ToSqlBoolean() { 
            return (SqlBoolean)this;
        }

        public SqlByte ToSqlByte() { 
            return (SqlByte)this;
        } 
 
        public SqlDateTime ToSqlDateTime() {
            return (SqlDateTime)this; 
        }

        public SqlDouble ToSqlDouble() {
            return (SqlDouble)this; 
        }
 
        public SqlInt16 ToSqlInt16() { 
            return (SqlInt16)this;
        } 

        public SqlInt32 ToSqlInt32() {
            return (SqlInt32)this;
        } 

        public SqlInt64 ToSqlInt64() { 
            return (SqlInt64)this; 
        }
 
        public SqlMoney ToSqlMoney() {
            return (SqlMoney)this;
        }
 
        public SqlDecimal ToSqlDecimal() {
            return (SqlDecimal)this; 
        } 

        public SqlSingle ToSqlSingle() { 
            return (SqlSingle)this;
        }

        public SqlGuid ToSqlGuid() { 
            return (SqlGuid)this;
        } 
 

 

        // Utility functions and constants

        private static void ValidateSqlCompareOptions(SqlCompareOptions compareOptions) { 
            if ((compareOptions & x_iValidSqlCompareOptionMask) != compareOptions)
                throw new ArgumentOutOfRangeException ("compareOptions"); 
        } 

        public static CompareOptions CompareOptionsFromSqlCompareOptions(SqlCompareOptions compareOptions) { 
            CompareOptions options = CompareOptions.None;

            ValidateSqlCompareOptions(compareOptions);
 
            if ((compareOptions & (SqlCompareOptions.BinarySort | SqlCompareOptions.BinarySort2)) != 0)
                throw ADP.ArgumentOutOfRange("compareOptions"); 
            else { 
                if ((compareOptions & SqlCompareOptions.IgnoreCase) != 0)
                    options |= CompareOptions.IgnoreCase; 
                if ((compareOptions & SqlCompareOptions.IgnoreNonSpace) != 0)
                    options |= CompareOptions.IgnoreNonSpace;
                if ((compareOptions & SqlCompareOptions.IgnoreKanaType) != 0)
                    options |= CompareOptions.IgnoreKanaType; 
                if ((compareOptions & SqlCompareOptions.IgnoreWidth) != 0)
                    options |= CompareOptions.IgnoreWidth; 
            } 

            return  options; 
        }

        /*
        private static SqlCompareOptions SqlCompareOptionsFromCompareOptions(CompareOptions compareOptions) { 
            SqlCompareOptions sqlOptions = SqlCompareOptions.None;
 
            if ((compareOptions & x_iValidCompareOptionMask) != compareOptions) 
                throw new ArgumentOutOfRangeException ("compareOptions");
            else { 
                if ((compareOptions & CompareOptions.IgnoreCase) != 0)
                    sqlOptions |= SqlCompareOptions.IgnoreCase;
                if ((compareOptions & CompareOptions.IgnoreNonSpace) != 0)
                    sqlOptions |= SqlCompareOptions.IgnoreNonSpace; 
                if ((compareOptions & CompareOptions.IgnoreKanaType) != 0)
                    sqlOptions |= SqlCompareOptions.IgnoreKanaType; 
                if ((compareOptions & CompareOptions.IgnoreWidth) != 0) 
                    sqlOptions |= SqlCompareOptions.IgnoreWidth;
            } 

            return  sqlOptions;
        }
        */ 

        private bool FBinarySort() { 
            return(!IsNull && (m_flag & (SqlCompareOptions.BinarySort | SqlCompareOptions.BinarySort2)) != 0); 
        }
 
        //    Wide-character string comparison for Binary Unicode Collation
        //    Return values:
        //        -1 : wstr1 < wstr2
        //        0  : wstr1 = wstr2 
        //        1  : wstr1 > wstr2
        // 
        //    Does a memory comparison. 
        private static int CompareBinary(SqlString x, SqlString y) {
            byte[] rgDataX = x_UnicodeEncoding.GetBytes(x.m_value); 
            byte[] rgDataY = x_UnicodeEncoding.GetBytes(y.m_value);
            int cbX = rgDataX.Length;
            int cbY = rgDataY.Length;
            int cbMin = cbX < cbY ? cbX : cbY; 
            int i;
 
            SQLDebug.Check(cbX % 2 == 0); 
            SQLDebug.Check(cbY % 2 == 0);
 
            for (i = 0; i < cbMin; i ++) {
                if (rgDataX[i] < rgDataY[i])
                    return -1;
                else if (rgDataX[i] > rgDataY[i]) 
                    return 1;
            } 
 
            i = cbMin;
 
            int iCh;
            int iSpace = (int)' ';

            if (cbX < cbY) { 
                for (; i < cbY; i += 2) {
                    iCh = ((int)rgDataY[i + 1]) << 8 + rgDataY[i]; 
                    if (iCh != iSpace) 
                        return (iSpace > iCh) ? 1 : -1;
                } 
            }
            else {
                for (; i < cbX; i += 2) {
                    iCh = ((int)rgDataX[i + 1]) << 8 + rgDataX[i]; 
                    if (iCh != iSpace)
                        return (iCh > iSpace) ? 1 : -1; 
                } 
            }
 
            return 0;
        }

        //    Wide-character string comparison for Binary2 Unicode Collation 
        //    Return values:
        //        -1 : wstr1 < wstr2 
        //        0  : wstr1 = wstr2 
        //        1  : wstr1 > wstr2
        // 
        //    Does a wchar comparison (different from memcmp of BinarySort).
        private static int CompareBinary2(SqlString x, SqlString y) {
            SQLDebug.Check(!x.IsNull && !y.IsNull);
 
            char[] rgDataX = x.m_value.ToCharArray();
            char[] rgDataY = y.m_value.ToCharArray(); 
            int cwchX = rgDataX.Length; 
            int cwchY = rgDataY.Length;
            int cwchMin = cwchX < cwchY ? cwchX : cwchY; 
            int i;

            for (i = 0; i < cwchMin; i ++) {
                if (rgDataX[i] < rgDataY[i]) 
                    return -1;
                else if (rgDataX[i] > rgDataY[i]) 
                    return 1; 
            }
 
            // If compares equal up to one of the string terminates,
            // pad it with spaces and compare with the rest of the other one.
            //
            char chSpace = ' '; 

            if (cwchX < cwchY) { 
                for (i = cwchMin; i < cwchY; i ++) { 
                    if (rgDataY[i] != chSpace)
                        return (chSpace > rgDataY[i]) ? 1 : -1; 
                }
            }
            else {
                for (i = cwchMin; i < cwchX; i ++) { 
                    if (rgDataX[i] != chSpace)
                        return (rgDataX[i] > chSpace) ? 1 : -1; 
                } 
            }
 
            return 0;
        }

/* 
        private void Print() {
            Debug.WriteLine("SqlString - "); 
            Debug.WriteLine("\tlcid = " + m_lcid.ToString()); 
            Debug.Write("\t");
            if ((m_flag & SqlCompareOptions.IgnoreCase) != 0) 
                Debug.Write("IgnoreCase, ");
            if ((m_flag & SqlCompareOptions.IgnoreNonSpace) != 0)
                Debug.Write("IgnoreNonSpace, ");
            if ((m_flag & SqlCompareOptions.IgnoreKanaType) != 0) 
                Debug.Write("IgnoreKanaType, ");
            if ((m_flag & SqlCompareOptions.IgnoreWidth) != 0) 
                Debug.Write("IgnoreWidth, "); 
            Debug.WriteLine("");
            Debug.WriteLine("\tvalue = " + m_value); 
            Debug.WriteLine("\tcmpinfo = " + m_cmpInfo);
        }
*/
        // IComparable 
        // Compares this object to another object, returning an integer that
        // indicates the relationship. 
        // Returns a value less than zero if this < object, zero if this = object, 
        // or a value greater than zero if this > object.
        // null is considered to be less than any instance. 
        // If object is not of same type, this method throws an ArgumentException.
        /// 
        ///    [To be supplied.]
        ///  
        public int CompareTo(Object value) {
            if (value is SqlString) { 
                SqlString i = (SqlString)value; 

                return CompareTo(i); 
            }
            throw ADP.WrongType(value.GetType(), typeof(SqlString));
        }
 
        public int CompareTo(SqlString value) {
            // If both Null, consider them equal. 
            // Otherwise, Null is less than anything. 
            if (IsNull)
                return value.IsNull ? 0  : -1; 
            else if (value.IsNull)
                return 1;

            int returnValue = StringCompare(this, value); 

            // Conver the result into -1, 0, or 1 as this method never returned any other values 
            //  This is to ensure the backcompat 
            if (returnValue < 0) {
                return -1; 
            }
            if (returnValue > 0) {
                return 1;
            } 

            return 0; 
        } 

        // Compares this instance with a specified object 
        /// 
        ///    [To be supplied.]
        /// 
        public override bool Equals(Object value) { 
            if (!(value is SqlString)) {
                return false; 
            } 

            SqlString i = (SqlString)value; 

            if (i.IsNull || IsNull)
                return (i.IsNull && IsNull);
            else 
                return (this == i).Value;
        } 
 
        // For hashing purpose
        ///  
        ///    [To be supplied.]
        /// 
        public override int GetHashCode() {
            if (IsNull) 
                return 0;
 
            byte[] rgbSortKey; 
            if (FBinarySort())
                rgbSortKey = x_UnicodeEncoding.GetBytes(m_value.TrimEnd()); 
            else
            {
                // VSDevDiv 479660
                //  GetHashCode should not throw just because this instance has an invalid LCID or compare options. 
                CompareInfo cmpInfo;
                CompareOptions options; 
                try { 
                    SetCompareInfo();
                    cmpInfo = m_cmpInfo; 
                    options = CompareOptionsFromSqlCompareOptions(m_flag);
                }
                catch (ArgumentException) {
                    // SetCompareInfo throws this when instance's LCID is unsupported 
                    // CompareOptionsFromSqlCompareOptions throws this when instance's options are invalid
                    cmpInfo = CultureInfo.InvariantCulture.CompareInfo; 
                    options = CompareOptions.None; 
                }
                rgbSortKey = cmpInfo.GetSortKey(m_value.TrimEnd(), options).KeyData; 
            }

            return SqlBinary.HashByteArray(rgbSortKey, rgbSortKey.Length);
        } 

        ///  
        ///    [To be supplied.] 
        /// 
        XmlSchema IXmlSerializable.GetSchema() { return null; } 

        /// 
        ///    [To be supplied.]
        ///  
        void IXmlSerializable.ReadXml(XmlReader reader) {
            string isNull = reader.GetAttribute("nil", XmlSchema.InstanceNamespace); 
            if (isNull != null && XmlConvert.ToBoolean(isNull)) { 
                // VSTFDevDiv# 479603 - SqlTypes read null value infinitely and never read the next value. Fix - Read the next value.
                reader.ReadElementString(); 
                m_fNotNull = false;
            }
            else {
                m_value = reader.ReadElementString(); 
                m_fNotNull = true;
            } 
        } 

        ///  
        ///    [To be supplied.]
        /// 
        void IXmlSerializable.WriteXml(XmlWriter writer) {
            if (IsNull) { 
                writer.WriteAttributeString("xsi", "nil", XmlSchema.InstanceNamespace, "true");
            } 
            else { 
                writer.WriteString(m_value);
            } 
        }

        /// 
        ///    [To be supplied.] 
        /// 
        public static XmlQualifiedName GetXsdType(XmlSchemaSet schemaSet) { 
            return new XmlQualifiedName("string", XmlSchema.Namespace); 
        }
 
    } // SqlString

/*
    internal struct SLocaleMapItem { 
        public int      lcid;           // the primary key, not nullable
        public String   name;           // unique, nullable 
        public int      idCodePage;     // the ANSI default code page of the locale 

        public SLocaleMapItem(int lid, String str, int cpid) { 
            lcid = lid;
            name = str;
            idCodePage = cpid;
        } 
    }
 
    // Struct to map lcid to ordinal 
    internal struct SLcidOrdMapItem {
        internal int    lcid; 
        internal int    uiOrd;
    };

    // Class to store map of lcids to ordinal 
    internal class CBuildLcidOrdMap {
        internal SLcidOrdMapItem[] m_rgLcidOrdMap; 
        internal int m_cValidLocales; 
        internal int m_uiPosEnglish; // Start binary searches here - this is index in array, not ordinal
 
        // Constructor builds the array sorted by lcid
        // We use a simple n**2 sort because the array is mostly sorted anyway
        // and objects of this class will be const, hence this will be called
        // only by VC compiler 
        public CBuildLcidOrdMap() {
            int i,j; 
 
            m_rgLcidOrdMap = new SLcidOrdMapItem[SqlString.x_cLocales];
 
            // Compact the array
            for (i=0,j=0; i < SqlString.x_cLocales; i++) {
                if (SqlString.x_rgLocaleMap[i].lcid != SqlString.x_lcidUnused) {
                    m_rgLcidOrdMap[j].lcid = SqlString.x_rgLocaleMap[i].lcid; 
                    m_rgLcidOrdMap[j].uiOrd = i;
                    j++; 
                } 
            }
 
            m_cValidLocales = j;

            // Set the rest to invalid
            while (j < SqlString.x_cLocales) { 
                m_rgLcidOrdMap[j].lcid = SqlString.x_lcidUnused;
                m_rgLcidOrdMap[j].uiOrd = 0; 
                j++; 
            }
 
            // Now sort in place
            // Algo:
            // Start from 1, assume list before i is sorted, if next item
            // violates this assumption, exchange with prev items until the 
            // item is in its correct place
            for (i=1; i0 && 
                    m_rgLcidOrdMap[j].lcid < m_rgLcidOrdMap[j-1].lcid; j--) {
                    // Swap with prev element 
                    int lcidTemp = m_rgLcidOrdMap[j-1].lcid;
                    int uiOrdTemp = m_rgLcidOrdMap[j-1].uiOrd;
                    m_rgLcidOrdMap[j-1].lcid = m_rgLcidOrdMap[j].lcid;
                    m_rgLcidOrdMap[j-1].uiOrd = m_rgLcidOrdMap[j].uiOrd; 
                    m_rgLcidOrdMap[j].lcid = lcidTemp;
                    m_rgLcidOrdMap[j].uiOrd = uiOrdTemp; 
                } 
            }
 
            // Set the position of the US_English LCID (Latin1_General)
            for (i=0; i
//     Copyright (c) Microsoft Corporation.  All rights reserved.
//  
// junfang 
// [....]
// [....] 
//----------------------------------------------------------------------------- 

//************************************************************************* 
// @File: SqlString.cs
//
// Create by:    JunFang
// 
// Purpose: Implementation of SqlString which is equivalent to
//            data type "nvarchar/varchar" in SQL Server 
// 
// Notes:
// 
// History:
//
//   09/30/99  JunFang    Created.
// 
// @EndHeader@
//************************************************************************* 
 
using System;
using System.Data.Common; 
using System.Globalization;
using System.Diagnostics;
using System.Runtime.InteropServices;
using System.Xml; 
using System.Xml.Schema;
using System.Xml.Serialization; 
 
namespace System.Data.SqlTypes {
    using System.Text; 
    using System.Configuration.Assemblies;

    // Options that are used in comparison
 	[Flags,Serializable] 
    public enum SqlCompareOptions {
        None            = 0x00000000, 
        IgnoreCase      = 0x00000001, 
        IgnoreNonSpace  = 0x00000002,
        IgnoreKanaType  = 0x00000008, // ignore kanatype 
        IgnoreWidth     = 0x00000010, // ignore width
        BinarySort      = 0x00008000, // binary sorting
        BinarySort2     = 0x00004000, // binary sorting 2
	} 

    ///  
    ///     
    ///       Represents a variable-length stream of characters to be stored in or retrieved from the database.
    ///     
    /// 
    [Serializable]
    [StructLayout(LayoutKind.Sequential)]
    [XmlSchemaProvider("GetXsdType")] 
    public struct SqlString : INullable, IComparable, IXmlSerializable {
        private String            m_value; 
        private CompareInfo       m_cmpInfo; 
        private int               m_lcid;     // Locale Id
        private SqlCompareOptions m_flag;     // Compare flags 
        private bool              m_fNotNull; // false if null

        /// 
        ///     
        ///       Represents a null value that can be assigned to the  property of an instance of
        ///       the  class. 
        ///     
        /// 
        public  static readonly SqlString Null = new SqlString(true); 

        internal static readonly UnicodeEncoding x_UnicodeEncoding = new UnicodeEncoding();

        ///  
        /// 
        public static readonly int IgnoreCase       = 0x1; 
        ///  
        /// 
        public static readonly int IgnoreWidth      = 0x10; 
        /// 
        /// 
        public static readonly int IgnoreNonSpace   = 0x2;
        ///  
        /// 
        public static readonly int IgnoreKanaType   = 0x8; 
        ///  
        /// 
        public static readonly int BinarySort       = 0x8000; 
        /// 
        /// 
        public static readonly int BinarySort2      = 0x4000;
 
        private static readonly SqlCompareOptions x_iDefaultFlag      =
                    SqlCompareOptions.IgnoreCase | SqlCompareOptions.IgnoreKanaType | 
                    SqlCompareOptions.IgnoreWidth; 
        private static readonly CompareOptions x_iValidCompareOptionMask    =
                    CompareOptions.IgnoreCase | CompareOptions.IgnoreWidth | 
                    CompareOptions.IgnoreNonSpace | CompareOptions.IgnoreKanaType;

        internal static readonly SqlCompareOptions x_iValidSqlCompareOptionMask    =
                    SqlCompareOptions.IgnoreCase | SqlCompareOptions.IgnoreWidth | 
                    SqlCompareOptions.IgnoreNonSpace | SqlCompareOptions.IgnoreKanaType |
                    SqlCompareOptions.BinarySort | SqlCompareOptions.BinarySort2; 
 
        internal static readonly int x_lcidUSEnglish    = 0x00000409;
        private  static readonly int x_lcidBinary       = 0x00008200; 


        // constructor
        // construct a Null 
        private SqlString(bool fNull) {
            m_value     = null; 
            m_cmpInfo   = null; 
            m_lcid      = 0;
            m_flag      = SqlCompareOptions.None; 
            m_fNotNull  = false;
        }

        // Constructor: Construct from both Unicode and NonUnicode data, according to fUnicode 
        /// 
        ///     
        ///       Initializes a new instance of the  class. 
        ///    
        ///  
        public SqlString(int lcid, SqlCompareOptions compareOptions, byte[] data, int index, int count, bool fUnicode) {
            m_lcid      = lcid;
            ValidateSqlCompareOptions(compareOptions);
            m_flag      = compareOptions; 
            if (data == null) {
                m_fNotNull  = false; 
                m_value     = null; 
                m_cmpInfo   = null;
            } 
            else {
                m_fNotNull  = true;

				// m_cmpInfo is set lazily, so that we don't need to pay the cost 
				// unless the string is used in comparison.
                m_cmpInfo   = null; 
 
                if (fUnicode) {
                    m_value = x_UnicodeEncoding.GetString(data, index, count); 
                }
                else {
                    CultureInfo culInfo = new CultureInfo(m_lcid);
                    Encoding cpe = System.Text.Encoding.GetEncoding(culInfo.TextInfo.ANSICodePage); 
                    m_value = cpe.GetString(data, index, count);
                } 
            } 
        }
 
        // Constructor: Construct from both Unicode and NonUnicode data, according to fUnicode
        /// 
        ///    
        ///       Initializes a new instance of the  class. 
        ///    
        ///  
        public SqlString(int lcid, SqlCompareOptions compareOptions, byte[] data, bool fUnicode) 
        : this(lcid, compareOptions, data, 0, data.Length, fUnicode) {
        } 

        /// 
        ///    
        ///       Initializes a new instance of the  class. 
        ///    
        ///  
        public SqlString(int lcid, SqlCompareOptions compareOptions, byte[] data, int index, int count) 
 			: this(lcid, compareOptions, data, index, count, true) {
        } 

        /// 
        ///    
        ///       Initializes a new instance of the  class. 
        ///    
        ///  
        public SqlString(int lcid, SqlCompareOptions compareOptions, byte[] data) 
			: this(lcid, compareOptions, data, 0, data.Length, true) {
        } 

/*
        //
 

 
 

 



 

 
 

 


*/
 
        /// 
        ///     
        ///       Initializes a new instance of the  class. 
        ///    
        ///  
        public SqlString(String data, int lcid, SqlCompareOptions compareOptions) {
            m_lcid      = lcid;
            ValidateSqlCompareOptions(compareOptions);
            m_flag      = compareOptions; 
            m_cmpInfo   = null;
            if (data == null) { 
                m_fNotNull  = false; 
                m_value     = null;
            } 
            else {
                m_fNotNull  = true;
                m_value     = data; // PERF: do not String.Copy
            } 
        }
 
        ///  
        ///    
        ///       Initializes a new instance of the  class. 
        ///    
        /// 
        public SqlString(String data, int lcid) : this(data, lcid, x_iDefaultFlag) {
        } 

        ///  
        ///     
        ///       Initializes a new instance of the  class.
        ///     
        /// 
        public SqlString(String data) : this(data, System.Globalization.CultureInfo.CurrentCulture.LCID, x_iDefaultFlag) {
        }
 
        private SqlString(int lcid, SqlCompareOptions compareOptions, String data, CompareInfo cmpInfo) {
            m_lcid      = lcid; 
            ValidateSqlCompareOptions(compareOptions); 
            m_flag      = compareOptions;
            if (data == null) { 
                m_fNotNull  = false;
                m_value     = null;
                m_cmpInfo   = null;
            } 
            else {
                m_value     = data; 
                m_cmpInfo   = cmpInfo; 
                m_fNotNull  = true;
            } 
        }


        // INullable 
        /// 
        ///     
        ///       Gets whether the  of the  is . 
        ///    
        ///  
        public bool IsNull {
            get { return !m_fNotNull;}
        }
 
        // property: Value
        ///  
        ///     
        ///       Gets the string that is to be stored.
        ///     
        /// 
        public String Value {
            get {
                if (!IsNull) 
                    return m_value;
                else 
                    throw new SqlNullValueException(); 
            }
        } 

        /// 
        ///    [To be supplied.]
        ///  
        public int LCID {
            get { 
                if (!IsNull) 
                    return m_lcid;
                else 
                    throw new SqlNullValueException();
            }
        }
 
        /// 
        ///    [To be supplied.] 
        ///  
        public CultureInfo CultureInfo {
            get { 
                if (!IsNull)
                    return CultureInfo.GetCultureInfo(m_lcid);
                else
                    throw new SqlNullValueException(); 
            }
        } 
 
        private void SetCompareInfo() {
 			SQLDebug.Check(!IsNull); 
 			if (m_cmpInfo == null)
				m_cmpInfo = (CultureInfo.GetCultureInfo(m_lcid)).CompareInfo;
 		}
 
        /// 
        ///    [To be supplied.] 
        ///  
        public CompareInfo CompareInfo {
            get { 
                if (!IsNull) {
					SetCompareInfo();
                    return m_cmpInfo;
				} 
                else
                    throw new SqlNullValueException(); 
            } 
        }
 
        /// 
        ///    [To be supplied.]
        /// 
        public SqlCompareOptions SqlCompareOptions { 
            get {
                if (!IsNull) 
                    return m_flag; 
                else
                    throw new SqlNullValueException(); 
            }
        }

        // Implicit conversion from String to SqlString 
        /// 
        ///    [To be supplied.] 
        ///  
        public static implicit operator SqlString(String x) {
            return new SqlString(x); 
        }

        // Explicit conversion from SqlString to String. Throw exception if x is Null.
        ///  
        ///    [To be supplied.]
        ///  
        public static explicit operator String(SqlString x) { 
            return x.Value;
        } 

        /// 
        ///    
        ///       Converts a  object to a string. 
        ///    
        ///  
        public override String ToString() { 
            return IsNull ? SQLResource.NullString : m_value;
        } 

        /// 
        ///    [To be supplied.]
        ///  
        public byte[] GetUnicodeBytes() {
            if (IsNull) 
                return null; 

            return x_UnicodeEncoding.GetBytes(m_value); 
        }

        /// 
        ///    [To be supplied.] 
        /// 
        public byte[] GetNonUnicodeBytes() { 
            if (IsNull) 
                return null;
 
            // Get the CultureInfo
            CultureInfo culInfo = new CultureInfo(m_lcid);

            Encoding cpe = System.Text.Encoding.GetEncoding(culInfo.TextInfo.ANSICodePage); 
            return cpe.GetBytes(m_value);
        } 
 
/*
        internal int GetSQLCID() { 
            if (IsNull)
                throw new SqlNullValueException();

            return MAKECID(m_lcid, m_flag); 
        }
*/ 
 
        // Binary operators
 
        // Concatenation
        /// 
        ///    [To be supplied.]
        ///  
        public static SqlString operator +(SqlString x, SqlString y) {
            if (x.IsNull || y.IsNull) 
                return SqlString.Null; 

            if (x.m_lcid != y.m_lcid || x.m_flag != y.m_flag) 
                throw new SqlTypeException(SQLResource.ConcatDiffCollationMessage);

            return new SqlString(x.m_lcid, x.m_flag, x.m_value + y.m_value,
					(x.m_cmpInfo == null) ? y.m_cmpInfo : x.m_cmpInfo); 
        }
 
        // StringCompare: Common compare function which is used by Compare and CompareTo 
        //  In the case of Compare (used by comparison operators) the int result needs to be converted to SqlBoolean type
        //  while CompareTo needs the result in int type 
        //  Pre-requisite: the null condition of the both string needs to be checked and handled by the caller of this function
        private static int StringCompare(SqlString x, SqlString y)
        {
            SQLDebug.Check(!x.IsNull && !y.IsNull, 
                           "!x.IsNull && !y.IsNull", "Null condition should be handled by the caller of StringCompare method");
 
            if (x.m_lcid != y.m_lcid || x.m_flag != y.m_flag) 
                throw new SqlTypeException(SQLResource.CompareDiffCollationMessage);
 
            x.SetCompareInfo();
            y.SetCompareInfo();
            SQLDebug.Check(x.FBinarySort() || (x.m_cmpInfo != null && y.m_cmpInfo != null),
                           "x.FBinarySort() || (x.m_cmpInfo != null && y.m_cmpInfo != null)", ""); 

            int iCmpResult; 
 
            if ((x.m_flag & SqlCompareOptions.BinarySort) != 0)
                iCmpResult = CompareBinary(x, y); 
            else if ((x.m_flag & SqlCompareOptions.BinarySort2) != 0)
                iCmpResult = CompareBinary2(x, y);
            else {
                // SqlString can be padded with spaces (Padding is turn on by default in SQL Server 2008 
                // Trim the trailing space for comparison
                //  Avoid using String.TrimEnd function to avoid extra string allocations 
 
                char[] rgchX = x.m_value.ToCharArray();
                char[] rgchY = y.m_value.ToCharArray(); 
                int cwchX = rgchX.Length;
                int cwchY = rgchY.Length;

                while (cwchX > 0 && rgchX[cwchX - 1] == ' ') 
                    cwchX --;
                while (cwchY > 0 && rgchY[cwchY - 1] == ' ') 
                    cwchY --; 

                CompareOptions options = CompareOptionsFromSqlCompareOptions(x.m_flag); 

                iCmpResult = x.m_cmpInfo.Compare(x.m_value, 0, cwchX, y.m_value, 0, cwchY, options);
            }
 
            return iCmpResult;
        } 
 
        // Comparison operators
        private static SqlBoolean Compare(SqlString x, SqlString y, EComparison ecExpectedResult) 
        {
            if (x.IsNull || y.IsNull)
                return SqlBoolean.Null;
 
            int iCmpResult = StringCompare(x, y);
 
            bool fResult = false; 

            switch (ecExpectedResult) { 
                case EComparison.EQ:
                    fResult = (iCmpResult == 0);
                    break;
 
                case EComparison.LT:
                    fResult = (iCmpResult < 0); 
                    break; 

                case EComparison.LE: 
                    fResult = (iCmpResult <= 0);
                    break;

                case EComparison.GT: 
                    fResult = (iCmpResult > 0);
                    break; 
 
                case EComparison.GE:
                    fResult = (iCmpResult >= 0); 
                    break;

                default:
                    SQLDebug.Check(false, "Invalid ecExpectedResult"); 
                    return SqlBoolean.Null;
            } 
 
            return new SqlBoolean(fResult);
        } 



        // Implicit conversions 

 
 
        // Explicit conversions
 
        // Explicit conversion from SqlBoolean to SqlString
        /// 
        ///    [To be supplied.]
        ///  
        public static explicit operator SqlString(SqlBoolean x) {
            return x.IsNull ? Null : new SqlString((x.Value).ToString()); 
        } 

        // Explicit conversion from SqlByte to SqlString 
        /// 
        ///    [To be supplied.]
        /// 
        public static explicit operator SqlString(SqlByte x) { 
            return x.IsNull ? Null : new SqlString((x.Value).ToString((IFormatProvider)null));
        } 
 
        // Explicit conversion from SqlInt16 to SqlString
        ///  
        ///    [To be supplied.]
        /// 
        public static explicit operator SqlString(SqlInt16 x) {
            return x.IsNull ? Null : new SqlString((x.Value).ToString((IFormatProvider)null)); 
        }
 
        // Explicit conversion from SqlInt32 to SqlString 
        /// 
        ///    [To be supplied.] 
        /// 
        public static explicit operator SqlString(SqlInt32 x) {
            return x.IsNull ? Null : new SqlString((x.Value).ToString((IFormatProvider)null));
        } 

        // Explicit conversion from SqlInt64 to SqlString 
        ///  
        ///    [To be supplied.]
        ///  
        public static explicit operator SqlString(SqlInt64 x) {
            return x.IsNull ? Null : new SqlString((x.Value).ToString((IFormatProvider)null));
        }
 
        // Explicit conversion from SqlSingle to SqlString
        ///  
        ///    [To be supplied.] 
        /// 
        public static explicit operator SqlString(SqlSingle x) { 
            return x.IsNull ? Null : new SqlString((x.Value).ToString((IFormatProvider)null));
        }

        // Explicit conversion from SqlDouble to SqlString 
        /// 
        ///    [To be supplied.] 
        ///  
        public static explicit operator SqlString(SqlDouble x) {
            return x.IsNull ? Null : new SqlString((x.Value).ToString((IFormatProvider)null)); 
        }

        // Explicit conversion from SqlDecimal to SqlString
        ///  
        ///    [To be supplied.]
        ///  
        public static explicit operator SqlString(SqlDecimal x) { 
            return x.IsNull ? Null : new SqlString(x.ToString());
        } 

        // Explicit conversion from SqlMoney to SqlString
        /// 
        ///    [To be supplied.] 
        /// 
        public static explicit operator SqlString(SqlMoney x) { 
            return x.IsNull ? Null : new SqlString(x.ToString()); 
        }
 
        // Explicit conversion from SqlDateTime to SqlString
        /// 
        ///    [To be supplied.]
        ///  
        public static explicit operator SqlString(SqlDateTime x) {
            return x.IsNull ? Null : new SqlString(x.ToString()); 
        } 

        // Explicit conversion from SqlGuid to SqlString 
        /// 
        ///    [To be supplied.]
        /// 
        public static explicit operator SqlString(SqlGuid x) { 
            return x.IsNull ? Null : new SqlString(x.ToString());
        } 
 
        /// 
        ///    [To be supplied.] 
        /// 
        public SqlString Clone() {
            if (IsNull)
                return new SqlString(true); 
            else {
                SqlString ret = new SqlString(m_value, m_lcid, m_flag); 
                return ret; 
            }
        } 

        // Overloading comparison operators
        /// 
        ///    [To be supplied.] 
        /// 
        public static SqlBoolean operator==(SqlString x, SqlString y) { 
            return Compare(x, y, EComparison.EQ); 
        }
 
        /// 
        ///    [To be supplied.]
        /// 
        public static SqlBoolean operator!=(SqlString x, SqlString y) { 
            return ! (x == y);
        } 
 
        /// 
        ///    [To be supplied.] 
        /// 
        public static SqlBoolean operator<(SqlString x, SqlString y) {
            return Compare(x, y, EComparison.LT);
        } 

        ///  
        ///    [To be supplied.] 
        /// 
        public static SqlBoolean operator>(SqlString x, SqlString y) { 
            return Compare(x, y, EComparison.GT);
        }

        ///  
        ///    [To be supplied.]
        ///  
        public static SqlBoolean operator<=(SqlString x, SqlString y) { 
            return Compare(x, y, EComparison.LE);
        } 

        /// 
        ///    [To be supplied.]
        ///  
        public static SqlBoolean operator>=(SqlString x, SqlString y) {
            return Compare(x, y, EComparison.GE); 
        } 

        //-------------------------------------------------- 
        // Alternative methods for overloaded operators
        //--------------------------------------------------

        // Alternative method for operator + 
        public static SqlString Concat(SqlString x, SqlString y) {
            return x + y; 
        } 

        public static SqlString Add(SqlString x, SqlString y) { 
            return x + y;
        }

        // Alternative method for operator == 
        public static SqlBoolean Equals(SqlString x, SqlString y) {
            return (x == y); 
        } 

        // Alternative method for operator != 
        public static SqlBoolean NotEquals(SqlString x, SqlString y) {
            return (x != y);
        }
 
        // Alternative method for operator <
        public static SqlBoolean LessThan(SqlString x, SqlString y) { 
            return (x < y); 
        }
 
        // Alternative method for operator >
        public static SqlBoolean GreaterThan(SqlString x, SqlString y) {
            return (x > y);
        } 

        // Alternative method for operator <= 
        public static SqlBoolean LessThanOrEqual(SqlString x, SqlString y) { 
            return (x <= y);
        } 

        // Alternative method for operator >=
        public static SqlBoolean GreaterThanOrEqual(SqlString x, SqlString y) {
            return (x >= y); 
        }
 
        // Alternative method for conversions. 

        public SqlBoolean ToSqlBoolean() { 
            return (SqlBoolean)this;
        }

        public SqlByte ToSqlByte() { 
            return (SqlByte)this;
        } 
 
        public SqlDateTime ToSqlDateTime() {
            return (SqlDateTime)this; 
        }

        public SqlDouble ToSqlDouble() {
            return (SqlDouble)this; 
        }
 
        public SqlInt16 ToSqlInt16() { 
            return (SqlInt16)this;
        } 

        public SqlInt32 ToSqlInt32() {
            return (SqlInt32)this;
        } 

        public SqlInt64 ToSqlInt64() { 
            return (SqlInt64)this; 
        }
 
        public SqlMoney ToSqlMoney() {
            return (SqlMoney)this;
        }
 
        public SqlDecimal ToSqlDecimal() {
            return (SqlDecimal)this; 
        } 

        public SqlSingle ToSqlSingle() { 
            return (SqlSingle)this;
        }

        public SqlGuid ToSqlGuid() { 
            return (SqlGuid)this;
        } 
 

 

        // Utility functions and constants

        private static void ValidateSqlCompareOptions(SqlCompareOptions compareOptions) { 
            if ((compareOptions & x_iValidSqlCompareOptionMask) != compareOptions)
                throw new ArgumentOutOfRangeException ("compareOptions"); 
        } 

        public static CompareOptions CompareOptionsFromSqlCompareOptions(SqlCompareOptions compareOptions) { 
            CompareOptions options = CompareOptions.None;

            ValidateSqlCompareOptions(compareOptions);
 
            if ((compareOptions & (SqlCompareOptions.BinarySort | SqlCompareOptions.BinarySort2)) != 0)
                throw ADP.ArgumentOutOfRange("compareOptions"); 
            else { 
                if ((compareOptions & SqlCompareOptions.IgnoreCase) != 0)
                    options |= CompareOptions.IgnoreCase; 
                if ((compareOptions & SqlCompareOptions.IgnoreNonSpace) != 0)
                    options |= CompareOptions.IgnoreNonSpace;
                if ((compareOptions & SqlCompareOptions.IgnoreKanaType) != 0)
                    options |= CompareOptions.IgnoreKanaType; 
                if ((compareOptions & SqlCompareOptions.IgnoreWidth) != 0)
                    options |= CompareOptions.IgnoreWidth; 
            } 

            return  options; 
        }

        /*
        private static SqlCompareOptions SqlCompareOptionsFromCompareOptions(CompareOptions compareOptions) { 
            SqlCompareOptions sqlOptions = SqlCompareOptions.None;
 
            if ((compareOptions & x_iValidCompareOptionMask) != compareOptions) 
                throw new ArgumentOutOfRangeException ("compareOptions");
            else { 
                if ((compareOptions & CompareOptions.IgnoreCase) != 0)
                    sqlOptions |= SqlCompareOptions.IgnoreCase;
                if ((compareOptions & CompareOptions.IgnoreNonSpace) != 0)
                    sqlOptions |= SqlCompareOptions.IgnoreNonSpace; 
                if ((compareOptions & CompareOptions.IgnoreKanaType) != 0)
                    sqlOptions |= SqlCompareOptions.IgnoreKanaType; 
                if ((compareOptions & CompareOptions.IgnoreWidth) != 0) 
                    sqlOptions |= SqlCompareOptions.IgnoreWidth;
            } 

            return  sqlOptions;
        }
        */ 

        private bool FBinarySort() { 
            return(!IsNull && (m_flag & (SqlCompareOptions.BinarySort | SqlCompareOptions.BinarySort2)) != 0); 
        }
 
        //    Wide-character string comparison for Binary Unicode Collation
        //    Return values:
        //        -1 : wstr1 < wstr2
        //        0  : wstr1 = wstr2 
        //        1  : wstr1 > wstr2
        // 
        //    Does a memory comparison. 
        private static int CompareBinary(SqlString x, SqlString y) {
            byte[] rgDataX = x_UnicodeEncoding.GetBytes(x.m_value); 
            byte[] rgDataY = x_UnicodeEncoding.GetBytes(y.m_value);
            int cbX = rgDataX.Length;
            int cbY = rgDataY.Length;
            int cbMin = cbX < cbY ? cbX : cbY; 
            int i;
 
            SQLDebug.Check(cbX % 2 == 0); 
            SQLDebug.Check(cbY % 2 == 0);
 
            for (i = 0; i < cbMin; i ++) {
                if (rgDataX[i] < rgDataY[i])
                    return -1;
                else if (rgDataX[i] > rgDataY[i]) 
                    return 1;
            } 
 
            i = cbMin;
 
            int iCh;
            int iSpace = (int)' ';

            if (cbX < cbY) { 
                for (; i < cbY; i += 2) {
                    iCh = ((int)rgDataY[i + 1]) << 8 + rgDataY[i]; 
                    if (iCh != iSpace) 
                        return (iSpace > iCh) ? 1 : -1;
                } 
            }
            else {
                for (; i < cbX; i += 2) {
                    iCh = ((int)rgDataX[i + 1]) << 8 + rgDataX[i]; 
                    if (iCh != iSpace)
                        return (iCh > iSpace) ? 1 : -1; 
                } 
            }
 
            return 0;
        }

        //    Wide-character string comparison for Binary2 Unicode Collation 
        //    Return values:
        //        -1 : wstr1 < wstr2 
        //        0  : wstr1 = wstr2 
        //        1  : wstr1 > wstr2
        // 
        //    Does a wchar comparison (different from memcmp of BinarySort).
        private static int CompareBinary2(SqlString x, SqlString y) {
            SQLDebug.Check(!x.IsNull && !y.IsNull);
 
            char[] rgDataX = x.m_value.ToCharArray();
            char[] rgDataY = y.m_value.ToCharArray(); 
            int cwchX = rgDataX.Length; 
            int cwchY = rgDataY.Length;
            int cwchMin = cwchX < cwchY ? cwchX : cwchY; 
            int i;

            for (i = 0; i < cwchMin; i ++) {
                if (rgDataX[i] < rgDataY[i]) 
                    return -1;
                else if (rgDataX[i] > rgDataY[i]) 
                    return 1; 
            }
 
            // If compares equal up to one of the string terminates,
            // pad it with spaces and compare with the rest of the other one.
            //
            char chSpace = ' '; 

            if (cwchX < cwchY) { 
                for (i = cwchMin; i < cwchY; i ++) { 
                    if (rgDataY[i] != chSpace)
                        return (chSpace > rgDataY[i]) ? 1 : -1; 
                }
            }
            else {
                for (i = cwchMin; i < cwchX; i ++) { 
                    if (rgDataX[i] != chSpace)
                        return (rgDataX[i] > chSpace) ? 1 : -1; 
                } 
            }
 
            return 0;
        }

/* 
        private void Print() {
            Debug.WriteLine("SqlString - "); 
            Debug.WriteLine("\tlcid = " + m_lcid.ToString()); 
            Debug.Write("\t");
            if ((m_flag & SqlCompareOptions.IgnoreCase) != 0) 
                Debug.Write("IgnoreCase, ");
            if ((m_flag & SqlCompareOptions.IgnoreNonSpace) != 0)
                Debug.Write("IgnoreNonSpace, ");
            if ((m_flag & SqlCompareOptions.IgnoreKanaType) != 0) 
                Debug.Write("IgnoreKanaType, ");
            if ((m_flag & SqlCompareOptions.IgnoreWidth) != 0) 
                Debug.Write("IgnoreWidth, "); 
            Debug.WriteLine("");
            Debug.WriteLine("\tvalue = " + m_value); 
            Debug.WriteLine("\tcmpinfo = " + m_cmpInfo);
        }
*/
        // IComparable 
        // Compares this object to another object, returning an integer that
        // indicates the relationship. 
        // Returns a value less than zero if this < object, zero if this = object, 
        // or a value greater than zero if this > object.
        // null is considered to be less than any instance. 
        // If object is not of same type, this method throws an ArgumentException.
        /// 
        ///    [To be supplied.]
        ///  
        public int CompareTo(Object value) {
            if (value is SqlString) { 
                SqlString i = (SqlString)value; 

                return CompareTo(i); 
            }
            throw ADP.WrongType(value.GetType(), typeof(SqlString));
        }
 
        public int CompareTo(SqlString value) {
            // If both Null, consider them equal. 
            // Otherwise, Null is less than anything. 
            if (IsNull)
                return value.IsNull ? 0  : -1; 
            else if (value.IsNull)
                return 1;

            int returnValue = StringCompare(this, value); 

            // Conver the result into -1, 0, or 1 as this method never returned any other values 
            //  This is to ensure the backcompat 
            if (returnValue < 0) {
                return -1; 
            }
            if (returnValue > 0) {
                return 1;
            } 

            return 0; 
        } 

        // Compares this instance with a specified object 
        /// 
        ///    [To be supplied.]
        /// 
        public override bool Equals(Object value) { 
            if (!(value is SqlString)) {
                return false; 
            } 

            SqlString i = (SqlString)value; 

            if (i.IsNull || IsNull)
                return (i.IsNull && IsNull);
            else 
                return (this == i).Value;
        } 
 
        // For hashing purpose
        ///  
        ///    [To be supplied.]
        /// 
        public override int GetHashCode() {
            if (IsNull) 
                return 0;
 
            byte[] rgbSortKey; 
            if (FBinarySort())
                rgbSortKey = x_UnicodeEncoding.GetBytes(m_value.TrimEnd()); 
            else
            {
                // VSDevDiv 479660
                //  GetHashCode should not throw just because this instance has an invalid LCID or compare options. 
                CompareInfo cmpInfo;
                CompareOptions options; 
                try { 
                    SetCompareInfo();
                    cmpInfo = m_cmpInfo; 
                    options = CompareOptionsFromSqlCompareOptions(m_flag);
                }
                catch (ArgumentException) {
                    // SetCompareInfo throws this when instance's LCID is unsupported 
                    // CompareOptionsFromSqlCompareOptions throws this when instance's options are invalid
                    cmpInfo = CultureInfo.InvariantCulture.CompareInfo; 
                    options = CompareOptions.None; 
                }
                rgbSortKey = cmpInfo.GetSortKey(m_value.TrimEnd(), options).KeyData; 
            }

            return SqlBinary.HashByteArray(rgbSortKey, rgbSortKey.Length);
        } 

        ///  
        ///    [To be supplied.] 
        /// 
        XmlSchema IXmlSerializable.GetSchema() { return null; } 

        /// 
        ///    [To be supplied.]
        ///  
        void IXmlSerializable.ReadXml(XmlReader reader) {
            string isNull = reader.GetAttribute("nil", XmlSchema.InstanceNamespace); 
            if (isNull != null && XmlConvert.ToBoolean(isNull)) { 
                // VSTFDevDiv# 479603 - SqlTypes read null value infinitely and never read the next value. Fix - Read the next value.
                reader.ReadElementString(); 
                m_fNotNull = false;
            }
            else {
                m_value = reader.ReadElementString(); 
                m_fNotNull = true;
            } 
        } 

        ///  
        ///    [To be supplied.]
        /// 
        void IXmlSerializable.WriteXml(XmlWriter writer) {
            if (IsNull) { 
                writer.WriteAttributeString("xsi", "nil", XmlSchema.InstanceNamespace, "true");
            } 
            else { 
                writer.WriteString(m_value);
            } 
        }

        /// 
        ///    [To be supplied.] 
        /// 
        public static XmlQualifiedName GetXsdType(XmlSchemaSet schemaSet) { 
            return new XmlQualifiedName("string", XmlSchema.Namespace); 
        }
 
    } // SqlString

/*
    internal struct SLocaleMapItem { 
        public int      lcid;           // the primary key, not nullable
        public String   name;           // unique, nullable 
        public int      idCodePage;     // the ANSI default code page of the locale 

        public SLocaleMapItem(int lid, String str, int cpid) { 
            lcid = lid;
            name = str;
            idCodePage = cpid;
        } 
    }
 
    // Struct to map lcid to ordinal 
    internal struct SLcidOrdMapItem {
        internal int    lcid; 
        internal int    uiOrd;
    };

    // Class to store map of lcids to ordinal 
    internal class CBuildLcidOrdMap {
        internal SLcidOrdMapItem[] m_rgLcidOrdMap; 
        internal int m_cValidLocales; 
        internal int m_uiPosEnglish; // Start binary searches here - this is index in array, not ordinal
 
        // Constructor builds the array sorted by lcid
        // We use a simple n**2 sort because the array is mostly sorted anyway
        // and objects of this class will be const, hence this will be called
        // only by VC compiler 
        public CBuildLcidOrdMap() {
            int i,j; 
 
            m_rgLcidOrdMap = new SLcidOrdMapItem[SqlString.x_cLocales];
 
            // Compact the array
            for (i=0,j=0; i < SqlString.x_cLocales; i++) {
                if (SqlString.x_rgLocaleMap[i].lcid != SqlString.x_lcidUnused) {
                    m_rgLcidOrdMap[j].lcid = SqlString.x_rgLocaleMap[i].lcid; 
                    m_rgLcidOrdMap[j].uiOrd = i;
                    j++; 
                } 
            }
 
            m_cValidLocales = j;

            // Set the rest to invalid
            while (j < SqlString.x_cLocales) { 
                m_rgLcidOrdMap[j].lcid = SqlString.x_lcidUnused;
                m_rgLcidOrdMap[j].uiOrd = 0; 
                j++; 
            }
 
            // Now sort in place
            // Algo:
            // Start from 1, assume list before i is sorted, if next item
            // violates this assumption, exchange with prev items until the 
            // item is in its correct place
            for (i=1; i0 && 
                    m_rgLcidOrdMap[j].lcid < m_rgLcidOrdMap[j-1].lcid; j--) {
                    // Swap with prev element 
                    int lcidTemp = m_rgLcidOrdMap[j-1].lcid;
                    int uiOrdTemp = m_rgLcidOrdMap[j-1].uiOrd;
                    m_rgLcidOrdMap[j-1].lcid = m_rgLcidOrdMap[j].lcid;
                    m_rgLcidOrdMap[j-1].uiOrd = m_rgLcidOrdMap[j].uiOrd; 
                    m_rgLcidOrdMap[j].lcid = lcidTemp;
                    m_rgLcidOrdMap[j].uiOrd = uiOrdTemp; 
                } 
            }
 
            // Set the position of the US_English LCID (Latin1_General)
            for (i=0; i

                        

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