//------------------------------------------------------------------------------
// <copyright file="XmlBinaryWriter.cs" company="Microsoft">
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// </copyright>
// <owner current="true" primary="true">[....]</owner>
//------------------------------------------------------------------------------

using System;
using System.Collections;
using System.IO;
using System.Text;
using System.Diagnostics;
using System.Globalization;

namespace System.Xml {
    // This is mostly just a copy of code in SqlTypes.SqlDecimal
    internal struct BinXmlSqlDecimal {
        internal byte m_bLen;
        internal byte m_bPrec;
        internal byte m_bScale;
        internal byte m_bSign;
        internal uint m_data1;
        internal uint m_data2;
        internal uint m_data3;
        internal uint m_data4;

        public bool IsPositive {
            get {
                return (m_bSign == 0);
            }
        }

        private static readonly byte NUMERIC_MAX_PRECISION = 38;            // Maximum precision of numeric
        private static readonly byte MaxPrecision = NUMERIC_MAX_PRECISION;  // max SS precision
        private static readonly byte MaxScale = NUMERIC_MAX_PRECISION;      // max SS scale

        private static readonly int x_cNumeMax = 4;
        private static readonly long x_lInt32Base = ((long)1) << 32;      // 2**32
        private static readonly ulong x_ulInt32Base = ((ulong)1) << 32;     // 2**32
        private static readonly ulong x_ulInt32BaseForMod = x_ulInt32Base - 1;    // 2**32 - 1 (0xFFF...FF)
        internal static readonly ulong x_llMax = Int64.MaxValue;   // Max of Int64
        //private static readonly uint x_ulBase10 = 10;
        private static readonly double DUINT_BASE = (double)x_lInt32Base;     // 2**32
        private static readonly double DUINT_BASE2 = DUINT_BASE * DUINT_BASE;  // 2**64
        private static readonly double DUINT_BASE3 = DUINT_BASE2 * DUINT_BASE; // 2**96
        //private static readonly double DMAX_NUME = 1.0e+38;                  // Max value of numeric
        //private static readonly uint DBL_DIG = 17;                       // Max decimal digits of double
        //private static readonly byte x_cNumeDivScaleMin = 6;     // Minimum result scale of numeric division
        // Array of multipliers for lAdjust and Ceiling/Floor.
        private static readonly uint[] x_rgulShiftBase = new uint[9] {
            10,
            10 * 10,
            10 * 10 * 10,
            10 * 10 * 10 * 10,
            10 * 10 * 10 * 10 * 10,
            10 * 10 * 10 * 10 * 10 * 10,
            10 * 10 * 10 * 10 * 10 * 10 * 10,
            10 * 10 * 10 * 10 * 10 * 10 * 10 * 10,
            10 * 10 * 10 * 10 * 10 * 10 * 10 * 10 * 10
        };

        public BinXmlSqlDecimal (byte[] data, int offset, bool trim) {
            byte b = data[offset];
            switch (b) {
                case 7: m_bLen = 1; break;
                case 11: m_bLen = 2; break;
                case 15: m_bLen = 3; break;
                case 19: m_bLen = 4; break;
                default: throw new XmlException(Res.XmlBinary_InvalidSqlDecimal, (string[])null);
            }
            m_bPrec = data[offset+1];
            m_bScale = data[offset+2];
            m_bSign = 0 == data[offset+3] ? (byte)1 : (byte)0;
            m_data1 = UIntFromByteArray(data, offset+4);
            m_data2 = (m_bLen > 1) ? UIntFromByteArray(data, offset+8) : 0;
            m_data3 = (m_bLen > 2) ? UIntFromByteArray(data, offset+12) : 0;
            m_data4 = (m_bLen > 3) ? UIntFromByteArray(data, offset+16) : 0;
            if (m_bLen == 4 && m_data4 == 0)
                m_bLen = 3;
            if (m_bLen == 3 && m_data3 == 0)
                m_bLen = 2;
            if (m_bLen == 2 && m_data2 == 0)
                m_bLen = 1;
            AssertValid();
            if (trim) {
                TrimTrailingZeros();
                AssertValid();
            }
        }

        public void Write(Stream strm) {
            strm.WriteByte((byte)(this.m_bLen * 4 + 3));
            strm.WriteByte(this.m_bPrec);
            strm.WriteByte(this.m_bScale);
            strm.WriteByte(0 == this.m_bSign ? (byte)1 : (byte)0);
            WriteUI4(this.m_data1, strm);
            if (this.m_bLen > 1) {
                WriteUI4(this.m_data2, strm);
                if (this.m_bLen > 2) {
                    WriteUI4(this.m_data3, strm);
                    if (this.m_bLen > 3) {
                        WriteUI4(this.m_data4, strm);
                    }
                }
            }
        }

        private void WriteUI4(uint val, Stream strm) {
            strm.WriteByte((byte)(val & 0xFF));
            strm.WriteByte((byte)((val >> 8) & 0xFF));
            strm.WriteByte((byte)((val >> 16) & 0xFF));
            strm.WriteByte((byte)((val >> 24) & 0xFF));
        }

        private static uint UIntFromByteArray(byte[] data, int offset) {
            int val = (data[offset]) << 0;
            val |= (data[offset+1]) << 8;
            val |= (data[offset+2]) << 16;
            val |= (data[offset+3]) << 24;
            return unchecked((uint)val);
        }

        // check whether is zero
        private bool FZero() {
            return (m_data1 == 0) && (m_bLen <= 1);
        }
        // Store data back from rguiData[] to m_data*
        private void StoreFromWorkingArray(uint[] rguiData) {
            Debug.Assert(rguiData.Length == 4);
            m_data1 = rguiData[0];
            m_data2 = rguiData[1];
            m_data3 = rguiData[2];
            m_data4 = rguiData[3];
        }

        // Find the case where we overflowed 10**38, but not 2**128
        private bool FGt10_38(uint[] rglData) {
            //Debug.Assert(rglData.Length == 4, "rglData.Length == 4", "Wrong array length: " + rglData.Length.ToString(CultureInfo.InvariantCulture));
            return rglData[3] >= 0x4b3b4ca8L && ((rglData[3] > 0x4b3b4ca8L) || (rglData[2] > 0x5a86c47aL) || (rglData[2] == 0x5a86c47aL) && (rglData[1] >= 0x098a2240L));
        }


        // Multi-precision one super-digit divide in place.
        // U = U / D,
        // R = U % D
        // Length of U can decrease
        private static void MpDiv1(uint[] rgulU,      // InOut| U
                                   ref int ciulU,      // InOut| # of digits in U
                                   uint iulD,       // In    | D
                                   out uint iulR        // Out    | R
                                   ) {
            Debug.Assert(rgulU.Length == x_cNumeMax);

            uint ulCarry = 0;
            ulong dwlAccum;
            ulong ulD = (ulong)iulD;
            int idU = ciulU;

            Debug.Assert(iulD != 0, "iulD != 0", "Divided by zero!");
            Debug.Assert(iulD > 0, "iulD > 0", "Invalid data: less than zero");
            Debug.Assert(ciulU > 0, "ciulU > 0", "No data in the array");
            while (idU > 0) {
                idU--;
                dwlAccum = (((ulong)ulCarry) << 32) + (ulong)(rgulU[idU]);
                rgulU[idU] = (uint)(dwlAccum / ulD);
                ulCarry = (uint)(dwlAccum - (ulong)rgulU[idU] * ulD);  // (ULONG) (dwlAccum % iulD)
            }

            iulR = ulCarry;
            MpNormalize(rgulU, ref ciulU);
        }
        // Normalize multi-precision number - remove leading zeroes
        private static void MpNormalize(uint[] rgulU,      // In   | Number
                                        ref int ciulU       // InOut| # of digits
                                        ) {
            while (ciulU > 1 && rgulU[ciulU - 1] == 0)
                ciulU--;
        }

        //    AdjustScale()
        //
        //    Adjust number of digits to the right of the decimal point.
        //    A positive adjustment increases the scale of the numeric value
        //    while a negative adjustment decreases the scale.  When decreasing
        //    the scale for the numeric value, the remainder is checked and
        //    rounded accordingly.
        //
        internal void AdjustScale(int digits, bool fRound) {
            uint ulRem;                  //Remainder when downshifting
            uint ulShiftBase;            //What to multiply by to effect scale adjust
            bool fNeedRound = false;     //Do we really need to round?
            byte bNewScale, bNewPrec;
            int lAdjust = digits;

            //If downshifting causes truncation of data
            if (lAdjust + m_bScale < 0)
                throw new XmlException(Res.SqlTypes_ArithTruncation, (string)null);

            //If uphifting causes scale overflow
            if (lAdjust + m_bScale > NUMERIC_MAX_PRECISION)
                throw new XmlException(Res.SqlTypes_ArithOverflow, (string)null);

            bNewScale = (byte)(lAdjust + m_bScale);
            bNewPrec = (byte)(Math.Min(NUMERIC_MAX_PRECISION, Math.Max(1, lAdjust + m_bPrec)));
            if (lAdjust > 0) {
                m_bScale = bNewScale;
                m_bPrec = bNewPrec;
                while (lAdjust > 0) {
                    //if lAdjust>=9, downshift by 10^9 each time, otherwise by the full amount
                    if (lAdjust >= 9) {
                        ulShiftBase = x_rgulShiftBase[8];
                        lAdjust -= 9;
                    }
                    else {
                        ulShiftBase = x_rgulShiftBase[lAdjust - 1];
                        lAdjust = 0;
                    }

                    MultByULong(ulShiftBase);
                }
            }
            else if (lAdjust < 0) {
                do {
                    if (lAdjust <= -9) {
                        ulShiftBase = x_rgulShiftBase[8];
                        lAdjust += 9;
                    }
                    else {
                        ulShiftBase = x_rgulShiftBase[-lAdjust - 1];
                        lAdjust = 0;
                    }

                    ulRem = DivByULong(ulShiftBase);
                } while (lAdjust < 0);

                // Do we really need to round?
                fNeedRound = (ulRem >= ulShiftBase / 2);
                m_bScale = bNewScale;
                m_bPrec = bNewPrec;
            }

            AssertValid();

            // After adjusting, if the result is 0 and remainder is less than 5,
            // set the sign to be positive and return.
            if (fNeedRound && fRound) {
                // If remainder is 5 or above, increment/decrement by 1.
                AddULong(1);
            }
            else if (FZero())
                this.m_bSign = 0;
        }
        //    AddULong()
        //
        //    Add ulAdd to this numeric.  The result will be returned in *this.
        //
        //    Parameters:
        //        this    - IN Operand1 & OUT Result
        //        ulAdd    - IN operand2.
        //
        private void AddULong(uint ulAdd) {
            ulong dwlAccum = (ulong)ulAdd;
            int iData;                  // which UI4 in this we are on
            int iDataMax = (int)m_bLen; // # of UI4s in this
            uint[] rguiData = new uint[4] { m_data1, m_data2, m_data3, m_data4 };

            // Add, starting at the LS UI4 until out of UI4s or no carry
            iData = 0;
            do {
                dwlAccum += (ulong)rguiData[iData];
                rguiData[iData] = (uint)dwlAccum;       // equivalent to mod x_dwlBaseUI4
                dwlAccum >>= 32;                        // equivalent to dwlAccum /= x_dwlBaseUI4;
                if (0 == dwlAccum) {
                    StoreFromWorkingArray(rguiData);
                    return;
                }

                iData++;
            } while (iData < iDataMax);

            // There is carry at the end
            Debug.Assert(dwlAccum < x_ulInt32Base, "dwlAccum < x_lInt32Base", "");

            // Either overflowed
            if (iData == x_cNumeMax)
                throw new XmlException(Res.SqlTypes_ArithOverflow, (string)null);

            // Or need to extend length by 1 UI4
            rguiData[iData] = (uint)dwlAccum;
            m_bLen++;
            if (FGt10_38(rguiData))
                throw new XmlException(Res.SqlTypes_ArithOverflow, (string)null);

            StoreFromWorkingArray(rguiData);
        }
        // multiply by a long integer
        private void MultByULong(uint uiMultiplier) {
            int iDataMax = m_bLen; // How many UI4s currently in *this
            ulong dwlAccum = 0;       // accumulated sum
            ulong dwlNextAccum = 0;   // accumulation past dwlAccum
            int iData;              // which UI4 in *This we are on.
            uint[] rguiData = new uint[4] { m_data1, m_data2, m_data3, m_data4 };

            for (iData = 0; iData < iDataMax; iData++) {
                Debug.Assert(dwlAccum < x_ulInt32Base);

                ulong ulTemp = (ulong)rguiData[iData];

                dwlNextAccum = ulTemp * (ulong)uiMultiplier;
                dwlAccum += dwlNextAccum;
                if (dwlAccum < dwlNextAccum)        // Overflow of int64 add
                    dwlNextAccum = x_ulInt32Base;   // how much to add to dwlAccum after div x_dwlBaseUI4
                    else
                    dwlNextAccum = 0;

                rguiData[iData] = (uint)dwlAccum;           // equivalent to mod x_dwlBaseUI4
                dwlAccum = (dwlAccum >> 32) + dwlNextAccum; // equivalent to div x_dwlBaseUI4
            }

            // If any carry,
            if (dwlAccum != 0) {
                // Either overflowed
                Debug.Assert(dwlAccum < x_ulInt32Base, "dwlAccum < x_dwlBaseUI4", "Integer overflow");
                if (iDataMax == x_cNumeMax)
                    throw new XmlException(Res.SqlTypes_ArithOverflow, (string)null);

                // Or extend length by one uint
                rguiData[iDataMax] = (uint)dwlAccum;
                m_bLen++;
            }

            if (FGt10_38(rguiData))
                throw new XmlException(Res.SqlTypes_ArithOverflow, (string)null);

            StoreFromWorkingArray(rguiData);
        }
        //    DivByULong()
        //
        //    Divide numeric value by a ULONG.  The result will be returned
        //    in the dividend *this.
        //
        //    Parameters:
        //        this        - IN Dividend & OUT Result
        //        ulDivisor    - IN Divisor
        //    Returns:        - OUT Remainder
        //
        internal uint DivByULong(uint iDivisor) {
            ulong dwlDivisor = (ulong)iDivisor;
            ulong dwlAccum = 0;           //Accumulated sum
            uint ulQuotientCur = 0;      // Value of the current UI4 of the quotient
            bool fAllZero = true;    // All of the quotient (so far) has been 0
            int iData;              //Which UI4 currently on

            // Check for zero divisor.
            if (dwlDivisor == 0)
                throw new XmlException(Res.SqlTypes_DivideByZero, (string)null);

            // Copy into array, so that we can iterate through the data
            uint[] rguiData = new uint[4] { m_data1, m_data2, m_data3, m_data4 };

            // Start from the MS UI4 of quotient, divide by divisor, placing result
            //        in quotient and carrying the remainder.
            //DEVNOTE DWORDLONG sufficient accumulator since:
            //        Accum < Divisor <= 2^32 - 1    at start each loop
            //                                    initially,and mod end previous loop
            //        Accum*2^32 < 2^64 - 2^32
            //                                    multiply both side by 2^32 (x_dwlBaseUI4)
            //        Accum*2^32 + m_rgulData < 2^64
            //                                    rglData < 2^32
            for (iData = m_bLen; iData > 0; iData--) {
                Debug.Assert(dwlAccum < dwlDivisor);
                dwlAccum = (dwlAccum << 32) + (ulong)(rguiData[iData - 1]); // dwlA*x_dwlBaseUI4 + rglData
                Debug.Assert((dwlAccum / dwlDivisor) < x_ulInt32Base);

                //Update dividend to the quotient.
                ulQuotientCur = (uint)(dwlAccum / dwlDivisor);
                rguiData[iData - 1] = ulQuotientCur;

                //Remainder to be carried to the next lower significant byte.
                dwlAccum = dwlAccum % dwlDivisor;

                // While current part of quotient still 0, reduce length
                fAllZero = fAllZero && (ulQuotientCur == 0);
                if (fAllZero)
                    m_bLen--;
            }

            StoreFromWorkingArray(rguiData);

            // If result is 0, preserve sign but set length to 5
            if (fAllZero)
                m_bLen = 1;

            AssertValid();

            // return the remainder
            Debug.Assert(dwlAccum < x_ulInt32Base);
            return (uint)dwlAccum;
        }

        //Determine the number of uints needed for a numeric given a precision
        //Precision        Length
        //    0            invalid
        //    1-9            1
        //    10-19        2
        //    20-28        3
        //    29-38        4
        // The array in Shiloh. Listed here for comparison.
        //private static readonly byte[] rgCLenFromPrec = new byte[] {5,5,5,5,5,5,5,5,5,9,9,9,9,9,
        //    9,9,9,9,9,13,13,13,13,13,13,13,13,13,17,17,17,17,17,17,17,17,17,17};
        private static readonly byte[] rgCLenFromPrec = new byte[] {
            1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4
        };
        private static byte CLenFromPrec(byte bPrec) {
            Debug.Assert(bPrec <= MaxPrecision && bPrec > 0, "bPrec <= MaxPrecision && bPrec > 0", "Invalid numeric precision");
            return rgCLenFromPrec[bPrec - 1];
        }

        private static char ChFromDigit(uint uiDigit) {
            Debug.Assert(uiDigit < 10);
            return (char)(uiDigit + '0');
        }

        public Decimal ToDecimal() {
            if ((int)m_data4 != 0 || m_bScale > 28)
                throw new XmlException(Res.SqlTypes_ArithOverflow, (string)null);

            return new Decimal((int)m_data1, (int)m_data2, (int)m_data3, !IsPositive, m_bScale);
        }

        void TrimTrailingZeros() {
            uint[]  rgulNumeric = new uint[4] { m_data1, m_data2, m_data3, m_data4};
            int     culLen = m_bLen;
            uint    ulRem; //Remainder of a division by x_ulBase10, i.e.,least significant digit

            // special-case 0
            if (culLen == 1 && rgulNumeric[0] == 0) {
                m_bScale = 0;
                return;
            }

            while (m_bScale > 0 && (culLen > 1 || rgulNumeric[0] != 0)) {
                MpDiv1 (rgulNumeric, ref culLen, 10, out ulRem);
                if ( ulRem == 0 ) {
                    m_data1 = rgulNumeric[0];
                    m_data2 = rgulNumeric[1];
                    m_data3 = rgulNumeric[2];
                    m_data4 = rgulNumeric[3];
                    m_bScale--;
                }
                else {
                    break;
                }
            }
            if (m_bLen == 4 && m_data4 == 0)
                m_bLen = 3;
            if (m_bLen == 3 && m_data3 == 0)
                m_bLen = 2;
            if (m_bLen == 2 && m_data2 == 0)
                m_bLen = 1;
        }

        public override String ToString() {
            AssertValid();

            // Make local copy of data to avoid modifying input.
            uint[]  rgulNumeric = new uint[4] { m_data1, m_data2, m_data3, m_data4};
            int     culLen = m_bLen;
            char[]  pszTmp = new char[NUMERIC_MAX_PRECISION + 1];   //Local Character buffer to hold
                                                                    //the decimal digits, from the
                                                                    //lowest significant to highest significant

            int     iDigits = 0;//Number of significant digits
            uint    ulRem; //Remainder of a division by x_ulBase10, i.e.,least significant digit

            // Build the final numeric string by inserting the sign, reversing
            // the order and inserting the decimal number at the correct position

            //Retrieve each digit from the lowest significant digit
            while (culLen > 1 || rgulNumeric[0] != 0) {
                MpDiv1 (rgulNumeric, ref culLen, 10, out ulRem);
                //modulo x_ulBase10 is the lowest significant digit
                pszTmp[iDigits++] = ChFromDigit(ulRem);
            }

            // if scale of the number has not been
            // reached pad remaining number with zeros.
            while (iDigits <= m_bScale) {
                pszTmp[iDigits++] = ChFromDigit(0);
            }

            bool fPositive = IsPositive;

            // Increment the result length if negative (need to add '-')
            int uiResultLen = fPositive ? iDigits : iDigits + 1;

            // Increment the result length if scale > 0 (need to add '.')
            if (m_bScale > 0)
                uiResultLen++;

            char[] szResult = new char[uiResultLen];
            int iCurChar = 0;

            if (!fPositive)
                szResult[iCurChar ++] = '-';

            while (iDigits > 0) {
                if (iDigits-- == m_bScale)
                    szResult[iCurChar ++] = '.';
                szResult[iCurChar ++] = pszTmp[iDigits];
            }

            AssertValid();

            return new String(szResult);
        }


        // Is this RE numeric valid?
        [System.Diagnostics.Conditional("DEBUG")]
        private void AssertValid() {
            // Scale,Prec in range
            Debug.Assert(m_bScale <= NUMERIC_MAX_PRECISION, "m_bScale <= NUMERIC_MAX_PRECISION", "In AssertValid");
            Debug.Assert(m_bScale <= m_bPrec, "m_bScale <= m_bPrec", "In AssertValid");
            Debug.Assert(m_bScale >= 0, "m_bScale >= 0", "In AssertValid");
            Debug.Assert(m_bPrec > 0, "m_bPrec > 0", "In AssertValid");
            Debug.Assert(CLenFromPrec(m_bPrec) >= m_bLen, "CLenFromPrec(m_bPrec) >= m_bLen", "In AssertValid");
            Debug.Assert(m_bLen <= x_cNumeMax, "m_bLen <= x_cNumeMax", "In AssertValid");

            uint[] rglData = new uint[4] { m_data1, m_data2, m_data3, m_data4 };

            // highest UI4 is non-0 unless value "zero"
            if (rglData[m_bLen - 1] == 0) {
                Debug.Assert(m_bLen == 1, "m_bLen == 1", "In AssertValid");
            }

            // All UI4s from length to end are 0
            for (int iulData = m_bLen; iulData < x_cNumeMax; iulData++)
                Debug.Assert(rglData[iulData] == 0, "rglData[iulData] == 0", "In AssertValid");
        }
    }

    internal struct BinXmlSqlMoney {
        long data;

        public BinXmlSqlMoney(int v) { this.data = v; }
        public BinXmlSqlMoney(long v) { this.data = v; }

        public Decimal ToDecimal() {
            bool neg;
            ulong v;
            if (this.data < 0) {
                neg = true;
                v = (ulong)unchecked(-this.data);
            }
            else {
                neg = false;
                v = (ulong)this.data;
            }
            // SQL Server stores money8 as ticks of 1/10000.
            const byte MoneyScale = 4;
            return new Decimal(unchecked((int)v), unchecked((int)(v >> 32)), 0, neg, MoneyScale);
        }

        public override String ToString() {
            Decimal money = ToDecimal();
            // Formatting of SqlMoney: At least two digits after decimal point
            return money.ToString("#0.00##", CultureInfo.InvariantCulture);
        }
    }

    internal abstract class BinXmlDateTime {
        
        const int MaxFractionDigits = 7;

        static internal int[] KatmaiTimeScaleMultiplicator = new int[8] {
            10000000,  
            1000000,  
            100000,  
            10000,  
            1000,  
            100,  
            10,  
            1,  
        };

        static void Write2Dig( StringBuilder sb, int val ) {
            Debug.Assert(val >= 0 && val < 100);
            sb.Append((char)('0' + (val/10)));
            sb.Append((char)('0' + (val%10)));
        }
        static void Write4DigNeg(StringBuilder sb, int val) {
            Debug.Assert(val > -10000 && val < 10000);
            if (val < 0) {
                val = -val;
                sb.Append('-');
            }
            Write2Dig(sb, val/100);
            Write2Dig(sb, val%100);
        }

        static void Write3Dec(StringBuilder sb, int val) {
            Debug.Assert(val >= 0 && val < 1000);
            int c3 = val % 10;
            val /= 10;
            int c2 = val % 10;
            val /= 10;
            int c1 = val;
            sb.Append('.');
            sb.Append((char)('0'+c1));
            sb.Append((char)('0'+c2));
            sb.Append((char)('0'+c3));
        }

        static void WriteDate(StringBuilder sb, int yr, int mnth, int day) {
            Write4DigNeg(sb, yr);
            sb.Append('-');
            Write2Dig(sb, mnth);
            sb.Append('-');
            Write2Dig(sb, day);
        }

        static void WriteTime(StringBuilder sb, int hr, int min, int sec, int ms) {
            Write2Dig(sb, hr);
            sb.Append(':');
            Write2Dig(sb, min);
            sb.Append(':');
            Write2Dig(sb, sec);
            if (ms != 0) {
                Write3Dec(sb, ms);
            }
        }

        static void WriteTimeFullPrecision(StringBuilder sb, int hr, int min, int sec, int fraction) {
            Write2Dig(sb, hr);
            sb.Append(':');
            Write2Dig(sb, min);
            sb.Append(':');
            Write2Dig(sb, sec);
            if (fraction != 0) {
                int fractionDigits = MaxFractionDigits;
                while (fraction % 10 == 0) {
                    fractionDigits --;
                    fraction /= 10;
                }
                char[] charArray = new char[fractionDigits];
                while(fractionDigits > 0) {
                    fractionDigits--;
                    charArray[fractionDigits] = (char)(fraction % 10 + '0');
                    fraction /= 10;
                }
                sb.Append('.');
                sb.Append(charArray);
            }
        }

        static void WriteTimeZone(StringBuilder sb, TimeSpan zone) {
            bool negTimeZone = true;
            if (zone.Ticks < 0) {
                negTimeZone = false;
                zone = zone.Negate();
            }
            WriteTimeZone(sb, negTimeZone, zone.Hours, zone.Minutes);
        }

        static void WriteTimeZone(StringBuilder sb, bool negTimeZone, int hr, int min) {
            if (hr == 0 && min == 0) {
                sb.Append('Z');
            }
            else {
                sb.Append(negTimeZone ? '+' : '-');
                Write2Dig(sb, hr);
                sb.Append(':');
                Write2Dig(sb, min);
            }
        }

        static void BreakDownXsdDateTime(long val, out int yr, out int mnth, out int day, out int hr, out int min, out int sec, out int ms) {
            if (val < 0)
                goto Error;
            long date = val / 4; // trim indicator bits
            ms = (int)(date % 1000);
            date /= 1000;
            sec = (int)(date % 60);
            date /= 60;
            min = (int)(date % 60);
            date /= 60;
            hr = (int)(date % 24);
            date /= 24;
            day = (int)(date % 31) + 1;
            date /= 31;
            mnth = (int)(date % 12) + 1;
            date /= 12;
            yr = (int)(date - 9999);
            if (yr < -9999 || yr > 9999)
                goto Error;
            return;
        Error:
            throw new XmlException(Res.SqlTypes_ArithOverflow, (string)null);
        }

        static void BreakDownXsdDate(long val, out int yr, out int mnth, out int day, out bool negTimeZone, out int hr, out int min) {
            if (val < 0)
                goto Error;
            val = val / 4; // trim indicator bits
            int totalMin = (int)(val % (29*60)) - 60*14;
            long totalDays = val / (29*60);

            if (negTimeZone = (totalMin < 0))
                totalMin = -totalMin;

            min = totalMin % 60;
            hr = totalMin / 60;

            day = (int)(totalDays % 31) + 1;
            totalDays /= 31;
            mnth = (int)(totalDays % 12) + 1;
            yr = (int)(totalDays / 12) - 9999;
            if (yr < -9999 || yr > 9999)
                goto Error;
            return;
        Error:
            throw new XmlException(Res.SqlTypes_ArithOverflow, (string)null);
        }

        static void BreakDownXsdTime(long val, out int hr, out int min, out int sec, out int ms) {
            if (val < 0)
                goto Error;
            val = val / 4; // trim indicator bits
            ms = (int)(val % 1000);
            val /= 1000;
            sec = (int)(val % 60);
            val /= 60;
            min = (int)(val % 60);
            hr = (int)(val / 60);
            if (0 > hr || hr > 23)
                goto Error;
            return;
        Error:
            throw new XmlException(Res.SqlTypes_ArithOverflow, (string)null);
        }

        public static string XsdDateTimeToString(long val) {
            int yr; int mnth; int day; int hr; int min; int sec; int ms;
            BreakDownXsdDateTime(val, out yr, out mnth, out day, out hr, out min, out sec, out ms);
            StringBuilder sb = new StringBuilder(20);
            WriteDate(sb, yr, mnth, day);
            sb.Append('T');
            WriteTime(sb, hr, min, sec, ms);
            sb.Append('Z');
            return sb.ToString();
        }
        public static DateTime XsdDateTimeToDateTime(long val) {
            int yr; int mnth; int day; int hr; int min; int sec; int ms;
            BreakDownXsdDateTime(val, out yr, out mnth, out day, out hr, out min, out sec, out ms);
            return new DateTime(yr, mnth, day, hr, min, sec, ms, DateTimeKind.Utc);
        }

        public static string XsdDateToString(long val) {
            int yr; int mnth; int day; int hr; int min; bool negTimeZ;
            BreakDownXsdDate(val, out yr, out mnth, out day, out negTimeZ, out hr, out min);
            StringBuilder sb = new StringBuilder(20);
            WriteDate(sb, yr, mnth, day);
            WriteTimeZone(sb, negTimeZ, hr, min);
            return sb.ToString();
        }
        public static DateTime XsdDateToDateTime(long val) {
            int yr; int mnth; int day; int hr; int min; bool negTimeZ;
            BreakDownXsdDate(val, out yr, out mnth, out day, out negTimeZ, out hr, out min);
            DateTime d = new DateTime(yr, mnth, day, 0, 0, 0, DateTimeKind.Utc);
            // adjust for timezone
            int adj = (negTimeZ ? -1 : 1) * ( (hr * 60) + min );
            return TimeZone.CurrentTimeZone.ToLocalTime( d.AddMinutes(adj) );
        }

        public static string XsdTimeToString(long val) {
            int hr; int min; int sec; int ms;
            BreakDownXsdTime(val, out hr, out min, out sec, out ms);
            StringBuilder sb = new StringBuilder(16);
            WriteTime(sb, hr, min, sec, ms);
            sb.Append('Z');
            return sb.ToString();
        }
        public static DateTime XsdTimeToDateTime(long val) {
            int hr; int min; int sec; int ms;
            BreakDownXsdTime(val, out hr, out min, out sec, out ms);
            return new DateTime(1, 1, 1, hr, min, sec, ms, DateTimeKind.Utc);
        }

        public static string SqlDateTimeToString(int dateticks, uint timeticks) {
            DateTime dateTime = SqlDateTimeToDateTime(dateticks, timeticks);
            string format = (dateTime.Millisecond != 0) ? "yyyy/MM/dd\\THH:mm:ss.ffff" : "yyyy/MM/dd\\THH:mm:ss";
            return dateTime.ToString(format, CultureInfo.InvariantCulture);
        }
        public static DateTime SqlDateTimeToDateTime(int dateticks, uint timeticks) {
            DateTime SQLBaseDate = new DateTime(1900, 1, 1);
            //long millisecond = (long)(((ulong)timeticks * 20 + (ulong)3) / (ulong)6);
            long millisecond = (long)(timeticks / SQLTicksPerMillisecond + 0.5);
            return SQLBaseDate.Add( new TimeSpan( dateticks * TimeSpan.TicksPerDay +
                                                  millisecond * TimeSpan.TicksPerMillisecond ) );
        }

        // Number of (100ns) ticks per time unit
        private static readonly double SQLTicksPerMillisecond = 0.3;
        public static readonly int SQLTicksPerSecond = 300;
        public static readonly int SQLTicksPerMinute = SQLTicksPerSecond * 60;
        public static readonly int SQLTicksPerHour = SQLTicksPerMinute * 60;
        private static readonly int SQLTicksPerDay = SQLTicksPerHour * 24;


        public static string SqlSmallDateTimeToString(short dateticks, ushort timeticks) {
            DateTime dateTime = SqlSmallDateTimeToDateTime(dateticks, timeticks);
            return dateTime.ToString("yyyy/MM/dd\\THH:mm:ss", CultureInfo.InvariantCulture);
        }
        public static DateTime SqlSmallDateTimeToDateTime(short dateticks, ushort timeticks) {
            return SqlDateTimeToDateTime( (int)dateticks, (uint)(timeticks * SQLTicksPerMinute) );
        }

        // Conversions of the Katmai date & time types to DateTime
        public static DateTime XsdKatmaiDateToDateTime(byte[] data, int offset) {
            // Katmai SQL type "DATE"
            long dateTicks = GetKatmaiDateTicks(data, ref offset);
            DateTime dt = new DateTime(dateTicks);
            return dt;
        }

        public static DateTime XsdKatmaiDateTimeToDateTime(byte[] data, int offset) {
            // Katmai SQL type "DATETIME2"
            long timeTicks = GetKatmaiTimeTicks(data, ref offset);
            long dateTicks = GetKatmaiDateTicks(data, ref offset);
            DateTime dt = new DateTime(dateTicks + timeTicks);
            return dt;
        }

        public static DateTime XsdKatmaiTimeToDateTime(byte[] data, int offset) {
            // TIME without zone is stored as DATETIME2
            return XsdKatmaiDateTimeToDateTime(data, offset);
        }

        public static DateTime XsdKatmaiDateOffsetToDateTime( byte[] data, int offset ) {
            // read the timezoned value into DateTimeOffset and then convert to local time
            return XsdKatmaiDateOffsetToDateTimeOffset(data, offset).LocalDateTime;
        }

        public static DateTime XsdKatmaiDateTimeOffsetToDateTime(byte[] data, int offset) {
            // read the timezoned value into DateTimeOffset and then convert to local time
            return XsdKatmaiDateTimeOffsetToDateTimeOffset(data, offset).LocalDateTime;
        }
        
        public static DateTime XsdKatmaiTimeOffsetToDateTime(byte[] data, int offset) {
            // read the timezoned value into DateTimeOffset and then convert to local time
            return XsdKatmaiTimeOffsetToDateTimeOffset(data, offset).LocalDateTime;
        }

        // Conversions of the Katmai date & time types to DateTimeOffset
        public static DateTimeOffset XsdKatmaiDateToDateTimeOffset( byte[] data, int offset ) {
            // read the value into DateTime and then convert it to DateTimeOffset, which adds local time zone
            return (DateTimeOffset)XsdKatmaiDateToDateTime(data, offset);
        }

        public static DateTimeOffset XsdKatmaiDateTimeToDateTimeOffset(byte[] data, int offset) {
            // read the value into DateTime and then convert it to DateTimeOffset, which adds local time zone
            return (DateTimeOffset)XsdKatmaiDateTimeToDateTime(data, offset);
        }

        public static DateTimeOffset XsdKatmaiTimeToDateTimeOffset(byte[] data, int offset) {
            // read the value into DateTime and then convert it to DateTimeOffset, which adds local time zone
            return (DateTimeOffset)XsdKatmaiTimeToDateTime(data, offset);
        }

        public static DateTimeOffset XsdKatmaiDateOffsetToDateTimeOffset(byte[] data, int offset) {
            // DATE with zone is stored as DATETIMEOFFSET
            return XsdKatmaiDateTimeOffsetToDateTimeOffset(data, offset);
        }

        public static DateTimeOffset XsdKatmaiDateTimeOffsetToDateTimeOffset(byte[] data, int offset) {
            // Katmai SQL type "DATETIMEOFFSET"
            long timeTicks = GetKatmaiTimeTicks(data, ref offset);
            long dateTicks = GetKatmaiDateTicks(data, ref offset);
            long zoneTicks = GetKatmaiTimeZoneTicks(data, offset);
            // The DATETIMEOFFSET values are serialized in UTC, but DateTimeOffset takes adjusted time -> we need to add zoneTicks
            DateTimeOffset dto = new DateTimeOffset(dateTicks + timeTicks + zoneTicks, new TimeSpan(zoneTicks));
            return dto;
        }

        public static DateTimeOffset XsdKatmaiTimeOffsetToDateTimeOffset(byte[] data, int offset) {
            // TIME with zone is stored as DATETIMEOFFSET
            return XsdKatmaiDateTimeOffsetToDateTimeOffset(data, offset);
        }

        // Conversions of the Katmai date & time types to string
        public static string XsdKatmaiDateToString(byte[] data, int offset) {
            DateTime dt = XsdKatmaiDateToDateTime(data, offset);
            StringBuilder sb = new StringBuilder(10);
            WriteDate(sb, dt.Year, dt.Month, dt.Day);
            return sb.ToString();
        }

        public static string XsdKatmaiDateTimeToString(byte[] data, int offset) {
            DateTime dt = XsdKatmaiDateTimeToDateTime(data, offset);
            StringBuilder sb = new StringBuilder(33);
            WriteDate(sb, dt.Year, dt.Month, dt.Day);
            sb.Append('T');
            WriteTimeFullPrecision(sb, dt.Hour, dt.Minute, dt.Second, GetFractions(dt));
            return sb.ToString();
        }

        public static string XsdKatmaiTimeToString(byte[] data, int offset) {
            DateTime dt = XsdKatmaiTimeToDateTime(data, offset);
            StringBuilder sb = new StringBuilder(16);
            WriteTimeFullPrecision(sb, dt.Hour, dt.Minute, dt.Second, GetFractions(dt));
            return sb.ToString();
        }

        public static string XsdKatmaiDateOffsetToString(byte[] data, int offset) {
            DateTimeOffset dto = XsdKatmaiDateOffsetToDateTimeOffset(data, offset);
            StringBuilder sb = new StringBuilder(16);
            WriteDate(sb, dto.Year, dto.Month, dto.Day);
            WriteTimeZone(sb, dto.Offset);
            return sb.ToString();
        }

        public static string XsdKatmaiDateTimeOffsetToString(byte[] data, int offset) {
            DateTimeOffset dto = XsdKatmaiDateTimeOffsetToDateTimeOffset(data, offset);
            StringBuilder sb = new StringBuilder(39);
            WriteDate(sb, dto.Year, dto.Month, dto.Day);
            sb.Append('T');
            WriteTimeFullPrecision(sb, dto.Hour, dto.Minute, dto.Second, GetFractions(dto));
            WriteTimeZone(sb, dto.Offset);
            return sb.ToString();
        }

        public static string XsdKatmaiTimeOffsetToString(byte[] data, int offset) {
            DateTimeOffset dto = XsdKatmaiTimeOffsetToDateTimeOffset(data, offset);
            StringBuilder sb = new StringBuilder(22);
            WriteTimeFullPrecision(sb, dto.Hour, dto.Minute, dto.Second, GetFractions(dto));
            WriteTimeZone(sb, dto.Offset);
            return sb.ToString();
        }

        // Helper methods for the Katmai date & time types
        static long GetKatmaiDateTicks(byte[] data, ref int pos) {
            int p = pos;
            pos = p + 3;
            return (data[p] | data[p + 1] << 8 | data[p + 2] << 16) * TimeSpan.TicksPerDay;
        }
        
        static long GetKatmaiTimeTicks(byte[] data, ref int pos) {
            int p = pos;
            byte scale = data[p];
            long timeTicks;
            p++;
            if (scale <= 2) {
                timeTicks = data[p] | (data[p + 1] << 8) | (data[p + 2] << 16);
                pos = p + 3;
            }
            else if (scale <= 4) {
                timeTicks = data[p] | (data[p + 1] << 8) | (data[p + 2] << 16);
                timeTicks |= ((long)data[p + 3] << 24);
                pos = p + 4;
            }
            else if (scale <= 7) {
                timeTicks = data[p] | (data[p + 1] << 8) | (data[p + 2] << 16);
                timeTicks |= ((long)data[p + 3] << 24) | ((long)data[p + 4] << 32);
                pos = p + 5;
            }
            else {
                throw new XmlException(Res.SqlTypes_ArithOverflow, (string)null);
            }
            return timeTicks * KatmaiTimeScaleMultiplicator[scale];
        }

        static long GetKatmaiTimeZoneTicks(byte[] data, int pos) {
            return (short)(data[pos] | data[pos + 1] << 8) * TimeSpan.TicksPerMinute;
        }

        static int GetFractions(DateTime dt) {
            return (int)(dt.Ticks - new DateTime(dt.Year, dt.Month, dt.Day, dt.Hour, dt.Minute, dt.Second).Ticks);
        }

        static int GetFractions(DateTimeOffset dt) {
            return (int)(dt.Ticks - new DateTime(dt.Year, dt.Month, dt.Day, dt.Hour, dt.Minute, dt.Second).Ticks);
        }

        /*
        const long SqlDateTicks2Ticks = (long)10000 * 1000 * 60 * 60 * 24;
        const long SqlBaseDate = 693595;

        public static void DateTime2SqlDateTime(DateTime datetime, out int dateticks, out uint timeticks) {
            dateticks = (int)(datetime.Ticks / SqlDateTicks2Ticks) - 693595;
            double time = (double)(datetime.Ticks % SqlDateTicks2Ticks);
            time = time / 10000; // adjust to ms
            time = time * 0.3 + .5;  // adjust to sqlticks (and round correctly)
            timeticks = (uint)time;
        }
        public static void DateTime2SqlSmallDateTime(DateTime datetime, out short dateticks, out ushort timeticks) {
            dateticks = (short)((int)(datetime.Ticks / SqlDateTicks2Ticks) - 693595);
            int time = (int)(datetime.Ticks % SqlDateTicks2Ticks);
            timeticks = (ushort)(time / (10000 * 1000 * 60)); // adjust to min
        }
        public static long DateTime2XsdTime(DateTime datetime) {
            // adjust to ms
            return (datetime.TimeOfDay.Ticks / 10000) * 4 + 0; 
        }
        public static long DateTime2XsdDateTime(DateTime datetime) {
            long t = datetime.TimeOfDay.Ticks / 10000;
            t += (datetime.Day-1) * (long)1000*60*60*24;
            t += (datetime.Month-1) * (long)1000*60*60*24*31;
            int year = datetime.Year;
            if (year < -9999 || year > 9999)
                throw new XmlException(Res.SqlTypes_ArithOverflow, (string)null);
            t += (datetime.Year+9999) * (long)1000*60*60*24*31*12;
            return t*4 + 2;
        }
        public static long DateTime2XsdDate(DateTime datetime) {
            // compute local offset
            long tzOffset = -TimeZone.CurrentTimeZone.GetUtcOffset(datetime).Ticks  / TimeSpan.TicksPerMinute;
            tzOffset += 14*60;
            // adjust datetime to UTC
            datetime = TimeZone.CurrentTimeZone.ToUniversalTime(datetime);

            Debug.Assert( tzOffset >= 0 );

            int year = datetime.Year;
            if (year < -9999 || year > 9999)
                throw new XmlException(Res.SqlTypes_ArithOverflow, (string)null);
            long t = (datetime.Day - 1) 
                 + 31*(datetime.Month - 1)
                 + 31*12*((long)(year+9999));
            t *= (29*60); // adjust in timezone
            t += tzOffset;
            return t*4+1;
        }
         * */
    }
}