C# SqlDecimal.AssertValid方法代码示例

 // Truncate - Truncate the numeric to a specific digit
 /// <devdoc>
 ///    <para>[To be supplied.]</para>
 /// </devdoc>
 public static SqlDecimal Truncate(SqlDecimal n, int position)
 {
     n.AssertValid();
     return Round(n, position, true);
 }

        // Power - Compute the power of a numeric
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        public static SqlDecimal Power(SqlDecimal n, double exp)
        {
            n.AssertValid();

            if (n.IsNull)
                return SqlDecimal.Null;

            byte prec = n.Precision;
            int scale = n.Scale;
            double dBaseNum = n.ToDouble();

            n = new SqlDecimal(Math.Pow(dBaseNum, exp));
            n.AdjustScale(scale - (int)n.Scale, true);

            n.m_bPrec = MaxPrecision;

            return n;
        }

        private static SqlDecimal Round(SqlDecimal n, int lPosition, bool fTruncate)
        {
            if (n.IsNull)
                return SqlDecimal.Null;

            if (lPosition >= 0)
            {
                //If round to the right of decimal number
                lPosition = Math.Min(s_NUMERIC_MAX_PRECISION, lPosition);
                if (lPosition >= n.m_bScale)
                    return n;   //No need to round
            }
            else
            {
                //If round to the left of the decimal point
                lPosition = Math.Max(-s_NUMERIC_MAX_PRECISION, lPosition);

                //Return +0.00 if truncation of integer part
                if (lPosition < n.m_bScale - n.m_bPrec)
                {
                    n.SetToZero();
                    return n;
                }
            }

            uint ulRem = 0;                                         // Remainder: the highest significant digit to be truncated
            int lAdjust = Math.Abs(lPosition - (int)n.m_bScale);    // Precision adjustment
            uint ulLastDivBase = 1;                                 //

            //Compute the integral part of the numeric
            while (lAdjust > 0)
            {
                if (lAdjust >= 9)
                {
                    ulRem = n.DivByULong(s_rgulShiftBase[8]);
                    ulLastDivBase = s_rgulShiftBase[8];
                    lAdjust -= 9;
                }
                else
                {
                    ulRem = n.DivByULong(s_rgulShiftBase[lAdjust - 1]);
                    ulLastDivBase = s_rgulShiftBase[lAdjust - 1];
                    lAdjust = 0;
                }
            }

            // The rounding only depends on the first digit after the rounding position
            if (ulLastDivBase > 1)
            {
                ulRem /= (ulLastDivBase / 10);
            }

            //If result is zero, return
            if (n.FZero() && (fTruncate || ulRem < 5))
            {
                n.SetPositive();
                n.AssertValid();
                return n;
            }

            // Adjust by adding 1 if remainder is larger than 5
            if (ulRem >= 5 && !fTruncate)
                n.AddULong(1);

            // Convert back to original scale
            lAdjust = Math.Abs(lPosition - n.m_bScale);

            while (lAdjust-- > 0)
            {
                n.MultByULong(s_ulBase10);
            }

            n.AssertValid();
            return n;
        }

        // Floor - next largest integer smaller or equal to the numeric
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        public static SqlDecimal Floor(SqlDecimal n)
        {
            n.AssertValid();

            if (n.IsNull)
                return SqlDecimal.Null;

            if (n.m_bScale == 0)
                return n;

            bool fFraction;    //Fractional flag

            n.MakeInteger(out fFraction);

            //When the numeric has fraction and is negative, subtract 1 by calling AddULong(1)
            //Otherwise return the integral part.
            if (fFraction && !n.IsPositive)
            {
                n.AddULong(1);
            }

            if (n.FZero())//if result is zero, sign should be positive
                n.SetPositive();
            n.AssertValid();
            return n;
        }

        // Sign -   1 if positive, -1 if negative
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        public static SqlInt32 Sign(SqlDecimal n)
        {
            n.AssertValid();

            if (n.IsNull)
                return SqlInt32.Null;

            if (n == new SqlDecimal(0))
                return SqlInt32.Zero;
            else
                return n.IsNull ? SqlInt32.Null :
                    (n.IsPositive ? new SqlInt32(1) : new SqlInt32(-1));
        }

        //    CmpCompareNm()
        //
        //    Compare the value of two numerics
        //
        //    Complexity: O(pn) p: precision  n: length
        //
        //  Parameters:
        //        this    - IN Operand1
        //        snumOp    - IN operand2
        //
        //    Returns:
        //        EComparison.LT    - this < snumOp
        //        EComparison.EQ        - this = snumOp
        //        EComparison.GT    - this > snumOp
        //
        private EComparison CompareNm
        (
        SqlDecimal snumOp
        )
        {
            AssertValid();
            snumOp.AssertValid();

            //Signs of the two numeric operands
            int Sign1;
            int Sign2;

            int iFinalResult;   //Final result of comparison: positive = greater
                                //than, 0 = equal, negative = less than

            //Initialize the sign values to be 1(positive) or -1(negative)
            Sign1 = IsPositive ? 1 : -1;
            Sign2 = snumOp.IsPositive ? 1 : -1;

            if (Sign1 != Sign2) //If different sign, the positive one is greater
                return Sign1 == 1 ? EComparison.GT : EComparison.LT;

            else
            { //same sign, have to compare absolute values
                //Temporary memory to hold the operand since it is const
                //but its scale may get adjusted during comparison
                int ScaleDiff;
                SqlDecimal snumArg1 = this;
                SqlDecimal snumArg2 = snumOp;

                //First make the two operands the same scale if necessary
                ScaleDiff = ((int)m_bScale) - ((int)snumOp.m_bScale);

                if (ScaleDiff < 0)
                {
                    //If increasing the scale of operand1 caused an overflow,
                    //then its absolute value is greater than that of operand2.
                    try
                    {
                        snumArg1.AdjustScale(-ScaleDiff, true);
                    }
                    catch (OverflowException)
                    {
                        return (Sign1 > 0) ? EComparison.GT : EComparison.LT;
                    }
                }
                else if (ScaleDiff > 0)
                {
                    //If increasing the scale of operand2 caused an overflow, then
                    //operand1's absolute value is less than that of operand2.
                    try
                    {
                        snumArg2.AdjustScale(ScaleDiff, true);
                    }
                    catch (OverflowException)
                    {
                        return (Sign1 > 0) ? EComparison.LT : EComparison.GT;
                    }
                }

                //Compare the absolute value of the two numerics
                //Note: We are sure that scale of arguments is the same,
                //      so LAbsCmp() will not modify its argument.
                int lResult = snumArg1.LAbsCmp(snumArg2);
                if (0 == lResult)
                    return EComparison.EQ;

                //if both positive, result same as result from LAbsCmp;
                //if both negative, result reverse of result from LAbsCmp
                iFinalResult = Sign1 * lResult;

                if (iFinalResult < 0)
                    return EComparison.LT;
                else
                    return EComparison.GT;
            }
        }

        // Builtin functions

        // Abs - absolute value
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        public static SqlDecimal Abs(SqlDecimal n)
        {
            n.AssertValid();

            if (n.IsNull)
                return SqlDecimal.Null;

            n.SetPositive();
            n.AssertValid();
            return n;
        }

        // Convert to a specific precision and scale
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        public static SqlDecimal ConvertToPrecScale(SqlDecimal n, int precision, int scale)
        {
            CheckValidPrecScale(precision, scale);
            n.AssertValid();

            if (n.IsNull)
                return SqlDecimal.Null;

            SqlDecimal ret = n;

            int lPrecAdjust = precision - (int)ret.m_bPrec;//Adjustment to precision
            int lScaleAdjust = scale - (int)ret.m_bScale;//Adjustment to scale

            //Adjust scale
            ret.AdjustScale(lScaleAdjust, true);

            // devnote: is that still true?
            //Shouldn't truncate the integer digits; BActualPrec() is an expensive
            //function call, so test the data length first to eliminate majority
            //of cases

            //The number of bytes storage required by the new precision
            byte cbWithNewPrec = CLenFromPrec((byte)precision);

            if (cbWithNewPrec < ret.m_bLen)
            {
                //if current actual length greater than length corresponding to bNewPrec
                //there must be truncating
                throw new SqlTruncateException();
            }
            else if (cbWithNewPrec == ret.m_bLen)
            {
                //if the two lengths equal, need to check the actual precision
                if (precision < ret.CalculatePrecision())
                    throw new SqlTruncateException();
            }

            //Adjust precision
            ret.m_bPrec = (byte)precision;

            ret.AssertValid();

            return ret;
        }

        //-----------------------------------------------------------
        //DivNm():
        //  Divide numeric by numeric.
        //    The Quotient will be returned in *this
        //
        //Result scale & precision:
        //    NOTE: same as in Hydra but different from SQL Server Manual,
        //            where scale = max(s1+p2-s2+1,x_cNumeDivScaleMin)):
        //        scale = max(s1 + p2 + 1, x_cNumeDivScaleMin);
        //        precision = max(s1 + p2 + 1, x_cNumeDivScaleMin) + p1 + p2 + 1;
        //
        //Overflow Rules:
        //        If scale is greater than NUMERIC_MAX_PRECISION it is set to
        //    NUMERIC_MAX_PRECISION.  If precision is greater than NUMERIC_MAX_PRECISION
        //    it's set to NUMERIC_MAX_PRECISION, then scale is reduced to keep the
        //    integer part untruncated but keeping a minimum value of x_cNumeDivScaleMin.
        //    For example, if using the above formula, the resulting precision is 46 and
        //    scale is 10, the precision will be reduced to 38, to keep the integral part
        //    untruncated the scale needs be reduced to 2, but since x_cNumeDivScaleMin
        //    is set to 6 currently, resulting scale will be 6.
        //        OverflowException is thrown only if the actual precision is greater than
        //    NUMERIC_MAX_PRECISION or actual length is greater than x_cbNumeBuf
        //
        //Algorithm
        //  Call general purpose arbitrary precision division routine with scale = 0.
        //    Scale,prec adjusted later.
        //
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        public static SqlDecimal operator /(SqlDecimal x, SqlDecimal y)
        {
            if (x.IsNull || y.IsNull)
                return Null;

            x.AssertValid();
            y.AssertValid();

            // Variables for figuring prec,scale
            int bScaleD;            // Input Scale of dividend (output scale of remainder)
            int bPrecD;             // Input Prec of dividend (output prec of remainder)
            int ResScale;           // Final scale we will force quotient to
            int ResPrec;            // Final precision we will force quotient to
            int ResInteger;         // # of digits in integer part of result (prec-scale)
            int MinScale;           // Temp to help compute ResScale
            int lScaleAdjust;       // How much result scale will be adjusted
            bool fResSignPos;       // sign of result

            // Steps:
            //    1) Figure result prec,scale; adjust scale of dividend
            //    2) Compute result remainder/quotient in 0 scale numbers
            //    3) Set result prec,scale and adjust as necessary

            // 0) Check for Div by 0
            if (y.FZero())
                throw new DivideByZeroException(SQLResource.DivideByZeroMessage);

            // 1) Figure out result prec,scale,sign..
            fResSignPos = (x.IsPositive == y.IsPositive);//sign of result

            //scale = max(s1 + p2 + 1, x_cNumeDivScaleMin);
            //precision = max(s1 + p2 + 1, x_cNumeDivScaleMin) + p1 + p2 + 1;
            //For backward compatibility, use exactly the same scheme as in Hydra
            bScaleD = x.m_bScale;
            bPrecD = x.m_bPrec;
            ResScale = Math.Max(x.m_bScale + y.m_bPrec + 1, s_cNumeDivScaleMin);
            ResInteger = x.m_bPrec - x.m_bScale + y.m_bScale;
            MinScale = Math.Min(ResScale, s_cNumeDivScaleMin);

            ResInteger = Math.Min(ResInteger, s_NUMERIC_MAX_PRECISION);
            ResPrec = ResInteger + ResScale;

            if (ResPrec > s_NUMERIC_MAX_PRECISION)
                ResPrec = s_NUMERIC_MAX_PRECISION;

            // If overflow, reduce the scale to avoid truncation of data
            ResScale = Math.Min((ResPrec - ResInteger), ResScale);
            ResScale = Math.Max(ResScale, MinScale);

            //Adjust the scale of the dividend
            lScaleAdjust = ResScale - (int)x.m_bScale + (int)y.m_bScale;
            x.AdjustScale(lScaleAdjust, true);

            // Step2: Actual Computation

            uint[] rgulData1 = new uint[4] { x.m_data1, x.m_data2, x.m_data3, x.m_data4 };
            uint[] rgulData2 = new uint[4] { y.m_data1, y.m_data2, y.m_data3, y.m_data4 };

            // Buffers for arbitrary precision divide
            uint[] rgulR = new uint[s_cNumeMax + 1];
            uint[] rgulQ = new uint[s_cNumeMax];
            // # of ULONGs in result
            int culQ, culR;

            // Divide mantissas. V is not zero - already checked.
            // Cannot overflow, as Q <= U, R <= V. (and both are positive)
            MpDiv(rgulData1, x.m_bLen, rgulData2, y.m_bLen, rgulQ, out culQ, rgulR, out culR);

            // Construct the result from Q
            ZeroToMaxLen(rgulQ, culQ);
//.........这里部分代码省略.........

        //    MultNm()
        //
        //    Multiply two numerics.
        //
        //  Parameters:
        //        x    - IN Multiplier
        //        y    - IN Multiplicand
        //
        //    Result scale and precision(same as in SQL Server Manual and Hydra):
        //        scale = s1 + s2
        //        precision = s1 + s2 + (p1 - s1) + (p2 - s2) + 1
        //
        //    Overflow Rules:
        //        If scale is greater than NUMERIC_MAX_PRECISION it is set to
        //    NUMERIC_MAX_PRECISION.  If precision is greater than NUMERIC_MAX_PRECISION
        //    it is set to NUMERIC_MAX_PRECISION, then scale is reduced to keep the
        //    integer part untruncated but keeping a minimum value of x_cNumeDivScaleMin.
        //    For example, if using the above formula, the resulting precision is 46 and
        //    scale is 10, the precision will be reduced to 38. To keep the integral part
        //    untruncated the scale needs be reduced to 2, but since x_cNumeDivScaleMin
        //    is set to 6 currently, resulting scale will be 6.
        //        O_OVERFLOW is returned only if the actual precision is greater than
        //     NUMERIC_MAX_PRECISION or the actual length is greater than x_cbNumeBuf.
        //
        //    Algorithm:
        //        Starting from the lowest significant UI4, for each UI4 of the multiplier
        //    iterate through the UI4s of the multiplicand starting from
        //    the least significant UI4s, multiply the multiplier UI4 with
        //    multiplicand UI4, update the result buffer with the product modulo
        //    x_dwlBaseUI4 at the same index as the multiplicand, and carry the quotient to
        //    add to the next multiplicand UI4.  Until the end of the multiplier data
        //    array is reached.
        //
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        public static SqlDecimal operator *(SqlDecimal x, SqlDecimal y)
        {
            x.AssertValid();
            y.AssertValid();

            if (x.IsNull || y.IsNull)
                return Null;

            //Implementation:
            //        I) Figure result scale,prec
            //        II) Perform mult.
            //        III) Adjust product to result scale,prec

            // Local variables for actual multiplication
            int iulPlier;           //index of UI4 in the Multiplier
            uint ulPlier;            //current multiplier UI4
            ulong dwlAccum;           //accumulated sum
            ulong dwlNextAccum;       //overflow of accumulated sum
            int culCand = y.m_bLen; //length of multiplicand in UI4s

            //Local variables to track scale,precision
            int ActualScale;                    // Scale after mult done
            int ResScale;                       // Final scale we will force result to
            int ResPrec;                        // Final precision we will force result to
            int ResInteger;                     // # of digits in integer part of result (prec-scale)
            int lScaleAdjust;   //How much result scale will be adjusted
            bool fResPositive;  // Result sign

            SqlDecimal ret;


            //I) Figure result prec,scale
            ActualScale = x.m_bScale + y.m_bScale;
            ResScale = ActualScale;
            ResInteger = (x.m_bPrec - x.m_bScale) + (y.m_bPrec - y.m_bScale) + 1;

            //result precision = s1 + s2 + (p1 - s1) + (p2 - s2) + 1
            ResPrec = ResScale + ResInteger;

            // Downward adjust res prec,scale if either larger than NUMERIC_MAX_PRECISION
            if (ResPrec > s_NUMERIC_MAX_PRECISION)
                ResPrec = s_NUMERIC_MAX_PRECISION;
            if (ResScale > s_NUMERIC_MAX_PRECISION)
                ResScale = s_NUMERIC_MAX_PRECISION;

            //
            // It is possible when two large numbers are being multiplied the scale
            // can be reduced to 0 to keep data untruncated; the fix here is to
            // preserve a minimum scale of 6.
            //
            // If overflow, reduce the scale to avoid truncation of data
            ResScale = Math.Min((ResPrec - ResInteger), ResScale);
            // But keep a minimum scale of NUMERIC_MIN_DVSCALE
            ResScale = Math.Max(ResScale, Math.Min(ActualScale, s_cNumeDivScaleMin));

            lScaleAdjust = ResScale - ActualScale;

            fResPositive = (x.IsPositive == y.IsPositive);//positive if both signs same.

            // II) Perform multiplication

            uint[] rglData1 = new uint[4] { x.m_data1, x.m_data2, x.m_data3, x.m_data4 };
            uint[] rglData2 = new uint[4] { y.m_data1, y.m_data2, y.m_data3, y.m_data4 };

//.........这里部分代码省略.........

        // Binary operators

        // Arithmetic operators
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        public static SqlDecimal operator +(SqlDecimal x, SqlDecimal y)
        {
            if (x.IsNull || y.IsNull)
                return Null;

            ulong dwlAccum;           //accumulated sum
            bool fMySignPos;         //sign of x was positive at start
            bool fOpSignPos;         // sign of y positive at start
            bool fResSignPos = true; //sign of result should be positive
            int MyScale;    //scale of x
            int OpScale;    //scale of y
            int ResScale;   //scale of result
            int ResPrec;    //precision of result
            int ResInteger; //number of digits for the integer part of result
            int culOp1;     //# of UI4s in x
            int culOp2;     //# of UI4s in y
            int iulData;    //which UI4 we are operating on in x, y
            byte bLen;       // length for the result


            x.AssertValid();
            y.AssertValid();

            fMySignPos = x.IsPositive;
            fOpSignPos = y.IsPositive;

            //result scale = max(s1,s2)
            //result precision = max(s1,s2) + max(p1-s1,p2-s2)
            MyScale = x.m_bScale;
            OpScale = y.m_bScale;

            // Calculate the integer part of the result.
            ResInteger = Math.Max((int)x.m_bPrec - MyScale, (int)y.m_bPrec - OpScale);
            Debug.Assert(ResInteger <= MaxPrecision);

            // Calculate the scale of the result.
            ResScale = Math.Max(MyScale, OpScale);
            Debug.Assert(ResScale <= MaxScale);

            // Calculate the precision of the result.
            // Add 1 for final carry.
            ResPrec = ResInteger + ResScale + 1;
            ResPrec = Math.Min(MaxPrecision, ResPrec);

            // If precision adjusted, scale is reduced to keep the integer part untruncated.
            // But discard the extra carry, only keep the integer part as ResInteger, not ResInteger + 1.
            Debug.Assert(ResPrec - ResInteger >= 0);
            if (ResPrec - ResInteger < ResScale)
                ResScale = ResPrec - ResInteger;

            // Adjust both operands to be the same scale as ResScale.
            if (MyScale != ResScale)
                x.AdjustScale(ResScale - MyScale, true);

            if (OpScale != ResScale)
                y.AdjustScale(ResScale - OpScale, true);

            // When sign of first operand is negative
            // negate all operands including result.
            if (!fMySignPos)
            {
                fMySignPos = !fMySignPos;
                fOpSignPos = !fOpSignPos;
                fResSignPos = !fResSignPos;
            }

            // Initialize operand lengths and pointer.
            culOp1 = x.m_bLen;
            culOp2 = y.m_bLen;

            uint[] rglData1 = new uint[4] { x.m_data1, x.m_data2, x.m_data3, x.m_data4 };
            uint[] rglData2 = new uint[4] { y.m_data1, y.m_data2, y.m_data3, y.m_data4 };

            if (fOpSignPos)
            {
                dwlAccum = 0;

                // CONSIDER: Call AddUlong when possible

                // Loop through UI4s adding operands and putting result in *this
                // of the operands and put result in *this
                for (iulData = 0; iulData < culOp1 || iulData < culOp2; iulData++)
                {
                    // None of these DWORDLONG additions can overflow, as dwlAccum comes in < x_lInt32Base
                    if (iulData < culOp1)
                        dwlAccum += rglData1[iulData];
                    if (iulData < culOp2)
                        dwlAccum += rglData2[iulData];

                    rglData1[iulData] = (uint)dwlAccum; // equiv to mod x_lInt32Base
                    dwlAccum >>= 32; // equiv to div x_lInt32Base
                }

                //If carry
//.........这里部分代码省略.........

        // Convert to a specific precision and scale
        public static SqlDecimal ConvertToPrecScale(SqlDecimal n, int precision, int scale)
        {
            CheckValidPrecScale(precision, scale);
            n.AssertValid();

            if (n.IsNull)
                return SqlDecimal.Null;

            SqlDecimal ret = n;

            int lPrecAdjust = precision - ret._bPrec;//Adjustment to precision
            int lScaleAdjust = scale - ret._bScale;//Adjustment to scale

            //Adjust scale
            ret.AdjustScale(lScaleAdjust, true);

            //The number of bytes storage required by the new precision
            byte cbWithNewPrec = CLenFromPrec((byte)precision);

            if (cbWithNewPrec < ret._bLen)
            {
                //if current actual length greater than length corresponding to bNewPrec
                //there must be truncating
                throw new SqlTruncateException();
            }
            else if (cbWithNewPrec == ret._bLen)
            {
                //if the two lengths equal, need to check the actual precision
                if (precision < ret.CalculatePrecision())
                    throw new SqlTruncateException();
            }

            //Adjust precision
            ret._bPrec = (byte)precision;

            ret.AssertValid();

            return ret;
        }