public static BigDecimal DivideToIntegralValue(BigDecimal dividend, BigDecimal divisor, MathContext mc)
{
int mcPrecision = mc.Precision;
int diffPrecision = dividend.Precision - divisor.Precision;
int lastPow = BigDecimal.TenPow.Length - 1;
long diffScale = (long)dividend.Scale - divisor.Scale;
long newScale = diffScale;
long quotPrecision = diffPrecision - diffScale + 1;
BigInteger quotient;
BigInteger remainder;
// In special cases it call the dual method
if ((mcPrecision == 0) || (dividend.IsZero) || (divisor.IsZero))
{
return(DivideToIntegralValue(dividend, divisor));
}
// Let be: this = [u1,s1] and divisor = [u2,s2]
if (quotPrecision <= 0)
{
quotient = BigInteger.Zero;
}
else if (diffScale == 0)
{
// CASE s1 == s2: to calculate u1 / u2
quotient = dividend.UnscaledValue / divisor.UnscaledValue;
}
else if (diffScale > 0)
{
// CASE s1 >= s2: to calculate u1 / (u2 * 10^(s1-s2)
quotient = dividend.UnscaledValue / (divisor.UnscaledValue * Multiplication.PowerOf10(diffScale));
// To chose 10^newScale to get a quotient with at least 'mc.precision()' digits
newScale = System.Math.Min(diffScale, System.Math.Max(mcPrecision - quotPrecision + 1, 0));
// To calculate: (u1 / (u2 * 10^(s1-s2)) * 10^newScale
quotient = quotient * Multiplication.PowerOf10(newScale);
}
else
{
// CASE s2 > s1:
/* To calculate the minimum power of ten, such that the quotient
* (u1 * 10^exp) / u2 has at least 'mc.precision()' digits. */
long exp = System.Math.Min(-diffScale, System.Math.Max((long)mcPrecision - diffPrecision, 0));
long compRemDiv;
// Let be: (u1 * 10^exp) / u2 = [q,r]
quotient = BigMath.DivideAndRemainder(dividend.UnscaledValue * Multiplication.PowerOf10(exp),
divisor.UnscaledValue, out remainder);
newScale += exp; // To fix the scale
exp = -newScale; // The remaining power of ten
// If after division there is a remainder...
if ((remainder.Sign != 0) && (exp > 0))
{
// Log10(r) + ((s2 - s1) - exp) > mc.precision ?
compRemDiv = (new BigDecimal(remainder)).Precision
+ exp - divisor.Precision;
if (compRemDiv == 0)
{
// To calculate: (r * 10^exp2) / u2
remainder = (remainder * Multiplication.PowerOf10(exp)) / divisor.UnscaledValue;
compRemDiv = System.Math.Abs(remainder.Sign);
}
if (compRemDiv > 0)
{
// The quotient won't fit in 'mc.precision()' digits
// math.06=Division impossible
throw new ArithmeticException(Messages.math06); //$NON-NLS-1$
}
}
}
// Fast return if the quotient is zero
if (quotient.Sign == 0)
{
return(BigDecimal.GetZeroScaledBy(diffScale));
}
BigInteger strippedBI = quotient;
BigDecimal integralValue = new BigDecimal(quotient);
long resultPrecision = integralValue.Precision;
int i = 1;
// To strip trailing zeros until the specified precision is reached
while (!BigInteger.TestBit(strippedBI, 0))
{
quotient = BigMath.DivideAndRemainder(strippedBI, BigDecimal.TenPow[i], out remainder);
if ((remainder.Sign == 0) &&
((resultPrecision - i >= mcPrecision) ||
(newScale - i >= diffScale)))
{
resultPrecision -= i;
newScale -= i;
if (i < lastPow)
{
i++;
}
strippedBI = quotient;
}
else
{
if (i == 1)
{
break;
}
i = 1;
}
}
// To check if the result fit in 'mc.precision()' digits
if (resultPrecision > mcPrecision)
{
// math.06=Division impossible
throw new ArithmeticException(Messages.math06); //$NON-NLS-1$
}
integralValue.Scale = BigDecimal.ToIntScale(newScale);
integralValue.SetUnscaledValue(strippedBI);
return(integralValue);
}
public static bool TryParse(char[] inData, int offset, int len, IFormatProvider provider, out BigDecimal value,
out Exception exception)
{
if (inData == null || inData.Length == 0)
{
exception = new FormatException("Cannot parse an empty string.");
value = null;
return(false);
}
var numberformatInfo = provider.GetFormat(typeof(NumberFormatInfo)) as NumberFormatInfo;
if (numberformatInfo == null)
{
numberformatInfo = NumberFormatInfo.CurrentInfo;
}
var decSep = numberformatInfo.NumberDecimalSeparator;
if (decSep.Length > 1)
{
exception = new NotSupportedException("More than one decimal separator not yet supported");
value = null;
return(false);
}
var cDecSep = decSep[0];
int begin = offset; // first index to be copied
int last = offset + (len - 1); // last index to be copied
if ((last >= inData.Length) || (offset < 0) || (len <= 0) || (last < 0))
{
exception = new FormatException();
value = null;
return(false);
}
var v = new BigDecimal();
try {
var unscaledBuffer = new StringBuilder(len);
int bufLength = 0;
// To skip a possible '+' symbol
if ((offset <= last) && (inData[offset] == '+'))
{
offset++;
begin++;
}
int counter = 0;
bool wasNonZero = false;
// Accumulating all digits until a possible decimal point
for (;
(offset <= last) &&
(inData[offset] != cDecSep) &&
(inData[offset] != 'e') &&
(inData[offset] != 'E');
offset++)
{
if (!wasNonZero)
{
if (inData[offset] == '0')
{
counter++;
}
else
{
wasNonZero = true;
}
}
}
unscaledBuffer.Append(inData, begin, offset - begin);
bufLength += offset - begin;
// A decimal point was found
if ((offset <= last) && (inData[offset] == cDecSep))
{
offset++;
// Accumulating all digits until a possible exponent
begin = offset;
for (;
(offset <= last) &&
(inData[offset] != 'e') &&
(inData[offset] != 'E');
offset++)
{
if (!wasNonZero)
{
if (inData[offset] == '0')
{
counter++;
}
else
{
wasNonZero = true;
}
}
}
v.Scale = offset - begin;
bufLength += v.Scale;
unscaledBuffer.Append(inData, begin, v.Scale);
}
else
{
v.Scale = 0;
}
// An exponent was found
if ((offset <= last) && ((inData[offset] == 'e') || (inData[offset] == 'E')))
{
offset++;
// Checking for a possible sign of scale
begin = offset;
if ((offset <= last) && (inData[offset] == '+'))
{
offset++;
if ((offset <= last) && (inData[offset] != '-'))
{
begin++;
}
}
// Accumulating all remaining digits
string scaleString = new String(inData, begin, last + 1 - begin); // buffer for scale
// Checking if the scale is defined
long newScale = (long)v.Scale - Int32.Parse(scaleString, provider); // the new scale
v.Scale = (int)newScale;
if (newScale != v.Scale)
{
// math.02=Scale out of range.
throw new FormatException(Messages.math02); //$NON-NLS-1$
}
}
// Parsing the unscaled value
if (bufLength < 19)
{
long smallValue;
if (!Int64.TryParse(unscaledBuffer.ToString(), NumberStyles.Integer, provider, out smallValue))
{
value = null;
exception = new FormatException();
return(false);
}
v.SmallValue = smallValue;
v.BitLength = BigDecimal.CalcBitLength(v.SmallValue);
}
else
{
v.SetUnscaledValue(BigInteger.Parse(unscaledBuffer.ToString()));
}
v.Precision = unscaledBuffer.Length - counter;
if (unscaledBuffer[0] == '-')
{
v.Precision--;
}
value = v;
exception = null;
return(true);
} catch (Exception ex) {
exception = ex;
value = null;
return(false);
}
}
