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);
}
}
