internal static BigInteger FindPowerOfTenFromBig(BigInteger bigintExponent)
{
int sign=bigintExponent.Sign;
if(sign<0)return BigInteger.Zero;
if (sign == 0) return BigInteger.One;
if (bigintExponent.CompareTo(BigInt36) <= 0) {
return FindPowerOfTen((int)bigintExponent);
}
FastInteger intcurexp = FastInteger.FromBig(bigintExponent);
BigInteger mantissa = BigInteger.One;
BigInteger bigpow = BigInteger.Zero;
while (intcurexp.Sign > 0) {
if (intcurexp.CompareToInt(18) <= 0) {
bigpow = FindPowerOfTen(intcurexp.AsInt32());
mantissa *= (BigInteger)bigpow;
break;
} else if (intcurexp.CompareToInt(9999999) <= 0) {
int val = intcurexp.AsInt32();
bigpow = FindPowerOfFive(val);
bigpow <<= val;
mantissa *= (BigInteger)bigpow;
break;
} else {
if (bigpow.IsZero) {
bigpow = FindPowerOfFive(9999999);
bigpow <<= 9999999;
}
mantissa *= bigpow;
intcurexp.AddInt(-9999999);
}
}
return mantissa;
}
/// <summary> </summary>
/// <param name='exponentMin'>A BigInteger object.</param>
/// <param name='exponentMax'>A BigInteger object.</param>
/// <returns>A PrecisionContext object.</returns>
public PrecisionContext WithExponentRange(BigInteger exponentMin, BigInteger exponentMax) {
if((exponentMin)==null)throw new ArgumentNullException("exponentMin");
if(exponentMin.CompareTo(exponentMax)>0)
throw new ArgumentException("exponentMin greater than exponentMax");
PrecisionContext pc = this.Copy();
pc.hasExponentRange=true;
pc.exponentMin=exponentMin;
pc.exponentMax=exponentMax;
return pc;
}
private static decimal BigIntegerToDecimal(BigInteger bi)
{
if(bi.Sign<0){
if(bi.CompareTo(DecimalMinValue)<0)
throw new OverflowException();
bi=-bi;
return EncodeDecimal(bi,0,true);
}
if(bi.CompareTo(DecimalMaxValue)>0)
throw new OverflowException();
return EncodeDecimal(bi,0,false);
}
/// <summary> </summary>
/// <param name='exponent'>A BigInteger object.</param>
/// <returns>A Boolean object.</returns>
public bool ExponentWithinRange(BigInteger exponent){
if((exponent)==null)throw new ArgumentNullException("exponent");
if(!this.HasExponentRange)
return true;
if(bigintPrecision.IsZero){
// Only check EMax, since with an unlimited
// precision, any exponent less than EMin will exceed EMin if
// the mantissa is the right size
return exponent.CompareTo(this.EMax)<=0;
} else {
BigInteger bigint=exponent;
bigint+=(BigInteger)bigintPrecision;
bigint-=BigInteger.One;
if(bigint.CompareTo(this.EMin)<0)
return false;
if(exponent.CompareTo(this.EMax)>0)
return false;
return true;
}
}
