| public static __hash__ ( BigInteger self ) : int | ||
| self | BigInteger | |
| return | int | |
public static int __hash__(double d)
{
// Python allows equality between floats, ints, and big ints.
if ((d % 1) == 0)
{
// This double represents an integer, so it must hash like an integer.
if (Int32.MinValue <= d && d <= Int32.MaxValue)
{
return(((int)d).GetHashCode());
}
// Big integer
BigInteger b = (BigInteger)d;
return(BigIntegerOps.__hash__(b));
}
// Special values
if (double.IsInfinity(d))
{
return(d > 0 ? 314159 : -271828);
}
else if (double.IsNaN(d))
{
return(0);
}
return(d.GetHashCode());
}
public static int __hash__(double d)
{
// Special values
if (double.IsPositiveInfinity(d))
{
return(314159);
}
if (double.IsNegativeInfinity(d))
{
return(-314159);
}
if (double.IsNaN(d))
{
return(0);
}
if (d == 0)
{
return(0);
}
// it's an integer!
if (d == Math.Truncate(d))
{
// Use this constant since long.MaxValue doesn't cast precisely to a double
const double maxValue = (ulong)long.MaxValue + 1;
if (long.MinValue <= d && d < maxValue)
{
return(Int64Ops.__hash__((long)d));
}
return(BigIntegerOps.__hash__((BigInteger)d));
}
DecomposeDouble(d, out int sign, out int exponent, out long mantissa);
// make sure the mantissa is not even
while ((mantissa & 1) == 0)
{
mantissa >>= 1;
exponent++;
}
Debug.Assert(exponent <= 0);
var exp = exponent % 31;
var invmod = exp == 0 ? 1 : (1 << (31 + exp));
return(unchecked ((int)(sign * (((mantissa % int.MaxValue) * invmod) % int.MaxValue))));
void DecomposeDouble(in double x, out int Sign, out int Exponent, out long Mantissa)
{
Debug.Assert(x != 0 && !double.IsInfinity(x) && !double.IsNaN(x));
var RawBits = (ulong)BitConverter.DoubleToInt64Bits(x);
var RawSign = (int)(RawBits >> 63);
var RawExponent = (int)(RawBits >> 52) & 0x7FF;
var RawMantissa = (long)(RawBits & 0x000FFFFFFFFFFFFF);
var IsDenormal = RawExponent == 0 && RawMantissa != 0;
// assumes not infinity, not zero and not NaN
Sign = 1 - RawSign * 2;
Mantissa = IsDenormal ? RawMantissa : RawMantissa | 0x0010000000000000;
Exponent = IsDenormal ? -1074 : RawExponent - 1075;
}
}
