public override long NextInt64(long minValue, long maxValue)
{
ulong exclusiveRange = (ulong)(maxValue - minValue);
if (exclusiveRange <= int.MaxValue)
{
return(Next((int)exclusiveRange) + minValue);
}
if (exclusiveRange > 1)
{
// Narrow down to the smallest range [0, 2^bits] that contains maxValue.
// Then repeatedly generate a value in that outer range until we get one within the inner range.
int bits = BitOperations.Log2Ceiling(exclusiveRange);
while (true)
{
ulong result = NextUInt64() >> (sizeof(ulong) * 8 - bits);
if (result < exclusiveRange)
{
return((long)result + minValue);
}
}
}
Debug.Assert(minValue == maxValue || minValue + 1 == maxValue);
return(minValue);
}
public override long NextInt64(long maxValue)
{
if (maxValue <= int.MaxValue)
{
return(Next((int)maxValue));
}
if (maxValue > 1)
{
// Narrow down to the smallest range [0, 2^bits] that contains maxValue.
// Then repeatedly generate a value in that outer range until we get one within the inner range.
int bits = BitOperations.Log2Ceiling((ulong)maxValue);
while (true)
{
ulong result = NextUInt64() >> (sizeof(ulong) * 8 - bits);
if (result < (ulong)maxValue)
{
return((long)result);
}
}
}
Debug.Assert(maxValue == 0 || maxValue == 1);
return(0);
}
