public DirectBuffer this[int index]
{
[MethodImpl(MethodImplOptions.AggressiveInlining)]
get
{
if ((uint)index >= BufferCount)
{
BuffersThrowHelper.ThrowIndexOutOfRange();
}
// ReSharper disable once ImpureMethodCallOnReadonlyValueField
return(DirectBuffer.Slice(index * BufferSize, BufferSize));
}
}
public static int IndexToOffset(int index, int head, int len)
{
if (AdditionalCorrectnessChecks.Enabled && (head < 0 || len < 0))
{
BuffersThrowHelper.ThrowIndexOutOfRange();
}
// return (head + index) % len;
// len is not guaranteed to be power of 2, cannot use bit mask
// but we could avoid branch: we do not need modulo
// instead we only need to subtract len if we wrap over it
var offset = head + index;
var isWrapped = (len - (offset + 1)) >> 31; // 0 or -1
var result = offset + isWrapped * len;
if (AdditionalCorrectnessChecks.Enabled)
{
ThrowHelper.Assert(result >= 0);
ThrowHelper.Assert(result < len);
}
return(result);
}
