/// <summary>
/// Adapted from https://github.com/google/brotli/blob/master/c/enc/compress_fragment.c (BrotliCompressFragmentFastImpl, two occurrences).
/// </summary>
public int UpdateAndGetCandidate(int ip, int baseIp)
{
ulong inputBytes = HasherCommon.Load64LE(input, ip - 3);
uint prevHash = HashBytesAtOffset(inputBytes, 0, shift);
uint curHash = HashBytesAtOffset(inputBytes, 3, shift);
table[prevHash] = ip - baseIp - 3;
prevHash = HashBytesAtOffset(inputBytes, 1, shift);
table[prevHash] = ip - baseIp - 2;
prevHash = HashBytesAtOffset(inputBytes, 2, shift);
table[prevHash] = ip - baseIp - 1;
int candidate = baseIp + table[curHash];
table[curHash] = ip - baseIp;
return(candidate);
}
/// <summary>
/// Adapted from https://github.com/google/brotli/blob/master/c/enc/compress_fragment.c (Hash).
/// </summary>
private static uint Hash(byte[] bytes, int index, int shift)
{
ulong h = unchecked ((HasherCommon.Load64LE(bytes, index) << 24) * HashMul32);
return((uint)(h >> shift));
}