/// <exception cref="System.InvalidOperationException">HashSize set to an invalid value.</exception>
/// <inheritdoc />
protected override byte[] ComputeHashInternal(UnifiedData data)
{
byte[]? hash = null;
switch (HashSize)
{
case 32:
{
var h = (uint)InitVal + _primes32[4];
int dataCount = 0;
byte[]? remainder = null;
var initValues = new[] {
(uint)InitVal + _primes32[0] + _primes32[1],
(uint)InitVal + _primes32[1],
(uint)InitVal,
(uint)InitVal - _primes32[0]
};
data.ForEachGroup(16,
(dataGroup, position, length) => {
for (int x = position; x < position + length; x += 16)
{
for (var y = 0; y < 4; ++y)
{
initValues[y] += BitConverter.ToUInt32(dataGroup, x + y * 4) * _primes32[1];
initValues[y] = initValues[y].RotateLeft(13);
initValues[y] *= _primes32[0];
}
}
dataCount += length;
},
(remainderData, position, length) => {
remainder = new byte[length];
Array.Copy(remainderData, position, remainder, 0, length);
dataCount += length;
});
PostProcess(ref h, initValues, dataCount, remainder);
hash = BitConverter.GetBytes(h);
break;
}
case 64:
{
var h = InitVal + _primes64[4];
int dataCount = 0;
byte[]? remainder = null;
var initValues = new[] {
InitVal + _primes64[0] + _primes64[1],
InitVal + _primes64[1],
InitVal,
InitVal - _primes64[0]
};
data.ForEachGroup(32,
(dataGroup, position, length) => {
for (var x = position; x < position + length; x += 32)
{
for (var y = 0; y < 4; ++y)
{
initValues[y] += BitConverter.ToUInt64(dataGroup, x + y * 8) * _primes64[1];
initValues[y] = initValues[y].RotateLeft(31);
initValues[y] *= _primes64[0];
}
}
dataCount += length;
},
(remainderData, position, length) => {
remainder = new byte[length];
Array.Copy(remainderData, position, remainder, 0, length);
dataCount += length;
});
PostProcess(ref h, initValues, dataCount, remainder);
hash = BitConverter.GetBytes(h);
break;
}
}
return(hash ?? Array.Empty <byte>());
}
/// <summary> /// Computes hash value for given stream. /// </summary> /// <param name="data">Data to hash.</param> /// <returns> /// Hash value of data as byte array. /// </returns> protected abstract byte[] ComputeHashInternal(UnifiedData data);