public static uint Hash(uint adler, ReadOnlySpan <byte> buff)
{
uint len = (uint)buff.Length;
if (len == 0)
{
return(1);
}
if (len == 1)
{
uint sum2 = adler >> 16 & 0xffff;
adler &= 0xffff;
adler += buff[0];
if (adler >= BASE)
{
adler -= BASE;
}
sum2 += adler;
if (sum2 >= BASE)
{
sum2 -= BASE;
}
return(adler | (sum2 << 16));
}
if (len < 16)
{
uint sum2 = adler >> 16 & 0xffff;
adler &= 0xffff;
for (int i = 0; i < len; i++)
{
adler += buff[i];
sum2 += adler;
}
if (adler >= BASE)
{
adler -= BASE;
}
sum2 %= BASE;
return(adler | (sum2 << 16));
}
#if NETCOREAPP3_1 || NET5_0
if (Avx2.IsSupported)
{
return(Adler32.HashAvx2(adler, buff));
}
if (Ssse3.IsSupported)
{
return(Adler32.HashSsse3(adler, buff));
}
#endif
unsafe
{
fixed(byte *bufPtr = buff)
{
uint sum2 = adler >> 16 & 0xffff;
adler &= 0xffff;
int dof = 0;
while (len >= NMAX)
{
len -= NMAX;
uint n = NMAX / 16;
do
{
Do(ref adler, ref sum2, buff, dof, 16);
dof += 16;
} while (--n > 0);
adler %= BASE;
sum2 %= BASE;
}
if (len > 0)
{
while (len >= 16)
{
len -= 16;
Do(ref adler, ref sum2, buff, dof, 16);
dof += 16;
}
while (len-- > 0)
{
adler += bufPtr[dof++];
sum2 += adler;
}
adler %= BASE;
sum2 %= BASE;
}
return(adler | (sum2 << 16));
}
}
}
public static long UpdateAdler32(uint partial, ReadOnlyMemory <byte> buffer)
{
return(Adler32.Hash(partial, buffer.Span));
}
public static uint ComputeGoogleAdler32(ReadOnlyMemory <byte> buffer)
{
return(Adler32.Hash(0, buffer.Span));
}
public static uint ComputeXdelta3Adler32(ReadOnlyMemory <byte> buffer)
{
return(Adler32.Hash(1, buffer.Span));
}
