Re: I'm a total push-over..

Hi,

On Sun, 27 Jan 2008, Dmitry Potapov wrote:

#define rot(x,k) (((x)<<(k)) | ((x)>>(32-(k))))

#define mix(a,b,c) \
{ \
	a -= c;  a ^= rot(c, 4);  c += b; \
	b -= a;  b ^= rot(a, 6);  a += c; \
	c -= b;  c ^= rot(b, 8);  b += a; \
	a -= c;  a ^= rot(c,16);  c += b; \
	b -= a;  b ^= rot(a,19);  a += c; \
	c -= b;  c ^= rot(b, 4);  b += a; \
}
#define final(a,b,c) \
{ \
	c ^= b; c -= rot(b,14); \
	a ^= c; a -= rot(c,11); \
	b ^= a; b -= rot(a,25); \
	c ^= b; c -= rot(b,16); \
	a ^= c; a -= rot(c,4);  \
	b ^= a; b -= rot(a,14); \
	c ^= b; c -= rot(b,24); \
}

#define hash_value(x) \
	hs[hp] += (x); \
	if (++hp == 3) { \
		mix (hs[0], hs[1], hs[2]); \
		hp = 0; \
	}
unsigned int name_hash(const char *name, unsigned size)
{
	unsigned hp = 0;
	unsigned hs[3];
	hs[0] = hs[1] = hs[2] = 0xdeadbeef + size;

	do {
		unsigned char c;
		if (size >= sizeof(unsigned)) {
			unsigned val = get_unaligned_uint(name);
			if (!(val & 0x80808080)) {
				val &= ~0x20202020;
				hash_value(val);
				name += sizeof(val);
				size -= sizeof(val);
				continue;
			}
		}

		while (!((c = *name) & 0x80)) {
			hash_value(c & ~0x20);
			name++;
			if (!--size)
				goto done:
		}

		do {
			// TODO: add denormalization for Mac
			unsigned val = towupper (utf8_to_wchar(&name, &size));
			hash_value(val);
		} while (size && (*name & 0x80));

	} while (size);
done:
	if (hp)
		final(a,b,c);
	return hs[2];
}

<irony>Oh yes, let's take this one, it is so much shorter, cleaner and 
overall more elegant than Linus' code.</irony>

Ciao,
Dscho