Add implementation for the murmur3 x64_128 hash

src/base/hash/hasher/murmur3.c

@@ -0,0 +1,105 @@
+// vim:fileencoding=utf-8:foldmethod=marker
+
+#include "murmur3.h"
+#include "../../../common/aliases/aliases.h"
+#include "../../../common/misc/misc_utils.h"
+
+#define _bigConstant(x) (x##LLU)
+
+wp_intern inline u64 fmix64(u64 k);
+
+void wpX64Mur3Hasher128(WpU8Stream *bytes, void *hasher_io) {
+	WpMur3HasherIO *io = (WpMur3HasherIO *)hasher_io;
+
+	const i32 nblocks = (bytes->count * bytes->item_size) / 16;
+
+	u64 h1 = io->seed;
+	u64 h2 = io->seed;
+
+	const u64 c1 = _bigConstant(0x87c37b91114253d5);
+	const u64 c2 = _bigConstant(0x4cf5ad432745937f);
+
+	//----------
+	// body
+
+	for(int i = 0; i < nblocks; ++i) {
+		u64 k1 = *((u64 *)wpStreamConsumeCount(u8, bytes, sizeof(u64)));
+		u64 k2 = *((u64 *)wpStreamConsumeCount(u8, bytes, sizeof(u64)));
+
+		k1 *= c1;
+		k1  = wpMiscUtilsRotl64(k1, 31);
+		k1 *= c2;
+		h1 ^= k1;
+
+		h1  = wpMiscUtilsRotl64(h1, 27);
+		h1 += h2;
+		h1  = h1 * 5 +0x52dce729;
+
+		k2 *= c2;
+		k2  = wpMiscUtilsRotl64(k2, 33);
+		k2 *= c1;
+		h2 ^= k2;
+
+		h2  = wpMiscUtilsRotl64(h2, 31);
+		h2 += h1;
+		h2  = h2*5+0x38495ab5;
+	}
+
+	//----------
+	// tail
+
+	const u8 *tail = wpStreamConsumeCount(u8, bytes, bytes->count - bytes->position);
+
+	u64 k1 = 0;
+	u64 k2 = 0;
+
+	u64 len = bytes->count * bytes->item_size;
+
+	switch(len & 15) {
+		case 15: k2 ^= ((u64)tail[14]) << 48;
+		case 14: k2 ^= ((u64)tail[13]) << 40;
+		case 13: k2 ^= ((u64)tail[12]) << 32;
+		case 12: k2 ^= ((u64)tail[11]) << 24;
+		case 11: k2 ^= ((u64)tail[10]) << 16;
+		case 10: k2 ^= ((u64)tail[ 9]) << 8;
+		case  9: k2 ^= ((u64)tail[ 8]) << 0;
+		         k2 *= c2; k2  = wpMiscUtilsRotl64(k2,33); k2 *= c1; h2 ^= k2;
+
+		case  8: k1 ^= ((u64)tail[ 7]) << 56;
+		case  7: k1 ^= ((u64)tail[ 6]) << 48;
+		case  6: k1 ^= ((u64)tail[ 5]) << 40;
+		case  5: k1 ^= ((u64)tail[ 4]) << 32;
+		case  4: k1 ^= ((u64)tail[ 3]) << 24;
+		case  3: k1 ^= ((u64)tail[ 2]) << 16;
+		case  2: k1 ^= ((u64)tail[ 1]) << 8;
+		case  1: k1 ^= ((u64)tail[ 0]) << 0;
+		         k1 *= c1; k1  = wpMiscUtilsRotl64(k1,31); k1 *= c2; h1 ^= k1;
+	};
+
+	//----------
+	// finalization
+
+	h1 ^= len; h2 ^= len;
+
+	h1 += h2;
+	h2 += h1;
+
+	h1 = fmix64(h1);
+	h2 = fmix64(h2);
+
+	h1 += h2;
+	h2 += h1;
+
+	io->out_hash1 = h1;
+	io->out_hash2 = h2;
+}
+
+wp_intern inline u64 fmix64(u64 k) {
+	k ^= k >> 33;
+	k *= _bigConstant(0xff51afd7ed558ccd);
+	k ^= k >> 33;
+	k *= _bigConstant(0xc4ceb9fe1a85ec53);
+	k ^= k >> 33;
+
+	return k;
+}