Improve performance of tokenization and parsing

1 files changed, 33 insertions, 0 deletions

diff --git a/src/murmurhash3.cpp b/src/murmurhash3.cpp
index ff51cf733..7465fac18 100644
--- a/src/murmurhash3.cpp
+++ b/src/murmurhash3.cpp
@@ -223,3 +223,36 @@ void MurmurHash3_x86_128(void const *key, isize len, u32 seed, void *out) {
 // }
 
 
+
+
+gb_internal gb_inline u32 murmur_32_scramble(u32 k) {
+	k *= 0xcc9e2d51;
+	k = (k << 15) | (k >> 17);
+	k *= 0x1b873593;
+	return k;
+}
+
+u32 murmur3_32(u8 const *key, isize len, u32 seed) {
+	u32 h = seed;
+	u32 k;
+	for (size_t i = len >> 2; i; i--) {
+		memcpy(&k, key, sizeof(u32));
+		key += sizeof(u32);
+		h ^= murmur_32_scramble(k);
+		h = (h << 13) | (h >> 19);
+		h = h * 5 + 0xe6546b64;
+	}
+	k = 0;
+	for (size_t i = len & 3; i; i--) {
+		k <<= 8;
+		k |= key[i - 1];
+	}
+	h ^= murmur_32_scramble(k);
+	h ^= len;
+	h ^= h >> 16;
+	h *= 0x85ebca6b;
+	h ^= h >> 13;
+	h *= 0xc2b2ae35;
+	h ^= h >> 16;
+	return h;
+}