diff options
Diffstat (limited to 'src/blob.c')
| -rw-r--r-- | src/blob.c | 51 |
1 files changed, 45 insertions, 6 deletions
@@ -200,17 +200,56 @@ apk_blob_t apk_blob_pushed(apk_blob_t buffer, apk_blob_t left) return APK_BLOB_PTR_LEN(buffer.ptr, left.ptr - buffer.ptr); } -unsigned long apk_blob_hash_seed(apk_blob_t blob, unsigned long seed) -{ - unsigned long hash = seed; +static uint32_t murmur3_32(const char *key, uint32_t len, uint32_t seed) +{ + static const uint32_t c1 = 0xcc9e2d51; + static const uint32_t c2 = 0x1b873593; + static const uint32_t r1 = 15; + static const uint32_t r2 = 13; + static const uint32_t m = 5; + static const uint32_t n = 0xe6546b64; + uint32_t hash = seed; + const int nblocks = len / 4; + const uint32_t *blocks = (const uint32_t *) key; int i; + for (i = 0; i < nblocks; i++) { + uint32_t k = blocks[i]; + k *= c1; + k = (k << r1) | (k >> (32 - r1)); + k *= c2; + hash ^= k; + hash = ((hash << r2) | (hash >> (32 - r2))) * m + n; + } - for (i = 0; i < blob.len; i++) - hash = hash * 33 + blob.ptr[i]; - + const uint8_t *tail = (const uint8_t *) (key + nblocks * 4); + uint32_t k1 = 0; + + switch (len & 3) { + case 3: + k1 ^= tail[2] << 16; + case 2: + k1 ^= tail[1] << 8; + case 1: + k1 ^= tail[0]; + k1 *= c1; + k1 = (k1 << r1) | (k1 >> (32 - r1)); + k1 *= c2; + hash ^= k1; + } + hash ^= len; + hash ^= (hash >> 16); + hash *= 0x85ebca6b; + hash ^= (hash >> 13); + hash *= 0xc2b2ae35; + hash ^= (hash >> 16); return hash; } +unsigned long apk_blob_hash_seed(apk_blob_t blob, unsigned long seed) +{ + return murmur3_32(blob.ptr, blob.len, seed); +} + unsigned long apk_blob_hash(apk_blob_t blob) { return apk_blob_hash_seed(blob, 5381); |