Commit 3694dc5f authored by Timo Teräs's avatar Timo Teräs

fix murmur3 hash unaligned memory access

- do not do unaligned accesses on non-x86 hardware
- clean up the code a little bit
parent 6d11ec36
Pipeline #7634 passed with stage
in 49 seconds
......@@ -199,49 +199,59 @@ 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);
}
static uint32_t murmur3_32(const char *key, uint32_t len, uint32_t seed)
static inline uint32_t rotl32(uint32_t x, int8_t r)
{
return (x << r) | (x >> (32 - r));
}
static inline uint32_t get_unaligned32(const void *ptr)
{
#if defined(__x86_64__) || defined(__i386__)
return *(const uint32_t *)ptr;
#else
const uint8_t *p = ptr;
return p[0] | p[1] << 8 | p[2] << 16 | p[3] << 24;
#endif
}
static uint32_t murmur3_32(const void *pkey, 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 uint8_t *key = pkey;
const int nblocks = len / 4;
const uint32_t *blocks = (const uint32_t *) key;
uint32_t k, h = seed;
int i;
for (i = 0; i < nblocks; i++) {
uint32_t k = blocks[i];
for (i = 0; i < nblocks; i++, key += 4) {
k = get_unaligned32(key);
k *= c1;
k = (k << r1) | (k >> (32 - r1));
k = rotl32(k, 15);
k *= c2;
hash ^= k;
hash = ((hash << r2) | (hash >> (32 - r2))) * m + n;
h ^= k;
h = rotl32(h, 13) * 5 + 0xe6546b64;
}
const uint8_t *tail = (const uint8_t *) (key + nblocks * 4);
uint32_t k1 = 0;
k = 0;
switch (len & 3) {
case 3:
k1 ^= tail[2] << 16;
k ^= key[2] << 16;
case 2:
k1 ^= tail[1] << 8;
k ^= key[1] << 8;
case 1:
k1 ^= tail[0];
k1 *= c1;
k1 = (k1 << r1) | (k1 >> (32 - r1));
k1 *= c2;
hash ^= k1;
k ^= key[0];
k *= c1;
k = rotl32(k, 15);
k *= c2;
h ^= k;
}
hash ^= len;
hash ^= (hash >> 16);
hash *= 0x85ebca6b;
hash ^= (hash >> 13);
hash *= 0xc2b2ae35;
hash ^= (hash >> 16);
return hash;
h ^= len;
h ^= (h >> 16);
h *= 0x85ebca6b;
h ^= (h >> 13);
h *= 0xc2b2ae35;
h ^= (h >> 16);
return h;
}
unsigned long apk_blob_hash_seed(apk_blob_t blob, unsigned long seed)
......
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