Commit | Line | Data |
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41177ed3 JA |
1 | #include "fnv.h" |
2 | ||
3 | #define FNV_PRIME 0x100000001b3ULL | |
4 | ||
855f0362 JA |
5 | /* |
6 | * 64-bit fnv, but don't require 64-bit multiples of data. Use bytes | |
7 | * for the last unaligned chunk. | |
8 | */ | |
41177ed3 JA |
9 | uint64_t fnv(const void *buf, uint32_t len, uint64_t hval) |
10 | { | |
11 | const uint64_t *ptr = buf; | |
41177ed3 | 12 | |
855f0362 | 13 | while (len) { |
41177ed3 | 14 | hval *= FNV_PRIME; |
855f0362 JA |
15 | if (len >= sizeof(uint64_t)) { |
16 | hval ^= (uint64_t) *ptr++; | |
17 | len -= sizeof(uint64_t); | |
18 | continue; | |
19 | } else { | |
20 | const uint8_t *ptr8 = (const uint8_t *) ptr; | |
21 | uint64_t val = 0; | |
22 | int i; | |
23 | ||
24 | for (i = 0; i < len; i++) { | |
25 | val <<= 8; | |
26 | val |= (uint8_t) *ptr8++; | |
27 | } | |
28 | hval ^= val; | |
29 | break; | |
30 | } | |
41177ed3 JA |
31 | } |
32 | ||
33 | return hval; | |
34 | } |