| Line | Branch | Exec | Source |
|---|---|---|---|
| 1 | #ifndef UTIL_HASH_H | ||
| 2 | #define UTIL_HASH_H | ||
| 3 | |||
| 4 | #include <limits.h> | ||
| 5 | #include <stddef.h> | ||
| 6 | #include <stdint.h> | ||
| 7 | #include "ascii.h" | ||
| 8 | #include "macros.h" | ||
| 9 | |||
| 10 | 69048 | static inline size_t fnv_1a_init(void) | |
| 11 | { | ||
| 12 | 69048 | static_assert(8 * CHAR_BIT == 64); | |
| 13 | 69048 | return (sizeof(size_t) >= 8) ? 14695981039346656037ULL : 2166136261U; | |
| 14 | } | ||
| 15 | |||
| 16 | 69048 | static inline size_t fnv_1a_prime(void) | |
| 17 | { | ||
| 18 | 69048 | return (sizeof(size_t) >= 8) ? 1099511628211ULL : 16777619U; | |
| 19 | } | ||
| 20 | |||
| 21 | 66308 | static inline size_t fnv_1a_hash(const unsigned char *str, size_t n) | |
| 22 | { | ||
| 23 | 66308 | const size_t prime = fnv_1a_prime(); | |
| 24 | 66308 | size_t hash = fnv_1a_init(); | |
| 25 |
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494362 | while (n--) { |
| 26 | 428054 | hash ^= *str++; | |
| 27 | 428054 | hash *= prime; | |
| 28 | } | ||
| 29 | 66308 | return hash; | |
| 30 | } | ||
| 31 | |||
| 32 | 2740 | static inline size_t fnv_1a_hash_icase(const unsigned char *str, size_t n) | |
| 33 | { | ||
| 34 | 2740 | const size_t prime = fnv_1a_prime(); | |
| 35 | 2740 | size_t hash = fnv_1a_init(); | |
| 36 |
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29132 | while (n--) { |
| 37 | 26392 | hash ^= ascii_tolower(*str++); | |
| 38 | 26392 | hash *= prime; | |
| 39 | } | ||
| 40 | 2740 | return hash; | |
| 41 | } | ||
| 42 | |||
| 43 | // NOTE: returns 0 if x is greater than the largest size_t power of 2 | ||
| 44 | 425 | static inline size_t next_pow2(size_t x) | |
| 45 | { | ||
| 46 |
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425 | if (unlikely(x == 0)) { |
| 47 | return 1; | ||
| 48 | } | ||
| 49 | 424 | x--; | |
| 50 | UNROLL_LOOP(8) | ||
| 51 |
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2968 | for (size_t i = 1, n = sizeof(size_t) * CHAR_BIT; i < n; i <<= 1) { |
| 52 | 2544 | x |= x >> i; | |
| 53 | } | ||
| 54 | 424 | return x + 1; | |
| 55 | } | ||
| 56 | |||
| 57 | #endif | ||
| 58 |