fzy

terminal fuzzy finder picker
theft_hash.c

(1181B)
      1 #include "theft.h"
      2 
      3 /* Fowler/Noll/Vo hash, 64-bit FNV-1a.
      4  * This hashing algorithm is in the public domain.
      5  * For more details, see: http://www.isthe.com/chongo/tech/comp/fnv/. */
      6 static const uint64_t fnv64_prime = 1099511628211L;
      7 static const uint64_t fnv64_offset_basis = 14695981039346656037UL;
      8 
      9 /* Init a hasher for incremental hashing. */
     10 void theft_hash_init(struct theft_hasher *h) {
     11     h->accum = fnv64_offset_basis;
     12 }
     13 
     14 /* Sink more data into an incremental hash. */
     15 void theft_hash_sink(struct theft_hasher *h, uint8_t *data, size_t bytes) {
     16     if (h == NULL || data == NULL) { return; }
     17     uint64_t a = h->accum;
     18     for (size_t i = 0; i < bytes; i++) {
     19         a = (a ^ data[i]) * fnv64_prime;
     20     }
     21     h->accum = a;
     22 }
     23 
     24 /* Finish hashing and get the result. */
     25 theft_hash theft_hash_done(struct theft_hasher *h) {
     26     theft_hash res = h->accum;
     27     theft_hash_init(h);                /* reset */
     28     return res;
     29 }
     30 
     31 /* Hash a buffer in one pass. (Wraps the above functions.) */
     32 theft_hash theft_hash_onepass(uint8_t *data, size_t bytes) {
     33     struct theft_hasher h;
     34     theft_hash_init(&h);
     35     theft_hash_sink(&h, data, bytes);
     36     return theft_hash_done(&h);
     37 }