nostrdb

an unfairly fast embedded nostr database backed by lmdb
git clone git://jb55.com/nostrdb
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hash_u5.c (1136B)

      1 #include "../config.h"
      2 #include "ccan/endian/endian.h"
      3 #include "ccan/short_types/short_types.h"
      4 #include "hash_u5.h"
      5 #include <string.h>
      6 
      7 void hash_u5_init(struct hash_u5 *hu5, const char *hrp)
      8 {
      9     hu5->buf = 0;
     10     hu5->num_bits = 0;
     11     sha256_init(&hu5->hash);
     12     sha256_update(&hu5->hash, hrp, strlen(hrp));
     13 }
     14 
     15 void hash_u5(struct hash_u5 *hu5, const u8 *u5, size_t len)
     16 {
     17     size_t bits = len * 5;
     18 
     19     while (bits) {
     20         size_t n = 5;
     21 
     22         if (bits < n)
     23             n = bits;
     24 
     25         hu5->buf <<= n;
     26         hu5->buf |= (*u5 >> (5-n));
     27         bits -= n;
     28         hu5->num_bits += n;
     29 
     30         if (n == 5)
     31             u5++;
     32 
     33         if (hu5->num_bits >= 32) {
     34             be32 be32 = cpu_to_be32((u32)(hu5->buf >> (hu5->num_bits-32)));
     35             sha256_update(&hu5->hash, &be32, sizeof(be32));
     36             hu5->num_bits -= 32;
     37         }
     38     }
     39 }
     40 
     41 void hash_u5_done(struct hash_u5 *hu5, struct sha256 *res)
     42 {
     43     if (hu5->num_bits) {
     44         be32 be32 = cpu_to_be32((u32)(hu5->buf << (32 - hu5->num_bits)));
     45 
     46         sha256_update(&hu5->hash, &be32, (hu5->num_bits + 7) / 8);
     47     }
     48     sha256_done(&hu5->hash, res);
     49 }