iw7-mod/deps/libtommath/mp_hash.c

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2024-08-13 05:15:34 -04:00
#include "tommath_private.h"
#ifdef MP_HASH_C
/* LibTomMath, multiple-precision integer library -- Tom St Denis */
/* SPDX-License-Identifier: Unlicense */
#if defined(MP_16BIT)
#define FNV_1A_INIT ((uint32_t)0x811c9dc5)
#define FNV_1A_PRIME ((uint32_t)0x01000193)
#else
#define FNV_1A_INIT ((uint64_t)0xcbf29ce484222325ULL)
#define FNV_1A_PRIME ((uint64_t)0x100000001b3ULL)
#endif
/* computes hash of mp_int. */
mp_err mp_hash(const mp_int *a, mp_hval *hash)
{
int x;
mp_hval hval = FNV_1A_INIT;
mp_digit r, mask, shift;
/* FNV-1a algorithm */
mask = ((mp_digit)1 << 8) - 1uL;
shift = (mp_digit)(MP_DIGIT_BIT - 8);
r = 0;
for (x = a->used; x --> 0;) {
mp_digit rr = a->dp[x] & mask;
hval ^= (mp_hval)(a->dp[x] >> 8) | (r << shift);
hval *= FNV_1A_PRIME;
r = rr;
}
hval ^= mp_isneg(a) ? (mp_hval)1 : (mp_hval)0;
*hash = hval * FNV_1A_PRIME;
return MP_OKAY;
}
#endif