47 lines
1.0 KiB
C
47 lines
1.0 KiB
C
#include "tommath_private.h"
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#ifdef BN_MP_RAND_C
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/* LibTomMath, multiple-precision integer library -- Tom St Denis */
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/* SPDX-License-Identifier: Unlicense */
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mp_err(*s_mp_rand_source)(void *out, size_t size) = s_mp_rand_platform;
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void mp_rand_source(mp_err(*source)(void *out, size_t size))
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{
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s_mp_rand_source = (source == NULL) ? s_mp_rand_platform : source;
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}
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mp_err mp_rand(mp_int *a, int digits)
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{
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int i;
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mp_err err;
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mp_zero(a);
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if (digits <= 0) {
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return MP_OKAY;
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}
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if ((err = mp_grow(a, digits)) != MP_OKAY) {
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return err;
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}
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if ((err = s_mp_rand_source(a->dp, (size_t)digits * sizeof(mp_digit))) != MP_OKAY) {
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return err;
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}
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/* TODO: We ensure that the highest digit is nonzero. Should this be removed? */
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while ((a->dp[digits - 1] & MP_MASK) == 0u) {
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if ((err = s_mp_rand_source(a->dp + digits - 1, sizeof(mp_digit))) != MP_OKAY) {
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return err;
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}
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}
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a->used = digits;
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for (i = 0; i < digits; ++i) {
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a->dp[i] &= MP_MASK;
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}
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return MP_OKAY;
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}
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#endif
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