44 lines
907 B
C
44 lines
907 B
C
#include "tommath_private.h"
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#ifdef MP_LOG_U32_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 mp_log_u32(const mp_int *a, uint32_t base, uint32_t *c)
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{
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if (a->sign == MP_NEG) {
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return MP_VAL;
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}
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if (MP_IS_ZERO(a)) {
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return MP_VAL;
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}
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if (base < 2u) {
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return MP_VAL;
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}
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/* A small shortcut for bases that are powers of two. */
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if ((base & (base - 1u)) == 0u) {
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int y, bit_count;
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for (y=0; (y < 7) && ((base & 1u) == 0u); y++) {
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base >>= 1;
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}
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bit_count = mp_count_bits(a) - 1;
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*c = (uint32_t)(bit_count/y);
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return MP_OKAY;
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}
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if (MP_HAS(S_MP_LOG_D) && (a->used == 1)) {
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*c = (uint32_t)s_mp_log_d(base, a->dp[0]);
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return MP_OKAY;
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}
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if (MP_HAS(S_MP_LOG)) {
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return s_mp_log(a, base, c);
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}
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return MP_VAL;
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}
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#endif
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