40 lines
876 B
C
40 lines
876 B
C
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#include "tommath_private.h"
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#ifdef BN_MP_FROM_UBIN_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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/* reads a unsigned char array, assumes the msb is stored first [big endian] */
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mp_err mp_from_ubin(mp_int *a, const unsigned char *buf, size_t size)
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{
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mp_err err;
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/* make sure there are at least two digits */
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if (a->alloc < 2) {
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if ((err = mp_grow(a, 2)) != MP_OKAY) {
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return err;
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}
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}
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/* zero the int */
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mp_zero(a);
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/* read the bytes in */
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while (size-- > 0u) {
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if ((err = mp_mul_2d(a, 8, a)) != MP_OKAY) {
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return err;
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}
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#ifndef MP_8BIT
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a->dp[0] |= *buf++;
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a->used += 1;
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#else
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a->dp[0] = (*buf & MP_MASK);
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a->dp[1] |= ((*buf++ >> 7) & 1u);
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a->used += 2;
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#endif
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}
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mp_clamp(a);
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return MP_OKAY;
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}
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#endif
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