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comparison libtommath/bn_mp_from_ubin.c @ 1692:1051e4eea25a

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Update LibTomMath to 1.2.0 (#84) * update C files * update other files * update headers * update makefiles * remove mp_set/get_double() * use ltm 1.2.0 API * update ltm_desc * use bundled tommath if system-tommath is too old * XMALLOC etc. were changed to MP_MALLOC etc.
author Steffen Jaeckel <s@jaeckel.eu>
date Tue, 26 May 2020 17:36:47 +0200
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1691:2d3745d58843 1692:1051e4eea25a
1 #include "tommath_private.h"
2 #ifdef BN_MP_FROM_UBIN_C
3 /* LibTomMath, multiple-precision integer library -- Tom St Denis */
4 /* SPDX-License-Identifier: Unlicense */
5
6 /* reads a unsigned char array, assumes the msb is stored first [big endian] */
7 mp_err mp_from_ubin(mp_int *a, const unsigned char *buf, size_t size)
8 {
9 mp_err err;
10
11 /* make sure there are at least two digits */
12 if (a->alloc < 2) {
13 if ((err = mp_grow(a, 2)) != MP_OKAY) {
14 return err;
15 }
16 }
17
18 /* zero the int */
19 mp_zero(a);
20
21 /* read the bytes in */
22 while (size-- > 0u) {
23 if ((err = mp_mul_2d(a, 8, a)) != MP_OKAY) {
24 return err;
25 }
26
27 #ifndef MP_8BIT
28 a->dp[0] |= *buf++;
29 a->used += 1;
30 #else
31 a->dp[0] = (*buf & MP_MASK);
32 a->dp[1] |= ((*buf++ >> 7) & 1u);
33 a->used += 2;
34 #endif
35 }
36 mp_clamp(a);
37 return MP_OKAY;
38 }
39 #endif