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annotate libtommath/bn_mp_from_ubin.c @ 1730:57226fc75cb5

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Some notes on style
author Matt Johnston <matt@ucc.asn.au>
date Fri, 26 Jun 2020 20:41:34 +0800
parents 1051e4eea25a
children
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
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1692
1051e4eea25a Update LibTomMath to 1.2.0 (#84)
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1 #include "tommath_private.h"
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2 #ifdef BN_MP_FROM_UBIN_C
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3 /* LibTomMath, multiple-precision integer library -- Tom St Denis */
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4 /* SPDX-License-Identifier: Unlicense */
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5
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6 /* reads a unsigned char array, assumes the msb is stored first [big endian] */
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7 mp_err mp_from_ubin(mp_int *a, const unsigned char *buf, size_t size)
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8 {
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9 mp_err err;
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10
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11 /* make sure there are at least two digits */
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12 if (a->alloc < 2) {
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13 if ((err = mp_grow(a, 2)) != MP_OKAY) {
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14 return err;
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15 }
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16 }
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17
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18 /* zero the int */
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19 mp_zero(a);
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20
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21 /* read the bytes in */
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22 while (size-- > 0u) {
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23 if ((err = mp_mul_2d(a, 8, a)) != MP_OKAY) {
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24 return err;
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25 }
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26
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27 #ifndef MP_8BIT
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28 a->dp[0] |= *buf++;
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29 a->used += 1;
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30 #else
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31 a->dp[0] = (*buf & MP_MASK);
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32 a->dp[1] |= ((*buf++ >> 7) & 1u);
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33 a->used += 2;
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34 #endif
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35 }
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36 mp_clamp(a);
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37 return MP_OKAY;
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38 }
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39 #endif