annotate bn_mp_read_unsigned_bin.c @ 145:a96ff234ff19 libtommath

propagate of fc94c38452d9fd684a8e1eb9e3a73120aac0d38f and 3e4de4cbef3d9035a7b2f0c25e9f86e297f9f6d1 from branch 'au.asn.ucc.matt.ltm-orig' to 'au.asn.ucc.matt.ltm-db'
author Matt Johnston <matt@ucc.asn.au>
date Sun, 19 Dec 2004 15:57:19 +0000
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children
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1 #include <tommath.h>
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2 #ifdef BN_MP_READ_UNSIGNED_BIN_C
2
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3 /* LibTomMath, multiple-precision integer library -- Tom St Denis
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4 *
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5 * LibTomMath is a library that provides multiple-precision
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6 * integer arithmetic as well as number theoretic functionality.
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7 *
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8 * The library was designed directly after the MPI library by
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9 * Michael Fromberger but has been written from scratch with
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10 * additional optimizations in place.
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11 *
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12 * The library is free for all purposes without any express
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13 * guarantee it works.
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14 *
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15 * Tom St Denis, [email protected], http://math.libtomcrypt.org
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16 */
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17
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18 /* reads a unsigned char array, assumes the msb is stored first [big endian] */
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19 int
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20 mp_read_unsigned_bin (mp_int * a, unsigned char *b, int c)
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21 {
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22 int res;
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23
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24 /* make sure there are at least two digits */
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25 if (a->alloc < 2) {
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26 if ((res = mp_grow(a, 2)) != MP_OKAY) {
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27 return res;
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28 }
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29 }
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30
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31 /* zero the int */
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32 mp_zero (a);
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33
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34 /* read the bytes in */
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35 while (c-- > 0) {
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36 if ((res = mp_mul_2d (a, 8, a)) != MP_OKAY) {
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37 return res;
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38 }
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39
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40 #ifndef MP_8BIT
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41 a->dp[0] |= *b++;
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42 a->used += 1;
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43 #else
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44 a->dp[0] = (*b & MP_MASK);
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45 a->dp[1] |= ((*b++ >> 7U) & 1);
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46 a->used += 2;
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47 #endif
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48 }
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49 mp_clamp (a);
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50 return MP_OKAY;
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51 }
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d29b64170cf0 import of libtommath 0.32
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52 #endif