annotate bn_mp_to_unsigned_bin.c @ 282:91fbc376f010 libtommath-orig libtommath-0.35

Import of libtommath 0.35 From ltm-0.35.tar.bz2 SHA1 of 3f193dbae9351e92d02530994fa18236f7fde01c
author Matt Johnston <matt@ucc.asn.au>
date Wed, 08 Mar 2006 13:16:18 +0000
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children 97db060d0ef5
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1 #include <tommath.h>
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2 #ifdef BN_MP_TO_UNSIGNED_BIN_C
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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 /* store in unsigned [big endian] format */
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19 int mp_to_unsigned_bin (mp_int * a, unsigned char *b)
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20 {
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21 int x, res;
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22 mp_int t;
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23
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24 if ((res = mp_init_copy (&t, a)) != MP_OKAY) {
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25 return res;
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26 }
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27
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28 x = 0;
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29 while (mp_iszero (&t) == 0) {
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30 #ifndef MP_8BIT
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31 b[x++] = (unsigned char) (t.dp[0] & 255);
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32 #else
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33 b[x++] = (unsigned char) (t.dp[0] | ((t.dp[1] & 0x01) << 7));
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34 #endif
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35 if ((res = mp_div_2d (&t, 8, &t, NULL)) != MP_OKAY) {
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36 mp_clear (&t);
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37 return res;
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38 }
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39 }
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40 bn_reverse (b, x);
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41 mp_clear (&t);
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42 return MP_OKAY;
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43 }
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44 #endif