Mercurial > dropbear

annotate libtommath/bn_mp_toradix.c @ 404:a588558bfc94

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Fix potential null pointer dereference found by Klokwork
author Matt Johnston <matt@ucc.asn.au>
date Sat, 03 Feb 2007 09:58:14 +0000
parents eed26cff980b
children 5ff8218bcee9
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
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284
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1 #include <tommath.h>
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2 #ifdef BN_MP_TORADIX_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 /* stores a bignum as a ASCII string in a given radix (2..64) */
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19 int mp_toradix (mp_int * a, char *str, int radix)
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20 {
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21 int res, digs;
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22 mp_int t;
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23 mp_digit d;
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24 char *_s = str;
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25
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26 /* check range of the radix */
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27 if (radix < 2 || radix > 64) {
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28 return MP_VAL;
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29 }
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30
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31 /* quick out if its zero */
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32 if (mp_iszero(a) == 1) {
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33 *str++ = '0';
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34 *str = '\0';
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35 return MP_OKAY;
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36 }
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37
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38 if ((res = mp_init_copy (&t, a)) != MP_OKAY) {
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39 return res;
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40 }
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41
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42 /* if it is negative output a - */
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43 if (t.sign == MP_NEG) {
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44 ++_s;
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45 *str++ = '-';
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46 t.sign = MP_ZPOS;
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47 }
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48
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49 digs = 0;
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50 while (mp_iszero (&t) == 0) {
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51 if ((res = mp_div_d (&t, (mp_digit) radix, &t, &d)) != MP_OKAY) {
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52 mp_clear (&t);
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53 return res;
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54 }
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55 *str++ = mp_s_rmap[d];
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56 ++digs;
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57 }
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58
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59 /* reverse the digits of the string. In this case _s points
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60 * to the first digit [exluding the sign] of the number]
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61 */
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62 bn_reverse ((unsigned char *)_s, digs);
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63
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64 /* append a NULL so the string is properly terminated */
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65 *str = '\0';
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66
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67 mp_clear (&t);
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68 return MP_OKAY;
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69 }
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70
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71 #endif