annotate bn_mp_fread.c @ 202:d7f5a681fa23 libtommath

Update Makefile.in for dropbear
author Matt Johnston <matt@ucc.asn.au>
date Wed, 11 May 2005 16:25:34 +0000
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d29b64170cf0 import of libtommath 0.32
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1 #include <tommath.h>
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2 #ifdef BN_MP_FREAD_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 /* read a bigint from a file stream in ASCII */
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19 int mp_fread(mp_int *a, int radix, FILE *stream)
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20 {
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21 int err, ch, neg, y;
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22
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23 /* clear a */
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24 mp_zero(a);
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25
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26 /* if first digit is - then set negative */
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27 ch = fgetc(stream);
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28 if (ch == '-') {
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29 neg = MP_NEG;
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30 ch = fgetc(stream);
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31 } else {
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32 neg = MP_ZPOS;
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33 }
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34
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35 for (;;) {
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36 /* find y in the radix map */
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37 for (y = 0; y < radix; y++) {
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38 if (mp_s_rmap[y] == ch) {
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39 break;
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40 }
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41 }
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42 if (y == radix) {
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43 break;
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44 }
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45
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46 /* shift up and add */
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47 if ((err = mp_mul_d(a, radix, a)) != MP_OKAY) {
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48 return err;
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49 }
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50 if ((err = mp_add_d(a, y, a)) != MP_OKAY) {
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51 return err;
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52 }
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53
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54 ch = fgetc(stream);
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55 }
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56 if (mp_cmp_d(a, 0) != MP_EQ) {
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57 a->sign = neg;
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58 }
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59
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60 return MP_OKAY;
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61 }
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62
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63 #endif