1 /* $NetBSD: bn_mp_fread.c,v 1.1.1.1 2011/04/13 18:14:54 elric Exp $ */ 2 3 #include <tommath.h> 4 #ifdef BN_MP_FREAD_C 5 /* LibTomMath, multiple-precision integer library -- Tom St Denis 6 * 7 * LibTomMath is a library that provides multiple-precision 8 * integer arithmetic as well as number theoretic functionality. 9 * 10 * The library was designed directly after the MPI library by 11 * Michael Fromberger but has been written from scratch with 12 * additional optimizations in place. 13 * 14 * The library is free for all purposes without any express 15 * guarantee it works. 16 * 17 * Tom St Denis, tomstdenis@gmail.com, http://libtom.org 18 */ 19 20 /* read a bigint from a file stream in ASCII */ 21 int mp_fread(mp_int *a, int radix, FILE *stream) 22 { 23 int err, ch, neg, y; 24 25 /* clear a */ 26 mp_zero(a); 27 28 /* if first digit is - then set negative */ 29 ch = fgetc(stream); 30 if (ch == '-') { 31 neg = MP_NEG; 32 ch = fgetc(stream); 33 } else { 34 neg = MP_ZPOS; 35 } 36 37 for (;;) { 38 /* find y in the radix map */ 39 for (y = 0; y < radix; y++) { 40 if (mp_s_rmap[y] == ch) { 41 break; 42 } 43 } 44 if (y == radix) { 45 break; 46 } 47 48 /* shift up and add */ 49 if ((err = mp_mul_d(a, radix, a)) != MP_OKAY) { 50 return err; 51 } 52 if ((err = mp_add_d(a, y, a)) != MP_OKAY) { 53 return err; 54 } 55 56 ch = fgetc(stream); 57 } 58 if (mp_cmp_d(a, 0) != MP_EQ) { 59 a->sign = neg; 60 } 61 62 return MP_OKAY; 63 } 64 65 #endif 66 67 /* Source: /cvs/libtom/libtommath/bn_mp_fread.c,v */ 68 /* Revision: 1.4 */ 69 /* Date: 2006/12/28 01:25:13 */ 70