| #include <tommath.h> |
| #ifdef BN_MP_FREAD_C |
| /* LibTomMath, multiple-precision integer library -- Tom St Denis |
| * |
| * LibTomMath is a library that provides multiple-precision |
| * integer arithmetic as well as number theoretic functionality. |
| * |
| * The library was designed directly after the MPI library by |
| * Michael Fromberger but has been written from scratch with |
| * additional optimizations in place. |
| * |
| * The library is free for all purposes without any express |
| * guarantee it works. |
| * |
| * Tom St Denis, tomstdenis@iahu.ca, http://math.libtomcrypt.org |
| */ |
| |
| /* read a bigint from a file stream in ASCII */ |
| int mp_fread(mp_int *a, int radix, FILE *stream) |
| { |
| int err, ch, neg, y; |
| |
| /* clear a */ |
| mp_zero(a); |
| |
| /* if first digit is - then set negative */ |
| ch = fgetc(stream); |
| if (ch == '-') { |
| neg = MP_NEG; |
| ch = fgetc(stream); |
| } else { |
| neg = MP_ZPOS; |
| } |
| |
| for (;;) { |
| /* find y in the radix map */ |
| for (y = 0; y < radix; y++) { |
| if (mp_s_rmap[y] == ch) { |
| break; |
| } |
| } |
| if (y == radix) { |
| break; |
| } |
| |
| /* shift up and add */ |
| if ((err = mp_mul_d(a, radix, a)) != MP_OKAY) { |
| return err; |
| } |
| if ((err = mp_add_d(a, y, a)) != MP_OKAY) { |
| return err; |
| } |
| |
| ch = fgetc(stream); |
| } |
| if (mp_cmp_d(a, 0) != MP_EQ) { |
| a->sign = neg; |
| } |
| |
| return MP_OKAY; |
| } |
| |
| #endif |