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view libtommath/bn_mp_fread.c @ 1793:f90e681b8b8c
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author | Matt Johnston <matt@ucc.asn.au> |
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date | Fri, 29 Jan 2021 21:59:12 +0800 |
parents | 1051e4eea25a |
children |
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#include "tommath_private.h" #ifdef BN_MP_FREAD_C /* LibTomMath, multiple-precision integer library -- Tom St Denis */ /* SPDX-License-Identifier: Unlicense */ #ifndef MP_NO_FILE /* read a bigint from a file stream in ASCII */ mp_err mp_fread(mp_int *a, int radix, FILE *stream) { mp_err err; mp_sign neg; /* if first digit is - then set negative */ int ch = fgetc(stream); if (ch == (int)'-') { neg = MP_NEG; ch = fgetc(stream); } else { neg = MP_ZPOS; } /* no digits, return error */ if (ch == EOF) { return MP_ERR; } /* clear a */ mp_zero(a); do { int y; unsigned pos = (unsigned)(ch - (int)'('); if (mp_s_rmap_reverse_sz < pos) { break; } y = (int)mp_s_rmap_reverse[pos]; if ((y == 0xff) || (y >= radix)) { break; } /* shift up and add */ if ((err = mp_mul_d(a, (mp_digit)radix, a)) != MP_OKAY) { return err; } if ((err = mp_add_d(a, (mp_digit)y, a)) != MP_OKAY) { return err; } } while ((ch = fgetc(stream)) != EOF); if (a->used != 0) { a->sign = neg; } return MP_OKAY; } #endif #endif