Mercurial > dropbear
view libtommath/bn_mp_fread.c @ 1682:a53e7d2d60be
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author | Matt Johnston <matt@ucc.asn.au> |
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date | Mon, 25 May 2020 20:23:02 +0800 |
parents | f52919ffd3b1 |
children | 1051e4eea25a |
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#include "tommath_private.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. * * SPDX-License-Identifier: Unlicense */ #ifndef LTM_NO_FILE /* read a bigint from a file stream in ASCII */ int mp_fread(mp_int *a, int radix, FILE *stream) { int err, ch, neg, y; unsigned pos; /* clear a */ mp_zero(a); /* if first digit is - then set negative */ ch = fgetc(stream); if (ch == (int)'-') { neg = MP_NEG; ch = fgetc(stream); } else { neg = MP_ZPOS; } for (;;) { 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; } ch = fgetc(stream); } if (mp_cmp_d(a, 0uL) != MP_EQ) { a->sign = neg; } return MP_OKAY; } #endif #endif /* ref: HEAD -> master, tag: v1.1.0 */ /* git commit: 08549ad6bc8b0cede0b357a9c341c5c6473a9c55 */ /* commit time: 2019-01-28 20:32:32 +0100 */