Mercurial > dropbear
view libtommath/bn_mp_fread.c @ 310:4b4478d0d2b9 ucc-axis-hack
add a comment on usage
author | Matt Johnston <matt@ucc.asn.au> |
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date | Sun, 26 Mar 2006 08:28:16 +0000 |
parents | eed26cff980b |
children | 5ff8218bcee9 |
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#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, [email protected], 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