Mercurial > dropbear
diff libtommath/bn_mp_fread.c @ 284:eed26cff980b
propagate from branch 'au.asn.ucc.matt.ltm.dropbear' (head 6c790cad5a7fa866ad062cb3a0c279f7ba788583)
to branch 'au.asn.ucc.matt.dropbear' (head fff0894a0399405a9410ea1c6d118f342cf2aa64)
author | Matt Johnston <matt@ucc.asn.au> |
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date | Wed, 08 Mar 2006 13:23:49 +0000 |
parents | |
children | 5ff8218bcee9 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/libtommath/bn_mp_fread.c Wed Mar 08 13:23:49 2006 +0000 @@ -0,0 +1,63 @@ +#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