Mercurial > dropbear
diff bn_mp_read_signed_bin.c @ 282:91fbc376f010 libtommath-orig libtommath-0.35
Import of libtommath 0.35
From ltm-0.35.tar.bz2 SHA1 of 3f193dbae9351e92d02530994fa18236f7fde01c
author | Matt Johnston <matt@ucc.asn.au> |
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date | Wed, 08 Mar 2006 13:16:18 +0000 |
parents | |
children | 97db060d0ef5 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/bn_mp_read_signed_bin.c Wed Mar 08 13:16:18 2006 +0000 @@ -0,0 +1,38 @@ +#include <tommath.h> +#ifdef BN_MP_READ_SIGNED_BIN_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 signed bin, big endian, first byte is 0==positive or 1==negative */ +int +mp_read_signed_bin (mp_int * a, unsigned char *b, int c) +{ + int res; + + /* read magnitude */ + if ((res = mp_read_unsigned_bin (a, b + 1, c - 1)) != MP_OKAY) { + return res; + } + + /* first byte is 0 for positive, non-zero for negative */ + if (b[0] == 0) { + a->sign = MP_ZPOS; + } else { + a->sign = MP_NEG; + } + + return MP_OKAY; +} +#endif