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Diffstat (limited to 'libtommath/bn_mp_read_signed_bin.c')
-rw-r--r-- | libtommath/bn_mp_read_signed_bin.c | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/libtommath/bn_mp_read_signed_bin.c b/libtommath/bn_mp_read_signed_bin.c new file mode 100644 index 0000000..e3df3c3 --- /dev/null +++ b/libtommath/bn_mp_read_signed_bin.c @@ -0,0 +1,41 @@ +#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, tomstdenis@gmail.com, http://math.libtomcrypt.com + */ + +/* read signed bin, big endian, first byte is 0==positive or 1==negative */ +int mp_read_signed_bin (mp_int * a, const 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 + +/* $Source: /cvs/libtom/libtommath/bn_mp_read_signed_bin.c,v $ */ +/* $Revision: 1.4 $ */ +/* $Date: 2006/03/31 14:18:44 $ */ |