diff options
Diffstat (limited to 'src/libtommath/bn_mp_read_unsigned_bin.c')
-rw-r--r-- | src/libtommath/bn_mp_read_unsigned_bin.c | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/src/libtommath/bn_mp_read_unsigned_bin.c b/src/libtommath/bn_mp_read_unsigned_bin.c new file mode 100644 index 0000000..7d35370 --- /dev/null +++ b/src/libtommath/bn_mp_read_unsigned_bin.c @@ -0,0 +1,55 @@ +#include "tommath.h" +#ifdef BN_MP_READ_UNSIGNED_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://libtom.org + */ + +/* reads a unsigned char array, assumes the msb is stored first [big endian] */ +int mp_read_unsigned_bin (mp_int * a, const unsigned char *b, int c) +{ + int res; + + /* make sure there are at least two digits */ + if (a->alloc < 2) { + if ((res = mp_grow(a, 2)) != MP_OKAY) { + return res; + } + } + + /* zero the int */ + mp_zero (a); + + /* read the bytes in */ + while (c-- > 0) { + if ((res = mp_mul_2d (a, 8, a)) != MP_OKAY) { + return res; + } + +#ifndef MP_8BIT + a->dp[0] |= *b++; + a->used += 1; +#else + a->dp[0] = (*b & MP_MASK); + a->dp[1] |= ((*b++ >> 7U) & 1); + a->used += 2; +#endif + } + mp_clamp (a); + return MP_OKAY; +} +#endif + +/* $Source: /cvs/libtom/libtommath/bn_mp_read_unsigned_bin.c,v $ */ +/* $Revision: 1.5 $ */ +/* $Date: 2006/12/28 01:25:13 $ */ |