1 #include <tommath.h> 2 #ifdef BN_MP_READ_UNSIGNED_BIN_C 3 /* LibTomMath, multiple-precision integer library -- Tom St Denis 4 * 5 * LibTomMath is a library that provides multiple-precision 6 * integer arithmetic as well as number theoretic functionality. 7 * 8 * The library was designed directly after the MPI library by 9 * Michael Fromberger but has been written from scratch with 10 * additional optimizations in place. 11 * 12 * The library is free for all purposes without any express 13 * guarantee it works. 14 * 15 * Tom St Denis, tomstdenis (at) gmail.com, http://math.libtomcrypt.com 16 */ 17 18 /* reads a unsigned char array, assumes the msb is stored first [big endian] */ 19 int mp_read_unsigned_bin (mp_int * a, const unsigned char *b, int c) 20 { 21 int res; 22 23 /* make sure there are at least two digits */ 24 if (a->alloc < 2) { 25 if ((res = mp_grow(a, 2)) != MP_OKAY) { 26 return res; 27 } 28 } 29 30 /* zero the int */ 31 mp_zero (a); 32 33 /* read the bytes in */ 34 while (c-- > 0) { 35 if ((res = mp_mul_2d (a, 8, a)) != MP_OKAY) { 36 return res; 37 } 38 39 #ifndef MP_8BIT 40 a->dp[0] |= *b++; 41 a->used += 1; 42 #else 43 a->dp[0] = (*b & MP_MASK); 44 a->dp[1] |= ((*b++ >> 7U) & 1); 45 a->used += 2; 46 #endif 47 } 48 mp_clamp (a); 49 return MP_OKAY; 50 } 51 #endif 52 53 /* $Source: /cvs/libtom/libtommath/bn_mp_read_unsigned_bin.c,v $ */ 54 /* $Revision: 1.4 $ */ 55 /* $Date: 2006/03/31 14:18:44 $ */ 56
