1 /* $NetBSD: bn_mp_read_unsigned_bin.c,v 1.1.1.2 2014/04/24 12:45:31 pettai Exp $ */ 2 3 #include <tommath.h> 4 #ifdef BN_MP_READ_UNSIGNED_BIN_C 5 /* LibTomMath, multiple-precision integer library -- Tom St Denis 6 * 7 * LibTomMath is a library that provides multiple-precision 8 * integer arithmetic as well as number theoretic functionality. 9 * 10 * The library was designed directly after the MPI library by 11 * Michael Fromberger but has been written from scratch with 12 * additional optimizations in place. 13 * 14 * The library is free for all purposes without any express 15 * guarantee it works. 16 * 17 * Tom St Denis, tomstdenis@gmail.com, http://libtom.org 18 */ 19 20 /* reads a unsigned char array, assumes the msb is stored first [big endian] */ 21 int mp_read_unsigned_bin (mp_int * a, const unsigned char *b, int c) 22 { 23 int res; 24 25 /* make sure there are at least two digits */ 26 if (a->alloc < 2) { 27 if ((res = mp_grow(a, 2)) != MP_OKAY) { 28 return res; 29 } 30 } 31 32 /* zero the int */ 33 mp_zero (a); 34 35 /* read the bytes in */ 36 while (c-- > 0) { 37 if ((res = mp_mul_2d (a, 8, a)) != MP_OKAY) { 38 return res; 39 } 40 41 #ifndef MP_8BIT 42 a->dp[0] |= *b++; 43 a->used += 1; 44 #else 45 a->dp[0] = (*b & MP_MASK); 46 a->dp[1] |= ((*b++ >> 7U) & 1); 47 a->used += 2; 48 #endif 49 } 50 mp_clamp (a); 51 return MP_OKAY; 52 } 53 #endif 54 55 /* Source: /cvs/libtom/libtommath/bn_mp_read_unsigned_bin.c,v */ 56 /* Revision: 1.5 */ 57 /* Date: 2006/12/28 01:25:13 */ 58