1 #include <tommath.h> 2 #ifdef BN_MP_GROW_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 /* grow as required */ 19 int mp_grow (mp_int * a, int size) 20 { 21 int i; 22 mp_digit *tmp; 23 24 /* if the alloc size is smaller alloc more ram */ 25 if (a->alloc < size) { 26 /* ensure there are always at least MP_PREC digits extra on top */ 27 size += (MP_PREC * 2) - (size % MP_PREC); 28 29 /* reallocate the array a->dp 30 * 31 * We store the return in a temporary variable 32 * in case the operation failed we don't want 33 * to overwrite the dp member of a. 34 */ 35 tmp = OPT_CAST(mp_digit) XREALLOC (a->dp, sizeof (mp_digit) * size); 36 if (tmp == NULL) { 37 /* reallocation failed but "a" is still valid [can be freed] */ 38 return MP_MEM; 39 } 40 41 /* reallocation succeeded so set a->dp */ 42 a->dp = tmp; 43 44 /* zero excess digits */ 45 i = a->alloc; 46 a->alloc = size; 47 for (; i < a->alloc; i++) { 48 a->dp[i] = 0; 49 } 50 } 51 return MP_OKAY; 52 } 53 #endif 54 55 /* $Source: /cvs/libtom/libtommath/bn_mp_grow.c,v $ */ 56 /* $Revision: 1.3 $ */ 57 /* $Date: 2006/03/31 14:18:44 $ */ 58
