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58 lines
1.5 KiB
C
58 lines
1.5 KiB
C
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#include <tommath.h>
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#ifdef BN_MP_GROW_C
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/* LibTomMath, multiple-precision integer library -- Tom St Denis
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*
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* LibTomMath is a library that provides multiple-precision
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* integer arithmetic as well as number theoretic functionality.
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*
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* The library was designed directly after the MPI library by
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* Michael Fromberger but has been written from scratch with
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* additional optimizations in place.
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*
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* The library is free for all purposes without any express
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* guarantee it works.
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*
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* Tom St Denis, tomstdenis@gmail.com, http://math.libtomcrypt.com
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*/
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/* grow as required */
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int mp_grow (mp_int * a, int size)
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{
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int i;
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mp_digit *tmp;
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/* if the alloc size is smaller alloc more ram */
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if (a->alloc < size) {
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/* ensure there are always at least MP_PREC digits extra on top */
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size += (MP_PREC * 2) - (size % MP_PREC);
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/* reallocate the array a->dp
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*
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* We store the return in a temporary variable
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* in case the operation failed we don't want
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* to overwrite the dp member of a.
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*/
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tmp = OPT_CAST(mp_digit) XREALLOC (a->dp, sizeof (mp_digit) * size);
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if (tmp == NULL) {
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/* reallocation failed but "a" is still valid [can be freed] */
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return MP_MEM;
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}
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/* reallocation succeeded so set a->dp */
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a->dp = tmp;
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/* zero excess digits */
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i = a->alloc;
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a->alloc = size;
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for (; i < a->alloc; i++) {
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a->dp[i] = 0;
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}
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}
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return MP_OKAY;
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}
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#endif
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/* $Source: /cvs/libtom/libtommath/bn_mp_grow.c,v $ */
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/* $Revision: 1.3 $ */
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/* $Date: 2006/03/31 14:18:44 $ */
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