Mercurial > dropbear
view bn_mp_grow.c @ 163:8e94663164c6 libtommath LTM_DB_0.44
make pointers volatile so that memory zeroing won't get optimised away
author | Matt Johnston <matt@ucc.asn.au> |
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date | Sun, 02 Jan 2005 17:09:26 +0000 |
parents | d29b64170cf0 |
children |
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#include <tommath.h> #ifdef BN_MP_GROW_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, [email protected], http://math.libtomcrypt.org */ /* grow as required */ int mp_grow (mp_int * a, int size) { int i; mp_digit *tmp; /* if the alloc size is smaller alloc more ram */ if (a->alloc < size) { /* ensure there are always at least MP_PREC digits extra on top */ size += (MP_PREC * 2) - (size % MP_PREC); /* reallocate the array a->dp * * We store the return in a temporary variable * in case the operation failed we don't want * to overwrite the dp member of a. */ tmp = OPT_CAST(mp_digit) XREALLOC (a->dp, sizeof (mp_digit) * size); if (tmp == NULL) { /* reallocation failed but "a" is still valid [can be freed] */ return MP_MEM; } /* reallocation succeeded so set a->dp */ a->dp = tmp; /* zero excess digits */ i = a->alloc; a->alloc = size; for (; i < a->alloc; i++) { a->dp[i] = 0; } } return MP_OKAY; } #endif