libtommath/mp_grow.c
Daniel Mendler 795cd2013f
simplifications: add s_mp_zero_(digs|buf) and s_mp_copy_digs
Originally I made those as macros. However we have many
other small functions like mp_clamp, mp_exch which are also not implemented
as macros right now.

If we would use c99, I would implement them as private static inline
functions. And mp_exch would be a public static inline function.

But since we are bound to c89, we simply use normal functions.
To achieve optimal performance one should either use link time
optimization or amalgamation.
2019-11-04 15:41:32 +01:00

35 lines
1.0 KiB
C

#include "tommath_private.h"
#ifdef MP_GROW_C
/* LibTomMath, multiple-precision integer library -- Tom St Denis */
/* SPDX-License-Identifier: Unlicense */
/* grow as required */
mp_err mp_grow(mp_int *a, int size)
{
/* if the alloc size is smaller alloc more ram */
if (a->alloc < size) {
/* 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.
*/
mp_digit *dp = (mp_digit *) MP_REALLOC(a->dp,
(size_t)a->alloc * sizeof(mp_digit),
(size_t)size * sizeof(mp_digit));
if (dp == NULL) {
/* reallocation failed but "a" is still valid [can be freed] */
return MP_MEM;
}
/* reallocation succeeded so set a->dp */
a->dp = dp;
/* zero excess digits */
s_mp_zero_digs(a->dp + a->alloc, size - a->alloc);
a->alloc = size;
}
return MP_OKAY;
}
#endif