pqc/external/libtompoly-0.04/pb_grow.c

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2014-04-14 20:22:07 +00:00
/* LibTomPoly, Polynomial Basis Math -- Tom St Denis
*
* LibTomPoly is a public domain library that provides
* polynomial basis arithmetic support. It relies on
* LibTomMath for large integer support.
*
* This library is free for all purposes without any
* express guarantee that it works.
*
* Tom St Denis, tomstdenis@iahu.ca, http://poly.libtomcrypt.org
*/
#include <tompoly.h>
int pb_grow(pb_poly *a, int size)
{
mp_int *tmp;
int x, err;
if (a->alloc < size) {
/* pad size upwards */
size += (PB_TERMS - (size % PB_TERMS));
/* regrow terms */
tmp = realloc(a->terms, sizeof(mp_int) * size);
if (tmp == NULL) {
return MP_MEM;
}
a->terms = tmp;
/* zero the new stuff (prevents mp_clear from double freeing) */
memset(a->terms + a->alloc, 0, (size - a->alloc) * sizeof(mp_int));
/* now init the terms */
for (x = a->alloc; x < size; x++) {
if ((err = mp_init(&(a->terms[x]))) != MP_OKAY) {
return err;
}
}
/* update info */
a->alloc = size;
}
return MP_OKAY;
}