pb_shrink.c

   1 /* LibTomPoly, Polynomial Basis Math -- Tom St Denis
   2  *
   3  * LibTomPoly is a public domain library that provides
   4  * polynomial basis arithmetic support.  It relies on
   5  * LibTomMath for large integer support.
   6  *
   7  * This library is free for all purposes without any
   8  * express guarantee that it works.
   9  *
  10  * Tom St Denis, tomstdenis@iahu.ca, http://poly.libtomcrypt.org
  11  */
  12 #include <tompoly.h>
  13 #include <stdlib.h>
  14
  15 int pb_shrink(pb_poly *a)
  16 {
  17    int err, x;
  18    mp_int *tmp;
  19
  20    /* first resize the array of terms */
  21    if (a->used != a->alloc && a->used > 0) {
  22       /* free the mp_ints */
  23       for (x = a->used; x < a->alloc; x++) {
  24           mp_clear(&(a->terms[x]));
  25       }
  26
  27       /* resize the array of pointers */
  28       tmp = realloc(a->terms, sizeof(mp_int) * a->used);
  29       if (tmp == NULL) {
  30          return MP_MEM;
  31       }
  32       a->terms = tmp;
  33       a->alloc = a->used;
  34    }
  35
  36    /* now shrink each mp_int */
  37    for (x = 0; x < a->used; x++) {
  38        if ((err = mp_shrink(&(a->terms[x]))) != MP_OKAY) {
  39           return err;
  40        }
  41    }
  42    return MP_OKAY;
  43 }
  44
  45