pb_init_size.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 /* initialize a */
  16 int pb_init_size(pb_poly *a, mp_int *characteristic, int size)
  17 {
  18    int x, y, err;
  19
  20    /* enforce a minimum size */
  21    if (size < 1) {
  22       size = 1;
  23    }
  24
  25    /* pad size upwards */
  26    size += (PB_TERMS - (size % PB_TERMS));
  27
  28
  29    /* init characteristic */
  30    if ((err = mp_init_copy(&(a->characteristic), characteristic)) != MP_OKAY) {
  31       return err;
  32    }
  33
  34    /* now allocate an array of mp_ints */
  35    if ((a->terms = calloc(size, sizeof(mp_int))) == NULL) {
  36       mp_clear(&(a->characteristic));
  37       return MP_MEM;
  38    }
  39
  40    /* now initialize them all */
  41    for (x = 0; x < size; x++) {
  42        if ((err = mp_init(&(a->terms[x]))) != MP_OKAY) {
  43           /* free stuff */
  44           for (y = 0; y < x; y++) {
  45               mp_clear(&(a->terms[y]));
  46           }
  47           free(a->terms);
  48           mp_clear(&(a->characteristic));
  49           return err;
  50       }
  51    }
  52
  53    /* set our parameters */
  54    a->used  = 0;
  55    a->alloc = size;
  56    return MP_OKAY;
  57 }
  58
  59