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