pb_toraw.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 int pb_toraw(pb_poly *a, unsigned char *dst)
  15 {
  16    int err, x, y, z;
  17
  18    /* store the # of terms */
  19    dst[0] = a->used & 255;
  20    dst[1] = (a->used >> 8) & 255;
  21    y      = 2;
  22
  23    /* store the characteristic */
  24    z = mp_signed_bin_size(&(a->characteristic));
  25    dst[y++] = z&255;
  26    dst[y++] = (z>>8)&255;
  27    if ((err = mp_to_signed_bin(&(a->characteristic), dst+y)) != MP_OKAY)          { return err; }
  28    y += z;
  29
  30    for (x = 0; x < a->used; x++) {
  31       z = mp_signed_bin_size(&(a->terms[x]));
  32       dst[y++] = z&255;
  33       dst[y++] = (z>>8)&255;
  34       if ((err = mp_to_signed_bin(&(a->terms[x]), dst+y)) != MP_OKAY)             { return err; }
  35       y += z;
  36    }
  37
  38    return MP_OKAY;
  39 }
  40
  41
  42