static void rq_encode()

in sntrup4591761.c [626:660]

• 31 lines of code
• 2 McCabe index (conditional complexity)

static void rq_encode(unsigned char *c,const modq *f)
{
  crypto_int32 f0, f1, f2, f3, f4;
  int i;

  for (i = 0;i < p/5;++i) {
    f0 = *f++ + qshift;
    f1 = *f++ + qshift;
    f2 = *f++ + qshift;
    f3 = *f++ + qshift;
    f4 = *f++ + qshift;
    /* now want f0 + 6144*f1 + ... as a 64-bit integer */
    f1 *= 3;
    f2 *= 9;
    f3 *= 27;
    f4 *= 81;
    /* now want f0 + f1<<11 + f2<<22 + f3<<33 + f4<<44 */
    f0 += f1 << 11;
    *c++ = f0; f0 >>= 8;
    *c++ = f0; f0 >>= 8;
    f0 += f2 << 6;
    *c++ = f0; f0 >>= 8;
    *c++ = f0; f0 >>= 8;
    f0 += f3 << 1;
    *c++ = f0; f0 >>= 8;
    f0 += f4 << 4;
    *c++ = f0; f0 >>= 8;
    *c++ = f0; f0 >>= 8;
    *c++ = f0;
  }
  /* XXX: using p mod 5 = 1 */
  f0 = *f++ + qshift;
  *c++ = f0; f0 >>= 8;
  *c++ = f0;
}