/*
* (C) 2015 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/

#include "tests.h"

#if defined(BOTAN_HAS_MCELIECE)
   #include <botan/internal/gf2m_small_m.h>
#endif

namespace Botan_Tests {

namespace {

#if defined(BOTAN_HAS_MCELIECE)

class GF2m_Tests final : public Test {
   public:
      std::vector<Test::Result> run() override {
         std::vector<Test::Result> results;

         results.push_back(test_gf_overflow());

         return results;
      }

   private:
      static Test::Result test_gf_overflow() {
         Test::Result result("GF2m");

         /*
         * This is testing one specific case where an overflow
         * occurred. It should be extended to test more of the interface.
         */
         for(size_t degree = 2; degree <= 15; ++degree) {
            Botan::GF2m_Field field(degree);

            for(size_t i = 0; i <= field.gf_ord(); ++i) {
               Botan::gf2m a = static_cast<Botan::gf2m>(i);

               result.test_eq("square vs multiply",
                              static_cast<size_t>(field.gf_square(a)),
                              static_cast<size_t>(field.gf_mul(a, a)));

               /*
               * This sequence is from the start of gf2m_decomp_rootfind_state::calc_Fxj_j_neq_0
               */
               {
                  const Botan::gf2m jl_gray = field.gf_l_from_n(a);
                  const Botan::gf2m xl_j_tt_5 = field.gf_square_rr(jl_gray);
                  const Botan::gf2m xl_gray_tt_3 = field.gf_mul_rrr(xl_j_tt_5, jl_gray);
                  Botan::gf2m s = field.gf_mul_nrr(xl_gray_tt_3, field.gf_ord());

                  result.test_gte("Value less than order", field.gf_ord(), s);
               }
            }
         }
         return result;
      }
};

BOTAN_REGISTER_TEST("pubkey", "gf2m", GF2m_Tests);

#endif

}  // namespace

}  // namespace Botan_Tests
