/*

* (C) 2021 Jack Lloyd

*

* Botan is released under the Simplified BSD License (see license.txt)

*/

#include "fuzzers.h"

#include <botan/numthry.h>

namespace {

Botan::BigInt ref_gcd(Botan::BigInt a,

                      Botan::BigInt b)

   {

   Botan::BigInt t;

   while(b != 0)

      {

      t = a % b;

      t.swap(b);

      t.swap(a);

      }

   return a;

   }

}

void fuzz(const uint8_t in[], size_t len)

   {

   static const size_t max_bits = 4096;

   if(2*len*8 > max_bits)

      return;

   const Botan::BigInt x = Botan::BigInt::decode(in, len / 2);

   const Botan::BigInt y = Botan::BigInt::decode(in + len / 2, len - (len / 2));

   const Botan::BigInt ref = ref_gcd(x, y);

   const Botan::BigInt lib = Botan::gcd(x, y);

   if(ref != lib)

      {

      FUZZER_WRITE_AND_CRASH("X = " << x << "\n"

                             << "Y = " << y << "\n"

                             << "L = " << lib << "\n"

                             << "R = " << ref << "\n");

      }

   }