text: /*
  Regression Test for the short BCH codes encoder and decoder
  
  Copyright 2020 Ahmet Inan <inan@aicodix.de>
  */
  
  #include <cassert>
  #include <random>
  #include <iostream>
  #include <functional>
  #include "short_bch_code_decoder.hh"
  #include "short_bch_code_encoder.hh"
  
  template <int N, int K, int T, int POLY>
  void bch_test(int trials)
  {
  	CODE::ShortBCHCodeEncoder<N, K, POLY> encode;
  	CODE::ShortBCHCodeDecoder<N, K, POLY, T> decode;
  	std::random_device rd;
  	typedef std::default_random_engine generator;
  	typedef std::uniform_int_distribution<int> distribution;
  	auto data = std::bind(distribution(0, (1<<K)-1), generator(rd()));
  	auto epos = std::bind(distribution(0, N-1), generator(rd()));
  	while (--trials) {
  		int message = data();
  		int codeword = encode(message);
  		assert((codeword>>(N-K)) == message);
  		int decoded = decode(codeword);
  		assert(decoded == codeword);
  		int damaged = codeword;
  		for (int i = 0; i < T; ++i)
  			damaged ^= 1 << epos();
  		int recovered = decode(damaged);
  		assert(recovered == codeword);
  	}
  }
  
  int main()
  {
  	if (1) {
  		// Perfect binary Golay code using x^11+x^9+x^7+x^6+x^5+x+1
  		bch_test<23, 12, 3, 0b101011100011>(1000000);
  	}
  	if (1) {
  		// Perfect binary Golay code using x^11+x^10+x^6+x^5+x^4+x^2+1
  		bch_test<23, 12, 3, 0b110001110101>(1000000);
  	}
  	if (1) {
  		// NASA INTRO BCH(15, 5) T=3
  		bch_test<15, 5, 3, 0b10100110111>(1000000);
  	}
  	if (1) {
  		// BCH(31, 16) T=3
  		bch_test<31, 16, 3, 0b1000111110101111>(1000000);
  	}
  	std::cerr << "Short BCH code regression test passed!" << std::endl;
  	return 0;
  }
  
  