// Handle command line arguments

if (argc != 3) {

std::cerr << "Usage: " << argv[0] << " InputFile OutputFile" << std::endl;

return EXIT_FAILURE;

}

const char *inputFile = argv[1];

const char *outputFile = argv[2];

// Read input file once to compute symbol frequencies

std::ifstream in(inputFile, std::ios::binary);

SimpleFrequencyTable freqs(std::vector<uint32_t>(257, 0));

freqs.increment(256); // EOF symbol gets a frequency of 1

while (true) {

int b = in.get();

if (b == std::char_traits<char>::eof())

break;

if (b < 0 || b > 255)

throw std::logic_error("Assertion error");

freqs.increment(static_cast<uint32_t>(b));

}

// Read input file again, compress with arithmetic coding, and write output file

in.clear();

in.seekg(0);

std::ofstream out(outputFile, std::ios::binary);

BitOutputStream bout(out);

try {

// Write frequency table

for (uint32_t i = 0; i < 256; i++) {

uint32_t freq = freqs.get(i);

for (int j = 31; j >= 0; j--)

bout.write(static_cast<int>((freq >> j) & 1)); // Big endian

}

ArithmeticEncoder enc(32, bout);

while (true) {

// Read and encode one byte

int symbol = in.get();

if (symbol == std::char_traits<char>::eof())

break;

if (!(0 <= symbol && symbol <= 255))

throw std::logic_error("Assertion error");

enc.write(freqs, static_cast<uint32_t>(symbol));

}

enc.write(freqs, 256); // EOF

enc.finish(); // Flush remaining code bits

bout.finish();

return EXIT_SUCCESS;

} catch (const char *msg) {

std::cerr << msg << std::endl;

return EXIT_FAILURE;

}