Function parse_netpbm_format_header

tests/AssetsLibrary.cpp:131–177

}

std::tuple<unsigned int, unsigned int, int> parse_netpbm_format_header(std::ifstream &fs, char number)
{
    // check file type magic number is valid
    std::array<char, 2> magic_number{{0}};
    fs >> magic_number[0] >> magic_number[1];

    if (magic_number[0] != 'P' || magic_number[1] != number)
    {
        throw std::runtime_error("File type magic number not supported");
    }

    discard_comments_and_spaces(fs);

    unsigned int width = 0;
    fs >> width;

    discard_comments_and_spaces(fs);

    unsigned int height = 0;
    fs >> height;

    discard_comments_and_spaces(fs);

    int max_value = 0;
    fs >> max_value;

    if (!fs.good())
    {
        throw std::runtime_error("Cannot read image dimensions");
    }

    if (max_value != 255)
    {
        throw std::runtime_error("RawTensor doesn't have 8-bit values");
    }

    discard_comments(fs);

    if (isspace(fs.peek()) == 0)
    {
        throw std::runtime_error("Invalid image header");
    }

    fs.ignore(1);

    return std::make_tuple(width, height, max_value);
}

std::tuple<unsigned int, unsigned int, int> parse_ppm_header(std::ifstream &fs)
{