videochargen/frame.cpp

/*  frame.cpp
 *  Takes a black/white (1bpp) PNM ASCII-armored image as input,
 *  and produces the frame.S assembly code to draw it
 *  as an analog video signal for this project's kernel.
 * */
#include <iostream>
#include <fstream>
#include <sstream>
#include <cstring>

enum ExitStatus {
    BAD_ARGUMENT = 1,
    FILE_NOT_OPEN = 2,
    FILE_BAD_FORMAT = 3
};

int main(int argc, char** argv) {
    if (argc < 2) {
        return BAD_ARGUMENT;
    }
    const int images = argc - 1;
    std::stringstream jump_table;
    std::stringstream asm_code;

    std::fstream outfile;
    outfile.open("frame.S", std::ios::out);
    if (! outfile) {
        return FILE_NOT_OPEN;
    }

    jump_table << "#include \"macro.h\"" << std::endl;
    jump_table << "#include <avr/io.h>" << std::endl;

    char** image = new char*[images];

    for (int current_image = 0; current_image < images; ++current_image) {
        std::fstream infile;

        infile.open(argv[1 + current_image], std::ios::in);
        if (! infile) {
            return FILE_NOT_OPEN;
        }

        int width, height;
        std::string format;
        char c;

        getline(infile, format);

        std::cout << format << std::endl;

        if (format != "P1") {
            return FILE_BAD_FORMAT;
        }

        // skip one line TODO
        getline(infile, format);
        std::cout << format << std::endl;

        infile >> width >> height;
        std::cout << width << " x " << height << std::endl;

        image[current_image] = new char[height * width];

        for (int y = 0; y < height; ) {
            for (int x = 0; x < width; ) {
                c = infile.get();
                if (! infile.good())
                    return FILE_BAD_FORMAT;
                if (c == '0' || c == '1') {
                    image[current_image][y * width + x] = c;
                    x++;
                } else {
                    continue;
                }
            }
            y++;
        }

        infile.close();

        jump_table << ".global line_jump_table_" << current_image << std::endl;
        jump_table << "line_jump_table_" << current_image << ":" << std::endl;

        for (int y = 0; y < height; ++y) {

            int diff = 1;

            for (int other_image = 0; other_image <= current_image; ++other_image) {
                for (int other_y = 0; other_y < height && other_y < y; ++other_y) {
                    diff = memcmp(&(image[current_image][y * width + 0]), &(image[other_image][other_y * width + 0]), width);
                    if (diff == 0) {
                        jump_table << '\t' << "jmp line_" << other_image << "_" << other_y << std::endl;
                        goto nested_loop_end;
                    }
                }
            }

nested_loop_end:

            if (diff == 0)
                continue;

            jump_table << '\t' << "jmp line_" << current_image << "_" << y << std::endl;
            asm_code << "line_" << current_image << "_" << y << ":" << std::endl;

            int count = 0;
            char last = image[current_image][y * width + 0];

            for (int x = 0; x < width; ++x) {
                char current = image[current_image][y * width + x];
                std::cout << "current " << current << " last " << last << std::endl;
                if (current == last) {
                    ++count;
                } else {
                    std::cout << "detected change" << std::endl;
                    if (last == '0') {
                        std::cout << "clear" << std::endl;
                        asm_code << '\t' << "cbi IO(PORTB), 4" << std::endl;
                    } else if (last == '1') {
                        std::cout << "set" << std::endl;
                        asm_code << '\t' << "sbi IO(PORTB), 4" << std::endl;
                    }

                    if (count > 1) {
                        asm_code << '\t' << "ldi r31, " << count - 1 << std::endl;
                        asm_code << "1:" << std::endl;
                        asm_code << '\t' << "dec r31" << std::endl;
                        asm_code << '\t' << "nop" << std::endl;
                        asm_code << '\t' << "brne 1b" << std::endl;
                    }

                    asm_code << '\t' << "rjmp 2f" << std::endl;
                    asm_code << "2:" << std::endl;

                    last = current;
                    count = 1;
                }
            }
            asm_code << '\t' << "cbi IO(PORTB), 4" << std::endl;
            asm_code << '\t' << "jmp jump_table_return_address" << std::endl;
        }

    }

    delete[] image;

    outfile << jump_table.str() << asm_code.str();

    outfile.close();
}