void PNG_file::decode(const char *outputFileName) {
    //BEGIN DECODING HERE

    FILE * outputFile;

    unsigned char buffer = 0;

    outputFile = fopen (outputFileName,"wb");

    //Check if the file opened
    if(!outputFile)
        exit(1);

    unsigned int size = 0;

    //
    for(int y=0; y < read_ptr->height; y++) {
        int x=0;
        //Write the file size into the file y==0 ensures that it only happens
        //once
        if(y == 0)
            for(x; x < SIZE_WIDTH; x++) {
                size |= ((*(row_pointers[0]+x) & 1 ) << x);
            }
        for(x; x < read_ptr->width*3; x++) {
            if((x > SIZE_WIDTH || y > 0) && x%BYTE_SIZE == 0) {
                fwrite(&buffer, 1, 1, outputFile);
                buffer = 0;
            }
            //png_bytep here = row_pointers[y]+x; for debugging
            if(((read_ptr->width*y)*3+x) == size*BYTE_SIZE+SIZE_WIDTH)
                goto loop_end;
            buffer |= ((*(row_pointers[y]+x) & 1) << x%BYTE_SIZE);
        }
    }

    //goto jumps here to break out of multiple loops
    loop_end:

    fclose(outputFile);
}