rle1.cpp

非常好用的五子棋游戏源码

// Created:09-24-98
// By Jeff Connelly

// RLE type 1 encoding/decoding

// Based on ORIGSRC\CODRLE1.C and ORIGSRC\DCODRLE1.C written by
// David Bourgin

// Similar algorithms are used in MacPackBit, Targa, PCX, TIFF and more

#include "stdafx.h"
#define EXPORTING
#include "comprlib.h"
#include "rle1.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

static void write_array(void* array, int bytes)
{
    register int i;
    for (i = 0; i < bytes; ++i)
        write_byte((char)((char*)array + i));
}

static void write_block(char byte, int time_nb)
{
    unsigned char array_to_write[129];
    memset(array_to_write, byte, time_nb);
    write_array(array_to_write, time_nb);
}

void EXPORT rle1_encode()
{
    register unsigned char byte1, byte2, frame_size, array[129];
    if (!end_of_data())
    {
        byte1 = read_byte();
        frame_size = 1;
        if (!end_of_data())
        {
            byte2 = read_byte();
            frame_size = 2;
            do
            {
                if (byte1 == byte2)
                {
                    while (!end_of_data() && (byte1 == byte2) &&
                           (frame_size < 129))
                    {
                        byte2 = read_byte();
                        ++frame_size;
                    }
                    if (byte1 == byte2)
                    {
                        write_byte(126 + frame_size);
                        write_byte(byte1);
                        if (!end_of_data())
                        {
                            byte1 = read_byte();
                            frame_size = 1;
                        }
                        else
                            frame_size = 0;
                    } else {
                        write_byte(125 + frame_size);
                        write_byte(byte1);
                        byte1 = byte2;
                        frame_size = 1;
                    }
                    if (!end_of_data())
                    {
                        byte2 = read_byte();
                        frame_size = 2;
                    }
                } else {
                    *array = byte1;
                    array[1] = byte2;
                    while (!end_of_data() && (array[frame_size - 2] !=
                            array[frame_size - 1]) && (frame_size < 128))
                    {
                        array[frame_size] = read_byte();
                        ++frame_size;
                    }
                    if (array[frame_size - 2] == array[frame_size - 1])
                    {
                        write_byte(frame_size - 3);
                        write_array(array, frame_size - 2);
                        byte1 = array[frame_size - 2];
                        byte2 = byte1;
                        frame_size = 2;
                    } else {
                        write_byte(frame_size - 1);
                        write_array(array, frame_size);
                        if (end_of_data())
                            frame_size = 0;
                        else
                        {
                            byte1 = read_byte();
                            if (end_of_data())
                                frame_size = 1;
                            else
                            {
                                byte2 = read_byte();
                                frame_size = 2;
                            }
                        }
                    }
                }
            } while ((!end_of_data()) || (frame_size >= 2));
        }
        if (frame_size == 1)
        {
            write_byte(0);
            write_byte(byte1);
        }
    }
}

void EXPORT rle1_decode ()
{
    unsigned char header;
    register unsigned char i;

    while (!end_of_data())
    {
        header = read_byte();
        switch(header & 128)
        {
            case 0: for (i = 0; i < header; i++)
                    write_byte(read_byte());
                    break;
            case 128: write_block(read_byte(), (header & 127 + 2));
        }
    }
    // Wow!  That code was short!
}