bsp; buffer[LZ77_BUFFER_SIZE],
*comp,
*temp,
next;
int offset,
length,
remaining,
hsize,
ipos,
opos,
tpos,
i;
/*使指向压缩数据的指针暂时无效*/
*compressed = NULL;
/*写入头部信息*/
hsize = sizeof(int);
if((comp = (unsigned char *)malloc(hsize)) == NULL)
return -1;
memcpy(comp,&size,sizeof(int));
/*初始化滑动窗口和前向缓冲区(用0填充)*/
memset(window, 0 , LZ77_WINDOW_SIZE);
memset(buffer, 0 , LZ77_BUFFER_SIZE);
/*加载前向缓冲区*/
ipos = 0;
for(i=0; i<LZ77_BUFFER_SIZE && ipos < size; i++)
{
buffer[i] = original[ipos];
ipos++;
}
/*压缩数据*/
opos = hsize * 8;
remaining = size;
while(remaining > 0)
{
if((length = compare_win(window,buffer,&offset,&next)) != 0)
{
/*编码短语标记*/
token = 0x00000001 << (LZ77_PHRASE_BITS - 1);
/*设置在滑动窗口找到匹配的偏移量*/
token = token | (offset << (LZ77_PHRASE_BITS - LZ77_TYPE_BITS - LZ77_WINOFF_BITS));
/*设置匹配串的长度*/
token = token | (length << (LZ77_PHRASE_BITS - LZ77_TYPE_BITS - LZ77_WINOFF_BITS - LZ77_BUFLEN_BITS));
/*设置前向缓冲区中匹配串后面紧邻的字符*/
token = token | next;
/*设置标记的位数*/
tbits = LZ77_PHRASE_BITS;
}
else
{
/*编码一个字符标记*/
token = 0x00000000;
/*设置未匹配的字符*/
token = token | next;
/*设置标记的位数*/
tbits = LZ77_SYMBOL_BITS;
}
/*确定标记是大端格式*/
token = htonl(token);
/*将标记写入压缩缓冲区*/
for(i=0; i<tbits; i++)
{
if(opos % 8 == 0)