zlib解压压缩数据

LiteSetup中的压缩解压代码

zlib只是对内存段压缩解压，对于文件，咱们能够分段 读取到内存而后操做

注意compressBound 有BUG

若是存在压缩后的大小大于原大小，此函数返回的是压缩后最大大小 就会有错误，致使内存溢出

LiteSetup项目中发现这个BUG（如压缩一个已经rar压缩的文件，就可能溢出）

UnCompressBlock*	Core::UnCompressBuffer(char*buffer, unsigned int len, unsigned int len_orign)
{
	UnCompressBlock *ret = new UnCompressBlock;

	char *dest = new char[len_orign + 10];


	if (0 == uncompress((Bytef*)dest, (uLongf*)&len_orign, (Bytef*)buffer, len))
	{
		ret->buffer = dest;
		ret->_size = len_orign;

		return ret;
	}

	delete[] dest;
    delete ret;
	return nullptr;
}


CompressBlock* Core::CompressBuffer(char * buffer, unsigned int _size)
{
	CompressBlock *ret = new CompressBlock;

	unsigned int len = compressBound((uLong)_size);

	char * dest = new char[len+1024*1024];

	if (compress((Bytef*)dest, (uLongf*)&len, (Bytef*)buffer, _size) == 0)
	{
		ret->buffer = dest;
		ret->_size = len;
		ret->_size_orign = _size;

		return ret;
	}
    delete ret;
	delete[]dest;
	return nullptr;
}