zlib网站上有一个用法示例:http://www.zlib.net/zlib_how.html
然而,在这个例子中,他们正在压缩一个文件。我想压缩存储在内存缓冲区中的二进制数据。我也不想把压缩的缓冲区保存到磁盘上。
基本上,这是我的缓冲区:
fIplImageHeader->imageData = (char*)imageIn->getFrame();
我怎么用zlib压缩呢?
我会感谢一些如何做到这一点的代码示例。
发布于 2010-12-27 20:55:38
这是一个使用zlib打包缓冲区并将压缩后的内容保存到向量中的示例。
void compress_memory(void *in_data, size_t in_data_size, std::vector<uint8_t> &out_data)
{
std::vector<uint8_t> buffer;
const size_t BUFSIZE = 128 * 1024;
uint8_t temp_buffer[BUFSIZE];
z_stream strm;
strm.zalloc = 0;
strm.zfree = 0;
strm.next_in = reinterpret_cast<uint8_t *>(in_data);
strm.avail_in = in_data_size;
strm.next_out = temp_buffer;
strm.avail_out = BUFSIZE;
deflateInit(&strm, Z_BEST_COMPRESSION);
while (strm.avail_in != 0)
{
int res = deflate(&strm, Z_NO_FLUSH);
assert(res == Z_OK);
if (strm.avail_out == 0)
{
buffer.insert(buffer.end(), temp_buffer, temp_buffer + BUFSIZE);
strm.next_out = temp_buffer;
strm.avail_out = BUFSIZE;
}
}
int deflate_res = Z_OK;
while (deflate_res == Z_OK)
{
if (strm.avail_out == 0)
{
buffer.insert(buffer.end(), temp_buffer, temp_buffer + BUFSIZE);
strm.next_out = temp_buffer;
strm.avail_out = BUFSIZE;
}
deflate_res = deflate(&strm, Z_FINISH);
}
assert(deflate_res == Z_STREAM_END);
buffer.insert(buffer.end(), temp_buffer, temp_buffer + BUFSIZE - strm.avail_out);
deflateEnd(&strm);
out_data.swap(buffer);
}
发布于 2012-04-08 22:26:44
zlib.h
拥有您需要的所有函数:compress
(或compress2
)和uncompress
。请参阅zlib的源代码以获得答案。
ZEXTERN int ZEXPORT compress OF((Bytef *dest, uLongf *destLen, const Bytef *source, uLong sourceLen));
/*
Compresses the source buffer into the destination buffer. sourceLen is
the byte length of the source buffer. Upon entry, destLen is the total size
of the destination buffer, which must be at least the value returned by
compressBound(sourceLen). Upon exit, destLen is the actual size of the
compressed buffer.
compress returns Z_OK if success, Z_MEM_ERROR if there was not
enough memory, Z_BUF_ERROR if there was not enough room in the output
buffer.
*/
ZEXTERN int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen, const Bytef *source, uLong sourceLen));
/*
Decompresses the source buffer into the destination buffer. sourceLen is
the byte length of the source buffer. Upon entry, destLen is the total size
of the destination buffer, which must be large enough to hold the entire
uncompressed data. (The size of the uncompressed data must have been saved
previously by the compressor and transmitted to the decompressor by some
mechanism outside the scope of this compression library.) Upon exit, destLen
is the actual size of the uncompressed buffer.
uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
enough memory, Z_BUF_ERROR if there was not enough room in the output
buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete. In
the case where there is not enough room, uncompress() will fill the output
buffer with the uncompressed data up to that point.
*/
https://stackoverflow.com/questions/4538586
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