Function Xunzip

src/textfile_gui.cpp:819–844

* Do an in-memory xunzip operation. This works on a .xz or (legacy) * .lzma file. * @param input Buffer containing the input data. * @return Decompressed buffer. * * When decompressing fails, an empty buffer is returned. */

 * When decompressing fails, an empty buffer is returned.
 */
static std::vector<char> Xunzip(std::span<char> input)
{
	static const int BLOCKSIZE = 8192;
	std::vector<char> output;

	lzma_stream z = LZMA_STREAM_INIT;
	z.next_in = reinterpret_cast<uint8_t *>(input.data());
	z.avail_in = input.size();

	int res = lzma_auto_decoder(&z, UINT64_MAX, LZMA_CONCATENATED);
	/* Z_BUF_ERROR just means we need more space */
	while (res == LZMA_OK || (res == LZMA_BUF_ERROR && z.avail_out == 0)) {
		/* When we get here, we're either just starting, or
		 * inflate is out of output space - allocate more */
		z.avail_out += BLOCKSIZE;
		output.resize(output.size() + BLOCKSIZE);
		z.next_out = reinterpret_cast<uint8_t *>(output.data() + output.size() - z.avail_out);
		res = lzma_code(&z, LZMA_FINISH);
	}

	lzma_end(&z);
	if (res != LZMA_STREAM_END) return {};

	output.resize(output.size() - z.avail_out);
	return output;
}
#endif