DataBuffer ZLibCompression::compress(const DataBuffer &data, bool raw, int compression_level, CompressionMode mode)
{
const int window_bits = 15;
DataBuffer zbuffer(1024*1024);
IODevice_Memory output;
int strategy = MZ_DEFAULT_STRATEGY;
switch (mode)
{
case default_strategy: strategy = MZ_DEFAULT_STRATEGY; break;
case filtered: strategy = MZ_FILTERED; break;
case huffman_only: strategy = MZ_HUFFMAN_ONLY; break;
case rle: strategy = MZ_RLE; break;
case fixed: strategy = MZ_FIXED; break;
}
mz_stream zs = { nullptr };
int result = mz_deflateInit2(&zs, compression_level, MZ_DEFLATED, raw ? -window_bits : window_bits, 8, strategy); // Undocumented: if wbits is negative, zlib skips header check
if (result != MZ_OK)
throw Exception("Zlib deflateInit failed");
try
{
zs.next_in = (unsigned char *) data.get_data();
zs.avail_in = data.get_size();
while (true)
{
zs.next_out = (unsigned char *) zbuffer.get_data();
zs.avail_out = zbuffer.get_size();
int result = mz_deflate(&zs, MZ_FINISH);
if (result == MZ_NEED_DICT) throw Exception("Zlib deflate wants a dictionary!");
if (result == MZ_DATA_ERROR) throw Exception("Zip data stream is corrupted");
if (result == MZ_STREAM_ERROR) throw Exception("Zip stream structure was inconsistent!");
if (result == MZ_MEM_ERROR) throw Exception("Zlib did not have enough memory to compress file!");
if (result == MZ_BUF_ERROR) throw Exception("Not enough data in buffer when Z_FINISH was used");
if (result != MZ_OK && result != MZ_STREAM_END) throw Exception("Zlib deflate failed while compressing zip file!");
int zsize = zbuffer.get_size() - zs.avail_out;
if (zsize == 0)
break;
output.write(zbuffer.get_data(), zsize);
if (result == MZ_STREAM_END)
break;
}
mz_deflateEnd(&zs);
}
catch (...)
{
mz_deflateEnd(&zs);
throw;
}
return output.get_data();
}
~ZipWriter_Impl()
{
if (file_begun && compress)
{
mz_deflateEnd(&zs);
}
}
void ZipWriter::end_file()
{
if (!impl->file_begun)
return;
if (impl->compress)
{
impl->zs.next_in = nullptr;
impl->zs.avail_in = 0;
while (true)
{
impl->zs.next_out = (unsigned char *)impl->zbuffer;
impl->zs.avail_out = 16 * 1024;
int result = mz_deflate(&impl->zs, MZ_FINISH);
if (result == MZ_NEED_DICT) throw Exception("Zlib deflate wants a dictionary!");
if (result == MZ_DATA_ERROR) throw Exception("Zip data stream is corrupted");
if (result == MZ_STREAM_ERROR) throw Exception("Zip stream structure was inconsistent!");
if (result == MZ_MEM_ERROR) throw Exception("Zlib did not have enough memory to compress file!");
if (result == MZ_BUF_ERROR) throw Exception("Not enough data in buffer when Z_FINISH was used");
if (result != MZ_OK && result != MZ_STREAM_END) throw Exception("Zlib deflate failed while compressing zip file!");
int64_t zsize = 16 * 1024 - impl->zs.avail_out;
if (zsize == 0)
break;
impl->output.write(impl->zbuffer, zsize);
impl->compressed_length += zsize;
if (result == MZ_STREAM_END)
break;
}
mz_deflateEnd(&impl->zs);
impl->compress = false;
}
impl->local_header.uncompressed_size = impl->uncompressed_length;
impl->local_header.compressed_size = impl->compressed_length;
impl->local_header.crc32 = ZipArchive_Impl::calc_crc32(nullptr, 0, impl->crc32, true);
int64_t current_offset = impl->output.get_position();
impl->output.seek(impl->local_header_offset);
impl->local_header.save(impl->output);
impl->output.seek(current_offset);
ZipWriter_Impl::FileEntry file_entry;
file_entry.local_header = impl->local_header;
file_entry.local_header_offset = impl->local_header_offset;
impl->written_files.push_back(file_entry);
impl->file_begun = false;
}
static int lmz_deflator_gc(lua_State* L) {
lmz_stream_t* stream = luaL_checkudata(L, 1, "miniz_deflator");
mz_deflateEnd(&(stream->stream));
return 0;
}
