void ZipIODevice_FileEntry::init()
{
iodevice.seek(file_entry.impl->record.relative_offset_of_local_header, IODevice::seek_set);
file_header.load(iodevice);
//This fix allows OS X created .zips to be opened - SAR
if (file_header.general_purpose_bit_flag & ZIP_CRC32_IN_FILE_DESCRIPTOR) //if this bit is set, it means the local header data for sizes was not
{
//the correct size data is not in the local header.. luckily, we have a real copy from the entry database
file_header.compressed_size = file_entry.get_compressed_size();
file_header.uncompressed_size = file_entry.get_uncompressed_size();
}
pos = 0;
compressed_pos = 0;
// Initialize decompression:
int result = 0;
switch (file_header.compression_method)
{
case zip_compress_store: // no compression
break;
case zip_compress_deflate:
memset(&zs, 0, sizeof(mz_stream));
zs.next_in = nullptr;
zs.avail_in = 0;
zs.zalloc = nullptr;
zs.zfree = nullptr;
zs.opaque = nullptr;
//result = inflateInit(&zs);
result = mz_inflateInit2(&zs, -15); // Undocumented: if wbits is negative, zlib skips header check
if (result != MZ_OK) throw Exception("Zlib inflateInit failed for zip index!");
zstream_open = true;
break;
case zip_compress_shrunk:
case zip_compress_expand_factor_1:
case zip_compress_expand_factor_2:
case zip_compress_expand_factor_3:
case zip_compress_expand_factor_4:
case zip_compress_implode:
case zip_compress_tokenize:
case zip_compress_deflate64:
case zip_compress_pkware_implode:
default:
throw Exception(string_format("Unsupported compression method %1", file_header.compression_method));
}
}
DataBuffer ZLibCompression::decompress(const DataBuffer &data, bool raw)
{
const int window_bits = 15;
DataBuffer zbuffer(1024*1024);
IODevice_Memory output;
mz_stream zs = { nullptr };
int result = mz_inflateInit2(&zs, raw ? -window_bits : window_bits);
if (result != MZ_OK)
throw Exception("Zlib inflateInit failed");
zs.next_in = (unsigned char *) data.get_data();
zs.avail_in = data.get_size();
// Continue feeding zlib data until we get our data:
while (true)
{
zs.next_out = (unsigned char *) zbuffer.get_data();
zs.avail_out = zbuffer.get_size();
// Decompress data:
int result = mz_inflate(&zs, 0);
if (result == MZ_NEED_DICT) throw Exception("Zlib inflate 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 decompress 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 inflate failed while decompressing zip file!");
output.write(zbuffer.get_data(), zbuffer.get_size() - zs.avail_out);
if (result == MZ_STREAM_END)
break;
}
mz_inflateEnd(&zs);
return output.get_data();
}
bool ZipReader::read_local_file_header(bool allow_data_descriptor)
{
try
{
impl->local_header.load(impl->input);
}
catch (const Exception&)
{
return false;
}
if (has_data_descriptor() && !allow_data_descriptor)
throw Exception("Zip file entry uses a data descriptor");
if ((impl->local_header.general_purpose_bit_flag & ZIP_ENCRYPTED) ||
(impl->local_header.general_purpose_bit_flag & ZIP_STRONG_ENCRYPTED))
throw Exception("Zip file entry is encrypted");
if (impl->zstream_open)
mz_inflateEnd(&impl->zs);
impl->zstream_open = false;
if (impl->local_header.compression_method == zip_compress_deflate)
{
memset(&impl->zs, 0, sizeof(mz_stream));
int result = mz_inflateInit2(&impl->zs, -15); // Undocumented: if wbits is negative, zlib skips header check
if (result != MZ_OK)
throw Exception("Zlib inflateInit failed for zip index!");
impl->zstream_open = true;
impl->compressed_pos = 0;
}
else if (impl->local_header.compression_method != zip_compress_store)
{
throw Exception("Zip file entry is compressed with an unsupported compression method");
}
return true;
}
