void ZipWriter::begin_file(const std::string &filename, bool compress)
{
if (impl->file_begun)
throw Exception("ZipWriter already writing a file");
impl->file_begun = true;
impl->uncompressed_length = 0;
impl->compressed_length = 0;
impl->compress = compress;
impl->crc32 = ZIP_CRC_START_VALUE;
impl->local_header_offset = impl->output.get_position();
impl->local_header = ZipLocalFileHeader();
impl->local_header.version_needed_to_extract = 20;
if (impl->storeFilenamesAsUTF8)
impl->local_header.general_purpose_bit_flag = ZIP_USE_UTF8;
else
impl->local_header.general_purpose_bit_flag = 0;
impl->local_header.compression_method = compress ? zip_compress_deflate : zip_compress_store;
ZipArchive_Impl::calc_time_and_date(
impl->local_header.last_mod_file_date,
impl->local_header.last_mod_file_time);
impl->local_header.crc32 = 0;
impl->local_header.uncompressed_size = 0;
impl->local_header.compressed_size = 0;
impl->local_header.file_name_length = filename.length();
impl->local_header.filename = filename;
if (!impl->storeFilenamesAsUTF8) // Add UTF-8 as extra field if we aren't storing normal UTF-8 filenames
{
// -Info-ZIP Unicode Path Extra Field (0x7075)
std::string filename_cp437 = StringHelp::text_to_cp437(filename);
std::string filename_utf8 = StringHelp::text_to_utf8(filename);
DataBuffer unicode_path(9 + filename_utf8.length());
uint16_t *extra_id = (uint16_t *)(unicode_path.get_data());
uint16_t *extra_len = (uint16_t *)(unicode_path.get_data() + 2);
uint8_t *extra_version = (uint8_t *)(unicode_path.get_data() + 4);
uint32_t *extra_crc32 = (uint32_t *)(unicode_path.get_data() + 5);
*extra_id = 0x7075;
*extra_len = 5 + filename_utf8.length();
*extra_version = 1;
*extra_crc32 = ZipArchive_Impl::calc_crc32(filename_cp437.data(), filename_cp437.size());
memcpy(unicode_path.get_data() + 9, filename_utf8.data(), filename_utf8.length());
impl->local_header.extra_field_length = unicode_path.get_size();
impl->local_header.extra_field = unicode_path;
}
impl->local_header.save(impl->output);
if (compress)
{
memset(&impl->zs, 0, sizeof(mz_stream));
int result = mz_deflateInit2(&impl->zs, MZ_DEFAULT_COMPRESSION, MZ_DEFLATED, -15, 8, MZ_DEFAULT_STRATEGY); // Undocumented: if wbits is negative, zlib skips header check
if (result != MZ_OK)
throw Exception("Zlib deflateInit failed for zip index!");
}
}
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();
}
