ZipStreamBuf::ZipStreamBuf(std::istream& istr, const ZipLocalFileHeader& fileEntry, bool reposition):
Poco::BufferedStreamBuf(STREAM_BUFFER_SIZE, std::ios::in),
_pIstr(&istr),
_pOstr(0),
_ptrBuf(),
_ptrOBuf(),
_ptrHelper(),
_ptrOHelper(),
_crc32(Poco::Checksum::TYPE_CRC32),
_expectedCrc32(0),
_checkCRC(true),
_bytesWritten(0),
_pHeader(0)
{
if (fileEntry.isDirectory())
return;
_expectedCrc32 = fileEntry.getCRC();
std::streamoff start = fileEntry.getDataStartPos();
std::streamoff end = fileEntry.getDataEndPos();
_checkCRC = !fileEntry.searchCRCAndSizesAfterData();
if (fileEntry.getCompressionMethod() == ZipCommon::CM_DEFLATE)
{
// Fake init bytes at beginning of stream
std::string init = ZipUtil::fakeZLibInitString(fileEntry.getCompressionLevel());
// Fake adler at end of stream: just some dummy value, not checked anway
std::string crc(4, ' ');
if (fileEntry.searchCRCAndSizesAfterData())
{
_ptrHelper = new AutoDetectInputStream(istr, init, crc, reposition, start);
}
else
{
_ptrHelper = new PartialInputStream(istr, start, end, reposition, init, crc);
}
_ptrBuf = new Poco::InflatingInputStream(*_ptrHelper, Poco::InflatingStreamBuf::STREAM_ZIP);
}
else if (fileEntry.getCompressionMethod() == ZipCommon::CM_STORE)
{
if (fileEntry.searchCRCAndSizesAfterData())
{
_ptrBuf = new AutoDetectInputStream(istr, "", "", reposition, start);
}
else
{
_ptrBuf = new PartialInputStream(istr, start, end, reposition);
}
}
else throw Poco::NotImplementedException("Unsupported compression method");
}
