Class Poco::DeflatingStreamBuf

File Information

Library: Foundation
Package: Streams
Header: Poco/DeflatingStream.h

Description

This is the streambuf class used by DeflatingInputStream and DeflatingOutputStream. The actual work is delegated to zlib (see http://zlib.net). Both zlib (deflate) streams and gzip streams are supported. Output streams should always call close() to ensure proper completion of compression. A compression level (0 to 9) can be specified in the constructor.

Inheritance

Direct Base Classes: BufferedStreamBuf

All Base Classes: BufferedStreamBuf

Member Summary

Member Functions: close, readFromDevice, sync, writeToDevice

Enumerations

StreamType

STREAM_ZLIB

Create a zlib header, use Adler-32 checksum.

STREAM_GZIP

Create a gzip header, use CRC-32 checksum.

Constructors

DeflatingStreamBuf

DeflatingStreamBuf(
    std::istream & istr,
    StreamType type,
    int level
);

Creates a DeflatingStreamBuf for compressing data read from the given input stream.

DeflatingStreamBuf

DeflatingStreamBuf(
    std::istream & istr,
    int windowBits,
    int level
);

Creates a DeflatingStreamBuf for compressing data read from the given input stream.

Please refer to the zlib documentation of deflateInit2() for a description of the windowBits parameter.

DeflatingStreamBuf

DeflatingStreamBuf(
    std::ostream & ostr,
    StreamType type,
    int level
);

Creates a DeflatingStreamBuf for compressing data passed through and forwarding it to the given output stream.

DeflatingStreamBuf

DeflatingStreamBuf(
    std::ostream & ostr,
    int windowBits,
    int level
);

Creates a DeflatingStreamBuf for compressing data passed through and forwarding it to the given output stream.

Please refer to the zlib documentation of deflateInit2() for a description of the windowBits parameter.

Destructor

~DeflatingStreamBuf

~DeflatingStreamBuf();

Destroys the DeflatingStreamBuf.

Member Functions

close

int close();

Finishes up the stream.

Must be called when deflating to an output stream.