예제 #1
0
func ExampleWriter_RegisterCompressor() {
	// Override the default Deflate compressor with a higher compression
	// level.

	// Create a buffer to write our archive to.
	buf := new(bytes.Buffer)

	// Create a new zip archive.
	w := zip.NewWriter(buf)

	var fw *flate.Writer

	// Register the deflator.
	w.RegisterCompressor(zip.Deflate, func(out io.Writer) (io.WriteCloser, error) {
		var err error
		if fw == nil {
			// Creating a flate compressor for every file is
			// expensive, create one and reuse it.
			fw, err = flate.NewWriter(out, flate.BestCompression)
		} else {
			fw.Reset(out)
		}
		return fw, err
	})

	// Proceed to add files to w.
}
예제 #2
0
파일: gzip.go 프로젝트: glycerine/pgzip
// Step 1: compresses buffer to buffer
// Step 2: send writer to channel
// Step 3: Close result channel to indicate we are done
func compressBlock(p, prevTail []byte, z Writer, r result) {
	defer close(r.result)
	buf := make([]byte, 0, len(p))
	dest := bytes.NewBuffer(buf)

	var compressor *flate.Writer
	var err error
	if len(prevTail) > 0 {
		compressor, err = flate.NewWriterDict(dest, z.level, prevTail)
	} else {
		compressor, err = flate.NewWriter(dest, z.level)
	}
	if err != nil {
		z.pushError(err)
		return
	}
	compressor.Write(p)

	err = compressor.Flush()
	if err != nil {
		z.pushError(err)
		return
	}
	if z.closed {
		err = compressor.Close()
		if err != nil {
			z.pushError(err)
			return
		}
	}
	// Read back buffer
	buf = dest.Bytes()
	r.result <- buf
}