package zlib
import "compress/zlib"
Package zlib implements reading and writing of zlib format compressed data, as specified in RFC 1950.
The implementation provides filters that uncompress during reading and compress during writing. For example, to write compressed data to a buffer:
var b bytes.Buffer w := zlib.NewWriter(&b) w.Write([]byte("hello, world\n")) w.Close()
and to read that data back:
r, err := zlib.NewReader(&b) io.Copy(os.Stdout, r) r.Close()
Index ¶
- Constants
- Variables
- func NewReader(r io.Reader) (io.ReadCloser, error)
- func NewReaderDict(r io.Reader, dict []byte) (io.ReadCloser, error)
- type Writer
- func NewWriter(w io.Writer) *Writer
- func NewWriterLevel(w io.Writer, level int) (*Writer, error)
- func NewWriterLevelDict(w io.Writer, level int, dict []byte) (*Writer, error)
- func (z *Writer) Close() error
- func (z *Writer) Flush() error
- func (z *Writer) Reset(w io.Writer)
- func (z *Writer) Write(p []byte) (n int, err error)
Examples ¶
Constants ¶
const ( NoCompression = flate.NoCompression BestSpeed = flate.BestSpeed BestCompression = flate.BestCompression DefaultCompression = flate.DefaultCompression )
These constants are copied from the flate package, so that code that imports "compress/zlib" does not also have to import "compress/flate".
Variables ¶
var ( // ErrChecksum is returned when reading ZLIB data that has an invalid checksum. ErrChecksum = errors.New("zlib: invalid checksum") // ErrDictionary is returned when reading ZLIB data that has an invalid dictionary. ErrDictionary = errors.New("zlib: invalid dictionary") // ErrHeader is returned when reading ZLIB data that has an invalid header. ErrHeader = errors.New("zlib: invalid header") )
Functions ¶
func NewReader ¶
func NewReader(r io.Reader) (io.ReadCloser, error)
NewReader creates a new io.ReadCloser.
Reads from the returned io.ReadCloser read and decompress data from r.
The implementation buffers input and may read more data than necessary from r.
It is the caller's responsibility to call Close on the ReadCloser when done.
Code:play
Output:Example¶
package main
import (
"bytes"
"compress/zlib"
"io"
"os"
)
func main() {
buff := []byte{120, 156, 202, 72, 205, 201, 201, 215, 81, 40, 207,
47, 202, 73, 225, 2, 4, 0, 0, 255, 255, 33, 231, 4, 147}
b := bytes.NewReader(buff)
r, err := zlib.NewReader(b)
if err != nil {
panic(err)
}
io.Copy(os.Stdout, r)
r.Close()
}
hello, world
func NewReaderDict ¶
NewReaderDict is like NewReader but uses a preset dictionary. NewReaderDict ignores the dictionary if the compressed data does not refer to it.
Types ¶
type Writer ¶
type Writer struct {
// contains filtered or unexported fields
}
A Writer takes data written to it and writes the compressed form of that data to an underlying writer (see NewWriter).
func NewWriter ¶
NewWriter creates a new Writer. Writes to the returned Writer are compressed and written to w.
It is the caller's responsibility to call Close on the WriteCloser when done. Writes may be buffered and not flushed until Close.
func NewWriterLevel ¶
NewWriterLevel is like NewWriter but specifies the compression level instead of assuming DefaultCompression.
The compression level can be DefaultCompression, NoCompression, or any integer value between BestSpeed and BestCompression inclusive. The error returned will be nil if the level is valid.
func NewWriterLevelDict ¶
NewWriterLevelDict is like NewWriterLevel but specifies a dictionary to compress with.
The dictionary may be nil. If not, its contents should not be modified until the Writer is closed.
func (*Writer) Close ¶
Calling Close does not close the wrapped io.Writer originally passed to NewWriter.
func (*Writer) Flush ¶
Flush flushes the Writer to its underlying io.Writer.
func (*Writer) Reset ¶
Reset clears the state of the Writer z such that it is equivalent to its initial state from NewWriterLevel or NewWriterLevelDict, but instead writing to w.
func (*Writer) Write ¶
Write writes a compressed form of p to the underlying io.Writer. The compressed bytes are not necessarily flushed until the Writer is closed or explicitly flushed.
Source Files ¶
- Version
- v1.3.0-rc.2
- Published
- Jun 13, 2014
- Platform
- windows/amd64
- Imports
- 7 packages
- Last checked
- 2 seconds ago –
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