Package gzip
import "compress/gzip"
The gzip package implements reading and writing of gzip format compressed files, as specified in RFC 1952.
Package files
gunzip.go gzip.goConstants
These constants are copied from the flate package, so that code that imports "compress/gzip" does not also have to import "compress/flate".
const (
NoCompression = flate.NoCompression
BestSpeed = flate.BestSpeed
BestCompression = flate.BestCompression
DefaultCompression = flate.DefaultCompression
)
Variables
var ChecksumError os.Error = os.ErrorString("gzip checksum error")
var HeaderError os.Error = os.ErrorString("invalid gzip header")
type Deflater
A Deflater is an io.WriteCloser that satisfies writes by compressing data written to its wrapped io.Writer.
type Deflater struct {
Header
// contains unexported fields
}
func NewDeflater
func NewDeflater(w io.Writer) (*Deflater, os.Error)
NewDeflater calls NewDeflaterLevel with the default compression level.
func NewDeflaterLevel
func NewDeflaterLevel(w io.Writer, level int) (*Deflater, os.Error)
NewDeflaterLevel creates a new Deflater writing to the given writer. Writes may be buffered and not flushed until Close. Callers that wish to set the fields in Deflater.Header must do so before the first call to Write or Close. It is the caller's responsibility to call Close on the WriteCloser when done. level is the compression level, which can be DefaultCompression, NoCompression, or any integer value between BestSpeed and BestCompression (inclusive).
func (*Deflater) Close
func (z *Deflater) Close() os.Error
Calling Close does not close the wrapped io.Writer originally passed to NewDeflater.
func (*Deflater) Write
func (z *Deflater) Write(p []byte) (int, os.Error)
type Header
The gzip file stores a header giving metadata about the compressed file. That header is exposed as the fields of the Deflater and Inflater structs.
type Header struct {
Comment string // comment
Extra []byte // "extra data"
Mtime uint32 // modification time (seconds since January 1, 1970)
Name string // file name
OS byte // operating system type
}
type Inflater
An Inflater is an io.Reader that can be read to retrieve uncompressed data from a gzip-format compressed file.
In general, a gzip file can be a concatenation of gzip files, each with its own header. Reads from the Inflater return the concatenation of the uncompressed data of each. Only the first header is recorded in the Inflater fields.
Gzip files store a length and checksum of the uncompressed data. The Inflater will return a ChecksumError when Read reaches the end of the uncompressed data if it does not have the expected length or checksum. Clients should treat data returned by Read as tentative until they receive the successful (zero length, nil error) Read marking the end of the data.
type Inflater struct {
Header
// contains unexported fields
}
func NewInflater
func NewInflater(r io.Reader) (*Inflater, os.Error)
NewInflater creates a new Inflater reading the given reader. The implementation buffers input and may read more data than necessary from r. It is the caller's responsibility to call Close on the Inflater when done.
func (*Inflater) Close
func (z *Inflater) Close() os.Error
Calling Close does not close the wrapped io.Reader originally passed to NewInflater.
func (*Inflater) Read
func (z *Inflater) Read(p []byte) (n int, err os.Error)
Bugs
Comments and Names don't properly map UTF-8 character codes outside of the 0x00-0x7f range to ISO 8859-1 (Latin-1).