Documentation
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Overview ¶
Package gzip implements reading and writing of gzip format compressed files, as specified in RFC 1952.
Index ¶
Constants ¶
This section is empty.
Variables ¶
var ( // ErrChecksum is returned when reading GZIP data that has an invalid checksum. ErrChecksum = errors.New("gzip: invalid checksum") // ErrHeader is returned when reading GZIP data that has an invalid header. ErrHeader = errors.New("gzip: invalid header") )
Functions ¶
This section is empty.
Types ¶
type Header ¶
type Header struct {
Comment string // comment
Extra []byte // "extra data"
ModTime time.Time // modification time
Name string // file name
OS byte // operating system type
}
The gzip file stores a header giving metadata about the compressed file. That header is exposed as the fields of the Writer and Reader structs.
Strings must be UTF-8 encoded and may only contain Unicode code points U+0001 through U+00FF, due to limitations of the GZIP file format.
type Reader ¶
type Reader struct {
Header // valid after NewReader or Reader.Reset
Trailer *Trailer // valid after hitting EOF
// contains filtered or unexported fields
}
A Reader 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 Reader return the concatenation of the uncompressed data of each. Only the first header is recorded in the Reader fields.
Gzip files store a length and checksum of the uncompressed data. The Reader will return an ErrChecksum 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 io.EOF marking the end of the data.
func Continue ¶
func Continue(r io.Reader, span int64, from *flate.Checkpoint, updates chan<- *flate.Checkpoint) (*Reader, error)
func NewReader ¶
NewReader creates a new Reader reading the given reader. If r does not also implement io.ByteReader, the decompressor may read more data than necessary from r.
It is the caller's responsibility to call Close on the Reader when done.
The Reader.Header fields will be valid in the Reader returned.
func NewReaderWithSpans ¶
func (*Reader) Close ¶
Close closes the Reader. It does not close the underlying io.Reader. In order for the GZIP checksum to be verified, the reader must be fully consumed until the io.EOF.
func (*Reader) CompressedCount ¶
func (*Reader) Multistream ¶
Multistream controls whether the reader supports multistream files.
If enabled (the default), the Reader expects the input to be a sequence of individually gzipped data streams, each with its own header and trailer, ending at EOF. The effect is that the concatenation of a sequence of gzipped files is treated as equivalent to the gzip of the concatenation of the sequence. This is standard behavior for gzip readers.
Calling Multistream(false) disables this behavior; disabling the behavior can be useful when reading file formats that distinguish individual gzip data streams or mix gzip data streams with other data streams. In this mode, when the Reader reaches the end of the data stream, Read returns io.EOF. The underlying reader must implement io.ByteReader in order to be left positioned just after the gzip stream. To start the next stream, call z.Reset(r) followed by z.Multistream(false). If there is no next stream, z.Reset(r) will return io.EOF.
func (*Reader) Read ¶
Read implements io.Reader, reading uncompressed bytes from its underlying Reader.
func (*Reader) Reset ¶
Reset discards the Reader z's state and makes it equivalent to the result of its original state from NewReader, but reading from r instead. This permits reusing a Reader rather than allocating a new one.
Source Files