Documentation
¶
Overview ¶
Package flate implements the DEFLATE compressed data format, described in RFC 1951. The gzip and zlib packages implement access to DEFLATE-based file formats.
Index ¶
- Constants
- func NewReader(r io.Reader) io.ReadCloser
- func NewReaderDict(r io.Reader, dict []byte) io.ReadCloser
- type Checkpoint
- type CorruptInputError
- type Decompressor
- func (f *Decompressor) Close() error
- func (f *Decompressor) Read(b []byte) (int, error)
- func (f *Decompressor) Reset(r io.Reader, dict []byte, roffset int64) error
- func (f *Decompressor) ResetTo(from *Checkpoint) (int64, error)
- func (f *Decompressor) ToRead() int64
- func (f *Decompressor) Woffset() int64
- type Header
- type InternalError
- type ReadErrordeprecated
- type Reader
- type Resetter
- type Trailer
- type Woffseter
- type WriteErrordeprecated
Constants ¶
const ( NoCompression = 0 BestSpeed = 1 BestCompression = 9 DefaultCompression = -1 // HuffmanOnly disables Lempel-Ziv match searching and only performs Huffman // entropy encoding. This mode is useful in compressing data that has // already been compressed with an LZ style algorithm (e.g. Snappy or LZ4) // that lacks an entropy encoder. Compression gains are achieved when // certain bytes in the input stream occur more frequently than others. // // Note that HuffmanOnly produces a compressed output that is // RFC 1951 compliant. That is, any valid DEFLATE decompressor will // continue to be able to decompress this output. HuffmanOnly = -2 )
Variables ¶
This section is empty.
Functions ¶
func NewReader ¶
func NewReader(r io.Reader) io.ReadCloser
NewReader returns a new ReadCloser that can be used to read the uncompressed version of r. If r does not also implement io.ByteReader, the decompressor may read more data than necessary from r. The reader returns io.EOF after the final block in the DEFLATE stream has been encountered. Any trailing data after the final block is ignored.
The ReadCloser returned by NewReader also implements Resetter.
func NewReaderDict ¶
func NewReaderDict(r io.Reader, dict []byte) io.ReadCloser
NewReaderDict is like NewReader but initializes the reader with a preset dictionary. The returned Reader behaves as if the uncompressed data stream started with the given dictionary, which has already been read. NewReaderDict is typically used to read data compressed by NewWriterDict.
The ReadCloser returned by NewReader also implements Resetter.
Types ¶
type Checkpoint ¶
type Checkpoint struct {
// TODO: separate these from the rest
In int64 `json:"in,omitempty"`
Out int64 `json:"out,omitempty"`
// bits?
B uint32 `json:"b,omitempty"`
NB uint `json:"nb,omitempty"`
Hist []byte `json:"hist,omitempty"`
// Trying random stuff...
WrPos int `json:"wrpos,omitempty"`
RdPos int `json:"rdpos,omitempty"`
Full bool `json:"full,omitempty"`
// If there is no Hist, we can avoid writing the file.
Empty bool `json:"empty,omitempty"`
// Optional gzip header.
GzipHeader *Header `json:"header,omitempty"`
}
func (*Checkpoint) BytesRead ¶
func (c *Checkpoint) BytesRead() int64
func (*Checkpoint) BytesWritten ¶
func (c *Checkpoint) BytesWritten() int64
func (*Checkpoint) History ¶
func (c *Checkpoint) History() []byte
func (*Checkpoint) IsEmpty ¶
func (c *Checkpoint) IsEmpty() bool
func (*Checkpoint) SetHistory ¶
func (c *Checkpoint) SetHistory(b []byte)
type CorruptInputError ¶
type CorruptInputError int64
A CorruptInputError reports the presence of corrupt input at a given offset.
func (CorruptInputError) Error ¶
func (e CorruptInputError) Error() string
type Decompressor ¶
type Decompressor struct {
// contains filtered or unexported fields
}
Decompress state.
func Continue ¶
func Continue(r io.Reader, from *Checkpoint, span int64, updates chan<- *Checkpoint) *Decompressor
func NewReaderWithSpans ¶
func NewReaderWithSpans(r io.Reader, span int64, start int64, updates chan<- *Checkpoint) *Decompressor
NewReaderWithSpans is a hack.
func (*Decompressor) Close ¶
func (f *Decompressor) Close() error
func (*Decompressor) ResetTo ¶
func (f *Decompressor) ResetTo(from *Checkpoint) (int64, error)
func (*Decompressor) ToRead ¶
func (f *Decompressor) ToRead() int64
func (*Decompressor) Woffset ¶
func (f *Decompressor) Woffset() int64
type InternalError ¶
type InternalError string
An InternalError reports an error in the flate code itself.
func (InternalError) Error ¶
func (e InternalError) Error() string
type ReadError
deprecated
type Reader ¶
type Reader interface {
io.Reader
io.ByteReader
}
The actual read interface needed by NewReader. If the passed in io.Reader does not also have ReadByte, the NewReader will introduce its own buffering.
type Resetter ¶
type Resetter interface {
// Reset discards any buffered data and resets the Resetter as if it was
// newly initialized with the given reader.
Reset(r io.Reader, dict []byte, roffset int64) error
}
Resetter resets a ReadCloser returned by NewReader or NewReaderDict to switch to a new underlying Reader. This permits reusing a ReadCloser instead of allocating a new one.
Source Files