README
¶
This package is a brotli compressor and decompressor implemented in Go.
It was translated from the reference implementation (https://github.com/google/brotli)
with the c2go tool at https://github.com/andybalholm/c2go.
I have been working on new compression algorithms (not translated from C) in the matchfinder package. You can use them with the NewWriterV2 function. Currently they give better results than the old implementation (at least for compressing my test file, Newton’s Opticks) on levels 2 to 6.
I am using it in production with https://github.com/andybalholm/redwood.
API documentation is found at https://pkg.go.dev/github.com/andybalholm/brotli?tab=doc.
Documentation
¶
Index ¶
Examples ¶
Constants ¶
const ( BestSpeed = 0 BestCompression = 11 DefaultCompression = 6 )
Variables ¶
This section is empty.
Functions ¶
func HTTPCompressor ¶
func HTTPCompressor(w http.ResponseWriter, r *http.Request) io.WriteCloser
HTTPCompressor chooses a compression method (brotli, gzip, or none) based on the Accept-Encoding header, sets the Content-Encoding header, and returns a WriteCloser that implements that compression. The Close method must be called before the current HTTP handler returns.
func NewWriterV2 ¶ added in v1.1.0
func NewWriterV2(dst io.Writer, level int) *matchfinder.Writer
NewWriterV2 is like NewWriterLevel, but it uses the new implementation based on the matchfinder package. It currently supports up to level 7; if a higher level is specified, level 7 will be used.
Types ¶
type Encoder ¶ added in v1.1.0
type Encoder struct {
// contains filtered or unexported fields
}
An Encoder implements the matchfinder.Encoder interface, writing in Brotli format.
type Reader ¶
type Reader struct {
// contains filtered or unexported fields
}
type Writer ¶
type Writer struct {
// contains filtered or unexported fields
}
func NewWriter ¶
Writes to the returned writer are compressed and written to dst. It is the caller's responsibility to call Close on the Writer 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 or any integer value between BestSpeed and BestCompression inclusive.
func NewWriterOptions ¶
func NewWriterOptions(dst io.Writer, options WriterOptions) *Writer
NewWriterOptions is like NewWriter but specifies WriterOptions
func (*Writer) Flush ¶
Flush outputs encoded data for all input provided to Write. The resulting output can be decoded to match all input before Flush, but the stream is not yet complete until after Close. Flush has a negative impact on compression.
func (*Writer) Reset ¶
Reset discards the Writer's state and makes it equivalent to the result of its original state from NewWriter or NewWriterLevel, but writing to dst instead. This permits reusing a Writer rather than allocating a new one.
Example ¶
proverbs := []string{
"Don't communicate by sharing memory, share memory by communicating.\n",
"Concurrency is not parallelism.\n",
"The bigger the interface, the weaker the abstraction.\n",
"Documentation is for users.\n",
}
var b bytes.Buffer
bw := NewWriter(nil)
br := NewReader(nil)
for _, s := range proverbs {
b.Reset()
// Reset the compressor and encode from some input stream.
bw.Reset(&b)
if _, err := io.WriteString(bw, s); err != nil {
log.Fatal(err)
}
if err := bw.Close(); err != nil {
log.Fatal(err)
}
// Reset the decompressor and decode to some output stream.
if err := br.Reset(&b); err != nil {
log.Fatal(err)
}
if _, err := io.Copy(os.Stdout, br); err != nil {
log.Fatal(err)
}
}
Output: Don't communicate by sharing memory, share memory by communicating. Concurrency is not parallelism. The bigger the interface, the weaker the abstraction. Documentation is for users.
type WriterOptions ¶
type WriterOptions struct {
// Quality controls the compression-speed vs compression-density trade-offs.
// The higher the quality, the slower the compression. Range is 0 to 11.
Quality int
// LGWin is the base 2 logarithm of the sliding window size.
// Range is 10 to 24. 0 indicates automatic configuration based on Quality.
LGWin int
}
WriterOptions configures Writer.
Source Files
¶
- backward_references.go
- backward_references_hq.go
- bit_cost.go
- bit_reader.go
- bitwriter.go
- block_splitter.go
- block_splitter_command.go
- block_splitter_distance.go
- block_splitter_literal.go
- brotli_bit_stream.go
- cluster.go
- cluster_command.go
- cluster_distance.go
- cluster_literal.go
- command.go
- compress_fragment.go
- compress_fragment_two_pass.go
- constants.go
- context.go
- decode.go
- dictionary.go
- dictionary_hash.go
- encode.go
- encoder.go
- encoder_dict.go
- entropy_encode.go
- entropy_encode_static.go
- fast_log.go
- find_match_length.go
- h10.go
- h5.go
- h6.go
- hash.go
- hash_composite.go
- hash_forgetful_chain.go
- hash_longest_match_quickly.go
- hash_rolling.go
- histogram.go
- http.go
- huffman.go
- literal_cost.go
- memory.go
- metablock.go
- metablock_command.go
- metablock_distance.go
- metablock_literal.go
- params.go
- platform.go
- prefix.go
- prefix_dec.go
- quality.go
- reader.go
- ringbuffer.go
- state.go
- static_dict.go
- static_dict_lut.go
- symbol_list.go
- transform.go
- utf8_util.go
- util.go
- write_bits.go
- writer.go
Directories
¶
| Path | Synopsis |
|---|---|
|
The matchfinder package defines reusable components for data compression.
|
The matchfinder package defines reusable components for data compression. |