File size: 3,750 Bytes
da86720 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 | // Copyright 2010 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package zip
import (
"compress/flate"
"errors"
"io"
"sync"
)
// A Compressor returns a new compressing writer, writing to w.
// The WriteCloser's Close method must be used to flush pending data to w.
// The Compressor itself must be safe to invoke from multiple goroutines
// simultaneously, but each returned writer will be used only by
// one goroutine at a time.
type Compressor func(w io.Writer) (io.WriteCloser, error)
// A Decompressor returns a new decompressing reader, reading from r.
// The [io.ReadCloser]'s Close method must be used to release associated resources.
// The Decompressor itself must be safe to invoke from multiple goroutines
// simultaneously, but each returned reader will be used only by
// one goroutine at a time.
type Decompressor func(r io.Reader) io.ReadCloser
var flateWriterPool sync.Pool
func newFlateWriter(w io.Writer) io.WriteCloser {
fw, ok := flateWriterPool.Get().(*flate.Writer)
if ok {
fw.Reset(w)
} else {
fw, _ = flate.NewWriter(w, 5)
}
return &pooledFlateWriter{fw: fw}
}
type pooledFlateWriter struct {
mu sync.Mutex // guards Close and Write
fw *flate.Writer
}
func (w *pooledFlateWriter) Write(p []byte) (n int, err error) {
w.mu.Lock()
defer w.mu.Unlock()
if w.fw == nil {
return 0, errors.New("Write after Close")
}
return w.fw.Write(p)
}
func (w *pooledFlateWriter) Close() error {
w.mu.Lock()
defer w.mu.Unlock()
var err error
if w.fw != nil {
err = w.fw.Close()
flateWriterPool.Put(w.fw)
w.fw = nil
}
return err
}
var flateReaderPool sync.Pool
func newFlateReader(r io.Reader) io.ReadCloser {
fr, ok := flateReaderPool.Get().(io.ReadCloser)
if ok {
fr.(flate.Resetter).Reset(r, nil)
} else {
fr = flate.NewReader(r)
}
return &pooledFlateReader{fr: fr}
}
type pooledFlateReader struct {
mu sync.Mutex // guards Close and Read
fr io.ReadCloser
}
func (r *pooledFlateReader) Read(p []byte) (n int, err error) {
r.mu.Lock()
defer r.mu.Unlock()
if r.fr == nil {
return 0, errors.New("Read after Close")
}
return r.fr.Read(p)
}
func (r *pooledFlateReader) Close() error {
r.mu.Lock()
defer r.mu.Unlock()
var err error
if r.fr != nil {
err = r.fr.Close()
flateReaderPool.Put(r.fr)
r.fr = nil
}
return err
}
var (
compressors sync.Map // map[uint16]Compressor
decompressors sync.Map // map[uint16]Decompressor
)
func init() {
compressors.Store(Store, Compressor(func(w io.Writer) (io.WriteCloser, error) { return &nopCloser{w}, nil }))
compressors.Store(Deflate, Compressor(func(w io.Writer) (io.WriteCloser, error) { return newFlateWriter(w), nil }))
decompressors.Store(Store, Decompressor(io.NopCloser))
decompressors.Store(Deflate, Decompressor(newFlateReader))
}
// RegisterDecompressor allows custom decompressors for a specified method ID.
// The common methods [Store] and [Deflate] are built in.
func RegisterDecompressor(method uint16, dcomp Decompressor) {
if _, dup := decompressors.LoadOrStore(method, dcomp); dup {
panic("decompressor already registered")
}
}
// RegisterCompressor registers custom compressors for a specified method ID.
// The common methods [Store] and [Deflate] are built in.
func RegisterCompressor(method uint16, comp Compressor) {
if _, dup := compressors.LoadOrStore(method, comp); dup {
panic("compressor already registered")
}
}
func compressor(method uint16) Compressor {
ci, ok := compressors.Load(method)
if !ok {
return nil
}
return ci.(Compressor)
}
func decompressor(method uint16) Decompressor {
di, ok := decompressors.Load(method)
if !ok {
return nil
}
return di.(Decompressor)
}
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