github.com/vicanso/pike@v1.0.1-0.20210630235453-9099e041f6ec/compress/brotli.go (about)

     1  // MIT License
     2  
     3  // Copyright (c) 2020 Tree Xie
     4  
     5  // Permission is hereby granted, free of charge, to any person obtaining a copy
     6  // of this software and associated documentation files (the "Software"), to deal
     7  // in the Software without restriction, including without limitation the rights
     8  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
     9  // copies of the Software, and to permit persons to whom the Software is
    10  // furnished to do so, subject to the following conditions:
    11  
    12  // The above copyright notice and this permission notice shall be included in all
    13  // copies or substantial portions of the Software.
    14  
    15  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    16  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    17  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    18  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    19  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    20  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
    21  // SOFTWARE.
    22  
    23  package compress
    24  
    25  import (
    26  	"bytes"
    27  	"io/ioutil"
    28  
    29  	"github.com/andybalholm/brotli"
    30  )
    31  
    32  const (
    33  	defaultBrQuality = 6
    34  )
    35  
    36  func brotliEncode(buf []byte, level int) (*bytes.Buffer, error) {
    37  	buffer := new(bytes.Buffer)
    38  	if level <= 0 || level > 11 {
    39  		level = defaultBrQuality
    40  	}
    41  	w := brotli.NewWriterLevel(buffer, level)
    42  	defer w.Close()
    43  	_, err := w.Write(buf)
    44  	if err != nil {
    45  		return nil, err
    46  	}
    47  	return buffer, nil
    48  }
    49  
    50  // doBrotli brotli compress
    51  func doBrotli(buf []byte, level int) ([]byte, error) {
    52  	buffer, err := brotliEncode(buf, level)
    53  	if err != nil {
    54  		return nil, err
    55  	}
    56  	return buffer.Bytes(), nil
    57  }
    58  
    59  // doBrotliDecode brotli decode
    60  func doBrotliDecode(buf []byte) ([]byte, error) {
    61  	if len(buf) == 0 {
    62  		return nil, nil
    63  	}
    64  	r := brotli.NewReader(bytes.NewBuffer(buf))
    65  	return ioutil.ReadAll(r)
    66  }