/
compress_zlib.go
83 lines (65 loc) · 1.69 KB
/
compress_zlib.go
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package compress
import (
"bytes"
"compress/zlib"
"io"
"github.com/jumper86/jumper_transform/def"
"github.com/jumper86/jumper_transform/interf"
"github.com/jumper86/jumper_transform/util"
)
type compressOpZlib struct {
}
func NewcompressOpZlib(params []interface{}) interf.CompressOp {
var op compressOpZlib
op.init(params)
return &op
}
func (self *compressOpZlib) init(params []interface{}) bool {
return true
}
func (self *compressOpZlib) Operate(direct int8, input interface{}, output interface{}) (bool, error) {
if direct == def.Forward {
tmpOutput, err := self.Compress(input.([]byte))
if err != nil {
return false, err
}
*(output.(*[]byte)) = tmpOutput
return true, nil
} else {
tmpOutput, err := self.Decompress(input.([]byte))
if err != nil {
return false, err
}
*(output.(*[]byte)) = tmpOutput
return true, nil
}
return true, nil
}
func (self *compressOpZlib) Compress(data []byte) ([]byte, error) {
defer util.TraceLog("compressOpZlib.Compress")()
var buf bytes.Buffer
c := zlib.NewWriter(&buf)
_, err := c.Write(data)
if err != nil {
return nil, err
}
//note:若是上面使用 defer c.Close() 会导致在下面解压时出现错误: decompress err: unexpected EOF, 使用c.Close则不会
//但是对于decompress 中的 reader 却可以defer close
c.Close()
return buf.Bytes(), nil
}
func (self *compressOpZlib) Decompress(data []byte) ([]byte, error) {
defer util.TraceLog("compressOpZlib.Decompress")()
nr := bytes.NewReader(data)
dc, err := zlib.NewReader(nr)
if err != nil {
return nil, err
}
defer dc.Close()
var buf bytes.Buffer
_, err = io.Copy(&buf, dc)
if err != nil {
return nil, err
}
return buf.Bytes(), nil
}