add a comment explaining backwards compatibility

rathann · rathann · commit 25e050dbb4e3 · 2020-10-28T09:06:03.000+01:00
diff --git a/lz4.go b/lz4.go
@@ -16,6 +16,8 @@ type Lz4 struct {
 // Compress reads in, compresses it, and writes it to out.
 func (lz *Lz4) Compress(in io.Reader, out io.Writer) error {
 	w := lz4.NewWriter(out)
+	// TODO archiver v4: use proper lz4.Fast
+	// bitshifting for backwards compatibility with lz4/v3
 	options := []lz4.Option{
 		lz4.CompressionLevelOption(lz4.CompressionLevel(1 << (8 + lz.CompressionLevel))),
 	}
diff --git a/tarlz4.go b/tarlz4.go
@@ -84,6 +84,8 @@ func (tlz4 *TarLz4) wrapWriter() {
 	var lz4w *lz4.Writer
 	tlz4.Tar.writerWrapFn = func(w io.Writer) (io.Writer, error) {
 		lz4w = lz4.NewWriter(w)
+		// TODO archiver v4: use proper lz4.Fast
+		// bitshifting for backwards compatibility with lz4/v3
 		options := []lz4.Option{
 			lz4.CompressionLevelOption(lz4.CompressionLevel(1 << (8 + tlz4.CompressionLevel))),
 		}

Original file line number	Diff line number	Diff line change
`@@ -16,6 +16,8 @@ type Lz4 struct {`
`16`	`16`	`// Compress reads in, compresses it, and writes it to out.`
`17`	`17`	`func (lz *Lz4) Compress(in io.Reader, out io.Writer) error {`
`18`	`18`	`w := lz4.NewWriter(out)`
	`19`	`+ // TODO archiver v4: use proper lz4.Fast`
	`20`	`+ // bitshifting for backwards compatibility with lz4/v3`
`19`	`21`	`options := []lz4.Option{`
`20`	`22`	`lz4.CompressionLevelOption(lz4.CompressionLevel(1 << (8 + lz.CompressionLevel))),`
`21`	`23`	`}`
Original file line number	Diff line number	Diff line change
`@@ -84,6 +84,8 @@ func (tlz4 *TarLz4) wrapWriter() {`
`84`	`84`	`var lz4w *lz4.Writer`
`85`	`85`	`tlz4.Tar.writerWrapFn = func(w io.Writer) (io.Writer, error) {`
`86`	`86`	`lz4w = lz4.NewWriter(w)`
	`87`	`+ // TODO archiver v4: use proper lz4.Fast`
	`88`	`+ // bitshifting for backwards compatibility with lz4/v3`
`87`	`89`	`options := []lz4.Option{`
`88`	`90`	`lz4.CompressionLevelOption(lz4.CompressionLevel(1 << (8 + tlz4.CompressionLevel))),`
`89`	`91`	`}`