Fix: matchfinder Encode method bug

When the close method of WriterV2 is called and there is no data in inBuf, it writes additional data beyond the ending.

encoder.go

@@ -20,6 +20,15 @@ func (e *Encoder) Encode(dst []byte, src []byte, matches []matchfinder.Match, la
 		e.bw.writeBits(4, 15)
 		e.wroteHeader = true
 	}
+	//
+	if len(src) == 0 {
+		if lastBlock {
+			e.bw.writeBits(2, 3) // islast + isempty
+			e.bw.jumpToByteBoundary()
+			return e.bw.dst
+		}
+		return nil
+	}
 
 	var literalHisto [256]uint32
 	var commandHisto [704]uint32

matchfinder/matchfinder.go

@@ -10,7 +10,9 @@
 // representation to allow mixing and matching compression components.
 package matchfinder
 
-import "io"
+import (
+	"io"
+)
 
 // A Match is the basic unit of LZ77 compression.
 type Match struct {
@@ -79,8 +81,14 @@ func (w *Writer) Write(p []byte) (n int, err error) {
 }
 
 func (w *Writer) writeBlock(p []byte, lastBlock bool) (n int, err error) {
+	if len(p) == 0 {
+		if !lastBlock {
+			return
+		}
+	} else {
+		w.matches = w.MatchFinder.FindMatches(w.matches[:0], p)
+	}
 	w.outBuf = w.outBuf[:0]
-	w.matches = w.MatchFinder.FindMatches(w.matches[:0], p)
 	w.outBuf = w.Encoder.Encode(w.outBuf, p, w.matches, lastBlock)
 	_, w.err = w.Dest.Write(w.outBuf)
 	return len(p), w.err

matchfinder/textencoder.go

@@ -9,6 +9,9 @@ type TextEncoder struct{}
 func (t TextEncoder) Reset() {}
 
 func (t TextEncoder) Encode(dst []byte, src []byte, matches []Match, lastBlock bool) []byte {
+	if len(src) == 0 {
+		return nil
+	}
 	pos := 0
 	for _, m := range matches {
 		if m.Unmatched > 0 {