1 files changed, 21 insertions, 26 deletions
diff --git a/libgo/go/archive/zip/register.go b/libgo/go/archive/zip/register.go
index 2e76386b1fd..51e9c3e4d4b 100644
--- a/libgo/go/archive/zip/register.go
+++ b/libgo/go/archive/zip/register.go
@@ -103,51 +103,46 @@ func (r *pooledFlateReader) Close() error {
 }
 
 var (
-	mu sync.RWMutex // guards compressor and decompressor maps
+	compressors   sync.Map // map[uint16]Compressor
+	decompressors sync.Map // map[uint16]Decompressor
+)
 
-	compressors = map[uint16]Compressor{
-		Store:   func(w io.Writer) (io.WriteCloser, error) { return &nopCloser{w}, nil },
-		Deflate: func(w io.Writer) (io.WriteCloser, error) { return newFlateWriter(w), nil },
-	}
+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 = map[uint16]Decompressor{
-		Store:   ioutil.NopCloser,
-		Deflate: newFlateReader,
-	}
-)
+	decompressors.Store(Store, Decompressor(ioutil.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) {
-	mu.Lock()
-	defer mu.Unlock()
-
-	if _, ok := decompressors[method]; ok {
+	if _, dup := decompressors.LoadOrStore(method, dcomp); dup {
 		panic("decompressor already registered")
 	}
-	decompressors[method] = dcomp
 }
 
 // RegisterCompressor registers custom compressors for a specified method ID.
 // The common methods Store and Deflate are built in.
 func RegisterCompressor(method uint16, comp Compressor) {
-	mu.Lock()
-	defer mu.Unlock()
-
-	if _, ok := compressors[method]; ok {
+	if _, dup := compressors.LoadOrStore(method, comp); dup {
 		panic("compressor already registered")
 	}
-	compressors[method] = comp
 }
 
 func compressor(method uint16) Compressor {
-	mu.RLock()
-	defer mu.RUnlock()
-	return compressors[method]
+	ci, ok := compressors.Load(method)
+	if !ok {
+		return nil
+	}
+	return ci.(Compressor)
 }
 
 func decompressor(method uint16) Decompressor {
-	mu.RLock()
-	defer mu.RUnlock()
-	return decompressors[method]
+	di, ok := decompressors.Load(method)
+	if !ok {
+		return nil
+	}
+	return di.(Decompressor)
 }