use map for ignored extensions

ginzip.go

@@ -33,7 +33,7 @@ type intOptions struct {
 	GzipLevel      int
 	BrotliEn       bool
 	BrotliLevel    int
-	SkipExtensions []string
+	SkipExtensions map[string]bool
 }
 
 // New creates a new Ginzip middleware function.
@@ -136,16 +136,7 @@ func (b *brotliWriter) Encoding() string {
 	return "br"
 }
 
-func containsString(s []string, e string) bool {
-	for _, a := range s {
-		if a == e {
-			return true
-		}
-	}
-	return false
-}
-
-func shouldCompress(req *http.Request, skipExtensions []string) bool {
+func shouldCompress(req *http.Request, skipExtensions map[string]bool) bool {
 	// Dont compress websocket connections
 	if strings.Contains(req.Header.Get("Connection"), "Upgrade") ||
 		strings.Contains(req.Header.Get("Content-Type"), "text/event-stream") {
@@ -157,7 +148,8 @@ func shouldCompress(req *http.Request, skipExtensions []string) bool {
 		return true
 	}
 
-	return !containsString(skipExtensions, extension)
+	_, doSkip := skipExtensions[extension]
+	return !doSkip
 }
 
 func parseLevel(level string, dfault int, min int, max int) (int, bool) {
@@ -193,12 +185,17 @@ func parseOptions(options Options) intOptions {
 		brotli.DefaultCompression, brotli.BestSpeed, brotli.BestCompression,
 	)
 
+	exts := map[string]bool{}
+	for _, ext := range options.SkipExtensions {
+		exts[ext] = true
+	}
+
 	return intOptions{
 		GzipEn:         gzipEn,
 		GzipLevel:      gzipLvl,
 		BrotliEn:       brEn,
 		BrotliLevel:    brLvl,
-		SkipExtensions: options.SkipExtensions,
+		SkipExtensions: exts,
 	}
 }