Use bytes.IndexByte() in ignoreComment() to find first '-'

combined_test.go

@@ -462,6 +462,41 @@ func BenchmarkLotsOfText(b *testing.B) {
 	}
 }
 
+func BenchmarkWithSkippedWhitespace(b *testing.B) {
+	r := strings.NewReader(
+		`
+<soap:Envelope
+xmlns:soap="http://www.w3.org/2003/05/soap-envelope/"
+soap:encodingStyle="http://www.w3.org/2003/05/soap-encoding">
+<soap:Body>
+  <m:GetPrice xmlns:m="https://www.w3schools.com/prices">
+    <!-- we want to add a <m:Item>Apples</m:Item> here -->
+  </m:GetPrice>
+</soap:Body>
+</soap:Envelope>`)
+	dec := gosaxml.NewDecoder(r)
+	enc := gosaxml.NewEncoder(io.Discard, gosaxml.NewNamespaceModifier())
+	var tk gosaxml.Token
+
+	b.ReportAllocs()
+	b.ResetTimer()
+
+	for i := 0; i < b.N; i++ {
+		_, err := r.Seek(0, io.SeekStart)
+		assert.Nil(b, err)
+		dec.Reset(r)
+		for {
+			err = dec.NextToken(&tk)
+			if err == io.EOF {
+				break
+			}
+			assert.Nil(b, err)
+			err = enc.EncodeToken(&tk)
+			assert.Nil(b, err)
+		}
+	}
+}
+
 func decodeEncode(t *testing.T, dec gosaxml.Decoder, enc *gosaxml.Encoder, tk *gosaxml.Token) {
 	for {
 		err := dec.NextToken(tk)

decoder.go

@@ -276,32 +276,40 @@ func (thiz *decoder) ignoreComment() error {
 		return err
 	}
 	for {
-		var b byte
-		b, err = thiz.readByte()
-		if err != nil {
-			return err
-		}
-		if b == '-' {
-			var b2 byte
-			b2, err = thiz.readByte()
-			if err != nil {
-				return err
-			}
-			if b2 == '-' {
-				for {
-					var b3 byte
-					b3, err = thiz.readByte()
-					if err != nil {
-						return err
-					}
-					if b3 == '>' {
-						return nil
-					} else if b3 != '-' {
-						break
+		for thiz.w > thiz.r {
+			k := bytes.IndexByte(thiz.rb[thiz.r:thiz.w], '-')
+			if k > -1 {
+				_, err = thiz.discard(k + 1)
+				if err != nil {
+					return err
+				}
+				var b2 byte
+				b2, err = thiz.readByte()
+				if err != nil {
+					return err
+				}
+				if b2 == '-' {
+					for {
+						var b3 byte
+						b3, err = thiz.readByte()
+						if err != nil {
+							return err
+						}
+						if b3 == '>' {
+							return nil
+						} else if b3 != '-' {
+							break
+						}
 					}
 				}
+			} else {
+				thiz.discardBuffer()
 			}
 		}
+		err := thiz.read0()
+		if err != nil {
+			return err
+		}
 	}
 }