Replace switch with if/else when processing whitespace. If/else is faster!

Author: swankjesse

gson/src/main/java/com/google/gson/stream/JsonReader.java

@@ -1312,14 +1312,11 @@ private int nextNonWhitespace(boolean throwOnEof) throws IOException {
       }
 
       int c = buffer[p++];
-      switch (c) {
-      case '\t':
-      case ' ':
-      case '\n':
-      case '\r':
+      if (c == ' ' || c == '\n' || c == '\r' || c == '\t') {
         continue;
+      }
 
-      case '/':
+      if (c == '/') {
         pos = p;
         if (p == l) {
           pos--; // push back '/' so it's still in the buffer when this method returns
@@ -1354,8 +1351,7 @@ private int nextNonWhitespace(boolean throwOnEof) throws IOException {
         default:
           return c;
         }
-
-      case '#':
+      } else if (c == '#') {
         pos = p;
         /*
          * Skip a # hash end-of-line comment. The JSON RFC doesn't
@@ -1366,9 +1362,7 @@ private int nextNonWhitespace(boolean throwOnEof) throws IOException {
         skipToEndOfLine();
         p = pos;
         l = limit;
-        continue;
-
-      default:
+      } else {
         pos = p;
         return c;
       }

metrics/src/main/java/com/google/gson/metrics/ParseBenchmark.java

@@ -146,45 +146,41 @@ public void parse(char[] data, Document document) throws Exception {
       jsonReader.close();
     }
 
-    public void readObject(com.google.gson.stream.JsonReader reader) throws IOException {
-      reader.beginObject();
-      while (reader.hasNext()) {
-        reader.nextName();
-        readToken(reader);
-      }
-      reader.endObject();
-    }
-
-    public void readArray(com.google.gson.stream.JsonReader reader) throws IOException {
-      reader.beginArray();
-      while (reader.hasNext()) {
-        readToken(reader);
-      }
-      reader.endArray();
-    }
-
     private void readToken(com.google.gson.stream.JsonReader reader) throws IOException {
-      switch (reader.peek()) {
-      case BEGIN_ARRAY:
-        readArray(reader);
-        break;
-      case BEGIN_OBJECT:
-        readObject(reader);
-        break;
-      case BOOLEAN:
-        reader.nextBoolean();
-        break;
-      case NULL:
-        reader.nextNull();
-        break;
-      case NUMBER:
-        reader.nextLong();
-        break;
-      case STRING:
-        reader.nextString();
-        break;
-      default:
-        throw new IllegalArgumentException("Unexpected token" + reader.peek());
+      while (true) {
+        switch (reader.peek()) {
+        case BEGIN_ARRAY:
+          reader.beginArray();
+          break;
+        case END_ARRAY:
+          reader.endArray();
+          break;
+        case BEGIN_OBJECT:
+          reader.beginObject();
+          break;
+        case END_OBJECT:
+          reader.endObject();
+          break;
+        case NAME:
+          reader.nextName();
+          break;
+        case BOOLEAN:
+          reader.nextBoolean();
+          break;
+        case NULL:
+          reader.nextNull();
+          break;
+        case NUMBER:
+          reader.nextLong();
+          break;
+        case STRING:
+          reader.nextString();
+          break;
+        case END_DOCUMENT:
+          return;
+        default:
+          throw new IllegalArgumentException("Unexpected token" + reader.peek());
+        }
       }
     }
   }