Int switch

sdk/lib/io/http_headers.dart

Index: sdk/lib/io/http_headers.dart
diff --git a/sdk/lib/io/http_headers.dart b/sdk/lib/io/http_headers.dart
index 33d51373a121331ab282ca78dcb6a0916ccfe185..14a34853bee0577b262987823dd1bca903dae153 100644
--- a/sdk/lib/io/http_headers.dart
+++ b/sdk/lib/io/http_headers.dart
@@ -338,25 +338,53 @@ class _HttpHeaders implements HttpHeaders {
     headers._set(HttpHeaders.CONTENT_TYPE, value);
   }
 
-  // TODO(ajohnsen): Change to const map, once const maps are faster.
-  static final _addMap = {
-    HttpHeaders.CONTENT_LENGTH: _addContentLength,
-    HttpHeaders.TRANSFER_ENCODING: _addTransferEncoding,
-    HttpHeaders.DATE: _addDate,
-    HttpHeaders.EXPIRES: _addExpires,
-    HttpHeaders.IF_MODIFIED_SINCE: _addIfModifiedSince,
-    HttpHeaders.HOST: _addHost,
-    HttpHeaders.CONNECTION: _addConnection,
-    HttpHeaders.CONTENT_TYPE: _addContentType
-  };
-
   // [name] must be a lower-case version of the name.
   void _add(String name, value) {
     assert(name == name.toLowerCase());

[Søren Gjesse, 2014/04/23 12:06:39]

Please add a comment on this optimization.

[Anders Johnsen, 2014/04/23 12:20:12]

Done.

-    var method = _addMap[name];
-    if (method != null) {
-      method(this, name, value);
-      return;
+    switch (name.length) {
+      case 4:
+        if (HttpHeaders.DATE == name) {
+          _addDate(this, name, value);

[Anders Johnsen, 2014/04/23 11:57:05]

Should we merge return into this line?

[Søren Gjesse, 2014/04/23 12:06:39]

Don't think so.

+          return;
+        }
+        if (HttpHeaders.HOST == name) {
+          _addHost(this, name, value);
+          return;
+        }
+        break;
+      case 7:
+        if (HttpHeaders.EXPIRES == name) {
+          _addExpires(this, name, value);
+          return;
+        }
+        break;
+      case 10:
+        if (HttpHeaders.CONNECTION == name) {
+          _addConnection(this, name, value);
+          return;
+        }
+        break;
+      case 12:
+        if (HttpHeaders.CONTENT_TYPE == name) {
+          _addContentType(this, name, value);
+          return;
+        }
+        break;
+      case 14:
+        if (HttpHeaders.CONTENT_LENGTH == name) {
+          _addContentLength(this, name, value);
+          return;
+        }
+        break;
+      case 17:
+        if (HttpHeaders.TRANSFER_ENCODING == name) {
+          _addTransferEncoding(this, name, value);
+          return;
+        }
+        if (HttpHeaders.IF_MODIFIED_SINCE == name) {
+          _addIfModifiedSince(this, name, value);
+          return;
+        }
     }
     _addValue(name, value);
   }