simplify and fix entityMetadata parsing and serializing

README.md

@@ -112,27 +112,16 @@ server.on('login', function(client) {
 
 #### entityMetadata
 
-When *writing* a packet with an entityMetadata data type field, the structure
-looks like this:
+Value looks like this:
 
 ```js
 [
-  {type: 'slot', value: slot},
-  {type: 'int', value: value},
+  {type: 'slot', value: slot, key: 3},
+  {type: 'int', value: value, key: 4},
   ...
 ]
 ```
 
-When *receiving* a packet with an entityMetadata data type field, the structure
-looks like this:
-
-```js
-{
-  1: value,
-  3: value,
-}
-```
-
 Where the key is the numeric metadata key and the value is the value of the 
 correct data type.
 

lib/protocol.js

@@ -510,30 +510,33 @@ for (var n in entityMetadataTypes) {
 
 function EntityMetadataWriter(value) {
   this.value = [];
-  this.size = 1;
-  value.forEach(function(item) {
-    this.size += 1;
-    var Writer = types[item.type][1];
+  this.size = 1 + value.length;
+  var item, Writer, writer, dataType;
+  for (var i = 0; i < value.length; ++i) {
+    item = value[i];
+    dataType = types[item.type];
+    assert.ok(dataType, "unknown data type " + dataType);
+    Writer = dataType[1];
     assert.ok(Writer, "missing writer for data type " + item.type);
-    var writer = new Writer(item.value);
+    writer = new Writer(item.value);
     this.size += writer.size;
     this.value.push({
       writer: writer,
       key: item.key,
       type: entityMetadataTypeBytes[item.type],
     });
-  });
+  }
 }
 
 EntityMetadataWriter.prototype.write = function(buffer, offset) {
   this.value.forEach(function(item) {
-    var headerByte = (item.type << 5) & item.key;
-    buffer.write(headerByte, offset);
+    var headerByte = (item.type << 5) | item.key;
+    buffer.writeUInt8(headerByte, offset);
     offset += 1;
     item.writer.write(buffer, offset);
     offset += item.writer.size;
   });
-  buffer.writeUInt8(127, offset);
+  buffer.writeUInt8(0x7f, offset);
 }
 
 function ObjectDataWriter(value) {
@@ -708,26 +711,34 @@ function readIntVector(buffer, offset) {
 
 function readEntityMetadata(buffer, offset) {
   var cursor = offset;
-  var metadata = {};
-  var item, key, type, results, reader;
+  var metadata = [];
+  var item, key, type, results, reader, typeName, dataType;
   while (true) {
     if (cursor + 1 > buffer.length) return null;
     item = buffer.readUInt8(cursor);
     cursor += 1;
-    if (item === 0x7f) break;
+    if (item === 0x7f) {
+      return {
+        value: metadata,
+        size: cursor - offset,
+      };
+    }
     key = item & 0x1f;
     type = item >> 5;
-    reader = types[entityMetadataTypes[type]][0];
+    typeName = entityMetadataTypes[type];
+    dataType = types[typeName];
+    assert.ok(dataType, "unrecognized entity metadata type " + type);
+    reader = dataType[0];
     assert.ok(reader, "missing reader for entity metadata type " + type);
     results = reader(buffer, cursor);
     if (! results) return null;
-    metadata[key] = results.value;
+    metadata.push({
+      key: key,
+      value: results.value,
+      type: typeName,
+    });
     cursor += results.size;
   }
-  return {
-    value: metadata,
-    size: cursor - offset,
-  };
 }
 
 function readObjectData(buffer, offset) {

test/test.js

@@ -86,7 +86,11 @@ var values = {
       addBitMap: 10,
     }],
   }, ok],
-  'entityMetadata': [[], ok],
+  'entityMetadata': [[{
+    type: 'int',
+    key: 3,
+    value: 100,
+  }], ok],
   'objectData': [{
     intField: 9,
     velocityX: 1,
@@ -153,11 +157,6 @@ describe("packets", function() {
         assertPacketsMatch(receivedPacket, clientReceivedPacket);
         done();
       });
-      // entityMetadata does not have the same format sending and receiving
-      // we skip the test.
-      if (receivedPacket.metadata) {
-        return done();
-      }
       serverClient.write(packetId, receivedPacket);
     });
     client.write(packetId, packet);