old_contents: // Copyright (c) 2015 Uber Technologies, Inc.
  //
  // Permission is hereby granted, free of charge, to any person obtaining a copy
  // of this software and associated documentation files (the "Software"), to deal
  // in the Software without restriction, including without limitation the rights
  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  // copies of the Software, and to permit persons to whom the Software is
  // furnished to do so, subject to the following conditions:
  //
  // The above copyright notice and this permission notice shall be included in
  // all copies or substantial portions of the Software.
  //
  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  // THE SOFTWARE.
  
  'use strict';
  
  var Buffer = require('buffer').Buffer;
  
  // The batch message payload should follow:
  // 4 BE bytes number of messages + 4 BE bytes size of message + actual message
  function MessageBatch(size) {
      var self = this;
  
      self.cachedBuf = new Buffer(size);
      self.currOffset = 4;
      self.timestamp = new Date().getTime();
      self.numMessages = 0;
      self.sizeBytes = 4;
  }
  
  MessageBatch.prototype.addMessage = function addMessage(message, callback) {
      var self = this;
  
      var bytesWritten = 4;
      var offset = self.currOffset;
      var msgOffset = offset + 4;
  
      self.cachedBuf.writeInt32BE(bytesWritten, offset);
  
      if(typeof message == 'string') {
          bytesWritten += self.cachedBuf.write(message, msgOffset);
      } else if (Buffer.isBuffer(message)){
          // byte array message
          message.copy(self.cachedBuf, msgOffset);
          bytesWritten += message.length;
      } else {
          callback(new Error('For batching, message must be a string or buffer!'));
      }
  
      self.numMessages += 1;
      self.sizeBytes += bytesWritten;
      self.currOffset += 4 + bytesWritten;
  };
  
  MessageBatch.prototype.getBatchedMessage = function getBatchedMessage() {
      var self = this;
  
      self.cachedBuf.writeUInt32BE(self.numMessages, 0);
  
      return self.cachedBuf.slice(0, self.currOffset);
  };
  
  module.exports = MessageBatch;
  
  var messageBatch = new MessageBatch(100000);
  messageBatch.addMessage('This is a test.');
  messageBatch.addMessage('Foo');
  messageBatch.addMessage('Bar');
  var message = messageBatch.getBatchedMessage();
  console.log(typeof message.toJSON());
new_contents: // Copyright (c) 2015 Uber Technologies, Inc.
  //
  // Permission is hereby granted, free of charge, to any person obtaining a copy
  // of this software and associated documentation files (the "Software"), to deal
  // in the Software without restriction, including without limitation the rights
  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  // copies of the Software, and to permit persons to whom the Software is
  // furnished to do so, subject to the following conditions:
  //
  // The above copyright notice and this permission notice shall be included in
  // all copies or substantial portions of the Software.
  //
  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  // THE SOFTWARE.
  
  'use strict';
  
  var Buffer = require('buffer').Buffer;
  
  // The batch message payload should follow:
  // 4 BE bytes number of messages + 4 BE bytes size of message + actual message
  function MessageBatch(size) {
      var self = this;
  
      self.cachedBuf = new Buffer(size);
      self.currOffset = 4;
      self.timestamp = new Date().getTime();
      self.numMessages = 0;
      self.sizeBytes = 4;
  }
  
  MessageBatch.prototype.addMessage = function addMessage(message, callback) {
      var self = this;
  
      var bytesWritten = 4;
      var offset = self.currOffset;
      var msgOffset = offset + 4;
  
      self.cachedBuf.writeInt32BE(bytesWritten, offset);
  
      if(typeof message == 'string') {
          bytesWritten += self.cachedBuf.write(message, msgOffset);
      } else if (Buffer.isBuffer(message)){
          // byte array message
          message.copy(self.cachedBuf, msgOffset);
          bytesWritten += message.length;
      } else {
          callback(new Error('For batching, message must be a string or buffer!'));
      }
  
      self.numMessages += 1;
      self.sizeBytes += bytesWritten;
      self.currOffset += 4 + bytesWritten;
  };
  
  MessageBatch.prototype.getBatchedMessage = function getBatchedMessage() {
      var self = this;
  
      self.cachedBuf.writeUInt32BE(self.numMessages, 0);
  
      return self.cachedBuf.slice(0, self.currOffset);
  };
  
  module.exports = MessageBatch;
  
subject: Update message_batch.js