Add support for CBOR encoding

package.json

@@ -38,6 +38,7 @@
     "pngparse": "^2.0.1",
     "ws": "^1.1.1",
     "xmldom": "^0.1.19",
+    "cbor-js": "^0.1.0",
     "socket.io": "1.4.8"
   },
   "directories": {

src/core/Ros.js

@@ -70,7 +70,9 @@ Ros.prototype.connect = function(url) {
   } else if (this.transportLibrary.constructor.name === 'RTCPeerConnection') {
     this.socket = assign(this.transportLibrary.createDataChannel(url, this.transportOptions), socketAdapter(this));
   }else {
-    this.socket = assign(new WebSocket(url), socketAdapter(this));
+    var sock = new WebSocket(url);
+    sock.binaryType = 'arraybuffer';
+    this.socket = assign(sock, socketAdapter(this));
   }
 
 };

src/core/SocketAdapter.js

@@ -9,6 +9,8 @@
 'use strict';
 
 var decompressPng = require('../util/decompressPng');
+var CBOR = require('cbor-js');
+var typedArrayTagger = require('../util/cborTypedArrayTags');
 var WebSocket = require('ws');
 var BSON = null;
 if(typeof bson !== 'undefined'){
@@ -106,6 +108,9 @@ function SocketAdapter(client) {
         decodeBSON(data.data, function (message) {
           handlePng(message, handleMessage);
         });
+      } else if (data.data instanceof ArrayBuffer) {
+        var decoded = CBOR.decode(data.data, typedArrayTagger);
+        handleMessage(decoded);
       } else {
         var message = JSON.parse(typeof data === 'string' ? data : data.data);
         handlePng(message, handleMessage);

src/core/Topic.js

@@ -18,7 +18,7 @@ var Message = require('./Message');
  *   * ros - the ROSLIB.Ros connection handle
  *   * name - the topic name, like /cmd_vel
  *   * messageType - the message type, like 'std_msgs/String'
- *   * compression - the type of compression to use, like 'png'
+ *   * compression - the type of compression to use, like 'png' or 'cbor'
  *   * throttle_rate - the rate (in ms in between messages) at which to throttle the topics
  *   * queue_size - the queue created at bridge side for re-publishing webtopics (defaults to 100)
  *   * latch - latch the topic when publishing
@@ -40,7 +40,7 @@ function Topic(options) {
 
   // Check for valid compression types
   if (this.compression && this.compression !== 'png' &&
-    this.compression !== 'none') {
+    this.compression !== 'cbor' && this.compression !== 'none') {
     this.emit('warning', this.compression +
       ' compression is not supported. No compression will be used.');
   }

src/util/cborTypedArrayTags.js

@@ -0,0 +1,113 @@
+var UPPER32 = Math.pow(2, 32);
+
+var warnedPrecision = false;
+function warnPrecision() {
+  if (!warnedPrecision) {
+    warnedPrecision = true;
+    console.warn('CBOR 64-bit integer array values may lose precision. No further warnings.');
+  }
+}
+
+/**
+ * Unpacks 64-bit unsigned integer from byte array.
+ * @param {Uint8Array} bytes
+*/
+function decodeUint64LE(bytes) {
+  warnPrecision();
+
+  var byteLen = bytes.byteLength;
+  var arrLen = byteLen / 8;
+
+  var buffer = bytes.buffer.slice(-byteLen);
+  var uint32View = new Uint32Array(buffer);
+
+  var arr = new Array(arrLen);
+  for (var i = 0; i < arrLen; i++) {
+    var si = i * 2;
+    var lo = uint32View[si];
+    var hi = uint32View[si+1];
+    arr[i] = lo + UPPER32 * hi;
+  }
+
+  return arr;
+}
+
+/**
+ * Unpacks 64-bit signed integer from byte array.
+ * @param {Uint8Array} bytes
+*/
+function decodeInt64LE(bytes) {
+  warnPrecision();
+
+  var byteLen = bytes.byteLength;
+  var arrLen = byteLen / 8;
+
+  var buffer = bytes.buffer.slice(-byteLen);
+  var uint32View = new Uint32Array(buffer);
+  var int32View = new Int32Array(buffer);
+
+  var arr = new Array(arrLen);
+  for (var i = 0; i < arrLen; i++) {
+    var si = i * 2;
+    var lo = uint32View[si];
+    var hi = int32View[si+1];
+    arr[i] = lo + UPPER32 * hi;
+  }
+
+  return arr;
+}
+
+/**
+ * Unpacks typed array from byte array.
+ * @param {Uint8Array} bytes
+ * @param {type} ArrayType - desired output array type
+*/
+function decodeNativeArray(bytes, ArrayType) {
+  var byteLen = bytes.byteLength;
+  var buffer = bytes.buffer.slice(-byteLen);
+  return new ArrayType(buffer);
+}
+
+/**
+ * Support a subset of draft CBOR typed array tags:
+ *   <https://tools.ietf.org/html/draft-ietf-cbor-array-tags-00>
+ * Only support little-endian tags for now.
+ */
+var nativeArrayTypes = {
+  64: Uint8Array,
+  69: Uint16Array,
+  70: Uint32Array,
+  72: Int8Array,
+  77: Int16Array,
+  78: Int32Array,
+  85: Float32Array,
+  86: Float64Array
+};
+
+/**
+ * We can also decode 64-bit integer arrays, since ROS has these types.
+ */
+var conversionArrayTypes = {
+  71: decodeUint64LE,
+  79: decodeInt64LE
+};
+
+/**
+ * Handles CBOR typed array tags during decoding.
+ * @param {Uint8Array} data
+ * @param {Number} tag
+ */
+function cborTypedArrayTagger(data, tag) {
+  if (tag in nativeArrayTypes) {
+    var arrayType = nativeArrayTypes[tag];
+    return decodeNativeArray(data, arrayType);
+  }
+  if (tag in conversionArrayTypes) {
+    return conversionArrayTypes[tag](data);
+  }
+  return data;
+}
+
+if (typeof module !== 'undefined' && module.exports) {
+  module.exports = cborTypedArrayTagger;
+}

test/cbor.test.js

@@ -0,0 +1,115 @@
+var expect = require('chai').expect;
+var CBOR = require('cbor-js');
+var cborTypedArrayTagger = require('../src/util/cborTypedArrayTags.js');
+
+/** Convert hex string to ArrayBuffer. */
+function hexToBuffer(hex) {
+  var tokens = hex.match(/[0-9a-fA-F]{2}/gi);
+  var arr = tokens.map(function(t) {
+    return parseInt(t, 16);
+  });
+  return new Uint8Array(arr).buffer;
+}
+
+
+describe('CBOR Typed Array Tagger', function() {
+
+  it('should convert tagged Uint16Array', function() {
+    var data = hexToBuffer('d84546010002000300');
+    var msg = CBOR.decode(data, cborTypedArrayTagger);
+
+    expect(msg).to.be.a('Uint16Array');
+    expect(msg).to.have.lengthOf(3);
+    expect(msg[0]).to.equal(1);
+    expect(msg[1]).to.equal(2);
+    expect(msg[2]).to.equal(3);
+  });
+
+  it('should convert tagged Uint32Array', function() {
+    var data = hexToBuffer('d8464c010000000200000003000000');
+    var msg = CBOR.decode(data, cborTypedArrayTagger);
+
+    expect(msg).to.be.a('Uint32Array');
+    expect(msg).to.have.lengthOf(3);
+    expect(msg[0]).to.equal(1);
+    expect(msg[1]).to.equal(2);
+    expect(msg[2]).to.equal(3);
+  });
+
+  it('should convert tagged Uint64Array', function() {
+    var data = hexToBuffer('d8475818010000000000000002000000000000000300000000000000');
+    var msg = CBOR.decode(data, cborTypedArrayTagger);
+
+    expect(msg).to.be.a('Array');
+    expect(msg).to.have.lengthOf(3);
+    expect(msg[0]).to.equal(1);
+    expect(msg[1]).to.equal(2);
+    expect(msg[2]).to.equal(3);
+  });
+
+  it('should convert tagged Int8Array', function() {
+    var data = hexToBuffer('d8484301fe03');
+    var msg = CBOR.decode(data, cborTypedArrayTagger);
+
+    expect(msg).to.be.a('Int8Array');
+    expect(msg).to.have.lengthOf(3);
+    expect(msg[0]).to.equal(1);
+    expect(msg[1]).to.equal(-2);
+    expect(msg[2]).to.equal(3);
+  });
+
+  it('should convert tagged Int16Array', function() {
+    var data = hexToBuffer('d84d460100feff0300');
+    var msg = CBOR.decode(data, cborTypedArrayTagger);
+
+    expect(msg).to.be.a('Int16Array');
+    expect(msg).to.have.lengthOf(3);
+    expect(msg[0]).to.equal(1);
+    expect(msg[1]).to.equal(-2);
+    expect(msg[2]).to.equal(3);
+  });
+
+  it('should convert tagged Int32Array', function() {
+    var data = hexToBuffer('d84e4c01000000feffffff03000000');
+    var msg = CBOR.decode(data, cborTypedArrayTagger);
+
+    expect(msg).to.be.a('Int32Array');
+    expect(msg).to.have.lengthOf(3);
+    expect(msg[0]).to.equal(1);
+    expect(msg[1]).to.equal(-2);
+    expect(msg[2]).to.equal(3);
+  });
+
+  it('should convert tagged Int64Array', function() {
+    var data = hexToBuffer('d84f58180100000000000000feffffffffffffff0300000000000000');
+    var msg = CBOR.decode(data, cborTypedArrayTagger);
+
+    expect(msg).to.be.a('Array');
+    expect(msg).to.have.lengthOf(3);
+    expect(msg[0]).to.equal(1);
+    expect(msg[1]).to.equal(-2);
+    expect(msg[2]).to.equal(3);
+  });
+
+  it('should convert tagged Float32Array', function() {
+    var data = hexToBuffer('d8554ccdcc8c3fcdcc0cc033335340');
+    var msg = CBOR.decode(data, cborTypedArrayTagger);
+
+    expect(msg).to.be.a('Float32Array');
+    expect(msg).to.have.lengthOf(3);
+    expect(msg[0]).to.closeTo(1.1, 1e-5);
+    expect(msg[1]).to.closeTo(-2.2, 1e-5);
+    expect(msg[2]).to.closeTo(3.3, 1e-5);
+  });
+
+  it('should convert tagged Float64Array', function() {
+    var data = hexToBuffer('d85658189a9999999999f13f9a999999999901c06666666666660a40');
+    var msg = CBOR.decode(data, cborTypedArrayTagger);
+
+    expect(msg).to.be.a('Float64Array');
+    expect(msg).to.have.lengthOf(3);
+    expect(msg[0]).to.closeTo(1.1, 1e-5);
+    expect(msg[1]).to.closeTo(-2.2, 1e-5);
+    expect(msg[2]).to.closeTo(3.3, 1e-5);
+  });
+});

test/karma.conf.js

@@ -12,6 +12,8 @@ module.exports = function(config) {
     // List of files / patterns to load in the browser
     files: [
       '../node_modules/eventemitter2/lib/eventemitter2.js',
+      '../node_modules/cbor-js/cbor.js',
+      '../src/util/cborTypedArrayTags.js',
       '../build/roslib.js',
       './require-shim.js',
       '*.test.js'

test/require-shim.js

@@ -1,7 +1,9 @@
 window.require = function require(path) {
 	switch (path) {
 		case 'eventemitter2': return EventEmitter2;
-		case 'xmldom': return {DOMParser: DOMParser}
+		case 'xmldom': return {DOMParser: DOMParser};
+		case 'cbor-js': return CBOR;
+		case '../src/util/cborTypedArrayTags.js': return cborTypedArrayTagger;
 	}
 	var lastIdx = path.lastIndexOf('/'),
 		path = lastIdx >= 0 ? path.slice(lastIdx + 1) : path;