fix(browser): fix decoding for strings with surrogate pairs (#13)

Author: darrachequesne

browser/decode.js

@@ -14,7 +14,7 @@ function Decoder(buffer) {
 }
 
 function utf8Read(view, offset, length) {
-  var string = '';
+  var string = '', chr = 0;
   for (var i = offset, end = offset + length; i < end; i++) {
     var byte = view.getUint8(i);
     if ((byte & 0x80) === 0x00) {
@@ -37,12 +37,16 @@ function utf8Read(view, offset, length) {
       continue;
     }
     if ((byte & 0xf8) === 0xf0) {
-      string += String.fromCharCode(
-        ((byte & 0x07) << 18) |
+      chr = ((byte & 0x07) << 18) |
         ((view.getUint8(++i) & 0x3f) << 12) |
         ((view.getUint8(++i) & 0x3f) << 6) |
-        ((view.getUint8(++i) & 0x3f) << 0)
-      );
+        ((view.getUint8(++i) & 0x3f) << 0);
+      if (chr >= 0x010000) { // surrogate pair
+        chr -= 0x010000;
+        string += String.fromCharCode((chr >>> 10) + 0xD800, (chr & 0x3FF) + 0xDC00);
+      } else {
+        string += String.fromCharCode(chr);
+      }
       continue;
     }
     throw new Error('Invalid byte ' + byte.toString(16));

test/browser.js

@@ -0,0 +1,76 @@
+'use strict';
+
+var notepack = {
+  encode: require('../browser/encode'),
+  decode: require('../browser/decode')
+};
+
+function array(length) {
+  var arr = new Array(length);
+  for (var i = 0; i < arr.length; i++) {
+    arr[i] = 0;
+  }
+  return arr;
+}
+
+function map(length) {
+  var result = {};
+  for (var i = 0; i < length; i++) {
+    result[i + ''] = 0;
+  }
+  return result;
+}
+
+describe('notepack (browser build)', function() {
+  it('ArrayBuffer view', function() {
+    expect(notepack.decode(Uint8Array.from([ 0x93, 1, 2, 3 ]))).to.deep.equal([ 1, 2, 3 ]);
+  });
+
+  it('offset ArrayBuffer view', function() {
+    var buffer = new ArrayBuffer(14);
+    var view = new Uint8Array(buffer);
+
+    // Fill with junk before setting the encoded data
+    view.fill(0xFF);
+
+    // Put the encoded data somewhere in the middle of the buffer
+    view.set([ 0x93, 1, 2, 3 ], 4);
+
+    expect(notepack.decode(new Uint8Array(buffer, 4, 4))).to.deep.equal([ 1, 2, 3 ]);
+    expect(notepack.decode(new Uint16Array(buffer, 4, 2))).to.deep.equal([ 1, 2, 3 ]);
+  });
+
+  it('toJSON', function () {
+    var obj = {
+      a: 'b',
+      toJSON: function () {
+        return 'c';
+      }
+    };
+    expect(notepack.encode(obj)).to.deep.equal(notepack.encode('c'));
+  });
+
+  it('all formats', function () {
+    this.timeout(20000);
+    var expected = {
+      unsigned: [1, 2, 3, 4, { b: { c: [128, 256, 65536, 4294967296] } }],
+      signed: [-1, -2, -3, -4, { b: { c: [-33, -129, -32769, -2147483649] } }],
+      bin: [Uint8Array.of('1', '2', '3').buffer, Uint8Array.from('1'.repeat(256)).buffer, Uint8Array.from('2'.repeat(65536)).buffer],
+      str: ['abc', 'g'.repeat(32), 'h'.repeat(256), 'i'.repeat(65536)],
+      array: [[], array(16), array(65536)],
+      map: {},
+      nil: null,
+      bool: { 'true': true, 'false': false, both: [true, false, false, false, true] },
+      fixext: [undefined, new Date('2140-01-01T13:14:15.678Z'), undefined, new Date('2005-12-31T23:59:59.999Z')],
+      utf8: ['α', '亜', '\uD83D\uDC26'],
+      float: [1.1, 1234567891234567.5, Infinity, -Infinity, NaN]
+    };
+    expected.map['a'.repeat(32)] = { a: 'a', b: 'b', c: 'c' };
+    expected.map['b'.repeat(256)] = { a: { b: 1, c: 1, d: 1, e: { f: { g: 2, h: 2 } } } };
+    expected.map['c'.repeat(65536)] = [{ a: { b: 1, c: 1, d: 1, e: { f: [{ g: 2, h: 2 }] } } }];
+    expected.map16 = map(65535);
+    expected.map32 = map(65536);
+
+    expect(notepack.decode(notepack.encode(expected))).to.deep.equal(expected);
+  });
+});

test/test.js

@@ -1,8 +1,6 @@
 'use strict';
 
 var notepack = require('../');
-var notepackBrowser = { encode : require('../browser/encode.js'),
-                        decode : require('../browser/decode.js') };
 
 function array(length) {
   var arr = new Array(length);
@@ -310,23 +308,3 @@ describe('notepack', function () {
     expect(notepack.decode(notepack.encode(fixture))).to.deep.equal(fixture);
   });
 });
-
-describe('notepack browser', function() {
-  it('ArrayBuffer view', function() {
-    expect(notepackBrowser.decode(Uint8Array.from([ 0x93, 1, 2, 3 ]))).to.deep.equal([ 1, 2, 3 ]);
-  });
-
-  it('offset ArrayBuffer view', function() {
-    var buffer = new ArrayBuffer(14);
-    var view = new Uint8Array(buffer);
-
-    // Fill with junk before setting the encoded data
-    view.fill(0xFF);
-
-    // Put the encoded data somewhere in the middle of the buffer
-    view.set([ 0x93, 1, 2, 3 ], 4);
-
-    expect(notepackBrowser.decode(new Uint8Array(buffer, 4, 4))).to.deep.equal([ 1, 2, 3 ]);
-    expect(notepackBrowser.decode(new Uint16Array(buffer, 4, 2))).to.deep.equal([ 1, 2, 3 ]);
-  });
-});