1// Copyright 2014 the V8 project authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5'use strict';
6
7
8// This file relies on the fact that the following declaration has been made
9// in runtime.js:
10// var $String = global.String;
11
12
13var stringIteratorIteratedStringSymbol =
14    GLOBAL_PRIVATE("StringIterator#iteratedString");
15var stringIteratorNextIndexSymbol = GLOBAL_PRIVATE("StringIterator#next");
16
17
18function StringIterator() {}
19
20
21// 21.1.5.1 CreateStringIterator Abstract Operation
22function CreateStringIterator(string) {
23  var s = TO_STRING_INLINE(string);
24  var iterator = new StringIterator;
25  SET_PRIVATE(iterator, stringIteratorIteratedStringSymbol, s);
26  SET_PRIVATE(iterator, stringIteratorNextIndexSymbol, 0);
27  return iterator;
28}
29
30
31// 21.1.5.2.2 %StringIteratorPrototype%[@@iterator]
32function StringIteratorIterator() {
33  return this;
34}
35
36
37// 21.1.5.2.1 %StringIteratorPrototype%.next( )
38function StringIteratorNext() {
39  var iterator = ToObject(this);
40
41  if (!HAS_DEFINED_PRIVATE(iterator, stringIteratorNextIndexSymbol)) {
42    throw MakeTypeError('incompatible_method_receiver',
43                        ['String Iterator.prototype.next']);
44  }
45
46  var s = GET_PRIVATE(iterator, stringIteratorIteratedStringSymbol);
47  if (IS_UNDEFINED(s)) {
48    return CreateIteratorResultObject(UNDEFINED, true);
49  }
50
51  var position = GET_PRIVATE(iterator, stringIteratorNextIndexSymbol);
52  var length = TO_UINT32(s.length);
53
54  if (position >= length) {
55    SET_PRIVATE(iterator, stringIteratorIteratedStringSymbol,
56                UNDEFINED);
57    return CreateIteratorResultObject(UNDEFINED, true);
58  }
59
60  var first = %_StringCharCodeAt(s, position);
61  var resultString = %_StringCharFromCode(first);
62  position++;
63
64  if (first >= 0xD800 && first <= 0xDBFF && position < length) {
65    var second = %_StringCharCodeAt(s, position);
66    if (second >= 0xDC00 && second <= 0xDFFF) {
67      resultString += %_StringCharFromCode(second);
68      position++;
69    }
70  }
71
72  SET_PRIVATE(iterator, stringIteratorNextIndexSymbol, position);
73
74  return CreateIteratorResultObject(resultString, false);
75}
76
77
78function SetUpStringIterator() {
79  %CheckIsBootstrapping();
80
81  %FunctionSetPrototype(StringIterator, new $Object());
82  %FunctionSetInstanceClassName(StringIterator, 'String Iterator');
83
84  InstallFunctions(StringIterator.prototype, DONT_ENUM, $Array(
85    'next', StringIteratorNext
86  ));
87  %FunctionSetName(StringIteratorIterator, '[Symbol.iterator]');
88  %AddNamedProperty(StringIterator.prototype, symbolIterator,
89                    StringIteratorIterator, DONT_ENUM);
90}
91SetUpStringIterator();
92
93
94// 21.1.3.27 String.prototype [ @@iterator ]( )
95function StringPrototypeIterator() {
96  return CreateStringIterator(this);
97}
98
99
100function ExtendStringPrototypeWithIterator() {
101  %CheckIsBootstrapping();
102
103  %FunctionSetName(StringPrototypeIterator, '[Symbol.iterator]');
104  %AddNamedProperty($String.prototype, symbolIterator,
105                    StringPrototypeIterator, DONT_ENUM);
106}
107ExtendStringPrototypeWithIterator();
108