StringIterator.java revision 1626:d99fa86747ee 
1/*
2 * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.  Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26package jdk.nashorn.internal.objects;
27
28import jdk.nashorn.internal.objects.annotations.Function;
29import jdk.nashorn.internal.objects.annotations.ScriptClass;
30import jdk.nashorn.internal.runtime.PropertyMap;
31import jdk.nashorn.internal.runtime.ScriptRuntime;
32import jdk.nashorn.internal.runtime.Undefined;
33
34import static jdk.nashorn.internal.runtime.ECMAErrors.typeError;
35
36/**
37 * ECMA6 21.1.5 String Iterator Objects
38 */
39@ScriptClass("StringIterator")
40public class StringIterator extends AbstractIterator {
41
42    // initialized by nasgen
43    private static PropertyMap $nasgenmap$;
44
45    private String iteratedString;
46    private int nextIndex = 0;
47    private final Global global;
48
49    StringIterator(final String iteratedString, final Global global) {
50        super(global.getStringIteratorPrototype(), $nasgenmap$);
51        this.iteratedString = iteratedString;
52        this.global = global;
53    }
54
55    /**
56     * ES6 21.1.5.2.1 %StringIteratorPrototype%.next()
57     *
58     * @param self the self reference
59     * @param arg the argument
60     * @return the next result
61     */
62    @Function
63    public static Object next(final Object self, final Object arg) {
64        if (!(self instanceof StringIterator)) {
65            throw typeError("not.a.string.iterator", ScriptRuntime.safeToString(self));
66        }
67        return ((StringIterator)self).next(arg);
68    }
69
70    @Override
71    public String getClassName() {
72        return "String Iterator";
73    }
74
75    @Override
76    protected IteratorResult next(final Object arg) {
77        final int index = nextIndex;
78        final String string = iteratedString;
79
80        if (string == null || index >= string.length()) {
81            // ES6 21.1.5.2.1 step 8
82            iteratedString = null;
83            return makeResult(Undefined.getUndefined(), Boolean.TRUE, global);
84        }
85
86        final char first = string.charAt(index);
87        if (first >= 0xd800 && first <= 0xdbff && index < string.length() - 1) {
88            final char second = string.charAt(index + 1);
89            if (second >= 0xdc00 && second <= 0xdfff) {
90                nextIndex += 2;
91                return makeResult(String.valueOf(new char[] {first, second}), Boolean.FALSE, global);
92            }
93        }
94
95        nextIndex++;
96        return makeResult(String.valueOf(first), Boolean.FALSE, global);
97    }
98}
99