1/*
2 * Copyright (c) 2012, 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.internal.util.xml.impl;
27
28import java.io.Reader;
29import java.io.InputStream;
30import java.io.IOException;
31
32/**
33 * UTF-16 encoded stream reader.
34 */
35public class ReaderUTF16 extends Reader {
36
37    private InputStream is;
38    private char bo;
39
40    /**
41     * Constructor.
42     *
43     * Byte order argument can be: 'l' for little-endian or 'b' for big-endian.
44     *
45     * @param is A byte input stream.
46     * @param bo A byte order in the input stream.
47     */
48    public ReaderUTF16(InputStream is, char bo) {
49        switch (bo) {
50            case 'l':
51                break;
52
53            case 'b':
54                break;
55
56            default:
57                throw new IllegalArgumentException("");
58        }
59        this.bo = bo;
60        this.is = is;
61    }
62
63    /**
64     * Reads characters into a portion of an array.
65     *
66     * @param cbuf Destination buffer.
67     * @param off Offset at which to start storing characters.
68     * @param len Maximum number of characters to read.
69     * @exception IOException If any IO errors occur.
70     */
71    public int read(char[] cbuf, int off, int len) throws IOException {
72        int num = 0;
73        int val;
74        if (bo == 'b') {
75            while (num < len) {
76                if ((val = is.read()) < 0) {
77                    return (num != 0) ? num : -1;
78                }
79                cbuf[off++] = (char) ((val << 8) | (is.read() & 0xff));
80                num++;
81            }
82        } else {
83            while (num < len) {
84                if ((val = is.read()) < 0) {
85                    return (num != 0) ? num : -1;
86                }
87                cbuf[off++] = (char) ((is.read() << 8) | (val & 0xff));
88                num++;
89            }
90        }
91        return num;
92    }
93
94    /**
95     * Reads a single character.
96     *
97     * @return The character read, as an integer in the range 0 to 65535
98     *  (0x0000-0xffff), or -1 if the end of the stream has been reached.
99     * @exception IOException If any IO errors occur.
100     */
101    public int read() throws IOException {
102        int val;
103        if ((val = is.read()) < 0) {
104            return -1;
105        }
106        if (bo == 'b') {
107            val = (char) ((val << 8) | (is.read() & 0xff));
108        } else {
109            val = (char) ((is.read() << 8) | (val & 0xff));
110        }
111        return val;
112    }
113
114    /**
115     * Closes the stream.
116     *
117     * @exception IOException If any IO errors occur.
118     */
119    public void close() throws IOException {
120        is.close();
121    }
122}
123