1/*
2 * Copyright (C) 2010 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package libcore.util;
18
19/**
20 * Various special-case charset conversions (for performance).
21 *
22 * @hide internal use only
23 */
24public final class CharsetUtils {
25    /**
26     * Returns a new byte array containing the bytes corresponding to the characters in the given
27     * string, encoded in US-ASCII. Unrepresentable characters are replaced by (byte) '?'.
28     */
29    public static native byte[] toAsciiBytes(String s, int offset, int length);
30
31    /**
32     * Returns a new byte array containing the bytes corresponding to the characters in the given
33     * string, encoded in ISO-8859-1. Unrepresentable characters are replaced by (byte) '?'.
34     */
35    public static native byte[] toIsoLatin1Bytes(String s, int offset, int length);
36
37    /**
38     * Returns a new byte array containing the bytes corresponding to the characters in the given
39     * string, encoded in UTF-8. All characters are representable in UTF-8.
40     */
41    public static native byte[] toUtf8Bytes(String s, int offset, int length);
42
43    /**
44     * Returns a new byte array containing the bytes corresponding to the characters in the given
45     * string, encoded in UTF-16BE. All characters are representable in UTF-16BE.
46     */
47    public static byte[] toBigEndianUtf16Bytes(String s, int offset, int length) {
48        byte[] result = new byte[length * 2];
49        int end = offset + length;
50        int resultIndex = 0;
51        for (int i = offset; i < end; ++i) {
52            char ch = s.charAt(i);
53            result[resultIndex++] = (byte) (ch >> 8);
54            result[resultIndex++] = (byte) ch;
55        }
56        return result;
57    }
58
59    /**
60     * Decodes the given US-ASCII bytes into the given char[]. Equivalent to but faster than:
61     *
62     * for (int i = 0; i < count; ++i) {
63     *     char ch = (char) (data[start++] & 0xff);
64     *     value[i] = (ch <= 0x7f) ? ch : REPLACEMENT_CHAR;
65     * }
66     */
67    public static native void asciiBytesToChars(byte[] bytes, int offset, int length, char[] chars);
68
69    /**
70     * Decodes the given ISO-8859-1 bytes into the given char[]. Equivalent to but faster than:
71     *
72     * for (int i = 0; i < count; ++i) {
73     *     value[i] = (char) (data[start++] & 0xff);
74     * }
75     */
76    public static native void isoLatin1BytesToChars(byte[] bytes, int offset, int length, char[] chars);
77
78    private CharsetUtils() {
79    }
80}
81