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 
17 package libcore.util;
18 
19 /**
20  * Various special-case charset conversions (for performance).
21  *
22  * @hide internal use only
23  */
24 public 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      */
toAsciiBytes(String s, int offset, int length)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      */
toIsoLatin1Bytes(String s, int offset, int length)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      */
toUtf8Bytes(String s, int offset, int length)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      */
toBigEndianUtf16Bytes(String s, int offset, int length)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      */
asciiBytesToChars(byte[] bytes, int offset, int length, char[] chars)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      */
isoLatin1BytesToChars(byte[] bytes, int offset, int length, char[] chars)76     public static native void isoLatin1BytesToChars(byte[] bytes, int offset, int length, char[] chars);
77 
CharsetUtils()78     private CharsetUtils() {
79     }
80 }
81