1/*
2 * Copyright (C) 2014 Square, Inc.
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 */
16package okio;
17
18import java.nio.charset.Charset;
19
20final class Util {
21  /** A cheap and type-safe constant for the UTF-8 Charset. */
22  public static final Charset UTF_8 = Charset.forName("UTF-8");
23
24  private Util() {
25  }
26
27  public static void checkOffsetAndCount(long arrayLength, long offset, long count) {
28    if ((offset | count) < 0 || offset > arrayLength || arrayLength - offset < count) {
29      throw new ArrayIndexOutOfBoundsException();
30    }
31  }
32
33  public static short reverseBytesShort(short s) {
34    int i = s & 0xffff;
35    int reversed = (i & 0xff00) >>> 8
36        |          (i & 0x00ff)  << 8;
37    return (short) reversed;
38  }
39
40  public static int reverseBytesInt(int i) {
41    return (i & 0xff000000) >>> 24
42        |  (i & 0x00ff0000) >>>  8
43        |  (i & 0x0000ff00)  <<  8
44        |  (i & 0x000000ff)  << 24;
45  }
46
47  public static long reverseBytesLong(long v) {
48    return (v & 0xff00000000000000L) >>> 56
49        |  (v & 0x00ff000000000000L) >>> 40
50        |  (v & 0x0000ff0000000000L) >>> 24
51        |  (v & 0x000000ff00000000L) >>>  8
52        |  (v & 0x00000000ff000000L)  <<  8
53        |  (v & 0x0000000000ff0000L)  << 24
54        |  (v & 0x000000000000ff00L)  << 40
55        |  (v & 0x00000000000000ffL)  << 56;
56  }
57
58  /**
59   * Throws {@code t}, even if the declared throws clause doesn't permit it.
60   * This is a terrible – but terribly convenient – hack that makes it easy to
61   * catch and rethrow exceptions after cleanup. See Java Puzzlers #43.
62   */
63  public static void sneakyRethrow(Throwable t) {
64    Util.<Error>sneakyThrow2(t);
65  }
66
67  @SuppressWarnings("unchecked")
68  private static <T extends Throwable> void sneakyThrow2(Throwable t) throws T {
69    throw (T) t;
70  }
71}
72