1/*
2 * Copyright (C) 2013 Apple Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 *    notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 *    notice, this list of conditions and the following disclaimer in the
11 *    documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#ifndef FlipBytes_h
27#define FlipBytes_h
28
29namespace WTF {
30
31inline bool needToFlipBytesIfLittleEndian(bool littleEndian)
32{
33#if CPU(BIG_ENDIAN)
34    return littleEndian;
35#else
36    return !littleEndian;
37#endif
38}
39
40inline uint16_t flipBytes(uint16_t value)
41{
42    return ((value & 0x00ff) << 8)
43        | ((value & 0xff00) >> 8);
44}
45
46inline uint32_t flipBytes(uint32_t value)
47{
48    return ((value & 0x000000ff) << 24)
49        | ((value & 0x0000ff00) << 8)
50        | ((value & 0x00ff0000) >> 8)
51        | ((value & 0xff000000) >> 24);
52}
53
54inline uint64_t flipBytes(uint64_t value)
55{
56    return ((value & 0x00000000000000ffull) << 56)
57        | ((value & 0x000000000000ff00ull) << 40)
58        | ((value & 0x0000000000ff0000ull) << 24)
59        | ((value & 0x00000000ff000000ull) << 8)
60        | ((value & 0x000000ff00000000ull) >> 8)
61        | ((value & 0x0000ff0000000000ull) >> 24)
62        | ((value & 0x00ff000000000000ull) >> 40)
63        | ((value & 0xff00000000000000ull) >> 56);
64}
65
66template<typename T>
67inline T flipBytes(T value)
68{
69    if (sizeof(value) == 1)
70        return value;
71    if (sizeof(value) == 2) {
72        union {
73            T original;
74            uint16_t word;
75        } u;
76        u.original = value;
77        u.word = flipBytes(u.word);
78        return u.original;
79    }
80    if (sizeof(value) == 4) {
81        union {
82            T original;
83            uint32_t word;
84        } u;
85        u.original = value;
86        u.word = flipBytes(u.word);
87        return u.original;
88    }
89    if (sizeof(value) == 8) {
90        union {
91            T original;
92            uint64_t word;
93        } u;
94        u.original = value;
95        u.word = flipBytes(u.word);
96        return u.original;
97    }
98    RELEASE_ASSERT_NOT_REACHED();
99    return T();
100}
101
102template<typename T>
103inline T flipBytesIfLittleEndian(T value, bool littleEndian)
104{
105    if (needToFlipBytesIfLittleEndian(littleEndian))
106        return flipBytes(value);
107    return value;
108}
109
110} // namespace WTF
111
112using WTF::needToFlipBytesIfLittleEndian;
113using WTF::flipBytes;
114using WTF::flipBytesIfLittleEndian;
115
116#endif // FlipBytes_h
117
118