1 | /* |
2 | * Copyright (C) 2008 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 WTF_StdLibExtras_h |
27 | #define |
28 | |
29 | #include <wtf/Platform.h> |
30 | #include <wtf/Assertions.h> |
31 | |
32 | // Use these to declare and define a static local variable (static T;) so that |
33 | // it is leaked so that its destructors are not called at exit. Using this |
34 | // macro also allows workarounds a compiler bug present in Apple's version of GCC 4.0.1. |
35 | #ifndef DEFINE_STATIC_LOCAL |
36 | #if COMPILER(GCC) && defined(__APPLE_CC__) && __GNUC__ == 4 && __GNUC_MINOR__ == 0 && __GNUC_PATCHLEVEL__ == 1 |
37 | #define DEFINE_STATIC_LOCAL(type, name, arguments) \ |
38 | static type* name##Ptr = new type arguments; \ |
39 | type& name = *name##Ptr |
40 | #else |
41 | #define DEFINE_STATIC_LOCAL(type, name, arguments) \ |
42 | static type& name = *new type arguments |
43 | #endif |
44 | #endif |
45 | |
46 | // OBJECT_OFFSETOF: Like the C++ offsetof macro, but you can use it with classes. |
47 | // The magic number 0x4000 is insignificant. We use it to avoid using NULL, since |
48 | // NULL can cause compiler problems, especially in cases of multiple inheritance. |
49 | #define OBJECT_OFFSETOF(class, field) (reinterpret_cast<std::ptrdiff_t>(&(reinterpret_cast<class*>(0x4000)->field)) - 0x4000) |
50 | |
51 | // STRINGIZE: Can convert any value to quoted string, even expandable macros |
52 | #define STRINGIZE(exp) #exp |
53 | #define STRINGIZE_VALUE_OF(exp) STRINGIZE(exp) |
54 | |
55 | namespace WTF { |
56 | |
57 | /* |
58 | * C++'s idea of a reinterpret_cast lacks sufficient cojones. |
59 | */ |
60 | template<typename TO, typename FROM> |
61 | TO bitwise_cast(FROM from) |
62 | { |
63 | COMPILE_ASSERT(sizeof(TO) == sizeof(FROM), WTF_bitwise_cast_sizeof_casted_types_is_equal); |
64 | union { |
65 | FROM from; |
66 | TO to; |
67 | } u; |
68 | u.from = from; |
69 | return u.to; |
70 | } |
71 | |
72 | // Returns a count of the number of bits set in 'bits'. |
73 | inline size_t bitCount(unsigned bits) |
74 | { |
75 | bits = bits - ((bits >> 1) & 0x55555555); |
76 | bits = (bits & 0x33333333) + ((bits >> 2) & 0x33333333); |
77 | return (((bits + (bits >> 4)) & 0xF0F0F0F) * 0x1010101) >> 24; |
78 | } |
79 | |
80 | } // namespace WTF |
81 | |
82 | #endif |
83 | |