/* | |
* Copyright (C) 2008 Apple Inc. All Rights Reserved. | |
* | |
* Redistribution and use in source and binary forms, with or without | |
* modification, are permitted provided that the following conditions | |
* are met: | |
* 1. Redistributions of source code must retain the above copyright | |
* notice, this list of conditions and the following disclaimer. | |
* 2. Redistributions in binary form must reproduce the above copyright | |
* notice, this list of conditions and the following disclaimer in the | |
* documentation and/or other materials provided with the distribution. | |
* | |
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY | |
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR | |
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR | |
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, | |
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, | |
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR | |
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY | |
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE | |
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
*/ | |
#ifndef WTF_StdLibExtras_h | |
#define WTF_StdLibExtras_h | |
#include <wtf/Assertions.h> | |
// Use these to declare and define a static local variable (static T;) so that | |
// it is leaked so that its destructors are not called at exit. Using this | |
// macro also allows workarounds a compiler bug present in Apple's version of GCC 4.0.1. | |
#ifndef DEFINE_STATIC_LOCAL | |
#if COMPILER(GCC) && defined(__APPLE_CC__) && __GNUC__ == 4 && __GNUC_MINOR__ == 0 && __GNUC_PATCHLEVEL__ == 1 | |
#define DEFINE_STATIC_LOCAL(type, name, arguments) \ | |
static type* name##Ptr = new type arguments; \ | |
type& name = *name##Ptr | |
#else | |
#define DEFINE_STATIC_LOCAL(type, name, arguments) \ | |
static type& name = *new type arguments | |
#endif | |
#endif | |
// OBJECT_OFFSETOF: Like the C++ offsetof macro, but you can use it with classes. | |
// The magic number 0x4000 is insignificant. We use it to avoid using NULL, since | |
// NULL can cause compiler problems, especially in cases of multiple inheritance. | |
#define OBJECT_OFFSETOF(class, field) (reinterpret_cast<ptrdiff_t>(&(reinterpret_cast<class*>(0x4000)->field)) - 0x4000) | |
// STRINGIZE: Can convert any value to quoted string, even expandable macros | |
#define STRINGIZE(exp) #exp | |
#define STRINGIZE_VALUE_OF(exp) STRINGIZE(exp) | |
namespace WTF { | |
/* | |
* C++'s idea of a reinterpret_cast lacks sufficient cojones. | |
*/ | |
template<typename TO, typename FROM> | |
TO bitwise_cast(FROM from) | |
{ | |
COMPILE_ASSERT(sizeof(TO) == sizeof(FROM), WTF_bitwise_cast_sizeof_casted_types_is_equal); | |
union { | |
FROM from; | |
TO to; | |
} u; | |
u.from = from; | |
return u.to; | |
} | |
// Returns a count of the number of bits set in 'bits'. | |
inline size_t bitCount(unsigned bits) | |
{ | |
bits = bits - ((bits >> 1) & 0x55555555); | |
bits = (bits & 0x33333333) + ((bits >> 2) & 0x33333333); | |
return (((bits + (bits >> 4)) & 0xF0F0F0F) * 0x1010101) >> 24; | |
} | |
} // namespace WTF | |
#endif |