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/*
* 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"
#include "wtf/CPU.h"
#include "wtf/CheckedArithmetic.h"
// Use this to declare and define a static local variable (static T;) so that
// it is leaked so that its destructors are not called at exit.
#ifndef DEFINE_STATIC_LOCAL
#define DEFINE_STATIC_LOCAL(type, name, arguments) \
static type& name = *new type arguments
#endif
// Use this to declare and define a static local pointer to a ref-counted object so that
// it is leaked so that the object's destructors are not called at exit.
// This macro should be used with ref-counted objects rather than DEFINE_STATIC_LOCAL macro,
// as this macro does not lead to an extra memory allocation.
#ifndef DEFINE_STATIC_REF
#define DEFINE_STATIC_REF(type, name, arguments) \
static type* name = PassRefPtr<type>(arguments).leakRef();
#endif
// Use this macro to declare and define a debug-only global variable that may have a
// non-trivial constructor and destructor. When building with clang, this will suppress
// warnings about global constructors and exit-time destructors.
#ifndef NDEBUG
#if COMPILER(CLANG)
#define DEFINE_DEBUG_ONLY_GLOBAL(type, name, arguments) \
_Pragma("clang diagnostic push") \
_Pragma("clang diagnostic ignored \"-Wglobal-constructors\"") \
_Pragma("clang diagnostic ignored \"-Wexit-time-destructors\"") \
static type name arguments; \
_Pragma("clang diagnostic pop")
#else
#define DEFINE_DEBUG_ONLY_GLOBAL(type, name, arguments) \
static type name arguments;
#endif // COMPILER(CLANG)
#else
#define DEFINE_DEBUG_ONLY_GLOBAL(type, name, arguments)
#endif // NDEBUG
/*
* The reinterpret_cast<Type1*>([pointer to Type2]) expressions - where
* sizeof(Type1) > sizeof(Type2) - cause the following warning on ARM with GCC:
* increases required alignment of target type.
*
* An implicit or an extra static_cast<void*> bypasses the warning.
* For more info see the following bugzilla entries:
* - https://bugs.webkit.org/show_bug.cgi?id=38045
* - http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43976
*/
#if CPU(ARM) && COMPILER(GCC)
template<typename Type>
bool isPointerTypeAlignmentOkay(Type* ptr)
{
return !(reinterpret_cast<intptr_t>(ptr) % __alignof__(Type));
}
template<typename TypePtr>
TypePtr reinterpret_cast_ptr(void* ptr)
{
ASSERT(isPointerTypeAlignmentOkay(reinterpret_cast<TypePtr>(ptr)));
return reinterpret_cast<TypePtr>(ptr);
}
template<typename TypePtr>
TypePtr reinterpret_cast_ptr(const void* ptr)
{
ASSERT(isPointerTypeAlignmentOkay(reinterpret_cast<TypePtr>(ptr)));
return reinterpret_cast<TypePtr>(ptr);
}
#else
template<typename Type>
bool isPointerTypeAlignmentOkay(Type*)
{
return true;
}
#define reinterpret_cast_ptr reinterpret_cast
#endif
namespace WTF {
/*
* C++'s idea of a reinterpret_cast lacks sufficient cojones.
*/
template<typename TO, typename FROM>
inline TO bitwise_cast(FROM from)
{
static_assert(sizeof(TO) == sizeof(FROM), "WTF::bitwise_cast sizeof casted types should be equal");
union {
FROM from;
TO to;
} u;
u.from = from;
return u.to;
}
template<typename To, typename From>
inline To safeCast(From value)
{
ASSERT(isInBounds<To>(value));
return static_cast<To>(value);
}
// Macro that returns a compile time constant with the length of an array, but gives an error if passed a non-array.
template<typename T, size_t Size> char (&ArrayLengthHelperFunction(T (&)[Size]))[Size];
// GCC needs some help to deduce a 0 length array.
#if COMPILER(GCC)
template<typename T> char (&ArrayLengthHelperFunction(T (&)[0]))[0];
#endif
#define WTF_ARRAY_LENGTH(array) sizeof(::WTF::ArrayLengthHelperFunction(array))
} // namespace WTF
// This version of placement new omits a 0 check.
enum NotNullTag { NotNull };
inline void* operator new(size_t, NotNullTag, void* location)
{
ASSERT(location);
return location;
}
using WTF::bitwise_cast;
using WTF::safeCast;
#endif // WTF_StdLibExtras_h
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