/*

 * 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