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1 /*
2  * Copyright (C) 2009 Google 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 are
6  * met:
7  *
8  *     * Redistributions of source code must retain the above copyright
9  * notice, this list of conditions and the following disclaimer.
10  *     * Redistributions in binary form must reproduce the above
11  * copyright notice, this list of conditions and the following disclaimer
12  * in the documentation and/or other materials provided with the
13  * distribution.
14  *     * Neither the name of Google Inc. nor the names of its
15  * contributors may be used to endorse or promote products derived from
16  * this software without specific prior written permission.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
24  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29  */
30 
31 #ifndef PtrAndFlags_h
32 #define PtrAndFlags_h
33 
34 #include <wtf/Assertions.h>
35 
36 namespace WTF {
37     template<class T, typename FlagEnum> class PtrAndFlags {
38     public:
PtrAndFlags()39         PtrAndFlags() : m_ptrAndFlags(0) {}
PtrAndFlags(T * ptr)40         PtrAndFlags(T* ptr) : m_ptrAndFlags(0) { set(ptr); }
41 
isFlagSet(FlagEnum flagNumber)42         bool isFlagSet(FlagEnum flagNumber) const { ASSERT(flagNumber < 2); return m_ptrAndFlags & (1 << flagNumber); }
setFlag(FlagEnum flagNumber)43         void setFlag(FlagEnum flagNumber) { ASSERT(flagNumber < 2); m_ptrAndFlags |= (1 << flagNumber);}
clearFlag(FlagEnum flagNumber)44         void clearFlag(FlagEnum flagNumber) { ASSERT(flagNumber < 2); m_ptrAndFlags &= ~(1 << flagNumber);}
get()45         T* get() const { return reinterpret_cast<T*>(m_ptrAndFlags & ~3); }
set(T * ptr)46         void set(T* ptr)
47         {
48             ASSERT(!(reinterpret_cast<intptr_t>(ptr) & 3));
49             m_ptrAndFlags = reinterpret_cast<intptr_t>(ptr) | (m_ptrAndFlags & 3);
50 #ifndef NDEBUG
51             m_leaksPtr = ptr;
52 #endif
53         }
54 
55         bool operator!() const { return !get(); }
56         T* operator->() const { return reinterpret_cast<T*>(m_ptrAndFlags & ~3); }
57 
58     private:
59         intptr_t m_ptrAndFlags;
60 #ifndef NDEBUG
61         void* m_leaksPtr; // Only used to allow tools like leaks on OSX to detect that the memory is referenced.
62 #endif
63     };
64 } // namespace WTF
65 
66 using WTF::PtrAndFlags;
67 
68 #endif // PtrAndFlags_h
69