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      1 /*
      2  * Copyright (C) 2010 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 #include "config.h"
     32 
     33 #include "wtf/Assertions.h"
     34 #include "wtf/OwnPtr.h"
     35 #include "wtf/PassRefPtr.h"
     36 #include "wtf/RefCounted.h"
     37 #include "wtf/RefPtr.h"
     38 #include "wtf/ThreadRestrictionVerifier.h"
     39 #include "wtf/Vector.h"
     40 #include "wtf/text/AtomicString.h"
     41 #include "wtf/text/WTFString.h"
     42 
     43 namespace WTF {
     44 
     45 #if !defined(NDEBUG) || SECURITY_ASSERT_ENABLED
     46 // The debug/assertion version may get bigger.
     47 struct SameSizeAsRefCounted {
     48     int a;
     49 #if SECURITY_ASSERT_ENABLED
     50     bool b;
     51 #endif
     52 #if !defined(NDEBUG)
     53     bool c;
     54     ThreadRestrictionVerifier d;
     55 #endif
     56 };
     57 #else
     58 struct SameSizeAsRefCounted {
     59     int a;
     60     // Don't add anything here because this should stay small.
     61 };
     62 #endif
     63 template<typename T, unsigned inlineCapacity = 0>
     64 struct SameSizeAsVectorWithInlineCapacity;
     65 
     66 template<typename T>
     67 struct SameSizeAsVectorWithInlineCapacity<T, 0> {
     68     void* bufferPointer;
     69     unsigned capacity;
     70     unsigned size;
     71 };
     72 
     73 template<typename T, unsigned inlineCapacity>
     74 struct SameSizeAsVectorWithInlineCapacity {
     75     SameSizeAsVectorWithInlineCapacity<T, 0> baseCapacity;
     76     AlignedBuffer<inlineCapacity * sizeof(T), WTF_ALIGN_OF(T)> inlineBuffer;
     77 };
     78 
     79 COMPILE_ASSERT(sizeof(OwnPtr<int>) == sizeof(int*), OwnPtr_should_stay_small);
     80 COMPILE_ASSERT(sizeof(PassRefPtr<RefCounted<int> >) == sizeof(int*), PassRefPtr_should_stay_small);
     81 COMPILE_ASSERT(sizeof(RefCounted<int>) == sizeof(SameSizeAsRefCounted), RefCounted_should_stay_small);
     82 COMPILE_ASSERT(sizeof(RefPtr<RefCounted<int> >) == sizeof(int*), RefPtr_should_stay_small);
     83 COMPILE_ASSERT(sizeof(String) == sizeof(int*), String_should_stay_small);
     84 COMPILE_ASSERT(sizeof(AtomicString) == sizeof(String), AtomicString_should_stay_small);
     85 COMPILE_ASSERT(sizeof(Vector<int>) == sizeof(SameSizeAsVectorWithInlineCapacity<int>), Vector_should_stay_small);
     86 COMPILE_ASSERT(sizeof(Vector<int, 1>) == sizeof(SameSizeAsVectorWithInlineCapacity<int, 1>), Vector_should_stay_small);
     87 COMPILE_ASSERT(sizeof(Vector<int, 2>) == sizeof(SameSizeAsVectorWithInlineCapacity<int, 2>), Vector_should_stay_small);
     88 COMPILE_ASSERT(sizeof(Vector<int, 3>) == sizeof(SameSizeAsVectorWithInlineCapacity<int, 3>), Vector_should_stay_small);
     89 }
     90