Move Source/WTF/wtf to Source/wtf

Source/WTF/wtf/RefCountedArray.h

-/*
- * Copyright (C) 2011 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 RefCountedArray_h
-#define RefCountedArray_h
-
-#include <wtf/FastMalloc.h>
-#include <wtf/StdLibExtras.h>
-#include <wtf/Vector.h>
-
-// This implements a reference counted array for POD** values, which is optimized for:
-// - An empty array only uses one word.
-// - A copy of the array only uses one word (i.e. assignment means aliasing).
-// - The vector can't grow beyond 2^32-1 elements.
-// - In all other regards this has similar space usage to a Vector.
-//
-// ** This could be modified to support non-POD values quite easily. It just
-//    hasn't been, so far, because there has been no need. Moreover, even now,
-//    it's used for things that aren't quite POD according to the official
-//    defintion, such as JSC::Instruction.
-
-namespace WTF {
-
-template<typename T>
-class RefCountedArray {
-public:
-    RefCountedArray()
-        : m_data(0)
-    {
-    }
-    
-    RefCountedArray(const RefCountedArray& other)
-        : m_data(other.m_data)
-    {
-        if (m_data)
-            Header::fromPayload(m_data)->refCount++;
-    }
-
-    explicit RefCountedArray(size_t size)
-    {
-        if (!size) {
-            m_data = 0;
-            return;
-        }
-
-        m_data = (static_cast<Header*>(fastMalloc(Header::size() + sizeof(T) * size)))->payload();
-        Header::fromPayload(m_data)->refCount = 1;
-        Header::fromPayload(m_data)->length = size;
-        ASSERT(Header::fromPayload(m_data)->length == size);
-        VectorTypeOperations<T>::initialize(begin(), end());
-    }
-
-    explicit RefCountedArray(const Vector<T>& other)
-    {
-        if (other.isEmpty()) {
-            m_data = 0;
-            return;
-        }
-        
-        m_data = (static_cast<Header*>(fastMalloc(Header::size() + sizeof(T) * other.size())))->payload();
-        Header::fromPayload(m_data)->refCount = 1;
-        Header::fromPayload(m_data)->length = other.size();
-        ASSERT(Header::fromPayload(m_data)->length == other.size());
-        memcpy(m_data, other.begin(), sizeof(T) * other.size());
-    }
-    
-    RefCountedArray& operator=(const RefCountedArray& other)
-    {
-        T* oldData = m_data;
-        m_data = other.m_data;
-        if (m_data)
-            Header::fromPayload(m_data)->refCount++;
-        
-        if (!oldData)
-            return *this;
-        if (--Header::fromPayload(oldData)->refCount)
-            return *this;
-        fastFree(Header::fromPayload(oldData));
-        return *this;
-    }
-    
-    ~RefCountedArray()
-    {
-        if (!m_data)
-            return;
-        if (--Header::fromPayload(m_data)->refCount)
-            return;
-        fastFree(Header::fromPayload(m_data));
-    }
-    
-    size_t size() const
-    {
-        if (!m_data)
-            return 0;
-        return Header::fromPayload(m_data)->length;
-    }
-    
-    T* data() { return m_data; }
-    T* begin() { return m_data; }
-    T* end()
-    {
-        if (!m_data)
-            return 0;
-        return m_data + Header::fromPayload(m_data)->length;
-    }
-    
-    const T* data() const { return m_data; }
-    const T* begin() const { return m_data; }
-    const T* end() const { return const_cast<RefCountedArray*>(this)->end(); }
-    
-    T& at(size_t i)
-    {
-        ASSERT_WITH_SECURITY_IMPLICATION(i < size());
-        return begin()[i];
-    }
-    
-    const T& at(size_t i) const
-    {
-        ASSERT_WITH_SECURITY_IMPLICATION(i < size());
-        return begin()[i];
-    }
-    
-    T& operator[](size_t i) { return at(i); }
-    const T& operator[](size_t i) const { return at(i); }
-    
-private:
-    struct Header {
-        unsigned refCount;
-        unsigned length;
-        
-        static size_t size()
-        {
-            return (sizeof(Header) + 7) & ~7;
-        }
-        
-        T* payload()
-        {
-            char* result = reinterpret_cast<char*>(this) + size();
-            ASSERT(!(bitwise_cast<uintptr_t>(result) & 7));
-            return reinterpret_cast_ptr<T*>(result);
-        }
-        
-        static Header* fromPayload(T* payload)
-        {
-            return reinterpret_cast_ptr<Header*>(reinterpret_cast<char*>(payload) - size());
-        }
-    };
-    
-    T* m_data;
-};
-
-} // namespace WTF
-
-using WTF::RefCountedArray;
-
-#endif // RefCountedArray_h
-