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/*
* Copyright (C) 2010 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. AND ITS CONTRIBUTORS ``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 ITS 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 PageBlock_h
#define PageBlock_h
namespace WTF {
WTF_EXPORT_PRIVATE size_t pageSize();
WTF_EXPORT_PRIVATE size_t pageMask();
inline bool isPageAligned(void* address) { return !(reinterpret_cast<intptr_t>(address) & (pageSize() - 1)); }
inline bool isPageAligned(size_t size) { return !(size & (pageSize() - 1)); }
inline bool isPowerOfTwo(size_t size) { return !(size & (size - 1)); }
class PageBlock {
public:
PageBlock();
PageBlock(void*, size_t, bool hasGuardPages);
void* realBase() const { return m_realBase; }
void* base() const { return m_base; }
size_t size() const
{
return m_size - 2 * (static_cast<char *>(m_base) - static_cast<char *>(m_realBase));
}
size_t realSize() const { return m_size; }
operator bool() const { return !!m_realBase; }
bool contains(void* containedBase, size_t containedSize)
{
return containedBase >= m_base
&& (static_cast<char*>(containedBase) + containedSize) <= (static_cast<char*>(m_base) + m_size);
}
private:
void* m_realBase;
void* m_base;
size_t m_size;
};
inline PageBlock::PageBlock()
: m_realBase(0)
, m_base(0)
, m_size(0)
{
}
inline PageBlock::PageBlock(void* base, size_t size, bool hasGuardPages)
: m_realBase(base)
, m_base(static_cast<char*>(base) + ((base && hasGuardPages) ? pageSize() : 0))
, m_size(size)
{
}
} // namespace WTF
using WTF::pageSize;
using WTF::isPageAligned;
using WTF::isPageAligned;
using WTF::isPowerOfTwo;
#endif // PageBlock_h
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