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michael@0:  *
michael@0:  * ***** BEGIN LICENSE BLOCK *****
michael@0:  * Copyright (C) 2010 Apple Inc. All rights reserved.
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michael@0:  * Redistribution and use in source and binary forms, with or without
michael@0:  * modification, are permitted provided that the following conditions
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michael@0:  * 1. Redistributions of source code must retain the above copyright
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michael@0:  * 2. Redistributions in binary form must reproduce the above copyright
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michael@0:  *    documentation and/or other materials provided with the distribution.
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michael@0:  * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
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michael@0:  * THE POSSIBILITY OF SUCH DAMAGE.
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michael@0:  * ***** END LICENSE BLOCK ***** */
michael@0: 
michael@0: #ifndef yarr_PageBlock_h
michael@0: #define yarr_PageBlock_h
michael@0: 
michael@0: #include <stddef.h>
michael@0: #include <stdint.h>
michael@0: 
michael@0: namespace WTF {
michael@0: 
michael@0: size_t pageSize();
michael@0: inline bool isPageAligned(void* address) { return !(reinterpret_cast<intptr_t>(address) & (pageSize() - 1)); }
michael@0: inline bool isPageAligned(size_t size) { return !(size & (pageSize() - 1)); }
michael@0: inline bool isPowerOfTwo(size_t size) { return !(size & (size - 1)); }
michael@0: 
michael@0: class PageBlock {
michael@0: public:
michael@0:     PageBlock();
michael@0:     PageBlock(const PageBlock&);
michael@0:     PageBlock(void*, size_t);
michael@0: 
michael@0:     void* base() const { return m_base; }
michael@0:     size_t size() const { return m_size; }
michael@0: 
michael@0:     operator bool() const { return !!m_base; }
michael@0: 
michael@0:     bool contains(void* containedBase, size_t containedSize)
michael@0:     {
michael@0:         return containedBase >= m_base
michael@0:             && (static_cast<char*>(containedBase) + containedSize) <= (static_cast<char*>(m_base) + m_size);
michael@0:     }
michael@0: 
michael@0: private:
michael@0:     void* m_base;
michael@0:     size_t m_size;
michael@0: };
michael@0: 
michael@0: inline PageBlock::PageBlock()
michael@0:     : m_base(0)
michael@0:     , m_size(0)
michael@0: {
michael@0: }
michael@0: 
michael@0: inline PageBlock::PageBlock(const PageBlock& other)
michael@0:     : m_base(other.m_base)
michael@0:     , m_size(other.m_size)
michael@0: {
michael@0: }
michael@0: 
michael@0: inline PageBlock::PageBlock(void* base, size_t size)
michael@0:     : m_base(base)
michael@0:     , m_size(size)
michael@0: {
michael@0: }
michael@0: 
michael@0: } // namespace WTF
michael@0: 
michael@0: using WTF::pageSize;
michael@0: using WTF::isPageAligned;
michael@0: using WTF::isPageAligned;
michael@0: using WTF::isPowerOfTwo;
michael@0: 
michael@0: #endif /* yarr_PageBlock_h */