1/*
2 * Copyright (C) 2010 Apple 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
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
14 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
15 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
17 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
18 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
19 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
20 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
21 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
22 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
23 * THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#ifndef PageBlock_h
27#define PageBlock_h
28
29namespace WTF {
30
31WTF_EXPORT_PRIVATE size_t pageSize();
32WTF_EXPORT_PRIVATE size_t pageMask();
33inline bool isPageAligned(void* address) { return !(reinterpret_cast<intptr_t>(address) & (pageSize() - 1)); }
34inline bool isPageAligned(size_t size) { return !(size & (pageSize() - 1)); }
35inline bool isPowerOfTwo(size_t size) { return !(size & (size - 1)); }
36
37class PageBlock {
38public:
39 PageBlock();
40 PageBlock(const PageBlock&);
41 PageBlock(void*, size_t, bool hasGuardPages);
42
43 void* base() const { return m_base; }
44 size_t size() const { return m_size; }
45
46 operator bool() const { return !!m_realBase; }
47
48 bool contains(void* containedBase, size_t containedSize)
49 {
50 return containedBase >= m_base
51 && (static_cast<char*>(containedBase) + containedSize) <= (static_cast<char*>(m_base) + m_size);
52 }
53
54private:
55 void* m_realBase;
56 void* m_base;
57 size_t m_size;
58};
59
60inline PageBlock::PageBlock()
61 : m_realBase(0)
62 , m_base(0)
63 , m_size(0)
64{
65}
66
67inline PageBlock::PageBlock(const PageBlock& other)
68 : m_realBase(other.m_realBase)
69 , m_base(other.m_base)
70 , m_size(other.m_size)
71{
72}
73
74inline PageBlock::PageBlock(void* base, size_t size, bool hasGuardPages)
75 : m_realBase(base)
76 , m_base(static_cast<char*>(base) + ((base && hasGuardPages) ? pageSize() : 0))
77 , m_size(size)
78{
79}
80
81} // namespace WTF
82
83using WTF::pageSize;
84using WTF::isPageAligned;
85using WTF::isPowerOfTwo;
86
87#endif // PageBlock_h
88