1/*
2 * Copyright (C) 2014 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. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#ifndef SegregatedFreeList_h
27#define SegregatedFreeList_h
28
29#include "Range.h"
30#include "Vector.h"
31#include <array>
32
33namespace bmalloc {
34
35class SegregatedFreeList {
36public:
37    SegregatedFreeList();
38
39    void insert(const Range&);
40
41    // Returns a reasonable fit for the provided size, or Range() if no fit
42    // is found. May return Range() spuriously if searching takes too long.
43    // Incrementally removes stale items from the free list while searching.
44    // Does not eagerly remove the returned range from the free list.
45    Range take(size_t);
46
47    // Returns an unreasonable fit for the provided size, or Range() if no fit
48    // is found. Never returns Range() spuriously.
49    // Incrementally removes stale items from the free list while searching.
50    // Eagerly removes the returned range from the free list.
51    Range takeGreedy(size_t);
52
53private:
54    typedef Vector<Range> List;
55
56    List& select(size_t);
57
58    Range take(List&, size_t);
59    Range takeGreedy(List&, size_t);
60
61    std::array<List, 19> m_lists;
62};
63
64} // namespace bmalloc
65
66#endif // SegregatedFreeList_h
67