1/*
2 * Copyright (C) 2015 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#pragma once
27
28#include <wtf/FastMalloc.h>
29#include <wtf/Lock.h>
30#include <wtf/Noncopyable.h>
31
32namespace WTF {
33
34template<typename VectorType>
35class ParallelVectorIterator {
36 WTF_MAKE_NONCOPYABLE(ParallelVectorIterator);
37 WTF_MAKE_FAST_ALLOCATED;
38public:
39 ParallelVectorIterator(VectorType& vector, size_t shardSize)
40 : m_vector(vector)
41 , m_shardSize(shardSize)
42 {
43 }
44
45 template<typename Functor>
46 ALWAYS_INLINE void iterate(const Functor& functor)
47 {
48 for (;;) {
49 size_t begin;
50 size_t end;
51 {
52 LockHolder locker(m_lock);
53 begin = m_next;
54 if (begin == m_vector.size())
55 return;
56 if (m_vector.size() - begin < m_shardSize)
57 end = m_vector.size();
58 else
59 end = begin + m_shardSize;
60 RELEASE_ASSERT(end <= m_vector.size());
61 RELEASE_ASSERT(begin < end);
62 m_next = end;
63 }
64
65 for (size_t i = begin; i < end; ++i)
66 functor(m_vector[i]);
67 }
68 }
69private:
70 VectorType& m_vector;
71 Lock m_lock;
72 size_t m_shardSize;
73 size_t m_next { 0 };
74};
75
76} // namespace WTF
77
78using WTF::ParallelVectorIterator;
79