1/*
2 * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25#ifndef SHARE_VM_UTILITIES_CHUNKED_LIST_HPP
26#define SHARE_VM_UTILITIES_CHUNKED_LIST_HPP
27
28#include "memory/allocation.hpp"
29#include "utilities/debug.hpp"
30
31template <class T, MEMFLAGS F> class ChunkedList : public CHeapObj<F> {
32  template <class U> friend class TestChunkedList;
33
34  static const size_t BufferSize = 64;
35
36  T  _values[BufferSize];
37  T* _top;
38
39  ChunkedList<T, F>* _next_used;
40  ChunkedList<T, F>* _next_free;
41
42  T const * end() const {
43    return &_values[BufferSize];
44  }
45
46 public:
47  ChunkedList<T, F>() : _top(_values), _next_used(NULL), _next_free(NULL) {}
48
49  bool is_full() const {
50    return _top == end();
51  }
52
53  void clear() {
54    _top = _values;
55    // Don't clear the next pointers since that would interfere
56    // with other threads trying to iterate through the lists.
57  }
58
59  void push(T m) {
60    assert(!is_full(), "Buffer is full");
61    *_top = m;
62    _top++;
63  }
64
65  void set_next_used(ChunkedList<T, F>* buffer) { _next_used = buffer; }
66  void set_next_free(ChunkedList<T, F>* buffer) { _next_free = buffer; }
67
68  ChunkedList<T, F>* next_used() const          { return _next_used; }
69  ChunkedList<T, F>* next_free() const          { return _next_free; }
70
71  size_t size() const {
72    return pointer_delta(_top, _values, sizeof(T));
73  }
74
75  T at(size_t i) {
76    assert(i < size(), "IOOBE i: " SIZE_FORMAT " size(): " SIZE_FORMAT, i, size());
77    return _values[i];
78  }
79};
80
81#endif // SHARE_VM_UTILITIES_CHUNKED_LIST_HPP
82