1 /*
2 * Copyright (c) 1997, 2023, 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.
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23 */
24
25 #ifndef SHARE_LIBADT_VECTSET_HPP
26 #define SHARE_LIBADT_VECTSET_HPP
27
28 #include "memory/allocation.hpp"
29 #include "utilities/copy.hpp"
30
31 // Vector Sets
32
33 // These sets can grow or shrink, based on the initial size and the largest
34 // element currently in them.
35
36 //------------------------------VectorSet--------------------------------------
37 class VectorSet : public AnyObj {
38 private:
39
40 static const uint word_bits = 5;
41 static const uint bit_mask = 31;
42
43 // Used 32-bit words
44 uint _size;
45 uint32_t* _data;
46 // Allocated words
47 uint _data_size;
48 Arena* _set_arena;
49
50 void init(Arena* arena);
51 // Grow vector to required word capacity
52 void grow(uint new_word_capacity);
53 public:
54 VectorSet();
55 VectorSet(Arena* arena);
56 ~VectorSet() {}
57
58 NONCOPYABLE(VectorSet);
59 VectorSet& operator=(VectorSet&&) = delete;
60 // Allow move constructor for && (eg. capture return of function)
61 VectorSet(VectorSet&&) = default;
62
63 void insert(uint elem);
64 bool is_empty() const;
65 void reset() {
66 _size = 0;
67 }
68 void clear() {
69 reset();
70 }
71
72 // Fast inlined "test and set". Replaces the idiom:
73 // if (visited.test(idx)) return;
74 // visited.set(idx);
75 // With:
76 // if (visited.test_set(idx)) return;
77 //
78 bool test_set(uint elem) {
79 uint32_t word = elem >> word_bits;
80 if (word >= _size) {
81 // Then grow
82 grow(word);
83 }
84 uint32_t mask = 1U << (elem & bit_mask);
85 uint32_t data = _data[word];
86 _data[word] = data | mask;
87 return (data & mask) != 0;
88 }
89
90 // Fast inlined test
91 bool test(uint elem) const {
92 uint32_t word = elem >> word_bits;
93 if (word >= _size) {
94 return false;
95 }
96 uint32_t mask = 1U << (elem & bit_mask);
97 return (_data[word] & mask) != 0;
98 }
99
100 void remove(uint elem) {
101 uint32_t word = elem >> word_bits;
102 if (word >= _size) {
103 return;
104 }
105 uint32_t mask = 1U << (elem & bit_mask);
106 _data[word] &= ~mask; // Clear bit
107 }
108
109 // Fast inlined set
110 void set(uint elem) {
111 uint32_t word = elem >> word_bits;
112 if (word >= _size) {
113 grow(word);
114 }
115 uint32_t mask = 1U << (elem & bit_mask);
116 _data[word] |= mask;
117 }
118 };
119
120 #endif // SHARE_LIBADT_VECTSET_HPP