1 /*
2 * Copyright (c) 1997, 2024, 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_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 // Allocated words
46 uint _data_size;
47 uint32_t* _data;
48 Arena* _set_arena;
49 ReallocMark _nesting; // Safety checks for arena reallocation
50
51 void init(Arena* arena);
52
53 // Grow vector to required word capacity
54 void maybe_grow(uint new_word_capacity) {
55 if (new_word_capacity >= _size) {
56 grow(new_word_capacity);
57 }
58 }
59 void grow(uint new_word_capacity);
60
61 public:
62 VectorSet();
63 VectorSet(Arena* arena);
64 ~VectorSet() {}
65
66 NONCOPYABLE(VectorSet);
67 VectorSet& operator=(VectorSet&&) = delete;
68 // Allow move constructor for && (eg. capture return of function)
69 VectorSet(VectorSet&&) = default;
70
71 void insert(uint elem);
72 bool is_empty() const;
73 void reset() {
74 _size = 0;
75 }
76 void clear() {
77 reset();
78 }
79
80 // Fast inlined "test and set". Replaces the idiom:
81 // if (visited.test(idx)) return;
82 // visited.set(idx);
83 // With:
84 // if (visited.test_set(idx)) return;
85 //
86 bool test_set(uint elem) {
87 uint32_t word = elem >> word_bits;
88 maybe_grow(word);
89 uint32_t mask = 1U << (elem & bit_mask);
90 uint32_t data = _data[word];
91 _data[word] = data | mask;
92 return (data & mask) != 0;
93 }
94
95 // Fast inlined test
96 bool test(uint elem) const {
97 uint32_t word = elem >> word_bits;
98 if (word >= _size) {
99 return false;
100 }
101 uint32_t mask = 1U << (elem & bit_mask);
102 return (_data[word] & mask) != 0;
103 }
104
105 void remove(uint elem) {
106 uint32_t word = elem >> word_bits;
107 if (word >= _size) {
108 return;
109 }
110 uint32_t mask = 1U << (elem & bit_mask);
111 _data[word] &= ~mask; // Clear bit
112 }
113
114 // Fast inlined set
115 void set(uint elem) {
116 uint32_t word = elem >> word_bits;
117 maybe_grow(word);
118 uint32_t mask = 1U << (elem & bit_mask);
119 _data[word] |= mask;
120 }
121 };
122
123 #endif // SHARE_LIBADT_VECTSET_HPP