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comparison src/share/vm/memory/memRegion.hpp @ 0:a61af66fc99e jdk7-b24

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author duke
date Sat, 01 Dec 2007 00:00:00 +0000
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children c18cbe5936b8
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-1:000000000000 0:a61af66fc99e
1 /*
2 * Copyright 2000-2004 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
24
25 // A very simple data structure representing a contigous region
26 // region of address space.
27
28 // Note that MemRegions are passed by value, not by reference.
29 // The intent is that they remain very small and contain no
30 // objects.
31
32 class MemRegion VALUE_OBJ_CLASS_SPEC {
33 friend class VMStructs;
34 private:
35 HeapWord* _start;
36 size_t _word_size;
37
38 public:
39 MemRegion() : _start(NULL), _word_size(0) {};
40 MemRegion(HeapWord* start, size_t word_size) :
41 _start(start), _word_size(word_size) {};
42 MemRegion(HeapWord* start, HeapWord* end) :
43 _start(start), _word_size(pointer_delta(end, start)) {
44 assert(end >= start, "incorrect constructor arguments");
45 }
46
47 MemRegion(const MemRegion& mr): _start(mr._start), _word_size(mr._word_size) {}
48
49 MemRegion intersection(const MemRegion mr2) const;
50 // regions must overlap or be adjacent
51 MemRegion _union(const MemRegion mr2) const;
52 // minus will fail a guarantee if mr2 is interior to this,
53 // since there's no way to return 2 disjoint regions.
54 MemRegion minus(const MemRegion mr2) const;
55
56 HeapWord* start() const { return _start; }
57 HeapWord* end() const { return _start + _word_size; }
58 HeapWord* last() const { return _start + _word_size - 1; }
59
60 void set_start(HeapWord* start) { _start = start; }
61 void set_end(HeapWord* end) { _word_size = pointer_delta(end, _start); }
62 void set_word_size(size_t word_size) {
63 _word_size = word_size;
64 }
65
66 bool contains(const MemRegion mr2) const {
67 return _start <= mr2._start && end() >= mr2.end();
68 }
69 bool contains(const void* addr) const {
70 return addr >= (void*)_start && addr < (void*)end();
71 }
72 bool equals(const MemRegion mr2) const {
73 // first disjunct since we do not have a canonical empty set
74 return ((is_empty() && mr2.is_empty()) ||
75 (start() == mr2.start() && end() == mr2.end()));
76 }
77
78 size_t byte_size() const { return _word_size * sizeof(HeapWord); }
79 size_t word_size() const { return _word_size; }
80
81 bool is_empty() const { return word_size() == 0; }
82 };
83
84 // For iteration over MemRegion's.
85
86 class MemRegionClosure : public StackObj {
87 public:
88 virtual void do_MemRegion(MemRegion mr) = 0;
89 };
90
91 // A ResourceObj version of MemRegionClosure
92
93 class MemRegionClosureRO: public MemRegionClosure {
94 public:
95 void* operator new(size_t size, ResourceObj::allocation_type type) {
96 return ResourceObj::operator new(size, type);
97 }
98 void* operator new(size_t size, Arena *arena) {
99 return ResourceObj::operator new(size, arena);
100 }
101 void* operator new(size_t size) {
102 return ResourceObj::operator new(size);
103 }
104
105 void operator delete(void* p) {} // nothing to do
106 };