1 /*
2 * Copyright 2009 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 // Class Stack (below) grows and shrinks by linking together "segments" which
26 // are allocated on demand. Segments are arrays of the element type (E) plus an
27 // extra pointer-sized field to store the segment link. Recently emptied
28 // segments are kept in a cache and reused.
29 //
30 // Notes/caveats:
31 //
32 // The size of an element must either evenly divide the size of a pointer or be
33 // a multiple of the size of a pointer.
34 //
35 // Destructors are not called for elements popped off the stack, so element
36 // types which rely on destructors for things like reference counting will not
37 // work properly.
38 //
39 // Class Stack allocates segments from the C heap. However, two protected
40 // virtual methods are used to alloc/free memory which subclasses can override:
41 //
42 // virtual void* alloc(size_t bytes);
43 // virtual void free(void* addr, size_t bytes);
44 //
185
186 Stack<E>& stack() const { return _stack; }
187
188 bool is_empty() const { return _cur_seg == NULL; }
189
190 E next() { return *next_addr(); }
191 E* next_addr();
192
193 void sync(); // Sync the iterator's state to the stack's current state.
194
195 private:
196 Stack<E>& _stack;
197 size_t _cur_seg_size;
198 E* _cur_seg;
199 size_t _full_seg_size;
200 };
201
202 #ifdef __GNUC__
203 #undef inline
204 #endif // __GNUC__
|
1 /*
2 * Copyright (c) 2009, 2010, 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_STACK_HPP
26 #define SHARE_VM_UTILITIES_STACK_HPP
27
28 #include "memory/allocation.inline.hpp"
29
30 // Class Stack (below) grows and shrinks by linking together "segments" which
31 // are allocated on demand. Segments are arrays of the element type (E) plus an
32 // extra pointer-sized field to store the segment link. Recently emptied
33 // segments are kept in a cache and reused.
34 //
35 // Notes/caveats:
36 //
37 // The size of an element must either evenly divide the size of a pointer or be
38 // a multiple of the size of a pointer.
39 //
40 // Destructors are not called for elements popped off the stack, so element
41 // types which rely on destructors for things like reference counting will not
42 // work properly.
43 //
44 // Class Stack allocates segments from the C heap. However, two protected
45 // virtual methods are used to alloc/free memory which subclasses can override:
46 //
47 // virtual void* alloc(size_t bytes);
48 // virtual void free(void* addr, size_t bytes);
49 //
190
191 Stack<E>& stack() const { return _stack; }
192
193 bool is_empty() const { return _cur_seg == NULL; }
194
195 E next() { return *next_addr(); }
196 E* next_addr();
197
198 void sync(); // Sync the iterator's state to the stack's current state.
199
200 private:
201 Stack<E>& _stack;
202 size_t _cur_seg_size;
203 E* _cur_seg;
204 size_t _full_seg_size;
205 };
206
207 #ifdef __GNUC__
208 #undef inline
209 #endif // __GNUC__
210
211 #endif // SHARE_VM_UTILITIES_STACK_HPP
|