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 
  31 template <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(), err_msg("IOOBE i: " SIZE_FORMAT " size(): " SIZE_FORMAT, i, size()));
  77     return _values[i];
  78   }
  79 };
  80 
  81 #endif // SHARE_VM_UTILITIES_CHUNKED_LIST_HPP
--- EOF ---