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