1 /*
   2  * Copyright (c) 2012, 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 #include "precompiled.hpp"
  26 #include "services/memPtr.hpp"
  27 #include "services/memTracker.hpp"
  28 
  29 volatile jint SequenceGenerator::_seq_number = 1;
  30 volatile unsigned long SequenceGenerator::_generation = 1;
  31 NOT_PRODUCT(jint SequenceGenerator::_max_seq_number = 1;)
  32 
  33 jint SequenceGenerator::next() {
  34   jint seq = Atomic::add(1, &_seq_number);
  35   if (seq < 0) {
  36     MemTracker::shutdown(MemTracker::NMT_sequence_overflow);
  37   }
  38   assert(seq > 0, "counter overflow");
  39   NOT_PRODUCT(_max_seq_number = (seq > _max_seq_number) ? seq : _max_seq_number;)
  40   return seq;
  41 }
  42