/*

 * Copyright (c) 2016, 2018, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 *

 */

#include "precompiled.hpp"

#include "jfr/recorder/stringpool/jfrStringPoolBuffer.hpp"

#include "runtime/atomic.hpp"

#include "runtime/thread.inline.hpp"

JfrStringPoolBuffer::JfrStringPoolBuffer() : JfrBuffer(), _string_count_pos(0), _string_count_top(0) {}

void JfrStringPoolBuffer::reinitialize() {

  concurrent_top();

  set_pos((start()));

  set_string_pos(0);

  set_string_top(0);

  set_concurrent_top(start());

}

uint64_t JfrStringPoolBuffer::string_pos() const {

  return OrderAccess::load_acquire(&_string_count_pos);

}

uint64_t JfrStringPoolBuffer::string_top() const {

  return OrderAccess::load_acquire(&_string_count_top);

}

uint64_t JfrStringPoolBuffer::string_count() const {

  return string_pos() - string_top();

}

void JfrStringPoolBuffer::set_string_pos(uint64_t value) {

  Atomic::store(value, &_string_count_pos);

}

void JfrStringPoolBuffer::increment(uint64_t value) {

#if !(defined(ARM) || defined(IA32))

  Atomic::add(value, &_string_count_pos);

#else

  // TODO: This should be fixed in Atomic::add handling for 32-bit platforms,

  // see JDK-8203283. We workaround the absence of support right here.

  uint64_t cur, val;

  do {

     cur = Atomic::load(&_string_count_top);

     val = cur + value;

  } while (Atomic::cmpxchg(val, &_string_count_pos, cur) != cur);

#endif

}

void JfrStringPoolBuffer::set_string_top(uint64_t value) {

  Atomic::store(value, &_string_count_top);

}