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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * 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).
 *
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 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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#ifndef SHARE_GC_PARALLEL_PSROOTTYPE_INLINE_HPP
#define SHARE_GC_PARALLEL_PSROOTTYPE_INLINE_HPP

#include "memory/allocation.hpp"
#include "runtime/atomic.hpp"
#include "utilities/globalDefinitions.hpp"

namespace Parallel { namespace RootType {
  enum Value {
    universe,
    jni_handles,
    //"threads" are handled in parallel as a special case
    object_synchronizer,
    system_dictionary,
    class_loader_data,
    management,
    jvmti,
    code_cache,
    JVMCI_ONLY(jvmci COMMA)
    sentinel
  };
}} // namespace Parallel::RootType

template <typename T>
class EnumClaimer : StackObj {
  volatile uint _counter;
  uint _to_exclusive;
public:
  EnumClaimer(T to_exclusive) : _counter(0), _to_exclusive(to_exclusive) {
    STATIC_ASSERT(sizeof(T) <= sizeof _counter);
    assert(_to_exclusive <= 20, "arbitrary (please change if needed), but we want to guard against /sparse/ bit-field like enumerations");
  }
  ~EnumClaimer() {
    assert(_counter >= _to_exclusive, "not all enumerations were claimed");
  }

  bool try_claim(T& enum_reference) {
    uint claimed = Atomic::add(1u, &_counter) - 1; // -1 is so that we start with zero
    if (claimed < _to_exclusive) {
      enum_reference = reinterpret_cast<T&>(claimed);
      return true;
    } else {
      return false;
    }
  }
};

#endif /* SHARE_GC_PARALLEL_PSROOTTYPE_INLINE_HPP */