/*

 * Copyright (c) 2015, 2017, 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.

 */

#ifndef SHARE_GC_Z_ZFORWARDING_INLINE_HPP

#define SHARE_GC_Z_ZFORWARDING_INLINE_HPP

#include "gc/z/zForwardingTable.hpp"

#include "gc/z/zGlobals.hpp"

#include "gc/z/zHash.inline.hpp"

#include "runtime/atomic.hpp"

#include "utilities/debug.hpp"

inline ZForwardingTable::ZForwardingTable() :

    _table(NULL),

    _size(0) {}

inline ZForwardingTable::~ZForwardingTable() {

  assert(is_null(), "Should be empty");

}

inline ZForwardingTableEntry ZForwardingTable::at(ZForwardingTableCursor* cursor) const {

  return _table[*cursor];

}

inline ZForwardingTableEntry ZForwardingTable::first(uintptr_t from_index, ZForwardingTableCursor* cursor) const {

  const size_t mask = _size - 1;

  const size_t hash = ZHash::uint32_to_uint32((uint32_t)from_index);

  *cursor = hash & mask;

  return at(cursor);

}

inline ZForwardingTableEntry ZForwardingTable::next(ZForwardingTableCursor* cursor) const {

  const size_t mask = _size - 1;

  *cursor = (*cursor + 1) & mask;

  return at(cursor);

}

inline bool ZForwardingTable::is_null() const {

  return _table == NULL;

}

inline ZForwardingTableEntry ZForwardingTable::find(uintptr_t from_index) const {

  ZForwardingTableCursor dummy;

  return find(from_index, &dummy);

}

inline ZForwardingTableEntry ZForwardingTable::find(uintptr_t from_index, ZForwardingTableCursor* cursor) const {

  // insertion into the table. This is safe because each entry is at

  // most updated once (from -1 to something else).

  ZForwardingTableEntry entry = first(from_index, cursor);

  while (!entry.is_empty()) {

    if (entry.from_index() == from_index) {

      // Match found, return matching entry

      return entry;

    }

    entry = next(cursor);

  }

  // Match not found, return empty entry

  return entry;

}

inline uintptr_t ZForwardingTable::insert(uintptr_t from_index, uintptr_t to_offset, ZForwardingTableCursor* cursor) {

  const ZForwardingTableEntry new_entry(from_index, to_offset);

  const ZForwardingTableEntry old_entry; // empty

  for (;;) {

    const ZForwardingTableEntry prev_entry = Atomic::cmpxchg(new_entry, _table + *cursor, old_entry);

    if (prev_entry.is_empty()) {

      // Success

      return to_offset;

    }

    // Find next empty or matching entry

    ZForwardingTableEntry entry = at(cursor);

    while (!entry.is_empty()) {

      if (entry.from_index() == from_index) {

        // Match found, return already inserted address

        return entry.to_offset();

      }

      entry = next(cursor);

    }

  }

}

#endif // SHARE_GC_Z_ZFORWARDING_INLINE_HPP