/*

 * Copyright (c) 1997, 2010, 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_VM_OOPS_OBJARRAYOOP_HPP

#define SHARE_VM_OOPS_OBJARRAYOOP_HPP

#include "oops/arrayOop.hpp"

// An objArrayOop is an array containing oops.

// Evaluating "String arg[10]" will create an objArrayOop.

class objArrayOopDesc : public arrayOopDesc {

  friend class ObjArrayKlass;

  friend class Runtime1;

  friend class psPromotionManager;

  friend class CSetMarkOopClosure;

  friend class G1ParScanPartialArrayClosure;

  template <class T> T* obj_at_addr(int index) const {

    assert(is_within_bounds(index), "index out of bounds");

    return &((T*)base())[index];

  }

private:

  // Give size of objArrayOop in HeapWords minus the header

  static int array_size(int length) {

    const int OopsPerHeapWord = HeapWordSize/heapOopSize;

    assert(OopsPerHeapWord >= 1 && (HeapWordSize % heapOopSize == 0),

           "Else the following (new) computation would be in error");

#ifdef ASSERT

    // The old code is left in for sanity-checking; it'll

    // go away pretty soon. XXX

    // Without UseCompressedOops, this is simply:

    // oop->length() * HeapWordsPerOop;

    // With narrowOops, HeapWordsPerOop is 1/2 or equal 0 as an integer.

    // The oop elements are aligned up to wordSize

    const int HeapWordsPerOop = heapOopSize/HeapWordSize;

    int old_res;

    if (HeapWordsPerOop > 0) {

      old_res = length * HeapWordsPerOop;

    } else {

      old_res = align_size_up(length, OopsPerHeapWord)/OopsPerHeapWord;

    }

#endif  // ASSERT

    int res = ((uint)length + OopsPerHeapWord - 1)/OopsPerHeapWord;

    assert(res == old_res, "Inconsistency between old and new.");

    return res;

  }

 public:

  // Returns the offset of the first element.

  static int base_offset_in_bytes() {

    return arrayOopDesc::base_offset_in_bytes(T_OBJECT);

  }

  // base is the address following the header.

  HeapWord* base() const      { return (HeapWord*) arrayOopDesc::base(T_OBJECT); }

  // Accessing

  oop obj_at(int index) const {

    // With UseCompressedOops decode the narrow oop in the objArray to an

    // uncompressed oop.  Otherwise this is simply a "*" operator.

    if (UseCompressedOops) {

      return load_decode_heap_oop(obj_at_addr<narrowOop>(index));

    } else {

      return load_decode_heap_oop(obj_at_addr<oop>(index));

    }

  }

  void obj_at_put(int index, oop value) {

    if (UseCompressedOops) {

      oop_store(obj_at_addr<narrowOop>(index), value);

    } else {

      oop_store(obj_at_addr<oop>(index), value);

    }

  }

  // Sizing

  static int header_size()    { return arrayOopDesc::header_size(T_OBJECT); }

  int object_size()           { return object_size(length()); }

  static int object_size(int length) {

    // This returns the object size in HeapWords.

    uint asz = array_size(length);

    uint osz = align_object_size(header_size() + asz);

    assert(osz >= asz,   "no overflow");

    assert((int)osz > 0, "no overflow");

    return (int)osz;

  }

  // special iterators for index ranges, returns size of object

#define ObjArrayOop_OOP_ITERATE_DECL(OopClosureType, nv_suffix)     \

  int oop_iterate_range(OopClosureType* blk, int start, int end);

  ALL_OOP_OOP_ITERATE_CLOSURES_1(ObjArrayOop_OOP_ITERATE_DECL)

  ALL_OOP_OOP_ITERATE_CLOSURES_2(ObjArrayOop_OOP_ITERATE_DECL)

};

#endif // SHARE_VM_OOPS_OBJARRAYOOP_HPP