/*

 * Copyright (c) 1999, 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.

 *

 */

#include "precompiled.hpp"

#include "ci/ciConstantPoolCache.hpp"

#include "ci/ciUtilities.hpp"

#include "memory/allocation.hpp"

#include "memory/allocation.inline.hpp"

// ciConstantPoolCache

//

// This class caches indexed constant pool lookups.

// ------------------------------------------------------------------

// ciConstantPoolCache::ciConstantPoolCache

ciConstantPoolCache::ciConstantPoolCache(Arena* arena,

                                 int expected_size) {

  _elements =

    new (arena) GrowableArray<void*>(arena, expected_size, 0, 0);

}

// ------------------------------------------------------------------

// ciConstantPoolCache::get

//

// Get the entry at some index

void* ciConstantPoolCache::get(int index) {

  ASSERT_IN_VM;

  int pos = find(index);

  if (pos >= _keys->length() ||

      _keys->at(pos) != index) {

    // This element is not present in the cache.

    return NULL;

  }

  return _elements->at(pos);

}

// ------------------------------------------------------------------

// ciConstantPoolCache::find

//

// Use binary search to find the position of this index in the cache.

// If there is no entry in the cache corresponding to this oop, return

// the position at which the index would be inserted.

int ciConstantPoolCache::find(int key) {

  int min = 0;

  int max = _keys->length()-1;

  while (max >= min) {

    int mid = (max + min) / 2;

    int value = _keys->at(mid);

    if (value < key) {

      min = mid + 1;

    } else if (value > key) {

      max = mid - 1;

    } else {

      return mid;

    }

  }

  return min;

}

// ------------------------------------------------------------------

// ciConstantPoolCache::insert

//

// Insert a ciObject into the table at some index.

void ciConstantPoolCache::insert(int index, void* elem) {

  int i;

  int pos = find(index);

  for (i = _keys->length()-1; i >= pos; i--) {

    _keys->at_put_grow(i+1, _keys->at(i));

    _elements->at_put_grow(i+1, _elements->at(i));

  }

  _keys->at_put_grow(pos, index);

  _elements->at_put_grow(pos, elem);

}

// ------------------------------------------------------------------

// ciConstantPoolCache::print

//

// Print debugging information about the cache.

void ciConstantPoolCache::print() {

  Unimplemented();

}