/*

 * Copyright (c) 2003, 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

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 */

#ifndef SHARE_VM_UTILITIES_HASHTABLE_INLINE_HPP

#define SHARE_VM_UTILITIES_HASHTABLE_INLINE_HPP

#include "memory/allocation.inline.hpp"

#include "utilities/hashtable.hpp"

// Inline function definitions for hashtable.hpp.

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

// Hash function

// We originally used hashpjw, but hash P(31) gives just as good results

// and is slighly faster. We would like a hash function that looks at every

// character, since package names have large common prefixes, and also because

// hash_or_fail does error checking while iterating.

// hash P(31) from Kernighan & Ritchie

  unsigned int h = 0;

  while (len-- > 0) {

    h = 31*h + (unsigned) *s;

    s++;

  }

  return h;

}

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

// Initialize a table.

inline BasicHashtable::BasicHashtable(int table_size, int entry_size) {

  // Called on startup, no locking needed

  initialize(table_size, entry_size, 0);

  _buckets = NEW_C_HEAP_ARRAY(HashtableBucket, table_size);

  for (int index = 0; index < _table_size; index++) {

    _buckets[index].clear();

  }

}

inline BasicHashtable::BasicHashtable(int table_size, int entry_size,

                                      HashtableBucket* buckets,

                                      int number_of_entries) {

  // Called on startup, no locking needed

  initialize(table_size, entry_size, number_of_entries);

  _buckets = buckets;

}

inline void BasicHashtable::initialize(int table_size, int entry_size,

                                       int number_of_entries) {

  // Called on startup, no locking needed

  _table_size = table_size;

  _entry_size = entry_size;

  _free_list = NULL;

  _first_free_entry = NULL;

  _end_block = NULL;

  _number_of_entries = number_of_entries;

#ifdef ASSERT

  _lookup_count = 0;

  _lookup_length = 0;

#endif

}

// The following method is MT-safe and may be used with caution.

inline BasicHashtableEntry* BasicHashtable::bucket(int i) {

  return _buckets[i].get_entry();

}

inline void HashtableBucket::set_entry(BasicHashtableEntry* l) {

  // Warning: Preserve store ordering.  The SystemDictionary is read

  //          without locks.  The new SystemDictionaryEntry must be

  //          complete before other threads can be allowed to see it

  //          via a store to _buckets[index].

  OrderAccess::release_store_ptr(&_entry, l);

}

inline BasicHashtableEntry* HashtableBucket::get_entry() const {

  // Warning: Preserve load ordering.  The SystemDictionary is read

  //          without locks.  The new SystemDictionaryEntry must be

  //          complete before other threads can be allowed to see it

  //          via a store to _buckets[index].

  return (BasicHashtableEntry*) OrderAccess::load_ptr_acquire(&_entry);

}

inline void BasicHashtable::set_entry(int index, BasicHashtableEntry* entry) {

  _buckets[index].set_entry(entry);

}

inline void BasicHashtable::add_entry(int index, BasicHashtableEntry* entry) {

  entry->set_next(bucket(index));

  _buckets[index].set_entry(entry);

  ++_number_of_entries;

}

inline void BasicHashtable::free_entry(BasicHashtableEntry* entry) {

  entry->set_next(_free_list);

  _free_list = entry;

  --_number_of_entries;

}

#endif // SHARE_VM_UTILITIES_HASHTABLE_INLINE_HPP