/*
 * Copyright (C) 2014 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef ART_LIBARTBASE_BASE_HASH_MAP_H_
#define ART_LIBARTBASE_BASE_HASH_MAP_H_

#include <utility>

#include "hash_set.h"

namespace art {

template <typename Fn>
class HashMapWrapper {
 public:
  // Hash function.
  template <class Key, class Value>
  size_t operator()(const std::pair<Key, Value>& pair) const {
    return fn_(pair.first);
  }
  template <class Key>
  size_t operator()(const Key& key) const {
    return fn_(key);
  }
  template <class Key, class Value>
  bool operator()(const std::pair<Key, Value>& a, const std::pair<Key, Value>& b) const {
    return fn_(a.first, b.first);
  }
  template <class Key, class Value, class Element>
  bool operator()(const std::pair<Key, Value>& a, const Element& element) const {
    return fn_(a.first, element);
  }

 private:
  Fn fn_;
};

template <typename Key, typename Value>
class DefaultMapEmptyFn {
 public:
  void MakeEmpty(std::pair<Key, Value>& item) const {
    item = std::pair<Key, Value>();
  }
  bool IsEmpty(const std::pair<Key, Value>& item) const {
    return item.first == Key();
  }
};

template <class Key,
          class Value,
          class EmptyFn = DefaultMapEmptyFn<Key, Value>,
          class HashFn = DefaultHashFn<Key>,
          class Pred = DefaultPred<Key>,
          class Alloc = std::allocator<std::pair<Key, Value>>>
class HashMap : public HashSet<std::pair<Key, Value>,
                               EmptyFn,
                               HashMapWrapper<HashFn>,
                               HashMapWrapper<Pred>,
                               Alloc> {
 private:
  using Base = HashSet<std::pair<Key, Value>,
                       EmptyFn,
                       HashMapWrapper<HashFn>,
                       HashMapWrapper<Pred>,
                       Alloc>;

 public:
  HashMap() : Base() { }
  explicit HashMap(const Alloc& alloc)
      : Base(alloc) { }
};

}  // namespace art

#endif  // ART_LIBARTBASE_BASE_HASH_MAP_H_