/* -*- C++ -*-

 * lemon/bits/array_map.h - Part of LEMON, a generic C++ optimization library

 *

 * Copyright (C) 2005 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport

 * (Egervary Research Group on Combinatorial Optimization, EGRES).

 *

 * Permission to use, modify and distribute this software is granted

 * provided that this copyright notice appears in all copies. For

 * precise terms see the accompanying LICENSE file.

 *

 * This software is provided "AS IS" with no warranty of any kind,

 * express or implied, and with no claim as to its suitability for any

 * purpose.

 *

 */

#ifndef LEMON_ARRAY_MAP_H

#define LEMON_ARRAY_MAP_H

#include <memory>

#include <lemon/bits/map_iterator.h>

#include <lemon/concept_check.h>

#include <lemon/concept/maps.h>

/// \ingroup graphmapfactory

/// \file

/// \brief Graph maps that construct and destruct

/// their elements dynamically.

namespace lemon {

  /// \ingroup graphmapfactory

  ///

  /// \brief Graph map based on the array storage.

  ///

  /// The ArrayMap template class is graph map structure what

  /// automatically updates the map when a key is added to or erased from

  /// the map. This map uses the allocators to implement 

  /// the container functionality.

  ///

  /// The template parameter is the AlterationNotifier that the maps

  /// will belong to and the Value.

  template <typename _Graph, 

	    typename _Item,

	    typename _Value>

  class ArrayMap : public AlterationNotifier<_Item>::ObserverBase {

    typedef _Item Item;

  public:

    /// The graph type of the maps. 

    typedef _Graph Graph;

    /// The key type of the maps.

    typedef _Item Key;

    typedef AlterationNotifier<_Item> Registry;

    /// The MapBase of the Map which imlements the core regisitry function.

    typedef typename Registry::ObserverBase Parent;

    /// The value type of the map.

    typedef _Value Value;

  private:

    typedef std::allocator<Value> Allocator;

  public:

    /// Graph and Registry initialized map constructor.

    ArrayMap(const Graph& _g) : graph(&_g) {

      Item it;

      attach(_g.getNotifier(Item()));

      allocate_memory();

      for (graph->first(it); it != INVALID; graph->next(it)) {

	int id = graph->id(it);;

	allocator.construct(&(values[id]), Value());

      }								

    }

    /// Constructor to use default value to initialize the map. 

    /// It constrates a map and initialize all of the the map. 

    ArrayMap(const Graph& _g, const Value& _v) : graph(&_g) {

      Item it;

      attach(_g.getNotifier(_Item()));

      allocate_memory();

      for (graph->first(it); it != INVALID; graph->next(it)) {

	int id = graph->id(it);;

	allocator.construct(&(values[id]), _v);

      }								

    }

    /// Constructor to copy a map of the same map type.

    ArrayMap(const ArrayMap& copy) : Parent(), graph(copy.graph) {

      if (copy.attached()) {

	attach(*copy.getRegistry());

      }

      capacity = copy.capacity;

      if (capacity == 0) return;

      values = allocator.allocate(capacity);

      Item it;

      for (graph->first(it); it != INVALID; graph->next(it)) {

	int id = graph->id(it);;

	allocator.construct(&(values[id]), copy.values[id]);

      }

    }

    /// \brief The destructor of the map.

    ///     

    /// The destructor of the map.

    virtual ~ArrayMap() {      

      if (attached()) {

	clear();

	detach();

      }

    }

  private:

    ArrayMap& operator=(const ArrayMap&);

  protected:

    using Parent::attach;

    using Parent::detach;

    using Parent::attached;

    const Graph* getGraph() {

      return graph;

    }

  public:

    ///The subscript operator. The map can be subscripted by the

    ///actual keys of the graph. 

    Value& operator[](const Key& key) {

      int id = graph->id(key);

      return values[id];

    } 

    ///The const subscript operator. The map can be subscripted by the

    ///actual keys of the graph. 

    const Value& operator[](const Key& key) const {

      int id = graph->id(key);

      return values[id];

    }

    /// Setter function of the map. Equivalent with map[key] = val.

    /// This is a compatibility feature with the not dereferable maps.

    void set(const Key& key, const Value& val) {

      (*this)[key] = val;

    }

  protected:

    /// Add a new key to the map. It called by the map registry.

    void add(const Key& key) {

      int id = graph->id(key);

      if (id >= capacity) {

	int new_capacity = (capacity == 0 ? 1 : capacity);

	while (new_capacity <= id) {

	  new_capacity <<= 1;

	}

	Value* new_values = allocator.allocate(new_capacity);

	Item it;

	for (graph->first(it); it != INVALID; graph->next(it)) {

	  int jd = graph->id(it);;

	  if (id != jd) {

	    allocator.construct(&(new_values[jd]), values[jd]);

	    allocator.destroy(&(values[jd]));

	  }

	}

	if (capacity != 0) allocator.deallocate(values, capacity);

	values = new_values;

	capacity = new_capacity;

      }

      allocator.construct(&(values[id]), Value());

    }

    void add(const std::vector<Key>& keys) {

      int max_id = -1;

      for (int i = 0; i < (int)keys.size(); ++i) {

	int id = graph->id(keys[i]);

	if (id > max_id) {

	  max_id = id;

	}

      }

      if (max_id >= capacity) {

	int new_capacity = (capacity == 0 ? 1 : capacity);

	while (new_capacity <= max_id) {

	  new_capacity <<= 1;

	}

	Value* new_values = allocator.allocate(new_capacity);

	Item it;

	for (graph->first(it); it != INVALID; graph->next(it)) {

	  int id = graph->id(it);

	  bool found = false;

	  for (int i = 0; i < (int)keys.size(); ++i) {

	    int jd = graph->id(keys[i]);

	    if (id == jd) {

	      found = true;

	      break;

	    }

	  }

	  if (found) continue;

	  allocator.construct(&(new_values[id]), values[id]);

	  allocator.destroy(&(values[id]));

	}

	if (capacity != 0) allocator.deallocate(values, capacity);

	values = new_values;

	capacity = new_capacity;

      }

      for (int i = 0; i < (int)keys.size(); ++i) {

	int id = graph->id(keys[i]);

	allocator.construct(&(values[id]), Value());

      }

    }

    /// Erase a key from the map. It called by the map registry.

    void erase(const Key& key) {

      int id = graph->id(key);

      allocator.destroy(&(values[id]));

    }

    void erase(const std::vector<Key>& keys) {

      for (int i = 0; i < (int)keys.size(); ++i) {

	int id = graph->id(keys[i]);

	allocator.destroy(&(values[id]));

      }

    }

    void build() {

      allocate_memory();

      Item it;

      for (graph->first(it); it != INVALID; graph->next(it)) {

	int id = graph->id(it);;

	allocator.construct(&(values[id]), Value());

      }								

    }

    void clear() {	

      if (capacity != 0) {

	Item it;

	for (graph->first(it); it != INVALID; graph->next(it)) {

	  int id = graph->id(it);

	  allocator.destroy(&(values[id]));

	}								

	allocator.deallocate(values, capacity);

	capacity = 0;

      }

    }

  private:

    void allocate_memory() {

      int max_id = graph->maxId(_Item());

      if (max_id == -1) {

	capacity = 0;

	values = 0;

	return;

      }

      capacity = 1;

      while (capacity <= max_id) {

	capacity <<= 1;

      }

      values = allocator.allocate(capacity);	

    }      

    const Graph* graph;

    int capacity;

    Value* values;

    Allocator allocator;

  };		

}

#endif //LEMON_ARRAY_MAP_H