/* -*- 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_extender.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 reference map tag.
    typedef True ReferenceMapTag;

    /// The key type of the maps.
    typedef _Item Key;
    /// The value type of the map.
    typedef _Value Value;
    /// The const reference type of the map.
    typedef const _Value& ConstReference;
    /// The reference type of the map.
    typedef _Value& Reference;

    typedef const Value ConstValue;
    typedef Value* Pointer;
    typedef const Value* ConstPointer;

    typedef AlterationNotifier<_Item> Registry;

    /// The MapBase of the Map which imlements the core regisitry function.
    typedef typename Registry::ObserverBase Parent;
		


  private:
    typedef std::allocator<Value> Allocator;


  public:

    /// \brief Graph initialized map constructor.
    ///
    /// Graph 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());
      }								
    }

    /// \brief Constructor to use default value to initialize the map. 
    ///
    /// It constructs 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);
      }								
    }

    /// \brief Constructor to copy a map of the same map type.
    ///
    /// 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:

    /// \brief The subscript operator. 
    ///
    /// 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];
    } 
		
    /// \brief The const subscript operator.
    ///
    /// 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];
    }

    /// \brief Setter function of the map.
    ///	
    /// 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.
         
    virtual 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());
    }

    virtual 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.
     
    virtual void erase(const Key& key) {
      int id = graph->id(key);
      allocator.destroy(&(values[id]));
    }

    virtual 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]));
      }
    }

    virtual 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());
      }								
    }

    virtual 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