lemon/concepts/maps.h
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     1 /* -*- C++ -*-
       
     2  *
       
     3  * This file is a part of LEMON, a generic C++ optimization library
       
     4  *
       
     5  * Copyright (C) 2003-2007
       
     6  * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
       
     7  * (Egervary Research Group on Combinatorial Optimization, EGRES).
       
     8  *
       
     9  * Permission to use, modify and distribute this software is granted
       
    10  * provided that this copyright notice appears in all copies. For
       
    11  * precise terms see the accompanying LICENSE file.
       
    12  *
       
    13  * This software is provided "AS IS" with no warranty of any kind,
       
    14  * express or implied, and with no claim as to its suitability for any
       
    15  * purpose.
       
    16  *
       
    17  */
       
    18 
       
    19 #ifndef LEMON_CONCEPT_MAPS_H
       
    20 #define LEMON_CONCEPT_MAPS_H
       
    21 
       
    22 #include <lemon/bits/utility.h>
       
    23 #include <lemon/concept_check.h>
       
    24 
       
    25 ///\ingroup concept
       
    26 ///\file
       
    27 ///\brief Map concepts checking classes for testing and documenting.
       
    28 
       
    29 namespace lemon {
       
    30 
       
    31   namespace concepts {
       
    32   
       
    33     /// \addtogroup concept
       
    34     /// @{
       
    35 
       
    36     /// Readable map concept
       
    37     template<typename K, typename T>
       
    38     class ReadMap
       
    39     {
       
    40     public:
       
    41       /// Map's key type.
       
    42       typedef K Key;    
       
    43       /// Map's value type. (The type of objects associated with the keys).
       
    44       typedef T Value;
       
    45 
       
    46       /// Returns the value associated with a key.
       
    47 
       
    48       /// \bug Value should n't need to be default constructible.
       
    49       ///
       
    50       Value operator[](const Key &) const {return Value();}
       
    51 
       
    52       template<typename _ReadMap>
       
    53       struct Constraints {
       
    54 
       
    55 	void constraints() {
       
    56 	  Value val = m[key];
       
    57 	  val = m[key];
       
    58 	  typename _ReadMap::Value own_val = m[own_key]; 
       
    59 	  own_val = m[own_key]; 
       
    60 
       
    61 	  ignore_unused_variable_warning(val);
       
    62 	  ignore_unused_variable_warning(own_val);
       
    63 	  ignore_unused_variable_warning(key);
       
    64 	}
       
    65 	Key& key;
       
    66 	typename _ReadMap::Key& own_key;
       
    67 	_ReadMap& m;
       
    68       };
       
    69       
       
    70     };
       
    71 
       
    72 
       
    73     /// Writable map concept
       
    74     template<typename K, typename T>
       
    75     class WriteMap
       
    76     {
       
    77     public:
       
    78       /// Map's key type.
       
    79       typedef K Key;    
       
    80       /// Map's value type. (The type of objects associated with the keys).
       
    81       typedef T Value;
       
    82 
       
    83       /// Sets the value associated with a key.
       
    84       void set(const Key &,const Value &) {}
       
    85 
       
    86       ///Default constructor
       
    87       WriteMap() {}
       
    88 
       
    89       template <typename _WriteMap>
       
    90       struct Constraints {
       
    91 	void constraints() {
       
    92 	  // No constraints for constructor.
       
    93 	  m.set(key, val);
       
    94 	  m.set(own_key, own_val);
       
    95 	  ignore_unused_variable_warning(key);
       
    96 	  ignore_unused_variable_warning(val);
       
    97 	  ignore_unused_variable_warning(own_key);
       
    98 	  ignore_unused_variable_warning(own_val);
       
    99 	}
       
   100 
       
   101 	Value& val;
       
   102 	typename _WriteMap::Value own_val;
       
   103 	Key& key;
       
   104 	typename _WriteMap::Key& own_key;
       
   105 	_WriteMap& m;
       
   106 
       
   107       };
       
   108     };
       
   109 
       
   110     ///Read/Writable map concept
       
   111     template<typename K, typename T>
       
   112     class ReadWriteMap : public ReadMap<K,T>,
       
   113 			    public WriteMap<K,T>
       
   114     {
       
   115     public:
       
   116       /// Map's key type.
       
   117       typedef K Key;    
       
   118       /// Map's value type. (The type of objects associated with the keys).
       
   119       typedef T Value;
       
   120 
       
   121       /// Returns the value associated with a key.
       
   122       Value operator[](const Key &) const {return Value();}
       
   123       /// Sets the value associated with a key.
       
   124       void set(const Key & ,const Value &) {}
       
   125 
       
   126       template<typename _ReadWriteMap>
       
   127       struct Constraints {
       
   128 	void constraints() {
       
   129 	  checkConcept<ReadMap<K, T>, _ReadWriteMap >();
       
   130 	  checkConcept<WriteMap<K, T>, _ReadWriteMap >();
       
   131 	}
       
   132       };
       
   133     };
       
   134   
       
   135   
       
   136     ///Dereferable map concept
       
   137     template<typename K, typename T, typename R, typename CR>
       
   138     class ReferenceMap : public ReadWriteMap<K,T>
       
   139     {
       
   140     public:
       
   141       /// Tag for reference maps.
       
   142       typedef True ReferenceMapTag;
       
   143       /// Map's key type.
       
   144       typedef K Key;    
       
   145       /// Map's value type. (The type of objects associated with the keys).
       
   146       typedef T Value;
       
   147       /// Map's reference type.
       
   148       typedef R Reference;
       
   149       /// Map's const reference type.
       
   150       typedef CR ConstReference;
       
   151 
       
   152     protected:
       
   153       Value tmp;
       
   154     public:
       
   155 
       
   156       ///Returns a reference to the value associated to a key.
       
   157       Reference operator[](const Key &) { return tmp; }
       
   158       ///Returns a const reference to the value associated to a key.
       
   159       ConstReference operator[](const Key &) const
       
   160       { return tmp; }
       
   161       /// Sets the value associated with a key.
       
   162       void set(const Key &k,const Value &t) { operator[](k)=t; }
       
   163 
       
   164       // \todo rethink this concept
       
   165       template<typename _ReferenceMap>
       
   166       struct ReferenceMapConcept {
       
   167 
       
   168 	void constraints() {
       
   169 	  checkConcept<ReadWriteMap, _ReferenceMap >();
       
   170 	  m[key] = val;
       
   171 	  val  = m[key];
       
   172 	  m[key] = ref;
       
   173 	  ref = m[key];
       
   174 	  m[own_key] = own_val;
       
   175 	  own_val  = m[own_key];
       
   176 	  m[own_key] = own_ref;
       
   177 	  own_ref = m[own_key];	  	  
       
   178 	}
       
   179 
       
   180 	typename _ReferenceMap::Key& own_key;
       
   181 	typename _ReferenceMap::Value& own_val;
       
   182 	typename _ReferenceMap::Reference& own_ref;
       
   183 	Key& key;
       
   184 	Value& val;
       
   185 	Reference& ref;
       
   186 	_ReferenceMap& m;
       
   187       };
       
   188     };
       
   189 
       
   190     // @}
       
   191 
       
   192   } //namespace concepts
       
   193 } //namespace lemon
       
   194 #endif // LEMON_CONCEPT_MAPS_H