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1 // -*- C++ -*- // |
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2 #ifndef HUGO_MAPS_H |
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3 #define HUGO_MAPS_H |
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4 |
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5 ///\file |
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6 ///\brief Miscellaneous property maps |
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7 /// |
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8 ///\todo This file has the same name as the concept file in skeletons, |
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9 /// and this is not easily detectable in docs... |
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10 |
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11 #include <map> |
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12 |
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13 namespace hugo { |
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14 |
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15 /// Null map. (aka DoNothingMap) |
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16 |
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17 /// If you have to provide a map only for its type definitions, |
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18 /// or if you have to provide a writable map, but will not use the |
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19 /// data written to it... |
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20 template<typename K, typename T> |
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21 class NullMap |
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22 { |
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23 public: |
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24 typedef K KeyType; |
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25 typedef T ValueType; |
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26 |
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27 T operator[](const K&) const { return T(); } |
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28 void set(const K&, const T&) {} |
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29 }; |
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30 |
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31 |
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32 /// Constant map. |
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33 |
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34 /// This is a readable map which assignes a specified value to each key. |
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35 /// In other aspects it is equivalent to the \ref NullMap |
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36 template<typename K, typename T> |
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37 class ConstMap |
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38 { |
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39 T v; |
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40 public: |
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41 typedef K KeyType; |
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42 typedef T ValueType; |
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43 |
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44 ConstMap() {} |
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45 ConstMap(const T &_v) : v(_v) {} |
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46 |
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47 T operator[](const K&) const { return v; } |
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48 void set(const K&, const T&) {} |
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49 |
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50 template<typename T1> |
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51 struct rebind { |
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52 typedef ConstMap<K,T1> other; |
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53 }; |
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54 |
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55 template<typename T1> |
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56 ConstMap(const ConstMap<K,T1> &, const T &_v) : v(_v) {} |
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57 }; |
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58 |
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59 |
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60 |
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61 /// \c std::map wrapper |
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62 |
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63 /// This is essentially a wrapper for \c std::map. With addition that |
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64 /// you can specify a default value different from \c ValueType() . |
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65 /// |
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66 /// \todo Provide allocator parameter... |
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67 template <typename Key, typename T, typename Compare = std::less<Key> > |
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68 class StdMap : public std::map<Key,T,Compare> { |
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69 typedef std::map<Key,T,Compare> parent; |
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70 T v; |
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71 typedef typename parent::value_type PairType; |
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72 |
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73 public: |
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74 typedef Key KeyType; |
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75 typedef T ValueType; |
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76 typedef T& ReferenceType; |
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77 typedef const T& ConstReferenceType; |
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78 |
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79 |
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80 StdMap() {} |
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81 /// Constructor with specified default value |
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82 StdMap(const T& _v) : v(_v) {} |
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83 |
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84 /// \brief Constructs the map from an appropriate std::map. |
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85 /// |
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86 /// \warning Inefficient: copies the content of \c m ! |
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87 StdMap(const parent &m) : parent(m) {} |
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88 /// \brief Constructs the map from an appropriate std::map, and explicitly |
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89 /// specifies a default value. |
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90 /// |
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91 /// \warning Inefficient: copies the content of \c m ! |
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92 StdMap(const parent &m, const T& _v) : parent(m), v(_v) {} |
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93 |
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94 template<typename T1, typename Comp1> |
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95 StdMap(const StdMap<Key,T1,Comp1> &m, const T &_v) { FIXME; } |
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96 |
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97 ReferenceType operator[](const Key &k) { |
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98 return ( *( (insert(PairType(k,v))).first ) ).second; |
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99 } |
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100 ConstReferenceType operator[](const Key &k) const { |
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101 typename parent::iterator i = lower_bound(__k); |
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102 if (i == end() || key_comp()(k, (*i).first)) |
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103 return v; |
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104 return (*i).second; |
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105 } |
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106 void set(const Key &k, const T &t) { parent::operator[](k)=t; } |
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107 |
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108 /// Changes the default value of the map. |
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109 /// \return Returns the previous default value. |
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110 /// |
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111 /// \warning The value of some keys (which has alredy been queried, but |
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112 /// the value has been unchanged from the default) may change! |
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113 T setDefault(const T &_v) { T old=v; v=_v; return old; } |
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114 |
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115 template<typename T1> |
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116 struct rebind { |
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117 typedef StdMap<Key,T1,Compare> other; |
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118 }; |
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119 }; |
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120 |
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121 } |
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122 #endif // HUGO_MAPS_H |