[98474f] | 1 | // -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- |
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| 2 | /*****************************************************************************\ |
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[fea494] | 3 | * Computer Algebra System SINGULAR |
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[98474f] | 4 | \*****************************************************************************/ |
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| 5 | /** @file Enumerator.h |
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| 6 | * |
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| 7 | * Abstract API for enumerators. |
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[fea494] | 8 | * |
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[98474f] | 9 | * ABSTRACT: Abstract interface for forward iteratable containers (enumerators) |
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| 10 | * of standalone objects (e.g. polynomials as sets of numbers), without any |
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[fea494] | 11 | * knowledge of their internals. |
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[98474f] | 12 | * |
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| 13 | * @author Oleksandr Motsak |
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| 14 | * |
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| 15 | * |
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| 16 | **/ |
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| 17 | /*****************************************************************************/ |
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| 18 | |
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| 19 | #ifndef ENUMERATOR_H |
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| 20 | #define ENUMERATOR_H |
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| 21 | |
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| 22 | /** @class IBaseEnumerator |
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[fea494] | 23 | * |
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[9952bd] | 24 | * Base enumerator interface for simple iteration over a generic collection. |
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[98474f] | 25 | * |
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[9952bd] | 26 | * Abstract API of enumerators for enumerable collections of standalone objects. |
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| 27 | * Just like IEnumerator from C#. Usage pattern can be as follows: |
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[98474f] | 28 | * |
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| 29 | * @code |
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[9952bd] | 30 | * IBaseEnumerator& itr = ...; |
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| 31 | * itr.Reset(); // goes to the "-1" element |
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| 32 | * // NOTE: itr is not useable here! |
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| 33 | * while( itr.MoveNext() ) |
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[98474f] | 34 | * { |
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| 35 | * do something custom with itr... |
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| 36 | * } |
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| 37 | * @endcode |
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| 38 | * |
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[fea494] | 39 | * Note that the Reset() |
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[98474f] | 40 | * |
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| 41 | * @sa IEnumerator |
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| 42 | */ |
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| 43 | class IBaseEnumerator // IDisposable |
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| 44 | { |
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| 45 | public: |
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| 46 | /// Advances the enumerator to the next element of the collection. |
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| 47 | /// returns true if the enumerator was successfully advanced to the |
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| 48 | /// next element; |
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| 49 | /// false if the enumerator has passed the end of the collection. |
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[fea494] | 50 | virtual bool MoveNext() = 0; |
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[98474f] | 51 | |
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[9952bd] | 52 | /// Sets the enumerator to its initial position: -1, |
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| 53 | /// which is before the first element in the collection. |
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[98474f] | 54 | virtual void Reset() = 0; |
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[9952bd] | 55 | |
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[dc79bd] | 56 | /// Current position is inside the collection (not -1 or past the end) |
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| 57 | virtual bool IsValid() const = 0; |
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[fea494] | 58 | |
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[9952bd] | 59 | private: |
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[88615db] | 60 | /// disable copy constructor and assignment operator |
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[9952bd] | 61 | IBaseEnumerator(const IBaseEnumerator&); |
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| 62 | void operator=(const IBaseEnumerator&); |
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| 63 | |
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| 64 | protected: |
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| 65 | IBaseEnumerator(){} |
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[dc79bd] | 66 | ~IBaseEnumerator() {} // TODO: needed? |
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| 67 | |
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[9952bd] | 68 | |
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[98474f] | 69 | }; |
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| 70 | |
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| 71 | |
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| 72 | /** @class IAccessor |
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[fea494] | 73 | * |
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[98474f] | 74 | * Templated accessor interface for accessing individual data (for instance, of an enumerator). |
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| 75 | * |
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| 76 | * T is the type of objects to access, available via the Current() method. |
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| 77 | * |
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| 78 | * @sa IBaseEnumerator |
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| 79 | */ |
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| 80 | template <typename T> |
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| 81 | class IAccessor // IDisposable |
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| 82 | { |
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| 83 | public: |
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| 84 | typedef T value_type; |
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| 85 | typedef value_type& reference; |
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| 86 | typedef const value_type& const_reference; |
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| 87 | |
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| 88 | /// Gets the current element in the collection (read and write). |
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| 89 | virtual reference Current() = 0; |
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| 90 | |
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| 91 | /// Gets the current element in the collection (read only). |
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| 92 | virtual const_reference Current() const = 0; |
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[9952bd] | 93 | |
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[dc79bd] | 94 | protected: |
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[fea494] | 95 | IAccessor(){} |
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[dc79bd] | 96 | ~IAccessor() {} // TODO: needed? |
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[fea494] | 97 | |
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[98474f] | 98 | }; |
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| 99 | |
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| 100 | /** @class IEnumerator |
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[fea494] | 101 | * |
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[9952bd] | 102 | * Templated enumerator interface for simple iteration over a generic collection of T's. |
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[98474f] | 103 | * |
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[9952bd] | 104 | * Abstract API of enumerators for generic enumerable collections of standalone |
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| 105 | * objects of type T. Inspired by IEnumerator from C#. Usage parrten can be as |
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[98474f] | 106 | * follows: |
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| 107 | * |
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| 108 | * @code |
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[9952bd] | 109 | * IEnumerator<T>& itr = ...; |
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[fea494] | 110 | * |
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[9952bd] | 111 | * itr.Reset(); // goes before the first element, thus no itr.Current() is available here! |
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[fea494] | 112 | * |
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[9952bd] | 113 | * while( itr.MoveNext() ) |
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[98474f] | 114 | * { |
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| 115 | * use/change itr.Current()... |
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| 116 | * } |
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| 117 | * @endcode |
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| 118 | * |
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| 119 | * T is the type of objects to enumerate, available via Current() method |
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| 120 | * |
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| 121 | * @sa IBaseEnumerator |
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| 122 | */ |
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| 123 | template <typename T> |
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| 124 | class IEnumerator: public virtual IBaseEnumerator, public virtual IAccessor<T> |
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| 125 | { |
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| 126 | public: |
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| 127 | }; |
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| 128 | |
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| 129 | #if 0 |
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| 130 | // the following is not used for now // |
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| 131 | |
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| 132 | // include basic definitions |
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| 133 | //??// #include <iterator> |
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| 134 | |
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| 135 | /** @class IBaseIterator |
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[fea494] | 136 | * |
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[98474f] | 137 | * A base abstract iterator API with virtualized standard iterator operators |
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| 138 | * |
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| 139 | * Abstract API for iterators that should work with STL and BOOST. |
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| 140 | * |
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| 141 | * @sa STL iterators |
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| 142 | */ |
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| 143 | template <class A> |
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| 144 | class IBaseIterator //??// : public std::iterator<std::forward_iterator_tag, A> |
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| 145 | { |
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| 146 | public: |
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| 147 | typedef IBaseIterator<A> self; |
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| 148 | typedef self& self_reference; |
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| 149 | typedef const self_reference const_self_reference; |
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| 150 | |
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| 151 | virtual bool operator==(const_self_reference rhs) = 0; |
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| 152 | |
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| 153 | /// ++itr, goes to the next state, returns the new state |
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| 154 | virtual self_reference operator++() = 0; |
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| 155 | |
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| 156 | /// itr++, goes to the next state, returns the previous state |
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| 157 | virtual self_reference operator++(int) = 0; |
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| 158 | |
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| 159 | virtual A& operator*() = 0; |
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| 160 | virtual A* operator->() = 0; |
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| 161 | |
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| 162 | inline bool operator!=(const_self_reference rhs){ return !((*this) == rhs); } |
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| 163 | }; |
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| 164 | |
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| 165 | /** @class AIterator |
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[fea494] | 166 | * |
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[88615db] | 167 | * An abstract iterator with virtualized assignment operator and |
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[98474f] | 168 | * constructors. |
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| 169 | * |
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| 170 | * Abstract API for iterators that should work with STL and BOOST. |
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| 171 | * |
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| 172 | * @sa STL iterators |
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| 173 | */ |
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| 174 | template <class A> |
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| 175 | class IIterator: public IBaseIterator<A> |
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| 176 | { |
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| 177 | public: |
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| 178 | typedef IIterator<A> self; |
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| 179 | typedef self& self_reference; |
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| 180 | typedef const self_reference const_self_reference; |
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| 181 | |
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| 182 | IIterator(){ void_constructor(); } |
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| 183 | |
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| 184 | IIterator(const_self_reference itr) { copy_constructor(itr); } |
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| 185 | |
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| 186 | virtual self_reference operator=(const_self_reference other) = 0; |
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| 187 | |
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| 188 | private: |
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| 189 | virtual void void_constructor() = 0; |
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| 190 | virtual void copy_constructor(const_self_reference itr) = 0; |
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| 191 | }; |
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| 192 | |
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| 193 | /** @class IContainer |
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[fea494] | 194 | * |
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[98474f] | 195 | * Container of standalone objects |
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| 196 | * |
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| 197 | * Abstract API for containers of objects and their iterators |
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| 198 | * |
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| 199 | * @sa STL containers and iterators |
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| 200 | */ |
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| 201 | template <class T> |
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| 202 | class IContainer |
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| 203 | { |
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| 204 | public: |
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| 205 | typedef T value_type; |
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| 206 | typedef value_type& reference; |
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| 207 | typedef const value_type& const_reference; |
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[fea494] | 208 | //??// typedef std::size_t size_type; |
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[98474f] | 209 | //??// virtual size_type size() const = 0; |
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| 210 | virtual bool empty() const = 0; |
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| 211 | |
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| 212 | typedef IIterator<reference> iterator; |
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| 213 | virtual iterator begin() = 0; |
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| 214 | virtual iterator end() = 0; |
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| 215 | |
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| 216 | typedef IIterator<const_reference> const_iterator; |
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| 217 | virtual const_iterator begin() const = 0; |
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| 218 | virtual const_iterator end() const = 0; |
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| 219 | }; |
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[fea494] | 220 | #endif |
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[98474f] | 221 | |
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| 222 | |
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[fea494] | 223 | #endif |
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[98474f] | 224 | /* #ifndef ENUMERATOR_H */ |
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| 225 | |
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| 226 | // Vi-modeline: vim: filetype=c:syntax:shiftwidth=2:tabstop=8:textwidth=0:expandtab |
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