Line data Source code
1 : /* Copyright (C) 2019 Wildfire Games.
2 : * This file is part of 0 A.D.
3 : *
4 : * 0 A.D. is free software: you can redistribute it and/or modify
5 : * it under the terms of the GNU General Public License as published by
6 : * the Free Software Foundation, either version 2 of the License, or
7 : * (at your option) any later version.
8 : *
9 : * 0 A.D. is distributed in the hope that it will be useful,
10 : * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 : * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 : * GNU General Public License for more details.
13 : *
14 : * You should have received a copy of the GNU General Public License
15 : * along with 0 A.D. If not, see <http://www.gnu.org/licenses/>.
16 : */
17 :
18 : #ifndef INCLUDED_DELTAARRAY
19 : #define INCLUDED_DELTAARRAY
20 :
21 0 : template<typename T> class DeltaArray2D
22 : {
23 : public:
24 0 : virtual ~DeltaArray2D() {}
25 :
26 : T get(ssize_t x, ssize_t y);
27 : void set(ssize_t x, ssize_t y, const T& val);
28 :
29 : void OverlayWith(const DeltaArray2D<T>& overlayer);
30 : void Undo();
31 : void Redo();
32 :
33 : protected:
34 : virtual T getOld(ssize_t x, ssize_t y) = 0;
35 : virtual void setNew(ssize_t x, ssize_t y, const T& val) = 0;
36 :
37 : private:
38 : // TODO: more efficient representation
39 : using Data = std::unordered_map<std::pair<ssize_t, ssize_t>, std::pair<T, T> >; // map of <x,y> -> <old_val, new_val>
40 : Data m_Data;
41 : };
42 :
43 : namespace std
44 : {
45 : template<>
46 : struct hash<std::pair<ssize_t, ssize_t> >
47 : {
48 0 : std::size_t operator()(const std::pair<ssize_t, ssize_t>& p) const
49 : {
50 0 : std::size_t seed = 0;
51 0 : hash_combine(seed, p.first << 16);
52 0 : hash_combine(seed, p.second);
53 0 : return seed;
54 : }
55 :
56 : // Same as boost::hash_combine
57 0 : void hash_combine(std::size_t& seed, const ssize_t val) const
58 : {
59 0 : seed ^= m_SizeHash(val) + 0x9e3779b9 + (seed << 6) + (seed >> 2);
60 0 : }
61 :
62 : private:
63 : std::hash<ssize_t> m_SizeHash;
64 : };
65 : }
66 :
67 : //////////////////////////////////////////////////////////////////////////
68 :
69 : template<typename T>
70 0 : T DeltaArray2D<T>::get(ssize_t x, ssize_t y)
71 : {
72 0 : typename Data::iterator it = m_Data.find(std::make_pair(x, y));
73 0 : if (it == m_Data.end())
74 0 : return getOld(x, y);
75 : else
76 0 : return it->second.second;
77 : }
78 :
79 : template<typename T>
80 0 : void DeltaArray2D<T>::set(ssize_t x, ssize_t y, const T& val)
81 : {
82 0 : typename Data::iterator it = m_Data.find(std::make_pair(x, y));
83 0 : if (it == m_Data.end())
84 0 : m_Data.insert(std::make_pair(std::make_pair(x, y), std::make_pair(getOld(x, y), val)));
85 : else
86 0 : it->second.second = val;
87 0 : setNew(x, y, val);
88 0 : }
89 :
90 : template <typename T>
91 0 : void DeltaArray2D<T>::OverlayWith(const DeltaArray2D<T>& overlayer)
92 : {
93 0 : for (typename Data::const_iterator it = overlayer.m_Data.begin(); it != overlayer.m_Data.end(); ++it)
94 : {
95 0 : typename Data::iterator it2 = m_Data.find(it->first);
96 0 : if (it2 == m_Data.end())
97 0 : m_Data.insert(*it);
98 : else
99 : {
100 : //ENSURE(it2->second.second == it->second.first);
101 0 : it2->second.second = it->second.second;
102 : }
103 : }
104 :
105 0 : }
106 :
107 : template <typename T>
108 0 : void DeltaArray2D<T>::Undo()
109 : {
110 0 : for (typename Data::iterator it = m_Data.begin(); it != m_Data.end(); ++it)
111 0 : setNew(it->first.first, it->first.second, it->second.first);
112 0 : }
113 :
114 : template <typename T>
115 0 : void DeltaArray2D<T>::Redo()
116 : {
117 0 : for (typename Data::iterator it = m_Data.begin(); it != m_Data.end(); ++it)
118 0 : setNew(it->first.first, it->first.second, it->second.second);
119 0 : }
120 :
121 : #endif // INCLUDED_DELTAARRAY
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