1 /* -*- mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*- */
2 /*
3  *  Main authors:
4  *     Christian Schulte <schulte@gecode.org>
5  *
6  *  Copyright:
7  *     Christian Schulte, 2017
8  *
9  *  This file is part of Gecode, the generic constraint
10  *  development environment:
11  *     http://www.gecode.org
12  *
13  *  Permission is hereby granted, free of charge, to any person obtaining
14  *  a copy of this software and associated documentation files (the
15  *  "Software"), to deal in the Software without restriction, including
16  *  without limitation the rights to use, copy, modify, merge, publish,
17  *  distribute, sublicense, and/or sell copies of the Software, and to
18  *  permit persons to whom the Software is furnished to do so, subject to
19  *  the following conditions:
20  *
21  *  The above copyright notice and this permission notice shall be
22  *  included in all copies or substantial portions of the Software.
23  *
24  *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
25  *  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
26  *  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
27  *  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
28  *  LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
29  *  OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
30  *  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
31  *
32  */
33 
34 #include <functional>
35 
36 namespace Gecode {
37 
38   /// Function type for branch filter functions
39   template<class Var>
40   using BranchFilter = std::function<bool(const Space& home,
41                                           Var x, int i)>;
42 
43   /// Class storing a branch filter function
44   template<class View>
45   class BrancherFilter {
46   public:
47     /// The corresponding variable type
48     typedef typename View::VarType Var;
49   protected:
50     SharedData<BranchFilter<Var>> f;
51   public:
52     /// Initialize
53     BrancherFilter(BranchFilter<Var> bf);
54     /// Initialize during cloning
55     BrancherFilter(BrancherFilter& bf);
56     /// Whether filtering is enabled
57     operator bool(void) const;
58     /// Invoke filter function
59     bool operator ()(const Space& home, View x, int i) const;
60     /// Whether dispose must always be called (that is, notice is needed)
61     bool notice(void) const;
62     /// Delete object
63     void dispose(Space& home);
64   };
65 
66   /// Class withot a branch filter function
67   template<class View>
68   class BrancherNoFilter {
69   public:
70     /// The corresponding variable type
71     typedef typename View::VarType Var;
72   public:
73     /// Initialize
74     BrancherNoFilter(BranchFilter<Var> bf);
75     /// Initialize during cloning
76     BrancherNoFilter(BrancherNoFilter& bf);
77     /// Whether filtering is enabled
78     operator bool(void) const;
79     /// Invoke filter function
80     bool operator ()(const Space& home, View x, int i) const;
81     /// Whether dispose must always be called (that is, notice is needed)
82     bool notice(void) const;
83     /// Delete object
84     void dispose(Space& home);
85   };
86 
87 
88   template<class View>
89   forceinline
BrancherFilter(BranchFilter<Var> bf)90   BrancherFilter<View>::BrancherFilter(BranchFilter<Var> bf) : f(bf) {
91     if (!bf)
92       throw Gecode::InvalidFunction("BrancherFilter::BrancherFilter");
93   }
94 
95   template<class View>
96   forceinline
BrancherFilter(BrancherFilter<View> & bf)97   BrancherFilter<View>::BrancherFilter(BrancherFilter<View>& bf)
98     : f(bf.f) {
99   }
100 
101   template<class View>
102   forceinline
operator bool(void) const103   BrancherFilter<View>::operator bool(void) const {
104     return true;
105   }
106 
107   template<class View>
108   forceinline bool
operator ()(const Space & home,View x,int i) const109   BrancherFilter<View>::operator ()(const Space& home, View x, int i) const {
110     GECODE_VALID_FUNCTION(f());
111     Var xv(x.varimp());
112     return f()(home,xv,i);
113   }
114 
115   template<class View>
116   forceinline bool
notice(void) const117   BrancherFilter<View>::notice(void) const {
118     return true;
119   }
120 
121   template<class View>
122   forceinline void
dispose(Space &)123   BrancherFilter<View>::dispose(Space&) {
124     f.~SharedData<BranchFilter<Var>>();
125   }
126 
127 
128   template<class View>
129   forceinline
BrancherNoFilter(BranchFilter<Var> bf)130   BrancherNoFilter<View>::BrancherNoFilter(BranchFilter<Var> bf) {
131     assert(!bf);
132     (void) bf;
133   }
134 
135   template<class View>
136   forceinline
BrancherNoFilter(BrancherNoFilter<View> &)137   BrancherNoFilter<View>::BrancherNoFilter(BrancherNoFilter<View>&) {}
138 
139   template<class View>
140   forceinline
operator bool(void) const141   BrancherNoFilter<View>::operator bool(void) const {
142     return false;
143   }
144 
145   template<class View>
146   forceinline bool
operator ()(const Space &,View,int) const147   BrancherNoFilter<View>::operator ()(const Space&, View, int) const {
148     return true;
149   }
150   template<class View>
151   forceinline bool
notice(void) const152   BrancherNoFilter<View>::notice(void) const {
153     return false;
154   }
155 
156   template<class View>
157   forceinline void
dispose(Space &)158   BrancherNoFilter<View>::dispose(Space&) {
159   }
160 
161 }
162 
163 // STATISTICS: kernel-branch
164