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dekker.one
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, 2006
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
34namespace Gecode { namespace Int { namespace Count {
35
36 template<class VX, class VY>
37 forceinline
38 EqInt<VX,VY>::EqInt(Home home, ViewArray<VX>& x, int n_s, VY y, int c)
39 : IntBase<VX,VY>(home,x,n_s,y,c) {}
40
41 template<class VX, class VY>
42 ExecStatus
43 EqInt<VX,VY>::post(Home home, ViewArray<VX>& x, VY y, int c) {
44 // Eliminate decided views
45 int n_x = x.size();
46 for (int i=n_x; i--; )
47 switch (holds(x[i],y)) {
48 case RT_FALSE:
49 x[i] = x[--n_x]; break;
50 case RT_TRUE:
51 x[i] = x[--n_x]; c--; break;
52 case RT_MAYBE:
53 break;
54 default:
55 GECODE_NEVER;
56 }
57 x.size(n_x);
58 // RHS too small or too large
59 if ((c < 0) || (c > n_x))
60 return ES_FAILED;
61 // All views must be different
62 if (c == 0)
63 return post_false(home,x,y);
64 // All views must be equal
65 if (c == n_x)
66 return post_true(home,x,y);
67 // Compute how many subscriptions must be created
68 int n_s = std::max(c,n_x-c)+1;
69 assert(n_s <= n_x);
70 (void) new (home) EqInt<VX,VY>(home,x,n_s,y,c);
71 return ES_OK;
72 }
73
74 template<class VX, class VY>
75 forceinline
76 EqInt<VX,VY>::EqInt(Space& home, EqInt<VX,VY>& p)
77 : IntBase<VX,VY>(home,p) {}
78
79 template<class VX, class VY>
80 Actor*
81 EqInt<VX,VY>::copy(Space& home) {
82 return new (home) EqInt<VX,VY>(home,*this);
83 }
84
85 template<class VX, class VY>
86 ExecStatus
87 EqInt<VX,VY>::propagate(Space& home, const ModEventDelta&) {
88 // Eliminate decided views from subscribed views
89 int n_x = x.size();
90 for (int i=n_s; i--; )
91 switch (holds(x[i],y)) {
92 case RT_FALSE:
93 x[i].cancel(home,*this,PC_INT_DOM);
94 x[i]=x[--n_s]; x[n_s]=x[--n_x];
95 break;
96 case RT_TRUE:
97 x[i].cancel(home,*this,PC_INT_DOM);
98 x[i]=x[--n_s]; x[n_s]=x[--n_x]; c--;
99 break;
100 case RT_MAYBE:
101 break;
102 default:
103 GECODE_NEVER;
104 }
105 x.size(n_x);
106 if ((c < 0) || (c > n_x))
107 return ES_FAILED;
108 // Eliminate decided views from unsubscribed views
109 for (int i=n_x; i-- > n_s; )
110 switch (holds(x[i],y)) {
111 case RT_FALSE: x[i]=x[--n_x]; break;
112 case RT_TRUE: x[i]=x[--n_x]; c--; break;
113 case RT_MAYBE: break;
114 default: GECODE_NEVER;
115 }
116 x.size(n_x);
117 if ((c < 0) || (c > n_x))
118 return ES_FAILED;
119 if (c == 0) {
120 // All views must be different
121 GECODE_ES_CHECK(post_false(home,x,y));
122 return home.ES_SUBSUMED(*this);
123 }
124 if (c == n_x) {
125 // All views must be equal
126 GECODE_ES_CHECK(post_true(home,x,y));
127 return home.ES_SUBSUMED(*this);
128 }
129 int m = std::max(c,n_x-c)+1;
130 assert(m <= n_x);
131 // Now, there must be new subscriptions from x[n_s] up to x[m-1]
132 while (n_s < m)
133 x[n_s++].subscribe(home,*this,PC_INT_DOM,false);
134 return ES_FIX;
135 }
136
137}}}
138
139// STATISTICS: int-prop