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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, 2011
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 <gecode/int/rel.hh>
35
36namespace Gecode { namespace Int { namespace NValues {
37
38 template<class VY>
39 forceinline
40 GqBool<VY>::GqBool(Home home, int status, ViewArray<BoolView>& x, VY y)
41 : BoolBase<VY>(home,status,x,y) {}
42
43 template<class VY>
44 forceinline
45 GqBool<VY>::GqBool(Space& home, GqBool<VY>& p)
46 : BoolBase<VY>(home,p) {}
47
48 template<class VY>
49 Actor*
50 GqBool<VY>::copy(Space& home) {
51 return new (home) GqBool<VY>(home,*this);
52 }
53
54 template<class VY>
55 inline ExecStatus
56 GqBool<VY>::post(Home home, ViewArray<BoolView>& x, VY y) {
57 if (x.size() == 0) {
58 GECODE_ME_CHECK(y.lq(home,0));
59 return ES_OK;
60 }
61
62 x.unique();
63
64 if (x.size() == 1) {
65 GECODE_ME_CHECK(y.lq(home,1));
66 return ES_OK;
67 }
68
69 GECODE_ME_CHECK(y.lq(home,2));
70
71 if (y.max() <= 1)
72 return ES_OK;
73
74 if (y.min() == 2) {
75 assert(y.assigned());
76 ViewArray<BoolView> xc(home,x);
77 return Rel::NaryNq<BoolView>::post(home,xc);
78 }
79
80 int n = x.size();
81 int status = 0;
82 for (int i=n; i--; )
83 if (x[i].zero()) {
84 if (status & VS_ONE)
85 return ES_OK;
86 x[i] = x[--n];
87 status |= VS_ZERO;
88 } else if (x[i].one()) {
89 if (status & VS_ZERO)
90 return ES_OK;
91 x[i] = x[--n];
92 status |= VS_ONE;
93 }
94
95 assert(status != (VS_ZERO | VS_ONE));
96 if (n == 0) {
97 assert(status != 0);
98 GECODE_ME_CHECK(y.lq(home,1));
99 return ES_OK;
100 }
101 x.size(n);
102
103 (void) new (home) GqBool<VY>(home,status,x,y);
104 return ES_OK;
105 }
106
107 template<class VY>
108 ExecStatus
109 GqBool<VY>::propagate(Space& home, const ModEventDelta&) {
110 if (status == (VS_ZERO | VS_ONE))
111 return home.ES_SUBSUMED(*this);
112
113 if (c.empty()) {
114 assert(status != 0);
115 GECODE_ME_CHECK(y.lq(home,1));
116 return home.ES_SUBSUMED(*this);
117 }
118
119 if (y.max() <= 1)
120 return home.ES_SUBSUMED(*this);
121
122 if (y.min() == 2) {
123 Advisors<ViewAdvisor<BoolView> > as(c);
124 assert(as());
125 ViewAdvisor<BoolView>& a(as.advisor());
126 ++as;
127 if (!as()) {
128 // Only a single view is left
129 if (status == VS_ZERO) {
130 GECODE_ME_CHECK(a.view().one(home));
131 } else if (status == VS_ONE) {
132 GECODE_ME_CHECK(a.view().zero(home));
133 } else {
134 return ES_FAILED;
135 }
136 return home.ES_SUBSUMED(*this);
137 }
138 }
139
140 return ES_FIX;
141 }
142
143}}}
144
145// STATISTICS: int-prop