1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
|
/********************* */
/*! \file skolem_cache.cpp
** \verbatim
** Top contributors (to current version):
** Andrew Reynolds
** This file is part of the CVC4 project.
** Copyright (c) 2009-2018 by the authors listed in the file AUTHORS
** in the top-level source directory) and their institutional affiliations.
** All rights reserved. See the file COPYING in the top-level source
** directory for licensing information.\endverbatim
**
** \brief Implementation of a cache of skolems for theory of strings.
**/
#include "theory/strings/skolem_cache.h"
#include "options/strings_options.h"
#include "theory/rewriter.h"
#include "theory/strings/theory_strings_rewriter.h"
#include "util/rational.h"
namespace CVC4 {
namespace theory {
namespace strings {
SkolemCache::SkolemCache()
{
NodeManager* nm = NodeManager::currentNM();
d_strType = nm->stringType();
d_zero = nm->mkConst(Rational(0));
}
Node SkolemCache::mkSkolemCached(Node a, Node b, SkolemId id, const char* c)
{
return mkTypedSkolemCached(d_strType, a, b, id, c);
}
Node SkolemCache::mkSkolemCached(Node a, SkolemId id, const char* c)
{
return mkSkolemCached(a, Node::null(), id, c);
}
Node SkolemCache::mkTypedSkolemCached(
TypeNode tn, Node a, Node b, SkolemId id, const char* c)
{
if (!options::stringsCacheSkolems())
{
Node n = NodeManager::currentNM()->mkSkolem(c, tn, "string skolem");
d_allSkolems.insert(n);
return n;
}
a = a.isNull() ? a : Rewriter::rewrite(a);
b = b.isNull() ? b : Rewriter::rewrite(b);
if (tn == d_strType)
{
std::tie(id, a, b) = normalizeStringSkolem(id, a, b);
}
std::map<SkolemId, Node>::iterator it = d_skolemCache[a][b].find(id);
if (it == d_skolemCache[a][b].end())
{
Node sk = mkTypedSkolem(tn, c);
d_skolemCache[a][b][id] = sk;
return sk;
}
return it->second;
}
Node SkolemCache::mkTypedSkolemCached(TypeNode tn,
Node a,
SkolemId id,
const char* c)
{
return mkTypedSkolemCached(tn, a, Node::null(), id, c);
}
Node SkolemCache::mkSkolem(const char* c)
{
return mkTypedSkolem(d_strType, c);
}
Node SkolemCache::mkTypedSkolem(TypeNode tn, const char* c)
{
Node n = NodeManager::currentNM()->mkSkolem(c, tn, "string skolem");
d_allSkolems.insert(n);
return n;
}
bool SkolemCache::isSkolem(Node n) const
{
return d_allSkolems.find(n) != d_allSkolems.end();
}
std::tuple<SkolemCache::SkolemId, Node, Node>
SkolemCache::normalizeStringSkolem(SkolemId id, Node a, Node b)
{
if (!options::stringsNormalizeSkolems())
{
return std::make_tuple(id, a, b);
}
Trace("skolem-cache") << "normalizeStringSkolem start: (" << id << ", " << a
<< ", " << b << ")" << std::endl;
// SK_PURIFY(str.substr x 0 (str.indexof x y 0)) ---> SK_FIRST_CTN_PRE(x, y)
if (id == SK_PURIFY && a.getKind() == kind::STRING_SUBSTR)
{
Node s = a[0];
Node n = a[1];
Node m = a[2];
if (m.getKind() == kind::STRING_STRIDOF && m[0] == s)
{
if (n == d_zero && m[2] == d_zero)
{
id = SK_FIRST_CTN_PRE;
a = m[0];
b = m[1];
}
}
}
if (id == SK_FIRST_CTN_PRE)
{
// SK_FIRST_CTN_PRE((str.substr x 0 n), y) ---> SK_FIRST_CTN_PRE(x, y)
while (a.getKind() == kind::STRING_SUBSTR && a[1] == d_zero)
{
a = a[0];
}
}
Trace("skolem-cache") << "normalizeStringSkolem end: (" << id << ", " << a
<< ", " << b << ")" << std::endl;
return std::make_tuple(id, a, b);
}
} // namespace strings
} // namespace theory
} // namespace CVC4
|
