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
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
|
// intersect.h
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// Copyright 2005-2010 Google, Inc.
// Author: riley@google.com (Michael Riley)
//
// \file
// Class to compute the intersection of two FSAs
#ifndef FST_LIB_INTERSECT_H__
#define FST_LIB_INTERSECT_H__
#include <algorithm>
#include <vector>
using std::vector;
#include <fst/cache.h>
#include <fst/compose.h>
namespace fst {
template <class A,
class M = Matcher<Fst<A> >,
class F = SequenceComposeFilter<M>,
class T = GenericComposeStateTable<A, typename F::FilterState> >
struct IntersectFstOptions : public ComposeFstOptions<A, M, F, T> {
explicit IntersectFstOptions(const CacheOptions &opts,
M *mat1 = 0, M *mat2 = 0,
F *filt = 0, T *sttable= 0)
: ComposeFstOptions<A, M, F, T>(opts, mat1, mat2, filt, sttable) { }
IntersectFstOptions() {}
};
// Computes the intersection (Hadamard product) of two FSAs. This
// version is a delayed Fst. Only strings that are in both automata
// are retained in the result.
//
// The two arguments must be acceptors. One of the arguments must be
// label-sorted.
//
// Complexity: same as ComposeFst.
//
// Caveats: same as ComposeFst.
template <class A>
class IntersectFst : public ComposeFst<A> {
public:
using ComposeFst<A>::CreateBase;
using ComposeFst<A>::CreateBase1;
using ComposeFst<A>::Properties;
using ImplToFst< ComposeFstImplBase<A> >::GetImpl;
using ImplToFst< ComposeFstImplBase<A> >::SetImpl;
typedef A Arc;
typedef typename A::Weight Weight;
typedef typename A::StateId StateId;
IntersectFst(const Fst<A> &fst1, const Fst<A> &fst2,
const CacheOptions opts = CacheOptions()) {
bool acceptors = fst1.Properties(kAcceptor, true) &&
fst2.Properties(kAcceptor, true);
SetImpl(CreateBase(fst1, fst2, opts));
if (!acceptors) {
FSTERROR() << "IntersectFst: input FSTs are not acceptors";
GetImpl()->SetProperties(kError);
}
}
template <class M, class F, class T>
IntersectFst(const Fst<A> &fst1, const Fst<A> &fst2,
const IntersectFstOptions<A, M, F, T> &opts) {
bool acceptors = fst1.Properties(kAcceptor, true) &&
fst2.Properties(kAcceptor, true);
SetImpl(CreateBase1(fst1, fst2, opts));
if (!acceptors) {
FSTERROR() << "IntersectFst: input FSTs are not acceptors";
GetImpl()->SetProperties(kError);
}
}
// See Fst<>::Copy() for doc.
IntersectFst(const IntersectFst<A> &fst, bool safe = false) :
ComposeFst<A>(fst, safe) {}
// Get a copy of this IntersectFst. See Fst<>::Copy() for further doc.
virtual IntersectFst<A> *Copy(bool safe = false) const {
return new IntersectFst<A>(*this, safe);
}
};
// Specialization for IntersectFst.
template <class A>
class StateIterator< IntersectFst<A> >
: public StateIterator< ComposeFst<A> > {
public:
explicit StateIterator(const IntersectFst<A> &fst)
: StateIterator< ComposeFst<A> >(fst) {}
};
// Specialization for IntersectFst.
template <class A>
class ArcIterator< IntersectFst<A> >
: public ArcIterator< ComposeFst<A> > {
public:
typedef typename A::StateId StateId;
ArcIterator(const IntersectFst<A> &fst, StateId s)
: ArcIterator< ComposeFst<A> >(fst, s) {}
};
// Useful alias when using StdArc.
typedef IntersectFst<StdArc> StdIntersectFst;
typedef ComposeOptions IntersectOptions;
// Computes the intersection (Hadamard product) of two FSAs. This
// version writes the intersection to an output MurableFst. Only
// strings that are in both automata are retained in the result.
//
// The two arguments must be acceptors. One of the arguments must be
// label-sorted.
//
// Complexity: same as Compose.
//
// Caveats: same as Compose.
template<class Arc>
void Intersect(const Fst<Arc> &ifst1, const Fst<Arc> &ifst2,
MutableFst<Arc> *ofst,
const IntersectOptions &opts = IntersectOptions()) {
typedef Matcher< Fst<Arc> > M;
if (opts.filter_type == AUTO_FILTER) {
CacheOptions nopts;
nopts.gc_limit = 0; // Cache only the last state for fastest copy.
*ofst = IntersectFst<Arc>(ifst1, ifst2, nopts);
} else if (opts.filter_type == SEQUENCE_FILTER) {
IntersectFstOptions<Arc> iopts;
iopts.gc_limit = 0; // Cache only the last state for fastest copy.
*ofst = IntersectFst<Arc>(ifst1, ifst2, iopts);
} else if (opts.filter_type == ALT_SEQUENCE_FILTER) {
IntersectFstOptions<Arc, M, AltSequenceComposeFilter<M> > iopts;
iopts.gc_limit = 0; // Cache only the last state for fastest copy.
*ofst = IntersectFst<Arc>(ifst1, ifst2, iopts);
} else if (opts.filter_type == MATCH_FILTER) {
IntersectFstOptions<Arc, M, MatchComposeFilter<M> > iopts;
iopts.gc_limit = 0; // Cache only the last state for fastest copy.
*ofst = IntersectFst<Arc>(ifst1, ifst2, iopts);
}
if (opts.connect)
Connect(ofst);
}
} // namespace fst
#endif // FST_LIB_INTERSECT_H__
|