1 files changed, 151 insertions, 0 deletions
diff --git a/src/include/fst/lexicographic-weight.h b/src/include/fst/lexicographic-weight.h
new file mode 100644
index 0000000..4b55c50
--- /dev/null
+++ b/src/include/fst/lexicographic-weight.h
@@ -0,0 +1,151 @@
+// lexicographic-weight.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: rws@google.com (Richard Sproat)
+//
+// \file
+// Lexicographic weight set and associated semiring operation definitions.
+//
+// A lexicographic weight is a sequence of weights, each of which must have the
+// path property and Times() must be (strongly) cancellative
+// (for all a,b,c != Zero(): Times(c, a) = Times(c, b) => a = b,
+// Times(a, c) = Times(b, c) => a = b).
+// The + operation on two weights a and b is the lexicographically
+// prior of a and b.
+
+#ifndef FST_LIB_LEXICOGRAPHIC_WEIGHT_H__
+#define FST_LIB_LEXICOGRAPHIC_WEIGHT_H__
+
+#include <string>
+
+#include <fst/pair-weight.h>
+#include <fst/weight.h>
+
+
+namespace fst {
+
+template<class W1, class W2>
+class LexicographicWeight : public PairWeight<W1, W2> {
+ public:
+  using PairWeight<W1, W2>::Value1;
+  using PairWeight<W1, W2>::Value2;
+  using PairWeight<W1, W2>::SetValue1;
+  using PairWeight<W1, W2>::SetValue2;
+  using PairWeight<W1, W2>::Zero;
+  using PairWeight<W1, W2>::One;
+  using PairWeight<W1, W2>::NoWeight;
+  using PairWeight<W1, W2>::Quantize;
+  using PairWeight<W1, W2>::Reverse;
+
+  typedef LexicographicWeight<typename W1::ReverseWeight,
+                              typename W2::ReverseWeight>
+  ReverseWeight;
+
+  LexicographicWeight() {}
+
+  LexicographicWeight(const PairWeight<W1, W2>& w)
+      : PairWeight<W1, W2>(w) {}
+
+  LexicographicWeight(W1 w1, W2 w2) : PairWeight<W1, W2>(w1, w2) {
+    uint64 props = kPath;
+    if ((W1::Properties() & props) != props) {
+      FSTERROR() << "LexicographicWeight must "
+                 << "have the path property: " << W1::Type();
+      SetValue1(W1::NoWeight());
+    }
+    if ((W2::Properties() & props) != props) {
+      FSTERROR() << "LexicographicWeight must "
+                 << "have the path property: " << W2::Type();
+      SetValue2(W2::NoWeight());
+    }
+  }
+
+  static const LexicographicWeight<W1, W2> &Zero() {
+    static const LexicographicWeight<W1, W2> zero(PairWeight<W1, W2>::Zero());
+    return zero;
+  }
+
+  static const LexicographicWeight<W1, W2> &One() {
+    static const LexicographicWeight<W1, W2> one(PairWeight<W1, W2>::One());
+    return one;
+  }
+
+  static const LexicographicWeight<W1, W2> &NoWeight() {
+    static const LexicographicWeight<W1, W2> no_weight(
+        PairWeight<W1, W2>::NoWeight());
+    return no_weight;
+  }
+
+  static const string &Type() {
+    static const string type = W1::Type() + "_LT_" + W2::Type();
+    return type;
+  }
+
+  bool Member() const {
+    if (!Value1().Member() || !Value2().Member()) return false;
+    // Lexicographic weights cannot mix zeroes and non-zeroes.
+    if (Value1() == W1::Zero() && Value2() == W2::Zero()) return true;
+    if (Value1() != W1::Zero() && Value2() != W2::Zero()) return true;
+    return false;
+  }
+
+  LexicographicWeight<W1, W2> Quantize(float delta = kDelta) const {
+    return PairWeight<W1, W2>::Quantize();
+  }
+
+  ReverseWeight Reverse() const {
+    return PairWeight<W1, W2>::Reverse();
+  }
+
+  static uint64 Properties() {
+    uint64 props1 = W1::Properties();
+    uint64 props2 = W2::Properties();
+    return props1 & props2 & (kLeftSemiring | kRightSemiring | kPath |
+                              kIdempotent | kCommutative);
+  }
+};
+
+template <class W1, class W2>
+inline LexicographicWeight<W1, W2> Plus(const LexicographicWeight<W1, W2> &w,
+                                        const LexicographicWeight<W1, W2> &v) {
+  if (!w.Member() || !v.Member())
+    return LexicographicWeight<W1, W2>::NoWeight();
+  NaturalLess<W1> less1;
+  NaturalLess<W2> less2;
+  if (less1(w.Value1(), v.Value1())) return w;
+  if (less1(v.Value1(), w.Value1())) return v;
+  if (less2(w.Value2(), v.Value2())) return w;
+  if (less2(v.Value2(), w.Value2())) return v;
+  return w;
+}
+
+template <class W1, class W2>
+inline LexicographicWeight<W1, W2> Times(const LexicographicWeight<W1, W2> &w,
+                                         const LexicographicWeight<W1, W2> &v) {
+  return LexicographicWeight<W1, W2>(Times(w.Value1(), v.Value1()),
+                                     Times(w.Value2(), v.Value2()));
+}
+
+template <class W1, class W2>
+inline LexicographicWeight<W1, W2> Divide(const LexicographicWeight<W1, W2> &w,
+                                          const LexicographicWeight<W1, W2> &v,
+                                          DivideType typ = DIVIDE_ANY) {
+  return LexicographicWeight<W1, W2>(Divide(w.Value1(), v.Value1(), typ),
+                                     Divide(w.Value2(), v.Value2(), typ));
+}
+
+}  // namespace fst
+
+#endif  // FST_LIB_LEXICOGRAPHIC_WEIGHT_H__