compile-strings.h revision f4c12fce1ee58e670f9c3fce46c40296ba9ee8a2 
1
2// Licensed under the Apache License, Version 2.0 (the "License");
3// you may not use this file except in compliance with the License.
4// You may obtain a copy of the License at
5//
6//     http://www.apache.org/licenses/LICENSE-2.0
7//
8// Unless required by applicable law or agreed to in writing, software
9// distributed under the License is distributed on an "AS IS" BASIS,
10// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
11// See the License for the specific language governing permissions and
12// limitations under the License.
13//
14// Copyright 2005-2010 Google, Inc.
15// Authors: allauzen@google.com (Cyril Allauzen)
16//          ttai@google.com (Terry Tai)
17//          jpr@google.com (Jake Ratkiewicz)
18
19
20#ifndef FST_EXTENSIONS_FAR_COMPILE_STRINGS_H_
21#define FST_EXTENSIONS_FAR_COMPILE_STRINGS_H_
22
23#include <libgen.h>
24#include <string>
25#include <vector>
26using std::vector;
27
28#include <fst/extensions/far/far.h>
29#include <fst/string.h>
30
31namespace fst {
32
33// Construct a reader that provides FSTs from a file (stream) either on a
34// line-by-line basis or on a per-stream basis.  Note that the freshly
35// constructed reader is already set to the first input.
36//
37// Sample Usage:
38//   for (StringReader<Arc> reader(...); !reader.Done(); reader.Next()) {
39//     Fst *fst = reader.GetVectorFst();
40//   }
41template <class A>
42class StringReader {
43 public:
44  typedef A Arc;
45  typedef typename A::Label Label;
46  typedef typename A::Weight Weight;
47  typedef typename StringCompiler<A>::TokenType TokenType;
48
49  enum EntryType { LINE = 1, FILE = 2 };
50
51  StringReader(istream &istrm,
52               const string &source,
53               EntryType entry_type,
54               TokenType token_type,
55               bool allow_negative_labels,
56               const SymbolTable *syms = 0,
57               Label unknown_label = kNoStateId)
58      : nline_(0), strm_(istrm), source_(source), entry_type_(entry_type),
59        token_type_(token_type), done_(false),
60        compiler_(token_type, syms, unknown_label, allow_negative_labels) {
61    Next();  // Initialize the reader to the first input.
62  }
63
64  bool Done() {
65    return done_;
66  }
67
68  void Next() {
69    VLOG(1) << "Processing source " << source_ << " at line " << nline_;
70    if (!strm_) {                    // We're done if we have no more input.
71      done_ = true;
72      return;
73    }
74    if (entry_type_ == LINE) {
75      getline(strm_, content_);
76      ++nline_;
77    } else {
78      content_.clear();
79      string line;
80      while (getline(strm_, line)) {
81        ++nline_;
82        content_.append(line);
83        content_.append("\n");
84      }
85    }
86    if (!strm_ && content_.empty())  // We're also done if we read off all the
87      done_ = true;                  // whitespace at the end of a file.
88  }
89
90  VectorFst<A> *GetVectorFst() {
91    VectorFst<A> *fst = new VectorFst<A>;
92    if (compiler_(content_, fst)) {
93      return fst;
94    } else {
95      delete fst;
96      return NULL;
97    }
98  }
99
100  CompactFst<A, StringCompactor<A> > *GetCompactFst() {
101    CompactFst<A, StringCompactor<A> > *fst =
102        new CompactFst<A, StringCompactor<A> >;
103    if (compiler_(content_, fst)) {
104      return fst;
105    } else {
106      delete fst;
107      return NULL;
108    }
109  }
110
111 private:
112  size_t nline_;
113  istream &strm_;
114  string source_;
115  EntryType entry_type_;
116  TokenType token_type_;
117  bool done_;
118  StringCompiler<A> compiler_;
119  string content_;  // The actual content of the input stream's next FST.
120
121  DISALLOW_COPY_AND_ASSIGN(StringReader);
122};
123
124// Compute the minimal length required to encode each line number as a decimal
125// number.
126int KeySize(const char *filename);
127
128template <class Arc>
129void FarCompileStrings(const vector<string> &in_fnames,
130                       const string &out_fname,
131                       const string &fst_type,
132                       const FarType &far_type,
133                       int32 generate_keys,
134                       FarEntryType fet,
135                       FarTokenType tt,
136                       const string &symbols_fname,
137                       const string &unknown_symbol,
138                       bool allow_negative_labels,
139                       bool file_list_input,
140                       const string &key_prefix,
141                       const string &key_suffix) {
142  typename StringReader<Arc>::EntryType entry_type;
143  if (fet == FET_LINE) {
144    entry_type = StringReader<Arc>::LINE;
145  } else if (fet == FET_FILE) {
146    entry_type = StringReader<Arc>::FILE;
147  } else {
148    FSTERROR() << "FarCompileStrings: unknown entry type";
149    return;
150  }
151
152  typename StringCompiler<Arc>::TokenType token_type;
153  if (tt == FTT_SYMBOL) {
154    token_type = StringCompiler<Arc>::SYMBOL;
155  } else if (tt == FTT_BYTE) {
156    token_type = StringCompiler<Arc>::BYTE;
157  } else if (tt == FTT_UTF8) {
158    token_type = StringCompiler<Arc>::UTF8;
159  } else {
160    FSTERROR() << "FarCompileStrings: unknown token type";
161    return;
162  }
163
164  bool compact;
165  if (fst_type.empty() || (fst_type == "vector")) {
166    compact = false;
167  } else if (fst_type == "compact") {
168    compact = true;
169  } else {
170    FSTERROR() << "FarCompileStrings: unknown fst type: "
171               << fst_type;
172    return;
173  }
174
175  const SymbolTable *syms = 0;
176  typename Arc::Label unknown_label = kNoLabel;
177  if (!symbols_fname.empty()) {
178    syms = SymbolTable::ReadText(symbols_fname,
179                                 allow_negative_labels);
180    if (!syms) {
181      FSTERROR() << "FarCompileStrings: error reading symbol table: "
182                 << symbols_fname;
183      return;
184    }
185    if (!unknown_symbol.empty()) {
186      unknown_label = syms->Find(unknown_symbol);
187      if (unknown_label == kNoLabel) {
188        FSTERROR() << "FarCompileStrings: unknown label \"" << unknown_label
189                   << "\" missing from symbol table: " << symbols_fname;
190        return;
191      }
192    }
193  }
194
195  FarWriter<Arc> *far_writer =
196      FarWriter<Arc>::Create(out_fname, far_type);
197  if (!far_writer) return;
198
199  vector<string> inputs;
200  if (file_list_input) {
201    for (int i = 1; i < in_fnames.size(); ++i) {
202      ifstream istrm(in_fnames[i].c_str());
203      string str;
204      while (getline(istrm, str))
205        inputs.push_back(str);
206    }
207  } else {
208    inputs = in_fnames;
209  }
210
211  for (int i = 0, n = 0; i < inputs.size(); ++i) {
212    int key_size = generate_keys ? generate_keys :
213        (entry_type == StringReader<Arc>::FILE ? 1 :
214         KeySize(inputs[i].c_str()));
215    ifstream istrm(inputs[i].c_str());
216
217    for (StringReader<Arc> reader(
218             istrm, inputs[i], entry_type, token_type,
219             allow_negative_labels, syms, unknown_label);
220         !reader.Done();
221         reader.Next()) {
222      ++n;
223      const Fst<Arc> *fst;
224      if (compact)
225        fst = reader.GetCompactFst();
226      else
227        fst = reader.GetVectorFst();
228      if (!fst) {
229        FSTERROR() << "FarCompileStrings: compiling string number " << n
230                   << " in file " << inputs[i] << " failed with token_type = "
231                   << (tt == FTT_BYTE ? "byte" :
232                       (tt == FTT_UTF8 ? "utf8" :
233                        (tt == FTT_SYMBOL ? "symbol" : "unknown")))
234                   << " and entry_type = "
235                   << (fet == FET_LINE ? "line" :
236                       (fet == FET_FILE ? "file" : "unknown"));
237        delete far_writer;
238        delete syms;
239        return;
240      }
241      ostringstream keybuf;
242      keybuf.width(key_size);
243      keybuf.fill('0');
244      keybuf << n;
245      string key;
246      if (generate_keys > 0) {
247        key = keybuf.str();
248      } else {
249        char* filename = new char[inputs[i].size() + 1];
250        strcpy(filename, inputs[i].c_str());
251        key = basename(filename);
252        if (entry_type != StringReader<Arc>::FILE) {
253          key += "-";
254          key += keybuf.str();
255        }
256        delete[] filename;
257      }
258      far_writer->Add(key_prefix + key + key_suffix, *fst);
259      delete fst;
260    }
261    if (generate_keys == 0)
262      n = 0;
263  }
264
265  delete far_writer;
266}
267
268}  // namespace fst
269
270
271#endif  // FST_EXTENSIONS_FAR_COMPILE_STRINGS_H_
272