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
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
|
// Copyright 2016 Google Inc.
//
// 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.!
#ifndef SENTENCEPIECE_PROCESSOR_H_
#define SENTENCEPIECE_PROCESSOR_H_
#include <cstring>
#include <memory>
#include <string>
#include <utility>
#include <vector>
#if defined(_USE_INTERNAL_STRING_VIEW)
#include "third_party/absl/strings/string_view.h"
#elif defined(_USE_TF_STRING_VIEW)
#include "absl/strings/string_view.h"
#else
// Minimum absl::string_view class that is used only for
// the argument of public APIs.
namespace absl {
class string_view {
public:
string_view() : ptr_(nullptr), length_(0) {}
string_view(const std::string &str) : ptr_(str.data()), length_(str.size()) {}
string_view(const char *str) : ptr_(str), length_(std::strlen(str)) {}
string_view(const char *data, size_t len) : ptr_(data), length_(len) {}
const char *data() const { return ptr_; }
size_t size() const { return length_; }
private:
const char *ptr_ = nullptr;
size_t length_ = 0;
};
} // namespace absl
#endif
namespace sentencepiece {
#ifndef SWIG
using EncodeResult = std::vector<std::pair<absl::string_view, int>>;
#endif // SWIG
namespace util {
enum class StatusCode : int {
kOk = 0,
kCancelled = 1,
kUnknown = 2,
kInvalidArgument = 3,
kDeadlineExceeded = 4,
kNotFound = 5,
kAlreadyExists = 6,
kPermissionDenied = 7,
kResourceExhausted = 8,
kFailedPrecondition = 9,
kAborted = 10,
kOutOfRange = 11,
kUnimplemented = 12,
kInternal = 13,
kUnavailable = 14,
kDataLoss = 15,
kUnauthenticated = 16,
};
class Status {
public:
Status();
~Status();
Status(StatusCode code, const char *error_message);
Status(StatusCode code, const std::string &error_message);
Status(const Status &s);
void operator=(const Status &s);
bool operator==(const Status &s) const;
bool operator!=(const Status &s) const;
inline bool ok() const { return rep_ == nullptr; }
void set_error_message(const char *str);
const char *error_message() const;
const char *message() const { return error_message(); }
StatusCode code() const;
std::string ToString() const;
void IgnoreError();
private:
struct Rep;
std::unique_ptr<Rep> rep_;
};
} // namespace util
// SentencePieceProcessor:
// Simple and language independent tokenizer and de-tokenizer for
// Neural Network Machine Translation.
//
// SentencePieceProcessor provides Encode() and Decode() methods,
// which correspond to tokenization and de-tokenization respectively.
//
// - Encode:
// Given a raw source sentence, encode it into a sequence
// of pieces or vocabulary ids.
//
// - Decode:
// Given a sequence of pieces or vocabulary ids, decode it
// into a de-tokenized raw sentence.
//
// SentencePieceProcessor provides a lossless data conversion
// that allows the original raw sentence to be perfectly reconstructed
// from the encoded data, i.e., Decode(Encode(input)) == input.
// This characteristics is useful, as we can make the de-tokenization
// completely language independent.
//
// Usage:
// SentencePieceProcessor sp;
// sp.Load("//path/to/model");
//
// vector<string> sps;
// sp.Encode("hello world.", &sps);
//
// vector<int> ids;
// sp.Encode("hello world.", &ids);
//
// string detok;
// sp.Decode(sps, &detok);
// CHECK_EQ("hello world.", detok);
//
// sp.Decode(ids, &detok);
// CHECK_EQ("hello world.", detok);
//
// We can also use SentencePieceText which manages the byte-offsets
// between user input (output) and internal sentence pieces.
//
// SentencePieceText spt;
// sp.Encode("hello world.", &spt);
// // Emits the byte range of each piece.
// for (const auto &piece : spt.pieces()) {
// LOG(INFO) << piece.begin() << " " << piece.end();
// }
//
// sp.Decode({0, 1, 2, 3..}, &spt);
// for (const auto &piece : spt.pieces()) {
// LOG(INFO) << piece.begin() << " " << piece.end();
// }
//
class NBestSentencePieceText;
class ModelInterface;
class SentencePieceText;
class ModelProto;
namespace normalizer {
class Normalizer;
} // namespace normalizer
// Defines the multiple versions of encoder within each model. Currently only
// the Unigram model has an optimized encoder.
enum class EncoderVersion {
kOptimized, // The optimized encoder (default).
kOriginal // The original encoder (user may choose to fall back to this
// just in case).
};
namespace util {
// Redefine std::string for serialized_proto interface as Python's string is
// a Unicode string. We can enforce the return value to be raw byte sequence
// with SWIG's typemap.
using bytes = std::string;
} // namespace util
class SentencePieceProcessor {
public:
SentencePieceProcessor();
virtual ~SentencePieceProcessor();
// Loads model from `filename`.
// Returns false if `filename` cannot be loaded.
virtual util::Status Load(absl::string_view filename);
// Loads model from `filename`.
// Crash if `filename` cannot be loaded.
virtual void LoadOrDie(absl::string_view filename);
// Loads model from `model_proto`.
// `model_proto` is copied.
virtual util::Status Load(const ModelProto &model_proto);
// Loads model from `model_proto`.
// `model_proto` is moved.
virtual util::Status Load(std::unique_ptr<ModelProto> model_proto);
// Loads model from `serialized`, which is a string-serialized model proto.
// Useful to load the model from a platform independent blob object.
virtual util::Status LoadFromSerializedProto(absl::string_view serialized);
// Returns the status. Encode/Decode methods are valid when status is OK.
virtual util::Status status() const;
// Sets encode extra_option sequence.
virtual util::Status SetEncodeExtraOptions(absl::string_view extra_option);
// Sets decode extra_option sequence.
virtual util::Status SetDecodeExtraOptions(absl::string_view extra_option);
//////////////////////////////////////////////////////////////
// Vocabulary restriction.
// Background:
// https://github.com/rsennrich/subword-nmt#best-practice-advice-for-byte-pair-encoding-in-nmt
// Restricts the vocabulary set.
// The input sentences are encoded into the tokens in `valid_vocab`.
virtual util::Status SetVocabulary(
const std::vector<std::string> &valid_vocab);
// Reverts the vocabulary restriction.
virtual util::Status ResetVocabulary();
// Loads the valid vocabulary set from `filename` in TSV format.
// Format: <token> <tab> <freq>.
// Any token with frequency < threshold will be treated as OOV.
virtual util::Status LoadVocabulary(absl::string_view filename,
int threshold);
//////////////////////////////////////////////////////////////
// Simple API.
//
// Given a UTF8 input, encodes it into a sequence of sentence pieces.
virtual util::Status Encode(absl::string_view input,
std::vector<std::string> *pieces) const;
// Given a UTF8 input, encodes it into a sequence of ids.
virtual util::Status Encode(absl::string_view input,
std::vector<int> *ids) const;
// Given a sequence of pieces, decodes it into a detokenized output.
virtual util::Status Decode(const std::vector<std::string> &pieces,
std::string *detokenized) const;
// Given a sequence of ids, decodes it into a detokenized output.
virtual util::Status Decode(const std::vector<int> &ids,
std::string *detokenized) const;
// Sets the encoder version. Normally users do not need to call this function.
// But they can call this fucntion just in case if they want to fall back to
// the original encoder.
virtual util::Status SetEncoderVersion(EncoderVersion encoder_version);
// Returns the current encoder version in use.
virtual EncoderVersion GetEncoderVersion() const;
//////////////////////////////////////////////////////////////
// NBest API.
// Same as Encode, but returns nbest results.
virtual util::Status NBestEncode(
absl::string_view input, int nbest_size,
std::vector<std::vector<std::string>> *pieces) const;
// Same as Encode, but returns nbest results.
virtual util::Status NBestEncode(absl::string_view input, int nbest_size,
std::vector<std::vector<int>> *ids) const;
//////////////////////////////////////////////////////////////
// Sampling API.
// Unigram and BPE support sampling mode.
// - Unigram (--model_type=unigram):
// When `nbest_size` is positive value, approximately samples one
// segmentation from nbest candidates. When `nbest_size` is negative value,
// samples one segmentation from the hypotheses (Lattice) according to the
// generation probabilities using forward-filtering and backward-sampling
// algorithm. `alpha` is a smoothing parameter. The best segmentation
// (Viterbi segmentation) is more likely sampled when setting larger
// alpha. When alpha is 0.0, one segmentation is uniformly sampled from the
// nbest or lattice.
// `nbest_size` and `alpha` correspond to parameters `l` and `alpha`
// in https://arxiv.org/abs/1804.10959 (nbest_size < 0 means l = infinity)
//
// - BPE (--model_type=bpe):
// `alpha` is the merge probability `p` in https://arxiv.org/abs/1910.13267
// when alpha<=0, no sampling is performed but the best segmentation is
// returned. Nbest-based sampling is not supported so you need to specify
// nbest_size = 0 in BPE.
virtual util::Status SampleEncode(absl::string_view input, int nbest_size,
float alpha,
std::vector<std::string> *pieces) const;
// Same as above, but returns a sequence of ids.
virtual util::Status SampleEncode(absl::string_view input, int nbest_size,
float alpha, std::vector<int> *ids) const;
//////////////////////////////////////////////////////////////
// Advanced API returning SentencePieceText, which manages
// utf8-byte alignments between user-input/detokenized text
// and internal sentencepiece sequence.
//
// Given a UTF8 input, encodes it into SentencePieceText.
virtual util::Status Encode(absl::string_view input,
SentencePieceText *spt) const;
// Same as above, but returns NBestSentencePieceText.
virtual util::Status NBestEncode(absl::string_view input, int nbest_size,
NBestSentencePieceText *nbest_spt) const;
// Same as above, but samples one segmentation from the hypotheses
// (Lattice).
virtual util::Status SampleEncode(absl::string_view input, int nbest_size,
float alpha, SentencePieceText *spt) const;
// Given a sequence of pieces, decodes it into SentencePieceText.
virtual util::Status Decode(const std::vector<std::string> &pieces,
SentencePieceText *spt) const;
// Given a sequence of ids, decodes it into SentencePieceText.
virtual util::Status Decode(const std::vector<int> &ids,
SentencePieceText *spt) const;
//////////////////////////////////////////////////////////////
// Handy methods that return the result directly.
// These functions ignore internal errors.
#ifdef SWIG
#define DEFINE_SPP_DIRECT_FUNC_IMPL(FuncName, OutType, ...) \
OutType output; \
const auto _status = FuncName(__VA_ARGS__, &output); \
if (!_status.ok()) throw _status; \
return output;
#else
#define DEFINE_SPP_DIRECT_FUNC_IMPL(FuncName, OutType, ...) \
OutType output; \
FuncName(__VA_ARGS__, &output).IgnoreError(); \
return output;
#endif
virtual std::vector<std::string> EncodeAsPieces(
absl::string_view input) const {
DEFINE_SPP_DIRECT_FUNC_IMPL(Encode, std::vector<std::string>, input);
}
virtual std::vector<int> EncodeAsIds(absl::string_view input) const {
DEFINE_SPP_DIRECT_FUNC_IMPL(Encode, std::vector<int>, input);
}
virtual std::vector<std::vector<std::string>> NBestEncodeAsPieces(
absl::string_view input, int nbest_size) const {
DEFINE_SPP_DIRECT_FUNC_IMPL(
NBestEncode, std::vector<std::vector<std::string>>, input, nbest_size);
}
virtual std::vector<std::vector<int>> NBestEncodeAsIds(
absl::string_view input, int nbest_size) const {
DEFINE_SPP_DIRECT_FUNC_IMPL(NBestEncode, std::vector<std::vector<int>>,
input, nbest_size);
}
virtual std::vector<std::string> SampleEncodeAsPieces(absl::string_view input,
int nbest_size,
float alpha) const {
DEFINE_SPP_DIRECT_FUNC_IMPL(SampleEncode, std::vector<std::string>, input,
nbest_size, alpha);
}
virtual std::vector<int> SampleEncodeAsIds(absl::string_view input,
int nbest_size,
float alpha) const {
DEFINE_SPP_DIRECT_FUNC_IMPL(SampleEncode, std::vector<int>, input,
nbest_size, alpha);
}
virtual std::string DecodePieces(
const std::vector<std::string> &pieces) const {
DEFINE_SPP_DIRECT_FUNC_IMPL(Decode, std::string, pieces);
}
virtual std::string DecodeIds(const std::vector<int> &ids) const {
DEFINE_SPP_DIRECT_FUNC_IMPL(Decode, std::string, ids);
}
#undef DEFINE_SPP_DIRECT_FUNC_IMPL
// They are used in Python interface. Returns serialized proto.
// In python module, we can get access to the full Proto after
// deserialzing the returned byte sequence.
virtual util::bytes EncodeAsSerializedProto(absl::string_view input) const;
virtual util::bytes SampleEncodeAsSerializedProto(absl::string_view input,
int nbest_size,
float alpha) const;
virtual util::bytes NBestEncodeAsSerializedProto(absl::string_view input,
int nbest_size) const;
virtual util::bytes DecodePiecesAsSerializedProto(
const std::vector<std::string> &pieces) const;
virtual util::bytes DecodeIdsAsSerializedProto(
const std::vector<int> &ids) const;
//////////////////////////////////////////////////////////////
// Vocabulary management methods.
//
// Returns the size of sentence pieces, which is the same as
// the size of vocabulary for NMT.
virtual int GetPieceSize() const;
// Returns the vocab id of `piece`.
// Returns UNK(0) if `piece` is unknown.
virtual int PieceToId(absl::string_view piece) const;
// Returns the string representation of vocab with `id`.
virtual const std::string &IdToPiece(int id) const;
// Returns the score of `id`.
// Usually score is an emission log probability of unigram language model.
virtual float GetScore(int id) const;
// Returns true if `id` is unknown symbol.
virtual bool IsUnknown(int id) const;
// Returns true if `id` is control symbol.
virtual bool IsControl(int id) const;
// Returns true if `id` is unused symbol.
virtual bool IsUnused(int id) const;
// Returns true if `id` is byte symbol.
virtual bool IsByte(int id) const;
// Returns the reserved id.
// Returns -1 if not defined.
// Returns unknown (<unk>) id.
virtual int unk_id() const;
// Returns BOS (<s>) id.
virtual int bos_id() const;
// Returns EOS (</s>) id.
virtual int eos_id() const;
// Returns PAD (<pad>) id.
virtual int pad_id() const;
#ifndef SWIG
//////////////////////////////////////////////////////////////
// Model management.
//
// Allows injection of a mock model instance. `model` is moved.
void SetModel(std::unique_ptr<ModelInterface> &&model);
// Allows injection of a normalizer instance. `normalizer` is moved.
void SetNormalizer(std::unique_ptr<normalizer::Normalizer> &&normalizer);
#endif
// Returns immutable model proto. Useful to obtain extended
// or experimental parameters encoded in model_proto.
const ModelProto &model_proto() const;
// returns immutable model proto as std::string.
// Useful to save the state of this instance via Python's pickle object.
util::bytes serialized_model_proto() const;
private:
enum ExtraOption { REVERSE, BOS, EOS };
util::Status ParseExtraOptions(absl::string_view extra_option,
std::vector<ExtraOption> *extra_options) const;
util::Status ApplyExtraOptions(const std::vector<ExtraOption> &extra_options,
SentencePieceText *spt) const;
util::Status PopulateSentencePieceText(
absl::string_view input, absl::string_view normalized,
const std::vector<size_t> &norm_to_orig,
const std::vector<std::pair<absl::string_view, int>> &result,
SentencePieceText *spt) const;
std::unique_ptr<ModelInterface> model_;
std::unique_ptr<normalizer::Normalizer> normalizer_;
std::unique_ptr<normalizer::Normalizer> denormalizer_;
// Underlying model protocol buffer. The same lifetime as model_.
std::unique_ptr<ModelProto> model_proto_;
std::vector<ExtraOption> encode_extra_options_;
std::vector<ExtraOption> decode_extra_options_;
};
#ifndef SWIG
// IO related functions to absorb model formats.
namespace io {
// Loads `model_proto` from `filename`.
// We can instantiate SentencePieceProcessor as follows:
//
// auto model_proto = absl::make_unique<ModelProto>();
// io::LoadModelProto("//path/spm.model", model_proto.get());
// SentencePieceProcessor sp;
// CHECK_OK(sp.Load(std::move(model_proto)));
util::Status LoadModelProto(absl::string_view filename,
ModelProto *model_proto);
// Saves `model_proto` as `filename`.
util::Status SaveModelProto(absl::string_view filename,
const ModelProto &model_proto);
} // namespace io
#endif // SWIG
} // namespace sentencepiece
#endif // SENTENCEPIECE_PROCESSOR_H_
|