1 /**
2 *******************************************************************************
3 * Copyright (C) 2006-2012, International Business Machines Corporation
4 * and others. All Rights Reserved.
5 *******************************************************************************
6 */
7
8 #include "unicode/utypes.h"
9
10 #if !UCONFIG_NO_BREAK_ITERATION
11
12 #include "brkeng.h"
13 #include "dictbe.h"
14 #include "unicode/uniset.h"
15 #include "unicode/chariter.h"
16 #include "unicode/ubrk.h"
17 #include "uvector.h"
18 #include "uassert.h"
19 #include "unicode/normlzr.h"
20 #include "cmemory.h"
21 #include "dictionarydata.h"
22
23 U_NAMESPACE_BEGIN
24
25 /*
26 ******************************************************************
27 */
28
DictionaryBreakEngine(uint32_t breakTypes)29 DictionaryBreakEngine::DictionaryBreakEngine(uint32_t breakTypes) {
30 fTypes = breakTypes;
31 }
32
~DictionaryBreakEngine()33 DictionaryBreakEngine::~DictionaryBreakEngine() {
34 }
35
36 UBool
handles(UChar32 c,int32_t breakType) const37 DictionaryBreakEngine::handles(UChar32 c, int32_t breakType) const {
38 return (breakType >= 0 && breakType < 32 && (((uint32_t)1 << breakType) & fTypes)
39 && fSet.contains(c));
40 }
41
42 int32_t
findBreaks(UText * text,int32_t startPos,int32_t endPos,UBool reverse,int32_t breakType,UStack & foundBreaks) const43 DictionaryBreakEngine::findBreaks( UText *text,
44 int32_t startPos,
45 int32_t endPos,
46 UBool reverse,
47 int32_t breakType,
48 UStack &foundBreaks ) const {
49 int32_t result = 0;
50
51 // Find the span of characters included in the set.
52 int32_t start = (int32_t)utext_getNativeIndex(text);
53 int32_t current;
54 int32_t rangeStart;
55 int32_t rangeEnd;
56 UChar32 c = utext_current32(text);
57 if (reverse) {
58 UBool isDict = fSet.contains(c);
59 while((current = (int32_t)utext_getNativeIndex(text)) > startPos && isDict) {
60 c = utext_previous32(text);
61 isDict = fSet.contains(c);
62 }
63 rangeStart = (current < startPos) ? startPos : current+(isDict ? 0 : 1);
64 rangeEnd = start + 1;
65 }
66 else {
67 while((current = (int32_t)utext_getNativeIndex(text)) < endPos && fSet.contains(c)) {
68 utext_next32(text); // TODO: recast loop for postincrement
69 c = utext_current32(text);
70 }
71 rangeStart = start;
72 rangeEnd = current;
73 }
74 if (breakType >= 0 && breakType < 32 && (((uint32_t)1 << breakType) & fTypes)) {
75 result = divideUpDictionaryRange(text, rangeStart, rangeEnd, foundBreaks);
76 utext_setNativeIndex(text, current);
77 }
78
79 return result;
80 }
81
82 void
setCharacters(const UnicodeSet & set)83 DictionaryBreakEngine::setCharacters( const UnicodeSet &set ) {
84 fSet = set;
85 // Compact for caching
86 fSet.compact();
87 }
88
89 /*
90 ******************************************************************
91 */
92
93
94 // Helper class for improving readability of the Thai word break
95 // algorithm. The implementation is completely inline.
96
97 // List size, limited by the maximum number of words in the dictionary
98 // that form a nested sequence.
99 #define POSSIBLE_WORD_LIST_MAX 20
100
101 class PossibleWord {
102 private:
103 // list of word candidate lengths, in increasing length order
104 int32_t lengths[POSSIBLE_WORD_LIST_MAX];
105 int32_t count; // Count of candidates
106 int32_t prefix; // The longest match with a dictionary word
107 int32_t offset; // Offset in the text of these candidates
108 int mark; // The preferred candidate's offset
109 int current; // The candidate we're currently looking at
110
111 public:
112 PossibleWord();
113 ~PossibleWord();
114
115 // Fill the list of candidates if needed, select the longest, and return the number found
116 int candidates( UText *text, DictionaryMatcher *dict, int32_t rangeEnd );
117
118 // Select the currently marked candidate, point after it in the text, and invalidate self
119 int32_t acceptMarked( UText *text );
120
121 // Back up from the current candidate to the next shorter one; return TRUE if that exists
122 // and point the text after it
123 UBool backUp( UText *text );
124
125 // Return the longest prefix this candidate location shares with a dictionary word
126 int32_t longestPrefix();
127
128 // Mark the current candidate as the one we like
129 void markCurrent();
130 };
131
132 inline
PossibleWord()133 PossibleWord::PossibleWord() {
134 offset = -1;
135 }
136
137 inline
~PossibleWord()138 PossibleWord::~PossibleWord() {
139 }
140
141 inline int
candidates(UText * text,DictionaryMatcher * dict,int32_t rangeEnd)142 PossibleWord::candidates( UText *text, DictionaryMatcher *dict, int32_t rangeEnd ) {
143 // TODO: If getIndex is too slow, use offset < 0 and add discardAll()
144 int32_t start = (int32_t)utext_getNativeIndex(text);
145 if (start != offset) {
146 offset = start;
147 prefix = dict->matches(text, rangeEnd-start, lengths, count, sizeof(lengths)/sizeof(lengths[0]));
148 // Dictionary leaves text after longest prefix, not longest word. Back up.
149 if (count <= 0) {
150 utext_setNativeIndex(text, start);
151 }
152 }
153 if (count > 0) {
154 utext_setNativeIndex(text, start+lengths[count-1]);
155 }
156 current = count-1;
157 mark = current;
158 return count;
159 }
160
161 inline int32_t
acceptMarked(UText * text)162 PossibleWord::acceptMarked( UText *text ) {
163 utext_setNativeIndex(text, offset + lengths[mark]);
164 return lengths[mark];
165 }
166
167 inline UBool
backUp(UText * text)168 PossibleWord::backUp( UText *text ) {
169 if (current > 0) {
170 utext_setNativeIndex(text, offset + lengths[--current]);
171 return TRUE;
172 }
173 return FALSE;
174 }
175
176 inline int32_t
longestPrefix()177 PossibleWord::longestPrefix() {
178 return prefix;
179 }
180
181 inline void
markCurrent()182 PossibleWord::markCurrent() {
183 mark = current;
184 }
185
186 // How many words in a row are "good enough"?
187 #define THAI_LOOKAHEAD 3
188
189 // Will not combine a non-word with a preceding dictionary word longer than this
190 #define THAI_ROOT_COMBINE_THRESHOLD 3
191
192 // Will not combine a non-word that shares at least this much prefix with a
193 // dictionary word, with a preceding word
194 #define THAI_PREFIX_COMBINE_THRESHOLD 3
195
196 // Ellision character
197 #define THAI_PAIYANNOI 0x0E2F
198
199 // Repeat character
200 #define THAI_MAIYAMOK 0x0E46
201
202 // Minimum word size
203 #define THAI_MIN_WORD 2
204
205 // Minimum number of characters for two words
206 #define THAI_MIN_WORD_SPAN (THAI_MIN_WORD * 2)
207
ThaiBreakEngine(DictionaryMatcher * adoptDictionary,UErrorCode & status)208 ThaiBreakEngine::ThaiBreakEngine(DictionaryMatcher *adoptDictionary, UErrorCode &status)
209 : DictionaryBreakEngine((1<<UBRK_WORD) | (1<<UBRK_LINE)),
210 fDictionary(adoptDictionary)
211 {
212 fThaiWordSet.applyPattern(UNICODE_STRING_SIMPLE("[[:Thai:]&[:LineBreak=SA:]]"), status);
213 if (U_SUCCESS(status)) {
214 setCharacters(fThaiWordSet);
215 }
216 fMarkSet.applyPattern(UNICODE_STRING_SIMPLE("[[:Thai:]&[:LineBreak=SA:]&[:M:]]"), status);
217 fMarkSet.add(0x0020);
218 fEndWordSet = fThaiWordSet;
219 fEndWordSet.remove(0x0E31); // MAI HAN-AKAT
220 fEndWordSet.remove(0x0E40, 0x0E44); // SARA E through SARA AI MAIMALAI
221 fBeginWordSet.add(0x0E01, 0x0E2E); // KO KAI through HO NOKHUK
222 fBeginWordSet.add(0x0E40, 0x0E44); // SARA E through SARA AI MAIMALAI
223 fSuffixSet.add(THAI_PAIYANNOI);
224 fSuffixSet.add(THAI_MAIYAMOK);
225
226 // Compact for caching.
227 fMarkSet.compact();
228 fEndWordSet.compact();
229 fBeginWordSet.compact();
230 fSuffixSet.compact();
231 }
232
~ThaiBreakEngine()233 ThaiBreakEngine::~ThaiBreakEngine() {
234 delete fDictionary;
235 }
236
237 int32_t
divideUpDictionaryRange(UText * text,int32_t rangeStart,int32_t rangeEnd,UStack & foundBreaks) const238 ThaiBreakEngine::divideUpDictionaryRange( UText *text,
239 int32_t rangeStart,
240 int32_t rangeEnd,
241 UStack &foundBreaks ) const {
242 if ((rangeEnd - rangeStart) < THAI_MIN_WORD_SPAN) {
243 return 0; // Not enough characters for two words
244 }
245
246 uint32_t wordsFound = 0;
247 int32_t wordLength;
248 int32_t current;
249 UErrorCode status = U_ZERO_ERROR;
250 PossibleWord words[THAI_LOOKAHEAD];
251 UChar32 uc;
252
253 utext_setNativeIndex(text, rangeStart);
254
255 while (U_SUCCESS(status) && (current = (int32_t)utext_getNativeIndex(text)) < rangeEnd) {
256 wordLength = 0;
257
258 // Look for candidate words at the current position
259 int candidates = words[wordsFound%THAI_LOOKAHEAD].candidates(text, fDictionary, rangeEnd);
260
261 // If we found exactly one, use that
262 if (candidates == 1) {
263 wordLength = words[wordsFound % THAI_LOOKAHEAD].acceptMarked(text);
264 wordsFound += 1;
265 }
266 // If there was more than one, see which one can take us forward the most words
267 else if (candidates > 1) {
268 // If we're already at the end of the range, we're done
269 if ((int32_t)utext_getNativeIndex(text) >= rangeEnd) {
270 goto foundBest;
271 }
272 do {
273 int wordsMatched = 1;
274 if (words[(wordsFound + 1) % THAI_LOOKAHEAD].candidates(text, fDictionary, rangeEnd) > 0) {
275 if (wordsMatched < 2) {
276 // Followed by another dictionary word; mark first word as a good candidate
277 words[wordsFound%THAI_LOOKAHEAD].markCurrent();
278 wordsMatched = 2;
279 }
280
281 // If we're already at the end of the range, we're done
282 if ((int32_t)utext_getNativeIndex(text) >= rangeEnd) {
283 goto foundBest;
284 }
285
286 // See if any of the possible second words is followed by a third word
287 do {
288 // If we find a third word, stop right away
289 if (words[(wordsFound + 2) % THAI_LOOKAHEAD].candidates(text, fDictionary, rangeEnd)) {
290 words[wordsFound % THAI_LOOKAHEAD].markCurrent();
291 goto foundBest;
292 }
293 }
294 while (words[(wordsFound + 1) % THAI_LOOKAHEAD].backUp(text));
295 }
296 }
297 while (words[wordsFound % THAI_LOOKAHEAD].backUp(text));
298 foundBest:
299 wordLength = words[wordsFound % THAI_LOOKAHEAD].acceptMarked(text);
300 wordsFound += 1;
301 }
302
303 // We come here after having either found a word or not. We look ahead to the
304 // next word. If it's not a dictionary word, we will combine it withe the word we
305 // just found (if there is one), but only if the preceding word does not exceed
306 // the threshold.
307 // The text iterator should now be positioned at the end of the word we found.
308 if ((int32_t)utext_getNativeIndex(text) < rangeEnd && wordLength < THAI_ROOT_COMBINE_THRESHOLD) {
309 // if it is a dictionary word, do nothing. If it isn't, then if there is
310 // no preceding word, or the non-word shares less than the minimum threshold
311 // of characters with a dictionary word, then scan to resynchronize
312 if (words[wordsFound % THAI_LOOKAHEAD].candidates(text, fDictionary, rangeEnd) <= 0
313 && (wordLength == 0
314 || words[wordsFound%THAI_LOOKAHEAD].longestPrefix() < THAI_PREFIX_COMBINE_THRESHOLD)) {
315 // Look for a plausible word boundary
316 //TODO: This section will need a rework for UText.
317 int32_t remaining = rangeEnd - (current+wordLength);
318 UChar32 pc = utext_current32(text);
319 int32_t chars = 0;
320 for (;;) {
321 utext_next32(text);
322 uc = utext_current32(text);
323 // TODO: Here we're counting on the fact that the SA languages are all
324 // in the BMP. This should get fixed with the UText rework.
325 chars += 1;
326 if (--remaining <= 0) {
327 break;
328 }
329 if (fEndWordSet.contains(pc) && fBeginWordSet.contains(uc)) {
330 // Maybe. See if it's in the dictionary.
331 // NOTE: In the original Apple code, checked that the next
332 // two characters after uc were not 0x0E4C THANTHAKHAT before
333 // checking the dictionary. That is just a performance filter,
334 // but it's not clear it's faster than checking the trie.
335 int candidates = words[(wordsFound + 1) % THAI_LOOKAHEAD].candidates(text, fDictionary, rangeEnd);
336 utext_setNativeIndex(text, current + wordLength + chars);
337 if (candidates > 0) {
338 break;
339 }
340 }
341 pc = uc;
342 }
343
344 // Bump the word count if there wasn't already one
345 if (wordLength <= 0) {
346 wordsFound += 1;
347 }
348
349 // Update the length with the passed-over characters
350 wordLength += chars;
351 }
352 else {
353 // Back up to where we were for next iteration
354 utext_setNativeIndex(text, current+wordLength);
355 }
356 }
357
358 // Never stop before a combining mark.
359 int32_t currPos;
360 while ((currPos = (int32_t)utext_getNativeIndex(text)) < rangeEnd && fMarkSet.contains(utext_current32(text))) {
361 utext_next32(text);
362 wordLength += (int32_t)utext_getNativeIndex(text) - currPos;
363 }
364
365 // Look ahead for possible suffixes if a dictionary word does not follow.
366 // We do this in code rather than using a rule so that the heuristic
367 // resynch continues to function. For example, one of the suffix characters
368 // could be a typo in the middle of a word.
369 if ((int32_t)utext_getNativeIndex(text) < rangeEnd && wordLength > 0) {
370 if (words[wordsFound%THAI_LOOKAHEAD].candidates(text, fDictionary, rangeEnd) <= 0
371 && fSuffixSet.contains(uc = utext_current32(text))) {
372 if (uc == THAI_PAIYANNOI) {
373 if (!fSuffixSet.contains(utext_previous32(text))) {
374 // Skip over previous end and PAIYANNOI
375 utext_next32(text);
376 utext_next32(text);
377 wordLength += 1; // Add PAIYANNOI to word
378 uc = utext_current32(text); // Fetch next character
379 }
380 else {
381 // Restore prior position
382 utext_next32(text);
383 }
384 }
385 if (uc == THAI_MAIYAMOK) {
386 if (utext_previous32(text) != THAI_MAIYAMOK) {
387 // Skip over previous end and MAIYAMOK
388 utext_next32(text);
389 utext_next32(text);
390 wordLength += 1; // Add MAIYAMOK to word
391 }
392 else {
393 // Restore prior position
394 utext_next32(text);
395 }
396 }
397 }
398 else {
399 utext_setNativeIndex(text, current+wordLength);
400 }
401 }
402
403 // Did we find a word on this iteration? If so, push it on the break stack
404 if (wordLength > 0) {
405 foundBreaks.push((current+wordLength), status);
406 }
407 }
408
409 // Don't return a break for the end of the dictionary range if there is one there.
410 if (foundBreaks.peeki() >= rangeEnd) {
411 (void) foundBreaks.popi();
412 wordsFound -= 1;
413 }
414
415 return wordsFound;
416 }
417
418 // How many words in a row are "good enough"?
419 #define KHMER_LOOKAHEAD 3
420
421 // Will not combine a non-word with a preceding dictionary word longer than this
422 #define KHMER_ROOT_COMBINE_THRESHOLD 3
423
424 // Will not combine a non-word that shares at least this much prefix with a
425 // dictionary word, with a preceding word
426 #define KHMER_PREFIX_COMBINE_THRESHOLD 3
427
428 // Minimum word size
429 #define KHMER_MIN_WORD 2
430
431 // Minimum number of characters for two words
432 #define KHMER_MIN_WORD_SPAN (KHMER_MIN_WORD * 2)
433
KhmerBreakEngine(DictionaryMatcher * adoptDictionary,UErrorCode & status)434 KhmerBreakEngine::KhmerBreakEngine(DictionaryMatcher *adoptDictionary, UErrorCode &status)
435 : DictionaryBreakEngine((1 << UBRK_WORD) | (1 << UBRK_LINE)),
436 fDictionary(adoptDictionary)
437 {
438 fKhmerWordSet.applyPattern(UNICODE_STRING_SIMPLE("[[:Khmr:]&[:LineBreak=SA:]]"), status);
439 if (U_SUCCESS(status)) {
440 setCharacters(fKhmerWordSet);
441 }
442 fMarkSet.applyPattern(UNICODE_STRING_SIMPLE("[[:Khmr:]&[:LineBreak=SA:]&[:M:]]"), status);
443 fMarkSet.add(0x0020);
444 fEndWordSet = fKhmerWordSet;
445 fBeginWordSet.add(0x1780, 0x17B3);
446 //fBeginWordSet.add(0x17A3, 0x17A4); // deprecated vowels
447 //fEndWordSet.remove(0x17A5, 0x17A9); // Khmer independent vowels that can't end a word
448 //fEndWordSet.remove(0x17B2); // Khmer independent vowel that can't end a word
449 fEndWordSet.remove(0x17D2); // KHMER SIGN COENG that combines some following characters
450 //fEndWordSet.remove(0x17B6, 0x17C5); // Remove dependent vowels
451 // fEndWordSet.remove(0x0E31); // MAI HAN-AKAT
452 // fEndWordSet.remove(0x0E40, 0x0E44); // SARA E through SARA AI MAIMALAI
453 // fBeginWordSet.add(0x0E01, 0x0E2E); // KO KAI through HO NOKHUK
454 // fBeginWordSet.add(0x0E40, 0x0E44); // SARA E through SARA AI MAIMALAI
455 // fSuffixSet.add(THAI_PAIYANNOI);
456 // fSuffixSet.add(THAI_MAIYAMOK);
457
458 // Compact for caching.
459 fMarkSet.compact();
460 fEndWordSet.compact();
461 fBeginWordSet.compact();
462 // fSuffixSet.compact();
463 }
464
~KhmerBreakEngine()465 KhmerBreakEngine::~KhmerBreakEngine() {
466 delete fDictionary;
467 }
468
469 int32_t
divideUpDictionaryRange(UText * text,int32_t rangeStart,int32_t rangeEnd,UStack & foundBreaks) const470 KhmerBreakEngine::divideUpDictionaryRange( UText *text,
471 int32_t rangeStart,
472 int32_t rangeEnd,
473 UStack &foundBreaks ) const {
474 if ((rangeEnd - rangeStart) < KHMER_MIN_WORD_SPAN) {
475 return 0; // Not enough characters for two words
476 }
477
478 uint32_t wordsFound = 0;
479 int32_t wordLength;
480 int32_t current;
481 UErrorCode status = U_ZERO_ERROR;
482 PossibleWord words[KHMER_LOOKAHEAD];
483 UChar32 uc;
484
485 utext_setNativeIndex(text, rangeStart);
486
487 while (U_SUCCESS(status) && (current = (int32_t)utext_getNativeIndex(text)) < rangeEnd) {
488 wordLength = 0;
489
490 // Look for candidate words at the current position
491 int candidates = words[wordsFound%KHMER_LOOKAHEAD].candidates(text, fDictionary, rangeEnd);
492
493 // If we found exactly one, use that
494 if (candidates == 1) {
495 wordLength = words[wordsFound%KHMER_LOOKAHEAD].acceptMarked(text);
496 wordsFound += 1;
497 }
498
499 // If there was more than one, see which one can take us forward the most words
500 else if (candidates > 1) {
501 // If we're already at the end of the range, we're done
502 if ((int32_t)utext_getNativeIndex(text) >= rangeEnd) {
503 goto foundBest;
504 }
505 do {
506 int wordsMatched = 1;
507 if (words[(wordsFound + 1) % KHMER_LOOKAHEAD].candidates(text, fDictionary, rangeEnd) > 0) {
508 if (wordsMatched < 2) {
509 // Followed by another dictionary word; mark first word as a good candidate
510 words[wordsFound % KHMER_LOOKAHEAD].markCurrent();
511 wordsMatched = 2;
512 }
513
514 // If we're already at the end of the range, we're done
515 if ((int32_t)utext_getNativeIndex(text) >= rangeEnd) {
516 goto foundBest;
517 }
518
519 // See if any of the possible second words is followed by a third word
520 do {
521 // If we find a third word, stop right away
522 if (words[(wordsFound + 2) % KHMER_LOOKAHEAD].candidates(text, fDictionary, rangeEnd)) {
523 words[wordsFound % KHMER_LOOKAHEAD].markCurrent();
524 goto foundBest;
525 }
526 }
527 while (words[(wordsFound + 1) % KHMER_LOOKAHEAD].backUp(text));
528 }
529 }
530 while (words[wordsFound % KHMER_LOOKAHEAD].backUp(text));
531 foundBest:
532 wordLength = words[wordsFound % KHMER_LOOKAHEAD].acceptMarked(text);
533 wordsFound += 1;
534 }
535
536 // We come here after having either found a word or not. We look ahead to the
537 // next word. If it's not a dictionary word, we will combine it with the word we
538 // just found (if there is one), but only if the preceding word does not exceed
539 // the threshold.
540 // The text iterator should now be positioned at the end of the word we found.
541 if ((int32_t)utext_getNativeIndex(text) < rangeEnd && wordLength < KHMER_ROOT_COMBINE_THRESHOLD) {
542 // if it is a dictionary word, do nothing. If it isn't, then if there is
543 // no preceding word, or the non-word shares less than the minimum threshold
544 // of characters with a dictionary word, then scan to resynchronize
545 if (words[wordsFound % KHMER_LOOKAHEAD].candidates(text, fDictionary, rangeEnd) <= 0
546 && (wordLength == 0
547 || words[wordsFound % KHMER_LOOKAHEAD].longestPrefix() < KHMER_PREFIX_COMBINE_THRESHOLD)) {
548 // Look for a plausible word boundary
549 //TODO: This section will need a rework for UText.
550 int32_t remaining = rangeEnd - (current+wordLength);
551 UChar32 pc = utext_current32(text);
552 int32_t chars = 0;
553 for (;;) {
554 utext_next32(text);
555 uc = utext_current32(text);
556 // TODO: Here we're counting on the fact that the SA languages are all
557 // in the BMP. This should get fixed with the UText rework.
558 chars += 1;
559 if (--remaining <= 0) {
560 break;
561 }
562 if (fEndWordSet.contains(pc) && fBeginWordSet.contains(uc)) {
563 // Maybe. See if it's in the dictionary.
564 int candidates = words[(wordsFound + 1) % KHMER_LOOKAHEAD].candidates(text, fDictionary, rangeEnd);
565 utext_setNativeIndex(text, current+wordLength+chars);
566 if (candidates > 0) {
567 break;
568 }
569 }
570 pc = uc;
571 }
572
573 // Bump the word count if there wasn't already one
574 if (wordLength <= 0) {
575 wordsFound += 1;
576 }
577
578 // Update the length with the passed-over characters
579 wordLength += chars;
580 }
581 else {
582 // Back up to where we were for next iteration
583 utext_setNativeIndex(text, current+wordLength);
584 }
585 }
586
587 // Never stop before a combining mark.
588 int32_t currPos;
589 while ((currPos = (int32_t)utext_getNativeIndex(text)) < rangeEnd && fMarkSet.contains(utext_current32(text))) {
590 utext_next32(text);
591 wordLength += (int32_t)utext_getNativeIndex(text) - currPos;
592 }
593
594 // Look ahead for possible suffixes if a dictionary word does not follow.
595 // We do this in code rather than using a rule so that the heuristic
596 // resynch continues to function. For example, one of the suffix characters
597 // could be a typo in the middle of a word.
598 // if ((int32_t)utext_getNativeIndex(text) < rangeEnd && wordLength > 0) {
599 // if (words[wordsFound%KHMER_LOOKAHEAD].candidates(text, fDictionary, rangeEnd) <= 0
600 // && fSuffixSet.contains(uc = utext_current32(text))) {
601 // if (uc == KHMER_PAIYANNOI) {
602 // if (!fSuffixSet.contains(utext_previous32(text))) {
603 // // Skip over previous end and PAIYANNOI
604 // utext_next32(text);
605 // utext_next32(text);
606 // wordLength += 1; // Add PAIYANNOI to word
607 // uc = utext_current32(text); // Fetch next character
608 // }
609 // else {
610 // // Restore prior position
611 // utext_next32(text);
612 // }
613 // }
614 // if (uc == KHMER_MAIYAMOK) {
615 // if (utext_previous32(text) != KHMER_MAIYAMOK) {
616 // // Skip over previous end and MAIYAMOK
617 // utext_next32(text);
618 // utext_next32(text);
619 // wordLength += 1; // Add MAIYAMOK to word
620 // }
621 // else {
622 // // Restore prior position
623 // utext_next32(text);
624 // }
625 // }
626 // }
627 // else {
628 // utext_setNativeIndex(text, current+wordLength);
629 // }
630 // }
631
632 // Did we find a word on this iteration? If so, push it on the break stack
633 if (wordLength > 0) {
634 foundBreaks.push((current+wordLength), status);
635 }
636 }
637
638 // Don't return a break for the end of the dictionary range if there is one there.
639 if (foundBreaks.peeki() >= rangeEnd) {
640 (void) foundBreaks.popi();
641 wordsFound -= 1;
642 }
643
644 return wordsFound;
645 }
646
647 #if !UCONFIG_NO_NORMALIZATION
648 /*
649 ******************************************************************
650 * CjkBreakEngine
651 */
652 static const uint32_t kuint32max = 0xFFFFFFFF;
CjkBreakEngine(DictionaryMatcher * adoptDictionary,LanguageType type,UErrorCode & status)653 CjkBreakEngine::CjkBreakEngine(DictionaryMatcher *adoptDictionary, LanguageType type, UErrorCode &status)
654 : DictionaryBreakEngine(1 << UBRK_WORD), fDictionary(adoptDictionary) {
655 // Korean dictionary only includes Hangul syllables
656 fHangulWordSet.applyPattern(UNICODE_STRING_SIMPLE("[\\uac00-\\ud7a3]"), status);
657 fHanWordSet.applyPattern(UNICODE_STRING_SIMPLE("[:Han:]"), status);
658 fKatakanaWordSet.applyPattern(UNICODE_STRING_SIMPLE("[[:Katakana:]\\uff9e\\uff9f]"), status);
659 fHiraganaWordSet.applyPattern(UNICODE_STRING_SIMPLE("[:Hiragana:]"), status);
660
661 if (U_SUCCESS(status)) {
662 // handle Korean and Japanese/Chinese using different dictionaries
663 if (type == kKorean) {
664 setCharacters(fHangulWordSet);
665 } else { //Chinese and Japanese
666 UnicodeSet cjSet;
667 cjSet.addAll(fHanWordSet);
668 cjSet.addAll(fKatakanaWordSet);
669 cjSet.addAll(fHiraganaWordSet);
670 cjSet.add(UNICODE_STRING_SIMPLE("\\uff70\\u30fc"));
671 setCharacters(cjSet);
672 }
673 }
674 }
675
~CjkBreakEngine()676 CjkBreakEngine::~CjkBreakEngine(){
677 delete fDictionary;
678 }
679
680 // The katakanaCost values below are based on the length frequencies of all
681 // katakana phrases in the dictionary
682 static const int kMaxKatakanaLength = 8;
683 static const int kMaxKatakanaGroupLength = 20;
684 static const uint32_t maxSnlp = 255;
685
getKatakanaCost(int wordLength)686 static inline uint32_t getKatakanaCost(int wordLength){
687 //TODO: fill array with actual values from dictionary!
688 static const uint32_t katakanaCost[kMaxKatakanaLength + 1]
689 = {8192, 984, 408, 240, 204, 252, 300, 372, 480};
690 return (wordLength > kMaxKatakanaLength) ? 8192 : katakanaCost[wordLength];
691 }
692
isKatakana(uint16_t value)693 static inline bool isKatakana(uint16_t value) {
694 return (value >= 0x30A1u && value <= 0x30FEu && value != 0x30FBu) ||
695 (value >= 0xFF66u && value <= 0xFF9fu);
696 }
697
698 // A very simple helper class to streamline the buffer handling in
699 // divideUpDictionaryRange.
700 template<class T, size_t N>
701 class AutoBuffer {
702 public:
AutoBuffer(size_t size)703 AutoBuffer(size_t size) : buffer(stackBuffer), capacity(N) {
704 if (size > N) {
705 buffer = reinterpret_cast<T*>(uprv_malloc(sizeof(T)*size));
706 capacity = size;
707 }
708 }
~AutoBuffer()709 ~AutoBuffer() {
710 if (buffer != stackBuffer)
711 uprv_free(buffer);
712 }
713
elems()714 T* elems() {
715 return buffer;
716 }
717
operator [](size_t i) const718 const T& operator[] (size_t i) const {
719 return buffer[i];
720 }
721
operator [](size_t i)722 T& operator[] (size_t i) {
723 return buffer[i];
724 }
725
726 // resize without copy
resize(size_t size)727 void resize(size_t size) {
728 if (size <= capacity)
729 return;
730 if (buffer != stackBuffer)
731 uprv_free(buffer);
732 buffer = reinterpret_cast<T*>(uprv_malloc(sizeof(T)*size));
733 capacity = size;
734 }
735
736 private:
737 T stackBuffer[N];
738 T* buffer;
739 AutoBuffer();
740 size_t capacity;
741 };
742
743
744 /*
745 * @param text A UText representing the text
746 * @param rangeStart The start of the range of dictionary characters
747 * @param rangeEnd The end of the range of dictionary characters
748 * @param foundBreaks Output of C array of int32_t break positions, or 0
749 * @return The number of breaks found
750 */
751 int32_t
divideUpDictionaryRange(UText * text,int32_t rangeStart,int32_t rangeEnd,UStack & foundBreaks) const752 CjkBreakEngine::divideUpDictionaryRange( UText *text,
753 int32_t rangeStart,
754 int32_t rangeEnd,
755 UStack &foundBreaks ) const {
756 if (rangeStart >= rangeEnd) {
757 return 0;
758 }
759
760 const size_t defaultInputLength = 80;
761 size_t inputLength = rangeEnd - rangeStart;
762 // TODO: Replace by UnicodeString.
763 AutoBuffer<UChar, defaultInputLength> charString(inputLength);
764
765 // Normalize the input string and put it in normalizedText.
766 // The map from the indices of the normalized input to the raw
767 // input is kept in charPositions.
768 UErrorCode status = U_ZERO_ERROR;
769 utext_extract(text, rangeStart, rangeEnd, charString.elems(), inputLength, &status);
770 if (U_FAILURE(status)) {
771 return 0;
772 }
773
774 UnicodeString inputString(charString.elems(), inputLength);
775 // TODO: Use Normalizer2.
776 UNormalizationMode norm_mode = UNORM_NFKC;
777 UBool isNormalized =
778 Normalizer::quickCheck(inputString, norm_mode, status) == UNORM_YES ||
779 Normalizer::isNormalized(inputString, norm_mode, status);
780
781 // TODO: Replace by UVector32.
782 AutoBuffer<int32_t, defaultInputLength> charPositions(inputLength + 1);
783 int numChars = 0;
784 UText normalizedText = UTEXT_INITIALIZER;
785 // Needs to be declared here because normalizedText holds onto its buffer.
786 UnicodeString normalizedString;
787 if (isNormalized) {
788 int32_t index = 0;
789 charPositions[0] = 0;
790 while(index < inputString.length()) {
791 index = inputString.moveIndex32(index, 1);
792 charPositions[++numChars] = index;
793 }
794 utext_openUnicodeString(&normalizedText, &inputString, &status);
795 }
796 else {
797 Normalizer::normalize(inputString, norm_mode, 0, normalizedString, status);
798 if (U_FAILURE(status)) {
799 return 0;
800 }
801 charPositions.resize(normalizedString.length() + 1);
802 Normalizer normalizer(charString.elems(), inputLength, norm_mode);
803 int32_t index = 0;
804 charPositions[0] = 0;
805 while(index < normalizer.endIndex()){
806 /* UChar32 uc = */ normalizer.next();
807 charPositions[++numChars] = index = normalizer.getIndex();
808 }
809 utext_openUnicodeString(&normalizedText, &normalizedString, &status);
810 }
811
812 if (U_FAILURE(status)) {
813 return 0;
814 }
815
816 // From this point on, all the indices refer to the indices of
817 // the normalized input string.
818
819 // bestSnlp[i] is the snlp of the best segmentation of the first i
820 // characters in the range to be matched.
821 // TODO: Replace by UVector32.
822 AutoBuffer<uint32_t, defaultInputLength> bestSnlp(numChars + 1);
823 bestSnlp[0] = 0;
824 for(int i = 1; i <= numChars; i++) {
825 bestSnlp[i] = kuint32max;
826 }
827
828 // prev[i] is the index of the last CJK character in the previous word in
829 // the best segmentation of the first i characters.
830 // TODO: Replace by UVector32.
831 AutoBuffer<int, defaultInputLength> prev(numChars + 1);
832 for(int i = 0; i <= numChars; i++){
833 prev[i] = -1;
834 }
835
836 const size_t maxWordSize = 20;
837 // TODO: Replace both with UVector32.
838 AutoBuffer<int32_t, maxWordSize> values(numChars);
839 AutoBuffer<int32_t, maxWordSize> lengths(numChars);
840
841 // Dynamic programming to find the best segmentation.
842 bool is_prev_katakana = false;
843 for (int32_t i = 0; i < numChars; ++i) {
844 //utext_setNativeIndex(text, rangeStart + i);
845 utext_setNativeIndex(&normalizedText, i);
846 if (bestSnlp[i] == kuint32max)
847 continue;
848
849 int32_t count;
850 // limit maximum word length matched to size of current substring
851 int32_t maxSearchLength = (i + maxWordSize < (size_t) numChars)? maxWordSize : (numChars - i);
852
853 fDictionary->matches(&normalizedText, maxSearchLength, lengths.elems(), count, maxSearchLength, values.elems());
854
855 // if there are no single character matches found in the dictionary
856 // starting with this charcter, treat character as a 1-character word
857 // with the highest value possible, i.e. the least likely to occur.
858 // Exclude Korean characters from this treatment, as they should be left
859 // together by default.
860 if((count == 0 || lengths[0] != 1) &&
861 !fHangulWordSet.contains(utext_current32(&normalizedText))) {
862 values[count] = maxSnlp;
863 lengths[count++] = 1;
864 }
865
866 for (int j = 0; j < count; j++) {
867 uint32_t newSnlp = bestSnlp[i] + values[j];
868 if (newSnlp < bestSnlp[lengths[j] + i]) {
869 bestSnlp[lengths[j] + i] = newSnlp;
870 prev[lengths[j] + i] = i;
871 }
872 }
873
874 // In Japanese,
875 // Katakana word in single character is pretty rare. So we apply
876 // the following heuristic to Katakana: any continuous run of Katakana
877 // characters is considered a candidate word with a default cost
878 // specified in the katakanaCost table according to its length.
879 //utext_setNativeIndex(text, rangeStart + i);
880 utext_setNativeIndex(&normalizedText, i);
881 bool is_katakana = isKatakana(utext_current32(&normalizedText));
882 if (!is_prev_katakana && is_katakana) {
883 int j = i + 1;
884 utext_next32(&normalizedText);
885 // Find the end of the continuous run of Katakana characters
886 while (j < numChars && (j - i) < kMaxKatakanaGroupLength &&
887 isKatakana(utext_current32(&normalizedText))) {
888 utext_next32(&normalizedText);
889 ++j;
890 }
891 if ((j - i) < kMaxKatakanaGroupLength) {
892 uint32_t newSnlp = bestSnlp[i] + getKatakanaCost(j - i);
893 if (newSnlp < bestSnlp[j]) {
894 bestSnlp[j] = newSnlp;
895 prev[j] = i;
896 }
897 }
898 }
899 is_prev_katakana = is_katakana;
900 }
901
902 // Start pushing the optimal offset index into t_boundary (t for tentative).
903 // prev[numChars] is guaranteed to be meaningful.
904 // We'll first push in the reverse order, i.e.,
905 // t_boundary[0] = numChars, and afterwards do a swap.
906 // TODO: Replace by UVector32.
907 AutoBuffer<int, maxWordSize> t_boundary(numChars + 1);
908
909 int numBreaks = 0;
910 // No segmentation found, set boundary to end of range
911 if (bestSnlp[numChars] == kuint32max) {
912 t_boundary[numBreaks++] = numChars;
913 } else {
914 for (int i = numChars; i > 0; i = prev[i]) {
915 t_boundary[numBreaks++] = i;
916 }
917 U_ASSERT(prev[t_boundary[numBreaks - 1]] == 0);
918 }
919
920 // Reverse offset index in t_boundary.
921 // Don't add a break for the start of the dictionary range if there is one
922 // there already.
923 if (foundBreaks.size() == 0 || foundBreaks.peeki() < rangeStart) {
924 t_boundary[numBreaks++] = 0;
925 }
926
927 // Now that we're done, convert positions in t_bdry[] (indices in
928 // the normalized input string) back to indices in the raw input string
929 // while reversing t_bdry and pushing values to foundBreaks.
930 for (int i = numBreaks-1; i >= 0; i--) {
931 foundBreaks.push(charPositions[t_boundary[i]] + rangeStart, status);
932 }
933
934 utext_close(&normalizedText);
935 return numBreaks;
936 }
937 #endif
938
939 U_NAMESPACE_END
940
941 #endif /* #if !UCONFIG_NO_BREAK_ITERATION */
942
943