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comparison: intl/icu/source/common/caniter.cpp

intl/icu/source/common/caniter.cpp

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1 /*
2 *****************************************************************************
3 * Copyright (C) 1996-2011, International Business Machines Corporation and *
4 * others. All Rights Reserved. *
5 *****************************************************************************
6 */
7
8 #include "unicode/utypes.h"
9
10 #if !UCONFIG_NO_NORMALIZATION
11
12 #include "unicode/caniter.h"
13 #include "unicode/normalizer2.h"
14 #include "unicode/uchar.h"
15 #include "unicode/uniset.h"
16 #include "unicode/usetiter.h"
17 #include "unicode/ustring.h"
18 #include "unicode/utf16.h"
19 #include "cmemory.h"
20 #include "hash.h"
21 #include "normalizer2impl.h"
22
23 /**
24 * This class allows one to iterate through all the strings that are canonically equivalent to a given
25 * string. For example, here are some sample results:
26 Results for: {LATIN CAPITAL LETTER A WITH RING ABOVE}{LATIN SMALL LETTER D}{COMBINING DOT ABOVE}{COMBINING CEDILLA}
27 1: \u0041\u030A\u0064\u0307\u0327
28 = {LATIN CAPITAL LETTER A}{COMBINING RING ABOVE}{LATIN SMALL LETTER D}{COMBINING DOT ABOVE}{COMBINING CEDILLA}
29 2: \u0041\u030A\u0064\u0327\u0307
30 = {LATIN CAPITAL LETTER A}{COMBINING RING ABOVE}{LATIN SMALL LETTER D}{COMBINING CEDILLA}{COMBINING DOT ABOVE}
31 3: \u0041\u030A\u1E0B\u0327
32 = {LATIN CAPITAL LETTER A}{COMBINING RING ABOVE}{LATIN SMALL LETTER D WITH DOT ABOVE}{COMBINING CEDILLA}
33 4: \u0041\u030A\u1E11\u0307
34 = {LATIN CAPITAL LETTER A}{COMBINING RING ABOVE}{LATIN SMALL LETTER D WITH CEDILLA}{COMBINING DOT ABOVE}
35 5: \u00C5\u0064\u0307\u0327
36 = {LATIN CAPITAL LETTER A WITH RING ABOVE}{LATIN SMALL LETTER D}{COMBINING DOT ABOVE}{COMBINING CEDILLA}
37 6: \u00C5\u0064\u0327\u0307
38 = {LATIN CAPITAL LETTER A WITH RING ABOVE}{LATIN SMALL LETTER D}{COMBINING CEDILLA}{COMBINING DOT ABOVE}
39 7: \u00C5\u1E0B\u0327
40 = {LATIN CAPITAL LETTER A WITH RING ABOVE}{LATIN SMALL LETTER D WITH DOT ABOVE}{COMBINING CEDILLA}
41 8: \u00C5\u1E11\u0307
42 = {LATIN CAPITAL LETTER A WITH RING ABOVE}{LATIN SMALL LETTER D WITH CEDILLA}{COMBINING DOT ABOVE}
43 9: \u212B\u0064\u0307\u0327
44 = {ANGSTROM SIGN}{LATIN SMALL LETTER D}{COMBINING DOT ABOVE}{COMBINING CEDILLA}
45 10: \u212B\u0064\u0327\u0307
46 = {ANGSTROM SIGN}{LATIN SMALL LETTER D}{COMBINING CEDILLA}{COMBINING DOT ABOVE}
47 11: \u212B\u1E0B\u0327
48 = {ANGSTROM SIGN}{LATIN SMALL LETTER D WITH DOT ABOVE}{COMBINING CEDILLA}
49 12: \u212B\u1E11\u0307
50 = {ANGSTROM SIGN}{LATIN SMALL LETTER D WITH CEDILLA}{COMBINING DOT ABOVE}
51 *<br>Note: the code is intended for use with small strings, and is not suitable for larger ones,
52 * since it has not been optimized for that situation.
53 *@author M. Davis
54 *@draft
55 */
56
57 // public
58
59 U_NAMESPACE_BEGIN
60
61 // TODO: add boilerplate methods.
62
63 UOBJECT_DEFINE_RTTI_IMPLEMENTATION(CanonicalIterator)
64
65 /**
66 *@param source string to get results for
67 */
68 CanonicalIterator::CanonicalIterator(const UnicodeString &sourceStr, UErrorCode &status) :
69 pieces(NULL),
70 pieces_length(0),
71 pieces_lengths(NULL),
72 current(NULL),
73 current_length(0),
74 nfd(*Normalizer2Factory::getNFDInstance(status)),
75 nfcImpl(*Normalizer2Factory::getNFCImpl(status))
76 {
77 if(U_SUCCESS(status) && nfcImpl.ensureCanonIterData(status)) {
78 setSource(sourceStr, status);
79 }
80 }
81
82 CanonicalIterator::~CanonicalIterator() {
83 cleanPieces();
84 }
85
86 void CanonicalIterator::cleanPieces() {
87 int32_t i = 0;
88 if(pieces != NULL) {
89 for(i = 0; i < pieces_length; i++) {
90 if(pieces[i] != NULL) {
91 delete[] pieces[i];
92 }
93 }
94 uprv_free(pieces);
95 pieces = NULL;
96 pieces_length = 0;
97 }
98 if(pieces_lengths != NULL) {
99 uprv_free(pieces_lengths);
100 pieces_lengths = NULL;
101 }
102 if(current != NULL) {
103 uprv_free(current);
104 current = NULL;
105 current_length = 0;
106 }
107 }
108
109 /**
110 *@return gets the source: NOTE: it is the NFD form of source
111 */
112 UnicodeString CanonicalIterator::getSource() {
113 return source;
114 }
115
116 /**
117 * Resets the iterator so that one can start again from the beginning.
118 */
119 void CanonicalIterator::reset() {
120 done = FALSE;
121 for (int i = 0; i < current_length; ++i) {
122 current[i] = 0;
123 }
124 }
125
126 /**
127 *@return the next string that is canonically equivalent. The value null is returned when
128 * the iteration is done.
129 */
130 UnicodeString CanonicalIterator::next() {
131 int32_t i = 0;
132
133 if (done) {
134 buffer.setToBogus();
135 return buffer;
136 }
137
138 // delete old contents
139 buffer.remove();
140
141 // construct return value
142
143 for (i = 0; i < pieces_length; ++i) {
144 buffer.append(pieces[i][current[i]]);
145 }
146 //String result = buffer.toString(); // not needed
147
148 // find next value for next time
149
150 for (i = current_length - 1; ; --i) {
151 if (i < 0) {
152 done = TRUE;
153 break;
154 }
155 current[i]++;
156 if (current[i] < pieces_lengths[i]) break; // got sequence
157 current[i] = 0;
158 }
159 return buffer;
160 }
161
162 /**
163 *@param set the source string to iterate against. This allows the same iterator to be used
164 * while changing the source string, saving object creation.
165 */
166 void CanonicalIterator::setSource(const UnicodeString &newSource, UErrorCode &status) {
167 int32_t list_length = 0;
168 UChar32 cp = 0;
169 int32_t start = 0;
170 int32_t i = 0;
171 UnicodeString *list = NULL;
172
173 nfd.normalize(newSource, source, status);
174 if(U_FAILURE(status)) {
175 return;
176 }
177 done = FALSE;
178
179 cleanPieces();
180
181 // catch degenerate case
182 if (newSource.length() == 0) {
183 pieces = (UnicodeString **)uprv_malloc(sizeof(UnicodeString *));
184 pieces_lengths = (int32_t*)uprv_malloc(1 * sizeof(int32_t));
185 pieces_length = 1;
186 current = (int32_t*)uprv_malloc(1 * sizeof(int32_t));
187 current_length = 1;
188 if (pieces == NULL || pieces_lengths == NULL || current == NULL) {
189 status = U_MEMORY_ALLOCATION_ERROR;
190 goto CleanPartialInitialization;
191 }
192 current[0] = 0;
193 pieces[0] = new UnicodeString[1];
194 pieces_lengths[0] = 1;
195 if (pieces[0] == 0) {
196 status = U_MEMORY_ALLOCATION_ERROR;
197 goto CleanPartialInitialization;
198 }
199 return;
200 }
201
202
203 list = new UnicodeString[source.length()];
204 if (list == 0) {
205 status = U_MEMORY_ALLOCATION_ERROR;
206 goto CleanPartialInitialization;
207 }
208
209 // i should initialy be the number of code units at the
210 // start of the string
211 i = U16_LENGTH(source.char32At(0));
212 //int32_t i = 1;
213 // find the segments
214 // This code iterates through the source string and
215 // extracts segments that end up on a codepoint that
216 // doesn't start any decompositions. (Analysis is done
217 // on the NFD form - see above).
218 for (; i < source.length(); i += U16_LENGTH(cp)) {
219 cp = source.char32At(i);
220 if (nfcImpl.isCanonSegmentStarter(cp)) {
221 source.extract(start, i-start, list[list_length++]); // add up to i
222 start = i;
223 }
224 }
225 source.extract(start, i-start, list[list_length++]); // add last one
226
227
228 // allocate the arrays, and find the strings that are CE to each segment
229 pieces = (UnicodeString **)uprv_malloc(list_length * sizeof(UnicodeString *));
230 pieces_length = list_length;
231 pieces_lengths = (int32_t*)uprv_malloc(list_length * sizeof(int32_t));
232 current = (int32_t*)uprv_malloc(list_length * sizeof(int32_t));
233 current_length = list_length;
234 if (pieces == NULL || pieces_lengths == NULL || current == NULL) {
235 status = U_MEMORY_ALLOCATION_ERROR;
236 goto CleanPartialInitialization;
237 }
238
239 for (i = 0; i < current_length; i++) {
240 current[i] = 0;
241 }
242 // for each segment, get all the combinations that can produce
243 // it after NFD normalization
244 for (i = 0; i < pieces_length; ++i) {
245 //if (PROGRESS) printf("SEGMENT\n");
246 pieces[i] = getEquivalents(list[i], pieces_lengths[i], status);
247 }
248
249 delete[] list;
250 return;
251 // Common section to cleanup all local variables and reset object variables.
252 CleanPartialInitialization:
253 if (list != NULL) {
254 delete[] list;
255 }
256 cleanPieces();
257 }
258
259 /**
260 * Dumb recursive implementation of permutation.
261 * TODO: optimize
262 * @param source the string to find permutations for
263 * @return the results in a set.
264 */
265 void U_EXPORT2 CanonicalIterator::permute(UnicodeString &source, UBool skipZeros, Hashtable *result, UErrorCode &status) {
266 if(U_FAILURE(status)) {
267 return;
268 }
269 //if (PROGRESS) printf("Permute: %s\n", UToS(Tr(source)));
270 int32_t i = 0;
271
272 // optimization:
273 // if zero or one character, just return a set with it
274 // we check for length < 2 to keep from counting code points all the time
275 if (source.length() <= 2 && source.countChar32() <= 1) {
276 UnicodeString *toPut = new UnicodeString(source);
277 /* test for NULL */
278 if (toPut == 0) {
279 status = U_MEMORY_ALLOCATION_ERROR;
280 return;
281 }
282 result->put(source, toPut, status);
283 return;
284 }
285
286 // otherwise iterate through the string, and recursively permute all the other characters
287 UChar32 cp;
288 Hashtable subpermute(status);
289 if(U_FAILURE(status)) {
290 return;
291 }
292 subpermute.setValueDeleter(uprv_deleteUObject);
293
294 for (i = 0; i < source.length(); i += U16_LENGTH(cp)) {
295 cp = source.char32At(i);
296 const UHashElement *ne = NULL;
297 int32_t el = -1;
298 UnicodeString subPermuteString = source;
299
300 // optimization:
301 // if the character is canonical combining class zero,
302 // don't permute it
303 if (skipZeros && i != 0 && u_getCombiningClass(cp) == 0) {
304 //System.out.println("Skipping " + Utility.hex(UTF16.valueOf(source, i)));
305 continue;
306 }
307
308 subpermute.removeAll();
309
310 // see what the permutations of the characters before and after this one are
311 //Hashtable *subpermute = permute(source.substring(0,i) + source.substring(i + UTF16.getCharCount(cp)));
312 permute(subPermuteString.replace(i, U16_LENGTH(cp), NULL, 0), skipZeros, &subpermute, status);
313 /* Test for buffer overflows */
314 if(U_FAILURE(status)) {
315 return;
316 }
317 // The upper replace is destructive. The question is do we have to make a copy, or we don't care about the contents
318 // of source at this point.
319
320 // prefix this character to all of them
321 ne = subpermute.nextElement(el);
322 while (ne != NULL) {
323 UnicodeString *permRes = (UnicodeString *)(ne->value.pointer);
324 UnicodeString *chStr = new UnicodeString(cp);
325 //test for NULL
326 if (chStr == NULL) {
327 status = U_MEMORY_ALLOCATION_ERROR;
328 return;
329 }
330 chStr->append(*permRes); //*((UnicodeString *)(ne->value.pointer));
331 //if (PROGRESS) printf(" Piece: %s\n", UToS(*chStr));
332 result->put(*chStr, chStr, status);
333 ne = subpermute.nextElement(el);
334 }
335 }
336 //return result;
337 }
338
339 // privates
340
341 // we have a segment, in NFD. Find all the strings that are canonically equivalent to it.
342 UnicodeString* CanonicalIterator::getEquivalents(const UnicodeString &segment, int32_t &result_len, UErrorCode &status) {
343 Hashtable result(status);
344 Hashtable permutations(status);
345 Hashtable basic(status);
346 if (U_FAILURE(status)) {
347 return 0;
348 }
349 result.setValueDeleter(uprv_deleteUObject);
350 permutations.setValueDeleter(uprv_deleteUObject);
351 basic.setValueDeleter(uprv_deleteUObject);
352
353 UChar USeg[256];
354 int32_t segLen = segment.extract(USeg, 256, status);
355 getEquivalents2(&basic, USeg, segLen, status);
356
357 // now get all the permutations
358 // add only the ones that are canonically equivalent
359 // TODO: optimize by not permuting any class zero.
360
361 const UHashElement *ne = NULL;
362 int32_t el = -1;
363 //Iterator it = basic.iterator();
364 ne = basic.nextElement(el);
365 //while (it.hasNext())
366 while (ne != NULL) {
367 //String item = (String) it.next();
368 UnicodeString item = *((UnicodeString *)(ne->value.pointer));
369
370 permutations.removeAll();
371 permute(item, CANITER_SKIP_ZEROES, &permutations, status);
372 const UHashElement *ne2 = NULL;
373 int32_t el2 = -1;
374 //Iterator it2 = permutations.iterator();
375 ne2 = permutations.nextElement(el2);
376 //while (it2.hasNext())
377 while (ne2 != NULL) {
378 //String possible = (String) it2.next();
379 //UnicodeString *possible = new UnicodeString(*((UnicodeString *)(ne2->value.pointer)));
380 UnicodeString possible(*((UnicodeString *)(ne2->value.pointer)));
381 UnicodeString attempt;
382 nfd.normalize(possible, attempt, status);
383
384 // TODO: check if operator == is semanticaly the same as attempt.equals(segment)
385 if (attempt==segment) {
386 //if (PROGRESS) printf("Adding Permutation: %s\n", UToS(Tr(*possible)));
387 // TODO: use the hashtable just to catch duplicates - store strings directly (somehow).
388 result.put(possible, new UnicodeString(possible), status); //add(possible);
389 } else {
390 //if (PROGRESS) printf("-Skipping Permutation: %s\n", UToS(Tr(*possible)));
391 }
392
393 ne2 = permutations.nextElement(el2);
394 }
395 ne = basic.nextElement(el);
396 }
397
398 /* Test for buffer overflows */
399 if(U_FAILURE(status)) {
400 return 0;
401 }
402 // convert into a String[] to clean up storage
403 //String[] finalResult = new String[result.size()];
404 UnicodeString *finalResult = NULL;
405 int32_t resultCount;
406 if((resultCount = result.count())) {
407 finalResult = new UnicodeString[resultCount];
408 if (finalResult == 0) {
409 status = U_MEMORY_ALLOCATION_ERROR;
410 return NULL;
411 }
412 }
413 else {
414 status = U_ILLEGAL_ARGUMENT_ERROR;
415 return NULL;
416 }
417 //result.toArray(finalResult);
418 result_len = 0;
419 el = -1;
420 ne = result.nextElement(el);
421 while(ne != NULL) {
422 finalResult[result_len++] = *((UnicodeString *)(ne->value.pointer));
423 ne = result.nextElement(el);
424 }
425
426
427 return finalResult;
428 }
429
430 Hashtable *CanonicalIterator::getEquivalents2(Hashtable *fillinResult, const UChar *segment, int32_t segLen, UErrorCode &status) {
431
432 if (U_FAILURE(status)) {
433 return NULL;
434 }
435
436 //if (PROGRESS) printf("Adding: %s\n", UToS(Tr(segment)));
437
438 UnicodeString toPut(segment, segLen);
439
440 fillinResult->put(toPut, new UnicodeString(toPut), status);
441
442 UnicodeSet starts;
443
444 // cycle through all the characters
445 UChar32 cp;
446 for (int32_t i = 0; i < segLen; i += U16_LENGTH(cp)) {
447 // see if any character is at the start of some decomposition
448 U16_GET(segment, 0, i, segLen, cp);
449 if (!nfcImpl.getCanonStartSet(cp, starts)) {
450 continue;
451 }
452 // if so, see which decompositions match
453 UnicodeSetIterator iter(starts);
454 while (iter.next()) {
455 UChar32 cp2 = iter.getCodepoint();
456 Hashtable remainder(status);
457 remainder.setValueDeleter(uprv_deleteUObject);
458 if (extract(&remainder, cp2, segment, segLen, i, status) == NULL) {
459 continue;
460 }
461
462 // there were some matches, so add all the possibilities to the set.
463 UnicodeString prefix(segment, i);
464 prefix += cp2;
465
466 int32_t el = -1;
467 const UHashElement *ne = remainder.nextElement(el);
468 while (ne != NULL) {
469 UnicodeString item = *((UnicodeString *)(ne->value.pointer));
470 UnicodeString *toAdd = new UnicodeString(prefix);
471 /* test for NULL */
472 if (toAdd == 0) {
473 status = U_MEMORY_ALLOCATION_ERROR;
474 return NULL;
475 }
476 *toAdd += item;
477 fillinResult->put(*toAdd, toAdd, status);
478
479 //if (PROGRESS) printf("Adding: %s\n", UToS(Tr(*toAdd)));
480
481 ne = remainder.nextElement(el);
482 }
483 }
484 }
485
486 /* Test for buffer overflows */
487 if(U_FAILURE(status)) {
488 return NULL;
489 }
490 return fillinResult;
491 }
492
493 /**
494 * See if the decomposition of cp2 is at segment starting at segmentPos
495 * (with canonical rearrangment!)
496 * If so, take the remainder, and return the equivalents
497 */
498 Hashtable *CanonicalIterator::extract(Hashtable *fillinResult, UChar32 comp, const UChar *segment, int32_t segLen, int32_t segmentPos, UErrorCode &status) {
499 //Hashtable *CanonicalIterator::extract(UChar32 comp, const UnicodeString &segment, int32_t segLen, int32_t segmentPos, UErrorCode &status) {
500 //if (PROGRESS) printf(" extract: %s, ", UToS(Tr(UnicodeString(comp))));
501 //if (PROGRESS) printf("%s, %i\n", UToS(Tr(segment)), segmentPos);
502
503 if (U_FAILURE(status)) {
504 return NULL;
505 }
506
507 UnicodeString temp(comp);
508 int32_t inputLen=temp.length();
509 UnicodeString decompString;
510 nfd.normalize(temp, decompString, status);
511 const UChar *decomp=decompString.getBuffer();
512 int32_t decompLen=decompString.length();
513
514 // See if it matches the start of segment (at segmentPos)
515 UBool ok = FALSE;
516 UChar32 cp;
517 int32_t decompPos = 0;
518 UChar32 decompCp;
519 U16_NEXT(decomp, decompPos, decompLen, decompCp);
520
521 int32_t i = segmentPos;
522 while(i < segLen) {
523 U16_NEXT(segment, i, segLen, cp);
524
525 if (cp == decompCp) { // if equal, eat another cp from decomp
526
527 //if (PROGRESS) printf(" matches: %s\n", UToS(Tr(UnicodeString(cp))));
528
529 if (decompPos == decompLen) { // done, have all decomp characters!
530 temp.append(segment+i, segLen-i);
531 ok = TRUE;
532 break;
533 }
534 U16_NEXT(decomp, decompPos, decompLen, decompCp);
535 } else {
536 //if (PROGRESS) printf(" buffer: %s\n", UToS(Tr(UnicodeString(cp))));
537
538 // brute force approach
539 temp.append(cp);
540
541 /* TODO: optimize
542 // since we know that the classes are monotonically increasing, after zero
543 // e.g. 0 5 7 9 0 3
544 // we can do an optimization
545 // there are only a few cases that work: zero, less, same, greater
546 // if both classes are the same, we fail
547 // if the decomp class < the segment class, we fail
548
549 segClass = getClass(cp);
550 if (decompClass <= segClass) return null;
551 */
552 }
553 }
554 if (!ok)
555 return NULL; // we failed, characters left over
556
557 //if (PROGRESS) printf("Matches\n");
558
559 if (inputLen == temp.length()) {
560 fillinResult->put(UnicodeString(), new UnicodeString(), status);
561 return fillinResult; // succeed, but no remainder
562 }
563
564 // brute force approach
565 // check to make sure result is canonically equivalent
566 UnicodeString trial;
567 nfd.normalize(temp, trial, status);
568 if(U_FAILURE(status) || trial.compare(segment+segmentPos, segLen - segmentPos) != 0) {
569 return NULL;
570 }
571
572 return getEquivalents2(fillinResult, temp.getBuffer()+inputLen, temp.length()-inputLen, status);
573 }
574
575 U_NAMESPACE_END
576
577 #endif /* #if !UCONFIG_NO_NORMALIZATION */

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