1// © 2016 and later: Unicode, Inc. and others.
2// License & terms of use: http://www.unicode.org/copyright.html
3/*
4 *****************************************************************************
5 * Copyright (C) 1996-2015, International Business Machines Corporation and
6 * others. All Rights Reserved.
7 *****************************************************************************
8 */
9
10#include "unicode/utypes.h"
11
12#if !UCONFIG_NO_NORMALIZATION
13
14#include "unicode/caniter.h"
15#include "unicode/normalizer2.h"
16#include "unicode/uchar.h"
17#include "unicode/uniset.h"
18#include "unicode/usetiter.h"
19#include "unicode/ustring.h"
20#include "unicode/utf16.h"
21#include "cmemory.h"
22#include "hash.h"
23#include "normalizer2impl.h"
24
25/**
26 * This class allows one to iterate through all the strings that are canonically equivalent to a given
27 * string. For example, here are some sample results:
28Results for: {LATIN CAPITAL LETTER A WITH RING ABOVE}{LATIN SMALL LETTER D}{COMBINING DOT ABOVE}{COMBINING CEDILLA}
291: \u0041\u030A\u0064\u0307\u0327
30 = {LATIN CAPITAL LETTER A}{COMBINING RING ABOVE}{LATIN SMALL LETTER D}{COMBINING DOT ABOVE}{COMBINING CEDILLA}
312: \u0041\u030A\u0064\u0327\u0307
32 = {LATIN CAPITAL LETTER A}{COMBINING RING ABOVE}{LATIN SMALL LETTER D}{COMBINING CEDILLA}{COMBINING DOT ABOVE}
333: \u0041\u030A\u1E0B\u0327
34 = {LATIN CAPITAL LETTER A}{COMBINING RING ABOVE}{LATIN SMALL LETTER D WITH DOT ABOVE}{COMBINING CEDILLA}
354: \u0041\u030A\u1E11\u0307
36 = {LATIN CAPITAL LETTER A}{COMBINING RING ABOVE}{LATIN SMALL LETTER D WITH CEDILLA}{COMBINING DOT ABOVE}
375: \u00C5\u0064\u0307\u0327
38 = {LATIN CAPITAL LETTER A WITH RING ABOVE}{LATIN SMALL LETTER D}{COMBINING DOT ABOVE}{COMBINING CEDILLA}
396: \u00C5\u0064\u0327\u0307
40 = {LATIN CAPITAL LETTER A WITH RING ABOVE}{LATIN SMALL LETTER D}{COMBINING CEDILLA}{COMBINING DOT ABOVE}
417: \u00C5\u1E0B\u0327
42 = {LATIN CAPITAL LETTER A WITH RING ABOVE}{LATIN SMALL LETTER D WITH DOT ABOVE}{COMBINING CEDILLA}
438: \u00C5\u1E11\u0307
44 = {LATIN CAPITAL LETTER A WITH RING ABOVE}{LATIN SMALL LETTER D WITH CEDILLA}{COMBINING DOT ABOVE}
459: \u212B\u0064\u0307\u0327
46 = {ANGSTROM SIGN}{LATIN SMALL LETTER D}{COMBINING DOT ABOVE}{COMBINING CEDILLA}
4710: \u212B\u0064\u0327\u0307
48 = {ANGSTROM SIGN}{LATIN SMALL LETTER D}{COMBINING CEDILLA}{COMBINING DOT ABOVE}
4911: \u212B\u1E0B\u0327
50 = {ANGSTROM SIGN}{LATIN SMALL LETTER D WITH DOT ABOVE}{COMBINING CEDILLA}
5112: \u212B\u1E11\u0307
52 = {ANGSTROM SIGN}{LATIN SMALL LETTER D WITH CEDILLA}{COMBINING DOT ABOVE}
53 *<br>Note: the code is intended for use with small strings, and is not suitable for larger ones,
54 * since it has not been optimized for that situation.
55 *@author M. Davis
56 *@draft
57 */
58
59// public
60
61U_NAMESPACE_BEGIN
62
63// TODO: add boilerplate methods.
64
65UOBJECT_DEFINE_RTTI_IMPLEMENTATION(CanonicalIterator)
66
67/**
68 *@param source string to get results for
69 */
70CanonicalIterator::CanonicalIterator(const UnicodeString &sourceStr, UErrorCode &status) :
71 pieces(nullptr),
72 pieces_length(0),
73 pieces_lengths(nullptr),
74 current(nullptr),
75 current_length(0),
76 nfd(*Normalizer2::getNFDInstance(status)),
77 nfcImpl(*Normalizer2Factory::getNFCImpl(status))
78{
79 if(U_SUCCESS(status) && nfcImpl.ensureCanonIterData(status)) {
80 setSource(sourceStr, status);
81 }
82}
83
84CanonicalIterator::~CanonicalIterator() {
85 cleanPieces();
86}
87
88void CanonicalIterator::cleanPieces() {
89 int32_t i = 0;
90 if(pieces != nullptr) {
91 for(i = 0; i < pieces_length; i++) {
92 if(pieces[i] != nullptr) {
93 delete[] pieces[i];
94 }
95 }
96 uprv_free(pieces);
97 pieces = nullptr;
98 pieces_length = 0;
99 }
100 if(pieces_lengths != nullptr) {
101 uprv_free(pieces_lengths);
102 pieces_lengths = nullptr;
103 }
104 if(current != nullptr) {
105 uprv_free(current);
106 current = nullptr;
107 current_length = 0;
108 }
109}
110
111/**
112 *@return gets the source: NOTE: it is the NFD form of source
113 */
114UnicodeString CanonicalIterator::getSource() {
115 return source;
116}
117
118/**
119 * Resets the iterator so that one can start again from the beginning.
120 */
121void CanonicalIterator::reset() {
122 done = false;
123 for (int i = 0; i < current_length; ++i) {
124 current[i] = 0;
125 }
126}
127
128/**
129 *@return the next string that is canonically equivalent. The value null is returned when
130 * the iteration is done.
131 */
132UnicodeString CanonicalIterator::next() {
133 int32_t i = 0;
134
135 if (done) {
136 buffer.setToBogus();
137 return buffer;
138 }
139
140 // delete old contents
141 buffer.remove();
142
143 // construct return value
144
145 for (i = 0; i < pieces_length; ++i) {
146 buffer.append(pieces[i][current[i]]);
147 }
148 //String result = buffer.toString(); // not needed
149
150 // find next value for next time
151
152 for (i = current_length - 1; ; --i) {
153 if (i < 0) {
154 done = true;
155 break;
156 }
157 current[i]++;
158 if (current[i] < pieces_lengths[i]) break; // got sequence
159 current[i] = 0;
160 }
161 return buffer;
162}
163
164/**
165 *@param set the source string to iterate against. This allows the same iterator to be used
166 * while changing the source string, saving object creation.
167 */
168void CanonicalIterator::setSource(const UnicodeString &newSource, UErrorCode &status) {
169 int32_t list_length = 0;
170 UChar32 cp = 0;
171 int32_t start = 0;
172 int32_t i = 0;
173 UnicodeString *list = nullptr;
174
175 nfd.normalize(newSource, source, status);
176 if(U_FAILURE(status)) {
177 return;
178 }
179 done = false;
180
181 cleanPieces();
182
183 // catch degenerate case
184 if (newSource.length() == 0) {
185 pieces = (UnicodeString **)uprv_malloc(sizeof(UnicodeString *));
186 pieces_lengths = (int32_t*)uprv_malloc(1 * sizeof(int32_t));
187 pieces_length = 1;
188 current = (int32_t*)uprv_malloc(1 * sizeof(int32_t));
189 current_length = 1;
190 if (pieces == nullptr || pieces_lengths == nullptr || current == nullptr) {
191 status = U_MEMORY_ALLOCATION_ERROR;
192 goto CleanPartialInitialization;
193 }
194 current[0] = 0;
195 pieces[0] = new UnicodeString[1];
196 pieces_lengths[0] = 1;
197 if (pieces[0] == 0) {
198 status = U_MEMORY_ALLOCATION_ERROR;
199 goto CleanPartialInitialization;
200 }
201 return;
202 }
203
204
205 list = new UnicodeString[source.length()];
206 if (list == 0) {
207 status = U_MEMORY_ALLOCATION_ERROR;
208 goto CleanPartialInitialization;
209 }
210
211 // i should initially be the number of code units at the
212 // start of the string
213 i = U16_LENGTH(source.char32At(0));
214 // int32_t i = 1;
215 // find the segments
216 // This code iterates through the source string and
217 // extracts segments that end up on a codepoint that
218 // doesn't start any decompositions. (Analysis is done
219 // on the NFD form - see above).
220 for (; i < source.length(); i += U16_LENGTH(cp)) {
221 cp = source.char32At(i);
222 if (nfcImpl.isCanonSegmentStarter(cp)) {
223 source.extract(start, i-start, list[list_length++]); // add up to i
224 start = i;
225 }
226 }
227 source.extract(start, i-start, list[list_length++]); // add last one
228
229
230 // allocate the arrays, and find the strings that are CE to each segment
231 pieces = (UnicodeString **)uprv_malloc(list_length * sizeof(UnicodeString *));
232 pieces_length = list_length;
233 pieces_lengths = (int32_t*)uprv_malloc(list_length * sizeof(int32_t));
234 current = (int32_t*)uprv_malloc(list_length * sizeof(int32_t));
235 current_length = list_length;
236 if (pieces == nullptr || pieces_lengths == nullptr || current == nullptr) {
237 status = U_MEMORY_ALLOCATION_ERROR;
238 goto CleanPartialInitialization;
239 }
240
241 for (i = 0; i < current_length; i++) {
242 current[i] = 0;
243 }
244 // for each segment, get all the combinations that can produce
245 // it after NFD normalization
246 for (i = 0; i < pieces_length; ++i) {
247 //if (PROGRESS) printf("SEGMENT\n");
248 pieces[i] = getEquivalents(list[i], pieces_lengths[i], status);
249 }
250
251 delete[] list;
252 return;
253// Common section to cleanup all local variables and reset object variables.
254CleanPartialInitialization:
255 if (list != nullptr) {
256 delete[] list;
257 }
258 cleanPieces();
259}
260
261/**
262 * Dumb recursive implementation of permutation.
263 * TODO: optimize
264 * @param source the string to find permutations for
265 * @return the results in a set.
266 */
267void U_EXPORT2 CanonicalIterator::permute(UnicodeString &source, UBool skipZeros, Hashtable *result, UErrorCode &status) {
268 if(U_FAILURE(status)) {
269 return;
270 }
271 //if (PROGRESS) printf("Permute: %s\n", UToS(Tr(source)));
272 int32_t i = 0;
273
274 // optimization:
275 // if zero or one character, just return a set with it
276 // we check for length < 2 to keep from counting code points all the time
277 if (source.length() <= 2 && source.countChar32() <= 1) {
278 UnicodeString *toPut = new UnicodeString(source);
279 /* test for nullptr */
280 if (toPut == 0) {
281 status = U_MEMORY_ALLOCATION_ERROR;
282 return;
283 }
284 result->put(source, toPut, status);
285 return;
286 }
287
288 // otherwise iterate through the string, and recursively permute all the other characters
289 UChar32 cp;
290 Hashtable subpermute(status);
291 if(U_FAILURE(status)) {
292 return;
293 }
294 subpermute.setValueDeleter(uprv_deleteUObject);
295
296 for (i = 0; i < source.length(); i += U16_LENGTH(cp)) {
297 cp = source.char32At(i);
298 const UHashElement *ne = nullptr;
299 int32_t el = UHASH_FIRST;
300 UnicodeString subPermuteString = source;
301
302 // optimization:
303 // if the character is canonical combining class zero,
304 // don't permute it
305 if (skipZeros && i != 0 && u_getCombiningClass(cp) == 0) {
306 //System.out.println("Skipping " + Utility.hex(UTF16.valueOf(source, i)));
307 continue;
308 }
309
310 subpermute.removeAll();
311
312 // see what the permutations of the characters before and after this one are
313 //Hashtable *subpermute = permute(source.substring(0,i) + source.substring(i + UTF16.getCharCount(cp)));
314 permute(subPermuteString.remove(i, U16_LENGTH(cp)), skipZeros, &subpermute, status);
315 /* Test for buffer overflows */
316 if(U_FAILURE(status)) {
317 return;
318 }
319 // The upper remove is destructive. The question is do we have to make a copy, or we don't care about the contents
320 // of source at this point.
321
322 // prefix this character to all of them
323 ne = subpermute.nextElement(el);
324 while (ne != nullptr) {
325 UnicodeString *permRes = (UnicodeString *)(ne->value.pointer);
326 UnicodeString *chStr = new UnicodeString(cp);
327 //test for nullptr
328 if (chStr == nullptr) {
329 status = U_MEMORY_ALLOCATION_ERROR;
330 return;
331 }
332 chStr->append(*permRes); //*((UnicodeString *)(ne->value.pointer));
333 //if (PROGRESS) printf(" Piece: %s\n", UToS(*chStr));
334 result->put(*chStr, chStr, status);
335 ne = subpermute.nextElement(el);
336 }
337 }
338 //return result;
339}
340
341// privates
342
343// we have a segment, in NFD. Find all the strings that are canonically equivalent to it.
344UnicodeString* CanonicalIterator::getEquivalents(const UnicodeString &segment, int32_t &result_len, UErrorCode &status) {
345 Hashtable result(status);
346 Hashtable permutations(status);
347 Hashtable basic(status);
348 if (U_FAILURE(status)) {
349 return 0;
350 }
351 result.setValueDeleter(uprv_deleteUObject);
352 permutations.setValueDeleter(uprv_deleteUObject);
353 basic.setValueDeleter(uprv_deleteUObject);
354
355 char16_t USeg[256];
356 int32_t segLen = segment.extract(USeg, 256, status);
357 getEquivalents2(&basic, USeg, segLen, status);
358
359 // now get all the permutations
360 // add only the ones that are canonically equivalent
361 // TODO: optimize by not permuting any class zero.
362
363 const UHashElement *ne = nullptr;
364 int32_t el = UHASH_FIRST;
365 //Iterator it = basic.iterator();
366 ne = basic.nextElement(el);
367 //while (it.hasNext())
368 while (ne != nullptr) {
369 //String item = (String) it.next();
370 UnicodeString item = *((UnicodeString *)(ne->value.pointer));
371
372 permutations.removeAll();
373 permute(item, CANITER_SKIP_ZEROES, &permutations, status);
374 const UHashElement *ne2 = nullptr;
375 int32_t el2 = UHASH_FIRST;
376 //Iterator it2 = permutations.iterator();
377 ne2 = permutations.nextElement(el2);
378 //while (it2.hasNext())
379 while (ne2 != nullptr) {
380 //String possible = (String) it2.next();
381 //UnicodeString *possible = new UnicodeString(*((UnicodeString *)(ne2->value.pointer)));
382 UnicodeString possible(*((UnicodeString *)(ne2->value.pointer)));
383 UnicodeString attempt;
384 nfd.normalize(possible, attempt, status);
385
386 // TODO: check if operator == is semanticaly the same as attempt.equals(segment)
387 if (attempt==segment) {
388 //if (PROGRESS) printf("Adding Permutation: %s\n", UToS(Tr(*possible)));
389 // TODO: use the hashtable just to catch duplicates - store strings directly (somehow).
390 result.put(possible, new UnicodeString(possible), status); //add(possible);
391 } else {
392 //if (PROGRESS) printf("-Skipping Permutation: %s\n", UToS(Tr(*possible)));
393 }
394
395 ne2 = permutations.nextElement(el2);
396 }
397 ne = basic.nextElement(el);
398 }
399
400 /* Test for buffer overflows */
401 if(U_FAILURE(status)) {
402 return 0;
403 }
404 // convert into a String[] to clean up storage
405 //String[] finalResult = new String[result.size()];
406 UnicodeString *finalResult = nullptr;
407 int32_t resultCount;
408 if((resultCount = result.count()) != 0) {
409 finalResult = new UnicodeString[resultCount];
410 if (finalResult == 0) {
411 status = U_MEMORY_ALLOCATION_ERROR;
412 return nullptr;
413 }
414 }
415 else {
416 status = U_ILLEGAL_ARGUMENT_ERROR;
417 return nullptr;
418 }
419 //result.toArray(finalResult);
420 result_len = 0;
421 el = UHASH_FIRST;
422 ne = result.nextElement(el);
423 while(ne != nullptr) {
424 finalResult[result_len++] = *((UnicodeString *)(ne->value.pointer));
425 ne = result.nextElement(el);
426 }
427
428
429 return finalResult;
430}
431
432Hashtable *CanonicalIterator::getEquivalents2(Hashtable *fillinResult, const char16_t *segment, int32_t segLen, UErrorCode &status) {
433
434 if (U_FAILURE(status)) {
435 return nullptr;
436 }
437
438 //if (PROGRESS) printf("Adding: %s\n", UToS(Tr(segment)));
439
440 UnicodeString toPut(segment, segLen);
441
442 fillinResult->put(toPut, new UnicodeString(toPut), status);
443
444 UnicodeSet starts;
445
446 // cycle through all the characters
447 UChar32 cp;
448 for (int32_t i = 0; i < segLen; i += U16_LENGTH(cp)) {
449 // see if any character is at the start of some decomposition
450 U16_GET(segment, 0, i, segLen, cp);
451 if (!nfcImpl.getCanonStartSet(cp, starts)) {
452 continue;
453 }
454 // if so, see which decompositions match
455 UnicodeSetIterator iter(starts);
456 while (iter.next()) {
457 UChar32 cp2 = iter.getCodepoint();
458 Hashtable remainder(status);
459 remainder.setValueDeleter(uprv_deleteUObject);
460 if (extract(&remainder, cp2, segment, segLen, i, status) == nullptr) {
461 continue;
462 }
463
464 // there were some matches, so add all the possibilities to the set.
465 UnicodeString prefix(segment, i);
466 prefix += cp2;
467
468 int32_t el = UHASH_FIRST;
469 const UHashElement *ne = remainder.nextElement(el);
470 while (ne != nullptr) {
471 UnicodeString item = *((UnicodeString *)(ne->value.pointer));
472 UnicodeString *toAdd = new UnicodeString(prefix);
473 /* test for nullptr */
474 if (toAdd == 0) {
475 status = U_MEMORY_ALLOCATION_ERROR;
476 return nullptr;
477 }
478 *toAdd += item;
479 fillinResult->put(*toAdd, toAdd, status);
480
481 //if (PROGRESS) printf("Adding: %s\n", UToS(Tr(*toAdd)));
482
483 ne = remainder.nextElement(el);
484 }
485 }
486 }
487
488 /* Test for buffer overflows */
489 if(U_FAILURE(status)) {
490 return nullptr;
491 }
492 return fillinResult;
493}
494
495/**
496 * See if the decomposition of cp2 is at segment starting at segmentPos
497 * (with canonical rearrangement!)
498 * If so, take the remainder, and return the equivalents
499 */
500Hashtable *CanonicalIterator::extract(Hashtable *fillinResult, UChar32 comp, const char16_t *segment, int32_t segLen, int32_t segmentPos, UErrorCode &status) {
501//Hashtable *CanonicalIterator::extract(UChar32 comp, const UnicodeString &segment, int32_t segLen, int32_t segmentPos, UErrorCode &status) {
502 //if (PROGRESS) printf(" extract: %s, ", UToS(Tr(UnicodeString(comp))));
503 //if (PROGRESS) printf("%s, %i\n", UToS(Tr(segment)), segmentPos);
504
505 if (U_FAILURE(status)) {
506 return nullptr;
507 }
508
509 UnicodeString temp(comp);
510 int32_t inputLen=temp.length();
511 UnicodeString decompString;
512 nfd.normalize(temp, decompString, status);
513 if (U_FAILURE(status)) {
514 return nullptr;
515 }
516 if (decompString.isBogus()) {
517 status = U_MEMORY_ALLOCATION_ERROR;
518 return nullptr;
519 }
520 const char16_t *decomp=decompString.getBuffer();
521 int32_t decompLen=decompString.length();
522
523 // See if it matches the start of segment (at segmentPos)
524 UBool ok = false;
525 UChar32 cp;
526 int32_t decompPos = 0;
527 UChar32 decompCp;
528 U16_NEXT(decomp, decompPos, decompLen, decompCp);
529
530 int32_t i = segmentPos;
531 while(i < segLen) {
532 U16_NEXT(segment, i, segLen, cp);
533
534 if (cp == decompCp) { // if equal, eat another cp from decomp
535
536 //if (PROGRESS) printf(" matches: %s\n", UToS(Tr(UnicodeString(cp))));
537
538 if (decompPos == decompLen) { // done, have all decomp characters!
539 temp.append(segment+i, segLen-i);
540 ok = true;
541 break;
542 }
543 U16_NEXT(decomp, decompPos, decompLen, decompCp);
544 } else {
545 //if (PROGRESS) printf(" buffer: %s\n", UToS(Tr(UnicodeString(cp))));
546
547 // brute force approach
548 temp.append(cp);
549
550 /* TODO: optimize
551 // since we know that the classes are monotonically increasing, after zero
552 // e.g. 0 5 7 9 0 3
553 // we can do an optimization
554 // there are only a few cases that work: zero, less, same, greater
555 // if both classes are the same, we fail
556 // if the decomp class < the segment class, we fail
557
558 segClass = getClass(cp);
559 if (decompClass <= segClass) return null;
560 */
561 }
562 }
563 if (!ok)
564 return nullptr; // we failed, characters left over
565
566 //if (PROGRESS) printf("Matches\n");
567
568 if (inputLen == temp.length()) {
569 fillinResult->put(UnicodeString(), new UnicodeString(), status);
570 return fillinResult; // succeed, but no remainder
571 }
572
573 // brute force approach
574 // check to make sure result is canonically equivalent
575 UnicodeString trial;
576 nfd.normalize(temp, trial, status);
577 if(U_FAILURE(status) || trial.compare(segment+segmentPos, segLen - segmentPos) != 0) {
578 return nullptr;
579 }
580
581 return getEquivalents2(fillinResult, temp.getBuffer()+inputLen, temp.length()-inputLen, status);
582}
583
584U_NAMESPACE_END
585
586#endif /* #if !UCONFIG_NO_NORMALIZATION */
587