icuSources/common/caniter.cpp

   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:
  28 Results for: {LATIN CAPITAL LETTER A WITH RING ABOVE}{LATIN SMALL LETTER D}{COMBINING DOT ABOVE}{COMBINING CEDILLA}
  29 1: \u0041\u030A\u0064\u0307\u0327
  30  = {LATIN CAPITAL LETTER A}{COMBINING RING ABOVE}{LATIN SMALL LETTER D}{COMBINING DOT ABOVE}{COMBINING CEDILLA}
  31 2: \u0041\u030A\u0064\u0327\u0307
  32  = {LATIN CAPITAL LETTER A}{COMBINING RING ABOVE}{LATIN SMALL LETTER D}{COMBINING CEDILLA}{COMBINING DOT ABOVE}
  33 3: \u0041\u030A\u1E0B\u0327
  34  = {LATIN CAPITAL LETTER A}{COMBINING RING ABOVE}{LATIN SMALL LETTER D WITH DOT ABOVE}{COMBINING CEDILLA}
  35 4: \u0041\u030A\u1E11\u0307
  36  = {LATIN CAPITAL LETTER A}{COMBINING RING ABOVE}{LATIN SMALL LETTER D WITH CEDILLA}{COMBINING DOT ABOVE}
  37 5: \u00C5\u0064\u0307\u0327
  38  = {LATIN CAPITAL LETTER A WITH RING ABOVE}{LATIN SMALL LETTER D}{COMBINING DOT ABOVE}{COMBINING CEDILLA}
  39 6: \u00C5\u0064\u0327\u0307
  40  = {LATIN CAPITAL LETTER A WITH RING ABOVE}{LATIN SMALL LETTER D}{COMBINING CEDILLA}{COMBINING DOT ABOVE}
  41 7: \u00C5\u1E0B\u0327
  42  = {LATIN CAPITAL LETTER A WITH RING ABOVE}{LATIN SMALL LETTER D WITH DOT ABOVE}{COMBINING CEDILLA}
  43 8: \u00C5\u1E11\u0307
  44  = {LATIN CAPITAL LETTER A WITH RING ABOVE}{LATIN SMALL LETTER D WITH CEDILLA}{COMBINING DOT ABOVE}
  45 9: \u212B\u0064\u0307\u0327
  46  = {ANGSTROM SIGN}{LATIN SMALL LETTER D}{COMBINING DOT ABOVE}{COMBINING CEDILLA}
  47 10: \u212B\u0064\u0327\u0307
  48  = {ANGSTROM SIGN}{LATIN SMALL LETTER D}{COMBINING CEDILLA}{COMBINING DOT ABOVE}
  49 11: \u212B\u1E0B\u0327
  50  = {ANGSTROM SIGN}{LATIN SMALL LETTER D WITH DOT ABOVE}{COMBINING CEDILLA}
  51 12: \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
  61 U_NAMESPACE_BEGIN
  62
  63 // TODO: add boilerplate methods.
  64
  65 UOBJECT_DEFINE_RTTI_IMPLEMENTATION(CanonicalIterator)
  66
  67 /**
  68  *@param source string to get results for
  69  */
  70 CanonicalIterator::CanonicalIterator(const UnicodeString &sourceStr, UErrorCode &status) :
  71     pieces(NULL),
  72     pieces_length(0),
  73     pieces_lengths(NULL),
  74     current(NULL),
  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
  84 CanonicalIterator::~CanonicalIterator() {
  85   cleanPieces();
  86 }
  87
  88 void CanonicalIterator::cleanPieces() {
  89     int32_t i = 0;
  90     if(pieces != NULL) {
  91         for(i = 0; i < pieces_length; i++) {
  92             if(pieces[i] != NULL) {
  93                 delete[] pieces[i];
  94             }
  95         }
  96         uprv_free(pieces);
  97         pieces = NULL;
  98         pieces_length = 0;
  99     }
 100     if(pieces_lengths != NULL) {
 101         uprv_free(pieces_lengths);
 102         pieces_lengths = NULL;
 103     }
 104     if(current != NULL) {
 105         uprv_free(current);
 106         current = NULL;
 107         current_length = 0;
 108     }
 109 }
 110
 111 /**
 112  *@return gets the source: NOTE: it is the NFD form of source
 113  */
 114 UnicodeString CanonicalIterator::getSource() {
 115   return source;
 116 }
 117
 118 /**
 119  * Resets the iterator so that one can start again from the beginning.
 120  */
 121 void 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  */
 132 UnicodeString 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  */
 168 void 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 = NULL;
 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 == NULL || pieces_lengths == NULL || current == NULL) {
 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 initialy 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 == NULL || pieces_lengths == NULL || current == NULL) {
 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.
 254 CleanPartialInitialization:
 255     if (list != NULL) {
 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  */
 267 void 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 NULL */
 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 = NULL;
 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 != NULL) {
 325             UnicodeString *permRes = (UnicodeString *)(ne->value.pointer);
 326             UnicodeString *chStr = new UnicodeString(cp);
 327             //test for  NULL
 328             if (chStr == NULL) {
 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.
 344 UnicodeString* 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     UChar 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 = NULL;
 364     int32_t el = UHASH_FIRST;
 365     //Iterator it = basic.iterator();
 366     ne = basic.nextElement(el);
 367     //while (it.hasNext())
 368     while (ne != NULL) {
 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 = NULL;
 375         int32_t el2 = UHASH_FIRST;
 376         //Iterator it2 = permutations.iterator();
 377         ne2 = permutations.nextElement(el2);
 378         //while (it2.hasNext())
 379         while (ne2 != NULL) {
 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 = NULL;
 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 NULL;
 413         }
 414     }
 415     else {
 416         status = U_ILLEGAL_ARGUMENT_ERROR;
 417         return NULL;
 418     }
 419     //result.toArray(finalResult);
 420     result_len = 0;
 421     el = UHASH_FIRST;
 422     ne = result.nextElement(el);
 423     while(ne != NULL) {
 424         finalResult[result_len++] = *((UnicodeString *)(ne->value.pointer));
 425         ne = result.nextElement(el);
 426     }
 427
 428
 429     return finalResult;
 430 }
 431
 432 Hashtable *CanonicalIterator::getEquivalents2(Hashtable *fillinResult, const UChar *segment, int32_t segLen, UErrorCode &status) {
 433
 434     if (U_FAILURE(status)) {
 435         return NULL;
 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) == NULL) {
 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 != NULL) {
 471                 UnicodeString item = *((UnicodeString *)(ne->value.pointer));
 472                 UnicodeString *toAdd = new UnicodeString(prefix);
 473                 /* test for NULL */
 474                 if (toAdd == 0) {
 475                     status = U_MEMORY_ALLOCATION_ERROR;
 476                     return NULL;
 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 NULL;
 491     }
 492     return fillinResult;
 493 }
 494
 495 /**
 496  * See if the decomposition of cp2 is at segment starting at segmentPos
 497  * (with canonical rearrangment!)
 498  * If so, take the remainder, and return the equivalents
 499  */
 500 Hashtable *CanonicalIterator::extract(Hashtable *fillinResult, UChar32 comp, const UChar *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 NULL;
 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 NULL;
 515     }
 516     if (decompString.isBogus()) {
 517         status = U_MEMORY_ALLOCATION_ERROR;
 518         return NULL;
 519     }
 520     const UChar *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 NULL; // 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 NULL;
 579     }
 580
 581     return getEquivalents2(fillinResult, temp.getBuffer()+inputLen, temp.length()-inputLen, status);
 582 }
 583
 584 U_NAMESPACE_END
 585
 586 #endif /* #if !UCONFIG_NO_NORMALIZATION */