icuSources/i18n/collationdatabuilder.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) 2012-2015, International Business Machines
   6 * Corporation and others.  All Rights Reserved.
   7 *******************************************************************************
   8 * collationdatabuilder.cpp
   9 *
  10 * (replaced the former ucol_elm.cpp)
  11 *
  12 * created on: 2012apr01
  13 * created by: Markus W. Scherer
  14 */
  15
  16 #include "unicode/utypes.h"
  17
  18 #if !UCONFIG_NO_COLLATION
  19
  20 #include "unicode/localpointer.h"
  21 #include "unicode/uchar.h"
  22 #include "unicode/ucharstrie.h"
  23 #include "unicode/ucharstriebuilder.h"
  24 #include "unicode/uniset.h"
  25 #include "unicode/unistr.h"
  26 #include "unicode/usetiter.h"
  27 #include "unicode/utf16.h"
  28 #include "cmemory.h"
  29 #include "collation.h"
  30 #include "collationdata.h"
  31 #include "collationdatabuilder.h"
  32 #include "collationfastlatinbuilder.h"
  33 #include "collationiterator.h"
  34 #include "normalizer2impl.h"
  35 #include "utrie2.h"
  36 #include "uvectr32.h"
  37 #include "uvectr64.h"
  38 #include "uvector.h"
  39
  40 U_NAMESPACE_BEGIN
  41
  42 CollationDataBuilder::CEModifier::~CEModifier() {}
  43
  44 /**
  45  * Build-time context and CE32 for a code point.
  46  * If a code point has contextual mappings, then the default (no-context) mapping
  47  * and all conditional mappings are stored in a singly-linked list
  48  * of ConditionalCE32, sorted by context strings.
  49  *
  50  * Context strings sort by prefix length, then by prefix, then by contraction suffix.
  51  * Context strings must be unique and in ascending order.
  52  */
  53 struct ConditionalCE32 : public UMemory {
  54     ConditionalCE32()
  55             : context(),
  56               ce32(0), defaultCE32(Collation::NO_CE32), builtCE32(Collation::NO_CE32),
  57               next(-1) {}
  58     ConditionalCE32(const UnicodeString &ct, uint32_t ce)
  59             : context(ct),
  60               ce32(ce), defaultCE32(Collation::NO_CE32), builtCE32(Collation::NO_CE32),
  61               next(-1) {}
  62
  63     inline UBool hasContext() const { return context.length() > 1; }
  64     inline int32_t prefixLength() const { return context.charAt(0); }
  65
  66     /**
  67      * "\0" for the first entry for any code point, with its default CE32.
  68      *
  69      * Otherwise one unit with the length of the prefix string,
  70      * then the prefix string, then the contraction suffix.
  71      */
  72     UnicodeString context;
  73     /**
  74      * CE32 for the code point and its context.
  75      * Can be special (e.g., for an expansion) but not contextual (prefix or contraction tag).
  76      */
  77     uint32_t ce32;
  78     /**
  79      * Default CE32 for all contexts with this same prefix.
  80      * Initially NO_CE32. Set only while building runtime data structures,
  81      * and only on one of the nodes of a sub-list with the same prefix.
  82      */
  83     uint32_t defaultCE32;
  84     /**
  85      * CE32 for the built contexts.
  86      * When fetching CEs from the builder, the contexts are built into their runtime form
  87      * so that the normal collation implementation can process them.
  88      * The result is cached in the list head. It is reset when the contexts are modified.
  89      */
  90     uint32_t builtCE32;
  91     /**
  92      * Index of the next ConditionalCE32.
  93      * Negative for the end of the list.
  94      */
  95     int32_t next;
  96 };
  97
  98 U_CDECL_BEGIN
  99
 100 U_CAPI void U_CALLCONV
 101 uprv_deleteConditionalCE32(void *obj) {
 102     delete static_cast<ConditionalCE32 *>(obj);
 103 }
 104
 105 U_CDECL_END
 106
 107 /**
 108  * Build-time collation element and character iterator.
 109  * Uses the runtime CollationIterator for fetching CEs for a string
 110  * but reads from the builder's unfinished data structures.
 111  * In particular, this class reads from the unfinished trie
 112  * and has to avoid CollationIterator::nextCE() and redirect other
 113  * calls to data->getCE32() and data->getCE32FromSupplementary().
 114  *
 115  * We do this so that we need not implement the collation algorithm
 116  * again for the builder and make it behave exactly like the runtime code.
 117  * That would be more difficult to test and maintain than this indirection.
 118  *
 119  * Some CE32 tags (for example, the DIGIT_TAG) do not occur in the builder data,
 120  * so the data accesses from those code paths need not be modified.
 121  *
 122  * This class iterates directly over whole code points
 123  * so that the CollationIterator does not need the finished trie
 124  * for handling the LEAD_SURROGATE_TAG.
 125  */
 126 class DataBuilderCollationIterator : public CollationIterator {
 127 public:
 128     DataBuilderCollationIterator(CollationDataBuilder &b);
 129
 130     virtual ~DataBuilderCollationIterator();
 131
 132     int32_t fetchCEs(const UnicodeString &str, int32_t start, int64_t ces[], int32_t cesLength);
 133
 134     virtual void resetToOffset(int32_t newOffset);
 135     virtual int32_t getOffset() const;
 136
 137     virtual UChar32 nextCodePoint(UErrorCode &errorCode);
 138     virtual UChar32 previousCodePoint(UErrorCode &errorCode);
 139
 140 protected:
 141     virtual void forwardNumCodePoints(int32_t num, UErrorCode &errorCode);
 142     virtual void backwardNumCodePoints(int32_t num, UErrorCode &errorCode);
 143
 144     virtual uint32_t getDataCE32(UChar32 c) const;
 145     virtual uint32_t getCE32FromBuilderData(uint32_t ce32, UErrorCode &errorCode);
 146
 147     CollationDataBuilder &builder;
 148     CollationData builderData;
 149     uint32_t jamoCE32s[CollationData::JAMO_CE32S_LENGTH];
 150     const UnicodeString *s;
 151     int32_t pos;
 152 };
 153
 154 DataBuilderCollationIterator::DataBuilderCollationIterator(CollationDataBuilder &b)
 155         : CollationIterator(&builderData, /*numeric=*/ FALSE),
 156           builder(b), builderData(b.nfcImpl),
 157           s(NULL), pos(0) {
 158     builderData.base = builder.base;
 159     // Set all of the jamoCE32s[] to indirection CE32s.
 160     for(int32_t j = 0; j < CollationData::JAMO_CE32S_LENGTH; ++j) {  // Count across Jamo types.
 161         UChar32 jamo = CollationDataBuilder::jamoCpFromIndex(j);
 162         jamoCE32s[j] = Collation::makeCE32FromTagAndIndex(Collation::BUILDER_DATA_TAG, jamo) |
 163                 CollationDataBuilder::IS_BUILDER_JAMO_CE32;
 164     }
 165     builderData.jamoCE32s = jamoCE32s;
 166 }
 167
 168 DataBuilderCollationIterator::~DataBuilderCollationIterator() {}
 169
 170 int32_t
 171 DataBuilderCollationIterator::fetchCEs(const UnicodeString &str, int32_t start,
 172                                        int64_t ces[], int32_t cesLength) {
 173     // Set the pointers each time, in case they changed due to reallocation.
 174     builderData.ce32s = reinterpret_cast<const uint32_t *>(builder.ce32s.getBuffer());
 175     builderData.ces = builder.ce64s.getBuffer();
 176     builderData.contexts = builder.contexts.getBuffer();
 177     // Modified copy of CollationIterator::nextCE() and CollationIterator::nextCEFromCE32().
 178     reset();
 179     s = &str;
 180     pos = start;
 181     UErrorCode errorCode = U_ZERO_ERROR;
 182     while(U_SUCCESS(errorCode) && pos < s->length()) {
 183         // No need to keep all CEs in the iterator buffer.
 184         clearCEs();
 185         UChar32 c = s->char32At(pos);
 186         pos += U16_LENGTH(c);
 187         uint32_t ce32 = utrie2_get32(builder.trie, c);
 188         const CollationData *d;
 189         if(ce32 == Collation::FALLBACK_CE32) {
 190             d = builder.base;
 191             ce32 = builder.base->getCE32(c);
 192         } else {
 193             d = &builderData;
 194         }
 195         appendCEsFromCE32(d, c, ce32, /*forward=*/ TRUE, errorCode);
 196         U_ASSERT(U_SUCCESS(errorCode));
 197         for(int32_t i = 0; i < getCEsLength(); ++i) {
 198             int64_t ce = getCE(i);
 199             if(ce != 0) {
 200                 if(cesLength < Collation::MAX_EXPANSION_LENGTH) {
 201                     ces[cesLength] = ce;
 202                 }
 203                 ++cesLength;
 204             }
 205         }
 206     }
 207     return cesLength;
 208 }
 209
 210 void
 211 DataBuilderCollationIterator::resetToOffset(int32_t newOffset) {
 212     reset();
 213     pos = newOffset;
 214 }
 215
 216 int32_t
 217 DataBuilderCollationIterator::getOffset() const {
 218     return pos;
 219 }
 220
 221 UChar32
 222 DataBuilderCollationIterator::nextCodePoint(UErrorCode & /*errorCode*/) {
 223     if(pos == s->length()) {
 224         return U_SENTINEL;
 225     }
 226     UChar32 c = s->char32At(pos);
 227     pos += U16_LENGTH(c);
 228     return c;
 229 }
 230
 231 UChar32
 232 DataBuilderCollationIterator::previousCodePoint(UErrorCode & /*errorCode*/) {
 233     if(pos == 0) {
 234         return U_SENTINEL;
 235     }
 236     UChar32 c = s->char32At(pos - 1);
 237     pos -= U16_LENGTH(c);
 238     return c;
 239 }
 240
 241 void
 242 DataBuilderCollationIterator::forwardNumCodePoints(int32_t num, UErrorCode & /*errorCode*/) {
 243     pos = s->moveIndex32(pos, num);
 244 }
 245
 246 void
 247 DataBuilderCollationIterator::backwardNumCodePoints(int32_t num, UErrorCode & /*errorCode*/) {
 248     pos = s->moveIndex32(pos, -num);
 249 }
 250
 251 uint32_t
 252 DataBuilderCollationIterator::getDataCE32(UChar32 c) const {
 253     return utrie2_get32(builder.trie, c);
 254 }
 255
 256 uint32_t
 257 DataBuilderCollationIterator::getCE32FromBuilderData(uint32_t ce32, UErrorCode &errorCode) {
 258     U_ASSERT(Collation::hasCE32Tag(ce32, Collation::BUILDER_DATA_TAG));
 259     if((ce32 & CollationDataBuilder::IS_BUILDER_JAMO_CE32) != 0) {
 260         UChar32 jamo = Collation::indexFromCE32(ce32);
 261         return utrie2_get32(builder.trie, jamo);
 262     } else {
 263         ConditionalCE32 *cond = builder.getConditionalCE32ForCE32(ce32);
 264         if(cond->builtCE32 == Collation::NO_CE32) {
 265             // Build the context-sensitive mappings into their runtime form and cache the result.
 266             cond->builtCE32 = builder.buildContext(cond, errorCode);
 267             if(errorCode == U_BUFFER_OVERFLOW_ERROR) {
 268                 errorCode = U_ZERO_ERROR;
 269                 builder.clearContexts();
 270                 cond->builtCE32 = builder.buildContext(cond, errorCode);
 271             }
 272             builderData.contexts = builder.contexts.getBuffer();
 273         }
 274         return cond->builtCE32;
 275     }
 276 }
 277
 278 // ------------------------------------------------------------------------- ***
 279
 280 CollationDataBuilder::CollationDataBuilder(UErrorCode &errorCode)
 281         : nfcImpl(*Normalizer2Factory::getNFCImpl(errorCode)),
 282           base(NULL), baseSettings(NULL),
 283           trie(NULL),
 284           ce32s(errorCode), ce64s(errorCode), conditionalCE32s(errorCode),
 285           modified(FALSE),
 286           fastLatinEnabled(FALSE), fastLatinBuilder(NULL),
 287           collIter(NULL) {
 288     // Reserve the first CE32 for U+0000.
 289     ce32s.addElement(0, errorCode);
 290     conditionalCE32s.setDeleter(uprv_deleteConditionalCE32);
 291 }
 292
 293 CollationDataBuilder::~CollationDataBuilder() {
 294     utrie2_close(trie);
 295     delete fastLatinBuilder;
 296     delete collIter;
 297 }
 298
 299 void
 300 CollationDataBuilder::initForTailoring(const CollationData *b, UErrorCode &errorCode) {
 301     if(U_FAILURE(errorCode)) { return; }
 302     if(trie != NULL) {
 303         errorCode = U_INVALID_STATE_ERROR;
 304         return;
 305     }
 306     if(b == NULL) {
 307         errorCode = U_ILLEGAL_ARGUMENT_ERROR;
 308         return;
 309     }
 310     base = b;
 311
 312     // For a tailoring, the default is to fall back to the base.
 313     trie = utrie2_open(Collation::FALLBACK_CE32, Collation::FFFD_CE32, &errorCode);
 314
 315     // Set the Latin-1 letters block so that it is allocated first in the data array,
 316     // to try to improve locality of reference when sorting Latin-1 text.
 317     // Do not use utrie2_setRange32() since that will not actually allocate blocks
 318     // that are filled with the default value.
 319     // ASCII (0..7F) is already preallocated anyway.
 320     for(UChar32 c = 0xc0; c <= 0xff; ++c) {
 321         utrie2_set32(trie, c, Collation::FALLBACK_CE32, &errorCode);
 322     }
 323
 324     // Hangul syllables are not tailorable (except via tailoring Jamos).
 325     // Always set the Hangul tag to help performance.
 326     // Do this here, rather than in buildMappings(),
 327     // so that we see the HANGUL_TAG in various assertions.
 328     uint32_t hangulCE32 = Collation::makeCE32FromTagAndIndex(Collation::HANGUL_TAG, 0);
 329     utrie2_setRange32(trie, Hangul::HANGUL_BASE, Hangul::HANGUL_END, hangulCE32, TRUE, &errorCode);
 330
 331     // Copy the set contents but don't copy/clone the set as a whole because
 332     // that would copy the isFrozen state too.
 333     unsafeBackwardSet.addAll(*b->unsafeBackwardSet);
 334
 335     if(U_FAILURE(errorCode)) { return; }
 336 }
 337
 338 UBool
 339 CollationDataBuilder::maybeSetPrimaryRange(UChar32 start, UChar32 end,
 340                                            uint32_t primary, int32_t step,
 341                                            UErrorCode &errorCode) {
 342     if(U_FAILURE(errorCode)) { return FALSE; }
 343     U_ASSERT(start <= end);
 344     // TODO: Do we need to check what values are currently set for start..end?
 345     // An offset range is worth it only if we can achieve an overlap between
 346     // adjacent UTrie2 blocks of 32 code points each.
 347     // An offset CE is also a little more expensive to look up and compute
 348     // than a simple CE.
 349     // If the range spans at least three UTrie2 block boundaries (> 64 code points),
 350     // then we take it.
 351     // If the range spans one or two block boundaries and there are
 352     // at least 4 code points on either side, then we take it.
 353     // (We could additionally require a minimum range length of, say, 16.)
 354     int32_t blockDelta = (end >> 5) - (start >> 5);
 355     if(2 <= step && step <= 0x7f &&
 356             (blockDelta >= 3 ||
 357             (blockDelta > 0 && (start & 0x1f) <= 0x1c && (end & 0x1f) >= 3))) {
 358         int64_t dataCE = ((int64_t)primary << 32) | (start << 8) | step;
 359         if(isCompressiblePrimary(primary)) { dataCE |= 0x80; }
 360         int32_t index = addCE(dataCE, errorCode);
 361         if(U_FAILURE(errorCode)) { return 0; }
 362         if(index > Collation::MAX_INDEX) {
 363             errorCode = U_BUFFER_OVERFLOW_ERROR;
 364             return 0;
 365         }
 366         uint32_t offsetCE32 = Collation::makeCE32FromTagAndIndex(Collation::OFFSET_TAG, index);
 367         utrie2_setRange32(trie, start, end, offsetCE32, TRUE, &errorCode);
 368         modified = TRUE;
 369         return TRUE;
 370     } else {
 371         return FALSE;
 372     }
 373 }
 374
 375 uint32_t
 376 CollationDataBuilder::setPrimaryRangeAndReturnNext(UChar32 start, UChar32 end,
 377                                                    uint32_t primary, int32_t step,
 378                                                    UErrorCode &errorCode) {
 379     if(U_FAILURE(errorCode)) { return 0; }
 380     UBool isCompressible = isCompressiblePrimary(primary);
 381     if(maybeSetPrimaryRange(start, end, primary, step, errorCode)) {
 382         return Collation::incThreeBytePrimaryByOffset(primary, isCompressible,
 383                                                       (end - start + 1) * step);
 384     } else {
 385         // Short range: Set individual CE32s.
 386         for(;;) {
 387             utrie2_set32(trie, start, Collation::makeLongPrimaryCE32(primary), &errorCode);
 388             ++start;
 389             primary = Collation::incThreeBytePrimaryByOffset(primary, isCompressible, step);
 390             if(start > end) { return primary; }
 391         }
 392         modified = TRUE;
 393     }
 394 }
 395
 396 uint32_t
 397 CollationDataBuilder::getCE32FromOffsetCE32(UBool fromBase, UChar32 c, uint32_t ce32) const {
 398     int32_t i = Collation::indexFromCE32(ce32);
 399     int64_t dataCE = fromBase ? base->ces[i] : ce64s.elementAti(i);
 400     uint32_t p = Collation::getThreeBytePrimaryForOffsetData(c, dataCE);
 401     return Collation::makeLongPrimaryCE32(p);
 402 }
 403
 404 UBool
 405 CollationDataBuilder::isCompressibleLeadByte(uint32_t b) const {
 406     return base->isCompressibleLeadByte(b);
 407 }
 408
 409 UBool
 410 CollationDataBuilder::isAssigned(UChar32 c) const {
 411     return Collation::isAssignedCE32(utrie2_get32(trie, c));
 412 }
 413
 414 uint32_t
 415 CollationDataBuilder::getLongPrimaryIfSingleCE(UChar32 c) const {
 416     uint32_t ce32 = utrie2_get32(trie, c);
 417     if(Collation::isLongPrimaryCE32(ce32)) {
 418         return Collation::primaryFromLongPrimaryCE32(ce32);
 419     } else {
 420         return 0;
 421     }
 422 }
 423
 424 int64_t
 425 CollationDataBuilder::getSingleCE(UChar32 c, UErrorCode &errorCode) const {
 426     if(U_FAILURE(errorCode)) { return 0; }
 427     // Keep parallel with CollationData::getSingleCE().
 428     UBool fromBase = FALSE;
 429     uint32_t ce32 = utrie2_get32(trie, c);
 430     if(ce32 == Collation::FALLBACK_CE32) {
 431         fromBase = TRUE;
 432         ce32 = base->getCE32(c);
 433     }
 434     while(Collation::isSpecialCE32(ce32)) {
 435         switch(Collation::tagFromCE32(ce32)) {
 436         case Collation::LATIN_EXPANSION_TAG:
 437         case Collation::BUILDER_DATA_TAG:
 438         case Collation::PREFIX_TAG:
 439         case Collation::CONTRACTION_TAG:
 440         case Collation::HANGUL_TAG:
 441         case Collation::LEAD_SURROGATE_TAG:
 442             errorCode = U_UNSUPPORTED_ERROR;
 443             return 0;
 444         case Collation::FALLBACK_TAG:
 445         case Collation::RESERVED_TAG_3:
 446             errorCode = U_INTERNAL_PROGRAM_ERROR;
 447             return 0;
 448         case Collation::LONG_PRIMARY_TAG:
 449             return Collation::ceFromLongPrimaryCE32(ce32);
 450         case Collation::LONG_SECONDARY_TAG:
 451             return Collation::ceFromLongSecondaryCE32(ce32);
 452         case Collation::EXPANSION32_TAG:
 453             if(Collation::lengthFromCE32(ce32) == 1) {
 454                 int32_t i = Collation::indexFromCE32(ce32);
 455                 ce32 = fromBase ? base->ce32s[i] : ce32s.elementAti(i);
 456                 break;
 457             } else {
 458                 errorCode = U_UNSUPPORTED_ERROR;
 459                 return 0;
 460             }
 461         case Collation::EXPANSION_TAG: {
 462             if(Collation::lengthFromCE32(ce32) == 1) {
 463                 int32_t i = Collation::indexFromCE32(ce32);
 464                 return fromBase ? base->ces[i] : ce64s.elementAti(i);
 465             } else {
 466                 errorCode = U_UNSUPPORTED_ERROR;
 467                 return 0;
 468             }
 469         }
 470         case Collation::DIGIT_TAG:
 471             // Fetch the non-numeric-collation CE32 and continue.
 472             ce32 = ce32s.elementAti(Collation::indexFromCE32(ce32));
 473             break;
 474         case Collation::U0000_TAG:
 475             U_ASSERT(c == 0);
 476             // Fetch the normal ce32 for U+0000 and continue.
 477             ce32 = fromBase ? base->ce32s[0] : ce32s.elementAti(0);
 478             break;
 479         case Collation::OFFSET_TAG:
 480             ce32 = getCE32FromOffsetCE32(fromBase, c, ce32);
 481             break;
 482         case Collation::IMPLICIT_TAG:
 483             return Collation::unassignedCEFromCodePoint(c);
 484         }
 485     }
 486     return Collation::ceFromSimpleCE32(ce32);
 487 }
 488
 489 int32_t
 490 CollationDataBuilder::addCE(int64_t ce, UErrorCode &errorCode) {
 491     int32_t length = ce64s.size();
 492     for(int32_t i = 0; i < length; ++i) {
 493         if(ce == ce64s.elementAti(i)) { return i; }
 494     }
 495     ce64s.addElement(ce, errorCode);
 496     return length;
 497 }
 498
 499 int32_t
 500 CollationDataBuilder::addCE32(uint32_t ce32, UErrorCode &errorCode) {
 501     int32_t length = ce32s.size();
 502     for(int32_t i = 0; i < length; ++i) {
 503         if(ce32 == (uint32_t)ce32s.elementAti(i)) { return i; }
 504     }
 505     ce32s.addElement((int32_t)ce32, errorCode);
 506     return length;
 507 }
 508
 509 int32_t
 510 CollationDataBuilder::addConditionalCE32(const UnicodeString &context, uint32_t ce32,
 511                                          UErrorCode &errorCode) {
 512     if(U_FAILURE(errorCode)) { return -1; }
 513     U_ASSERT(!context.isEmpty());
 514     int32_t index = conditionalCE32s.size();
 515     if(index > Collation::MAX_INDEX) {
 516         errorCode = U_BUFFER_OVERFLOW_ERROR;
 517         return -1;
 518     }
 519     ConditionalCE32 *cond = new ConditionalCE32(context, ce32);
 520     if(cond == NULL) {
 521         errorCode = U_MEMORY_ALLOCATION_ERROR;
 522         return -1;
 523     }
 524     conditionalCE32s.addElement(cond, errorCode);
 525     return index;
 526 }
 527
 528 void
 529 CollationDataBuilder::add(const UnicodeString &prefix, const UnicodeString &s,
 530                           const int64_t ces[], int32_t cesLength,
 531                           UErrorCode &errorCode) {
 532     uint32_t ce32 = encodeCEs(ces, cesLength, errorCode);
 533     addCE32(prefix, s, ce32, errorCode);
 534 }
 535
 536 void
 537 CollationDataBuilder::addCE32(const UnicodeString &prefix, const UnicodeString &s,
 538                               uint32_t ce32, UErrorCode &errorCode) {
 539     if(U_FAILURE(errorCode)) { return; }
 540     if(s.isEmpty()) {
 541         errorCode = U_ILLEGAL_ARGUMENT_ERROR;
 542         return;
 543     }
 544     if(trie == NULL || utrie2_isFrozen(trie)) {
 545         errorCode = U_INVALID_STATE_ERROR;
 546         return;
 547     }
 548     UChar32 c = s.char32At(0);
 549     int32_t cLength = U16_LENGTH(c);
 550     uint32_t oldCE32 = utrie2_get32(trie, c);
 551     UBool hasContext = !prefix.isEmpty() || s.length() > cLength;
 552     if(oldCE32 == Collation::FALLBACK_CE32) {
 553         // First tailoring for c.
 554         // If c has contextual base mappings or if we add a contextual mapping,
 555         // then copy the base mappings.
 556         // Otherwise we just override the base mapping.
 557         uint32_t baseCE32 = base->getFinalCE32(base->getCE32(c));
 558         if(hasContext || Collation::ce32HasContext(baseCE32)) {
 559             oldCE32 = copyFromBaseCE32(c, baseCE32, TRUE, errorCode);
 560             utrie2_set32(trie, c, oldCE32, &errorCode);
 561             if(U_FAILURE(errorCode)) { return; }
 562         }
 563     }
 564     if(!hasContext) {
 565         // No prefix, no contraction.
 566         if(!isBuilderContextCE32(oldCE32)) {
 567             utrie2_set32(trie, c, ce32, &errorCode);
 568         } else {
 569             ConditionalCE32 *cond = getConditionalCE32ForCE32(oldCE32);
 570             cond->builtCE32 = Collation::NO_CE32;
 571             cond->ce32 = ce32;
 572         }
 573     } else {
 574         ConditionalCE32 *cond;
 575         if(!isBuilderContextCE32(oldCE32)) {
 576             // Replace the simple oldCE32 with a builder context CE32
 577             // pointing to a new ConditionalCE32 list head.
 578             int32_t index = addConditionalCE32(UnicodeString((UChar)0), oldCE32, errorCode);
 579             if(U_FAILURE(errorCode)) { return; }
 580             uint32_t contextCE32 = makeBuilderContextCE32(index);
 581             utrie2_set32(trie, c, contextCE32, &errorCode);
 582             contextChars.add(c);
 583             cond = getConditionalCE32(index);
 584         } else {
 585             cond = getConditionalCE32ForCE32(oldCE32);
 586             cond->builtCE32 = Collation::NO_CE32;
 587         }
 588         UnicodeString suffix(s, cLength);
 589         UnicodeString context((UChar)prefix.length());
 590         context.append(prefix).append(suffix);
 591         unsafeBackwardSet.addAll(suffix);
 592         for(;;) {
 593             // invariant: context > cond->context
 594             int32_t next = cond->next;
 595             if(next < 0) {
 596                 // Append a new ConditionalCE32 after cond.
 597                 int32_t index = addConditionalCE32(context, ce32, errorCode);
 598                 if(U_FAILURE(errorCode)) { return; }
 599                 cond->next = index;
 600                 break;
 601             }
 602             ConditionalCE32 *nextCond = getConditionalCE32(next);
 603             int8_t cmp = context.compare(nextCond->context);
 604             if(cmp < 0) {
 605                 // Insert a new ConditionalCE32 between cond and nextCond.
 606                 int32_t index = addConditionalCE32(context, ce32, errorCode);
 607                 if(U_FAILURE(errorCode)) { return; }
 608                 cond->next = index;
 609                 getConditionalCE32(index)->next = next;
 610                 break;
 611             } else if(cmp == 0) {
 612                 // Same context as before, overwrite its ce32.
 613                 nextCond->ce32 = ce32;
 614                 break;
 615             }
 616             cond = nextCond;
 617         }
 618     }
 619     modified = TRUE;
 620 }
 621
 622 uint32_t
 623 CollationDataBuilder::encodeOneCEAsCE32(int64_t ce) {
 624     uint32_t p = (uint32_t)(ce >> 32);
 625     uint32_t lower32 = (uint32_t)ce;
 626     uint32_t t = (uint32_t)(ce & 0xffff);
 627     U_ASSERT((t & 0xc000) != 0xc000);  // Impossible case bits 11 mark special CE32s.
 628     if((ce & INT64_C(0xffff00ff00ff)) == 0) {
 629         // normal form ppppsstt
 630         return p | (lower32 >> 16) | (t >> 8);
 631     } else if((ce & INT64_C(0xffffffffff)) == Collation::COMMON_SEC_AND_TER_CE) {
 632         // long-primary form ppppppC1
 633         return Collation::makeLongPrimaryCE32(p);
 634     } else if(p == 0 && (t & 0xff) == 0) {
 635         // long-secondary form ssssttC2
 636         return Collation::makeLongSecondaryCE32(lower32);
 637     }
 638     return Collation::NO_CE32;
 639 }
 640
 641 uint32_t
 642 CollationDataBuilder::encodeOneCE(int64_t ce, UErrorCode &errorCode) {
 643     // Try to encode one CE as one CE32.
 644     uint32_t ce32 = encodeOneCEAsCE32(ce);
 645     if(ce32 != Collation::NO_CE32) { return ce32; }
 646     int32_t index = addCE(ce, errorCode);
 647     if(U_FAILURE(errorCode)) { return 0; }
 648     if(index > Collation::MAX_INDEX) {
 649         errorCode = U_BUFFER_OVERFLOW_ERROR;
 650         return 0;
 651     }
 652     return Collation::makeCE32FromTagIndexAndLength(Collation::EXPANSION_TAG, index, 1);
 653 }
 654
 655 uint32_t
 656 CollationDataBuilder::encodeCEs(const int64_t ces[], int32_t cesLength,
 657                                 UErrorCode &errorCode) {
 658     if(U_FAILURE(errorCode)) { return 0; }
 659     if(cesLength < 0 || cesLength > Collation::MAX_EXPANSION_LENGTH) {
 660         errorCode = U_ILLEGAL_ARGUMENT_ERROR;
 661         return 0;
 662     }
 663     if(trie == NULL || utrie2_isFrozen(trie)) {
 664         errorCode = U_INVALID_STATE_ERROR;
 665         return 0;
 666     }
 667     if(cesLength == 0) {
 668         // Convenience: We cannot map to nothing, but we can map to a completely ignorable CE.
 669         // Do this here so that callers need not do it.
 670         return encodeOneCEAsCE32(0);
 671     } else if(cesLength == 1) {
 672         return encodeOneCE(ces[0], errorCode);
 673     } else if(cesLength == 2) {
 674         // Try to encode two CEs as one CE32.
 675         int64_t ce0 = ces[0];
 676         int64_t ce1 = ces[1];
 677         uint32_t p0 = (uint32_t)(ce0 >> 32);
 678         if((ce0 & INT64_C(0xffffffffff00ff)) == Collation::COMMON_SECONDARY_CE &&
 679                 (ce1 & INT64_C(0xffffffff00ffffff)) == Collation::COMMON_TERTIARY_CE &&
 680                 p0 != 0) {
 681             // Latin mini expansion
 682             return
 683                 p0 |
 684                 (((uint32_t)ce0 & 0xff00u) << 8) |
 685                 (uint32_t)(ce1 >> 16) |
 686                 Collation::SPECIAL_CE32_LOW_BYTE |
 687                 Collation::LATIN_EXPANSION_TAG;
 688         }
 689     }
 690     // Try to encode two or more CEs as CE32s.
 691     int32_t newCE32s[Collation::MAX_EXPANSION_LENGTH];
 692     for(int32_t i = 0;; ++i) {
 693         if(i == cesLength) {
 694             return encodeExpansion32(newCE32s, cesLength, errorCode);
 695         }
 696         uint32_t ce32 = encodeOneCEAsCE32(ces[i]);
 697         if(ce32 == Collation::NO_CE32) { break; }
 698         newCE32s[i] = (int32_t)ce32;
 699     }
 700     return encodeExpansion(ces, cesLength, errorCode);
 701 }
 702
 703 uint32_t
 704 CollationDataBuilder::encodeExpansion(const int64_t ces[], int32_t length, UErrorCode &errorCode) {
 705     if(U_FAILURE(errorCode)) { return 0; }
 706     // See if this sequence of CEs has already been stored.
 707     int64_t first = ces[0];
 708     int32_t ce64sMax = ce64s.size() - length;
 709     for(int32_t i = 0; i <= ce64sMax; ++i) {
 710         if(first == ce64s.elementAti(i)) {
 711             if(i > Collation::MAX_INDEX) {
 712                 errorCode = U_BUFFER_OVERFLOW_ERROR;
 713                 return 0;
 714             }
 715             for(int32_t j = 1;; ++j) {
 716                 if(j == length) {
 717                     return Collation::makeCE32FromTagIndexAndLength(
 718                             Collation::EXPANSION_TAG, i, length);
 719                 }
 720                 if(ce64s.elementAti(i + j) != ces[j]) { break; }
 721             }
 722         }
 723     }
 724     // Store the new sequence.
 725     int32_t i = ce64s.size();
 726     if(i > Collation::MAX_INDEX) {
 727         errorCode = U_BUFFER_OVERFLOW_ERROR;
 728         return 0;
 729     }
 730     for(int32_t j = 0; j < length; ++j) {
 731         ce64s.addElement(ces[j], errorCode);
 732     }
 733     return Collation::makeCE32FromTagIndexAndLength(Collation::EXPANSION_TAG, i, length);
 734 }
 735
 736 uint32_t
 737 CollationDataBuilder::encodeExpansion32(const int32_t newCE32s[], int32_t length,
 738                                         UErrorCode &errorCode) {
 739     if(U_FAILURE(errorCode)) { return 0; }
 740     // See if this sequence of CE32s has already been stored.
 741     int32_t first = newCE32s[0];
 742     int32_t ce32sMax = ce32s.size() - length;
 743     for(int32_t i = 0; i <= ce32sMax; ++i) {
 744         if(first == ce32s.elementAti(i)) {
 745             if(i > Collation::MAX_INDEX) {
 746                 errorCode = U_BUFFER_OVERFLOW_ERROR;
 747                 return 0;
 748             }
 749             for(int32_t j = 1;; ++j) {
 750                 if(j == length) {
 751                     return Collation::makeCE32FromTagIndexAndLength(
 752                             Collation::EXPANSION32_TAG, i, length);
 753                 }
 754                 if(ce32s.elementAti(i + j) != newCE32s[j]) { break; }
 755             }
 756         }
 757     }
 758     // Store the new sequence.
 759     int32_t i = ce32s.size();
 760     if(i > Collation::MAX_INDEX) {
 761         errorCode = U_BUFFER_OVERFLOW_ERROR;
 762         return 0;
 763     }
 764     for(int32_t j = 0; j < length; ++j) {
 765         ce32s.addElement(newCE32s[j], errorCode);
 766     }
 767     return Collation::makeCE32FromTagIndexAndLength(Collation::EXPANSION32_TAG, i, length);
 768 }
 769
 770 uint32_t
 771 CollationDataBuilder::copyFromBaseCE32(UChar32 c, uint32_t ce32, UBool withContext,
 772                                        UErrorCode &errorCode) {
 773     if(U_FAILURE(errorCode)) { return 0; }
 774     if(!Collation::isSpecialCE32(ce32)) { return ce32; }
 775     switch(Collation::tagFromCE32(ce32)) {
 776     case Collation::LONG_PRIMARY_TAG:
 777     case Collation::LONG_SECONDARY_TAG:
 778     case Collation::LATIN_EXPANSION_TAG:
 779         // copy as is
 780         break;
 781     case Collation::EXPANSION32_TAG: {
 782         const uint32_t *baseCE32s = base->ce32s + Collation::indexFromCE32(ce32);
 783         int32_t length = Collation::lengthFromCE32(ce32);
 784         ce32 = encodeExpansion32(
 785             reinterpret_cast<const int32_t *>(baseCE32s), length, errorCode);
 786         break;
 787     }
 788     case Collation::EXPANSION_TAG: {
 789         const int64_t *baseCEs = base->ces + Collation::indexFromCE32(ce32);
 790         int32_t length = Collation::lengthFromCE32(ce32);
 791         ce32 = encodeExpansion(baseCEs, length, errorCode);
 792         break;
 793     }
 794     case Collation::PREFIX_TAG: {
 795         // Flatten prefixes and nested suffixes (contractions)
 796         // into a linear list of ConditionalCE32.
 797         const UChar *p = base->contexts + Collation::indexFromCE32(ce32);
 798         ce32 = CollationData::readCE32(p);  // Default if no prefix match.
 799         if(!withContext) {
 800             return copyFromBaseCE32(c, ce32, FALSE, errorCode);
 801         }
 802         ConditionalCE32 head;
 803         UnicodeString context((UChar)0);
 804         int32_t index;
 805         if(Collation::isContractionCE32(ce32)) {
 806             index = copyContractionsFromBaseCE32(context, c, ce32, &head, errorCode);
 807         } else {
 808             ce32 = copyFromBaseCE32(c, ce32, TRUE, errorCode);
 809             head.next = index = addConditionalCE32(context, ce32, errorCode);
 810         }
 811         if(U_FAILURE(errorCode)) { return 0; }
 812         ConditionalCE32 *cond = getConditionalCE32(index);  // the last ConditionalCE32 so far
 813         UCharsTrie::Iterator prefixes(p + 2, 0, errorCode);
 814         while(prefixes.next(errorCode)) {
 815             context = prefixes.getString();
 816             context.reverse();
 817             context.insert(0, (UChar)context.length());
 818             ce32 = (uint32_t)prefixes.getValue();
 819             if(Collation::isContractionCE32(ce32)) {
 820                 index = copyContractionsFromBaseCE32(context, c, ce32, cond, errorCode);
 821             } else {
 822                 ce32 = copyFromBaseCE32(c, ce32, TRUE, errorCode);
 823                 cond->next = index = addConditionalCE32(context, ce32, errorCode);
 824             }
 825             if(U_FAILURE(errorCode)) { return 0; }
 826             cond = getConditionalCE32(index);
 827         }
 828         ce32 = makeBuilderContextCE32(head.next);
 829         contextChars.add(c);
 830         break;
 831     }
 832     case Collation::CONTRACTION_TAG: {
 833         if(!withContext) {
 834             const UChar *p = base->contexts + Collation::indexFromCE32(ce32);
 835             ce32 = CollationData::readCE32(p);  // Default if no suffix match.
 836             return copyFromBaseCE32(c, ce32, FALSE, errorCode);
 837         }
 838         ConditionalCE32 head;
 839         UnicodeString context((UChar)0);
 840         copyContractionsFromBaseCE32(context, c, ce32, &head, errorCode);
 841         ce32 = makeBuilderContextCE32(head.next);
 842         contextChars.add(c);
 843         break;
 844     }
 845     case Collation::HANGUL_TAG:
 846         errorCode = U_UNSUPPORTED_ERROR;  // We forbid tailoring of Hangul syllables.
 847         break;
 848     case Collation::OFFSET_TAG:
 849         ce32 = getCE32FromOffsetCE32(TRUE, c, ce32);
 850         break;
 851     case Collation::IMPLICIT_TAG:
 852         ce32 = encodeOneCE(Collation::unassignedCEFromCodePoint(c), errorCode);
 853         break;
 854     default:
 855         U_ASSERT(FALSE);  // require ce32 == base->getFinalCE32(ce32)
 856         break;
 857     }
 858     return ce32;
 859 }
 860
 861 int32_t
 862 CollationDataBuilder::copyContractionsFromBaseCE32(UnicodeString &context, UChar32 c, uint32_t ce32,
 863                                                    ConditionalCE32 *cond, UErrorCode &errorCode) {
 864     if(U_FAILURE(errorCode)) { return 0; }
 865     const UChar *p = base->contexts + Collation::indexFromCE32(ce32);
 866     int32_t index;
 867     if((ce32 & Collation::CONTRACT_SINGLE_CP_NO_MATCH) != 0) {
 868         // No match on the single code point.
 869         // We are underneath a prefix, and the default mapping is just
 870         // a fallback to the mappings for a shorter prefix.
 871         U_ASSERT(context.length() > 1);
 872         index = -1;
 873     } else {
 874         ce32 = CollationData::readCE32(p);  // Default if no suffix match.
 875         U_ASSERT(!Collation::isContractionCE32(ce32));
 876         ce32 = copyFromBaseCE32(c, ce32, TRUE, errorCode);
 877         cond->next = index = addConditionalCE32(context, ce32, errorCode);
 878         if(U_FAILURE(errorCode)) { return 0; }
 879         cond = getConditionalCE32(index);
 880     }
 881
 882     int32_t suffixStart = context.length();
 883     UCharsTrie::Iterator suffixes(p + 2, 0, errorCode);
 884     while(suffixes.next(errorCode)) {
 885         context.append(suffixes.getString());
 886         ce32 = copyFromBaseCE32(c, (uint32_t)suffixes.getValue(), TRUE, errorCode);
 887         cond->next = index = addConditionalCE32(context, ce32, errorCode);
 888         if(U_FAILURE(errorCode)) { return 0; }
 889         // No need to update the unsafeBackwardSet because the tailoring set
 890         // is already a copy of the base set.
 891         cond = getConditionalCE32(index);
 892         context.truncate(suffixStart);
 893     }
 894     U_ASSERT(index >= 0);
 895     return index;
 896 }
 897
 898 class CopyHelper {
 899 public:
 900     CopyHelper(const CollationDataBuilder &s, CollationDataBuilder &d,
 901                const CollationDataBuilder::CEModifier &m, UErrorCode &initialErrorCode)
 902             : src(s), dest(d), modifier(m),
 903               errorCode(initialErrorCode) {}
 904
 905     UBool copyRangeCE32(UChar32 start, UChar32 end, uint32_t ce32) {
 906         ce32 = copyCE32(ce32);
 907         utrie2_setRange32(dest.trie, start, end, ce32, TRUE, &errorCode);
 908         if(CollationDataBuilder::isBuilderContextCE32(ce32)) {
 909             dest.contextChars.add(start, end);
 910         }
 911         return U_SUCCESS(errorCode);
 912     }
 913
 914     uint32_t copyCE32(uint32_t ce32) {
 915         if(!Collation::isSpecialCE32(ce32)) {
 916             int64_t ce = modifier.modifyCE32(ce32);
 917             if(ce != Collation::NO_CE) {
 918                 ce32 = dest.encodeOneCE(ce, errorCode);
 919             }
 920         } else {
 921             int32_t tag = Collation::tagFromCE32(ce32);
 922             if(tag == Collation::EXPANSION32_TAG) {
 923                 const uint32_t *srcCE32s = reinterpret_cast<uint32_t *>(src.ce32s.getBuffer());
 924                 srcCE32s += Collation::indexFromCE32(ce32);
 925                 int32_t length = Collation::lengthFromCE32(ce32);
 926                 // Inspect the source CE32s. Just copy them if none are modified.
 927                 // Otherwise copy to modifiedCEs, with modifications.
 928                 UBool isModified = FALSE;
 929                 for(int32_t i = 0; i < length; ++i) {
 930                     ce32 = srcCE32s[i];
 931                     int64_t ce;
 932                     if(Collation::isSpecialCE32(ce32) ||
 933                             (ce = modifier.modifyCE32(ce32)) == Collation::NO_CE) {
 934                         if(isModified) {
 935                             modifiedCEs[i] = Collation::ceFromCE32(ce32);
 936                         }
 937                     } else {
 938                         if(!isModified) {
 939                             for(int32_t j = 0; j < i; ++j) {
 940                                 modifiedCEs[j] = Collation::ceFromCE32(srcCE32s[j]);
 941                             }
 942                             isModified = TRUE;
 943                         }
 944                         modifiedCEs[i] = ce;
 945                     }
 946                 }
 947                 if(isModified) {
 948                     ce32 = dest.encodeCEs(modifiedCEs, length, errorCode);
 949                 } else {
 950                     ce32 = dest.encodeExpansion32(
 951                         reinterpret_cast<const int32_t *>(srcCE32s), length, errorCode);
 952                 }
 953             } else if(tag == Collation::EXPANSION_TAG) {
 954                 const int64_t *srcCEs = src.ce64s.getBuffer();
 955                 srcCEs += Collation::indexFromCE32(ce32);
 956                 int32_t length = Collation::lengthFromCE32(ce32);
 957                 // Inspect the source CEs. Just copy them if none are modified.
 958                 // Otherwise copy to modifiedCEs, with modifications.
 959                 UBool isModified = FALSE;
 960                 for(int32_t i = 0; i < length; ++i) {
 961                     int64_t srcCE = srcCEs[i];
 962                     int64_t ce = modifier.modifyCE(srcCE);
 963                     if(ce == Collation::NO_CE) {
 964                         if(isModified) {
 965                             modifiedCEs[i] = srcCE;
 966                         }
 967                     } else {
 968                         if(!isModified) {
 969                             for(int32_t j = 0; j < i; ++j) {
 970                                 modifiedCEs[j] = srcCEs[j];
 971                             }
 972                             isModified = TRUE;
 973                         }
 974                         modifiedCEs[i] = ce;
 975                     }
 976                 }
 977                 if(isModified) {
 978                     ce32 = dest.encodeCEs(modifiedCEs, length, errorCode);
 979                 } else {
 980                     ce32 = dest.encodeExpansion(srcCEs, length, errorCode);
 981                 }
 982             } else if(tag == Collation::BUILDER_DATA_TAG) {
 983                 // Copy the list of ConditionalCE32.
 984                 ConditionalCE32 *cond = src.getConditionalCE32ForCE32(ce32);
 985                 U_ASSERT(!cond->hasContext());
 986                 int32_t destIndex = dest.addConditionalCE32(
 987                         cond->context, copyCE32(cond->ce32), errorCode);
 988                 ce32 = CollationDataBuilder::makeBuilderContextCE32(destIndex);
 989                 while(cond->next >= 0) {
 990                     cond = src.getConditionalCE32(cond->next);
 991                     ConditionalCE32 *prevDestCond = dest.getConditionalCE32(destIndex);
 992                     destIndex = dest.addConditionalCE32(
 993                             cond->context, copyCE32(cond->ce32), errorCode);
 994                     int32_t suffixStart = cond->prefixLength() + 1;
 995                     dest.unsafeBackwardSet.addAll(cond->context.tempSubString(suffixStart));
 996                     prevDestCond->next = destIndex;
 997                 }
 998             } else {
 999                 // Just copy long CEs and Latin mini expansions (and other expected values) as is,
1000                 // assuming that the modifier would not modify them.
1001                 U_ASSERT(tag == Collation::LONG_PRIMARY_TAG ||
1002                         tag == Collation::LONG_SECONDARY_TAG ||
1003                         tag == Collation::LATIN_EXPANSION_TAG ||
1004                         tag == Collation::HANGUL_TAG);
1005             }
1006         }
1007         return ce32;
1008     }
1009
1010     const CollationDataBuilder &src;
1011     CollationDataBuilder &dest;
1012     const CollationDataBuilder::CEModifier &modifier;
1013     int64_t modifiedCEs[Collation::MAX_EXPANSION_LENGTH];
1014     UErrorCode errorCode;
1015 };
1016
1017 U_CDECL_BEGIN
1018
1019 static UBool U_CALLCONV
1020 enumRangeForCopy(const void *context, UChar32 start, UChar32 end, uint32_t value) {
1021     return
1022         value == Collation::UNASSIGNED_CE32 || value == Collation::FALLBACK_CE32 ||
1023         ((CopyHelper *)context)->copyRangeCE32(start, end, value);
1024 }
1025
1026 U_CDECL_END
1027
1028 void
1029 CollationDataBuilder::copyFrom(const CollationDataBuilder &src, const CEModifier &modifier,
1030                                UErrorCode &errorCode) {
1031     if(U_FAILURE(errorCode)) { return; }
1032     if(trie == NULL || utrie2_isFrozen(trie)) {
1033         errorCode = U_INVALID_STATE_ERROR;
1034         return;
1035     }
1036     CopyHelper helper(src, *this, modifier, errorCode);
1037     utrie2_enum(src.trie, NULL, enumRangeForCopy, &helper);
1038     errorCode = helper.errorCode;
1039     // Update the contextChars and the unsafeBackwardSet while copying,
1040     // in case a character had conditional mappings in the source builder
1041     // and they were removed later.
1042     modified |= src.modified;
1043 }
1044
1045 void
1046 CollationDataBuilder::optimize(const UnicodeSet &set, UErrorCode &errorCode) {
1047     if(U_FAILURE(errorCode) || set.isEmpty()) { return; }
1048     UnicodeSetIterator iter(set);
1049     while(iter.next() && !iter.isString()) {
1050         UChar32 c = iter.getCodepoint();
1051         uint32_t ce32 = utrie2_get32(trie, c);
1052         if(ce32 == Collation::FALLBACK_CE32) {
1053             ce32 = base->getFinalCE32(base->getCE32(c));
1054             ce32 = copyFromBaseCE32(c, ce32, TRUE, errorCode);
1055             utrie2_set32(trie, c, ce32, &errorCode);
1056         }
1057     }
1058     modified = TRUE;
1059 }
1060
1061 void
1062 CollationDataBuilder::suppressContractions(const UnicodeSet &set, UErrorCode &errorCode) {
1063     if(U_FAILURE(errorCode) || set.isEmpty()) { return; }
1064     UnicodeSetIterator iter(set);
1065     while(iter.next() && !iter.isString()) {
1066         UChar32 c = iter.getCodepoint();
1067         uint32_t ce32 = utrie2_get32(trie, c);
1068         if(ce32 == Collation::FALLBACK_CE32) {
1069             ce32 = base->getFinalCE32(base->getCE32(c));
1070             if(Collation::ce32HasContext(ce32)) {
1071                 ce32 = copyFromBaseCE32(c, ce32, FALSE /* without context */, errorCode);
1072                 utrie2_set32(trie, c, ce32, &errorCode);
1073             }
1074         } else if(isBuilderContextCE32(ce32)) {
1075             ce32 = getConditionalCE32ForCE32(ce32)->ce32;
1076             // Simply abandon the list of ConditionalCE32.
1077             // The caller will copy this builder in the end,
1078             // eliminating unreachable data.
1079             utrie2_set32(trie, c, ce32, &errorCode);
1080             contextChars.remove(c);
1081         }
1082     }
1083     modified = TRUE;
1084 }
1085
1086 UBool
1087 CollationDataBuilder::getJamoCE32s(uint32_t jamoCE32s[], UErrorCode &errorCode) {
1088     if(U_FAILURE(errorCode)) { return FALSE; }
1089     UBool anyJamoAssigned = base == NULL;  // always set jamoCE32s in the base data
1090     UBool needToCopyFromBase = FALSE;
1091     for(int32_t j = 0; j < CollationData::JAMO_CE32S_LENGTH; ++j) {  // Count across Jamo types.
1092         UChar32 jamo = jamoCpFromIndex(j);
1093         UBool fromBase = FALSE;
1094         uint32_t ce32 = utrie2_get32(trie, jamo);
1095         anyJamoAssigned |= Collation::isAssignedCE32(ce32);
1096         // TODO: Try to prevent [optimize [Jamo]] from counting as anyJamoAssigned.
1097         // (As of CLDR 24 [2013] the Korean tailoring does not optimize conjoining Jamo.)
1098         if(ce32 == Collation::FALLBACK_CE32) {
1099             fromBase = TRUE;
1100             ce32 = base->getCE32(jamo);
1101         }
1102         if(Collation::isSpecialCE32(ce32)) {
1103             switch(Collation::tagFromCE32(ce32)) {
1104             case Collation::LONG_PRIMARY_TAG:
1105             case Collation::LONG_SECONDARY_TAG:
1106             case Collation::LATIN_EXPANSION_TAG:
1107                 // Copy the ce32 as-is.
1108                 break;
1109             case Collation::EXPANSION32_TAG:
1110             case Collation::EXPANSION_TAG:
1111             case Collation::PREFIX_TAG:
1112             case Collation::CONTRACTION_TAG:
1113                 if(fromBase) {
1114                     // Defer copying until we know if anyJamoAssigned.
1115                     ce32 = Collation::FALLBACK_CE32;
1116                     needToCopyFromBase = TRUE;
1117                 }
1118                 break;
1119             case Collation::IMPLICIT_TAG:
1120                 // An unassigned Jamo should only occur in tests with incomplete bases.
1121                 U_ASSERT(fromBase);
1122                 ce32 = Collation::FALLBACK_CE32;
1123                 needToCopyFromBase = TRUE;
1124                 break;
1125             case Collation::OFFSET_TAG:
1126                 ce32 = getCE32FromOffsetCE32(fromBase, jamo, ce32);
1127                 break;
1128             case Collation::FALLBACK_TAG:
1129             case Collation::RESERVED_TAG_3:
1130             case Collation::BUILDER_DATA_TAG:
1131             case Collation::DIGIT_TAG:
1132             case Collation::U0000_TAG:
1133             case Collation::HANGUL_TAG:
1134             case Collation::LEAD_SURROGATE_TAG:
1135                 errorCode = U_INTERNAL_PROGRAM_ERROR;
1136                 return FALSE;
1137             }
1138         }
1139         jamoCE32s[j] = ce32;
1140     }
1141     if(anyJamoAssigned && needToCopyFromBase) {
1142         for(int32_t j = 0; j < CollationData::JAMO_CE32S_LENGTH; ++j) {
1143             if(jamoCE32s[j] == Collation::FALLBACK_CE32) {
1144                 UChar32 jamo = jamoCpFromIndex(j);
1145                 jamoCE32s[j] = copyFromBaseCE32(jamo, base->getCE32(jamo),
1146                                                 /*withContext=*/ TRUE, errorCode);
1147             }
1148         }
1149     }
1150     return anyJamoAssigned && U_SUCCESS(errorCode);
1151 }
1152
1153 void
1154 CollationDataBuilder::setDigitTags(UErrorCode &errorCode) {
1155     UnicodeSet digits(UNICODE_STRING_SIMPLE("[:Nd:]"), errorCode);
1156     if(U_FAILURE(errorCode)) { return; }
1157     UnicodeSetIterator iter(digits);
1158     while(iter.next()) {
1159         U_ASSERT(!iter.isString());
1160         UChar32 c = iter.getCodepoint();
1161         uint32_t ce32 = utrie2_get32(trie, c);
1162         if(ce32 != Collation::FALLBACK_CE32 && ce32 != Collation::UNASSIGNED_CE32) {
1163             int32_t index = addCE32(ce32, errorCode);
1164             if(U_FAILURE(errorCode)) { return; }
1165             if(index > Collation::MAX_INDEX) {
1166                 errorCode = U_BUFFER_OVERFLOW_ERROR;
1167                 return;
1168             }
1169             ce32 = Collation::makeCE32FromTagIndexAndLength(
1170                     Collation::DIGIT_TAG, index, u_charDigitValue(c));
1171             utrie2_set32(trie, c, ce32, &errorCode);
1172         }
1173     }
1174 }
1175
1176 U_CDECL_BEGIN
1177
1178 static UBool U_CALLCONV
1179 enumRangeLeadValue(const void *context, UChar32 /*start*/, UChar32 /*end*/, uint32_t value) {
1180     int32_t *pValue = (int32_t *)context;
1181     if(value == Collation::UNASSIGNED_CE32) {
1182         value = Collation::LEAD_ALL_UNASSIGNED;
1183     } else if(value == Collation::FALLBACK_CE32) {
1184         value = Collation::LEAD_ALL_FALLBACK;
1185     } else {
1186         *pValue = Collation::LEAD_MIXED;
1187         return FALSE;
1188     }
1189     if(*pValue < 0) {
1190         *pValue = (int32_t)value;
1191     } else if(*pValue != (int32_t)value) {
1192         *pValue = Collation::LEAD_MIXED;
1193         return FALSE;
1194     }
1195     return TRUE;
1196 }
1197
1198 U_CDECL_END
1199
1200 void
1201 CollationDataBuilder::setLeadSurrogates(UErrorCode &errorCode) {
1202     for(UChar lead = 0xd800; lead < 0xdc00; ++lead) {
1203         int32_t value = -1;
1204         utrie2_enumForLeadSurrogate(trie, lead, NULL, enumRangeLeadValue, &value);
1205         utrie2_set32ForLeadSurrogateCodeUnit(
1206             trie, lead,
1207             Collation::makeCE32FromTagAndIndex(Collation::LEAD_SURROGATE_TAG, 0) | (uint32_t)value,
1208             &errorCode);
1209     }
1210 }
1211
1212 void
1213 CollationDataBuilder::build(CollationData &data, UErrorCode &errorCode) {
1214     buildMappings(data, errorCode);
1215     if(base != NULL) {
1216         data.numericPrimary = base->numericPrimary;
1217         data.compressibleBytes = base->compressibleBytes;
1218         data.numScripts = base->numScripts;
1219         data.scriptsIndex = base->scriptsIndex;
1220         data.scriptStarts = base->scriptStarts;
1221         data.scriptStartsLength = base->scriptStartsLength;
1222     }
1223     buildFastLatinTable(data, errorCode);
1224 }
1225
1226 void
1227 CollationDataBuilder::buildMappings(CollationData &data, UErrorCode &errorCode) {
1228     if(U_FAILURE(errorCode)) { return; }
1229     if(trie == NULL || utrie2_isFrozen(trie)) {
1230         errorCode = U_INVALID_STATE_ERROR;
1231         return;
1232     }
1233
1234     buildContexts(errorCode);
1235
1236     uint32_t jamoCE32s[CollationData::JAMO_CE32S_LENGTH];
1237     int32_t jamoIndex = -1;
1238     if(getJamoCE32s(jamoCE32s, errorCode)) {
1239         jamoIndex = ce32s.size();
1240         for(int32_t i = 0; i < CollationData::JAMO_CE32S_LENGTH; ++i) {
1241             ce32s.addElement((int32_t)jamoCE32s[i], errorCode);
1242         }
1243         // Small optimization: Use a bit in the Hangul ce32
1244         // to indicate that none of the Jamo CE32s are isSpecialCE32()
1245         // (as it should be in the root collator).
1246         // It allows CollationIterator to avoid recursive function calls and per-Jamo tests.
1247         // In order to still have good trie compression and keep this code simple,
1248         // we only set this flag if a whole block of 588 Hangul syllables starting with
1249         // a common leading consonant (Jamo L) has this property.
1250         UBool isAnyJamoVTSpecial = FALSE;
1251         for(int32_t i = Hangul::JAMO_L_COUNT; i < CollationData::JAMO_CE32S_LENGTH; ++i) {
1252             if(Collation::isSpecialCE32(jamoCE32s[i])) {
1253                 isAnyJamoVTSpecial = TRUE;
1254                 break;
1255             }
1256         }
1257         uint32_t hangulCE32 = Collation::makeCE32FromTagAndIndex(Collation::HANGUL_TAG, 0);
1258         UChar32 c = Hangul::HANGUL_BASE;
1259         for(int32_t i = 0; i < Hangul::JAMO_L_COUNT; ++i) {  // iterate over the Jamo L
1260             uint32_t ce32 = hangulCE32;
1261             if(!isAnyJamoVTSpecial && !Collation::isSpecialCE32(jamoCE32s[i])) {
1262                 ce32 |= Collation::HANGUL_NO_SPECIAL_JAMO;
1263             }
1264             UChar32 limit = c + Hangul::JAMO_VT_COUNT;
1265             utrie2_setRange32(trie, c, limit - 1, ce32, TRUE, &errorCode);
1266             c = limit;
1267         }
1268     } else {
1269         // Copy the Hangul CE32s from the base in blocks per Jamo L,
1270         // assuming that HANGUL_NO_SPECIAL_JAMO is set or not set for whole blocks.
1271         for(UChar32 c = Hangul::HANGUL_BASE; c < Hangul::HANGUL_LIMIT;) {
1272             uint32_t ce32 = base->getCE32(c);
1273             U_ASSERT(Collation::hasCE32Tag(ce32, Collation::HANGUL_TAG));
1274             UChar32 limit = c + Hangul::JAMO_VT_COUNT;
1275             utrie2_setRange32(trie, c, limit - 1, ce32, TRUE, &errorCode);
1276             c = limit;
1277         }
1278     }
1279
1280     setDigitTags(errorCode);
1281     setLeadSurrogates(errorCode);
1282
1283     // For U+0000, move its normal ce32 into CE32s[0] and set U0000_TAG.
1284     ce32s.setElementAt((int32_t)utrie2_get32(trie, 0), 0);
1285     utrie2_set32(trie, 0, Collation::makeCE32FromTagAndIndex(Collation::U0000_TAG, 0), &errorCode);
1286
1287     utrie2_freeze(trie, UTRIE2_32_VALUE_BITS, &errorCode);
1288     if(U_FAILURE(errorCode)) { return; }
1289
1290     // Mark each lead surrogate as "unsafe"
1291     // if any of its 1024 associated supplementary code points is "unsafe".
1292     UChar32 c = 0x10000;
1293     for(UChar lead = 0xd800; lead < 0xdc00; ++lead, c += 0x400) {
1294         if(unsafeBackwardSet.containsSome(c, c + 0x3ff)) {
1295             unsafeBackwardSet.add(lead);
1296         }
1297     }
1298     unsafeBackwardSet.freeze();
1299
1300     data.trie = trie;
1301     data.ce32s = reinterpret_cast<const uint32_t *>(ce32s.getBuffer());
1302     data.ces = ce64s.getBuffer();
1303     data.contexts = contexts.getBuffer();
1304
1305     data.ce32sLength = ce32s.size();
1306     data.cesLength = ce64s.size();
1307     data.contextsLength = contexts.length();
1308
1309     data.base = base;
1310     if(jamoIndex >= 0) {
1311         data.jamoCE32s = data.ce32s + jamoIndex;
1312     } else {
1313         data.jamoCE32s = base->jamoCE32s;
1314     }
1315     data.unsafeBackwardSet = &unsafeBackwardSet;
1316 }
1317
1318 void
1319 CollationDataBuilder::clearContexts() {
1320     contexts.remove();
1321     UnicodeSetIterator iter(contextChars);
1322     while(iter.next()) {
1323         U_ASSERT(!iter.isString());
1324         uint32_t ce32 = utrie2_get32(trie, iter.getCodepoint());
1325         U_ASSERT(isBuilderContextCE32(ce32));
1326         getConditionalCE32ForCE32(ce32)->builtCE32 = Collation::NO_CE32;
1327     }
1328 }
1329
1330 void
1331 CollationDataBuilder::buildContexts(UErrorCode &errorCode) {
1332     if(U_FAILURE(errorCode)) { return; }
1333     // Ignore abandoned lists and the cached builtCE32,
1334     // and build all contexts from scratch.
1335     contexts.remove();
1336     UnicodeSetIterator iter(contextChars);
1337     while(U_SUCCESS(errorCode) && iter.next()) {
1338         U_ASSERT(!iter.isString());
1339         UChar32 c = iter.getCodepoint();
1340         uint32_t ce32 = utrie2_get32(trie, c);
1341         if(!isBuilderContextCE32(ce32)) {
1342             // Impossible: No context data for c in contextChars.
1343             errorCode = U_INTERNAL_PROGRAM_ERROR;
1344             return;
1345         }
1346         ConditionalCE32 *cond = getConditionalCE32ForCE32(ce32);
1347         ce32 = buildContext(cond, errorCode);
1348         utrie2_set32(trie, c, ce32, &errorCode);
1349     }
1350 }
1351
1352 uint32_t
1353 CollationDataBuilder::buildContext(ConditionalCE32 *head, UErrorCode &errorCode) {
1354     if(U_FAILURE(errorCode)) { return 0; }
1355     // The list head must have no context.
1356     U_ASSERT(!head->hasContext());
1357     // The list head must be followed by one or more nodes that all do have context.
1358     U_ASSERT(head->next >= 0);
1359     UCharsTrieBuilder prefixBuilder(errorCode);
1360     UCharsTrieBuilder contractionBuilder(errorCode);
1361     for(ConditionalCE32 *cond = head;; cond = getConditionalCE32(cond->next)) {
1362         // After the list head, the prefix or suffix can be empty, but not both.
1363         U_ASSERT(cond == head || cond->hasContext());
1364         int32_t prefixLength = cond->prefixLength();
1365         UnicodeString prefix(cond->context, 0, prefixLength + 1);
1366         // Collect all contraction suffixes for one prefix.
1367         ConditionalCE32 *firstCond = cond;
1368         ConditionalCE32 *lastCond = cond;
1369         while(cond->next >= 0 &&
1370                 (cond = getConditionalCE32(cond->next))->context.startsWith(prefix)) {
1371             lastCond = cond;
1372         }
1373         uint32_t ce32;
1374         int32_t suffixStart = prefixLength + 1;  // == prefix.length()
1375         if(lastCond->context.length() == suffixStart) {
1376             // One prefix without contraction suffix.
1377             U_ASSERT(firstCond == lastCond);
1378             ce32 = lastCond->ce32;
1379             cond = lastCond;
1380         } else {
1381             // Build the contractions trie.
1382             contractionBuilder.clear();
1383             // Entry for an empty suffix, to be stored before the trie.
1384             uint32_t emptySuffixCE32 = 0;
1385             uint32_t flags = 0;
1386             if(firstCond->context.length() == suffixStart) {
1387                 // There is a mapping for the prefix and the single character c. (p|c)
1388                 // If no other suffix matches, then we return this value.
1389                 emptySuffixCE32 = firstCond->ce32;
1390                 cond = getConditionalCE32(firstCond->next);
1391             } else {
1392                 // There is no mapping for the prefix and just the single character.
1393                 // (There is no p|c, only p|cd, p|ce etc.)
1394                 flags |= Collation::CONTRACT_SINGLE_CP_NO_MATCH;
1395                 // When the prefix matches but none of the prefix-specific suffixes,
1396                 // then we fall back to the mappings with the next-longest prefix,
1397                 // and ultimately to mappings with no prefix.
1398                 // Each fallback might be another set of contractions.
1399                 // For example, if there are mappings for ch, p|cd, p|ce, but not for p|c,
1400                 // then in text "pch" we find the ch contraction.
1401                 for(cond = head;; cond = getConditionalCE32(cond->next)) {
1402                     int32_t length = cond->prefixLength();
1403                     if(length == prefixLength) { break; }
1404                     if(cond->defaultCE32 != Collation::NO_CE32 &&
1405                             (length==0 || prefix.endsWith(cond->context, 1, length))) {
1406                         emptySuffixCE32 = cond->defaultCE32;
1407                     }
1408                 }
1409                 cond = firstCond;
1410             }
1411             // Optimization: Set a flag when
1412             // the first character of every contraction suffix has lccc!=0.
1413             // Short-circuits contraction matching when a normal letter follows.
1414             flags |= Collation::CONTRACT_NEXT_CCC;
1415             // Add all of the non-empty suffixes into the contraction trie.
1416             for(;;) {
1417                 UnicodeString suffix(cond->context, suffixStart);
1418                 uint16_t fcd16 = nfcImpl.getFCD16(suffix.char32At(0));
1419                 if(fcd16 <= 0xff) {
1420                     flags &= ~Collation::CONTRACT_NEXT_CCC;
1421                 }
1422                 fcd16 = nfcImpl.getFCD16(suffix.char32At(suffix.length() - 1));
1423                 if(fcd16 > 0xff) {
1424                     // The last suffix character has lccc!=0, allowing for discontiguous contractions.
1425                     flags |= Collation::CONTRACT_TRAILING_CCC;
1426                 }
1427                 contractionBuilder.add(suffix, (int32_t)cond->ce32, errorCode);
1428                 if(cond == lastCond) { break; }
1429                 cond = getConditionalCE32(cond->next);
1430             }
1431             int32_t index = addContextTrie(emptySuffixCE32, contractionBuilder, errorCode);
1432             if(U_FAILURE(errorCode)) { return 0; }
1433             if(index > Collation::MAX_INDEX) {
1434                 errorCode = U_BUFFER_OVERFLOW_ERROR;
1435                 return 0;
1436             }
1437             ce32 = Collation::makeCE32FromTagAndIndex(Collation::CONTRACTION_TAG, index) | flags;
1438         }
1439         U_ASSERT(cond == lastCond);
1440         firstCond->defaultCE32 = ce32;
1441         if(prefixLength == 0) {
1442             if(cond->next < 0) {
1443                 // No non-empty prefixes, only contractions.
1444                 return ce32;
1445             }
1446         } else {
1447             prefix.remove(0, 1);  // Remove the length unit.
1448             prefix.reverse();
1449             prefixBuilder.add(prefix, (int32_t)ce32, errorCode);
1450             if(cond->next < 0) { break; }
1451         }
1452     }
1453     U_ASSERT(head->defaultCE32 != Collation::NO_CE32);
1454     int32_t index = addContextTrie(head->defaultCE32, prefixBuilder, errorCode);
1455     if(U_FAILURE(errorCode)) { return 0; }
1456     if(index > Collation::MAX_INDEX) {
1457         errorCode = U_BUFFER_OVERFLOW_ERROR;
1458         return 0;
1459     }
1460     return Collation::makeCE32FromTagAndIndex(Collation::PREFIX_TAG, index);
1461 }
1462
1463 int32_t
1464 CollationDataBuilder::addContextTrie(uint32_t defaultCE32, UCharsTrieBuilder &trieBuilder,
1465                                      UErrorCode &errorCode) {
1466     UnicodeString context;
1467     context.append((UChar)(defaultCE32 >> 16)).append((UChar)defaultCE32);
1468     UnicodeString trieString;
1469     context.append(trieBuilder.buildUnicodeString(USTRINGTRIE_BUILD_SMALL, trieString, errorCode));
1470     if(U_FAILURE(errorCode)) { return -1; }
1471     int32_t index = contexts.indexOf(context);
1472     if(index < 0) {
1473         index = contexts.length();
1474         contexts.append(context);
1475     }
1476     return index;
1477 }
1478
1479 void
1480 CollationDataBuilder::buildFastLatinTable(CollationData &data, UErrorCode &errorCode) {
1481     if(U_FAILURE(errorCode) || !fastLatinEnabled) { return; }
1482
1483     delete fastLatinBuilder;
1484     fastLatinBuilder = new CollationFastLatinBuilder(errorCode);
1485     if(fastLatinBuilder == NULL) {
1486         errorCode = U_MEMORY_ALLOCATION_ERROR;
1487         return;
1488     }
1489     if(fastLatinBuilder->forData(data, errorCode)) {
1490         const uint16_t *table = fastLatinBuilder->getTable();
1491         int32_t length = fastLatinBuilder->lengthOfTable();
1492         if(base != NULL && length == base->fastLatinTableLength &&
1493                 uprv_memcmp(table, base->fastLatinTable, length * 2) == 0) {
1494             // Same fast Latin table as in the base, use that one instead.
1495             delete fastLatinBuilder;
1496             fastLatinBuilder = NULL;
1497             table = base->fastLatinTable;
1498         }
1499         data.fastLatinTable = table;
1500         data.fastLatinTableLength = length;
1501     } else {
1502         delete fastLatinBuilder;
1503         fastLatinBuilder = NULL;
1504     }
1505 }
1506
1507 int32_t
1508 CollationDataBuilder::getCEs(const UnicodeString &s, int64_t ces[], int32_t cesLength) {
1509     return getCEs(s, 0, ces, cesLength);
1510 }
1511
1512 int32_t
1513 CollationDataBuilder::getCEs(const UnicodeString &prefix, const UnicodeString &s,
1514                              int64_t ces[], int32_t cesLength) {
1515     int32_t prefixLength = prefix.length();
1516     if(prefixLength == 0) {
1517         return getCEs(s, 0, ces, cesLength);
1518     } else {
1519         return getCEs(prefix + s, prefixLength, ces, cesLength);
1520     }
1521 }
1522
1523 int32_t
1524 CollationDataBuilder::getCEs(const UnicodeString &s, int32_t start,
1525                              int64_t ces[], int32_t cesLength) {
1526     if(collIter == NULL) {
1527         collIter = new DataBuilderCollationIterator(*this);
1528         if(collIter == NULL) { return 0; }
1529     }
1530     return collIter->fetchCEs(s, start, ces, cesLength);
1531 }
1532
1533 U_NAMESPACE_END
1534
1535 #endif  // !UCONFIG_NO_COLLATION