1 // © 2016 and later: Unicode, Inc. and others. 2 // License & terms of use: http://www.unicode.org/copyright.html 3 /* 4 ******************************************************************************* 5 * Copyright (C) 2010-2012, International Business Machines 6 * Corporation and others. All Rights Reserved. 7 ******************************************************************************* 8 * file name: ucharstrie.h 9 * encoding: UTF-8 10 * tab size: 8 (not used) 11 * indentation:4 12 * 13 * created on: 2010nov14 14 * created by: Markus W. Scherer 15 */ 16 17 #ifndef __UCHARSTRIE_H__ 18 #define __UCHARSTRIE_H__ 19 20 /** 21 * \file 22 * \brief C++ API: Trie for mapping Unicode strings (or 16-bit-unit sequences) 23 * to integer values. 24 */ 25 26 #include "unicode/utypes.h" 27 28 #if U_SHOW_CPLUSPLUS_API 29 30 #include "unicode/unistr.h" 31 #include "unicode/uobject.h" 32 #include "unicode/ustringtrie.h" 33 34 U_NAMESPACE_BEGIN 35 36 class Appendable; 37 class UCharsTrieBuilder; 38 class UVector32; 39 40 /** 41 * Light-weight, non-const reader class for a UCharsTrie. 42 * Traverses a char16_t-serialized data structure with minimal state, 43 * for mapping strings (16-bit-unit sequences) to non-negative integer values. 44 * 45 * This class owns the serialized trie data only if it was constructed by 46 * the builder's build() method. 47 * The public constructor and the copy constructor only alias the data (only copy the pointer). 48 * There is no assignment operator. 49 * 50 * This class is not intended for public subclassing. 51 * @stable ICU 4.8 52 */ 53 class U_COMMON_API UCharsTrie : public UMemory { 54 public: 55 /** 56 * Constructs a UCharsTrie reader instance. 57 * 58 * The trieUChars must contain a copy of a char16_t sequence from the UCharsTrieBuilder, 59 * starting with the first char16_t of that sequence. 60 * The UCharsTrie object will not read more char16_ts than 61 * the UCharsTrieBuilder generated in the corresponding build() call. 62 * 63 * The array is not copied/cloned and must not be modified while 64 * the UCharsTrie object is in use. 65 * 66 * @param trieUChars The char16_t array that contains the serialized trie. 67 * @stable ICU 4.8 68 */ UCharsTrie(ConstChar16Ptr trieUChars)69 UCharsTrie(ConstChar16Ptr trieUChars) 70 : ownedArray_(NULL), uchars_(trieUChars), 71 pos_(uchars_), remainingMatchLength_(-1) {} 72 73 /** 74 * Destructor. 75 * @stable ICU 4.8 76 */ 77 ~UCharsTrie(); 78 79 /** 80 * Copy constructor, copies the other trie reader object and its state, 81 * but not the char16_t array which will be shared. (Shallow copy.) 82 * @param other Another UCharsTrie object. 83 * @stable ICU 4.8 84 */ UCharsTrie(const UCharsTrie & other)85 UCharsTrie(const UCharsTrie &other) 86 : ownedArray_(NULL), uchars_(other.uchars_), 87 pos_(other.pos_), remainingMatchLength_(other.remainingMatchLength_) {} 88 89 /** 90 * Resets this trie to its initial state. 91 * @return *this 92 * @stable ICU 4.8 93 */ reset()94 UCharsTrie &reset() { 95 pos_=uchars_; 96 remainingMatchLength_=-1; 97 return *this; 98 } 99 100 #ifndef U_HIDE_DRAFT_API 101 /** 102 * Returns the state of this trie as a 64-bit integer. 103 * The state value is never 0. 104 * 105 * @return opaque state value 106 * @see resetToState64 107 * @draft ICU 65 108 */ getState64()109 uint64_t getState64() const { 110 return (static_cast<uint64_t>(remainingMatchLength_ + 2) << kState64RemainingShift) | 111 (uint64_t)(pos_ - uchars_); 112 } 113 114 /** 115 * Resets this trie to the saved state. 116 * Unlike resetToState(State), the 64-bit state value 117 * must be from getState64() from the same trie object or 118 * from one initialized the exact same way. 119 * Because of no validation, this method is faster. 120 * 121 * @param state The opaque trie state value from getState64(). 122 * @return *this 123 * @see getState64 124 * @see resetToState 125 * @see reset 126 * @draft ICU 65 127 */ resetToState64(uint64_t state)128 UCharsTrie &resetToState64(uint64_t state) { 129 remainingMatchLength_ = static_cast<int32_t>(state >> kState64RemainingShift) - 2; 130 pos_ = uchars_ + (state & kState64PosMask); 131 return *this; 132 } 133 #endif /* U_HIDE_DRAFT_API */ 134 135 /** 136 * UCharsTrie state object, for saving a trie's current state 137 * and resetting the trie back to this state later. 138 * @stable ICU 4.8 139 */ 140 class State : public UMemory { 141 public: 142 /** 143 * Constructs an empty State. 144 * @stable ICU 4.8 145 */ State()146 State() { uchars=NULL; } 147 private: 148 friend class UCharsTrie; 149 150 const char16_t *uchars; 151 const char16_t *pos; 152 int32_t remainingMatchLength; 153 }; 154 155 /** 156 * Saves the state of this trie. 157 * @param state The State object to hold the trie's state. 158 * @return *this 159 * @see resetToState 160 * @stable ICU 4.8 161 */ saveState(State & state)162 const UCharsTrie &saveState(State &state) const { 163 state.uchars=uchars_; 164 state.pos=pos_; 165 state.remainingMatchLength=remainingMatchLength_; 166 return *this; 167 } 168 169 /** 170 * Resets this trie to the saved state. 171 * If the state object contains no state, or the state of a different trie, 172 * then this trie remains unchanged. 173 * @param state The State object which holds a saved trie state. 174 * @return *this 175 * @see saveState 176 * @see reset 177 * @stable ICU 4.8 178 */ resetToState(const State & state)179 UCharsTrie &resetToState(const State &state) { 180 if(uchars_==state.uchars && uchars_!=NULL) { 181 pos_=state.pos; 182 remainingMatchLength_=state.remainingMatchLength; 183 } 184 return *this; 185 } 186 187 /** 188 * Determines whether the string so far matches, whether it has a value, 189 * and whether another input char16_t can continue a matching string. 190 * @return The match/value Result. 191 * @stable ICU 4.8 192 */ 193 UStringTrieResult current() const; 194 195 /** 196 * Traverses the trie from the initial state for this input char16_t. 197 * Equivalent to reset().next(uchar). 198 * @param uchar Input char value. Values below 0 and above 0xffff will never match. 199 * @return The match/value Result. 200 * @stable ICU 4.8 201 */ first(int32_t uchar)202 inline UStringTrieResult first(int32_t uchar) { 203 remainingMatchLength_=-1; 204 return nextImpl(uchars_, uchar); 205 } 206 207 /** 208 * Traverses the trie from the initial state for the 209 * one or two UTF-16 code units for this input code point. 210 * Equivalent to reset().nextForCodePoint(cp). 211 * @param cp A Unicode code point 0..0x10ffff. 212 * @return The match/value Result. 213 * @stable ICU 4.8 214 */ 215 UStringTrieResult firstForCodePoint(UChar32 cp); 216 217 /** 218 * Traverses the trie from the current state for this input char16_t. 219 * @param uchar Input char value. Values below 0 and above 0xffff will never match. 220 * @return The match/value Result. 221 * @stable ICU 4.8 222 */ 223 UStringTrieResult next(int32_t uchar); 224 225 /** 226 * Traverses the trie from the current state for the 227 * one or two UTF-16 code units for this input code point. 228 * @param cp A Unicode code point 0..0x10ffff. 229 * @return The match/value Result. 230 * @stable ICU 4.8 231 */ 232 UStringTrieResult nextForCodePoint(UChar32 cp); 233 234 /** 235 * Traverses the trie from the current state for this string. 236 * Equivalent to 237 * \code 238 * Result result=current(); 239 * for(each c in s) 240 * if(!USTRINGTRIE_HAS_NEXT(result)) return USTRINGTRIE_NO_MATCH; 241 * result=next(c); 242 * return result; 243 * \endcode 244 * @param s A string. Can be NULL if length is 0. 245 * @param length The length of the string. Can be -1 if NUL-terminated. 246 * @return The match/value Result. 247 * @stable ICU 4.8 248 */ 249 UStringTrieResult next(ConstChar16Ptr s, int32_t length); 250 251 /** 252 * Returns a matching string's value if called immediately after 253 * current()/first()/next() returned USTRINGTRIE_INTERMEDIATE_VALUE or USTRINGTRIE_FINAL_VALUE. 254 * getValue() can be called multiple times. 255 * 256 * Do not call getValue() after USTRINGTRIE_NO_MATCH or USTRINGTRIE_NO_VALUE! 257 * @return The value for the string so far. 258 * @stable ICU 4.8 259 */ getValue()260 inline int32_t getValue() const { 261 const char16_t *pos=pos_; 262 int32_t leadUnit=*pos++; 263 // U_ASSERT(leadUnit>=kMinValueLead); 264 return leadUnit&kValueIsFinal ? 265 readValue(pos, leadUnit&0x7fff) : readNodeValue(pos, leadUnit); 266 } 267 268 /** 269 * Determines whether all strings reachable from the current state 270 * map to the same value. 271 * @param uniqueValue Receives the unique value, if this function returns TRUE. 272 * (output-only) 273 * @return TRUE if all strings reachable from the current state 274 * map to the same value. 275 * @stable ICU 4.8 276 */ hasUniqueValue(int32_t & uniqueValue)277 inline UBool hasUniqueValue(int32_t &uniqueValue) const { 278 const char16_t *pos=pos_; 279 // Skip the rest of a pending linear-match node. 280 return pos!=NULL && findUniqueValue(pos+remainingMatchLength_+1, FALSE, uniqueValue); 281 } 282 283 /** 284 * Finds each char16_t which continues the string from the current state. 285 * That is, each char16_t c for which it would be next(c)!=USTRINGTRIE_NO_MATCH now. 286 * @param out Each next char16_t is appended to this object. 287 * @return the number of char16_ts which continue the string from here 288 * @stable ICU 4.8 289 */ 290 int32_t getNextUChars(Appendable &out) const; 291 292 /** 293 * Iterator for all of the (string, value) pairs in a UCharsTrie. 294 * @stable ICU 4.8 295 */ 296 class U_COMMON_API Iterator : public UMemory { 297 public: 298 /** 299 * Iterates from the root of a char16_t-serialized UCharsTrie. 300 * @param trieUChars The trie char16_ts. 301 * @param maxStringLength If 0, the iterator returns full strings. 302 * Otherwise, the iterator returns strings with this maximum length. 303 * @param errorCode Standard ICU error code. Its input value must 304 * pass the U_SUCCESS() test, or else the function returns 305 * immediately. Check for U_FAILURE() on output or use with 306 * function chaining. (See User Guide for details.) 307 * @stable ICU 4.8 308 */ 309 Iterator(ConstChar16Ptr trieUChars, int32_t maxStringLength, UErrorCode &errorCode); 310 311 /** 312 * Iterates from the current state of the specified UCharsTrie. 313 * @param trie The trie whose state will be copied for iteration. 314 * @param maxStringLength If 0, the iterator returns full strings. 315 * Otherwise, the iterator returns strings with this maximum length. 316 * @param errorCode Standard ICU error code. Its input value must 317 * pass the U_SUCCESS() test, or else the function returns 318 * immediately. Check for U_FAILURE() on output or use with 319 * function chaining. (See User Guide for details.) 320 * @stable ICU 4.8 321 */ 322 Iterator(const UCharsTrie &trie, int32_t maxStringLength, UErrorCode &errorCode); 323 324 /** 325 * Destructor. 326 * @stable ICU 4.8 327 */ 328 ~Iterator(); 329 330 /** 331 * Resets this iterator to its initial state. 332 * @return *this 333 * @stable ICU 4.8 334 */ 335 Iterator &reset(); 336 337 /** 338 * @return TRUE if there are more elements. 339 * @stable ICU 4.8 340 */ 341 UBool hasNext() const; 342 343 /** 344 * Finds the next (string, value) pair if there is one. 345 * 346 * If the string is truncated to the maximum length and does not 347 * have a real value, then the value is set to -1. 348 * In this case, this "not a real value" is indistinguishable from 349 * a real value of -1. 350 * @param errorCode Standard ICU error code. Its input value must 351 * pass the U_SUCCESS() test, or else the function returns 352 * immediately. Check for U_FAILURE() on output or use with 353 * function chaining. (See User Guide for details.) 354 * @return TRUE if there is another element. 355 * @stable ICU 4.8 356 */ 357 UBool next(UErrorCode &errorCode); 358 359 /** 360 * @return The string for the last successful next(). 361 * @stable ICU 4.8 362 */ getString()363 const UnicodeString &getString() const { return str_; } 364 /** 365 * @return The value for the last successful next(). 366 * @stable ICU 4.8 367 */ getValue()368 int32_t getValue() const { return value_; } 369 370 private: truncateAndStop()371 UBool truncateAndStop() { 372 pos_=NULL; 373 value_=-1; // no real value for str 374 return TRUE; 375 } 376 377 const char16_t *branchNext(const char16_t *pos, int32_t length, UErrorCode &errorCode); 378 379 const char16_t *uchars_; 380 const char16_t *pos_; 381 const char16_t *initialPos_; 382 int32_t remainingMatchLength_; 383 int32_t initialRemainingMatchLength_; 384 UBool skipValue_; // Skip intermediate value which was already delivered. 385 386 UnicodeString str_; 387 int32_t maxLength_; 388 int32_t value_; 389 390 // The stack stores pairs of integers for backtracking to another 391 // outbound edge of a branch node. 392 // The first integer is an offset from uchars_. 393 // The second integer has the str_.length() from before the node in bits 15..0, 394 // and the remaining branch length in bits 31..16. 395 // (We could store the remaining branch length minus 1 in bits 30..16 and not use the sign bit, 396 // but the code looks more confusing that way.) 397 UVector32 *stack_; 398 }; 399 400 private: 401 friend class UCharsTrieBuilder; 402 403 /** 404 * Constructs a UCharsTrie reader instance. 405 * Unlike the public constructor which just aliases an array, 406 * this constructor adopts the builder's array. 407 * This constructor is only called by the builder. 408 */ UCharsTrie(char16_t * adoptUChars,const char16_t * trieUChars)409 UCharsTrie(char16_t *adoptUChars, const char16_t *trieUChars) 410 : ownedArray_(adoptUChars), uchars_(trieUChars), 411 pos_(uchars_), remainingMatchLength_(-1) {} 412 413 // No assignment operator. 414 UCharsTrie &operator=(const UCharsTrie &other); 415 stop()416 inline void stop() { 417 pos_=NULL; 418 } 419 420 // Reads a compact 32-bit integer. 421 // pos is already after the leadUnit, and the lead unit has bit 15 reset. readValue(const char16_t * pos,int32_t leadUnit)422 static inline int32_t readValue(const char16_t *pos, int32_t leadUnit) { 423 int32_t value; 424 if(leadUnit<kMinTwoUnitValueLead) { 425 value=leadUnit; 426 } else if(leadUnit<kThreeUnitValueLead) { 427 value=((leadUnit-kMinTwoUnitValueLead)<<16)|*pos; 428 } else { 429 value=(pos[0]<<16)|pos[1]; 430 } 431 return value; 432 } skipValue(const char16_t * pos,int32_t leadUnit)433 static inline const char16_t *skipValue(const char16_t *pos, int32_t leadUnit) { 434 if(leadUnit>=kMinTwoUnitValueLead) { 435 if(leadUnit<kThreeUnitValueLead) { 436 ++pos; 437 } else { 438 pos+=2; 439 } 440 } 441 return pos; 442 } skipValue(const char16_t * pos)443 static inline const char16_t *skipValue(const char16_t *pos) { 444 int32_t leadUnit=*pos++; 445 return skipValue(pos, leadUnit&0x7fff); 446 } 447 readNodeValue(const char16_t * pos,int32_t leadUnit)448 static inline int32_t readNodeValue(const char16_t *pos, int32_t leadUnit) { 449 // U_ASSERT(kMinValueLead<=leadUnit && leadUnit<kValueIsFinal); 450 int32_t value; 451 if(leadUnit<kMinTwoUnitNodeValueLead) { 452 value=(leadUnit>>6)-1; 453 } else if(leadUnit<kThreeUnitNodeValueLead) { 454 value=(((leadUnit&0x7fc0)-kMinTwoUnitNodeValueLead)<<10)|*pos; 455 } else { 456 value=(pos[0]<<16)|pos[1]; 457 } 458 return value; 459 } skipNodeValue(const char16_t * pos,int32_t leadUnit)460 static inline const char16_t *skipNodeValue(const char16_t *pos, int32_t leadUnit) { 461 // U_ASSERT(kMinValueLead<=leadUnit && leadUnit<kValueIsFinal); 462 if(leadUnit>=kMinTwoUnitNodeValueLead) { 463 if(leadUnit<kThreeUnitNodeValueLead) { 464 ++pos; 465 } else { 466 pos+=2; 467 } 468 } 469 return pos; 470 } 471 jumpByDelta(const char16_t * pos)472 static inline const char16_t *jumpByDelta(const char16_t *pos) { 473 int32_t delta=*pos++; 474 if(delta>=kMinTwoUnitDeltaLead) { 475 if(delta==kThreeUnitDeltaLead) { 476 delta=(pos[0]<<16)|pos[1]; 477 pos+=2; 478 } else { 479 delta=((delta-kMinTwoUnitDeltaLead)<<16)|*pos++; 480 } 481 } 482 return pos+delta; 483 } 484 skipDelta(const char16_t * pos)485 static const char16_t *skipDelta(const char16_t *pos) { 486 int32_t delta=*pos++; 487 if(delta>=kMinTwoUnitDeltaLead) { 488 if(delta==kThreeUnitDeltaLead) { 489 pos+=2; 490 } else { 491 ++pos; 492 } 493 } 494 return pos; 495 } 496 valueResult(int32_t node)497 static inline UStringTrieResult valueResult(int32_t node) { 498 return (UStringTrieResult)(USTRINGTRIE_INTERMEDIATE_VALUE-(node>>15)); 499 } 500 501 // Handles a branch node for both next(uchar) and next(string). 502 UStringTrieResult branchNext(const char16_t *pos, int32_t length, int32_t uchar); 503 504 // Requires remainingLength_<0. 505 UStringTrieResult nextImpl(const char16_t *pos, int32_t uchar); 506 507 // Helper functions for hasUniqueValue(). 508 // Recursively finds a unique value (or whether there is not a unique one) 509 // from a branch. 510 static const char16_t *findUniqueValueFromBranch(const char16_t *pos, int32_t length, 511 UBool haveUniqueValue, int32_t &uniqueValue); 512 // Recursively finds a unique value (or whether there is not a unique one) 513 // starting from a position on a node lead unit. 514 static UBool findUniqueValue(const char16_t *pos, UBool haveUniqueValue, int32_t &uniqueValue); 515 516 // Helper functions for getNextUChars(). 517 // getNextUChars() when pos is on a branch node. 518 static void getNextBranchUChars(const char16_t *pos, int32_t length, Appendable &out); 519 520 // UCharsTrie data structure 521 // 522 // The trie consists of a series of char16_t-serialized nodes for incremental 523 // Unicode string/char16_t sequence matching. (char16_t=16-bit unsigned integer) 524 // The root node is at the beginning of the trie data. 525 // 526 // Types of nodes are distinguished by their node lead unit ranges. 527 // After each node, except a final-value node, another node follows to 528 // encode match values or continue matching further units. 529 // 530 // Node types: 531 // - Final-value node: Stores a 32-bit integer in a compact, variable-length format. 532 // The value is for the string/char16_t sequence so far. 533 // - Match node, optionally with an intermediate value in a different compact format. 534 // The value, if present, is for the string/char16_t sequence so far. 535 // 536 // Aside from the value, which uses the node lead unit's high bits: 537 // 538 // - Linear-match node: Matches a number of units. 539 // - Branch node: Branches to other nodes according to the current input unit. 540 // The node unit is the length of the branch (number of units to select from) 541 // minus 1. It is followed by a sub-node: 542 // - If the length is at most kMaxBranchLinearSubNodeLength, then 543 // there are length-1 (key, value) pairs and then one more comparison unit. 544 // If one of the key units matches, then the value is either a final value for 545 // the string so far, or a "jump" delta to the next node. 546 // If the last unit matches, then matching continues with the next node. 547 // (Values have the same encoding as final-value nodes.) 548 // - If the length is greater than kMaxBranchLinearSubNodeLength, then 549 // there is one unit and one "jump" delta. 550 // If the input unit is less than the sub-node unit, then "jump" by delta to 551 // the next sub-node which will have a length of length/2. 552 // (The delta has its own compact encoding.) 553 // Otherwise, skip the "jump" delta to the next sub-node 554 // which will have a length of length-length/2. 555 556 // Match-node lead unit values, after masking off intermediate-value bits: 557 558 // 0000..002f: Branch node. If node!=0 then the length is node+1, otherwise 559 // the length is one more than the next unit. 560 561 // For a branch sub-node with at most this many entries, we drop down 562 // to a linear search. 563 static const int32_t kMaxBranchLinearSubNodeLength=5; 564 565 // 0030..003f: Linear-match node, match 1..16 units and continue reading the next node. 566 static const int32_t kMinLinearMatch=0x30; 567 static const int32_t kMaxLinearMatchLength=0x10; 568 569 // Match-node lead unit bits 14..6 for the optional intermediate value. 570 // If these bits are 0, then there is no intermediate value. 571 // Otherwise, see the *NodeValue* constants below. 572 static const int32_t kMinValueLead=kMinLinearMatch+kMaxLinearMatchLength; // 0x0040 573 static const int32_t kNodeTypeMask=kMinValueLead-1; // 0x003f 574 575 // A final-value node has bit 15 set. 576 static const int32_t kValueIsFinal=0x8000; 577 578 // Compact value: After testing and masking off bit 15, use the following thresholds. 579 static const int32_t kMaxOneUnitValue=0x3fff; 580 581 static const int32_t kMinTwoUnitValueLead=kMaxOneUnitValue+1; // 0x4000 582 static const int32_t kThreeUnitValueLead=0x7fff; 583 584 static const int32_t kMaxTwoUnitValue=((kThreeUnitValueLead-kMinTwoUnitValueLead)<<16)-1; // 0x3ffeffff 585 586 // Compact intermediate-value integer, lead unit shared with a branch or linear-match node. 587 static const int32_t kMaxOneUnitNodeValue=0xff; 588 static const int32_t kMinTwoUnitNodeValueLead=kMinValueLead+((kMaxOneUnitNodeValue+1)<<6); // 0x4040 589 static const int32_t kThreeUnitNodeValueLead=0x7fc0; 590 591 static const int32_t kMaxTwoUnitNodeValue= 592 ((kThreeUnitNodeValueLead-kMinTwoUnitNodeValueLead)<<10)-1; // 0xfdffff 593 594 // Compact delta integers. 595 static const int32_t kMaxOneUnitDelta=0xfbff; 596 static const int32_t kMinTwoUnitDeltaLead=kMaxOneUnitDelta+1; // 0xfc00 597 static const int32_t kThreeUnitDeltaLead=0xffff; 598 599 static const int32_t kMaxTwoUnitDelta=((kThreeUnitDeltaLead-kMinTwoUnitDeltaLead)<<16)-1; // 0x03feffff 600 601 // For getState64(): 602 // The remainingMatchLength_ is -1..14=(kMaxLinearMatchLength=0x10)-2 603 // so we need at least 5 bits for that. 604 // We add 2 to store it as a positive value 1..16=kMaxLinearMatchLength. 605 static constexpr int32_t kState64RemainingShift = 59; 606 static constexpr uint64_t kState64PosMask = (UINT64_C(1) << kState64RemainingShift) - 1; 607 608 char16_t *ownedArray_; 609 610 // Fixed value referencing the UCharsTrie words. 611 const char16_t *uchars_; 612 613 // Iterator variables. 614 615 // Pointer to next trie unit to read. NULL if no more matches. 616 const char16_t *pos_; 617 // Remaining length of a linear-match node, minus 1. Negative if not in such a node. 618 int32_t remainingMatchLength_; 619 }; 620 621 U_NAMESPACE_END 622 623 #endif /* U_SHOW_CPLUSPLUS_API */ 624 625 #endif // __UCHARSTRIE_H__ 626