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ucharstrie.h
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1 // Copyright (C) 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: US-ASCII
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
26 #include "unicode/utypes.h"
27 #include "unicode/unistr.h"
28 #include "unicode/uobject.h"
29 #include "unicode/ustringtrie.h"
30
31 U_NAMESPACE_BEGIN
32
33 class Appendable;
34 class UCharsTrieBuilder;
35 class UVector32;
36
50 class U_COMMON_API UCharsTrie : public UMemory {
51 public:
66 UCharsTrie(const UChar *trieUChars)
67 : ownedArray_(NULL), uchars_(trieUChars),
68 pos_(uchars_), remainingMatchLength_(-1) {}
69
74 ~UCharsTrie();
75
82 UCharsTrie(const UCharsTrie &other)
83 : ownedArray_(NULL), uchars_(other.uchars_),
84 pos_(other.pos_), remainingMatchLength_(other.remainingMatchLength_) {}
85
91 UCharsTrie &reset() {
92 pos_=uchars_;
93 remainingMatchLength_=-1;
94 return *this;
95 }
96
102 class State : public UMemory {
103 public:
108 State() { uchars=NULL; }
109 private:
110 friend class UCharsTrie;
111
112 const UChar *uchars;
113 const UChar *pos;
114 int32_t remainingMatchLength;
115 };
116
124 const UCharsTrie &saveState(State &state) const {
125 state.uchars=uchars_;
126 state.pos=pos_;
127 state.remainingMatchLength=remainingMatchLength_;
128 return *this;
129 }
130
141 UCharsTrie &resetToState(const State &state) {
142 if(uchars_==state.uchars && uchars_!=NULL) {
143 pos_=state.pos;
144 remainingMatchLength_=state.remainingMatchLength;
145 }
146 return *this;
147 }
148
155 UStringTrieResult current() const;
156
164 inline UStringTrieResult first(int32_t uchar) {
165 remainingMatchLength_=-1;
166 return nextImpl(uchars_, uchar);
167 }
168
177 UStringTrieResult firstForCodePoint(UChar32 cp);
178
185 UStringTrieResult next(int32_t uchar);
186
194 UStringTrieResult nextForCodePoint(UChar32 cp);
195
211 UStringTrieResult next(const UChar *s, int32_t length);
212
222 inline int32_t getValue() const {
223 const UChar *pos=pos_;
224 int32_t leadUnit=*pos++;
225 // U_ASSERT(leadUnit>=kMinValueLead);
226 return leadUnit&kValueIsFinal ?
227 readValue(pos, leadUnit&0x7fff) : readNodeValue(pos, leadUnit);
228 }
229
239 inline UBool hasUniqueValue(int32_t &uniqueValue) const {
240 const UChar *pos=pos_;
241 // Skip the rest of a pending linear-match node.
242 return pos!=NULL && findUniqueValue(pos+remainingMatchLength_+1, FALSE, uniqueValue);
243 }
244
252 int32_t getNextUChars(Appendable &out) const;
253
258 class U_COMMON_API Iterator : public UMemory {
259 public:
271 Iterator(const UChar *trieUChars, int32_t maxStringLength, UErrorCode &errorCode);
272
284 Iterator(const UCharsTrie &trie, int32_t maxStringLength, UErrorCode &errorCode);
285
290 ~Iterator();
291
297 Iterator &reset();
298
303 UBool hasNext() const;
304
319 UBool next(UErrorCode &errorCode);
320
325 const UnicodeString &getString() const { return str_; }
330 int32_t getValue() const { return value_; }
331
332 private:
333 UBool truncateAndStop() {
334 pos_=NULL;
335 value_=-1; // no real value for str
336 return TRUE;
337 }
338
339 const UChar *branchNext(const UChar *pos, int32_t length, UErrorCode &errorCode);
340
341 const UChar *uchars_;
342 const UChar *pos_;
343 const UChar *initialPos_;
344 int32_t remainingMatchLength_;
345 int32_t initialRemainingMatchLength_;
346 UBool skipValue_; // Skip intermediate value which was already delivered.
347
348 UnicodeString str_;
349 int32_t maxLength_;
350 int32_t value_;
351
352 // The stack stores pairs of integers for backtracking to another
353 // outbound edge of a branch node.
354 // The first integer is an offset from uchars_.
355 // The second integer has the str_.length() from before the node in bits 15..0,
356 // and the remaining branch length in bits 31..16.
357 // (We could store the remaining branch length minus 1 in bits 30..16 and not use the sign bit,
358 // but the code looks more confusing that way.)
359 UVector32 *stack_;
360 };
361
362 private:
363 friend class UCharsTrieBuilder;
364
371 UCharsTrie(UChar *adoptUChars, const UChar *trieUChars)
372 : ownedArray_(adoptUChars), uchars_(trieUChars),
373 pos_(uchars_), remainingMatchLength_(-1) {}
374
375 // No assignment operator.
376 UCharsTrie &operator=(const UCharsTrie &other);
377
378 inline void stop() {
379 pos_=NULL;
380 }
381
382 // Reads a compact 32-bit integer.
383 // pos is already after the leadUnit, and the lead unit has bit 15 reset.
384 static inline int32_t readValue(const UChar *pos, int32_t leadUnit) {
385 int32_t value;
386 if(leadUnit<kMinTwoUnitValueLead) {
387 value=leadUnit;
388 } else if(leadUnit<kThreeUnitValueLead) {
389 value=((leadUnit-kMinTwoUnitValueLead)<<16)|*pos;
390 } else {
391 value=(pos[0]<<16)|pos[1];
392 }
393 return value;
394 }
395 static inline const UChar *skipValue(const UChar *pos, int32_t leadUnit) {
396 if(leadUnit>=kMinTwoUnitValueLead) {
397 if(leadUnit<kThreeUnitValueLead) {
398 ++pos;
399 } else {
400 pos+=2;
401 }
402 }
403 return pos;
404 }
405 static inline const UChar *skipValue(const UChar *pos) {
406 int32_t leadUnit=*pos++;
407 return skipValue(pos, leadUnit&0x7fff);
408 }
409
410 static inline int32_t readNodeValue(const UChar *pos, int32_t leadUnit) {
411 // U_ASSERT(kMinValueLead<=leadUnit && leadUnit<kValueIsFinal);
412 int32_t value;
413 if(leadUnit<kMinTwoUnitNodeValueLead) {
414 value=(leadUnit>>6)-1;
415 } else if(leadUnit<kThreeUnitNodeValueLead) {
416 value=(((leadUnit&0x7fc0)-kMinTwoUnitNodeValueLead)<<10)|*pos;
417 } else {
418 value=(pos[0]<<16)|pos[1];
419 }
420 return value;
421 }
422 static inline const UChar *skipNodeValue(const UChar *pos, int32_t leadUnit) {
423 // U_ASSERT(kMinValueLead<=leadUnit && leadUnit<kValueIsFinal);
424 if(leadUnit>=kMinTwoUnitNodeValueLead) {
425 if(leadUnit<kThreeUnitNodeValueLead) {
426 ++pos;
427 } else {
428 pos+=2;
429 }
430 }
431 return pos;
432 }
433
434 static inline const UChar *jumpByDelta(const UChar *pos) {
435 int32_t delta=*pos++;
436 if(delta>=kMinTwoUnitDeltaLead) {
437 if(delta==kThreeUnitDeltaLead) {
438 delta=(pos[0]<<16)|pos[1];
439 pos+=2;
440 } else {
441 delta=((delta-kMinTwoUnitDeltaLead)<<16)|*pos++;
442 }
443 }
444 return pos+delta;
445 }
446
447 static const UChar *skipDelta(const UChar *pos) {
448 int32_t delta=*pos++;
449 if(delta>=kMinTwoUnitDeltaLead) {
450 if(delta==kThreeUnitDeltaLead) {
451 pos+=2;
452 } else {
453 ++pos;
454 }
455 }
456 return pos;
457 }
458
459 static inline UStringTrieResult valueResult(int32_t node) {
460 return (UStringTrieResult)(USTRINGTRIE_INTERMEDIATE_VALUE-(node>>15));
461 }
462
463 // Handles a branch node for both next(uchar) and next(string).
464 UStringTrieResult branchNext(const UChar *pos, int32_t length, int32_t uchar);
465
466 // Requires remainingLength_<0.
467 UStringTrieResult nextImpl(const UChar *pos, int32_t uchar);
468
469 // Helper functions for hasUniqueValue().
470 // Recursively finds a unique value (or whether there is not a unique one)
471 // from a branch.
472 static const UChar *findUniqueValueFromBranch(const UChar *pos, int32_t length,
473 UBool haveUniqueValue, int32_t &uniqueValue);
474 // Recursively finds a unique value (or whether there is not a unique one)
475 // starting from a position on a node lead unit.
476 static UBool findUniqueValue(const UChar *pos, UBool haveUniqueValue, int32_t &uniqueValue);
477
478 // Helper functions for getNextUChars().
479 // getNextUChars() when pos is on a branch node.
480 static void getNextBranchUChars(const UChar *pos, int32_t length, Appendable &out);
481
482 // UCharsTrie data structure
483 //
484 // The trie consists of a series of UChar-serialized nodes for incremental
485 // Unicode string/UChar sequence matching. (UChar=16-bit unsigned integer)
486 // The root node is at the beginning of the trie data.
487 //
488 // Types of nodes are distinguished by their node lead unit ranges.
489 // After each node, except a final-value node, another node follows to
490 // encode match values or continue matching further units.
491 //
492 // Node types:
493 // - Final-value node: Stores a 32-bit integer in a compact, variable-length format.
494 // The value is for the string/UChar sequence so far.
495 // - Match node, optionally with an intermediate value in a different compact format.
496 // The value, if present, is for the string/UChar sequence so far.
497 //
498 // Aside from the value, which uses the node lead unit's high bits:
499 //
500 // - Linear-match node: Matches a number of units.
501 // - Branch node: Branches to other nodes according to the current input unit.
502 // The node unit is the length of the branch (number of units to select from)
503 // minus 1. It is followed by a sub-node:
504 // - If the length is at most kMaxBranchLinearSubNodeLength, then
505 // there are length-1 (key, value) pairs and then one more comparison unit.
506 // If one of the key units matches, then the value is either a final value for
507 // the string so far, or a "jump" delta to the next node.
508 // If the last unit matches, then matching continues with the next node.
509 // (Values have the same encoding as final-value nodes.)
510 // - If the length is greater than kMaxBranchLinearSubNodeLength, then
511 // there is one unit and one "jump" delta.
512 // If the input unit is less than the sub-node unit, then "jump" by delta to
513 // the next sub-node which will have a length of length/2.
514 // (The delta has its own compact encoding.)
515 // Otherwise, skip the "jump" delta to the next sub-node
516 // which will have a length of length-length/2.
517
518 // Match-node lead unit values, after masking off intermediate-value bits:
519
520 // 0000..002f: Branch node. If node!=0 then the length is node+1, otherwise
521 // the length is one more than the next unit.
522
523 // For a branch sub-node with at most this many entries, we drop down
524 // to a linear search.
525 static const int32_t kMaxBranchLinearSubNodeLength=5;
526
527 // 0030..003f: Linear-match node, match 1..16 units and continue reading the next node.
528 static const int32_t kMinLinearMatch=0x30;
529 static const int32_t kMaxLinearMatchLength=0x10;
530
531 // Match-node lead unit bits 14..6 for the optional intermediate value.
532 // If these bits are 0, then there is no intermediate value.
533 // Otherwise, see the *NodeValue* constants below.
534 static const int32_t kMinValueLead=kMinLinearMatch+kMaxLinearMatchLength; // 0x0040
535 static const int32_t kNodeTypeMask=kMinValueLead-1; // 0x003f
536
537 // A final-value node has bit 15 set.
538 static const int32_t kValueIsFinal=0x8000;
539
540 // Compact value: After testing and masking off bit 15, use the following thresholds.
541 static const int32_t kMaxOneUnitValue=0x3fff;
542
543 static const int32_t kMinTwoUnitValueLead=kMaxOneUnitValue+1; // 0x4000
544 static const int32_t kThreeUnitValueLead=0x7fff;
545
546 static const int32_t kMaxTwoUnitValue=((kThreeUnitValueLead-kMinTwoUnitValueLead)<<16)-1; // 0x3ffeffff
547
548 // Compact intermediate-value integer, lead unit shared with a branch or linear-match node.
549 static const int32_t kMaxOneUnitNodeValue=0xff;
550 static const int32_t kMinTwoUnitNodeValueLead=kMinValueLead+((kMaxOneUnitNodeValue+1)<<6); // 0x4040
551 static const int32_t kThreeUnitNodeValueLead=0x7fc0;
552
553 static const int32_t kMaxTwoUnitNodeValue=
554 ((kThreeUnitNodeValueLead-kMinTwoUnitNodeValueLead)<<10)-1; // 0xfdffff
555
556 // Compact delta integers.
557 static const int32_t kMaxOneUnitDelta=0xfbff;
558 static const int32_t kMinTwoUnitDeltaLead=kMaxOneUnitDelta+1; // 0xfc00
559 static const int32_t kThreeUnitDeltaLead=0xffff;
560
561 static const int32_t kMaxTwoUnitDelta=((kThreeUnitDeltaLead-kMinTwoUnitDeltaLead)<<16)-1; // 0x03feffff
562
563 UChar *ownedArray_;
564
565 // Fixed value referencing the UCharsTrie words.
566 const UChar *uchars_;
567
568 // Iterator variables.
569
570 // Pointer to next trie unit to read. NULL if no more matches.
571 const UChar *pos_;
572 // Remaining length of a linear-match node, minus 1. Negative if not in such a node.
573 int32_t remainingMatchLength_;
574 };
575
576 U_NAMESPACE_END
577
578 #endif // __UCHARSTRIE_H__
icu::UCharsTrie::resetToState
UCharsTrie & resetToState(const State &state)
Resets this trie to the saved state.
Definition: ucharstrie.h:141
icu::UCharsTrie::hasUniqueValue
UBool hasUniqueValue(int32_t &uniqueValue) const
Determines whether all strings reachable from the current state map to the same value.
Definition: ucharstrie.h:239
unistr.h
C++ API: Unicode String.
UStringTrieResult
UStringTrieResult
Return values for BytesTrie::next(), UCharsTrie::next() and similar methods.
Definition: ustringtrie.h:35
icu::UCharsTrie::UCharsTrie
UCharsTrie(const UCharsTrie &other)
Copy constructor, copies the other trie reader object and its state, but not the UChar array which wi...
Definition: ucharstrie.h:82
icu::UCharsTrie::getValue
int32_t getValue() const
Returns a matching string&#39;s value if called immediately after current()/first()/next() returned USTRI...
Definition: ucharstrie.h:222
U_NAMESPACE_BEGIN
#define U_NAMESPACE_BEGIN
This is used to begin a declaration of a public ICU C++ API.
Definition: uversion.h:131
icu::UCharsTrie::Iterator::getValue
int32_t getValue() const
Definition: ucharstrie.h:330
icu::UCharsTrie::reset
UCharsTrie & reset()
Resets this trie to its initial state.
Definition: ucharstrie.h:91
icu::UCharsTrie::Iterator
Iterator for all of the (string, value) pairs in a UCharsTrie.
Definition: ucharstrie.h:258
UChar32
int32_t UChar32
Define UChar32 as a type for single Unicode code points.
Definition: umachine.h:357
NULL
#define NULL
Define NULL if necessary, to 0 for C++ and to ((void *)0) for C.
Definition: utypes.h:188
icu::UCharsTrieBuilder
Builder class for UCharsTrie.
Definition: ucharstriebuilder.h:40
TRUE
#define TRUE
The TRUE value of a UBool.
Definition: umachine.h:263
uobject.h
C++ API: Common ICU base class UObject.
UChar
uint16_t UChar
Define UChar to be UCHAR_TYPE, if that is #defined (for example, to char16_t), or wchar_t if that is ...
Definition: umachine.h:337
U_NAMESPACE_END
#define U_NAMESPACE_END
This is used to end a declaration of a public ICU C++ API.
Definition: uversion.h:132
icu::UCharsTrie::State::State
State()
Constructs an empty State.
Definition: ucharstrie.h:108
UErrorCode
UErrorCode
Error code to replace exception handling, so that the code is compatible with all C++ compilers...
Definition: utypes.h:396
icu::UCharsTrie::State
UCharsTrie state object, for saving a trie&#39;s current state and resetting the trie back to this state ...
Definition: ucharstrie.h:102
ustringtrie.h
C API: Helper definitions for dictionary trie APIs.
utypes.h
Basic definitions for ICU, for both C and C++ APIs.
FALSE
#define FALSE
The FALSE value of a UBool.
Definition: umachine.h:267
U_COMMON_API
#define U_COMMON_API
Set to export library symbols from inside the common library, and to import them from outside...
Definition: utypes.h:359
icu::UnicodeString
UnicodeString is a string class that stores Unicode characters directly and provides similar function...
Definition: unistr.h:295
USTRINGTRIE_INTERMEDIATE_VALUE
The input unit(s) continued a matching string and there is a value for the string so far...
Definition: ustringtrie.h:66
icu::UCharsTrie::first
UStringTrieResult first(int32_t uchar)
Traverses the trie from the initial state for this input UChar.
Definition: ucharstrie.h:164
icu::UCharsTrie::UCharsTrie
UCharsTrie(const UChar *trieUChars)
Constructs a UCharsTrie reader instance.
Definition: ucharstrie.h:66
icu::UCharsTrie::Iterator::getString
const UnicodeString & getString() const
Definition: ucharstrie.h:325
icu::UMemory
UMemory is the common ICU base class.
Definition: uobject.h:112
icu::UCharsTrie
Light-weight, non-const reader class for a UCharsTrie.
Definition: ucharstrie.h:50
icu::UCharsTrie::saveState
const UCharsTrie & saveState(State &state) const
Saves the state of this trie.
Definition: ucharstrie.h:124
UBool
int8_t UBool
The ICU boolean type.
Definition: umachine.h:259
icu::Appendable
Base class for objects to which Unicode characters and strings can be appended.
Definition: appendable.h:51