Instances of this class are most commonly created by the factory methods of * BreakIterator::createWordInstance(), BreakIterator::createLineInstance(), etc., * and then used via the abstract API in class BreakIterator
* *See the ICU User Guide for information on Break Iterator Rules.
* *This class is not intended to be subclassed.
*/ class U_COMMON_API RuleBasedBreakIterator /*final*/ : public BreakIterator { private: /** * The UText through which this BreakIterator accesses the text * @internal (private) */ UText fText = UTEXT_INITIALIZER; #ifndef U_HIDE_INTERNAL_API public: #endif /* U_HIDE_INTERNAL_API */ /** * The rule data for this BreakIterator instance. * Not for general use; Public only for testing purposes. * @internal */ RBBIDataWrapper *fData = nullptr; private: /** * The saved error code associated with this break iterator. * This is the value to be returned by copyErrorTo(). */ UErrorCode fErrorCode = U_ZERO_ERROR; /** * The current position of the iterator. Pinned, 0 < fPosition <= text.length. * Never has the value UBRK_DONE (-1). */ int32_t fPosition = 0; /** * TODO: */ int32_t fRuleStatusIndex = 0; /** * Cache of previously determined boundary positions. */ class BreakCache; BreakCache *fBreakCache = nullptr; /** * Cache of boundary positions within a region of text that has been * sub-divided by dictionary based breaking. */ class DictionaryCache; DictionaryCache *fDictionaryCache = nullptr; /** * * If present, UStack of LanguageBreakEngine objects that might handle * dictionary characters. Searched from top to bottom to find an object to * handle a given character. * @internal (private) */ UStack *fLanguageBreakEngines = nullptr; /** * * If present, the special LanguageBreakEngine used for handling * characters that are in the dictionary set, but not handled by any * LanguageBreakEngine. * @internal (private) */ UnhandledEngine *fUnhandledBreakEngine = nullptr; /** * Counter for the number of characters encountered with the "dictionary" * flag set. * @internal (private) */ uint32_t fDictionaryCharCount = 0; /** * A character iterator that refers to the same text as the UText, above. * Only included for compatibility with old API, which was based on CharacterIterators. * Value may be adopted from outside, or one of fSCharIter or fDCharIter, below. */ CharacterIterator *fCharIter = &fSCharIter; /** * When the input text is provided by a UnicodeString, this will point to * a characterIterator that wraps that data. Needed only for the * implementation of getText(), a backwards compatibility issue. */ UCharCharacterIterator fSCharIter {u"", 0}; /** * True when iteration has run off the end, and iterator functions should return UBRK_DONE. */ bool fDone = false; /** * Array of look-ahead tentative results. */ int32_t *fLookAheadMatches = nullptr; /** * A flag to indicate if phrase based breaking is enabled. */ UBool fIsPhraseBreaking = false; //======================================================================= // constructors //======================================================================= /** * Constructor from a flattened set of RBBI data in malloced memory. * RulesBasedBreakIterators built from a custom set of rules * are created via this constructor; the rules are compiled * into memory, then the break iterator is constructed here. * * The break iterator adopts the memory, and will * free it when done. * @internal (private) */ RuleBasedBreakIterator(RBBIDataHeader* data, UErrorCode &status); /** * This constructor uses the udata interface to create a BreakIterator * whose internal tables live in a memory-mapped file. "image" is an * ICU UDataMemory handle for the pre-compiled break iterator tables. * @param image handle to the memory image for the break iterator data. * Ownership of the UDataMemory handle passes to the Break Iterator, * which will be responsible for closing it when it is no longer needed. * @param status Information on any errors encountered. * @param isPhraseBreaking true if phrase based breaking is required, otherwise false. * @see udata_open * @see #getBinaryRules * @internal (private) */ RuleBasedBreakIterator(UDataMemory* image, UBool isPhraseBreaking, UErrorCode &status); /** @internal */ friend class RBBIRuleBuilder; /** @internal */ friend class BreakIterator; /** * Default constructor with an error code parameter. * Aside from error handling, otherwise identical to the default constructor. * Internally, handles common initialization for other constructors. * @internal (private) */ RuleBasedBreakIterator(UErrorCode *status); public: /** Default constructor. Creates an empty shell of an iterator, with no * rules or text to iterate over. Object can subsequently be assigned to, * but is otherwise unusable. * @stable ICU 2.2 */ RuleBasedBreakIterator(); /** * Copy constructor. Will produce a break iterator with the same behavior, * and which iterates over the same text, as the one passed in. * @param that The RuleBasedBreakIterator passed to be copied * @stable ICU 2.0 */ RuleBasedBreakIterator(const RuleBasedBreakIterator& that); /** * Construct a RuleBasedBreakIterator from a set of rules supplied as a string. * @param rules The break rules to be used. * @param parseError In the event of a syntax error in the rules, provides the location * within the rules of the problem. * @param status Information on any errors encountered. * @stable ICU 2.2 */ RuleBasedBreakIterator( const UnicodeString &rules, UParseError &parseError, UErrorCode &status); /** * Construct a RuleBasedBreakIterator from a set of precompiled binary rules. * Binary rules are obtained from RulesBasedBreakIterator::getBinaryRules(). * Construction of a break iterator in this way is substantially faster than * construction from source rules. * * Ownership of the storage containing the compiled rules remains with the * caller of this function. The compiled rules must not be modified or * deleted during the life of the break iterator. * * The compiled rules are not compatible across different major versions of ICU. * The compiled rules are compatible only between machines with the same * byte ordering (little or big endian) and the same base character set family * (ASCII or EBCDIC). * * @see #getBinaryRules * @param compiledRules A pointer to the compiled break rules to be used. * @param ruleLength The length of the compiled break rules, in bytes. This * corresponds to the length value produced by getBinaryRules(). * @param status Information on any errors encountered, including invalid * binary rules. * @stable ICU 4.8 */ RuleBasedBreakIterator(const uint8_t *compiledRules, uint32_t ruleLength, UErrorCode &status); /** * This constructor uses the udata interface to create a BreakIterator * whose internal tables live in a memory-mapped file. "image" is an * ICU UDataMemory handle for the pre-compiled break iterator tables. * @param image handle to the memory image for the break iterator data. * Ownership of the UDataMemory handle passes to the Break Iterator, * which will be responsible for closing it when it is no longer needed. * @param status Information on any errors encountered. * @see udata_open * @see #getBinaryRules * @stable ICU 2.8 */ RuleBasedBreakIterator(UDataMemory* image, UErrorCode &status); /** * Destructor * @stable ICU 2.0 */ virtual ~RuleBasedBreakIterator(); /** * Assignment operator. Sets this iterator to have the same behavior, * and iterate over the same text, as the one passed in. * @param that The RuleBasedBreakItertor passed in * @return the newly created RuleBasedBreakIterator * @stable ICU 2.0 */ RuleBasedBreakIterator& operator=(const RuleBasedBreakIterator& that); /** * Equality operator. Returns true if both BreakIterators are of the * same class, have the same behavior, and iterate over the same text. * @param that The BreakIterator to be compared for equality * @return true if both BreakIterators are of the * same class, have the same behavior, and iterate over the same text. * @stable ICU 2.0 */ virtual bool operator==(const BreakIterator& that) const override; /** * Not-equal operator. If operator== returns true, this returns false, * and vice versa. * @param that The BreakIterator to be compared for inequality * @return true if both BreakIterators are not same. * @stable ICU 2.0 */ inline bool operator!=(const BreakIterator& that) const { return !operator==(that); } /** * Returns a newly-constructed RuleBasedBreakIterator with the same * behavior, and iterating over the same text, as this one. * Differs from the copy constructor in that it is polymorphic, and * will correctly clone (copy) a derived class. * clone() is thread safe. Multiple threads may simultaneously * clone the same source break iterator. * @return a newly-constructed RuleBasedBreakIterator * @stable ICU 2.0 */ virtual RuleBasedBreakIterator* clone() const override; /** * Compute a hash code for this BreakIterator * @return A hash code * @stable ICU 2.0 */ virtual int32_t hashCode(void) const; /** * Returns the description used to create this iterator * @return the description used to create this iterator * @stable ICU 2.0 */ virtual const UnicodeString& getRules(void) const; //======================================================================= // BreakIterator overrides //======================================================================= /** ** Return a CharacterIterator over the text being analyzed. * The returned character iterator is owned by the break iterator, and must * not be deleted by the caller. Repeated calls to this function may * return the same CharacterIterator. *
** The returned character iterator must not be used concurrently with * the break iterator. If concurrent operation is needed, clone the * returned character iterator first and operate on the clone. *
** When the break iterator is operating on text supplied via a UText, * this function will fail, returning a CharacterIterator containing no text. * The function getUText() provides similar functionality, * is reliable, and is more efficient. *
* * TODO: deprecate this function? * * @return An iterator over the text being analyzed. * @stable ICU 2.0 */ virtual CharacterIterator& getText(void) const override; /** * Get a UText for the text being analyzed. * The returned UText is a shallow clone of the UText used internally * by the break iterator implementation. It can safely be used to * access the text without impacting any break iterator operations, * but the underlying text itself must not be altered. * * @param fillIn A UText to be filled in. If nullptr, a new UText will be * allocated to hold the result. * @param status receives any error codes. * @return The current UText for this break iterator. If an input * UText was provided, it will always be returned. * @stable ICU 3.4 */ virtual UText *getUText(UText *fillIn, UErrorCode &status) const override; /** * Set the iterator to analyze a new piece of text. This function resets * the current iteration position to the beginning of the text. * @param newText An iterator over the text to analyze. The BreakIterator * takes ownership of the character iterator. The caller MUST NOT delete it! * @stable ICU 2.0 */ virtual void adoptText(CharacterIterator* newText) override; /** * Set the iterator to analyze a new piece of text. This function resets * the current iteration position to the beginning of the text. * * The BreakIterator will retain a reference to the supplied string. * The caller must not modify or delete the text while the BreakIterator * retains the reference. * * @param newText The text to analyze. * @stable ICU 2.0 */ virtual void setText(const UnicodeString& newText) override; /** * Reset the break iterator to operate over the text represented by * the UText. The iterator position is reset to the start. * * This function makes a shallow clone of the supplied UText. This means * that the caller is free to immediately close or otherwise reuse the * Utext that was passed as a parameter, but that the underlying text itself * must not be altered while being referenced by the break iterator. * * @param text The UText used to change the text. * @param status Receives any error codes. * @stable ICU 3.4 */ virtual void setText(UText *text, UErrorCode &status) override; /** * Sets the current iteration position to the beginning of the text, position zero. * @return The offset of the beginning of the text, zero. * @stable ICU 2.0 */ virtual int32_t first(void) override; /** * Sets the current iteration position to the end of the text. * @return The text's past-the-end offset. * @stable ICU 2.0 */ virtual int32_t last(void) override; /** * Advances the iterator either forward or backward the specified number of steps. * Negative values move backward, and positive values move forward. This is * equivalent to repeatedly calling next() or previous(). * @param n The number of steps to move. The sign indicates the direction * (negative is backwards, and positive is forwards). * @return The character offset of the boundary position n boundaries away from * the current one. * @stable ICU 2.0 */ virtual int32_t next(int32_t n) override; /** * Advances the iterator to the next boundary position. * @return The position of the first boundary after this one. * @stable ICU 2.0 */ virtual int32_t next(void) override; /** * Moves the iterator backwards, to the last boundary preceding this one. * @return The position of the last boundary position preceding this one. * @stable ICU 2.0 */ virtual int32_t previous(void) override; /** * Sets the iterator to refer to the first boundary position following * the specified position. * @param offset The position from which to begin searching for a break position. * @return The position of the first break after the current position. * @stable ICU 2.0 */ virtual int32_t following(int32_t offset) override; /** * Sets the iterator to refer to the last boundary position before the * specified position. * @param offset The position to begin searching for a break from. * @return The position of the last boundary before the starting position. * @stable ICU 2.0 */ virtual int32_t preceding(int32_t offset) override; /** * Returns true if the specified position is a boundary position. As a side * effect, leaves the iterator pointing to the first boundary position at * or after "offset". * @param offset the offset to check. * @return True if "offset" is a boundary position. * @stable ICU 2.0 */ virtual UBool isBoundary(int32_t offset) override; /** * Returns the current iteration position. Note that UBRK_DONE is never * returned from this function; if iteration has run to the end of a * string, current() will return the length of the string while * next() will return UBRK_DONE). * @return The current iteration position. * @stable ICU 2.0 */ virtual int32_t current(void) const override; /** * Return the status tag from the break rule that determined the boundary at * the current iteration position. For break rules that do not specify a * status, a default value of 0 is returned. If more than one break rule * would cause a boundary to be located at some position in the text, * the numerically largest of the applicable status values is returned. ** Of the standard types of ICU break iterators, only word break and * line break provide status values. The values are defined in * the header file ubrk.h. For Word breaks, the status allows distinguishing between words * that contain alphabetic letters, "words" that appear to be numbers, * punctuation and spaces, words containing ideographic characters, and * more. For Line Break, the status distinguishes between hard (mandatory) breaks * and soft (potential) break positions. *
* getRuleStatus() can be called after obtaining a boundary
* position from next(), previous(), or
* any other break iterator functions that returns a boundary position.
*
* Note that getRuleStatus() returns the value corresponding to
* current() index even after next() has returned DONE.
*
* When creating custom break rules, one is free to define whatever * status values may be convenient for the application. *
* @return the status from the break rule that determined the boundary * at the current iteration position. * * @see UWordBreak * @stable ICU 2.2 */ virtual int32_t getRuleStatus() const override; /** * Get the status (tag) values from the break rule(s) that determined the boundary * at the current iteration position. *
* The returned status value(s) are stored into an array provided by the caller.
* The values are stored in sorted (ascending) order.
* If the capacity of the output array is insufficient to hold the data,
* the output will be truncated to the available length, and a
* U_BUFFER_OVERFLOW_ERROR will be signaled.
*
* @param fillInVec an array to be filled in with the status values.
* @param capacity the length of the supplied vector. A length of zero causes
* the function to return the number of status values, in the
* normal way, without attempting to store any values.
* @param status receives error codes.
* @return The number of rule status values from the rules that determined
* the boundary at the current iteration position.
* In the event of a U_BUFFER_OVERFLOW_ERROR, the return value
* is the total number of status values that were available,
* not the reduced number that were actually returned.
* @see getRuleStatus
* @stable ICU 3.0
*/
virtual int32_t getRuleStatusVec(int32_t *fillInVec, int32_t capacity, UErrorCode &status) override;
/**
* Returns a unique class ID POLYMORPHICALLY. Pure virtual override.
* This method is to implement a simple version of RTTI, since not all
* C++ compilers support genuine RTTI. Polymorphic operator==() and
* clone() methods call this method.
*
* @return The class ID for this object. All objects of a
* given class have the same class ID. Objects of
* other classes have different class IDs.
* @stable ICU 2.0
*/
virtual UClassID getDynamicClassID(void) const override;
/**
* Returns the class ID for this class. This is useful only for
* comparing to a return value from getDynamicClassID(). For example:
*
* Base* polymorphic_pointer = createPolymorphicObject();
* if (polymorphic_pointer->getDynamicClassID() ==
* Derived::getStaticClassID()) ...
*
* @return The class ID for all objects of this class.
* @stable ICU 2.0
*/
static UClassID U_EXPORT2 getStaticClassID(void);
#ifndef U_FORCE_HIDE_DEPRECATED_API
/**
* Deprecated functionality. Use clone() instead.
*
* Create a clone (copy) of this break iterator in memory provided
* by the caller. The idea is to increase performance by avoiding
* a storage allocation. Use of this function is NOT RECOMMENDED.
* Performance gains are minimal, and correct buffer management is
* tricky. Use clone() instead.
*
* @param stackBuffer The pointer to the memory into which the cloned object
* should be placed. If nullptr, allocate heap memory
* for the cloned object.
* @param BufferSize The size of the buffer. If zero, return the required
* buffer size, but do not clone the object. If the
* size was too small (but not zero), allocate heap
* storage for the cloned object.
*
* @param status Error status. U_SAFECLONE_ALLOCATED_WARNING will be
* returned if the provided buffer was too small, and
* the clone was therefore put on the heap.
*
* @return Pointer to the clone object. This may differ from the stackBuffer
* address if the byte alignment of the stack buffer was not suitable
* or if the stackBuffer was too small to hold the clone.
* @deprecated ICU 52. Use clone() instead.
*/
virtual RuleBasedBreakIterator *createBufferClone(void *stackBuffer,
int32_t &BufferSize,
UErrorCode &status) override;
#endif // U_FORCE_HIDE_DEPRECATED_API
/**
* Return the binary form of compiled break rules,
* which can then be used to create a new break iterator at some
* time in the future. Creating a break iterator from pre-compiled rules
* is much faster than building one from the source form of the
* break rules.
*
* The binary data can only be used with the same version of ICU
* and on the same platform type (processor endian-ness)
*
* @param length Returns the length of the binary data. (Out parameter.)
*
* @return A pointer to the binary (compiled) rule data. The storage
* belongs to the RulesBasedBreakIterator object, not the
* caller, and must not be modified or deleted.
* @stable ICU 4.8
*/
virtual const uint8_t *getBinaryRules(uint32_t &length);
/**
* Set the subject text string upon which the break iterator is operating
* without changing any other aspect of the matching state.
* The new and previous text strings must have the same content.
*
* This function is intended for use in environments where ICU is operating on
* strings that may move around in memory. It provides a mechanism for notifying
* ICU that the string has been relocated, and providing a new UText to access the
* string in its new position.
*
* Note that the break iterator implementation never copies the underlying text
* of a string being processed, but always operates directly on the original text
* provided by the user. Refreshing simply drops the references to the old text
* and replaces them with references to the new.
*
* Caution: this function is normally used only by very specialized,
* system-level code. One example use case is with garbage collection that moves
* the text in memory.
*
* @param input The new (moved) text string.
* @param status Receives errors detected by this function.
* @return *this
*
* @stable ICU 49
*/
virtual RuleBasedBreakIterator &refreshInputText(UText *input, UErrorCode &status) override;
private:
//=======================================================================
// implementation
//=======================================================================
/**
* Iterate backwards from an arbitrary position in the input text using the
* synthesized Safe Reverse rules.
* This locates a "Safe Position" from which the forward break rules
* will operate correctly. A Safe Position is not necessarily a boundary itself.
*
* @param fromPosition the position in the input text to begin the iteration.
* @internal (private)
*/
int32_t handleSafePrevious(int32_t fromPosition);
/**
* Find a rule-based boundary by running the state machine.
* Input
* fPosition, the position in the text to begin from.
* Output
* fPosition: the boundary following the starting position.
* fDictionaryCharCount the number of dictionary characters encountered.
* If > 0, the segment will be further subdivided
* fRuleStatusIndex Info from the state table indicating which rules caused the boundary.
*
* @internal (private)
*/
int32_t handleNext();
/*
* Templatized version of handleNext() and handleSafePrevious().
*
* There will be exactly four instantiations, two each for 8 and 16 bit tables,
* two each for 8 and 16 bit trie.
* Having separate instantiations for the table types keeps conditional tests of
* the table type out of the inner loops, at the expense of replicated code.
*
* The template parameter for the Trie access function is a value, not a type.
* Doing it this way, the compiler will inline the Trie function in the
* expanded functions. (Both the 8 and 16 bit access functions have the same type
* signature)
*/
typedef uint16_t (*PTrieFunc)(const UCPTrie *, UChar32);
template