tor-browser

rbbi.h (32487B)

---

// © 2016 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
/*
***************************************************************************
*   Copyright (C) 1999-2016 International Business Machines Corporation   *
*   and others. All rights reserved.                                      *
***************************************************************************

**********************************************************************
*   Date        Name        Description
*   10/22/99    alan        Creation.
*   11/11/99    rgillam     Complete port from Java.
**********************************************************************
*/

#ifndef RBBI_H
#define RBBI_H

#include "unicode/utypes.h"

#if U_SHOW_CPLUSPLUS_API

/**
* \file
* \brief C++ API: Rule Based Break Iterator
*/

#if !UCONFIG_NO_BREAK_ITERATION

#include "unicode/brkiter.h"
#include "unicode/udata.h"
#include "unicode/parseerr.h"
#include "unicode/schriter.h"

struct UCPTrie;

U_NAMESPACE_BEGIN

/** @internal */
class  LanguageBreakEngine;
struct RBBIDataHeader;
class  RBBIDataWrapper;
class  UnhandledEngine;
class  UStack;


#ifndef U_HIDE_INTERNAL_API
/**
* The ExternalBreakEngine class define an abstract interface for the host environment
* to provide a low level facility to break text for unicode text in script that the text boundary
* cannot be handled by upper level rule based logic, for example, for Chinese and Japanese
* word breaking, Thai, Khmer, Burmese, Lao and other Southeast Asian scripts.
* The host environment implement one or more subclass of ExternalBreakEngine and
* register them in the initialization time by calling
* RuleBasedBreakIterator::registerExternalBreakEngine(). ICU adopt and own the engine and will
* delete the registered external engine in proper time during the clean up
* event.
* @internal ICU 74 technology preview
*/
class ExternalBreakEngine : public UObject {
 public:
   /**
    * destructor
    * @internal ICU 74 technology preview
    */
   virtual ~ExternalBreakEngine() {}

   /**
    * <p>Indicate whether this engine handles a particular character when
    * the RuleBasedBreakIterator is used for a particular locale. This method is used
    * by the RuleBasedBreakIterator to find a break engine.</p>
    * @param c A character which begins a run that the engine might handle.
    * @param locale    The locale.
    * @return true if this engine handles the particular character for that locale.
    * @internal ICU 74 technology preview
    */
   virtual bool isFor(UChar32 c, const char* locale) const = 0;

   /**
    * <p>Indicate whether this engine handles a particular character.This method is
    * used by the RuleBasedBreakIterator after it already find a break engine to see which
    * characters after the first one can be handled by this break engine.</p>
    * @param c A character that the engine might handle.
    * @return true if this engine handles the particular character.
    * @internal ICU 74 technology preview
    */
   virtual bool handles(UChar32 c) const = 0;

   /**
    * <p>Divide up a range of text handled by this break engine.</p>
    *
    * @param text A UText representing the text
    * @param start The start of the range of known characters
    * @param end The end of the range of known characters
    * @param foundBreaks Output of C array of int32_t break positions, or
    * nullptr
    * @param foundBreaksCapacity The capacity of foundBreaks
    * @param status Information on any errors encountered.
    * @return The number of breaks found
    * @internal ICU 74 technology preview
    */
    virtual int32_t fillBreaks(UText* text,  int32_t start, int32_t end,
                              int32_t* foundBreaks, int32_t foundBreaksCapacity,
                              UErrorCode& status) const = 0;
};
#endif  /* U_HIDE_INTERNAL_API */


/**
*
* A subclass of BreakIterator whose behavior is specified using a list of rules.
* <p>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</p>
*
* <p>See the ICU User Guide for information on Break Iterator Rules.</p>
*
* <p>This class is not intended to be subclassed.</p>
*/
class U_COMMON_API RuleBasedBreakIterator /*final*/ : public BreakIterator {

private:
   /**
    * The UText through which this BreakIterator accesses the text
    */
   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.
    */
   UStack              *fLanguageBreakEngines = nullptr;

   /**
    *
    * If present, the special LanguageBreakEngine used for handling
    * characters that are in the dictionary set, but not handled by any
    * LanguageBreakEngine.
    */
   UnhandledEngine     *fUnhandledBreakEngine = nullptr;

   /**
    * Counter for the number of characters encountered with the "dictionary"
    *   flag set.
    */
   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.
    */
   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
    */
   RuleBasedBreakIterator(UDataMemory* image, UBool isPhraseBreaking, UErrorCode &status);

   friend class RBBIRuleBuilder;
   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.
    */
   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() 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() const;

   //=======================================================================
   // BreakIterator overrides
   //=======================================================================

   /**
    * <p>
    * 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.
    * </p>
    * <p>
    * 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.
    * </p>
    * <p>
    * 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.
    * </p>
    *
    * TODO:  deprecate this function?
    *
    * @return An iterator over the text being analyzed.
    * @stable ICU 2.0
    */
   virtual CharacterIterator& getText() 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() 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() 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() 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() 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() 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.
    * <p>
    * 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.
    * <p>
    * <code>getRuleStatus()</code> can be called after obtaining a boundary
    * position from <code>next()</code>, <code>previous()</code>, or
    * any other break iterator functions that returns a boundary position.
    * <p>
    * Note that <code>getRuleStatus()</code> returns the value corresponding to
    * <code>current()</code> index even after <code>next()</code> has returned DONE.
    * <p>
    * When creating custom break rules, one is free to define whatever
    * status values may be convenient for the application.
    * <p>
    * @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.
   * <p>
   * 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() 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();

#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.
    */
   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.
    */
   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<typename RowType, PTrieFunc trieFunc>
   int32_t handleSafePrevious(int32_t fromPosition);

   template<typename RowType, PTrieFunc trieFunc>
   int32_t handleNext();


   /**
    * This function returns the appropriate LanguageBreakEngine for a
    * given character c.
    * @param c         A character in the dictionary set
    * @param locale    The locale.
    */
   const LanguageBreakEngine *getLanguageBreakEngine(UChar32 c, const char* locale);

 public:
#ifndef U_HIDE_INTERNAL_API
   /**
    *   Debugging function only.
    *   @internal
    */
    void dumpCache();

   /**
    * Debugging function only.
    * @internal
    */
   void dumpTables();
#endif  /* U_HIDE_INTERNAL_API */

#ifndef U_HIDE_INTERNAL_API
   /**
    * Register a new external break engine. The external break engine will be adopted.
    * Because ICU may choose to cache break engine internally, this must
    * be called at application startup, prior to any calls to
    * object methods of RuleBasedBreakIterator to avoid undefined behavior.
    * @param toAdopt the ExternalBreakEngine instance to be adopted
    * @param status the in/out status code, no special meanings are assigned
    * @internal ICU 74 technology preview
    */
   static void U_EXPORT2 registerExternalBreakEngine(
                 ExternalBreakEngine* toAdopt, UErrorCode& status);
#endif  /* U_HIDE_INTERNAL_API */

};


U_NAMESPACE_END

#endif /* #if !UCONFIG_NO_BREAK_ITERATION */

#endif /* U_SHOW_CPLUSPLUS_API */

#endif