Check in the pristine copy of ICU 4.6...

icu46/source/common/unicode/rbbi.h

+/*
+***************************************************************************
+*   Copyright (C) 1999-2008 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"
+
+/**
+ * \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"
+#include "unicode/uchriter.h"
+
+
+struct UTrie;
+
+U_NAMESPACE_BEGIN
+
+/** @internal */
+struct RBBIDataHeader;
+class  RuleBasedBreakIteratorTables;
+class  BreakIterator;
+class  RBBIDataWrapper;
+class  UStack;
+class  LanguageBreakEngine;
+class  UnhandledEngine;
+struct RBBIStateTable;
+
+
+
+
+/**
+ *
+ * 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.  (Class DictionaryBasedBreakIterator
+ *    is a subclass, but that relationship is effectively internal to the ICU
+ *    implementation.  The subclassing interface to RulesBasedBreakIterator is
+ *    not part of the ICU API, and may not remain stable.</p>
+ *
+ */
+class U_COMMON_API RuleBasedBreakIterator : public BreakIterator {
+
+protected:
+    /**
+     * The UText through which this BreakIterator accesses the text
+     * @internal
+     */
+    UText  *fText;
+
+    /**
+     *   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;
+
+    /**
+     *   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.
+     */
+    StringCharacterIterator *fSCharIter;
+
+    /**
+     *  When the input text is provided by a UText, this
+     *    dummy CharacterIterator over an empty string will
+     *    be returned from getText()
+     */
+    UCharCharacterIterator *fDCharIter;
+
+    /**
+     * The rule data for this BreakIterator instance
+     * @internal
+     */
+    RBBIDataWrapper    *fData;
+
+    /** Index of the Rule {tag} values for the most recent match.
+     *  @internal
+    */
+    int32_t             fLastRuleStatusIndex;
+
+    /**
+     * Rule tag value valid flag.
+     * Some iterator operations don't intrinsically set the correct tag value.
+     * This flag lets us lazily compute the value if we are ever asked for it.
+     * @internal
+     */
+    UBool               fLastStatusIndexValid;
+
+    /**
+     * Counter for the number of characters encountered with the "dictionary"
+     *   flag set.
+     * @internal
+     */
+    uint32_t            fDictionaryCharCount;
+
+    /**
+     * When a range of characters is divided up using the dictionary, the break
+     * positions that are discovered are stored here, preventing us from having
+     * to use either the dictionary or the state table again until the iterator
+     * leaves this range of text. Has the most impact for line breaking.
+     * @internal
+     */
+    int32_t*            fCachedBreakPositions;
+
+    /**
+     * The number of elements in fCachedBreakPositions
+     * @internal
+     */
+    int32_t             fNumCachedBreakPositions;
+
+    /**
+     * if fCachedBreakPositions is not null, this indicates which item in the
+     * cache the current iteration position refers to
+     * @internal
+     */
+    int32_t             fPositionInCache;
+    
+    /**
+     *
+     * 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
+     */
+    UStack              *fLanguageBreakEngines;
+    
+    /**
+     *
+     * If present, the special LanguageBreakEngine used for handling
+     * characters that are in the dictionary set, but not handled by any
+     * LangugageBreakEngine.
+     * @internal
+     */
+    UnhandledEngine     *fUnhandledBreakEngine;
+    
+    /**
+     *
+     * The type of the break iterator, or -1 if it has not been set.
+     * @internal
+     */
+    int32_t             fBreakType;
+    
+protected:
+    //=======================================================================
+    // constructors
+    //=======================================================================
+
+    /**
+     * Constant to be used in the constructor
+     * RuleBasedBreakIterator(RBBIDataHeader*, EDontAdopt, UErrorCode &);
+     * which does not adopt the memory indicated by the RBBIDataHeader*
+     * parameter.
+     *
+     * @internal
+     */
+    enum EDontAdopt {
+        kDontAdopt
+    };
+
+    /**
+     * 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
+     */
+    RuleBasedBreakIterator(RBBIDataHeader* data, UErrorCode &status);
+
+    /**
+     * Constructor from a flattened set of RBBI data in memory which need not
+     *             be malloced (e.g. it may be a memory-mapped file, etc.).
+     *
+     *             This version does not adopt the memory, and does not
+     *             free it when done.
+     * @internal
+     */
+    RuleBasedBreakIterator(const RBBIDataHeader* data, enum EDontAdopt dontAdopt, UErrorCode &status);
+
+
+    friend class RBBIRuleBuilder;
+    /** @internal */
+    friend class BreakIterator;
+
+
+
+public:
+
+    /** Default constructor.  Creates an empty shell of an iterator, with no
+     *  rules or text to iterate over.   Object can subsequently be assigned to.
+     *  @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);
+
+
+    /**
+     * 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 UBool operator==(const BreakIterator& that) const;
+
+    /**
+     * 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
+     */
+    UBool operator!=(const BreakIterator& that) const;
+
+    /**
+     * 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 simultaeneously
+     * clone the same source break iterator.
+     * @return a newly-constructed RuleBasedBreakIterator
+     * @stable ICU 2.0
+     */
+    virtual BreakIterator* clone() const;
+
+    /**
+     * 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
+    //=======================================================================
+
+    /**
+     * <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.  Lacking any way to signal failures, it
+     * returns an 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(void) const;
+
+
+    /**
+      *  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 NULL, 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;
+
+    /**
+     * 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);
+
+    /**
+     * 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 The text to analyze.
+     *  @stable ICU 2.0
+     */
+    virtual void setText(const UnicodeString& newText);
+
+    /**
+     * 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);
+
+    /**
+     * Sets the current iteration position to the beginning of the text.
+     * @return The offset of the beginning of the text.
+     *  @stable ICU 2.0
+     */
+    virtual int32_t first(void);
+
+    /**
+     * 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);
+
+    /**
+     * 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);
+
+    /**
+     * 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);
+
+    /**
+     * 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);
+
+    /**
+     * 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);
+
+    /**
+     * 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);
+
+    /**
+     * Returns true if the specfied 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);
+
+    /**
+     * Returns the current iteration position.
+     * @return The current iteration position.
+     * @stable ICU 2.0
+     */
+    virtual int32_t current(void) const;
+
+
+    /**
+     * Return the status tag from the break rule that determined the most recently
+     * returned break 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>
+     * When creating custom break rules, one is free to define whatever
+     * status values may be convenient for the application.
+     * <p>
+     * Note: this function is not thread safe.  It should not have been
+     *       declared const, and the const remains only for compatibility
+     *       reasons.  (The function is logically const, but not bit-wise const).
+     * <p>
+     * @return the status from the break rule that determined the most recently
+     * returned break position.
+     *
+     * @see UWordBreak
+     * @stable ICU 2.2
+     */
+    virtual int32_t getRuleStatus() const;
+
+   /**
+    * Get the status (tag) values from the break rule(s) that determined the most
+    * recently returned break 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 attemtping to store any values.
+    * @param status    receives error codes.
+    * @return          The number of rule status values from rules that determined
+    *                  the most recent boundary returned by the break iterator.
+    *                  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);
+
+    /**
+     * 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;
+
+    /**
+     * 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);
+
+    /*
+     * 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 functoin 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 NULL,  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 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.
+     * @stable ICU 2.0
+     */
+    virtual BreakIterator *  createBufferClone(void *stackBuffer,
+                                               int32_t &BufferSize,
+                                               UErrorCode &status);
+
+
+    /**
+     * 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 paramter.)
+     *
+     * @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.
+     * @internal
+     */
+    virtual const uint8_t *getBinaryRules(uint32_t &length);
+
+
+protected:
+    //=======================================================================
+    // implementation
+    //=======================================================================
+    /**
+     * Dumps caches and performs other actions associated with a complete change
+     * in text or iteration position.
+     * @internal
+     */
+    virtual void reset(void);
+
+#if 0
+    /**
+      * Return true if the category lookup for this char
+      * indicates that it is in the set of dictionary lookup chars.
+      * This function is intended for use by dictionary based break iterators.
+      * @return true if the category lookup for this char
+      * indicates that it is in the set of dictionary lookup chars.
+      * @internal
+      */
+    virtual UBool isDictionaryChar(UChar32);
+
+    /**
+      * Get the type of the break iterator.
+      * @internal
+      */
+    virtual int32_t getBreakType() const;
+#endif
+
+    /**
+      * Set the type of the break iterator.
+      * @internal
+      */
+    virtual void setBreakType(int32_t type);
+
+    /**
+      * Common initialization function, used by constructors and bufferClone.
+      *   (Also used by DictionaryBasedBreakIterator::createBufferClone().)
+      * @internal
+      */
+    void init();
+
+private:
+
+    /**
+     * This method backs the iterator back up to a "safe position" in the text.
+     * This is a position that we know, without any context, must be a break position.
+     * The various calling methods then iterate forward from this safe position to
+     * the appropriate position to return.  (For more information, see the description
+     * of buildBackwardsStateTable() in RuleBasedBreakIterator.Builder.)
+     * @param statetable state table used of moving backwards
+     * @internal
+     */
+    int32_t handlePrevious(const RBBIStateTable *statetable);
+
+    /**
+     * This method is the actual implementation of the next() method.  All iteration
+     * vectors through here.  This method initializes the state machine to state 1
+     * and advances through the text character by character until we reach the end
+     * of the text or the state machine transitions to state 0.  We update our return
+     * value every time the state machine passes through a possible end state.
+     * @param statetable state table used of moving forwards
+     * @internal
+     */
+    int32_t handleNext(const RBBIStateTable *statetable);
+
+protected:
+
+    /**
+     * This is the function that actually implements dictionary-based
+     * breaking.  Covering at least the range from startPos to endPos,
+     * it checks for dictionary characters, and if it finds them determines
+     * the appropriate object to deal with them. It may cache found breaks in
+     * fCachedBreakPositions as it goes. It may well also look at text outside
+     * the range startPos to endPos.
+     * If going forward, endPos is the normal Unicode break result, and
+     * if goind in reverse, startPos is the normal Unicode break result
+     * @param startPos  The start position of a range of text
+     * @param endPos    The end position of a range of text
+     * @param reverse   The call is for the reverse direction
+     * @internal
+     */
+    int32_t checkDictionary(int32_t startPos, int32_t endPos, UBool reverse);
+
+private:
+
+    /**
+     * This function returns the appropriate LanguageBreakEngine for a
+     * given character c.
+     * @param c         A character in the dictionary set
+     * @internal
+     */
+    const LanguageBreakEngine *getLanguageBreakEngine(UChar32 c);
+
+    /**
+     *  @internal
+     */
+    void makeRuleStatusValid();
+
+};
+
+//------------------------------------------------------------------------------
+//
+//   Inline Functions Definitions ...
+//
+//------------------------------------------------------------------------------
+
+inline UBool RuleBasedBreakIterator::operator!=(const BreakIterator& that) const {
+    return !operator==(that);
+}
+
+U_NAMESPACE_END
+
+#endif /* #if !UCONFIG_NO_BREAK_ITERATION */
+
+#endif