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/*
***************************************************************************
* 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