RuleBasedBreakIterator Class Reference

A subclass of BreakIterator whose behavior is specified using a list of rules. More...

#include <rbbi.h>

Inheritance diagram for RuleBasedBreakIterator:

BreakIterator UObject UMemory DictionaryBasedBreakIterator

Public Member Functions

 RuleBasedBreakIterator ()
 Default constructor.
 RuleBasedBreakIterator (const RuleBasedBreakIterator &that)
 Copy constructor.
 RuleBasedBreakIterator (const UnicodeString &rules, UParseError &parseError, UErrorCode &status)
 Construct a RuleBasedBreakIterator from a set of rules supplied as a string.
 RuleBasedBreakIterator (UDataMemory *image, UErrorCode &status)
 This constructor uses the udata interface to create a BreakIterator whose internal tables live in a memory-mapped file.
virtual ~RuleBasedBreakIterator ()
 Destructor.
RuleBasedBreakIteratoroperator= (const RuleBasedBreakIterator &that)
 Assignment operator.
virtual UBool operator== (const BreakIterator &that) const
 Equality operator.
UBool operator!= (const BreakIterator &that) const
 Not-equal operator.
virtual BreakIteratorclone () const
 Returns a newly-constructed RuleBasedBreakIterator with the same behavior, and iterating over the same text, as this one.
virtual int32_t hashCode (void) const
 Compute a hash code for this BreakIterator.
virtual const UnicodeStringgetRules (void) const
 Returns the description used to create this iterator.
virtual const CharacterIteratorgetText (void) const
 Return a CharacterIterator over the text being analyzed.
virtual UTextgetUText (UText *fillIn, UErrorCode &status) const
 Get a UText for the text being analyzed.
virtual void adoptText (CharacterIterator *newText)
 Set the iterator to analyze a new piece of text.
virtual void setText (const UnicodeString &newText)
 Set the iterator to analyze a new piece of text.
virtual void setText (UText *text, UErrorCode &status)
 Reset the break iterator to operate over the text represented by the UText.
virtual int32_t first (void)
 Sets the current iteration position to the beginning of the text.
virtual int32_t last (void)
 Sets the current iteration position to the end of the text.
virtual int32_t next (int32_t n)
 Advances the iterator either forward or backward the specified number of steps.
virtual int32_t next (void)
 Advances the iterator to the next boundary position.
virtual int32_t previous (void)
 Moves the iterator backwards, to the last boundary preceding this one.
virtual int32_t following (int32_t offset)
 Sets the iterator to refer to the first boundary position following the specified position.
virtual int32_t preceding (int32_t offset)
 Sets the iterator to refer to the last boundary position before the specified position.
virtual UBool isBoundary (int32_t offset)
 Returns true if the specfied position is a boundary position.
virtual int32_t current (void) const
 Returns the current iteration position.
virtual int32_t getRuleStatus () const
 Return the status tag from the break rule that determined the most recently returned break position.
virtual int32_t getRuleStatusVec (int32_t *fillInVec, int32_t capacity, UErrorCode &status)
 Get the status (tag) values from the break rule(s) that determined the most recently returned break position.
virtual UClassID getDynamicClassID (void) const
 Returns a unique class ID POLYMORPHICALLY.
virtual BreakIteratorcreateBufferClone (void *stackBuffer, int32_t &BufferSize, UErrorCode &status)
 Thread safe client-buffer-based cloning operation Do NOT call delete on a safeclone, since 'new' is not used to create it.
virtual const uint8_tgetBinaryRules (uint32_t &length)
 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.

Static Public Member Functions

static UClassID U_EXPORT2 getStaticClassID (void)
 Returns the class ID for this class.

Protected Member Functions

 RuleBasedBreakIterator (RBBIDataHeader *data, UErrorCode &status)
 Constructor from a flattened set of RBBI data in malloced memory.
virtual int32_t handleNext (void)
 This method is the actual implementation of the next() method.
virtual int32_t handlePrevious (void)
 This method backs the iterator back up to a "safe position" in the text.
virtual void reset (void)
 Dumps caches and performs other actions associated with a complete change in text or iteration position.
virtual UBool isDictionaryChar (UChar32)
 Return true if the category lookup for this char indicates that it is in the set of dictionary lookup chars.
void init ()
 Common initialization function, used by constructors and bufferClone.

Protected Attributes

CharacterIteratorfText
 The character iterator through which this BreakIterator accesses the text.
RBBIDataWrapper * fData
 The rule data for this BreakIterator instance.
int32_t fLastRuleStatusIndex
 Index of the Rule {tag} values for the most recent match.
UBool fLastStatusIndexValid
 Rule tag value valid flag.
uint32_t fDictionaryCharCount
 Counter for the number of characters encountered with the "dictionary" flag set.

Static Protected Attributes

static UBool fTrace
 Debugging flag.

Friends

class RBBIRuleBuilder
class BreakIterator

Detailed Description

A subclass of BreakIterator whose behavior is specified using a list of rules.

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 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.

Definition at line 59 of file rbbi.h.


Constructor & Destructor Documentation

RuleBasedBreakIterator::RuleBasedBreakIterator RBBIDataHeader *  data,
UErrorCode status
[protected]
 

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:
Do not use. This API is for interal use only.

RuleBasedBreakIterator::RuleBasedBreakIterator  ) 
 

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::RuleBasedBreakIterator const RuleBasedBreakIterator that  ) 
 

Copy constructor.

Will produce a break iterator with the same behavior, and which iterates over the same text, as the one passed in.

Parameters:
that The RuleBasedBreakIterator passed to be copied
Stable:
ICU 2.0

RuleBasedBreakIterator::RuleBasedBreakIterator const UnicodeString rules,
UParseError parseError,
UErrorCode status
 

Construct a RuleBasedBreakIterator from a set of rules supplied as a string.

Parameters:
rules The break rules to be used.
parseError In the event of a syntax error in the rules, provides the location within the rules of the problem.
status Information on any errors encountered.
Stable:
ICU 2.2

RuleBasedBreakIterator::RuleBasedBreakIterator UDataMemory image,
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.

Parameters:
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.
status Information on any errors encountered.
See also:
udata_open

getBinaryRules

Stable:
ICU 2.8

virtual RuleBasedBreakIterator::~RuleBasedBreakIterator  )  [virtual]
 

Destructor.

Stable:
ICU 2.0


Member Function Documentation

virtual void RuleBasedBreakIterator::adoptText CharacterIterator newText  )  [virtual]
 

Set the iterator to analyze a new piece of text.

This function resets the current iteration position to the beginning of the text.

Parameters:
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

Implements BreakIterator.

virtual BreakIterator* RuleBasedBreakIterator::clone  )  const [virtual]
 

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.

Returns:
a newly-constructed RuleBasedBreakIterator
Stable:
ICU 2.0

Implements BreakIterator.

Reimplemented in DictionaryBasedBreakIterator.

virtual BreakIterator* RuleBasedBreakIterator::createBufferClone void *  stackBuffer,
int32_t BufferSize,
UErrorCode status
[virtual]
 

Thread safe client-buffer-based cloning operation Do NOT call delete on a safeclone, since 'new' is not used to create it.

Parameters:
stackBuffer user allocated space for the new clone. If NULL new memory will be allocated. If buffer is not large enough, new memory will be allocated.
BufferSize reference to size of allocated space. If BufferSize == 0, a sufficient size for use in cloning will be returned ('pre-flighting') If BufferSize is not enough for a stack-based safe clone, new memory will be allocated.
status to indicate whether the operation went on smoothly or there were errors An informational status value, U_SAFECLONE_ALLOCATED_ERROR, is used if any allocations were necessary.
Returns:
pointer to the new clone
Stable:
ICU 2.0

Implements BreakIterator.

Reimplemented in DictionaryBasedBreakIterator.

virtual int32_t RuleBasedBreakIterator::current void   )  const [virtual]
 

Returns the current iteration position.

Returns:
The current iteration position.
Stable:
ICU 2.0

Implements BreakIterator.

virtual int32_t RuleBasedBreakIterator::first void   )  [virtual]
 

Sets the current iteration position to the beginning of the text.

(i.e., the CharacterIterator's starting offset).

Returns:
The offset of the beginning of the text.
Stable:
ICU 2.0

Implements BreakIterator.

virtual int32_t RuleBasedBreakIterator::following int32_t  offset  )  [virtual]
 

Sets the iterator to refer to the first boundary position following the specified position.

Parameters:
offset The position from which to begin searching for a break position.
Returns:
The position of the first break after the current position.
Stable:
ICU 2.0

Implements BreakIterator.

Reimplemented in DictionaryBasedBreakIterator.

virtual const uint8_t* RuleBasedBreakIterator::getBinaryRules uint32_t length  )  [virtual]
 

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)

Parameters:
length Returns the length of the binary data. (Out paramter.)
Returns:
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:
Do not use. This API is for interal use only.

virtual UClassID RuleBasedBreakIterator::getDynamicClassID void   )  const [virtual]
 

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.

Returns:
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

Implements BreakIterator.

Reimplemented in DictionaryBasedBreakIterator.

virtual const UnicodeString& RuleBasedBreakIterator::getRules void   )  const [virtual]
 

Returns the description used to create this iterator.

Returns:
the description used to create this iterator
Stable:
ICU 2.0

virtual int32_t RuleBasedBreakIterator::getRuleStatus  )  const [virtual]
 

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.

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.

When creating custom break rules, one is free to define whatever status values may be convenient for the application.

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).

Returns:
the status from the break rule that determined the most recently returned break position.
See also:
UWordBreak
Stable:
ICU 2.2

virtual int32_t RuleBasedBreakIterator::getRuleStatusVec int32_t fillInVec,
int32_t  capacity,
UErrorCode status
[virtual]
 

Get the status (tag) values from the break rule(s) that determined the most recently returned break 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.

Parameters:
fillInVec an array to be filled in with the status values.
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.
status receives error codes.
Returns:
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 also:
getRuleStatus
Draft:
This API may be changed in the future versions and was introduced in ICU 3.0

static UClassID U_EXPORT2 RuleBasedBreakIterator::getStaticClassID void   )  [static]
 

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()) ...

Returns:
The class ID for all objects of this class.
Stable:
ICU 2.0

Reimplemented in DictionaryBasedBreakIterator.

virtual const CharacterIterator& RuleBasedBreakIterator::getText void   )  const [virtual]
 

Return a CharacterIterator over the text being analyzed.

This version of this method returns the actual CharacterIterator we're using internally. Changing the state of this iterator can have undefined consequences. If you need to change it, clone it first.

Returns:
An iterator over the text being analyzed.
Stable:
ICU 2.0

Implements BreakIterator.

virtual UText* RuleBasedBreakIterator::getUText UText fillIn,
UErrorCode status
const [virtual]
 

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.

Parameters:
fillIn A UText to be filled in. If NULL, a new UText will be allocated to hold the result.
status receives any error codes.
Returns:
The current UText for this break iterator. If an input UText was provided, it will always be returned.
Draft:
This API may be changed in the future versions and was introduced in ICU 3.4

Implements BreakIterator.

virtual int32_t RuleBasedBreakIterator::handleNext void   )  [protected, virtual]
 

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.

Internal:
Do not use. This API is for interal use only.

Reimplemented in DictionaryBasedBreakIterator.

virtual int32_t RuleBasedBreakIterator::handlePrevious void   )  [protected, virtual]
 

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.)

Internal:
Do not use. This API is for interal use only.

virtual int32_t RuleBasedBreakIterator::hashCode void   )  const [virtual]
 

Compute a hash code for this BreakIterator.

Returns:
A hash code
Stable:
ICU 2.0

void RuleBasedBreakIterator::init  )  [protected]
 

Common initialization function, used by constructors and bufferClone.

(Also used by DictionaryBasedBreakIterator::createBufferClone().)

Internal:
Do not use. This API is for interal use only.

Reimplemented in DictionaryBasedBreakIterator.

virtual UBool RuleBasedBreakIterator::isBoundary int32_t  offset  )  [virtual]
 

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".

Parameters:
offset the offset to check.
Returns:
True if "offset" is a boundary position.
Stable:
ICU 2.0

Implements BreakIterator.

virtual UBool RuleBasedBreakIterator::isDictionaryChar UChar32   )  [protected, virtual]
 

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.

Returns:
true if the category lookup for this char indicates that it is in the set of dictionary lookup chars.
Internal:
Do not use. This API is for interal use only.

virtual int32_t RuleBasedBreakIterator::last void   )  [virtual]
 

Sets the current iteration position to the end of the text.

(i.e., the CharacterIterator's ending offset).

Returns:
The text's past-the-end offset.
Stable:
ICU 2.0

Implements BreakIterator.

virtual int32_t RuleBasedBreakIterator::next void   )  [virtual]
 

Advances the iterator to the next boundary position.

Returns:
The position of the first boundary after this one.
Stable:
ICU 2.0

Implements BreakIterator.

virtual int32_t RuleBasedBreakIterator::next int32_t  n  )  [virtual]
 

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().

Parameters:
n The number of steps to move. The sign indicates the direction (negative is backwards, and positive is forwards).
Returns:
The character offset of the boundary position n boundaries away from the current one.
Stable:
ICU 2.0

Implements BreakIterator.

UBool RuleBasedBreakIterator::operator!= const BreakIterator that  )  const [inline]
 

Not-equal operator.

If operator== returns TRUE, this returns FALSE, and vice versa.

Parameters:
that The BreakIterator to be compared for inequality
Returns:
TRUE if both BreakIterators are not same.
Stable:
ICU 2.0

Reimplemented from BreakIterator.

Definition at line 591 of file rbbi.h.

References operator==().

RuleBasedBreakIterator& RuleBasedBreakIterator::operator= const RuleBasedBreakIterator that  ) 
 

Assignment operator.

Sets this iterator to have the same behavior, and iterate over the same text, as the one passed in.

Parameters:
that The RuleBasedBreakItertor passed in
Returns:
the newly created RuleBasedBreakIterator
Stable:
ICU 2.0

virtual UBool RuleBasedBreakIterator::operator== const BreakIterator that  )  const [virtual]
 

Equality operator.

Returns TRUE if both BreakIterators are of the same class, have the same behavior, and iterate over the same text.

Parameters:
that The BreakIterator to be compared for equality
Returns:
TRUE if both BreakIterators are of the same class, have the same behavior, and iterate over the same text.
Stable:
ICU 2.0

Implements BreakIterator.

Referenced by operator!=().

virtual int32_t RuleBasedBreakIterator::preceding int32_t  offset  )  [virtual]
 

Sets the iterator to refer to the last boundary position before the specified position.

Parameters:
offset The position to begin searching for a break from.
Returns:
The position of the last boundary before the starting position.
Stable:
ICU 2.0

Implements BreakIterator.

Reimplemented in DictionaryBasedBreakIterator.

virtual int32_t RuleBasedBreakIterator::previous void   )  [virtual]
 

Moves the iterator backwards, to the last boundary preceding this one.

Returns:
The position of the last boundary position preceding this one.
Stable:
ICU 2.0

Implements BreakIterator.

Reimplemented in DictionaryBasedBreakIterator.

virtual void RuleBasedBreakIterator::reset void   )  [protected, virtual]
 

Dumps caches and performs other actions associated with a complete change in text or iteration position.

This function is a no-op in RuleBasedBreakIterator, but subclasses can and do override it.

Internal:
Do not use. This API is for interal use only.

Reimplemented in DictionaryBasedBreakIterator.

virtual void RuleBasedBreakIterator::setText UText text,
UErrorCode status
[virtual]
 

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.

Parameters:
text The UText used to change the text.
status Receives any error codes.
Draft:
This API may be changed in the future versions and was introduced in ICU 3.4

Implements BreakIterator.

virtual void RuleBasedBreakIterator::setText const UnicodeString newText  )  [virtual]
 

Set the iterator to analyze a new piece of text.

This function resets the current iteration position to the beginning of the text.

Parameters:
newText The text to analyze.
Stable:
ICU 2.0

Implements BreakIterator.


Friends And Related Function Documentation

friend class BreakIterator [friend]
 

Internal:
Do not use. This API is for interal use only.

Reimplemented in DictionaryBasedBreakIterator.

Definition at line 123 of file rbbi.h.

friend class RBBIRuleBuilder [friend]
 

Internal:
Do not use. This API is for interal use only.

Definition at line 121 of file rbbi.h.


Field Documentation

RBBIDataWrapper* RuleBasedBreakIterator::fData [protected]
 

The rule data for this BreakIterator instance.

Internal:
Do not use. This API is for interal use only.

Definition at line 72 of file rbbi.h.

uint32_t RuleBasedBreakIterator::fDictionaryCharCount [protected]
 

Counter for the number of characters encountered with the "dictionary" flag set.

Normal RBBI iterators don't use it, although the code for updating it is live. Dictionary Based break iterators (a subclass of us) access this field directly.

Internal:
Do not use. This API is for interal use only.

Definition at line 94 of file rbbi.h.

int32_t RuleBasedBreakIterator::fLastRuleStatusIndex [protected]
 

Index of the Rule {tag} values for the most recent match.

Internal:
Do not use. This API is for interal use only.

Definition at line 77 of file rbbi.h.

UBool RuleBasedBreakIterator::fLastStatusIndexValid [protected]
 

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:
Do not use. This API is for interal use only.

Definition at line 85 of file rbbi.h.

CharacterIterator* RuleBasedBreakIterator::fText [protected]
 

The character iterator through which this BreakIterator accesses the text.

Internal:
Do not use. This API is for interal use only.

Definition at line 66 of file rbbi.h.

UBool RuleBasedBreakIterator::fTrace [static, protected]
 

Debugging flag.

Trace operation of state machine when true.

Internal:
Do not use. This API is for interal use only.

Definition at line 100 of file rbbi.h.


The documentation for this class was generated from the following file:
Generated on Tue Sep 13 11:03:28 2005 for ICU 3.4 by  doxygen 1.4.4