The ICU API for processing regular expressions consists of two classes,
* RegexPattern and RegexMatcher.
* RegexPattern objects represent a pre-processed, or compiled
* regular expression. They are created from a regular expression pattern string,
* and can be used to create
Class RegexMatcher bundles together a regular expression
* pattern and a target string to which the search pattern will be applied.
* RegexMatcher includes API for doing plain find or search
* operations, for search and replace operations, and for obtaining detailed
* information about bounds of a match.
RegexPattern represents a compiled regular expression. It includes
* factory methods for creating a RegexPattern object from the source (string) form
* of a regular expression, methods for creating RegexMatchers that allow the pattern
* to be applied to input text, and a few convenience methods for simple common
* uses of regular expressions.
*
* Class RegexPattern is not intended to be subclassed.
* * @stable ICU 2.4 */ class U_I18N_API RegexPattern: public UObject { public: /** * default constructor. Create a RegexPattern object that refers to no actual * pattern. Not normally needed; RegexPattern objects are usually * created using the factory methodcompile().
*
* @stable ICU 2.4
*/
RegexPattern();
/**
* Copy Constructor. Create a new RegexPattern object that is equivalent
* to the source object.
* @stable ICU 2.4
*/
RegexPattern(const RegexPattern &source);
/**
* Destructor. Note that a RegexPattern object must persist so long as any
* RegexMatcher objects that were created from the RegexPattern are active.
* @stable ICU 2.4
*/
virtual ~RegexPattern();
/**
* Comparison operator. Two RegexPattern objects are considered equal if they
* were constructed from identical source patterns using the same match flag
* settings.
* @param that a RegexPattern object to compare with "this".
* @return TRUE if the objects are equivalent.
* @stable ICU 2.4
*/
UBool operator==(const RegexPattern& that) const;
/**
* Comparison operator. Two RegexPattern objects are considered equal if they
* were constructed from identical source patterns using the same match flag
* settings.
* @param that a RegexPattern object to compare with "this".
* @return TRUE if the objects are different.
* @stable ICU 2.4
*/
inline UBool operator!=(const RegexPattern& that) const {return ! operator ==(that);};
/**
* Assignment operator. After assignment, this RegexPattern will behave identically
* to the source object.
* @stable ICU 2.4
*/
RegexPattern &operator =(const RegexPattern &source);
/**
* Create an exact copy of this RegexPattern object. Since RegexPattern is not
* intended to be subclasses, clone() and the copy construction are
* equivalent operations.
* @return the copy of this RegexPattern
* @stable ICU 2.4
*/
virtual RegexPattern *clone() const;
/**
* Compiles the regular expression in string form into a RegexPattern
* object. These compile methods, rather than the constructors, are the usual
* way that RegexPattern objects are created.
*
* Note that RegexPattern objects must not be deleted while RegexMatcher * objects created from the pattern are active. RegexMatchers keep a pointer * back to their pattern, so premature deletion of the pattern is a * catastrophic error.
* *All pattern match mode flags are set to their default values.
* * @param regex The regular expression to be compiled. * @param pe Receives the position (line and column nubers) of any error * within the regular expression.) * @param status A reference to a UErrorCode to receive any errors. * @return A regexPattern object for the compiled pattern. * * @stable ICU 2.4 */ static RegexPattern *compile( const UnicodeString ®ex, UParseError &pe, UErrorCode &status); /** * Compiles the regular expression in string form into a RegexPattern * object using the specified match mode flags. These compile methods, * rather than the constructors, are the usual way that RegexPattern objects * are created. * *Note that RegexPattern objects must not be deleted while RegexMatcher * objects created from the pattern are active. RegexMatchers keep a pointer * back to their pattern, so premature deletion of the pattern is a * catastrophic error.
* * @param regex The regular expression to be compiled. * @param flags The match mode flags to be used. * @param pe Receives the position (line and column nubers) of any error * within the regular expression.) * @param status A reference to a UErrorCode to receive any errors. * @return A regexPattern object for the compiled pattern. * * @stable ICU 2.4 */ static RegexPattern *compile( const UnicodeString ®ex, uint32_t flags, UParseError &pe, UErrorCode &status); /** * Compiles the regular expression in string form into a RegexPattern * object using the specified match mode flags. These compile methods, * rather than the constructors, are the usual way that RegexPattern objects * are created. * *Note that RegexPattern objects must not be deleted while RegexMatcher * objects created from the pattern are active. RegexMatchers keep a pointer * back to their pattern, so premature deletion of the pattern is a * catastrophic error.
* * @param regex The regular expression to be compiled. * @param flags The match mode flags to be used. * @param status A reference to a UErrorCode to receive any errors. * @return A regexPattern object for the compiled pattern. * * @draft ICU 2.6 */ static RegexPattern *compile( const UnicodeString ®ex, uint32_t flags, UErrorCode &status); /** * Get the match mode flags that were used when compiling this pattern. * @return the match mode flags * @stable ICU 2.4 */ virtual uint32_t flags() const; /** * Creates a RegexMatcher that will match the given input against this pattern. The * RegexMatcher can then be used to perform match, find or replace operations * on the input. Note that a RegexPattern object must not be deleted while * RegexMatchers created from it still exist and might possibly be used again. * * @param input The input string to which the regular expression will be applied. * @param status A reference to a UErrorCode to receive any errors. * @return A RegexMatcher object for this pattern and input. * * @stable ICU 2.4 */ virtual RegexMatcher *matcher(const UnicodeString &input, UErrorCode &status) const; /** * Creates a RegexMatcher that will match against this pattern. The * RegexMatcher can be used to perform match, find or replace operations. * Note that a RegexPattern object must not be deleted while * RegexMatchers created from it still exist and might possibly be used again. * * @param status A reference to a UErrorCode to receive any errors. * @return A RegexMatcher object for this pattern and input. * * @draft ICU 2.6 */ virtual RegexMatcher *matcher(UErrorCode &status) const; /** * Test whether a string matches a regular expression. This convenience function * both compiles the reguluar expression and applies it in a single operation. * Note that if the same pattern needs to be applied repeatedly, this method will be * less efficient than creating and reusing a RegexPattern object. * * @param regex The regular expression * @param input The string data to be matched * @param pe Receives the position of any syntax errors within the regular expression * @param status A reference to a UErrorCode to receive any errors. * @return True if the regular expression exactly matches the full input string. * * @stable ICU 2.4 */ static UBool matches(const UnicodeString ®ex, const UnicodeString &input, UParseError &pe, UErrorCode &status); /** * Returns the regular expression from which this pattern was compiled. * @stable ICU 2.4 */ virtual UnicodeString pattern() const; /** * Split a string into fields. Somewhat like split() from Perl. * The pattern matches identify delimiters that separate the input * into fields. The input data between the matches becomes the * fields themselves. *
* For the best performance on split() operations,
* RegexMatcher::split is perferable to this function
*
* @param input The string to be split into fields. The field delimiters
* match the pattern (in the "this" object)
* @param dest An array of UnicodeStrings to receive the results of the split.
* This is an array of actual UnicodeString objects, not an
* array of pointers to strings. Local (stack based) arrays can
* work well here.
* @param destCapacity The number of elements in the destination array.
* If the number of fields found is less than destCapacity, the
* extra strings in the destination array are not altered.
* If the number of destination strings is less than the number
* of fields, the trailing part of the input string, including any
* field delimiters, is placed in the last destination string.
* @param status A reference to a UErrorCode to receive any errors.
* @return The number of fields into which the input string was split.
* @stable ICU 2.4
*/
virtual int32_t split(const UnicodeString &input,
UnicodeString dest[],
int32_t destCapacity,
UErrorCode &status) const;
/**
* ICU "poor man's RTTI", returns a UClassID for the actual class.
*
* @stable ICU 2.4
*/
virtual UClassID getDynamicClassID() const;
/**
* ICU "poor man's RTTI", returns a UClassID for this class.
*
* @stable ICU 2.4
*/
static UClassID getStaticClassID();
private:
//
// Implementation Data
//
UnicodeString fPattern; // The original pattern string.
uint32_t fFlags; // The flags used when compiling the pattern.
//
UVector32 *fCompiledPat; // The compiled pattern p-code.
UnicodeString fLiteralText; // Any literal string data from the pattern,
// after un-escaping, for use during the match.
UVector *fSets; // Any UnicodeSets referenced from the pattern.
Regex8BitSet *fSets8; // (and fast sets for latin-1 range.)
UErrorCode fDeferredStatus; // status if some prior error has left this
// RegexPattern in an unusable state.
int32_t fMinMatchLen; // Minimum Match Length. All matches will have length
// >= this value. For some patterns, this calculated
// value may be less than the true shortest
// possible match.
int32_t fFrameSize; // Size of a state stack frame in the
// execution engine.
int32_t fDataSize; // The size of the data needed by the pattern that
// does not go on the state stack, but has just
// a single copy per matcher.
UVector32 *fGroupMap; // Map from capture group number to position of
// the group's variables in the matcher stack frame.
int32_t fMaxCaptureDigits;
UnicodeSet **fStaticSets; // Ptr to static (shared) sets for predefined
// regex character classes, e.g. Word.
Regex8BitSet *fStaticSets8; // Ptr to the static (shared) latin-1 only
// sets for predefined regex classes.
int32_t fStartType; // Info on how a match must start.
int32_t fInitialStringIdx; //
int32_t fInitialStringLen;
UnicodeSet *fInitialChars;
UChar32 fInitialChar;
Regex8BitSet *fInitialChars8;
friend class RegexCompile;
friend class RegexMatcher;
friend class RegexCImpl;
//
// Implementation Methods
//
void init(); // Common initialization, for use by constructors.
void zap(); // Common cleanup
#ifdef REGEX_DEBUG
void dumpOp(int32_t index) const;
friend void RegexPatternDump(const RegexPattern *);
#endif
};
/**
* class RegexMatcher bundles together a reular expression pattern and
* input text to which the expression can be applied. It includes methods
* for testing for matches, and for find and replace operations.
*
*
Class RegexMatcher is not intended to be subclassed.
* * @stable ICU 2.4 */ class U_I18N_API RegexMatcher: public UObject { public: /** * Construct a RegexMatcher for a regular expression. * This is a convenience method that avoids the need to explicitly create * a RegexPattern object. Note that if several RegexMatchers need to be * created for the same expression, it will be more efficient to * separately create and cache a RegexPattern object, and use * its matcher() method to create the RegexMatcher objects. * * @param regexp The Regular Expression to be compiled. * @param flags Regular expression options, such as case insensitive matching. * @see UREGEX_CASE_INSENSITIVE * @param status Any errors are reported by setting this UErrorCode variable. * @draft ICU 2.6 */ RegexMatcher(const UnicodeString ®exp, uint32_t flags, UErrorCode &status); /** * Construct a RegexMatcher for a regular expression. * This is a convenience method that avoids the need to explicitly create * a RegexPattern object. Note that if several RegexMatchers need to be * created for the same expression, it will be more efficient to * separately create and cache a RegexPattern object, and use * its matcher() method to create the RegexMatcher objects. * * @param regexp The Regular Expression to be compiled. * @param input The string to match * @param flags Regular expression options, such as case insensitive matching. * @see UREGEX_CASE_INSENSITIVE * @param status Any errors are reported by setting this UErrorCode variable. * @draft ICU 2.6 */ RegexMatcher(const UnicodeString ®exp, const UnicodeString &input, uint32_t flags, UErrorCode &status); /** * Destructor. * * @stable ICU 2.4 */ virtual ~RegexMatcher(); /** * Attempts to match the entire input string against the pattern. * @param status A reference to a UErrorCode to receive any errors. * @return TRUE if there is a match * @stable ICU 2.4 */ virtual UBool matches(UErrorCode &status); /** * Attempts to match the input string, beginning at startIndex, against the pattern. * The match must extend to the end of the input string. * @param startIndex The input string index at which to begin matching. * @param status A reference to a UErrorCode to receive any errors. * @return TRUE if there is a match * @draft ICU 2.8 */ virtual UBool matches(int32_t startIndex, UErrorCode &status); /** * Attempts to match the input string, starting from the beginning, against the pattern. * Like the matches() method, this function always starts at the beginning of the input string; * unlike that function, it does not require that the entire input string be matched. * *If the match succeeds then more information can be obtained via the start(),
* end(), and group() functions.
If the match succeeds then more information can be obtained via the start(),
* end(), and group() functions.
start(), end() and group()
* will provide more information regarding the match.
* Note that if the input string is changed by the application, * use find(startPos, status) instead of find(), because the saved starting * position may not be valid with the altered input string.
* @return TRUE if a match is found. * @stable ICU 2.4 */ virtual UBool find(); /** * Resets this RegexMatcher and then attempts to find the next substring of the * input string that matches the pattern, starting at the specified index. * * @param start the position in the input string to begin the search * @param status A reference to a UErrorCode to receive any errors. * @return TRUE if a match is found. * @stable ICU 2.4 */ virtual UBool find(int32_t start, UErrorCode &status); /** * Returns a string containing the text matched by the previous match. * If the pattern can match an empty string, an empty string may be returned. * @param status A reference to a UErrorCode to receive any errors. * Possible errors are U_REGEX_INVALID_STATE if no match * has been attempted or the last match failed. * @return a string containing the matched input text. * @stable ICU 2.4 */ virtual UnicodeString group(UErrorCode &status) const; /** * Returns a string containing the text captured by the given group * during the previous match operation. Group(0) is the entire match. * * @param groupNum the capture group number * @param status A reference to a UErrorCode to receive any errors. * Possible errors are U_REGEX_INVALID_STATE if no match * has been attempted or the last match failed and * U_INDEX_OUTOFBOUNDS_ERROR for a bad capture group number. * @return the captured text * @stable ICU 2.4 */ virtual UnicodeString group(int32_t groupNum, UErrorCode &status) const; /** * Returns the number of capturing groups in this matcher's pattern. * @return the number of capture groups * @stable ICU 2.4 */ virtual int32_t groupCount() const; /** * Returns the index in the input string of the start of the text matched * during the previous match operation. * @param status a reference to a UErrorCode to receive any errors. * @return The position in the input string of the start of the last match. * @stable ICU 2.4 */ virtual int32_t start(UErrorCode &status) const; /** * Returns the index in the input string of the start of the text matched by the * specified capture group during the previous match operation. Return -1 if * the capture group exists in the pattern, but was not part of the last match. * * @param group the capture group number * @param status A reference to a UErrorCode to receive any errors. Possible * errors are U_REGEX_INVALID_STATE if no match has been * attempted or the last match failed, and * U_INDEX_OUTOFBOUNDS_ERROR for a bad capture group number * @return the start position of substring matched by the specified group. * @stable ICU 2.4 */ virtual int32_t start(int group, UErrorCode &status) const; /** * Returns the index in the input string of the character following the * text matched during the previous match operation. * @param status A reference to a UErrorCode to receive any errors. Possible * errors are U_REGEX_INVALID_STATE if no match has been * attempted or the last match failed. * @return the index of the last character matched, plus one. * @stable ICU 2.4 */ virtual int32_t end(UErrorCode &status) const; /** * Returns the index in the input string of the character following the * text matched by the specified capture group during the previous match operation. * @param group the capture group number * @param status A reference to a UErrorCode to receive any errors. Possible * errors are U_REGEX_INVALID_STATE if no match has been * attempted or the last match failed and * U_INDEX_OUTOFBOUNDS_ERROR for a bad capture group number * @return the index of the last character, plus one, of the text * captured by the specifed group during the previous match operation. * Return -1 if the capture group was not part of the match. * @stable ICU 2.4 */ virtual int32_t end(int group, UErrorCode &status) const; /** * Resets this matcher. The effect is to remove any memory of previous matches, * and to cause subsequent find() operations to begin at the beginning of * the input string. * * @return this RegexMatcher. * @stable ICU 2.4 */ virtual RegexMatcher &reset(); /** * Resets this matcher, and set the current input position. * The effect is to remove any memory of previous matches, * and to cause subsequent find() operations to begin at * the specified position in the input string. * * @return this RegexMatcher. * @draft ICU 2.8 */ virtual RegexMatcher &reset(int32_t index, UErrorCode &status); /** * Resets this matcher with a new input string. This allows instances of RegexMatcher * to be reused, which is more efficient than creating a new RegexMatcher for * each input string to be processed. * @return this RegexMatcher. * @stable ICU 2.4 */ virtual RegexMatcher &reset(const UnicodeString &input); /** * Returns the input string being matched. The returned string is not a copy, * but the live input string. It should not be altered or deleted. * @return the input string * @stable ICU 2.4 */ virtual const UnicodeString &input() const; /** * Returns the pattern that is interpreted by this matcher. * @return the RegexPattern for this RegexMatcher * @stable ICU 2.4 */ virtual const RegexPattern &pattern() const; /** * Replaces every substring of the input that matches the pattern * with the given replacement string. This is a convenience function that * provides a complete find-and-replace-all operation. * * This method first resets this matcher. It then scans the input string * looking for matches of the pattern. Input that is not part of any * match is left unchanged; each match is replaced in the result by the * replacement string. The replacement string may contain references to * capture groups. * * @param replacement a string containing the replacement text. * @param status a reference to a UErrorCode to receive any errors. * @return a string containing the results of the find and replace. * @stable ICU 2.4 */ virtual UnicodeString replaceAll(const UnicodeString &replacement, UErrorCode &status); /** * Replaces the first substring of the input that matches * the pattern with the replacement string. This is a convenience * function that provides a complete find-and-replace operation. * *This function first resets this RegexMatcher. It then scans the input string * looking for a match of the pattern. Input that is not part * of the match is appended directly to the result string; the match is replaced * in the result by the replacement string. The replacement string may contain * references to captured groups.
* *The state of the matcher (the position at which a subsequent find() * would begin) after completing a replaceFirst() is not specified. The * RegexMatcher should be reset before doing additional find() operations.
* * @param replacement a string containing the replacement text. * @param status a reference to a UErrorCode to receive any errors. * @return a string containing the results of the find and replace. * @stable ICU 2.4 */ virtual UnicodeString replaceFirst(const UnicodeString &replacement, UErrorCode &status); /** * Implements a replace operation intended to be used as part of an * incremental find-and-replace. * *The input string, starting from the end of the previous match and ending at * the start of the current match, is appended to the destination string. Then the * replacement string is appended to the output string, * including handling any substitutions of captured text.
* *For simple, prepackaged, non-incremental find-and-replace * operations, see replaceFirst() or replaceAll().
* * @param dest A UnicodeString to which the results of the find-and-replace are appended. * @param replacement A UnicodeString that provides the text to be substituted for * the input text that matched the regexp pattern. The replacement * text may contain references to captured text from the * input. * @param status A reference to a UErrorCode to receive any errors. Possible * errors are U_REGEX_INVALID_STATE if no match has been * attempted or the last match failed, and U_INDEX_OUTOFBOUNDS_ERROR * if the replacement text specifies a capture group that * does not exist in the pattern. * * @return this RegexMatcher * @stable ICU 2.4 * */ virtual RegexMatcher &appendReplacement(UnicodeString &dest, const UnicodeString &replacement, UErrorCode &status); /** * As the final step in a find-and-replace operation, append the remainder * of the input string, starting at the position following the last match, * to the destination string.appendTail() is intended to be invoked after one
* or more invocations of the RegexMatcher::appendReplacement().
*
* @param dest A UnicodeString to which the results of the find-and-replace are appended.
* @return the destination string.
* @stable ICU 2.4
*/
virtual UnicodeString &appendTail(UnicodeString &dest);
/**
* Split a string into fields. Somewhat like split() from Perl.
* The pattern matches identify delimiters that separate the input
* into fields. The input data between the matches becomes the
* fields themselves.
* * * @param input The string to be split into fields. The field delimiters * match the pattern (in the "this" object). This matcher * will be reset to this input string. * @param dest An array of UnicodeStrings to receive the results of the split. * This is an array of actual UnicodeString objects, not an * array of pointers to strings. Local (stack based) arrays can * work well here. * @param destCapacity The number of elements in the destination array. * If the number of fields found is less than destCapacity, the * extra strings in the destination array are not altered. * If the number of destination strings is less than the number * of fields, the trailing part of the input string, including any * field delimiters, is placed in the last destination string. * @param status A reference to a UErrorCode to receive any errors. * @return The number of fields into which the input string was split. * @draft ICU 2.6 */ virtual int32_t split(const UnicodeString &input, UnicodeString dest[], int32_t destCapacity, UErrorCode &status); /** * setTrace Debug function, enable/disable tracing of the matching engine. * For internal ICU development use only. DO NO USE!!!! * @internal */ void setTrace(UBool state); /** * ICU "poor man's RTTI", returns a UClassID for this class. * * @stable ICU 2.2 */ static UClassID getStaticClassID(); /** * ICU "poor man's RTTI", returns a UClassID for the actual class. * * @stable ICU 2.2 */ virtual UClassID getDynamicClassID() const; private: // Constructors and other object boilerplate are private. // Instances of RegexMatcher can not be assigned, copied, cloned, etc. RegexMatcher(); // default constructor not implemented RegexMatcher(const RegexPattern *pat); RegexMatcher(const RegexMatcher &other); RegexMatcher &operator =(const RegexMatcher &rhs); friend class RegexPattern; friend class RegexCImpl; // // MatchAt This is the internal interface to the match engine itself. // Match status comes back in matcher member variables. // void MatchAt(int32_t startIdx, UErrorCode &status); inline void backTrack(int32_t &inputIdx, int32_t &patIdx); UBool isWordBoundary(int32_t pos); // perform Perl-like \b test UBool isUWordBoundary(int32_t pos); // perform RBBI based \b test REStackFrame *resetStack(); inline REStackFrame *StateSave(REStackFrame *fp, int32_t savePatIdx, int32_t frameSize, UErrorCode &status); const RegexPattern *fPattern; RegexPattern *fPatternOwned; // Non-NULL if this matcher owns the pattern, and // should delete it when through. const UnicodeString *fInput; UBool fMatch; // True if the last match was successful. int32_t fMatchStart; // Position of the start of the most recent match int32_t fMatchEnd; // First position after the end of the most recent match int32_t fLastMatchEnd; // First position after the end of the previous match. UVector32 *fStack; REStackFrame *fFrame; // After finding a match, the last active stack // frame, which will contain the capture group results. // NOT valid while match engine is running. int32_t *fData; // Data area for use by the compiled pattern. int32_t fSmallData[8]; // Use this for data if it's enough. UBool fTraceDebug; // Set true for debug tracing of match engine. UErrorCode fDeferredStatus; // Save error state if that cannot be immediately // reported, or that permanently disables this matcher. RuleBasedBreakIterator *fWordBreakItr; }; U_NAMESPACE_END #endif // UCONFIG_NO_REGULAR_EXPRESSIONS #endif