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/*
**********************************************************************
*   Copyright (C) 2002-2012, International Business Machines
*   Corporation and others.  All Rights Reserved.
**********************************************************************
*   file name:  regex.h
*   encoding:   US-ASCII
*   indentation:4
*
*   created on: 2002oct22
*   created by: Andy Heninger
*
*   ICU Regular Expressions, API for C++
*/

#ifndef REGEX_H
#define REGEX_H

//#define REGEX_DEBUG

/**
 * \file
 * \brief  C++ API:  Regular Expressions
 *
 * <h2>Regular Expression API</h2>
 *
 * <p>The ICU API for processing regular expressions consists of two
classes,
 *  <code>RegexPattern</code> and
<code>RegexMatcher</code>.
 *  <code>RegexPattern</code> objects represent a
pre-processed, or compiled
 *  regular expression.  They are created from a regular expression pattern
string,
 *  and can be used to create <code>RegexMatcher</code> objects
for the pattern.</p>
 *
 * <p>Class <code>RegexMatcher</code> bundles together a
regular expression
 *  pattern and a target string to which the search pattern will be
applied.
 *  <code>RegexMatcher</code> includes API for doing plain find
or search
 *  operations, for search and replace operations, and for obtaining
detailed
 *  information about bounds of a match. </p>
 *
 * <p>Note that by constructing <code>RegexMatcher</code>
objects directly from regular
 * expression pattern strings application code can be simplified and the
explicit
 * need for <code>RegexPattern</code> objects can usually be
eliminated.
 * </p>
 */

#include "unicode/utypes.h"

#if !UCONFIG_NO_REGULAR_EXPRESSIONS

#include "unicode/uobject.h"
#include "unicode/unistr.h"
#include "unicode/utext.h"
#include "unicode/parseerr.h"

#include "unicode/uregex.h"

// Forward Declarations

U_NAMESPACE_BEGIN

struct Regex8BitSet;
class  RegexCImpl;
class  RegexMatcher;
class  RegexPattern;
struct REStackFrame;
class  RuleBasedBreakIterator;
class  UnicodeSet;
class  UVector;
class  UVector32;
class  UVector64;

/**
 *   RBBIPatternDump   Debug function, displays the compiled form of a
pattern.
 *   @internal
 */
#ifdef REGEX_DEBUG
U_INTERNAL void U_EXPORT2
    RegexPatternDump(const RegexPattern *pat);
#else
    #undef RegexPatternDump
    #define RegexPatternDump(pat)
#endif



/**
  * Class <code>RegexPattern</code> 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.
  *
  * <p>Class RegexPattern is not intended to be subclassed.</p>
  *
  * @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 method
<code>compile()</code>.
     *
     * @stable ICU 2.4
     */
    RegexPattern();

    /**
     * Copy Constructor.  Create a new RegexPattern object that is
equivalent
     *                    to the source object.
     * @param source the pattern object to be copied.
     * @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, <code>clone()</code> 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.
    *
    * <p>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.</p>
    *
    * <p>All pattern match mode flags are set to their default
values.</p>
    *
    * <p>Note that it is often more convenient to construct a
RegexMatcher directly
    *    from a pattern string rather than separately compiling the pattern
and
    *    then creating a RegexMatcher object from the pattern.</p>
    *
    * @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 * U_EXPORT2 compile( const UnicodeString
&regex,
        UParseError          &pe,
        UErrorCode           &status);

   /**
    * 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.
    *
    * <p>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.</p>
    *
    * <p>All pattern match mode flags are set to their default
values.</p>
    *
    * <p>Note that it is often more convenient to construct a
RegexMatcher directly
    *    from a pattern string rather than separately compiling the pattern
and
    *    then creating a RegexMatcher object from the pattern.</p>
    *
    * @param regex The regular expression to be compiled. Note, the text
referred
    *              to by this UText must not be deleted during the lifetime
of the
    *              RegexPattern object or any RegexMatcher object created
from it.
    * @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 4.6
    */
    static RegexPattern * U_EXPORT2 compile( UText *regex,
        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.
    *
    * <p>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.</p>
    *
    * <p>Note that it is often more convenient to construct a
RegexMatcher directly
    *    from a pattern string instead of than separately compiling the
pattern and
    *    then creating a RegexMatcher object from the pattern.</p>
    *
    * @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 numbers) 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 * U_EXPORT2 compile( const UnicodeString
&regex,
        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.
    *
    * <p>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.</p>
    *
    * <p>Note that it is often more convenient to construct a
RegexMatcher directly
    *    from a pattern string instead of than separately compiling the
pattern and
    *    then creating a RegexMatcher object from the pattern.</p>
    *
    * @param regex The regular expression to be compiled. Note, the text
referred
    *              to by this UText must not be deleted during the lifetime
of the
    *              RegexPattern object or any RegexMatcher object created
from it.
    * @param flags The match mode flags to be used.
    * @param pe    Receives the position (line and column numbers) 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 4.6
    */
    static RegexPattern * U_EXPORT2 compile( UText *regex,
        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.
    *
    * <p>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.</p>
    *
    * <p>Note that it is often more convenient to construct a
RegexMatcher directly
    *    from a pattern string instead of than separately compiling the
pattern and
    *    then creating a RegexMatcher object from the pattern.</p>
    *
    * @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.
    *
    * @stable ICU 2.6
    */
    static RegexPattern * U_EXPORT2 compile( const UnicodeString
&regex,
        uint32_t             flags,
        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.
    *
    * <p>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.</p>
    *
    * <p>Note that it is often more convenient to construct a
RegexMatcher directly
    *    from a pattern string instead of than separately compiling the
pattern and
    *    then creating a RegexMatcher object from the pattern.</p>
    *
    * @param regex The regular expression to be compiled. Note, the text
referred
    *              to by this UText must not be deleted during the lifetime
of the
    *              RegexPattern object or any RegexMatcher object created
from it.
    * @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.
    *
    * @stable ICU 4.6
    */
    static RegexPattern * U_EXPORT2 compile( UText *regex,
        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.
    * <p>
    * The matcher will retain a reference to the supplied input string, and
all regexp
    * pattern matching operations happen directly on this original string. 
It is
    * critical that the string not be altered or deleted before use by the
regular
    * expression operations is complete.
    *
    * @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;
        
private:
    /**
     * Cause a compilation error if an application accidentally attempts to
     *   create a matcher with a (UChar *) string as input rather than
     *   a UnicodeString.  Avoids a dangling reference to a temporary
string.
     * <p>
     * To efficiently work with UChar *strings, wrap the data in a
UnicodeString
     * using one of the aliasing constructors, such as
     * <code>UnicodeString(UBool isTerminated, const UChar *text,
int32_t textLength);</code>
     * or in a UText, using
     * <code>utext_openUChars(UText *ut, const UChar *text, int64_t
textLength, UErrorCode *status);</code>
     *
     * @internal
     */
    RegexMatcher *matcher(const UChar *input,
        UErrorCode          &status) const;
public:


   /**
    * 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.
    *
    * @stable ICU 2.6
    */
    virtual RegexMatcher *matcher(UErrorCode  &status) const;


   /**
    * Test whether a string matches a regular expression.  This convenience
function
    * both compiles the regular 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 RegexMatcher 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 U_EXPORT2 matches(const UnicodeString   &regex,
        const UnicodeString   &input,
              UParseError     &pe,
              UErrorCode      &status);

   /**
    * Test whether a string matches a regular expression.  This convenience
function
    * both compiles the regular 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 RegexMatcher 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 4.6
    */
    static UBool U_EXPORT2 matches(UText *regex,
        UText           *input,
        UParseError     &pe,
        UErrorCode      &status);

   /**
    * Returns the regular expression from which this pattern was compiled.
This method will work
    * even if the pattern was compiled from a UText.
    *
    * Note: If the pattern was originally compiled from a UText, and that
UText was modified,
    * the returned string may no longer reflect the RegexPattern object.
    * @stable ICU 2.4
    */
    virtual UnicodeString pattern() const;
    
    
   /**
    * Returns the regular expression from which this pattern was compiled.
This method will work
    * even if the pattern was compiled from a UnicodeString.
    *
    * Note: This is the original input, not a clone. If the pattern was
originally compiled from a
    * UText, and that UText was modified, the returned UText may no longer
reflect the RegexPattern
    * object.
    *
    * @stable ICU 4.6
    */
    virtual UText *patternText(UErrorCode      &status) const;


    /**
     * Split a string into fields.  Somewhat like split() from Perl or
Java.
     * Pattern matches identify delimiters that separate the input
     * into fields.  The input data between the delimiters becomes the
     * fields themselves.
     *
     * If the delimiter pattern includes capture groups, the captured text
will
     * also appear in the destination array of output strings, interspersed
     * with the fields.  This is similar to Perl, but differs from Java, 
     * which ignores the presence of capture groups in the pattern.
     * 
     * Trailing empty fields will always be returned, assuming sufficient
     * destination capacity.  This differs from the default behavior for
Java
     * and Perl where trailing empty fields are not returned.
     *
     * The number of strings produced by the split operation is returned.
     * This count includes the strings from capture groups in the delimiter
pattern.
     * This behavior differs from Java, which ignores capture groups.
     *
     * For the best performance on split() operations,
     * <code>RegexMatcher::split</code> is preferable 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;


    /**
     * Split a string into fields.  Somewhat like split() from Perl or
Java.
     * Pattern matches identify delimiters that separate the input
     * into fields.  The input data between the delimiters becomes the
     * fields themselves.
     *
     * If the delimiter pattern includes capture groups, the captured text
will
     * also appear in the destination array of output strings, interspersed
     * with the fields.  This is similar to Perl, but differs from Java, 
     * which ignores the presence of capture groups in the pattern.
     * 
     * Trailing empty fields will always be returned, assuming sufficient
     * destination capacity.  This differs from the default behavior for
Java
     * and Perl where trailing empty fields are not returned.
     *
     * The number of strings produced by the split operation is returned.
     * This count includes the strings from capture groups in the delimiter
pattern.
     * This behavior differs from Java, which ignores capture groups.
     *
     *  For the best performance on split() operations,
     *  <code>RegexMatcher::split</code> is preferable 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 mutable UText structs to receive the
results of the split.
     *                If a field is NULL, a new UText is allocated to
contain the results for
     *                that field. This new UText is not guaranteed to be
mutable.
     * @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 destination strings used.  
     *
     * @stable ICU 4.6
     */
    virtual int32_t  split(UText *input,
        UText            *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 U_EXPORT2 getStaticClassID();

private:
    //
    //  Implementation Data
    //
    UText          *fPattern;      // The original pattern string.
    UnicodeString  *fPatternString; // The original pattern UncodeString if
relevant
    uint32_t        fFlags;        // The flags used when compiling the
pattern.
                                   //
    UVector64       *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;
    UBool           fNeedsAltInput;

    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 U_EXPORT2 RegexPatternDump(const RegexPattern *);
#endif

};



/**
 *  class RegexMatcher bundles together a regular 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.
 *
 * <p>Class RegexMatcher is not intended to be subclassed.</p>
 *
 * @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.
      *  @stable ICU 2.6
      */
    RegexMatcher(const UnicodeString &regexp, 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 flags  Regular expression options, such as case insensitive
matching.
      *                @see UREGEX_CASE_INSENSITIVE
      *  @param status Any errors are reported by setting this UErrorCode
variable.
      *
      *  @stable ICU 4.6
      */
    RegexMatcher(UText *regexp, 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.
      * <p>
      * The matcher will retain a reference to the supplied input string,
and all regexp
      * pattern matching operations happen directly on the original string.
 It is
      * critical that the string not be altered or deleted before use by
the regular
      * expression operations is complete.
      *
      *  @param regexp The Regular Expression to be compiled.
      *  @param input  The string to match.  The matcher retains a
reference to the
      *                caller's string; mo copy is made.
      *  @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.
      *  @stable ICU 2.6
      */
    RegexMatcher(const UnicodeString &regexp, const UnicodeString
&input,
        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.
      * <p>
      * The matcher will make a shallow clone of the supplied input text,
and all regexp
      * pattern matching operations happen on this clone.  While read-only
operations on
      * the supplied text are permitted, it is critical that the underlying
string not be
      * altered or deleted before use by the regular expression operations
is complete.
      *
      *  @param regexp The Regular Expression to be compiled.
      *  @param input  The string to match.  The matcher retains a shallow
clone of the text.
      *  @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.
      *
      *  @stable ICU 4.6
      */
    RegexMatcher(UText *regexp, UText *input,
        uint32_t flags, UErrorCode &status);

private:
    /**
     * Cause a compilation error if an application accidentally attempts to
     *   create a matcher with a (UChar *) string as input rather than
     *   a UnicodeString.    Avoids a dangling reference to a temporary
string.
     * <p>
     * To efficiently work with UChar *strings, wrap the data in a
UnicodeString
     * using one of the aliasing constructors, such as
     * <code>UnicodeString(UBool isTerminated, const UChar *text,
int32_t textLength);</code>
     * or in a UText, using
     * <code>utext_openUChars(UText *ut, const UChar *text, int64_t
textLength, UErrorCode *status);</code>
     *
     * @internal
     */
    RegexMatcher(const UnicodeString &regexp, const UChar *input,
        uint32_t flags, UErrorCode &status);
public:


   /**
    *   Destructor.
    *
    *  @stable ICU 2.4
    */
    virtual ~RegexMatcher();


   /**
    *   Attempts to match the entire input region 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);


   /**
    *   Resets the matcher, then attempts to match the input beginning 
    *   at the specified startIndex, and extending to the end of the input.
    *   The input region is reset to include the entire input string.
    *   A successful match must extend to the end of the input.
    *    @param   startIndex The input string (native) index at which to
begin matching.
    *    @param   status     A reference to a UErrorCode to receive any
errors.
    *    @return TRUE if there is a match
    *    @stable ICU 2.8
    */
    virtual UBool matches(int64_t startIndex, UErrorCode &status);


   /**
    *   Attempts to match the input string, starting from the beginning of
the region,
    *   against the pattern.  Like the matches() method, this function 
    *   always starts at the beginning of the input region;
    *   unlike that function, it does not require that the entire region be
matched.
    *
    *   <p>If the match succeeds then more information can be
obtained via the <code>start()</code>,
    *     <code>end()</code>, and
<code>group()</code> functions.</p>
    *
    *    @param   status     A reference to a UErrorCode to receive any
errors.
    *    @return  TRUE if there is a match at the start of the input
string.
    *    @stable ICU 2.4
    */
    virtual UBool lookingAt(UErrorCode &status);


  /**
    *   Attempts to match the input string, starting from the specified
index, against the pattern.
    *   The match may be of any length, and is not required to extend to
the end
    *   of the input string.  Contrast with match().
    *
    *   <p>If the match succeeds then more information can be
obtained via the <code>start()</code>,
    *     <code>end()</code>, and
<code>group()</code> functions.</p>
    *
    *    @param   startIndex The input string (native) index at which to
begin matching.
    *    @param   status     A reference to a UErrorCode to receive any
errors.
    *    @return  TRUE if there is a match.
    *    @stable ICU 2.8
    */
    virtual UBool lookingAt(int64_t startIndex, UErrorCode &status);


   /**
    *  Find the next pattern match in the input string.
    *  The find begins searching the input at the location following the
end of
    *  the previous match, or at the start of the string if there is no
previous match.
    *  If a match is found, <code>start(), end()</code> and
<code>group()</code>
    *  will provide more information regarding the match.
    *  <p>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.</p>
    *  @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 (native) index 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(int64_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 a shallow clone of the entire live input string with the
UText current native index
    *   set to the beginning of the requested group.
    *
    *   @param   dest        The UText into which the input should be
cloned, or NULL to create a new UText
    *   @param   group_len   A reference to receive the length of the
desired capture group
    *   @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 dest if non-NULL, a shallow copy of the input text
otherwise
    *
    *   @stable ICU 4.6
    */
    virtual UText *group(UText *dest, int64_t &group_len, UErrorCode
&status) const; 

   /**
    *   Returns a shallow clone of the entire live input string with the
UText current native index
    *   set to the beginning of the requested group.
    *
    *   @param   groupNum   The capture group number.
    *   @param   dest        The UText into which the input should be
cloned, or NULL to create a new UText.
    *   @param   group_len   A reference to receive the length of the
desired capture group
    *   @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 dest if non-NULL, a shallow copy of the input text
otherwise
    *
    *   @stable ICU 4.6
    */
    virtual UText *group(int32_t groupNum, UText *dest, int64_t
&group_len, 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   dest        A mutable UText in which the matching text is
placed.
    *                        If NULL, a new UText will be created (which
may not be mutable).
    *   @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. If a
pre-allocated UText
    *            was provided, it will always be used and returned.
    *
    *   @internal ICU 4.4 technology preview
    */
    virtual UText *group(int32_t groupNum, UText *dest, UErrorCode
&status) 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 (native) 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
    *   during the previous match operation.
    *    @param   status      a reference to a UErrorCode to receive any
errors.
    *    @return              The (native) position in the input string of
the start of the last match.
    *   @stable ICU 4.6
    */
    virtual int64_t start64(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 (native) start position of substring matched by the
specified group.
    *    @stable ICU 2.4
    */
    virtual int32_t start(int32_t group, 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 (native) start position of substring matched by the
specified group.
    *    @stable ICU 4.6
    */
    virtual int64_t start64(int32_t group, UErrorCode &status) const;


   /**
    *    Returns the index in the input string of the first 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.
    *                        The index value returned is a native index,
corresponding to
    *                        code units for the underlying encoding type,
for example,
    *                        a byte index for UTF-8.
    *   @stable ICU 2.4
    */
    virtual int32_t end(UErrorCode &status) const;

   /**
    *    Returns the index in the input string of the first 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.
    *                        The index value returned is a native index,
corresponding to
    *                        code units for the underlying encoding type,
for example,
    *                        a byte index for UTF-8.
    *   @stable ICU 4.6
    */
    virtual int64_t end64(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 first character following the text
    *              captured by the specified group during the previous
match operation.
    *              Return -1 if the capture group exists in the pattern but
was not part of the match.
    *              The index value returned is a native index,
corresponding to
    *              code units for the underlying encoding type, for
example,
    *              a byte index for UTF8.
    *    @stable ICU 2.4
    */
    virtual int32_t end(int32_t group, 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 first character following the text
    *              captured by the specified group during the previous
match operation.
    *              Return -1 if the capture group exists in the pattern but
was not part of the match.
    *              The index value returned is a native index,
corresponding to
    *              code units for the underlying encoding type, for
example,
    *              a byte index for UTF8.
    *   @stable ICU 4.6
    */
    virtual int64_t end64(int32_t 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 (native) position in the input string.
    * <p>
    *   The matcher's region is reset to its default, which is the
entire
    *   input string.
    * <p>
    *   An alternative to this function is to set a match region
    *   beginning at the desired index.
    *
    *   @return this RegexMatcher.
    *   @stable ICU 2.8
    */
    virtual RegexMatcher &reset(int64_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.
    *   @param input The new string on which subsequent pattern matches
will operate.
    *                The matcher retains a reference to the callers string,
and operates
    *                directly on that.  Ownership of the string remains
with the caller.
    *                Because no copy of the string is made, it is essential
that the
    *                caller not delete the string until after regexp
operations on it
    *                are done.
    *                Note that while a reset on the matcher with an input
string that is then
    *                modified across/during matcher operations may be
supported currently for UnicodeString,
    *                this was not originally intended behavior, and support
for this is not guaranteed
    *                in upcoming versions of ICU.
    *   @return this RegexMatcher.
    *   @stable ICU 2.4
    */
    virtual RegexMatcher &reset(const UnicodeString &input);


   /**
    *   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.
    *   @param input The new string on which subsequent pattern matches
will operate.
    *                The matcher makes a shallow clone of the given text;
ownership of the
    *                original string remains with the caller. Because no
deep copy of the
    *                text is made, it is essential that the caller not
modify the string
    *                until after regexp operations on it are done.
    *   @return this RegexMatcher.
    *
    *   @stable ICU 4.6
    */
    virtual RegexMatcher &reset(UText *input);


  /**
    *  Set the subject text string upon which the regular expression is
looking for matches
    *  without changing any other aspect of the matching state.
    *  The new and previous text strings must have the same content.
    *
    *  This function is intended for use in environments where ICU is
operating on 
    *  strings that may move around in memory.  It provides a mechanism for
notifying
    *  ICU that the string has been relocated, and providing a new UText to
access the
    *  string in its new position.
    *
    *  Note that the regular expression implementation never copies the
underlying text
    *  of a string being matched, but always operates directly on the
original text 
    *  provided by the user. Refreshing simply drops the references to the
old text 
    *  and replaces them with references to the new.
    *
    *  Caution:  this function is normally used only by very specialized,
    *  system-level code.  One example use case is with garbage collection
that moves
    *  the text in memory.
    *
    * @param input      The new (moved) text string.
    * @param status     Receives errors detected by this function.
    *
    * @stable ICU 4.8 
    */
    virtual RegexMatcher &refreshInputText(UText *input, UErrorCode
&status);

private:
    /**
     * Cause a compilation error if an application accidentally attempts to
     *   reset a matcher with a (UChar *) string as input rather than
     *   a UnicodeString.    Avoids a dangling reference to a temporary
string.
     * <p>
     * To efficiently work with UChar *strings, wrap the data in a
UnicodeString
     * using one of the aliasing constructors, such as
     * <code>UnicodeString(UBool isTerminated, const UChar *text,
int32_t textLength);</code>
     * or in a UText, using
     * <code>utext_openUChars(UText *ut, const UChar *text, int64_t
textLength, UErrorCode *status);</code>
     *
     * @internal
     */
    RegexMatcher &reset(const UChar *input);
public:

   /**
    *   Returns the input string being matched.  Ownership of the string
belongs to
    *   the matcher; it should not be altered or deleted. This method will
work even if the input
    *   was originally supplied as a UText.
    *   @return the input string
    *   @stable ICU 2.4
    */
    virtual const UnicodeString &input() const;
    
   /**
    *   Returns the input string being matched.  This is the live input
text; it should not be
    *   altered or deleted. This method will work even if the input was
originally supplied as
    *   a UnicodeString.
    *   @return the input text
    *
    *   @stable ICU 4.6
    */
    virtual UText *inputText() const;
    
   /**
    *   Returns the input string being matched, either by copying it into
the provided
    *   UText parameter or by returning a shallow clone of the live input.
Note that copying
    *   the entire input may cause significant performance and memory
issues.
    *   @param dest The UText into which the input should be copied, or
NULL to create a new UText
    *   @param status error code
    *   @return dest if non-NULL, a shallow copy of the input text
otherwise
    *
    *   @stable ICU 4.6
    */
    virtual UText *getInput(UText *dest, UErrorCode &status) const;
    

   /** Sets the limits of this matcher's region.
     * The region is the part of the input string that will be searched to
find a match.
     * Invoking this method resets the matcher, and then sets the region to
start
     * at the index specified by the start parameter and end at the index
specified
     * by the end parameter.
     *
     * Depending on the transparency and anchoring being used (see
useTransparentBounds
     * and useAnchoringBounds), certain constructs such as anchors may
behave differently
     * at or around the boundaries of the region
     *
     * The function will fail if start is greater than limit, or if either
index
     *  is less than zero or greater than the length of the string being
matched.
     *
     * @param start  The (native) index to begin searches at.
     * @param limit  The index to end searches at (exclusive).
     * @param status A reference to a UErrorCode to receive any errors.
     * @stable ICU 4.0
     */
     virtual RegexMatcher &region(int64_t start, int64_t limit,
UErrorCode &status);

   /** 
     * Identical to region(start, limit, status) but also allows a start
position without
     *  resetting the region state.
     * @param regionStart The region start
     * @param regionLimit the limit of the region
     * @param startIndex  The (native) index within the region bounds at
which to begin searches.
     * @param status A reference to a UErrorCode to receive any errors.
     *                If startIndex is not within the specified region
bounds, 
     *                U_INDEX_OUTOFBOUNDS_ERROR is returned.
     * @stable ICU 4.6
     */
     virtual RegexMatcher &region(int64_t regionStart, int64_t
regionLimit, int64_t startIndex, UErrorCode &status);

   /**
     * Reports the start index of this matcher's region. The searches
this matcher
     * conducts are limited to finding matches within regionStart
(inclusive) and
     * regionEnd (exclusive).
     *
     * @return The starting (native) index of this matcher's region.
     * @stable ICU 4.0
     */
     virtual int32_t regionStart() const;

   /**
     * Reports the start index of this matcher's region. The searches
this matcher
     * conducts are limited to finding matches within regionStart
(inclusive) and
     * regionEnd (exclusive).
     *
     * @return The starting (native) index of this matcher's region.
     * @stable ICU 4.6
     */
     virtual int64_t regionStart64() const;


    /**
      * Reports the end (limit) index (exclusive) of this matcher's
region. The searches
      * this matcher conducts are limited to finding matches within
regionStart
      * (inclusive) and regionEnd (exclusive).
      *
      * @return The ending point (native) of this matcher's region.
      * @stable ICU 4.0
      */
      virtual int32_t regionEnd() const;

   /**
     * Reports the end (limit) index (exclusive) of this matcher's
region. The searches
     * this matcher conducts are limited to finding matches within
regionStart
     * (inclusive) and regionEnd (exclusive).
     *
     * @return The ending point (native) of this matcher's region.
     * @stable ICU 4.6
     */
      virtual int64_t regionEnd64() const;

    /**
      * Queries the transparency of region bounds for this matcher.
      * See useTransparentBounds for a description of transparent and
opaque bounds.
      * By default, a matcher uses opaque region boundaries.
      *
      * @return TRUE if this matcher is using opaque bounds, false if it is
not.
      * @stable ICU 4.0
      */
      virtual UBool hasTransparentBounds() const;

    /**
      * Sets the transparency of region bounds for this matcher.
      * Invoking this function with an argument of true will set this
matcher to use transparent bounds.
      * If the boolean argument is false, then opaque bounds will be used.
      *
      * Using transparent bounds, the boundaries of this matcher's
region are transparent
      * to lookahead, lookbehind, and boundary matching constructs. Those
constructs can
      * see text beyond the boundaries of the region while checking for a
match.
      *
      * With opaque bounds, no text outside of the matcher's region is
visible to lookahead,
      * lookbehind, and boundary matching constructs.
      *
      * By default, a matcher uses opaque bounds.
      *
      * @param   b TRUE for transparent bounds; FALSE for opaque bounds
      * @return  This Matcher;
      * @stable ICU 4.0
      **/
      virtual RegexMatcher &useTransparentBounds(UBool b);

     
    /**
      * Return true if this matcher is using anchoring bounds.
      * By default, matchers use anchoring region bounds.
      *
      * @return TRUE if this matcher is using anchoring bounds.
      * @stable ICU 4.0
      */    
      virtual UBool hasAnchoringBounds() const;


    /**
      * Set whether this matcher is using Anchoring Bounds for its region.
      * With anchoring bounds, pattern anchors such as ^ and $ will match
at the start
      * and end of the region.  Without Anchoring Bounds, anchors will only
match at
      * the positions they would in the complete text.
      *
      * Anchoring Bounds are the default for regions.
      *
      * @param b TRUE if to enable anchoring bounds; FALSE to disable them.
      * @return  This Matcher
      * @stable ICU 4.0
      */
      virtual RegexMatcher &useAnchoringBounds(UBool b);


    /**
      * Return TRUE if the most recent matching operation attempted to
access
      *  additional input beyond the available input text.
      *  In this case, additional input text could change the results of
the match.
      *
      *  hitEnd() is defined for both successful and unsuccessful matches.
      *  In either case hitEnd() will return TRUE if if the end of the text
was
      *  reached at any point during the matching process.
      *
      *  @return  TRUE if the most recent match hit the end of input
      *  @stable ICU 4.0
      */
      virtual UBool hitEnd() const;

    /**
      * Return TRUE the most recent match succeeded and additional input
could cause
      * it to fail. If this method returns false and a match was found,
then more input
      * might change the match but the match won't be lost. If a match
was not found,
      * then requireEnd has no meaning.
      *
      * @return TRUE if more input could cause the most recent match to no
longer match.
      * @stable ICU 4.0
      */
      virtual UBool requireEnd() 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 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   dest        a mutable UText in which the results are
placed.
    *                          If NULL, a new UText will be created (which
may not be mutable).
    *    @param   status      a reference to a UErrorCode to receive any
errors.
    *    @return              a string containing the results of the find
and replace.
    *                          If a pre-allocated UText was provided, it
will always be used and returned.
    *
    *    @stable ICU 4.6
    */
    virtual UText *replaceAll(UText *replacement, UText *dest, 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.
    *
    * <p>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.</p>
    *
    * <p>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.</p>
    *
    *    @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);
    

   /**
    * 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.
    *
    * <p>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.</p>
    *
    * <p>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.</p>
    *
    *    @param   replacement a string containing the replacement text.
    *    @param   dest        a mutable UText in which the results are
placed.
    *                          If NULL, a new UText will be created (which
may not be mutable).
    *    @param   status      a reference to a UErrorCode to receive any
errors.
    *    @return              a string containing the results of the find
and replace.
    *                          If a pre-allocated UText was provided, it
will always be used and returned.
    *
    *    @stable ICU 4.6
    */
    virtual UText *replaceFirst(UText *replacement, UText *dest, UErrorCode
&status);
    
    
   /**
    *   Implements a replace operation intended to be used as part of an
    *   incremental find-and-replace.
    *
    *   <p>The input string, starting from the end of the previous
replacement 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.</p>
    *
    *   <p>For simple, prepackaged, non-incremental find-and-replace
    *   operations, see replaceFirst() or replaceAll().</p>
    *
    *   @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);
    
    
   /**
    *   Implements a replace operation intended to be used as part of an
    *   incremental find-and-replace.
    *
    *   <p>The input string, starting from the end of the previous
replacement 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.</p>
    *
    *   <p>For simple, prepackaged, non-incremental find-and-replace
    *   operations, see replaceFirst() or replaceAll().</p>
    *
    *   @param   dest        A mutable UText to which the results of the
find-and-replace are appended.
    *                         Must not be NULL.
    *   @param   replacement A UText 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 4.6
    */
    virtual RegexMatcher &appendReplacement(UText *dest,
        UText *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
appendReplacement(),
    * to the destination string. <code>appendTail()</code> is
intended to be invoked after one
    * or more invocations of the
<code>RegexMatcher::appendReplacement()</code>.
    *
    *  @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);


   /**
    * As the final step in a find-and-replace operation, append the
remainder
    * of the input string, starting at the position following the last
appendReplacement(),
    * to the destination string. <code>appendTail()</code> is
intended to be invoked after one
    * or more invocations of the
<code>RegexMatcher::appendReplacement()</code>.
    *
    *  @param dest A mutable UText to which the results of the
find-and-replace are appended.
    *               Must not be NULL.
    *  @param status error cod
    *  @return  the destination string.
    *
    *  @stable ICU 4.6
    */
    virtual UText *appendTail(UText *dest, UErrorCode &status);


    /**
     * 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.
     * @stable ICU 2.6
     */
    virtual int32_t  split(const UnicodeString &input,
        UnicodeString    dest[],
        int32_t          destCapacity,
        UErrorCode       &status);


    /**
     * 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 mutable UText structs to receive the
results of the split.
     *                If a field is NULL, a new UText is allocated to
contain the results for
     *                that field. This new UText is not guaranteed to be
mutable.
     * @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 4.6
     */
    virtual int32_t  split(UText *input,
        UText           *dest[],
        int32_t          destCapacity,
        UErrorCode       &status);
    
  /**
    *   Set a processing time limit for match operations with this Matcher.
    *  
    *   Some patterns, when matching certain strings, can run in
exponential time.
    *   For practical purposes, the match operation may appear to be in an
    *   infinite loop.
    *   When a limit is set a match operation will fail with an error if
the
    *   limit is exceeded.
    *   <p>
    *   The units of the limit are steps of the match engine.
    *   Correspondence with actual processor time will depend on the speed
    *   of the processor and the details of the specific pattern, but will
    *   typically be on the order of milliseconds.
    *   <p>
    *   By default, the matching time is not limited.
    *   <p>
    *
    *   @param   limit       The limit value, or 0 for no limit.
    *   @param   status      A reference to a UErrorCode to receive any
errors.
    *   @stable ICU 4.0
    */
    virtual void setTimeLimit(int32_t limit, UErrorCode &status);

  /**
    * Get the time limit, if any, for match operations made with this
Matcher.
    *
    *   @return the maximum allowed time for a match, in units of
processing steps.
    *   @stable ICU 4.0
    */
    virtual int32_t getTimeLimit() const;

  /**
    *  Set the amount of heap storage available for use by the match
backtracking stack.
    *  The matcher is also reset, discarding any results from previous
matches.
    *  <p>
    *  ICU uses a backtracking regular expression engine, with the
backtrack stack
    *  maintained on the heap.  This function sets the limit to the amount
of memory
    *  that can be used  for this purpose.  A backtracking stack overflow
will
    *  result in an error from the match operation that caused it.
    *  <p>
    *  A limit is desirable because a malicious or poorly designed pattern
can use
    *  excessive memory, potentially crashing the process.  A limit is
enabled
    *  by default.
    *  <p>
    *  @param limit  The maximum size, in bytes, of the matching backtrack
stack.
    *                A value of zero means no limit.
    *                The limit must be greater or equal to zero.
    *
    *  @param status   A reference to a UErrorCode to receive any errors.
    *
    *  @stable ICU 4.0
    */
    virtual void setStackLimit(int32_t  limit, UErrorCode &status);
    
  /**
    *  Get the size of the heap storage available for use by the back
tracking stack.
    *
    *  @return  the maximum backtracking stack size, in bytes, or zero if
the
    *           stack size is unlimited.
    *  @stable ICU 4.0
    */
    virtual int32_t  getStackLimit() const;


  /**
    * Set a callback function for use with this Matcher.
    * During matching operations the function will be called periodically,
    * giving the application the opportunity to terminate a long-running
    * match.
    *
    *    @param   callback    A pointer to the user-supplied callback
function.
    *    @param   context     User context pointer.  The value supplied at
the
    *                         time the callback function is set will be
saved
    *                         and passed to the callback each time that it
is called.
    *    @param   status      A reference to a UErrorCode to receive any
errors.
    *  @stable ICU 4.0
    */
    virtual void setMatchCallback(URegexMatchCallback     *callback,
                                  const void              *context,
                                  UErrorCode              &status);


  /**
    *  Get the callback function for this URegularExpression.
    *
    *    @param   callback    Out parameter, receives a pointer to the
user-supplied 
    *                         callback function.
    *    @param   context     Out parameter, receives the user context
pointer that
    *                         was set when uregex_setMatchCallback() was
called.
    *    @param   status      A reference to a UErrorCode to receive any
errors.
    *    @stable ICU 4.0
    */
    virtual void getMatchCallback(URegexMatchCallback     *&callback,
                                  const void              *&context,
                                  UErrorCode              &status);


  /**
    * Set a progress callback function for use with find operations on this
Matcher.
    * During find operations, the callback will be invoked after each
return from a
    * match attempt, giving the application the opportunity to terminate a
long-running
    * find operation.
    *
    *    @param   callback    A pointer to the user-supplied callback
function.
    *    @param   context     User context pointer.  The value supplied at
the
    *                         time the callback function is set will be
saved
    *                         and passed to the callback each time that it
is called.
    *    @param   status      A reference to a UErrorCode to receive any
errors.
    *    @stable ICU 4.6
    */
    virtual void setFindProgressCallback(URegexFindProgressCallback     
*callback,
                                              const void                   
          *context,
                                              UErrorCode                   
          &status);


  /**
    *  Get the find progress callback function for this URegularExpression.
    *
    *    @param   callback    Out parameter, receives a pointer to the
user-supplied 
    *                         callback function.
    *    @param   context     Out parameter, receives the user context
pointer that
    *                         was set when uregex_setFindProgressCallback()
was called.
    *    @param   status      A reference to a UErrorCode to receive any
errors.
    *    @stable ICU 4.6
    */
    virtual void getFindProgressCallback(URegexFindProgressCallback     
*&callback,
                                              const void                   
  *&context,
                                              UErrorCode                   
  &status);

#ifndef U_HIDE_INTERNAL_API
   /**
     *   setTrace   Debug function, enable/disable tracing of the matching
engine.
     *              For internal ICU development use only.  DO NO USE!!!!
     *   @internal
     */
    void setTrace(UBool state);
#endif  /* U_HIDE_INTERNAL_API */

    /**
    * ICU "poor man's RTTI", returns a UClassID for this
class.
    *
    * @stable ICU 2.2
    */
    static UClassID U_EXPORT2 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);
    void init(UErrorCode &status);                      // Common
initialization
    void init2(UText *t, UErrorCode &e);  // Common initialization,
part 2.

    friend class RegexPattern;
    friend class RegexCImpl;
public:
#ifndef U_HIDE_INTERNAL_API
    /** @internal  */
    void resetPreserveRegion();  // Reset matcher state, but preserve any
region.
#endif  /* U_HIDE_INTERNAL_API */
private:

    //
    //  MatchAt   This is the internal interface to the match engine
itself.
    //            Match status comes back in matcher member variables.
    //
    void                 MatchAt(int64_t startIdx, UBool toEnd, UErrorCode
&status);
    inline void          backTrack(int64_t &inputIdx, int32_t
&patIdx);
    UBool                isWordBoundary(int64_t pos);         // perform
Perl-like  \b test
    UBool                isUWordBoundary(int64_t pos);        // perform
RBBI based \b test
    REStackFrame        *resetStack();
    inline REStackFrame *StateSave(REStackFrame *fp, int64_t savePatIdx,
UErrorCode &status);
    void                 IncrementTime(UErrorCode &status);
    UBool                ReportFindProgress(int64_t matchIndex, UErrorCode
&status);
    
    int64_t              appendGroup(int32_t groupNum, UText *dest,
UErrorCode &status) const;
    
    UBool                findUsingChunk();
    void                 MatchChunkAt(int32_t startIdx, UBool toEnd,
UErrorCode &status);
    UBool                isChunkWordBoundary(int32_t pos);

    const RegexPattern  *fPattern;
    RegexPattern        *fPatternOwned;    // Non-NULL if this matcher owns
the pattern, and
                                           //   should delete it when
through.

    const UnicodeString *fInput;           // The string being matched.
Only used for input()
    UText               *fInputText;       // The text being matched. Is
never NULL.
    UText               *fAltInputText;    // A shallow copy of the text
being matched.
                                           //   Only created if the pattern
contains backreferences.
    int64_t              fInputLength;     // Full length of the input
text.
    int32_t              fFrameSize;       // The size of a frame in the
backtrack stack.
    
    int64_t              fRegionStart;     // Start of the input region,
default = 0.
    int64_t              fRegionLimit;     // End of input region, default
to input.length.
    
    int64_t              fAnchorStart;     // Region bounds for anchoring
operations (^ or $).
    int64_t              fAnchorLimit;     //   See useAnchoringBounds
    
    int64_t              fLookStart;       // Region bounds for
look-ahead/behind and
    int64_t              fLookLimit;       //   and other boundary tests. 
See
                                           //   useTransparentBounds

    int64_t              fActiveStart;     // Currently active bounds for
matching.
    int64_t              fActiveLimit;     //   Usually is the same as
region, but
                                           //   is changed to
fLookStart/Limit when
                                           //   entering look around
regions.

    UBool                fTransparentBounds;  // True if using transparent
bounds.
    UBool                fAnchoringBounds; // True if using anchoring
bounds.

    UBool                fMatch;           // True if the last attempted
match was successful.
    int64_t              fMatchStart;      // Position of the start of the
most recent match
    int64_t              fMatchEnd;        // First position after the end
of the most recent match
                                           //   Zero if no previous match,
even when a region
                                           //   is active.
    int64_t              fLastMatchEnd;    // First position after the end
of the previous match,
                                           //   or -1 if there was no
previous match.
    int64_t              fAppendPosition;  // First position after the end
of the previous
                                           //   appendReplacement().  As
described by the
                                           //   JavaDoc for Java Matcher,
where it is called 
                                           //   "append position"
    UBool                fHitEnd;          // True if the last match
touched the end of input.
    UBool                fRequireEnd;      // True if the last match
required end-of-input
                                           //    (matched $ or Z)

    UVector64           *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.

    int64_t             *fData;            // Data area for use by the
compiled pattern.
    int64_t             fSmallData[8];     //   Use this for data if
it's enough.

    int32_t             fTimeLimit;        // Max time (in arbitrary steps)
to let the
                                           //   match engine run.  Zero for
unlimited.
    
    int32_t             fTime;             // Match time, accumulates while
matching.
    int32_t             fTickCounter;      // Low bits counter for time. 
Counts down StateSaves.
                                           //   Kept separately from fTime
to keep as much
                                           //   code as possible out of the
inline
                                           //   StateSave function.

    int32_t             fStackLimit;       // Maximum memory size to use
for the backtrack
                                           //   stack, in bytes.  Zero for
unlimited.

    URegexMatchCallback *fCallbackFn;       // Pointer to match progress
callback funct.
                                           //   NULL if there is no
callback.
    const void         *fCallbackContext;  // User Context ptr for callback
function.

    URegexFindProgressCallback  *fFindProgressCallbackFn;  // Pointer to
match progress callback funct.
                                                           //   NULL if
there is no callback.
    const void         *fFindProgressCallbackContext;      // User Context
ptr for callback function.


    UBool               fInputUniStrMaybeMutable;  // Set when fInputText
wraps a UnicodeString that may be mutable - compatibility.

    UBool               fTraceDebug;       // Set true for debug tracing of
match engine.

    UErrorCode          fDeferredStatus;   // Save error state that cannot
be immediately
                                           //   reported, or that
permanently disables this matcher.

    RuleBasedBreakIterator  *fWordBreakItr;
};

U_NAMESPACE_END
#endif  // UCONFIG_NO_REGULAR_EXPRESSIONS
#endif