icuSources/common/unicode/unimatch.h

   1 /*
   2 * Copyright (C) 2001-2004, International Business Machines Corporation and others. All Rights Reserved.
   3 **********************************************************************
   4 *   Date        Name        Description
   5 *   07/18/01    aliu        Creation.
   6 **********************************************************************
   7 */
   8 #ifndef UNIMATCH_H
   9 #define UNIMATCH_H
  10
  11 #include "unicode/utypes.h"
  12
  13 U_NAMESPACE_BEGIN
  14
  15 class Replaceable;
  16 class UnicodeString;
  17 class UnicodeSet;
  18
  19 /**
  20  * Constants returned by <code>UnicodeMatcher::matches()</code>
  21  * indicating the degree of match.
  22  * @stable ICU 2.4
  23  */
  24 enum UMatchDegree {
  25     /**
  26      * Constant returned by <code>matches()</code> indicating a
  27      * mismatch between the text and this matcher.  The text contains
  28      * a character which does not match, or the text does not contain
  29      * all desired characters for a non-incremental match.
  30      * @stable ICU 2.4
  31      */
  32     U_MISMATCH,
  33
  34     /**
  35      * Constant returned by <code>matches()</code> indicating a
  36      * partial match between the text and this matcher.  This value is
  37      * only returned for incremental match operations.  All characters
  38      * of the text match, but more characters are required for a
  39      * complete match.  Alternatively, for variable-length matchers,
  40      * all characters of the text match, and if more characters were
  41      * supplied at limit, they might also match.
  42      * @stable ICU 2.4
  43      */
  44     U_PARTIAL_MATCH,
  45
  46     /**
  47      * Constant returned by <code>matches()</code> indicating a
  48      * complete match between the text and this matcher.  For an
  49      * incremental variable-length match, this value is returned if
  50      * the given text matches, and it is known that additional
  51      * characters would not alter the extent of the match.
  52      * @stable ICU 2.4
  53      */
  54     U_MATCH
  55 };
  56
  57 /**
  58  * <code>UnicodeMatcher</code> defines a protocol for objects that can
  59  * match a range of characters in a Replaceable string.
  60  * @stable ICU 2.4
  61  */
  62 class U_COMMON_API UnicodeMatcher /* not : public UObject because this is an interface/mixin class */ {
  63
  64 public:
  65     /**
  66      * Destructor.
  67      * @stable ICU 2.4
  68      */
  69     virtual ~UnicodeMatcher();
  70
  71     /**
  72      * Return a UMatchDegree value indicating the degree of match for
  73      * the given text at the given offset.  Zero, one, or more
  74      * characters may be matched.
  75      *
  76      * Matching in the forward direction is indicated by limit >
  77      * offset.  Characters from offset forwards to limit-1 will be
  78      * considered for matching.
  79      *
  80      * Matching in the reverse direction is indicated by limit <
  81      * offset.  Characters from offset backwards to limit+1 will be
  82      * considered for matching.
  83      *
  84      * If limit == offset then the only match possible is a zero
  85      * character match (which subclasses may implement if desired).
  86      *
  87      * As a side effect, advance the offset parameter to the limit of
  88      * the matched substring.  In the forward direction, this will be
  89      * the index of the last matched character plus one.  In the
  90      * reverse direction, this will be the index of the last matched
  91      * character minus one.
  92      *
  93      * <p>Note:  This method is not const because some classes may
  94      * modify their state as the result of a match.
  95      *
  96      * @param text the text to be matched
  97      * @param offset on input, the index into text at which to begin
  98      * matching.  On output, the limit of the matched text.  The
  99      * number of matched characters is the output value of offset
 100      * minus the input value.  Offset should always point to the
 101      * HIGH SURROGATE (leading code unit) of a pair of surrogates,
 102      * both on entry and upon return.
 103      * @param limit the limit index of text to be matched.  Greater
 104      * than offset for a forward direction match, less than offset for
 105      * a backward direction match.  The last character to be
 106      * considered for matching will be text.charAt(limit-1) in the
 107      * forward direction or text.charAt(limit+1) in the backward
 108      * direction.
 109      * @param incremental if TRUE, then assume further characters may
 110      * be inserted at limit and check for partial matching.  Otherwise
 111      * assume the text as given is complete.
 112      * @return a match degree value indicating a full match, a partial
 113      * match, or a mismatch.  If incremental is FALSE then
 114      * U_PARTIAL_MATCH should never be returned.
 115      * @stable ICU 2.4
 116      */
 117     virtual UMatchDegree matches(const Replaceable& text,
 118                                  int32_t& offset,
 119                                  int32_t limit,
 120                                  UBool incremental) = 0;
 121
 122     /**
 123      * Returns a string representation of this matcher.  If the result of
 124      * calling this function is passed to the appropriate parser, it
 125      * will produce another matcher that is equal to this one.
 126      * @param result the string to receive the pattern.  Previous
 127      * contents will be deleted.
 128      * @param escapeUnprintable if TRUE then convert unprintable
 129      * character to their hex escape representations, \\uxxxx or
 130      * \\Uxxxxxxxx.  Unprintable characters are those other than
 131      * U+000A, U+0020..U+007E.
 132      * @stable ICU 2.4
 133      */
 134     virtual UnicodeString& toPattern(UnicodeString& result,
 135                                      UBool escapeUnprintable = FALSE) const = 0;
 136
 137     /**
 138      * Returns TRUE if this matcher will match a character c, where c
 139      * & 0xFF == v, at offset, in the forward direction (with limit >
 140      * offset).  This is used by <tt>RuleBasedTransliterator</tt> for
 141      * indexing.
 142      * @stable ICU 2.4
 143      */
 144     virtual UBool matchesIndexValue(uint8_t v) const = 0;
 145
 146     /**
 147      * Union the set of all characters that may be matched by this object
 148      * into the given set.
 149      * @param toUnionTo the set into which to union the source characters
 150      * @stable ICU 2.4
 151      */
 152     virtual void addMatchSetTo(UnicodeSet& toUnionTo) const = 0;
 153 };
 154
 155 U_NAMESPACE_END
 156
 157 #endif