icuSources/common/unicode/unimatch.h

   1 /*
   2 * Copyright (C) 2001-2005, 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 /**
  14  * \file
  15  * \brief C++ API: Unicode Matcher
  16  */
  17
  18
  19 U_NAMESPACE_BEGIN
  20
  21 class Replaceable;
  22 class UnicodeString;
  23 class UnicodeSet;
  24
  25 /**
  26  * Constants returned by <code>UnicodeMatcher::matches()</code>
  27  * indicating the degree of match.
  28  * @stable ICU 2.4
  29  */
  30 enum UMatchDegree {
  31     /**
  32      * Constant returned by <code>matches()</code> indicating a
  33      * mismatch between the text and this matcher.  The text contains
  34      * a character which does not match, or the text does not contain
  35      * all desired characters for a non-incremental match.
  36      * @stable ICU 2.4
  37      */
  38     U_MISMATCH,
  39
  40     /**
  41      * Constant returned by <code>matches()</code> indicating a
  42      * partial match between the text and this matcher.  This value is
  43      * only returned for incremental match operations.  All characters
  44      * of the text match, but more characters are required for a
  45      * complete match.  Alternatively, for variable-length matchers,
  46      * all characters of the text match, and if more characters were
  47      * supplied at limit, they might also match.
  48      * @stable ICU 2.4
  49      */
  50     U_PARTIAL_MATCH,
  51
  52     /**
  53      * Constant returned by <code>matches()</code> indicating a
  54      * complete match between the text and this matcher.  For an
  55      * incremental variable-length match, this value is returned if
  56      * the given text matches, and it is known that additional
  57      * characters would not alter the extent of the match.
  58      * @stable ICU 2.4
  59      */
  60     U_MATCH
  61 };
  62
  63 /**
  64  * <code>UnicodeMatcher</code> defines a protocol for objects that can
  65  * match a range of characters in a Replaceable string.
  66  * @stable ICU 2.4
  67  */
  68 class U_COMMON_API UnicodeMatcher /* not : public UObject because this is an interface/mixin class */ {
  69
  70 public:
  71     /**
  72      * Destructor.
  73      * @stable ICU 2.4
  74      */
  75     virtual ~UnicodeMatcher();
  76
  77     /**
  78      * Return a UMatchDegree value indicating the degree of match for
  79      * the given text at the given offset.  Zero, one, or more
  80      * characters may be matched.
  81      *
  82      * Matching in the forward direction is indicated by limit >
  83      * offset.  Characters from offset forwards to limit-1 will be
  84      * considered for matching.
  85      *
  86      * Matching in the reverse direction is indicated by limit <
  87      * offset.  Characters from offset backwards to limit+1 will be
  88      * considered for matching.
  89      *
  90      * If limit == offset then the only match possible is a zero
  91      * character match (which subclasses may implement if desired).
  92      *
  93      * As a side effect, advance the offset parameter to the limit of
  94      * the matched substring.  In the forward direction, this will be
  95      * the index of the last matched character plus one.  In the
  96      * reverse direction, this will be the index of the last matched
  97      * character minus one.
  98      *
  99      * <p>Note:  This method is not const because some classes may
 100      * modify their state as the result of a match.
 101      *
 102      * @param text the text to be matched
 103      * @param offset on input, the index into text at which to begin
 104      * matching.  On output, the limit of the matched text.  The
 105      * number of matched characters is the output value of offset
 106      * minus the input value.  Offset should always point to the
 107      * HIGH SURROGATE (leading code unit) of a pair of surrogates,
 108      * both on entry and upon return.
 109      * @param limit the limit index of text to be matched.  Greater
 110      * than offset for a forward direction match, less than offset for
 111      * a backward direction match.  The last character to be
 112      * considered for matching will be text.charAt(limit-1) in the
 113      * forward direction or text.charAt(limit+1) in the backward
 114      * direction.
 115      * @param incremental if TRUE, then assume further characters may
 116      * be inserted at limit and check for partial matching.  Otherwise
 117      * assume the text as given is complete.
 118      * @return a match degree value indicating a full match, a partial
 119      * match, or a mismatch.  If incremental is FALSE then
 120      * U_PARTIAL_MATCH should never be returned.
 121      * @stable ICU 2.4
 122      */
 123     virtual UMatchDegree matches(const Replaceable& text,
 124                                  int32_t& offset,
 125                                  int32_t limit,
 126                                  UBool incremental) = 0;
 127
 128     /**
 129      * Returns a string representation of this matcher.  If the result of
 130      * calling this function is passed to the appropriate parser, it
 131      * will produce another matcher that is equal to this one.
 132      * @param result the string to receive the pattern.  Previous
 133      * contents will be deleted.
 134      * @param escapeUnprintable if TRUE then convert unprintable
 135      * character to their hex escape representations, \\uxxxx or
 136      * \\Uxxxxxxxx.  Unprintable characters are those other than
 137      * U+000A, U+0020..U+007E.
 138      * @stable ICU 2.4
 139      */
 140     virtual UnicodeString& toPattern(UnicodeString& result,
 141                                      UBool escapeUnprintable = FALSE) const = 0;
 142
 143     /**
 144      * Returns TRUE if this matcher will match a character c, where c
 145      * & 0xFF == v, at offset, in the forward direction (with limit >
 146      * offset).  This is used by <tt>RuleBasedTransliterator</tt> for
 147      * indexing.
 148      * @stable ICU 2.4
 149      */
 150     virtual UBool matchesIndexValue(uint8_t v) const = 0;
 151
 152     /**
 153      * Union the set of all characters that may be matched by this object
 154      * into the given set.
 155      * @param toUnionTo the set into which to union the source characters
 156      * @stable ICU 2.4
 157      */
 158     virtual void addMatchSetTo(UnicodeSet& toUnionTo) const = 0;
 159 };
 160
 161 U_NAMESPACE_END
 162
 163 #endif