icuSources/common/unicode/unimatch.h

   1 // © 2016 and later: Unicode, Inc. and others.
   2 // License & terms of use: http://www.unicode.org/copyright.html
   3 /*
   4 * Copyright (C) 2001-2005, International Business Machines Corporation and others. All Rights Reserved.
   5 **********************************************************************
   6 *   Date        Name        Description
   7 *   07/18/01    aliu        Creation.
   8 **********************************************************************
   9 */
  10 #ifndef UNIMATCH_H
  11 #define UNIMATCH_H
  12
  13 #include "unicode/utypes.h"
  14
  15 /**
  16  * \file
  17  * \brief C++ API: Unicode Matcher
  18  */
  19
  20
  21 #if U_SHOW_CPLUSPLUS_API
  22 U_NAMESPACE_BEGIN
  23
  24 class Replaceable;
  25 class UnicodeString;
  26 class UnicodeSet;
  27
  28 /**
  29  * Constants returned by <code>UnicodeMatcher::matches()</code>
  30  * indicating the degree of match.
  31  * @stable ICU 2.4
  32  */
  33 enum UMatchDegree {
  34     /**
  35      * Constant returned by <code>matches()</code> indicating a
  36      * mismatch between the text and this matcher.  The text contains
  37      * a character which does not match, or the text does not contain
  38      * all desired characters for a non-incremental match.
  39      * @stable ICU 2.4
  40      */
  41     U_MISMATCH,
  42
  43     /**
  44      * Constant returned by <code>matches()</code> indicating a
  45      * partial match between the text and this matcher.  This value is
  46      * only returned for incremental match operations.  All characters
  47      * of the text match, but more characters are required for a
  48      * complete match.  Alternatively, for variable-length matchers,
  49      * all characters of the text match, and if more characters were
  50      * supplied at limit, they might also match.
  51      * @stable ICU 2.4
  52      */
  53     U_PARTIAL_MATCH,
  54
  55     /**
  56      * Constant returned by <code>matches()</code> indicating a
  57      * complete match between the text and this matcher.  For an
  58      * incremental variable-length match, this value is returned if
  59      * the given text matches, and it is known that additional
  60      * characters would not alter the extent of the match.
  61      * @stable ICU 2.4
  62      */
  63     U_MATCH
  64 };
  65
  66 /**
  67  * <code>UnicodeMatcher</code> defines a protocol for objects that can
  68  * match a range of characters in a Replaceable string.
  69  * @stable ICU 2.4
  70  */
  71 class U_COMMON_API UnicodeMatcher /* not : public UObject because this is an interface/mixin class */ {
  72
  73 public:
  74     /**
  75      * Destructor.
  76      * @stable ICU 2.4
  77      */
  78     virtual ~UnicodeMatcher();
  79
  80     /**
  81      * Return a UMatchDegree value indicating the degree of match for
  82      * the given text at the given offset.  Zero, one, or more
  83      * characters may be matched.
  84      *
  85      * Matching in the forward direction is indicated by limit >
  86      * offset.  Characters from offset forwards to limit-1 will be
  87      * considered for matching.
  88      *
  89      * Matching in the reverse direction is indicated by limit <
  90      * offset.  Characters from offset backwards to limit+1 will be
  91      * considered for matching.
  92      *
  93      * If limit == offset then the only match possible is a zero
  94      * character match (which subclasses may implement if desired).
  95      *
  96      * As a side effect, advance the offset parameter to the limit of
  97      * the matched substring.  In the forward direction, this will be
  98      * the index of the last matched character plus one.  In the
  99      * reverse direction, this will be the index of the last matched
 100      * character minus one.
 101      *
 102      * <p>Note:  This method is not const because some classes may
 103      * modify their state as the result of a match.
 104      *
 105      * @param text the text to be matched
 106      * @param offset on input, the index into text at which to begin
 107      * matching.  On output, the limit of the matched text.  The
 108      * number of matched characters is the output value of offset
 109      * minus the input value.  Offset should always point to the
 110      * HIGH SURROGATE (leading code unit) of a pair of surrogates,
 111      * both on entry and upon return.
 112      * @param limit the limit index of text to be matched.  Greater
 113      * than offset for a forward direction match, less than offset for
 114      * a backward direction match.  The last character to be
 115      * considered for matching will be text.charAt(limit-1) in the
 116      * forward direction or text.charAt(limit+1) in the backward
 117      * direction.
 118      * @param incremental if TRUE, then assume further characters may
 119      * be inserted at limit and check for partial matching.  Otherwise
 120      * assume the text as given is complete.
 121      * @return a match degree value indicating a full match, a partial
 122      * match, or a mismatch.  If incremental is FALSE then
 123      * U_PARTIAL_MATCH should never be returned.
 124      * @stable ICU 2.4
 125      */
 126     virtual UMatchDegree matches(const Replaceable& text,
 127                                  int32_t& offset,
 128                                  int32_t limit,
 129                                  UBool incremental) = 0;
 130
 131     /**
 132      * Returns a string representation of this matcher.  If the result of
 133      * calling this function is passed to the appropriate parser, it
 134      * will produce another matcher that is equal to this one.
 135      * @param result the string to receive the pattern.  Previous
 136      * contents will be deleted.
 137      * @param escapeUnprintable if TRUE then convert unprintable
 138      * character to their hex escape representations, \\uxxxx or
 139      * \\Uxxxxxxxx.  Unprintable characters are those other than
 140      * U+000A, U+0020..U+007E.
 141      * @stable ICU 2.4
 142      */
 143     virtual UnicodeString& toPattern(UnicodeString& result,
 144                                      UBool escapeUnprintable = FALSE) const = 0;
 145
 146     /**
 147      * Returns TRUE if this matcher will match a character c, where c
 148      * & 0xFF == v, at offset, in the forward direction (with limit >
 149      * offset).  This is used by <tt>RuleBasedTransliterator</tt> for
 150      * indexing.
 151      * @stable ICU 2.4
 152      */
 153     virtual UBool matchesIndexValue(uint8_t v) const = 0;
 154
 155     /**
 156      * Union the set of all characters that may be matched by this object
 157      * into the given set.
 158      * @param toUnionTo the set into which to union the source characters
 159      * @stable ICU 2.4
 160      */
 161     virtual void addMatchSetTo(UnicodeSet& toUnionTo) const = 0;
 162 };
 163
 164 U_NAMESPACE_END
 165 #endif // U_SHOW_CPLUSPLUS_API
 166
 167 #endif