UnicodeMatcher::matches()
* indicating the degree of match.
* @stable ICU 2.4
*/
enum UMatchDegree {
/**
* Constant returned by matches() indicating a
* mismatch between the text and this matcher. The text contains
* a character which does not match, or the text does not contain
* all desired characters for a non-incremental match.
* @stable ICU 2.4
*/
U_MISMATCH,
/**
* Constant returned by matches() indicating a
* partial match between the text and this matcher. This value is
* only returned for incremental match operations. All characters
* of the text match, but more characters are required for a
* complete match. Alternatively, for variable-length matchers,
* all characters of the text match, and if more characters were
* supplied at limit, they might also match.
* @stable ICU 2.4
*/
U_PARTIAL_MATCH,
/**
* Constant returned by matches() indicating a
* complete match between the text and this matcher. For an
* incremental variable-length match, this value is returned if
* the given text matches, and it is known that additional
* characters would not alter the extent of the match.
* @stable ICU 2.4
*/
U_MATCH
};
/**
* UnicodeMatcher defines a protocol for objects that can
* match a range of characters in a Replaceable string.
* @stable ICU 2.4
*/
class U_COMMON_API UnicodeMatcher /* not : public UObject because this is an interface/mixin class */ {
public:
/**
* Destructor.
* @stable ICU 2.4
*/
virtual ~UnicodeMatcher();
/**
* Return a UMatchDegree value indicating the degree of match for
* the given text at the given offset. Zero, one, or more
* characters may be matched.
*
* Matching in the forward direction is indicated by limit >
* offset. Characters from offset forwards to limit-1 will be
* considered for matching.
*
* Matching in the reverse direction is indicated by limit <
* offset. Characters from offset backwards to limit+1 will be
* considered for matching.
*
* If limit == offset then the only match possible is a zero
* character match (which subclasses may implement if desired).
*
* As a side effect, advance the offset parameter to the limit of
* the matched substring. In the forward direction, this will be
* the index of the last matched character plus one. In the
* reverse direction, this will be the index of the last matched
* character minus one.
*
* Note: This method is not const because some classes may * modify their state as the result of a match. * * @param text the text to be matched * @param offset on input, the index into text at which to begin * matching. On output, the limit of the matched text. The * number of matched characters is the output value of offset * minus the input value. Offset should always point to the * HIGH SURROGATE (leading code unit) of a pair of surrogates, * both on entry and upon return. * @param limit the limit index of text to be matched. Greater * than offset for a forward direction match, less than offset for * a backward direction match. The last character to be * considered for matching will be text.charAt(limit-1) in the * forward direction or text.charAt(limit+1) in the backward * direction. * @param incremental if TRUE, then assume further characters may * be inserted at limit and check for partial matching. Otherwise * assume the text as given is complete. * @return a match degree value indicating a full match, a partial * match, or a mismatch. If incremental is FALSE then * U_PARTIAL_MATCH should never be returned. * @stable ICU 2.4 */ virtual UMatchDegree matches(const Replaceable& text, int32_t& offset, int32_t limit, UBool incremental) = 0; /** * Returns a string representation of this matcher. If the result of * calling this function is passed to the appropriate parser, it * will produce another matcher that is equal to this one. * @param result the string to receive the pattern. Previous * contents will be deleted. * @param escapeUnprintable if TRUE then convert unprintable * character to their hex escape representations, \\uxxxx or * \\Uxxxxxxxx. Unprintable characters are those other than * U+000A, U+0020..U+007E. * @stable ICU 2.4 */ virtual UnicodeString& toPattern(UnicodeString& result, UBool escapeUnprintable = FALSE) const = 0; /** * Returns TRUE if this matcher will match a character c, where c * & 0xFF == v, at offset, in the forward direction (with limit > * offset). This is used by RuleBasedTransliterator for * indexing. * @stable ICU 2.4 */ virtual UBool matchesIndexValue(uint8_t v) const = 0; /** * Union the set of all characters that may be matched by this object * into the given set. * @param toUnionTo the set into which to union the source characters * @stable ICU 2.4 */ virtual void addMatchSetTo(UnicodeSet& toUnionTo) const = 0; }; U_NAMESPACE_END #endif