+ * The algorithm implemented is a modified form of the Boyer Moore's search. + * For more information see + * + * "Efficient Text Searching in Java", published in Java Report + * in February, 1999, for further information on the algorithm. + *
+ * There are 2 match options for selection:
+ * This search has APIs similar to that of other text iteration mechanisms
+ * such as the break iterators in ubrk.h. Using these
+ * APIs, it is easy to scan through text looking for all occurances of
+ * a given pattern. This search iterator allows changing of direction by
+ * calling a reset followed by a next or previous.
+ * Though a direction change can occur without calling reset first,
+ * this operation comes with some speed penalty.
+ * Generally, match results in the forward direction will match the result
+ * matches in the backwards direction in the reverse order
+ *
+ * usearch.h provides APIs to specify the starting position
+ * within the text string to be searched, e.g. usearch_setOffset,
+ * usearch_preceding and usearch_following. Since the
+ * starting position will be set as it is specified, please take note that
+ * there are some dangerous positions which the search may render incorrect
+ * results:
+ *
+ * A breakiterator can be used if only matches at logical breaks are desired.
+ * Using a breakiterator will only give you results that exactly matches the
+ * boundaries given by the breakiterator. For instance the pattern "e" will
+ * not be found in the string "\u00e9" if a character break iterator is used.
+ *
+ * Options are provided to handle overlapping matches.
+ * E.g. In English, overlapping matches produces the result 0 and 2
+ * for the pattern "abab" in the text "ababab", where else mutually
+ * exclusive matches only produce the result of 0.
+ *
+ * Though collator attributes will be taken into consideration while
+ * performing matches, there are no APIs here for setting and getting the
+ * attributes. These attributes can be set by getting the collator
+ * from usearch_getCollator and using the APIs in ucol.h.
+ * Lastly to update String Search to the new collator attributes,
+ * usearch_reset() has to be called.
+ *
+ * Restriction:
+ * Example of use:
+* Use usearch_getMatchedLength to get the matched string length.
+* @param strsrch search iterator data struct
+* @return index to a substring within the text string that is being
+* searched.
+* @see #usearch_first
+* @see #usearch_next
+* @see #usearch_previous
+* @see #usearch_last
+* @see #USEARCH_DONE
+* @stable ICU 2.4
+*/
+U_STABLE int32_t U_EXPORT2 usearch_getMatchedStart(
+ const UStringSearch *strsrch);
+
+/**
+* Returns the length of text in the string which matches the search pattern.
+* This call returns a valid result only after a successful call to
+* usearch_first, usearch_next, usearch_previous,
+* or usearch_last.
+* Just after construction, or after a searching method returns
+* USEARCH_DONE, this method will return 0.
+* @param strsrch search iterator data struct
+* @return The length of the match in the string text, or 0 if there is no
+* match currently.
+* @see #usearch_first
+* @see #usearch_next
+* @see #usearch_previous
+* @see #usearch_last
+* @see #USEARCH_DONE
+* @stable ICU 2.4
+*/
+U_STABLE int32_t U_EXPORT2 usearch_getMatchedLength(
+ const UStringSearch *strsrch);
+
+/**
+* Returns the text that was matched by the most recent call to
+* usearch_first, usearch_next, usearch_previous,
+* or usearch_last.
+* If the iterator is not pointing at a valid match (e.g. just after
+* construction or after USEARCH_DONE has been returned, returns
+* an empty string. If result is not large enough to store the matched text,
+* result will be filled with the partial text and an U_BUFFER_OVERFLOW_ERROR
+* will be returned in status. result will be null-terminated whenever
+* possible. If the buffer fits the matched text exactly, a null-termination
+* is not possible, then a U_STRING_NOT_TERMINATED_ERROR set in status.
+* Pre-flighting can be either done with length = 0 or the API
+* usearch_getMatchLength.
+* @param strsrch search iterator data struct
+* @param result UChar buffer to store the matched string
+* @param resultCapacity length of the result buffer
+* @param status error returned if result is not large enough
+* @return exact length of the matched text, not counting the null-termination
+* @see #usearch_first
+* @see #usearch_next
+* @see #usearch_previous
+* @see #usearch_last
+* @see #USEARCH_DONE
+* @stable ICU 2.4
+*/
+U_STABLE int32_t U_EXPORT2 usearch_getMatchedText(const UStringSearch *strsrch,
+ UChar *result,
+ int32_t resultCapacity,
+ UErrorCode *status);
+
+#if !UCONFIG_NO_BREAK_ITERATION
+
+/**
+* Set the BreakIterator that will be used to restrict the points at which
+* matches are detected.
+* @param strsrch search iterator data struct
+* @param breakiter A BreakIterator that will be used to restrict the points
+* at which matches are detected. If a match is found, but
+* the match's start or end index is not a boundary as
+* determined by the BreakIterator, the match will
+* be rejected and another will be searched for.
+* If this parameter is NULL, no break detection is
+* attempted.
+* @param status for errors if it occurs
+* @see #usearch_getBreakIterator
+* @stable ICU 2.4
+*/
+U_STABLE void U_EXPORT2 usearch_setBreakIterator(UStringSearch *strsrch,
+ UBreakIterator *breakiter,
+ UErrorCode *status);
+
+/**
+* Returns the BreakIterator that is used to restrict the points at which
+* matches are detected. This will be the same object that was passed to the
+* constructor or to usearch_setBreakIterator. Note that
+* NULL
+* is a legal value; it means that break detection should not be attempted.
+* @param strsrch search iterator data struct
+* @return break iterator used
+* @see #usearch_setBreakIterator
+* @stable ICU 2.4
+*/
+U_STABLE const UBreakIterator * U_EXPORT2 usearch_getBreakIterator(
+ const UStringSearch *strsrch);
+
+#endif
+
+/**
+* Set the string text to be searched. Text iteration will hence begin at the
+* start of the text string. This method is useful if you want to re-use an
+* iterator to search for the same pattern within a different body of text.
+* @param strsrch search iterator data struct
+* @param text new string to look for match
+* @param textlength length of the new string, -1 for null-termination
+* @param status for errors if it occurs. If text is NULL, or textlength is 0
+* then an U_ILLEGAL_ARGUMENT_ERROR is returned with no change
+* done to strsrch.
+* @see #usearch_getText
+* @stable ICU 2.4
+*/
+U_STABLE void U_EXPORT2 usearch_setText( UStringSearch *strsrch,
+ const UChar *text,
+ int32_t textlength,
+ UErrorCode *status);
+
+/**
+* Return the string text to be searched.
+* @param strsrch search iterator data struct
+* @param length returned string text length
+* @return string text
+* @see #usearch_setText
+* @stable ICU 2.4
+*/
+U_STABLE const UChar * U_EXPORT2 usearch_getText(const UStringSearch *strsrch,
+ int32_t *length);
+
+/**
+* Gets the collator used for the language rules.
+*
+* Deleting the returned UCollator before calling
+* usearch_close would cause the string search to fail.
+* usearch_close will delete the collator if this search owns it.
+* @param strsrch search iterator data struct
+* @return collator
+* @stable ICU 2.4
+*/
+U_STABLE UCollator * U_EXPORT2 usearch_getCollator(
+ const UStringSearch *strsrch);
+
+/**
+* Sets the collator used for the language rules. User retains the ownership
+* of this collator, thus the responsibility of deletion lies with the user.
+* This method causes internal data such as Boyer-Moore shift tables to
+* be recalculated, but the iterator's position is unchanged.
+* @param strsrch search iterator data struct
+* @param collator to be used
+* @param status for errors if it occurs
+* @stable ICU 2.4
+*/
+U_STABLE void U_EXPORT2 usearch_setCollator( UStringSearch *strsrch,
+ const UCollator *collator,
+ UErrorCode *status);
+
+/**
+* Sets the pattern used for matching.
+* Internal data like the Boyer Moore table will be recalculated, but the
+* iterator's position is unchanged.
+* @param strsrch search iterator data struct
+* @param pattern string
+* @param patternlength pattern length, -1 for null-terminated string
+* @param status for errors if it occurs. If text is NULL, or textlength is 0
+* then an U_ILLEGAL_ARGUMENT_ERROR is returned with no change
+* done to strsrch.
+* @stable ICU 2.4
+*/
+U_STABLE void U_EXPORT2 usearch_setPattern( UStringSearch *strsrch,
+ const UChar *pattern,
+ int32_t patternlength,
+ UErrorCode *status);
+
+/**
+* Gets the search pattern
+* @param strsrch search iterator data struct
+* @param length return length of the pattern, -1 indicates that the pattern
+* is null-terminated
+* @return pattern string
+* @stable ICU 2.4
+*/
+U_STABLE const UChar * U_EXPORT2 usearch_getPattern(
+ const UStringSearch *strsrch,
+ int32_t *length);
+
+/* methods ------------------------------------------------------------- */
+
+/**
+* Returns the first index at which the string text matches the search
+* pattern.
+* The iterator is adjusted so that its current index (as returned by
+* usearch_getOffset) is the match position if one was found.
+* If a match is not found, USEARCH_DONE will be returned and
+* the iterator will be adjusted to the index USEARCH_DONE.
+* @param strsrch search iterator data struct
+* @param status for errors if it occurs
+* @return The character index of the first match, or
+* USEARCH_DONE if there are no matches.
+* @see #usearch_getOffset
+* @see #USEARCH_DONE
+* @stable ICU 2.4
+*/
+U_STABLE int32_t U_EXPORT2 usearch_first(UStringSearch *strsrch,
+ UErrorCode *status);
+
+/**
+* Returns the first index greater than position at which the string
+* text
+* matches the search pattern. The iterator is adjusted so that its current
+* index (as returned by usearch_getOffset) is the match position if
+* one was found.
+* If a match is not found, USEARCH_DONE will be returned and
+* the iterator will be adjusted to the index USEARCH_DONE
+*
+* Search positions that may render incorrect results are highlighted in the
+* header comments. If position is less than or greater than the text range
+* for searching, an U_INDEX_OUTOFBOUNDS_ERROR will be returned
+* @param strsrch search iterator data struct
+* @param position to start the search at
+* @param status for errors if it occurs
+* @return The character index of the first match following pos,
+* or USEARCH_DONE if there are no matches.
+* @see #usearch_getOffset
+* @see #USEARCH_DONE
+* @stable ICU 2.4
+*/
+U_STABLE int32_t U_EXPORT2 usearch_following(UStringSearch *strsrch,
+ int32_t position,
+ UErrorCode *status);
+
+/**
+* Returns the last index in the target text at which it matches the search
+* pattern. The iterator is adjusted so that its current
+* index (as returned by usearch_getOffset) is the match position if
+* one was found.
+* If a match is not found, USEARCH_DONE will be returned and
+* the iterator will be adjusted to the index USEARCH_DONE.
+* @param strsrch search iterator data struct
+* @param status for errors if it occurs
+* @return The index of the first match, or USEARCH_DONE if there
+* are no matches.
+* @see #usearch_getOffset
+* @see #USEARCH_DONE
+* @stable ICU 2.4
+*/
+U_STABLE int32_t U_EXPORT2 usearch_last(UStringSearch *strsrch,
+ UErrorCode *status);
+
+/**
+* Returns the first index less than position at which the string text
+* matches the search pattern. The iterator is adjusted so that its current
+* index (as returned by usearch_getOffset) is the match position if
+* one was found.
+* If a match is not found, USEARCH_DONE will be returned and
+* the iterator will be adjusted to the index USEARCH_DONE
+*
+* Search positions that may render incorrect results are highlighted in the
+* header comments. If position is less than or greater than the text range
+* for searching, an U_INDEX_OUTOFBOUNDS_ERROR will be returned
+* @param strsrch search iterator data struct
+* @param position index position the search is to begin at
+* @param status for errors if it occurs
+* @return The character index of the first match preceding pos,
+* or USEARCH_DONE if there are no matches.
+* @see #usearch_getOffset
+* @see #USEARCH_DONE
+* @stable ICU 2.4
+*/
+U_STABLE int32_t U_EXPORT2 usearch_preceding(UStringSearch *strsrch,
+ int32_t position,
+ UErrorCode *status);
+
+/**
+* Returns the index of the next point at which the string text matches the
+* search pattern, starting from the current position.
+* The iterator is adjusted so that its current
+* index (as returned by usearch_getOffset) is the match position if
+* one was found.
+* If a match is not found, USEARCH_DONE will be returned and
+* the iterator will be adjusted to the index USEARCH_DONE
+* @param strsrch search iterator data struct
+* @param status for errors if it occurs
+* @return The index of the next match after the current position, or
+* USEARCH_DONE if there are no more matches.
+* @see #usearch_first
+* @see #usearch_getOffset
+* @see #USEARCH_DONE
+* @stable ICU 2.4
+*/
+U_STABLE int32_t U_EXPORT2 usearch_next(UStringSearch *strsrch,
+ UErrorCode *status);
+
+/**
+* Returns the index of the previous point at which the string text matches
+* the search pattern, starting at the current position.
+* The iterator is adjusted so that its current
+* index (as returned by usearch_getOffset) is the match position if
+* one was found.
+* If a match is not found, USEARCH_DONE will be returned and
+* the iterator will be adjusted to the index USEARCH_DONE
+* @param strsrch search iterator data struct
+* @param status for errors if it occurs
+* @return The index of the previous match before the current position,
+* or USEARCH_DONE if there are no more matches.
+* @see #usearch_last
+* @see #usearch_getOffset
+* @see #USEARCH_DONE
+* @stable ICU 2.4
+*/
+U_STABLE int32_t U_EXPORT2 usearch_previous(UStringSearch *strsrch,
+ UErrorCode *status);
+
+/**
+* Reset the iteration.
+* Search will begin at the start of the text string if a forward iteration
+* is initiated before a backwards iteration. Otherwise if a backwards
+* iteration is initiated before a forwards iteration, the search will begin
+* at the end of the text string.
+* @param strsrch search iterator data struct
+* @see #usearch_first
+* @stable ICU 2.4
+*/
+U_STABLE void U_EXPORT2 usearch_reset(UStringSearch *strsrch);
+
+#endif /* #if !UCONFIG_NO_COLLATION */
+
+#endif
+ * Let S' be the sub-string of a text string S between the offsets start and
+ * end
+ * A pattern string P matches a text string S at the offsets
+ * option 1. Some canonical equivalent of P matches some canonical equivalent
+ * of S'
+ * option 2. P matches S' and if P starts or ends with a combining mark,
+ * there exists no non-ignorable combining mark before or after S'
+ * in S respectively.
+ *
+ * Option 2. will be the default.
+ *
+ *
+ *
+ * Currently there are no composite characters that consists of a
+ * character with combining class > 0 before a character with combining
+ * class == 0. However, if such a character exists in the future, the
+ * search mechanism does not guarantee the results for option 1.
+ *
+ *
+ *
+ * @stable ICU 2.4
+ */
+
+/**
+* DONE is returned by previous() and next() after all valid matches have
+* been returned, and by first() and last() if there are no matches at all.
+* @stable ICU 2.4
+*/
+#define USEARCH_DONE -1
+
+/**
+* Data structure for searching
+* @stable ICU 2.4
+*/
+struct UStringSearch;
+/**
+* Data structure for searching
+* @stable ICU 2.4
+*/
+typedef struct UStringSearch UStringSearch;
+
+/**
+* @stable ICU 2.4
+*/
+typedef enum {
+ /** Option for overlapping matches */
+ USEARCH_OVERLAP,
+ /**
+ Option for canonical matches. option 1 in header documentation.
+ The default value will be USEARCH_OFF
+ */
+ USEARCH_CANONICAL_MATCH,
+ USEARCH_ATTRIBUTE_COUNT
+} USearchAttribute;
+
+/**
+* @stable ICU 2.4
+*/
+typedef enum {
+ /** default value for any USearchAttribute */
+ USEARCH_DEFAULT = -1,
+ /** value for USEARCH_OVERLAP and USEARCH_CANONICAL_MATCH */
+ USEARCH_OFF,
+ /** value for USEARCH_OVERLAP and USEARCH_CANONICAL_MATCH */
+ USEARCH_ON,
+ USEARCH_ATTRIBUTE_VALUE_COUNT
+} USearchAttributeValue;
+
+/* open and close ------------------------------------------------------ */
+
+/**
+* Creating a search iterator data struct using the argument locale language
+* rule set. A collator will be created in the process, which will be owned by
+* this search and will be deleted in usearch_close.
+* @param pattern for matching
+* @param patternlength length of the pattern, -1 for null-termination
+* @param text text string
+* @param textlength length of the text string, -1 for null-termination
+* @param locale name of locale for the rules to be used
+* @param breakiter A BreakIterator that will be used to restrict the points
+* at which matches are detected. If a match is found, but
+* the match's start or end index is not a boundary as
+* determined by the BreakIterator, the match will
+* be rejected and another will be searched for.
+* If this parameter is NULL, no break detection is
+* attempted.
+* @param status for errors if it occurs. If pattern or text is NULL, or if
+* patternlength or textlength is 0 then an
+* U_ILLEGAL_ARGUMENT_ERROR is returned.
+* @return search iterator data structure, or NULL if there is an error.
+* @stable ICU 2.4
+*/
+U_STABLE UStringSearch * U_EXPORT2 usearch_open(const UChar *pattern,
+ int32_t patternlength,
+ const UChar *text,
+ int32_t textlength,
+ const char *locale,
+ UBreakIterator *breakiter,
+ UErrorCode *status);
+
+/**
+* Creating a search iterator data struct using the argument collator language
+* rule set. Note, user retains the ownership of this collator, thus the
+* responsibility of deletion lies with the user.
+* NOTE: string search cannot be instantiated from a collator that has
+* collate digits as numbers (CODAN) turned on.
+* @param pattern for matching
+* @param patternlength length of the pattern, -1 for null-termination
+* @param text text string
+* @param textlength length of the text string, -1 for null-termination
+* @param collator used for the language rules
+* @param breakiter A BreakIterator that will be used to restrict the points
+* at which matches are detected. If a match is found, but
+* the match's start or end index is not a boundary as
+* determined by the BreakIterator, the match will
+* be rejected and another will be searched for.
+* If this parameter is NULL, no break detection is
+* attempted.
+* @param status for errors if it occurs. If collator, pattern or text is NULL,
+* or if patternlength or textlength is 0 then an
+* U_ILLEGAL_ARGUMENT_ERROR is returned.
+* @return search iterator data structure, or NULL if there is an error.
+* @stable ICU 2.4
+*/
+U_STABLE UStringSearch * U_EXPORT2 usearch_openFromCollator(
+ const UChar *pattern,
+ int32_t patternlength,
+ const UChar *text,
+ int32_t textlength,
+ const UCollator *collator,
+ UBreakIterator *breakiter,
+ UErrorCode *status);
+
+/**
+* Destroying and cleaning up the search iterator data struct.
+* If a collator is created in usearch_open, it will be destroyed here.
+* @param searchiter data struct to clean up
+* @stable ICU 2.4
+*/
+U_STABLE void U_EXPORT2 usearch_close(UStringSearch *searchiter);
+
+/* get and set methods -------------------------------------------------- */
+
+/**
+* Sets the current position in the text string which the next search will
+* start from. Clears previous states.
+* This method takes the argument index and sets the position in the text
+* string accordingly without checking if the index is pointing to a
+* valid starting point to begin searching.
+* Search positions that may render incorrect results are highlighted in the
+* header comments
+* @param strsrch search iterator data struct
+* @param position position to start next search from. If position is less
+* than or greater than the text range for searching,
+* an U_INDEX_OUTOFBOUNDS_ERROR will be returned
+* @param status error status if any.
+* @stable ICU 2.4
+*/
+U_STABLE void U_EXPORT2 usearch_setOffset(UStringSearch *strsrch,
+ int32_t position,
+ UErrorCode *status);
+
+/**
+* Return the current index in the string text being searched.
+* If the iteration has gone past the end of the text (or past the beginning
+* for a backwards search), USEARCH_DONE is returned.
+* @param strsrch search iterator data struct
+* @see #USEARCH_DONE
+* @stable ICU 2.4
+*/
+U_STABLE int32_t U_EXPORT2 usearch_getOffset(const UStringSearch *strsrch);
+
+/**
+* Sets the text searching attributes located in the enum USearchAttribute
+* with values from the enum USearchAttributeValue.
+* USEARCH_DEFAULT can be used for all attributes for resetting.
+* @param strsrch search iterator data struct
+* @param attribute text attribute to be set
+* @param value text attribute value
+* @param status for errors if it occurs
+* @see #usearch_getAttribute
+* @stable ICU 2.4
+*/
+U_STABLE void U_EXPORT2 usearch_setAttribute(UStringSearch *strsrch,
+ USearchAttribute attribute,
+ USearchAttributeValue value,
+ UErrorCode *status);
+
+/**
+* Gets the text searching attributes.
+* @param strsrch search iterator data struct
+* @param attribute text attribute to be retrieve
+* @return text attribute value
+* @see #usearch_setAttribute
+* @stable ICU 2.4
+*/
+U_STABLE USearchAttributeValue U_EXPORT2 usearch_getAttribute(
+ const UStringSearch *strsrch,
+ USearchAttribute attribute);
+
+/**
+* Returns the index to the match in the text string that was searched.
+* This call returns a valid result only after a successful call to
+* usearch_first, usearch_next, usearch_previous,
+* or usearch_last.
+* Just after construction, or after a searching method returns
+* USEARCH_DONE, this method will return USEARCH_DONE.
+*
+ * char *tgtstr = "The quick brown fox jumped over the lazy fox";
+ * char *patstr = "fox";
+ * UChar target[64];
+ * UChar pattern[16];
+ * UErrorCode status = U_ZERO_ERROR;
+ * u_uastrcpy(target, tgtstr);
+ * u_uastrcpy(pattern, patstr);
+ *
+ * UStringSearch *search = usearch_open(pattern, -1, target, -1, "en_US",
+ * &status);
+ * if (U_SUCCESS(status)) {
+ * for (int pos = usearch_first(search, &status);
+ * pos != USEARCH_DONE;
+ * pos = usearch_next(search, &status)) {
+ * printf("Found match at %d pos, length is %d\n", pos,
+ * usearch_getMatchLength(search));
+ * }
+ * }
+ *