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 // © 2016 and later: Unicode, Inc. and others.
 // License & terms of use: http://www.unicode.org/copyright.html
 /*
 **********************************************************************
 *   Copyright (C) 2001-2011,2014 IBM and others. All rights reserved.
 **********************************************************************
 *   Date        Name        Description
 *  06/28/2001   synwee      Creation.
 **********************************************************************
 */
 #ifndef USEARCH_H
 #define USEARCH_H
 
 #include "unicode/utypes.h"
 
 #if !UCONFIG_NO_COLLATION && !UCONFIG_NO_BREAK_ITERATION
 
 #include "unicode/ucol.h"
 #include "unicode/ucoleitr.h"
 #include "unicode/ubrk.h"
 
 #if U_SHOW_CPLUSPLUS_API
 #include "unicode/localpointer.h"
 #endif   // U_SHOW_CPLUSPLUS_API
 
 /**
  * \file
  * \brief C API: StringSearch
  *
  * C APIs for an engine that provides language-sensitive text searching based 
  * on the comparison rules defined in a <code>UCollator</code> data struct,
  * see <code>ucol.h</code>. This ensures that language eccentricity can be 
  * handled, e.g. for the German collator, characters &szlig; and SS will be matched 
  * if case is chosen to be ignored. 
  * See the <a href="https://htmlpreview.github.io/?https://github.com/unicode-org/icu-docs/blob/main/design/collation/ICU_collation_design.htm">
  * "ICU Collation Design Document"</a> for more information.
  * <p> 
  * As of ICU4C 4.0 / ICU4J 53, the implementation uses a linear search. In previous versions,
  * a modified form of the Boyer-Moore searching algorithm was used. For more information
  * on the modified Boyer-Moore algorithm see
  * <a href="http://icu-project.org/docs/papers/efficient_text_searching_in_java.html">
  * "Efficient Text Searching in Java"</a>, published in <i>Java Report</i> 
  * in February, 1999.
  * <p>
  * There are 2 match options for selection:<br>
  * Let S' be the sub-string of a text string S between the offsets start and 
  * end <start, end>.
  * <br>
  * A pattern string P matches a text string S at the offsets <start, end> 
  * if
  * <pre> 
  * 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. 
  * </pre>
  * Option 2. will be the default.
  * <p>
  * This search has APIs similar to that of other text iteration mechanisms 
  * such as the break iterators in <code>ubrk.h</code>. Using these 
  * APIs, it is easy to scan through text looking for all occurrences of 
  * a given pattern. This search iterator allows changing of direction by 
  * calling a <code>reset</code> followed by a <code>next</code> or <code>previous</code>. 
  * Though a direction change can occur without calling <code>reset</code> 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
  * <p>
  * <code>usearch.h</code> provides APIs to specify the starting position 
  * within the text string to be searched, e.g. <code>usearch_setOffset</code>,
  * <code>usearch_preceding</code> and <code>usearch_following</code>. 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:
  * <ul>
  * <li> The midst of a substring that requires normalization.
  * <li> If the following match is to be found, the position should not be the
  *      second character which requires to be swapped with the preceding 
  *      character. Vice versa, if the preceding match is to be found, 
  *      position to search from should not be the first character which 
  *      requires to be swapped with the next character. E.g certain Thai and
  *      Lao characters require swapping.
  * <li> If a following pattern match is to be found, any position within a 
  *      contracting sequence except the first will fail. Vice versa if a 
  *      preceding pattern match is to be found, a invalid starting point 
  *      would be any character within a contracting sequence except the last.
  * </ul>
  * <p>
  * 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.
  * <p>
  * 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.
  * <p>
  * Options are also provided to implement "asymmetric search" as described in
  * <a href="http://www.unicode.org/reports/tr10/#Asymmetric_Search">
  * UTS #10 Unicode Collation Algorithm</a>, specifically the USearchAttribute
  * USEARCH_ELEMENT_COMPARISON and its values.
  * <p>
  * 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 <code>usearch_getCollator</code> and using the APIs in <code>ucol.h</code>.
  * Lastly to update String Search to the new collator attributes, 
  * usearch_reset() has to be called.
  * <p> 
  * Restriction: <br>
  * 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.
  * 
  * <p>
  * Example of use:<br>
  * <pre><code>
  * 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", 
  *                                  NULL, &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_getMatchedLength(search));
  *     }
  * }
  *
  * usearch_close(search);
  * </code></pre>
  * @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
      * @stable ICU 2.4
      */
     USEARCH_OVERLAP = 0,
 #ifndef U_HIDE_DEPRECATED_API
     /** 
      * Option for canonical matches; option 1 in header documentation.
      * The default value will be USEARCH_OFF.
      * Note: Setting this option to USEARCH_ON currently has no effect on
      * search behavior, and this option is deprecated. Instead, to control
      * canonical match behavior, you must set UCOL_NORMALIZATION_MODE
      * appropriately (to UCOL_OFF or UCOL_ON) in the UCollator used by
      * the UStringSearch object.
      * @see usearch_openFromCollator 
      * @see usearch_getCollator
      * @see usearch_setCollator
      * @see ucol_getAttribute
      * @deprecated ICU 53
      */
     USEARCH_CANONICAL_MATCH = 1,
 #endif  /* U_HIDE_DEPRECATED_API */
     /** 
      * Option to control how collation elements are compared.
      * The default value will be USEARCH_STANDARD_ELEMENT_COMPARISON.
      * @stable ICU 4.4
      */
     USEARCH_ELEMENT_COMPARISON = 2,
 
 #ifndef U_HIDE_DEPRECATED_API
     /**
      * One more than the highest normal USearchAttribute value.
      * @deprecated ICU 58 The numeric value may change over time, see ICU ticket #12420.
      */
     USEARCH_ATTRIBUTE_COUNT = 3
 #endif  /* U_HIDE_DEPRECATED_API */
 } USearchAttribute;
 
 /**
 * @stable ICU 2.4
 */
 typedef enum {
     /** 
      * Default value for any USearchAttribute
      * @stable ICU 2.4
      */
     USEARCH_DEFAULT = -1,
     /**
      * Value for USEARCH_OVERLAP and USEARCH_CANONICAL_MATCH
      * @stable ICU 2.4
      */
     USEARCH_OFF, 
     /**
      * Value for USEARCH_OVERLAP and USEARCH_CANONICAL_MATCH
      * @stable ICU 2.4
      */
     USEARCH_ON,
     /** 
      * Value (default) for USEARCH_ELEMENT_COMPARISON;
      * standard collation element comparison at the specified collator
      * strength.
      * @stable ICU 4.4
      */
     USEARCH_STANDARD_ELEMENT_COMPARISON,
     /** 
      * Value for USEARCH_ELEMENT_COMPARISON;
      * collation element comparison is modified to effectively provide
      * behavior between the specified strength and strength - 1. Collation
      * elements in the pattern that have the base weight for the specified
      * strength are treated as "wildcards" that match an element with any
      * other weight at that collation level in the searched text. For
      * example, with a secondary-strength English collator, a plain 'e' in
      * the pattern will match a plain e or an e with any diacritic in the
      * searched text, but an e with diacritic in the pattern will only
      * match an e with the same diacritic in the searched text.
      *
      * This supports "asymmetric search" as described in
      * <a href="http://www.unicode.org/reports/tr10/#Asymmetric_Search">
      * UTS #10 Unicode Collation Algorithm</a>.
      *
      * @stable ICU 4.4
      */
     USEARCH_PATTERN_BASE_WEIGHT_IS_WILDCARD,
     /** 
      * Value for USEARCH_ELEMENT_COMPARISON.
      * collation element comparison is modified to effectively provide
      * behavior between the specified strength and strength - 1. Collation
      * elements in either the pattern or the searched text that have the
      * base weight for the specified strength are treated as "wildcards"
      * that match an element with any other weight at that collation level.
      * For example, with a secondary-strength English collator, a plain 'e'
      * in the pattern will match a plain e or an e with any diacritic in the
      * searched text, but an e with diacritic in the pattern will only
      * match an e with the same diacritic or a plain e in the searched text.
      *
      * This option is similar to "asymmetric search" as described in
      * [UTS #10 Unicode Collation Algorithm](http://www.unicode.org/reports/tr10/#Asymmetric_Search),
      * but also allows unmarked characters in the searched text to match
      * marked or unmarked versions of that character in the pattern.
      *
      * @stable ICU 4.4
      */
     USEARCH_ANY_BASE_WEIGHT_IS_WILDCARD,
 
 #ifndef U_HIDE_DEPRECATED_API
     /**
      * One more than the highest normal USearchAttributeValue value.
      * @deprecated ICU 58 The numeric value may change over time, see ICU ticket #12420.
      */
     USEARCH_ATTRIBUTE_VALUE_COUNT
 #endif  /* U_HIDE_DEPRECATED_API */
 } USearchAttributeValue;
 
 /* open and close ------------------------------------------------------ */
 
 /**
 * Creates a String 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 String Search and will be deleted in <code>usearch_close</code>.
 *
 * The UStringSearch retains a pointer to both the pattern and text strings.
 * The caller must not modify or delete them while using the UStringSearch.
 *
 * @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 <code>BreakIterator</code>, the match will 
 *                  be rejected and another will be searched for. 
 *                  If this parameter is <code>NULL</code>, 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_CAPI UStringSearch * U_EXPORT2 usearch_open(const UChar    *pattern,
                                               int32_t         patternlength,
                                         const UChar          *text,
                                               int32_t         textlength,
                                         const char           *locale,
                                               UBreakIterator *breakiter,
                                               UErrorCode     *status);
 
 /**
 * Creates a String 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 (UCOL_NUMERIC_COLLATION).
 *
 * The UStringSearch retains a pointer to both the pattern and text strings.
 * The caller must not modify or delete them while using the UStringSearch.
 *
 * @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 <code>BreakIterator</code>, the match will
 *                  be rejected and another will be searched for.
 *                  If this parameter is <code>NULL</code>, 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_CAPI UStringSearch * U_EXPORT2 usearch_openFromCollator(
                                          const UChar          *pattern,
                                                int32_t         patternlength,
                                          const UChar          *text,
                                                int32_t         textlength,
                                          const UCollator      *collator,
                                                UBreakIterator *breakiter,
                                                UErrorCode     *status);
 
 /**
  * Destroys and cleans up the String Search iterator data struct.
  * If a collator was created in <code>usearch_open</code>, then it will be destroyed here.
  * @param searchiter The UStringSearch to clean up
  * @stable ICU 2.4
  */
 U_CAPI void U_EXPORT2 usearch_close(UStringSearch *searchiter);
 
 #if U_SHOW_CPLUSPLUS_API
 
 U_NAMESPACE_BEGIN
 
 /**
  * \class LocalUStringSearchPointer
  * "Smart pointer" class, closes a UStringSearch via usearch_close().
  * For most methods see the LocalPointerBase base class.
  *
  * @see LocalPointerBase
  * @see LocalPointer
  * @stable ICU 4.4
  */
 U_DEFINE_LOCAL_OPEN_POINTER(LocalUStringSearchPointer, UStringSearch, usearch_close);
 
 U_NAMESPACE_END
 
 #endif
 
 /* 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_CAPI 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), <code>USEARCH_DONE</code> is returned.
 * @param strsrch search iterator data struct
 * @see #USEARCH_DONE
 * @stable ICU 2.4
 */
 U_CAPI 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.
 * <code>USEARCH_DEFAULT</code> 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_CAPI 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_CAPI 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 
 * <code>usearch_first</code>, <code>usearch_next</code>, <code>usearch_previous</code>, 
 * or <code>usearch_last</code>.
 * Just after construction, or after a searching method returns 
 * <code>USEARCH_DONE</code>, this method will return <code>USEARCH_DONE</code>.
 * <p>
 * Use <code>usearch_getMatchedLength</code> 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_CAPI 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 
 * <code>usearch_first</code>, <code>usearch_next</code>, <code>usearch_previous</code>, 
 * or <code>usearch_last</code>.
 * Just after construction, or after a searching method returns 
 * <code>USEARCH_DONE</code>, 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_CAPI int32_t U_EXPORT2 usearch_getMatchedLength(
                                                const UStringSearch *strsrch);
 
 /**
 * Returns the text that was matched by the most recent call to 
 * <code>usearch_first</code>, <code>usearch_next</code>, <code>usearch_previous</code>, 
 * or <code>usearch_last</code>.
 * If the iterator is not pointing at a valid match (e.g. just after 
 * construction or after <code>USEARCH_DONE</code> 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 
 * <code>usearch_getMatchedLength</code>.
 * @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_CAPI 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 <code>BreakIterator</code>, the match will 
 *                  be rejected and another will be searched for. 
 *                  If this parameter is <code>NULL</code>, no break detection is 
 *                  attempted.
 * @param status for errors if it occurs
 * @see #usearch_getBreakIterator
 * @stable ICU 2.4
 */
 U_CAPI 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 <code>usearch_setBreakIterator</code>. Note that 
 * <code>NULL</code> 
 * 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_CAPI 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.
 *
 * The UStringSearch retains a pointer to the text string. The caller must not
 * modify or delete the string while using the UStringSearch.
 *
 * @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_CAPI 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_CAPI const UChar * U_EXPORT2 usearch_getText(const UStringSearch *strsrch, 
                                                int32_t       *length);
 
 /**
 * Gets the collator used for the language rules. 
 * <p>
 * Deleting the returned <code>UCollator</code> before calling 
 * <code>usearch_close</code> would cause the string search to fail.
 * <code>usearch_close</code> will delete the collator if this search owns it.
 * @param strsrch search iterator data struct
 * @return collator
 * @stable ICU 2.4
 */
 U_CAPI 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 the pattern collation elements
 * and 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_CAPI void U_EXPORT2 usearch_setCollator(      UStringSearch *strsrch, 
                                           const UCollator     *collator,
                                                 UErrorCode    *status);
 
 /**
 * Sets the pattern used for matching.
 * Internal data like the pattern collation elements will be recalculated, but the 
 * iterator's position is unchanged.
 *
 * The UStringSearch retains a pointer to the pattern string. The caller must not
 * modify or delete the string while using the UStringSearch.
 *
 * @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_CAPI 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_CAPI 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 
 * <code>usearch_getOffset</code>) is the match position if one was found.
 * If a match is not found, <code>USEARCH_DONE</code> will be returned and
 * the iterator will be adjusted to the index <code>USEARCH_DONE</code>.
 * @param strsrch search iterator data struct
 * @param status for errors if it occurs
 * @return The character index of the first match, or 
 * <code>USEARCH_DONE</code> if there are no matches.
 * @see #usearch_getOffset
 * @see #USEARCH_DONE
 * @stable ICU 2.4
 */
 U_CAPI int32_t U_EXPORT2 usearch_first(UStringSearch *strsrch, 
                                            UErrorCode    *status);
 
 /**
 * Returns the first index equal or greater than <code>position</code> at which
 * the string text
 * matches the search pattern. The iterator is adjusted so that its current 
 * index (as returned by <code>usearch_getOffset</code>) is the match position if 
 * one was found.
 * If a match is not found, <code>USEARCH_DONE</code> will be returned and
 * the iterator will be adjusted to the index <code>USEARCH_DONE</code>
 * <p>
 * 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 <code>pos</code>,
 *         or <code>USEARCH_DONE</code> if there are no matches.
 * @see #usearch_getOffset
 * @see #USEARCH_DONE
 * @stable ICU 2.4
 */
 U_CAPI 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 <code>usearch_getOffset</code>) is the match position if 
 * one was found.
 * If a match is not found, <code>USEARCH_DONE</code> will be returned and
 * the iterator will be adjusted to the index <code>USEARCH_DONE</code>.
 * @param strsrch search iterator data struct
 * @param status for errors if it occurs
 * @return The index of the first match, or <code>USEARCH_DONE</code> if there 
 *         are no matches.
 * @see #usearch_getOffset
 * @see #USEARCH_DONE
 * @stable ICU 2.4
 */
 U_CAPI int32_t U_EXPORT2 usearch_last(UStringSearch *strsrch, 
                                           UErrorCode    *status);
 
 /**
 * Returns the first index less than <code>position</code> at which the string text 
 * matches the search pattern. The iterator is adjusted so that its current 
 * index (as returned by <code>usearch_getOffset</code>) is the match position if 
 * one was found.
 * If a match is not found, <code>USEARCH_DONE</code> will be returned and
 * the iterator will be adjusted to the index <code>USEARCH_DONE</code>
 * <p>
 * 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.
 * <p>
 * When <code>USEARCH_OVERLAP</code> option is off, the last index of the
 * result match is always less than <code>position</code>.
 * When <code>USERARCH_OVERLAP</code> is on, the result match may span across
 * <code>position</code>.
 * @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 <code>pos</code>,
 *         or <code>USEARCH_DONE</code> if there are no matches.
 * @see #usearch_getOffset
 * @see #USEARCH_DONE
 * @stable ICU 2.4
 */
 U_CAPI 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 <code>usearch_getOffset</code>) is the match position if 
 * one was found.
 * If a match is not found, <code>USEARCH_DONE</code> will be returned and
 * the iterator will be adjusted to the index <code>USEARCH_DONE</code>
 * @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 
 *         <code>USEARCH_DONE</code> if there are no more matches.
 * @see #usearch_first
 * @see #usearch_getOffset
 * @see #USEARCH_DONE
 * @stable ICU 2.4
 */
 U_CAPI 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 <code>usearch_getOffset</code>) is the match position if 
 * one was found.
 * If a match is not found, <code>USEARCH_DONE</code> will be returned and
 * the iterator will be adjusted to the index <code>USEARCH_DONE</code>
 * @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 <code>USEARCH_DONE</code> if there are no more matches.
 * @see #usearch_last
 * @see #usearch_getOffset
 * @see #USEARCH_DONE
 * @stable ICU 2.4
 */
 U_CAPI 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_CAPI void U_EXPORT2 usearch_reset(UStringSearch *strsrch);
 
 #ifndef U_HIDE_INTERNAL_API
 /**
   *  Simple forward search for the pattern, starting at a specified index,
   *     and using a default set search options.
   *
   *  This is an experimental function, and is not an official part of the
   *      ICU API.
   *
   *  The collator options, such as UCOL_STRENGTH and UCOL_NORMALIZTION, are honored.
   *
   *  The UStringSearch options USEARCH_CANONICAL_MATCH, USEARCH_OVERLAP and
   *  any Break Iterator are ignored.
   *
   *  Matches obey the following constraints:
   *
   *      Characters at the start or end positions of a match that are ignorable
   *      for collation are not included as part of the match, unless they
   *      are part of a combining sequence, as described below.
   *
   *      A match will not include a partial combining sequence.  Combining
   *      character sequences  are considered to be  inseparable units,
   *      and either match the pattern completely, or are considered to not match
   *      at all.  Thus, for example, an A followed a combining accent mark will 
   *      not be found when searching for a plain (unaccented) A.   (unless
   *      the collation strength has been set to ignore all accents).
   *
   *      When beginning a search, the initial starting position, startIdx,
   *      is assumed to be an acceptable match boundary with respect to
   *      combining characters.  A combining sequence that spans across the
   *      starting point will not suppress a match beginning at startIdx.
   *
   *      Characters that expand to multiple collation elements
   *      (German sharp-S becoming 'ss', or the composed forms of accented
   *      characters, for example) also must match completely.
   *      Searching for a single 's' in a string containing only a sharp-s will 
   *      find no match.
   *
   *
   *  @param strsrch    the UStringSearch struct, which references both
   *                    the text to be searched  and the pattern being sought.
   *  @param startIdx   The index into the text to begin the search.
   *  @param matchStart An out parameter, the starting index of the matched text.
   *                    This parameter may be NULL.
   *                    A value of -1 will be returned if no match was found.
   *  @param matchLimit Out parameter, the index of the first position following the matched text.
   *                    The matchLimit will be at a suitable position for beginning a subsequent search
   *                    in the input text.
   *                    This parameter may be NULL.
   *                    A value of -1 will be returned if no match was found.
   *          
   *  @param status     Report any errors.  Note that no match found is not an error.
   *  @return           true if a match was found, false otherwise.
   *
   *  @internal
   */
 U_CAPI UBool U_EXPORT2 usearch_search(UStringSearch *strsrch,
                                           int32_t        startIdx,
                                           int32_t        *matchStart,
                                           int32_t        *matchLimit,
                                           UErrorCode     *status);
 
 /**
   *  Simple backwards search for the pattern, starting at a specified index,
   *     and using using a default set search options.
   *
   *  This is an experimental function, and is not an official part of the
   *      ICU API.
   *
   *  The collator options, such as UCOL_STRENGTH and UCOL_NORMALIZTION, are honored.
   *
   *  The UStringSearch options USEARCH_CANONICAL_MATCH, USEARCH_OVERLAP and
   *  any Break Iterator are ignored.
   *
   *  Matches obey the following constraints:
   *
   *      Characters at the start or end positions of a match that are ignorable
   *      for collation are not included as part of the match, unless they
   *      are part of a combining sequence, as described below.
   *
   *      A match will not include a partial combining sequence.  Combining
   *      character sequences  are considered to be  inseparable units,
   *      and either match the pattern completely, or are considered to not match
   *      at all.  Thus, for example, an A followed a combining accent mark will 
   *      not be found when searching for a plain (unaccented) A.   (unless
   *      the collation strength has been set to ignore all accents).
   *
   *      When beginning a search, the initial starting position, startIdx,
   *      is assumed to be an acceptable match boundary with respect to
   *      combining characters.  A combining sequence that spans across the
   *      starting point will not suppress a match beginning at startIdx.
   *
   *      Characters that expand to multiple collation elements
   *      (German sharp-S becoming 'ss', or the composed forms of accented
   *      characters, for example) also must match completely.
   *      Searching for a single 's' in a string containing only a sharp-s will 
   *      find no match.
   *
   *
   *  @param strsrch    the UStringSearch struct, which references both
   *                    the text to be searched  and the pattern being sought.
   *  @param startIdx   The index into the text to begin the search.
   *  @param matchStart An out parameter, the starting index of the matched text.
   *                    This parameter may be NULL.
   *                    A value of -1 will be returned if no match was found.
   *  @param matchLimit Out parameter, the index of the first position following the matched text.
   *                    The matchLimit will be at a suitable position for beginning a subsequent search
   *                    in the input text.
   *                    This parameter may be NULL.
   *                    A value of -1 will be returned if no match was found.
   *          
   *  @param status     Report any errors.  Note that no match found is not an error.
   *  @return           true if a match was found, false otherwise.
   *
   *  @internal
   */
 U_CAPI UBool U_EXPORT2 usearch_searchBackwards(UStringSearch *strsrch,
                                                    int32_t        startIdx,
                                                    int32_t        *matchStart,
                                                    int32_t        *matchLimit,
                                                    UErrorCode     *status);
 #endif  /* U_HIDE_INTERNAL_API */
 
 #endif /* #if !UCONFIG_NO_COLLATION  && !UCONFIG_NO_BREAK_ITERATION */
 
 #endif

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