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 /*

 **********************************************************************

 *   Copyright (C) 2001-2011 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/localpointer.h"

 #include "unicode/ucol.h"

 #include "unicode/ucoleitr.h"

 #include "unicode/ubrk.h"

 /**

  * \file

  * \brief C API: StringSearch

  *

  * C Apis for an engine that provides language-sensitive text searching based 

  * on the comparison rules defined in a <tt>UCollator</tt> data struct,

  * see <tt>ucol.h</tt>. This ensures that language eccentricity can be 

  * handled, e.g. for the German collator, characters ß and SS will be matched 

  * if case is chosen to be ignored. 

  * See the <a href="http://source.icu-project.org/repos/icu/icuhtml/trunk/design/collation/ICU_collation_design.htm">

  * "ICU Collation Design Document"</a> for more information.

  * <p> 

  * The algorithm implemented is a modified form of the Boyer Moore's search.

  * For more information  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, for further information on the algorithm.

  * <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 <tt>ubrk.h</tt>. 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 <tt>reset</tt> followed by a <tt>next</tt> or <tt>previous</tt>. 

  * Though a direction change can occur without calling <tt>reset</tt> 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>

  * <tt>usearch.h</tt> provides APIs to specify the starting position 

  * within the text string to be searched, e.g. <tt>usearch_setOffset</tt>,

  * <tt>usearch_preceding</tt> and <tt>usearch_following</tt>. 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>

  * 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 <tt>usearch_getCollator</tt> and using the APIs in <tt>ucol.h</tt>.

  * 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_getMatchLength(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 */

     USEARCH_OVERLAP,

     /** 

      * Option for canonical matches. option 1 in header documentation.

      * The default value will be USEARCH_OFF

      */

     USEARCH_CANONICAL_MATCH,

     /** 

      * Option to control how collation elements are compared.

      * The default value will be USEARCH_STANDARD_ELEMENT_COMPARISON.

      * @stable ICU 4.4

      */

     USEARCH_ELEMENT_COMPARISON,

     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,

     /** 

      * 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.

      * @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.

      * @stable ICU 4.4

      */

     USEARCH_ANY_BASE_WEIGHT_IS_WILDCARD,

     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 <tt>usearch_close</tt>.

 * @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 <tt>BreakIterator</tt>, the match will 

 *                  be rejected and another will be searched for. 

 *                  If this parameter is <tt>NULL</tt>, 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 <tt>BreakIterator</tt>, the match will 

 *                  be rejected and another will be searched for. 

 *                  If this parameter is <tt>NULL</tt>, 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 <tt>usearch_open</tt>, 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);

 #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_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), <tt>USEARCH_DONE</tt> 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.

 * <tt>USEARCH_DEFAULT</tt> 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 

 * <tt>usearch_first</tt>, <tt>usearch_next</tt>, <tt>usearch_previous</tt>, 

 * or <tt>usearch_last</tt>.

 * Just after construction, or after a searching method returns 

 * <tt>USEARCH_DONE</tt>, this method will return <tt>USEARCH_DONE</tt>.

 * <p>

 * Use <tt>usearch_getMatchedLength</tt> 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 

 * <tt>usearch_first</tt>, <tt>usearch_next</tt>, <tt>usearch_previous</tt>, 

 * or <tt>usearch_last</tt>.

 * Just after construction, or after a searching method returns 

 * <tt>USEARCH_DONE</tt>, 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 

 * <tt>usearch_first</tt>, <tt>usearch_next</tt>, <tt>usearch_previous</tt>, 

 * or <tt>usearch_last</tt>.

 * If the iterator is not pointing at a valid match (e.g. just after 

 * construction or after <tt>USEARCH_DONE</tt> 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 

 * <tt>usearch_getMatchLength</tt>.

 * @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 <tt>BreakIterator</tt>, the match will 

 *                  be rejected and another will be searched for. 

 *                  If this parameter is <tt>NULL</tt>, 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 <tt>usearch_setBreakIterator</tt>. Note that 

 * <tt>NULL</tt> 

 * 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. 

 * <p>

 * Deleting the returned <tt>UCollator</tt> before calling 

 * <tt>usearch_close</tt> would cause the string search to fail.

 * <tt>usearch_close</tt> 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 

 * <tt>usearch_getOffset</tt>) is the match position if one was found.

 * If a match is not found, <tt>USEARCH_DONE</tt> will be returned and

 * the iterator will be adjusted to the index <tt>USEARCH_DONE</tt>.

 * @param strsrch search iterator data struct

 * @param status for errors if it occurs

 * @return The character index of the first match, or 

 * <tt>USEARCH_DONE</tt> 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 equal or greater than <tt>position</tt> at which

 * the string text

 * matches the search pattern. The iterator is adjusted so that its current 

 * index (as returned by <tt>usearch_getOffset</tt>) is the match position if 

 * one was found.

 * If a match is not found, <tt>USEARCH_DONE</tt> will be returned and

 * the iterator will be adjusted to the index <tt>USEARCH_DONE</tt>

 * <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 <tt>pos</tt>,

 *         or <tt>USEARCH_DONE</tt> 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 <tt>usearch_getOffset</tt>) is the match position if 

 * one was found.

 * If a match is not found, <tt>USEARCH_DONE</tt> will be returned and

 * the iterator will be adjusted to the index <tt>USEARCH_DONE</tt>.

 * @param strsrch search iterator data struct

 * @param status for errors if it occurs

 * @return The index of the first match, or <tt>USEARCH_DONE</tt> 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 <tt>position</tt> at which the string text 

 * matches the search pattern. The iterator is adjusted so that its current 

 * index (as returned by <tt>usearch_getOffset</tt>) is the match position if 

 * one was found.

 * If a match is not found, <tt>USEARCH_DONE</tt> will be returned and

 * the iterator will be adjusted to the index <tt>USEARCH_DONE</tt>

 * <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 <tt>USEARCH_OVERLAP</tt> option is off, the last index of the

 * result match is always less than <tt>position</tt>.

 * When <tt>USERARCH_OVERLAP</tt> is on, the result match may span across

 * <tt>position</tt>.

 * @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 <tt>pos</tt>,

 *         or <tt>USEARCH_DONE</tt> 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 <tt>usearch_getOffset</tt>) is the match position if 

 * one was found.

 * If a match is not found, <tt>USEARCH_DONE</tt> will be returned and

 * the iterator will be adjusted to the index <tt>USEARCH_DONE</tt>

 * @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 

 *         <tt>USEARCH_DONE</tt> 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 <tt>usearch_getOffset</tt>) is the match position if 

 * one was found.

 * If a match is not found, <tt>USEARCH_DONE</tt> will be returned and

 * the iterator will be adjusted to the index <tt>USEARCH_DONE</tt>

 * @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 <tt>USEARCH_DONE</tt> 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);

 #ifndef U_HIDE_INTERNAL_API

 /**

   *  Simple forward 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  inseperable 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 supress 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_INTERNAL 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  inseperable 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 supress 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_INTERNAL 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