Check in the pristine copy of ICU 4.6...

icu46/source/i18n/unicode/usearch.h

+/*
+**********************************************************************
+*   Copyright (C) 2001-2010 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 &szlig; 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 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
+* @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);
+
+/**
+  *  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 /* #if !UCONFIG_NO_COLLATION  && !UCONFIG_NO_BREAK_ITERATION */
+
+#endif