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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 ß 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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