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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-28 14:29:10 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-28 14:29:10 +0000
commit2aa4a82499d4becd2284cdb482213d541b8804dd (patch)
treeb80bf8bf13c3766139fbacc530efd0dd9d54394c /intl/icu/source/i18n/unicode/stsearch.h
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Adding upstream version 86.0.1.upstream/86.0.1upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
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+// © 2016 and later: Unicode, Inc. and others.
+// License & terms of use: http://www.unicode.org/copyright.html
+/*
+**********************************************************************
+* Copyright (C) 2001-2014 IBM and others. All rights reserved.
+**********************************************************************
+* Date Name Description
+* 03/22/2000 helena Creation.
+**********************************************************************
+*/
+
+#ifndef STSEARCH_H
+#define STSEARCH_H
+
+#include "unicode/utypes.h"
+
+#if U_SHOW_CPLUSPLUS_API
+
+/**
+ * \file
+ * \brief C++ API: Service for searching text based on RuleBasedCollator.
+ */
+
+#if !UCONFIG_NO_COLLATION && !UCONFIG_NO_BREAK_ITERATION
+
+#include "unicode/tblcoll.h"
+#include "unicode/coleitr.h"
+#include "unicode/search.h"
+
+U_NAMESPACE_BEGIN
+
+/**
+ *
+ * <tt>StringSearch</tt> is a <tt>SearchIterator</tt> that provides
+ * language-sensitive text searching based on the comparison rules defined
+ * in a {@link RuleBasedCollator} object.
+ * StringSearch 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>
+ * 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>BreakIterator</tt>. 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 <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.
+ * Match results in the forward direction will match the result matches in
+ * the backwards direction in the reverse order
+ * <p>
+ * <tt>SearchIterator</tt> provides APIs to specify the starting position
+ * within the text string to be searched, e.g. <tt>setOffset</tt>,
+ * <tt>preceding</tt> and <tt>following</tt>. Since the
+ * starting position will be set as it is specified, please take note that
+ * there are some danger points 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 <tt>BreakIterator</tt> can be used if only matches at logical breaks are desired.
+ * Using a <tt>BreakIterator</tt> 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>getCollator</tt> and using the APIs in <tt>coll.h</tt>.
+ * Lastly to update <tt>StringSearch</tt> to the new collator attributes,
+ * <tt>reset</tt> 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,
+ * <tt>StringSearch</tt> does not guarantee the results for option 1.
+ * <p>
+ * Consult the <tt>SearchIterator</tt> documentation for information on
+ * and examples of how to use instances of this class to implement text
+ * searching.
+ * <pre><code>
+ * UnicodeString target("The quick brown fox jumps over the lazy dog.");
+ * UnicodeString pattern("fox");
+ *
+ * UErrorCode error = U_ZERO_ERROR;
+ * StringSearch iter(pattern, target, Locale::getUS(), NULL, status);
+ * for (int pos = iter.first(error);
+ * pos != USEARCH_DONE;
+ * pos = iter.next(error))
+ * {
+ * printf("Found match at %d pos, length is %d\n", pos, iter.getMatchedLength());
+ * }
+ * </code></pre>
+ * <p>
+ * Note, <tt>StringSearch</tt> is not to be subclassed.
+ * </p>
+ * @see SearchIterator
+ * @see RuleBasedCollator
+ * @since ICU 2.0
+ */
+
+class U_I18N_API StringSearch U_FINAL : public SearchIterator
+{
+public:
+
+ // public constructors and destructors --------------------------------
+
+ /**
+ * Creating a <tt>StringSearch</tt> instance using the argument locale
+ * language rule set. A collator will be created in the process, which
+ * will be owned by this instance and will be deleted during
+ * destruction
+ * @param pattern The text for which this object will search.
+ * @param text The text in which to search for the pattern.
+ * @param locale A locale which defines the language-sensitive
+ * comparison rules used to determine whether text in the
+ * pattern and target matches.
+ * @param breakiter A <tt>BreakIterator</tt> object used to constrain
+ * the matches that are found. Matches whose start and end
+ * indices in the target text are not boundaries as
+ * determined by the <tt>BreakIterator</tt> are
+ * ignored. If this behavior is not desired,
+ * <tt>NULL</tt> can be passed in instead.
+ * @param status for errors if any. If pattern or text is NULL, or if
+ * either the length of pattern or text is 0 then an
+ * U_ILLEGAL_ARGUMENT_ERROR is returned.
+ * @stable ICU 2.0
+ */
+ StringSearch(const UnicodeString &pattern, const UnicodeString &text,
+ const Locale &locale,
+ BreakIterator *breakiter,
+ UErrorCode &status);
+
+ /**
+ * Creating a <tt>StringSearch</tt> instance using the argument collator
+ * language rule set. Note, user retains the ownership of this collator,
+ * it does not get destroyed during this instance's destruction.
+ * @param pattern The text for which this object will search.
+ * @param text The text in which to search for the pattern.
+ * @param coll A <tt>RuleBasedCollator</tt> object which defines
+ * the language-sensitive comparison rules used to
+ * determine whether text in the pattern and target
+ * matches. User is responsible for the clearing of this
+ * object.
+ * @param breakiter A <tt>BreakIterator</tt> object used to constrain
+ * the matches that are found. Matches whose start and end
+ * indices in the target text are not boundaries as
+ * determined by the <tt>BreakIterator</tt> are
+ * ignored. If this behavior is not desired,
+ * <tt>NULL</tt> can be passed in instead.
+ * @param status for errors if any. If either the length of pattern or
+ * text is 0 then an U_ILLEGAL_ARGUMENT_ERROR is returned.
+ * @stable ICU 2.0
+ */
+ StringSearch(const UnicodeString &pattern,
+ const UnicodeString &text,
+ RuleBasedCollator *coll,
+ BreakIterator *breakiter,
+ UErrorCode &status);
+
+ /**
+ * Creating a <tt>StringSearch</tt> instance using the argument locale
+ * language rule set. A collator will be created in the process, which
+ * will be owned by this instance and will be deleted during
+ * destruction
+ * <p>
+ * Note: No parsing of the text within the <tt>CharacterIterator</tt>
+ * will be done during searching for this version. The block of text
+ * in <tt>CharacterIterator</tt> will be used as it is.
+ * @param pattern The text for which this object will search.
+ * @param text The text iterator in which to search for the pattern.
+ * @param locale A locale which defines the language-sensitive
+ * comparison rules used to determine whether text in the
+ * pattern and target matches. User is responsible for
+ * the clearing of this object.
+ * @param breakiter A <tt>BreakIterator</tt> object used to constrain
+ * the matches that are found. Matches whose start and end
+ * indices in the target text are not boundaries as
+ * determined by the <tt>BreakIterator</tt> are
+ * ignored. If this behavior is not desired,
+ * <tt>NULL</tt> can be passed in instead.
+ * @param status for errors if any. If either the length of pattern or
+ * text is 0 then an U_ILLEGAL_ARGUMENT_ERROR is returned.
+ * @stable ICU 2.0
+ */
+ StringSearch(const UnicodeString &pattern, CharacterIterator &text,
+ const Locale &locale,
+ BreakIterator *breakiter,
+ UErrorCode &status);
+
+ /**
+ * Creating a <tt>StringSearch</tt> instance using the argument collator
+ * language rule set. Note, user retains the ownership of this collator,
+ * it does not get destroyed during this instance's destruction.
+ * <p>
+ * Note: No parsing of the text within the <tt>CharacterIterator</tt>
+ * will be done during searching for this version. The block of text
+ * in <tt>CharacterIterator</tt> will be used as it is.
+ * @param pattern The text for which this object will search.
+ * @param text The text in which to search for the pattern.
+ * @param coll A <tt>RuleBasedCollator</tt> object which defines
+ * the language-sensitive comparison rules used to
+ * determine whether text in the pattern and target
+ * matches. User is responsible for the clearing of this
+ * object.
+ * @param breakiter A <tt>BreakIterator</tt> object used to constrain
+ * the matches that are found. Matches whose start and end
+ * indices in the target text are not boundaries as
+ * determined by the <tt>BreakIterator</tt> are
+ * ignored. If this behavior is not desired,
+ * <tt>NULL</tt> can be passed in instead.
+ * @param status for errors if any. If either the length of pattern or
+ * text is 0 then an U_ILLEGAL_ARGUMENT_ERROR is returned.
+ * @stable ICU 2.0
+ */
+ StringSearch(const UnicodeString &pattern, CharacterIterator &text,
+ RuleBasedCollator *coll,
+ BreakIterator *breakiter,
+ UErrorCode &status);
+
+ /**
+ * Copy constructor that creates a StringSearch instance with the same
+ * behavior, and iterating over the same text.
+ * @param that StringSearch instance to be copied.
+ * @stable ICU 2.0
+ */
+ StringSearch(const StringSearch &that);
+
+ /**
+ * Destructor. Cleans up the search iterator data struct.
+ * If a collator is created in the constructor, it will be destroyed here.
+ * @stable ICU 2.0
+ */
+ virtual ~StringSearch(void);
+
+ /**
+ * Clone this object.
+ * Clones can be used concurrently in multiple threads.
+ * If an error occurs, then NULL is returned.
+ * The caller must delete the clone.
+ *
+ * @return a clone of this object
+ *
+ * @see getDynamicClassID
+ * @stable ICU 2.8
+ */
+ StringSearch *clone() const;
+
+ // operator overloading ---------------------------------------------
+
+ /**
+ * Assignment operator. Sets this iterator to have the same behavior,
+ * and iterate over the same text, as the one passed in.
+ * @param that instance to be copied.
+ * @stable ICU 2.0
+ */
+ StringSearch & operator=(const StringSearch &that);
+
+ /**
+ * Equality operator.
+ * @param that instance to be compared.
+ * @return TRUE if both instances have the same attributes,
+ * breakiterators, collators and iterate over the same text
+ * while looking for the same pattern.
+ * @stable ICU 2.0
+ */
+ virtual UBool operator==(const SearchIterator &that) const;
+
+ // public get and set methods ----------------------------------------
+
+ /**
+ * Sets the index to point to the given position, and clears any state
+ * that's affected.
+ * <p>
+ * 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.
+ * @param position within the text to be set. If position is less
+ * than or greater than the text range for searching,
+ * an U_INDEX_OUTOFBOUNDS_ERROR will be returned
+ * @param status for errors if it occurs
+ * @stable ICU 2.0
+ */
+ virtual void setOffset(int32_t position, UErrorCode &status);
+
+ /**
+ * Return the current index in the text being searched.
+ * If the iteration has gone past the end of the text
+ * (or past the beginning for a backwards search), USEARCH_DONE
+ * is returned.
+ * @return current index in the text being searched.
+ * @stable ICU 2.0
+ */
+ virtual int32_t getOffset(void) const;
+
+ /**
+ * Set the target 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 text text string to be searched
+ * @param status for errors if any. If the text length is 0 then an
+ * U_ILLEGAL_ARGUMENT_ERROR is returned.
+ * @stable ICU 2.0
+ */
+ virtual void setText(const UnicodeString &text, UErrorCode &status);
+
+ /**
+ * Set the target 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.
+ * Note: No parsing of the text within the <tt>CharacterIterator</tt>
+ * will be done during searching for this version. The block of text
+ * in <tt>CharacterIterator</tt> will be used as it is.
+ * @param text text string to be searched
+ * @param status for errors if any. If the text length is 0 then an
+ * U_ILLEGAL_ARGUMENT_ERROR is returned.
+ * @stable ICU 2.0
+ */
+ virtual void setText(CharacterIterator &text, UErrorCode &status);
+
+ /**
+ * Gets the collator used for the language rules.
+ * <p>
+ * Caller may modify but <b>must not</b> delete the <tt>RuleBasedCollator</tt>!
+ * Modifications to this collator will affect the original collator passed in to
+ * the <tt>StringSearch></tt> constructor or to setCollator, if any.
+ * @return collator used for string search
+ * @stable ICU 2.0
+ */
+ RuleBasedCollator * getCollator() const;
+
+ /**
+ * Sets the collator used for the language rules. User retains the
+ * ownership of this collator, thus the responsibility of deletion lies
+ * with the user. The iterator's position will not be changed by this method.
+ * @param coll collator
+ * @param status for errors if any
+ * @stable ICU 2.0
+ */
+ void setCollator(RuleBasedCollator *coll, UErrorCode &status);
+
+ /**
+ * Sets the pattern used for matching.
+ * The iterator's position will not be changed by this method.
+ * @param pattern search pattern to be found
+ * @param status for errors if any. If the pattern length is 0 then an
+ * U_ILLEGAL_ARGUMENT_ERROR is returned.
+ * @stable ICU 2.0
+ */
+ void setPattern(const UnicodeString &pattern, UErrorCode &status);
+
+ /**
+ * Gets the search pattern.
+ * @return pattern used for matching
+ * @stable ICU 2.0
+ */
+ const UnicodeString & getPattern() const;
+
+ // public methods ----------------------------------------------------
+
+ /**
+ * 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.
+ * @stable ICU 2.0
+ */
+ virtual void reset();
+
+ /**
+ * Returns a copy of StringSearch with the same behavior, and
+ * iterating over the same text, as this one. Note that all data will be
+ * replicated, except for the user-specified collator and the
+ * breakiterator.
+ * @return cloned object
+ * @stable ICU 2.0
+ */
+ virtual StringSearch * safeClone() const;
+
+ /**
+ * ICU "poor man's RTTI", returns a UClassID for the actual class.
+ *
+ * @stable ICU 2.2
+ */
+ virtual UClassID getDynamicClassID() const;
+
+ /**
+ * ICU "poor man's RTTI", returns a UClassID for this class.
+ *
+ * @stable ICU 2.2
+ */
+ static UClassID U_EXPORT2 getStaticClassID();
+
+protected:
+
+ // protected method -------------------------------------------------
+
+ /**
+ * Search forward for matching text, starting at a given location.
+ * Clients should not call this method directly; instead they should
+ * call {@link SearchIterator#next }.
+ * <p>
+ * If a match is found, this method returns the index at which the match
+ * starts and calls {@link SearchIterator#setMatchLength } with the number
+ * of characters in the target text that make up the match. If no match
+ * is found, the method returns <tt>USEARCH_DONE</tt>.
+ * <p>
+ * The <tt>StringSearch</tt> is adjusted so that its current index
+ * (as returned by {@link #getOffset }) is the match position if one was
+ * found.
+ * If a match is not found, <tt>USEARCH_DONE</tt> will be returned and
+ * the <tt>StringSearch</tt> will be adjusted to the index USEARCH_DONE.
+ * @param position The index in the target text at which the search
+ * starts
+ * @param status for errors if any occurs
+ * @return The index at which the matched text in the target starts, or
+ * USEARCH_DONE if no match was found.
+ * @stable ICU 2.0
+ */
+ virtual int32_t handleNext(int32_t position, UErrorCode &status);
+
+ /**
+ * Search backward for matching text, starting at a given location.
+ * Clients should not call this method directly; instead they should call
+ * <tt>SearchIterator.previous()</tt>, which this method overrides.
+ * <p>
+ * If a match is found, this method returns the index at which the match
+ * starts and calls {@link SearchIterator#setMatchLength } with the number
+ * of characters in the target text that make up the match. If no match
+ * is found, the method returns <tt>USEARCH_DONE</tt>.
+ * <p>
+ * The <tt>StringSearch</tt> is adjusted so that its current index
+ * (as returned by {@link #getOffset }) is the match position if one was
+ * found.
+ * If a match is not found, <tt>USEARCH_DONE</tt> will be returned and
+ * the <tt>StringSearch</tt> will be adjusted to the index USEARCH_DONE.
+ * @param position The index in the target text at which the search
+ * starts.
+ * @param status for errors if any occurs
+ * @return The index at which the matched text in the target starts, or
+ * USEARCH_DONE if no match was found.
+ * @stable ICU 2.0
+ */
+ virtual int32_t handlePrev(int32_t position, UErrorCode &status);
+
+private :
+ StringSearch(); // default constructor not implemented
+
+ // private data members ----------------------------------------------
+
+ /**
+ * Pattern text
+ * @stable ICU 2.0
+ */
+ UnicodeString m_pattern_;
+ /**
+ * String search struct data
+ * @stable ICU 2.0
+ */
+ UStringSearch *m_strsrch_;
+
+};
+
+U_NAMESPACE_END
+
+#endif /* #if !UCONFIG_NO_COLLATION */
+
+#endif /* U_SHOW_CPLUSPLUS_API */
+
+#endif
+