// © 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 ß and SS will be matched * if case is chosen to be ignored. * See the <a href="http://source.icu-project.org/repos/icu/icuhtml/trunk/design/collation/ICU_collation_design.htm"> * "ICU Collation Design Document"</a> for more information. * <p> * 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