| /* |
| ********************************************************************** |
| * Copyright (C) 2001-2008 IBM and others. All rights reserved. |
| ********************************************************************** |
| * Date Name Description |
| * 03/22/2000 helena Creation. |
| ********************************************************************** |
| */ |
| |
| #ifndef STSEARCH_H |
| #define STSEARCH_H |
| |
| #include "unicode/utypes.h" |
| |
| /** |
| * \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> |
| * 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>BreakIterator</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. |
| * 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 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>getCollator</tt> and using the APIs in <tt>coll.h</tt>. |
| * Lastly to update StringSearch to the new collator attributes, |
| * 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, |
| * StringSearch 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.getMatchLength()); |
| * } |
| * </code></pre> |
| * <p> |
| * Note, StringSearch is not to be subclassed. |
| * </p> |
| * @see SearchIterator |
| * @see RuleBasedCollator |
| * @since ICU 2.0 |
| */ |
| |
| class U_I18N_API StringSearch : 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. This method causes internal data such as Boyer-Moore |
| * shift tables to be recalculated, but the iterator's position is |
| * unchanged. |
| * @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. |
| * Internal data like the Boyer Moore table will be recalculated, but |
| * the iterator's position is unchanged. |
| * @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 SearchIterator * safeClone(void) 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 ---------------------------------------------- |
| |
| /** |
| * RuleBasedCollator, contains exactly the same UCollator * in m_strsrch_ |
| * @stable ICU 2.0 |
| */ |
| RuleBasedCollator m_collator_; |
| /** |
| * 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 |
| |
