/* ****************************************************************************** * Copyright (C) 1996-2011, International Business Machines * * Corporation and others. All Rights Reserved. * ****************************************************************************** */ /** * \file * \brief C++ API: Boyer-Moore StringSearch technology preview * \internal ICU 4.0.1 technology preview */ #ifndef B_M_SEARCH_H #define B_M_SEARCH_H #include "unicode/utypes.h" #if !UCONFIG_NO_COLLATION && !UCONFIG_NO_BREAK_ITERATION #include "unicode/uobject.h" #include "unicode/ucol.h" #include "unicode/colldata.h" U_NAMESPACE_BEGIN class BadCharacterTable; class GoodSuffixTable; class Target; #ifndef U_HIDE_INTERNAL_API /** * BoyerMooreSearch * * This object holds the information needed to do a Collation sensitive Boyer-Moore search. It encapulates * the pattern, the "bad character" and "good suffix" tables, the Collator-based data needed to compute them, * and a reference to the text being searched. * * To do a search, you fist need to get a <code>CollData</code> object by calling <code>CollData::open</code>. * Then you construct a <code>BoyerMooreSearch</code> object from the <code>CollData</code> object, the pattern * string and the target string. Then you call the <code>search</code> method. Here's a code sample: * * <pre> * void boyerMooreExample(UCollator *collator, UnicodeString *pattern, UnicodeString *target) * { * UErrorCode status = U_ZERO_ERROR; * CollData *collData = CollData::open(collator, status); * * if (U_FAILURE(status)) { * // could not create a CollData object * return; * } * * BoyerMooreSearch *search = new BoyerMooreSearch(collData, *patternString, target, status); * * if (U_FAILURE(status)) { * // could not create a BoyerMooreSearch object * CollData::close(collData); * return; * } * * int32_t offset = 0, start = -1, end = -1; * * // Find all matches * while (search->search(offset, start, end)) { * // process the match between start and end * ... * // advance past the match * offset = end; * } * * // at this point, if offset == 0, there were no matches * if (offset == 0) { * // handle the case of no matches * } * * delete search; * CollData::close(collData); * * // CollData objects are cached, so the call to * // CollData::close doesn't delete the object. * // Call this if you don't need the object any more. * CollData::flushCollDataCache(); * } * </pre> * * NOTE: This is a technology preview. The final version of this API may not bear any resenblence to this API. * * Knows linitations: * 1) Backwards searching has not been implemented. * * 2) For Han and Hangul characters, this code ignores any Collation tailorings. In general, * this isn't a problem, but in Korean locals, at strength 1, Hangul characters are tailored * to be equal to Han characters with the same pronounciation. Because this code ignroes * tailorings, searching for a Hangul character will not find a Han character and visa-versa. * * 3) In some cases, searching for a pattern that needs to be normalized and ends * in a discontiguous contraction may fail. The only known cases of this are with * the Tibetan script. For example searching for the pattern * "\u0F7F\u0F80\u0F81\u0F82\u0F83\u0F84\u0F85" will fail. (This case is artificial. We've * been unable to find a pratical, real-world example of this failure.) * * @internal ICU 4.0.1 technology preview * * @see CollData */ class U_I18N_API BoyerMooreSearch : public UObject { public: /** * Construct a <code>BoyerMooreSearch</code> object. * * @param theData - A <code>CollData</code> object holding the Collator-sensitive data * @param patternString - the string for which to search * @param targetString - the string in which to search or <code>NULL</code> if youu will * set it later by calling <code>setTargetString</code>. * @param status - will be set if any errors occur. * * Note: if on return, status is set to an error code, * the only safe thing to do with this object is to call * the destructor. * * @internal ICU 4.0.1 technology preview */ BoyerMooreSearch(CollData *theData, const UnicodeString &patternString, const UnicodeString *targetString, UErrorCode &status); /** * The desstructor * * @internal ICU 4.0.1 technology preview */ ~BoyerMooreSearch(); /** * Test the pattern to see if it generates any CEs. * * @return <code>TRUE</code> if the pattern string did not generate any CEs * * @internal ICU 4.0.1 technology preview */ UBool empty(); /** * Search for the pattern string in the target string. * * @param offset - the offset in the target string at which to begin the search * @param start - will be set to the starting offset of the match, or -1 if there's no match * @param end - will be set to the ending offset of the match, or -1 if there's no match * * @return <code>TRUE</code> if the match succeeds, <code>FALSE</code> otherwise. * * @internal ICU 4.0.1 technology preview */ UBool search(int32_t offset, int32_t &start, int32_t &end); /** * Set the target string for the match. * * @param targetString - the new target string * @param status - will be set if any errors occur. * * @internal ICU 4.0.1 technology preview */ void setTargetString(const UnicodeString *targetString, UErrorCode &status); // **** no longer need these? **** /** * Return the <code>CollData</code> object used for searching * * @return the <code>CollData</code> object used for searching * * @internal ICU 4.0.1 technology preview */ CollData *getData(); /** * Return the CEs generated by the pattern string. * * @return a <code>CEList</code> object holding the CEs generated by the pattern string. * * @internal ICU 4.0.1 technology preview */ CEList *getPatternCEs(); /** * Return the <code>BadCharacterTable</code> object computed for the pattern string. * * @return the <code>BadCharacterTable</code> object. * * @internal ICU 4.0.1 technology preview */ BadCharacterTable *getBadCharacterTable(); /** * Return the <code>GoodSuffixTable</code> object computed for the pattern string. * * @return the <code>GoodSuffixTable</code> object computed for the pattern string. * * @internal ICU 4.0.1 technology preview */ GoodSuffixTable *getGoodSuffixTable(); /** * UObject glue... * @internal ICU 4.0.1 technology preview */ virtual UClassID getDynamicClassID() const; /** * UObject glue... * @internal ICU 4.0.1 technology preview */ static UClassID getStaticClassID(); private: CollData *data; CEList *patCEs; BadCharacterTable *badCharacterTable; GoodSuffixTable *goodSuffixTable; UnicodeString pattern; Target *target; }; #endif /* U_HIDE_INTERNAL_API */ U_NAMESPACE_END #endif // #if !UCONFIG_NO_COLLATION #endif // #ifndef B_M_SEARCH_H