/*
******************************************************************************
* Copyright (C) 1996-2009, 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;
/**
* 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 CollData
object by calling CollData::open
.
* Then you construct a BoyerMooreSearch
object from the CollData
object, the pattern
* string and the target string. Then you call the search
method. Here's a code sample:
*
*
* 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(); * } ** * 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
BoyerMooreSearch
object.
*
* @param theData - A CollData
object holding the Collator-sensitive data
* @param patternString - the string for which to search
* @param targetString - the string in which to search or NULL
if youu will
* set it later by calling setTargetString
.
* @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 TRUE
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 TRUE
if the match succeeds, FALSE
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 CollData
object used for searching
*
* @return the CollData
object used for searching
*
* @internal ICU 4.0.1 technology preview
*/
CollData *getData();
/**
* Return the CEs generated by the pattern string.
*
* @return a CEList
object holding the CEs generated by the pattern string.
*
* @internal ICU 4.0.1 technology preview
*/
CEList *getPatternCEs();
/**
* Return the BadCharacterTable
object computed for the pattern string.
*
* @return the BadCharacterTable
object.
*
* @internal ICU 4.0.1 technology preview
*/
BadCharacterTable *getBadCharacterTable();
/**
* Return the GoodSuffixTable
object computed for the pattern string.
*
* @return the GoodSuffixTable
object computed for the pattern string.
*
* @internal ICU 4.0.1 technology preview
*/
GoodSuffixTable *getGoodSuffixTable();
/**
* UObject glue...
*/
virtual UClassID getDynamicClassID() const;
/**
* UObject glue...
*/
static UClassID getStaticClassID();
private:
CollData *data;
CEList *patCEs;
BadCharacterTable *badCharacterTable;
GoodSuffixTable *goodSuffixTable;
UnicodeString pattern;
Target *target;
};
U_NAMESPACE_END
#endif // #if !UCONFIG_NO_COLLATION
#endif // #ifndef B_M_SEARCH_H