75f1522155
work to do, but it's about time to give this code more exposure. git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@33176 a95241bf-73f2-0310-859d-f6bbb57e9c96
225 lines
7.1 KiB
C++
225 lines
7.1 KiB
C++
/*
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******************************************************************************
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* Copyright (C) 1996-2009, International Business Machines *
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* Corporation and others. All Rights Reserved. *
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******************************************************************************
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*/
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/**
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* \file
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* \brief C++ API: Boyer-Moore StringSearch technology preview
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* \internal ICU 4.0.1 technology preview
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*/
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#ifndef B_M_SEARCH_H
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#define B_M_SEARCH_H
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#include "unicode/utypes.h"
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#if !UCONFIG_NO_COLLATION
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#include "unicode/uobject.h"
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#include "unicode/ucol.h"
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#include "unicode/colldata.h"
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U_NAMESPACE_BEGIN
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class BadCharacterTable;
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class GoodSuffixTable;
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class Target;
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/**
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* BoyerMooreSearch
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*
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* This object holds the information needed to do a Collation sensitive Boyer-Moore search. It encapulates
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* the pattern, the "bad character" and "good suffix" tables, the Collator-based data needed to compute them,
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* and a reference to the text being searched.
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*
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* To do a search, you fist need to get a <code>CollData</code> object by calling <code>CollData::open</code>.
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* Then you construct a <code>BoyerMooreSearch</code> object from the <code>CollData</code> object, the pattern
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* string and the target string. Then you call the <code>search</code> method. Here's a code sample:
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*
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* <pre>
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* void boyerMooreExample(UCollator *collator, UnicodeString *pattern, UnicodeString *target)
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* {
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* UErrorCode status = U_ZERO_ERROR;
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* CollData *collData = CollData::open(collator, status);
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*
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* if (U_FAILURE(status)) {
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* // could not create a CollData object
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* return;
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* }
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*
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* BoyerMooreSearch *search = new BoyerMooreSearch(collData, *patternString, target, status);
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*
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* if (U_FAILURE(status)) {
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* // could not create a BoyerMooreSearch object
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* CollData::close(collData);
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* return;
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* }
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*
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* int32_t offset = 0, start = -1, end = -1;
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*
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* // Find all matches
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* while (search->search(offset, start, end)) {
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* // process the match between start and end
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* ...
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* // advance past the match
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* offset = end;
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* }
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*
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* // at this point, if offset == 0, there were no matches
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* if (offset == 0) {
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* // handle the case of no matches
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* }
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*
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* delete search;
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* CollData::close(collData);
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*
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* // CollData objects are cached, so the call to
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* // CollData::close doesn't delete the object.
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* // Call this if you don't need the object any more.
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* CollData::flushCollDataCache();
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* }
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* </pre>
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*
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* NOTE: This is a technology preview. The final version of this API may not bear any resenblence to this API.
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*
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* Knows linitations:
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* 1) Backwards searching has not been implemented.
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*
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* 2) For Han and Hangul characters, this code ignores any Collation tailorings. In general,
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* this isn't a problem, but in Korean locals, at strength 1, Hangul characters are tailored
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* to be equal to Han characters with the same pronounciation. Because this code ignroes
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* tailorings, searching for a Hangul character will not find a Han character and visa-versa.
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*
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* 3) In some cases, searching for a pattern that needs to be normalized and ends
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* in a discontiguous contraction may fail. The only known cases of this are with
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* the Tibetan script. For example searching for the pattern
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* "\u0F7F\u0F80\u0F81\u0F82\u0F83\u0F84\u0F85" will fail. (This case is artificial. We've
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* been unable to find a pratical, real-world example of this failure.)
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*
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* @internal ICU 4.0.1 technology preview
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*
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* @see CollData
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*/
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class U_I18N_API BoyerMooreSearch : public UObject
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{
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public:
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/**
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* Construct a <code>BoyerMooreSearch</code> object.
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*
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* @param theData - A <code>CollData</code> object holding the Collator-sensitive data
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* @param patternString - the string for which to search
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* @param targetString - the string in which to search or <code>NULL</code> if youu will
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* set it later by calling <code>setTargetString</code>.
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* @param status - will be set if any errors occur.
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*
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* Note: if on return, status is set to an error code,
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* the only safe thing to do with this object is to call
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* the destructor.
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*
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* @internal ICU 4.0.1 technology preview
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*/
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BoyerMooreSearch(CollData *theData, const UnicodeString &patternString, const UnicodeString *targetString, UErrorCode &status);
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/**
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* The desstructor
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*
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* @internal ICU 4.0.1 technology preview
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*/
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~BoyerMooreSearch();
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/**
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* Test the pattern to see if it generates any CEs.
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*
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* @return <code>TRUE</code> if the pattern string did not generate any CEs
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*
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* @internal ICU 4.0.1 technology preview
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*/
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UBool empty();
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/**
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* Search for the pattern string in the target string.
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*
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* @param offset - the offset in the target string at which to begin the search
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* @param start - will be set to the starting offset of the match, or -1 if there's no match
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* @param end - will be set to the ending offset of the match, or -1 if there's no match
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*
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* @return <code>TRUE</code> if the match succeeds, <code>FALSE</code> otherwise.
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*
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* @internal ICU 4.0.1 technology preview
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*/
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UBool search(int32_t offset, int32_t &start, int32_t &end);
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/**
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* Set the target string for the match.
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*
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* @param targetString - the new target string
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* @param status - will be set if any errors occur.
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*
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* @internal ICU 4.0.1 technology preview
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*/
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void setTargetString(const UnicodeString *targetString, UErrorCode &status);
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// **** no longer need these? ****
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/**
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* Return the <code>CollData</code> object used for searching
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*
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* @return the <code>CollData</code> object used for searching
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*
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* @internal ICU 4.0.1 technology preview
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*/
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CollData *getData();
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/**
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* Return the CEs generated by the pattern string.
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*
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* @return a <code>CEList</code> object holding the CEs generated by the pattern string.
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*
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* @internal ICU 4.0.1 technology preview
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*/
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CEList *getPatternCEs();
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/**
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* Return the <code>BadCharacterTable</code> object computed for the pattern string.
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*
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* @return the <code>BadCharacterTable</code> object.
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*
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* @internal ICU 4.0.1 technology preview
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*/
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BadCharacterTable *getBadCharacterTable();
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/**
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* Return the <code>GoodSuffixTable</code> object computed for the pattern string.
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*
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* @return the <code>GoodSuffixTable</code> object computed for the pattern string.
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*
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* @internal ICU 4.0.1 technology preview
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*/
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GoodSuffixTable *getGoodSuffixTable();
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/**
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* UObject glue...
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*/
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virtual UClassID getDynamicClassID() const;
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/**
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* UObject glue...
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*/
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static UClassID getStaticClassID();
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private:
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CollData *data;
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CEList *patCEs;
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BadCharacterTable *badCharacterTable;
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GoodSuffixTable *goodSuffixTable;
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UnicodeString pattern;
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Target *target;
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};
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U_NAMESPACE_END
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#endif // #if !UCONFIG_NO_COLLATION
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#endif // #ifndef B_M_SEARCH_H
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