scuffed-code/icu4c/source/samples/search/strsrch.h
Syn Wee Quek 2ba25d4bf8 ICU-1004
Added Makefile
Removed Linux compiler warnings.
Removed memory leak from line 637 from strsrch.cpp

X-SVN-Rev: 5043
2001-06-20 23:33:30 +00:00

394 lines
15 KiB
C++

/*
**********************************************************************
* Copyright (C) 1999-2000 IBM and others. All rights reserved.
**********************************************************************
* Date Name Description
* 03/22/2000 helena Creation.
**********************************************************************
*/
#ifndef STRSRCH_H
#define STRSRCH_H
#include "unicode/utypes.h"
#include "unicode/unistr.h"
#include "unicode/chariter.h"
#include "unicode/tblcoll.h"
#include "unicode/brkiter.h"
#include "srchiter.h"
class SearchIterator;
/**
* <code>StringSearch</code> is a <code>SearchIterator</code> that provides
* language-sensitive text searching based on the comparison rules defined
* in a {@link RuleBasedCollator} object.
* Instances of <code>StringSearch</code> function as iterators
* maintain a current position and scan over text returning the index of
* characters where the pattern occurs and the length of each match.
* <p>
* <code>StringSearch</code> uses a version of the fast Boyer-Moore search
* algorithm that has been adapted to work with the large character set of
* Unicode. See "Efficient Text Searching in Java", to be published in
* <i>Java Report</i> in February, 1999, for further information on the algorithm.
* <p>
* Consult the <code>SearchIterator</code> documentation for information on
* and examples of how to use instances of this class to implement text
* searching. <code>SearchIterator</code> provides all of the necessary
* API; this class only provides constructors and internal implementation
* methods.
*
* @see SearchIterator
* @see RuleBasedCollator
*
* @author Laura Werner
* @version 1.0
*/
class StringSearch : public SearchIterator
{
public:
/**
* Construct a <code>StringSearch</code> object using a specific collator and set
* of boundary-detection rules.
* <p>
* @param pat The text for which this object will search.
*
* @param target The text in which to search for the pattern.
*
* @param coll A <code>RuleBasedCollator</code> object which defines the
* language-sensitive comparison rules used to determine
* whether text in the pattern and target matches.
*
* @param breaker A <code>BreakIterator</code> 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 <code>BreakIterator</code> are ignored. If this behavior
* is not desired, <code>null</code> can be passed in instead.
*/
StringSearch(const UnicodeString& pat,
CharacterIterator* target,
RuleBasedCollator* coll,
BreakIterator* breaker,
UErrorCode& status);
/**
* Construct a <code>StringSearch</code> object using a specific collator.
* <p>
* @param pattern The text for which this object will search.
*
* @param target The text in which to search for the pattern.
*
* @param collator A <code>RuleBasedCollator</code> object which defines the
* language-sensitive comparison rules used to determine
* whether text in the pattern and target matches.
*/
StringSearch(const UnicodeString& pattern,
CharacterIterator* target,
RuleBasedCollator* collator,
UErrorCode& status);
/**
* copy constructor
*/
StringSearch(const StringSearch& that);
/**
* Construct a <code>StringSearch</code> object using the collator and
* character boundary detection rules for a given locale
* <p>
* @param pattern The text for which this object will search.
*
* @param target The text in which to search for the pattern.
*
* @param loc The locale whose collation and break-detection rules
* should be used.
*
* @exception ClassCastException thrown if the collator for the specified
* locale is not a RuleBasedCollator.
*/
StringSearch(const UnicodeString& pattern,
CharacterIterator* target,
const Locale& loc,
UErrorCode& status);
/**
* Construct a <code>StringSearch</code> object using the collator for the default
* locale
* <p>
* @param pattern The text for which this object will search.
*
* @param target The text in which to search for the pattern.
*
* @param collator A <code>RuleBasedCollator</code> object which defines the
* language-sensitive comparison rules used to determine
* whether text in the pattern and target matches.
*/
StringSearch(const UnicodeString& pattern,
const UnicodeString& target,
UErrorCode& status);
virtual ~StringSearch(void);
/**
* Assignment operator. Sets this iterator to have the same behavior,
* and iterate over the same text, as the one passed in.
*/
StringSearch& operator=(const StringSearch& that);
/**
* Equality operator. Returns TRUE if both BreakIterators are of the
* same class, have the same behavior, and iterate over the same text.
*/
virtual UBool operator==(const SearchIterator& that) const;
/**
* Not-equal operator. If operator== returns TRUE, this returns FALSE,
* and vice versa.
*/
UBool operator!=(const SearchIterator& that) const;
/**
* Returns a newly-constructed RuleBasedBreakIterator with the same
* behavior, and iterating over the same text, as this one.
*/
virtual SearchIterator* clone(void) const;
//-------------------------------------------------------------------
// Getters and Setters
//-------------------------------------------------------------------
/**
* Sets this object's strength property. The strength determines the
* minimum level of difference considered significant during a
* search. Generally, {@link Collator#TERTIARY} and
* {@link Collator#IDENTICAL} indicate that all differences are
* considered significant, {@link Collator#SECONDARY} indicates
* that upper/lower case distinctions should be ignored, and
* {@link Collator#PRIMARY} indicates that both case and accents
* should be ignored. However, the exact meanings of these constants
* are determined by individual Collator objects.
* <p>
* @see Collator#PRIMARY
* @see Collator#SECONDARY
* @see Collator#TERTIARY
* @see Collator#IDENTICAL
*/
void setStrength(Collator::ECollationStrength newStrength, UErrorCode& status);
/**
* Returns this object's strength property, which indicates what level
* of differences are considered significant during a search.
* <p>
* @see #setStrength
*/
Collator::ECollationStrength getStrength(void) const;
/**
* Set the collator to be used for this string search. Also changes
* the search strength to match that of the new collator.
* <p>
* This method causes internal data such as Boyer-Moore shift tables
* to be recalculated, but the iterator's position is unchanged.
* <p>
* @see #getCollator
*/
void setCollator(const RuleBasedCollator* coll, UErrorCode& status);
/**
* Return the RuleBasedCollator being used for this string search.
*/
const RuleBasedCollator& getCollator() const;
/**
* Set the pattern for which to search.
* This method causes internal data such as Boyer-Moore shift tables
* to be recalculated, but the iterator's position is unchanged.
*/
void setPattern(const UnicodeString& pat, UErrorCode& status);
/**
* Returns the pattern for which this object is searching.
*/
const UnicodeString& getPattern() const;
/**
* Set the target text which should be searched and resets the
* iterator's position to point before the start of the new text.
* This method is useful if you want to re-use an iterator to
* search for the same pattern within a different body of text.
*/
virtual void setTarget(const UnicodeString& newText);
/**
* Set the target text which should be searched and resets the
* iterator's position to point before the start of the target text.
* This method is useful if you want to re-use an iterator to
* search for the same pattern within a different body of text.
*
* @see #getTarget
*/
virtual void adoptTarget(CharacterIterator* iterator);
/** Reset iterator
*/
virtual void reset(void);
/**
* Returns a unique class ID POLYMORPHICALLY. Pure virtual override.
* This method is to implement a simple version of RTTI, since not all
* C++ compilers support genuine RTTI. Polymorphic operator==() and
* clone() methods call this method.
*
* @return The class ID for this object. All objects of a
* given class have the same class ID. Objects of
* other classes have different class IDs.
*/
inline virtual UClassID getDynamicClassID(void) const;
/**
* Returns the class ID for this class. This is useful only for
* comparing to a return value from getDynamicClassID(). For example:
*
* Base* polymorphic_pointer = createPolymorphicObject();
* if (polymorphic_pointer->getDynamicClassID() ==
* Derived::getStaticClassID()) ...
*
* @return The class ID for all objects of this class.
*/
inline static UClassID getStaticClassID(void);
protected:
//-------------------------------------------------------------------
// Privates
//-------------------------------------------------------------------
/**
* 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
* <code>DONE</code> and does not call <tt>setMatchLength</tt>.
* <p>
* @param start The index in the target text at which the search starts.
*
* @return The index at which the matched text in the target starts, or DONE
* if no match was found.
* <p>
* @see SearchIterator#next
* @see SearchIterator#DONE
*/
virtual int32_t handleNext(int32_t start, UErrorCode& status);
/**
* Search backward for matching text ,starting at a given location.
* Clients should not call this method directly; instead they should call
* <code>SearchIterator.previous()</code>, 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
* <code>DONE</code> and does not call <tt>setMatchLength</tt>.
* <p>
* @param start The index in the target text at which the search starts.
*
* @return The index at which the matched text in the target starts, or DONE
* if no match was found.
* <p>
* @see SearchIterator#previous
* @see SearchIterator#DONE
*/
virtual int32_t handlePrev(int32_t start, UErrorCode& status);
private:
/**
* Return a bitmask that will select only the portions of a collation
* element that are significant at the given strength level.
*/
static int32_t getMask(Collator::ECollationStrength strength);
void initialize(UErrorCode& status);
/**
* Method used by StringSearch to determine how far to the right to
* shift the pattern during a Boyer-Moore search.
*
* @param curValue The current value in the target text
* @param curIndex The index in the pattern at which we failed to match
* curValue in the target text.
*/
int32_t getShift( int32_t curValue, int32_t curIndex ) const;
/**
* Method used by StringSearch to determine how far to the left to
* shift the pattern during a reverse Boyer-Moore search.
*
* @param curValue The current value in the target text
* @param curIndex The index in the pattern at which we failed to match
* curValue in the target text.
*/
int32_t getBackShift( int32_t curValue, int32_t curIndex ) const;
/**
* Hash a collation element from its full size (32 bits) down into a
* value that can be used as an index into the shift tables. Right
* now we do a modulus by the size of the hash table.
*
* TODO: At some point I should experiment to see whether a slightly
* more complicated hash function gives us a better distribution
* on multilingual text. I doubt it will have much effect on
* performance, though.
*/
static int32_t hash(int32_t order);
//------------------------------------------------------------------------
// Private Data
//
CollationElementIterator *iter;
RuleBasedCollator *collator;
/* HSYS ? Why? Changes to this will not affect collator. no changes to the comparsion result */
Collator::ECollationStrength strength;
//------------------------------------------------------------------------
// Everything from here on down is the data used to represent the
// Boyer-Moore shift tables and the code that generates and manipulates
// them.
//
int32_t *valueList;
int32_t valueListLen;
int32_t shiftTable[256];
int32_t backShiftTable[256];
UnicodeString pattern; // The pattern string
int32_t normLen; // num. of collation elements in pattern.
int32_t minLen; // Min of composed, decomposed versions
int32_t maxLen; // Max
CollationElementIterator *it; // to be removed
private:
/* to be removed */
void dumpTables();
/**
* Class ID
*/
static char fgClassID;
};
inline UBool StringSearch::operator!=(const SearchIterator& that) const
{
return !operator==(that);
}
inline UClassID StringSearch::getDynamicClassID(void) const
{
return StringSearch::getStaticClassID();
}
inline UClassID StringSearch::getStaticClassID(void)
{
return (UClassID)(&fgClassID);
}
#endif