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// © 2016 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
/*
**********************************************************************
* Copyright (C) 2001-2011 IBM and others. All rights reserved.
**********************************************************************
* Date Name Description
* 03/22/2000 helena Creation.
**********************************************************************
*/
#ifndef SEARCH_H
#define SEARCH_H
#include "unicode/utypes.h"
#if U_SHOW_CPLUSPLUS_API
/**
* \file
* \brief C++ API: SearchIterator object.
*/
#if !UCONFIG_NO_COLLATION && !UCONFIG_NO_BREAK_ITERATION
#include "unicode/uobject.h"
#include "unicode/unistr.h"
#include "unicode/chariter.h"
#include "unicode/brkiter.h"
#include "unicode/usearch.h"
/**
* @stable ICU 2.0
*/
struct USearch;
/**
* @stable ICU 2.0
*/
typedef struct USearch USearch;
U_NAMESPACE_BEGIN
/**
*
* <tt>SearchIterator</tt> is an abstract base class that provides
* methods to search for a pattern within a text string. Instances of
* <tt>SearchIterator</tt> maintain a current position and scans over the
* target text, returning the indices the pattern is matched and the length
* of each match.
* <p>
* <tt>SearchIterator</tt> defines a protocol for text searching.
* Subclasses provide concrete implementations of various search algorithms.
* For example, <tt>StringSearch</tt> implements language-sensitive pattern
* matching based on the comparison rules defined in a
* <tt>RuleBasedCollator</tt> object.
* <p>
* Other options for searching includes using a BreakIterator to restrict
* the points at which matches are detected.
* <p>
* <tt>SearchIterator</tt> provides an API that is similar to that of
* other text iteration classes such as <tt>BreakIterator</tt>. Using
* this class, it is easy to scan through text looking for all occurrences of
* a given pattern. The following example uses a <tt>StringSearch</tt>
* object to find all instances of "fox" in the target string. Any other
* subclass of <tt>SearchIterator</tt> can be used in an identical
* manner.
* <pre><code>
* UnicodeString target("The quick brown fox jumped over the lazy fox");
* UnicodeString pattern("fox");
*
* SearchIterator *iter = new StringSearch(pattern, target);
* UErrorCode error = U_ZERO_ERROR;
* 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.getMatchedLength());
* }
* </code></pre>
*
* @see StringSearch
* @see RuleBasedCollator
*/
class U_I18N_API SearchIterator : public UObject {
public:
// public constructors and destructors -------------------------------
/**
* Copy constructor that creates a SearchIterator instance with the same
* behavior, and iterating over the same text.
* @param other the SearchIterator instance to be copied.
* @stable ICU 2.0
*/
SearchIterator(const SearchIterator &other);
/**
* Destructor. Cleans up the search iterator data struct.
* @stable ICU 2.0
*/
virtual ~SearchIterator();
// 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) = 0;
/**
* 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() const = 0;
/**
* Sets the text searching attributes located in the enum
* USearchAttribute with values from the enum USearchAttributeValue.
* USEARCH_DEFAULT can be used for all attributes for resetting.
* @param attribute text attribute (enum USearchAttribute) to be set
* @param value text attribute value
* @param status for errors if it occurs
* @stable ICU 2.0
*/
void setAttribute(USearchAttribute attribute,
USearchAttributeValue value,
UErrorCode &status);
/**
* Gets the text searching attributes
* @param attribute text attribute (enum USearchAttribute) to be retrieve
* @return text attribute value
* @stable ICU 2.0
*/
USearchAttributeValue getAttribute(USearchAttribute attribute) const;
/**
* Returns the index to the match in the text string that was searched.
* This call returns a valid result only after a successful call to
* <tt>first</tt>, <tt>next</tt>, <tt>previous</tt>, or <tt>last</tt>.
* Just after construction, or after a searching method returns
* <tt>USEARCH_DONE</tt>, this method will return <tt>USEARCH_DONE</tt>.
* <p>
* Use getMatchedLength to get the matched string length.
* @return index of a substring within the text string that is being
* searched.
* @see #first
* @see #next
* @see #previous
* @see #last
* @stable ICU 2.0
*/
int32_t getMatchedStart() const;
/**
* Returns the length of text in the string which matches the search
* pattern. This call returns a valid result only after a successful call
* to <tt>first</tt>, <tt>next</tt>, <tt>previous</tt>, or <tt>last</tt>.
* Just after construction, or after a searching method returns
* <tt>USEARCH_DONE</tt>, this method will return 0.
* @return The length of the match in the target text, or 0 if there
* is no match currently.
* @see #first
* @see #next
* @see #previous
* @see #last
* @stable ICU 2.0
*/
int32_t getMatchedLength() const;
/**
* Returns the text that was matched by the most recent call to
* <tt>first</tt>, <tt>next</tt>, <tt>previous</tt>, or <tt>last</tt>.
* If the iterator is not pointing at a valid match (e.g. just after
* construction or after <tt>USEARCH_DONE</tt> has been returned,
* returns an empty string.
* @param result stores the matched string or an empty string if a match
* is not found.
* @see #first
* @see #next
* @see #previous
* @see #last
* @stable ICU 2.0
*/
void getMatchedText(UnicodeString &result) const;
/**
* Set the BreakIterator that will be used to restrict the points
* at which matches are detected. The user is responsible for deleting
* the breakiterator.
* @param breakiter A BreakIterator that will be used to restrict the
* points at which matches are detected. If a match is
* found, but the match's start or end index is not a
* boundary as determined by the <tt>BreakIterator</tt>,
* the match will be rejected and another will be searched
* for. If this parameter is <tt>nullptr</tt>, no break
* detection is attempted.
* @param status for errors if it occurs
* @see BreakIterator
* @stable ICU 2.0
*/
void setBreakIterator(BreakIterator *breakiter, UErrorCode &status);
/**
* Returns the BreakIterator that is used to restrict the points at
* which matches are detected. This will be the same object that was
* passed to the constructor or to <tt>setBreakIterator</tt>.
* Note that <tt>nullptr</tt> is a legal value; it means that break
* detection should not be attempted.
* @return BreakIterator used to restrict matchings.
* @see #setBreakIterator
* @stable ICU 2.0
*/
const BreakIterator* getBreakIterator() const;
/**
* Set the string 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. The user is responsible for deleting the text.
* @param text string to be searched.
* @param status for errors. If the text length is 0,
* an U_ILLEGAL_ARGUMENT_ERROR is returned.
* @stable ICU 2.0
*/
virtual void setText(const UnicodeString &text, UErrorCode &status);
/**
* Set the string 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.
* <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.
* The user is responsible for deleting the text.
* @param text string iterator 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);
/**
* Return the string text to be searched.
* @return text string to be searched.
* @stable ICU 2.0
*/
const UnicodeString& getText() const;
// operator overloading ----------------------------------------------
/**
* Equality operator.
* @param that SearchIterator instance to be compared.
* @return true if both BreakIterators are of the same class, have the
* same behavior, terates over the same text and have the same
* attributes. false otherwise.
* @stable ICU 2.0
*/
virtual bool operator==(const SearchIterator &that) const;
/**
* Not-equal operator.
* @param that SearchIterator instance to be compared.
* @return false if operator== returns true, and vice versa.
* @stable ICU 2.0
*/
bool operator!=(const SearchIterator &that) const;
// public methods ----------------------------------------------------
/**
* Returns a copy of SearchIterator with the same behavior, and
* iterating over the same text, as this one. Note that all data will be
* replicated, except for the text string to be searched.
* @return cloned object
* @stable ICU 2.0
*/
virtual SearchIterator* safeClone() const = 0;
/**
* Returns the first index at which the string text matches the search
* pattern. The iterator is adjusted so that its current index (as
* returned by <tt>getOffset</tt>) is the match position if one
* was found.
* If a match is not found, <tt>USEARCH_DONE</tt> will be returned and
* the iterator will be adjusted to the index USEARCH_DONE
* @param status for errors if it occurs
* @return The character index of the first match, or
* <tt>USEARCH_DONE</tt> if there are no matches.
* @see #getOffset
* @stable ICU 2.0
*/
int32_t first(UErrorCode &status);
/**
* Returns the first index equal or greater than <tt>position</tt> at which the
* string text matches the search pattern. The iterator is adjusted so
* that its current index (as returned by <tt>getOffset</tt>) is the
* match position if one was found.
* If a match is not found, <tt>USEARCH_DONE</tt> will be returned and the
* iterator will be adjusted to the index <tt>USEARCH_DONE</tt>.
* @param position where search if to start from. 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
* @return The character index of the first match following
* <tt>position</tt>, or <tt>USEARCH_DONE</tt> if there are no
* matches.
* @see #getOffset
* @stable ICU 2.0
*/
int32_t following(int32_t position, UErrorCode &status);
/**
* Returns the last index in the target text at which it matches the
* search pattern. The iterator is adjusted so that its current index
* (as returned by <tt>getOffset</tt>) is the match position if one was
* found.
* If a match is not found, <tt>USEARCH_DONE</tt> will be returned and
* the iterator will be adjusted to the index USEARCH_DONE.
* @param status for errors if it occurs
* @return The index of the first match, or <tt>USEARCH_DONE</tt> if
* there are no matches.
* @see #getOffset
* @stable ICU 2.0
*/
int32_t last(UErrorCode &status);
/**
* Returns the first index less than <tt>position</tt> at which the string
* text matches the search pattern. The iterator is adjusted so that its
* current index (as returned by <tt>getOffset</tt>) is the match
* position if one was found. If a match is not found,
* <tt>USEARCH_DONE</tt> will be returned and the iterator will be
* adjusted to the index USEARCH_DONE
* <p>
* When <tt>USEARCH_OVERLAP</tt> option is off, the last index of the
* result match is always less than <tt>position</tt>.
* When <tt>USERARCH_OVERLAP</tt> is on, the result match may span across
* <tt>position</tt>.
*
* @param position where search is to start from. 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
* @return The character index of the first match preceding
* <tt>position</tt>, or <tt>USEARCH_DONE</tt> if there are
* no matches.
* @see #getOffset
* @stable ICU 2.0
*/
int32_t preceding(int32_t position, UErrorCode &status);
/**
* Returns the index of the next point at which the text matches the
* search pattern, starting from the current position
* The iterator is adjusted so that its current index (as returned by
* <tt>getOffset</tt>) is the match position if one was found.
* If a match is not found, <tt>USEARCH_DONE</tt> will be returned and
* the iterator will be adjusted to a position after the end of the text
* string.
* @param status for errors if it occurs
* @return The index of the next match after the current position,
* or <tt>USEARCH_DONE</tt> if there are no more matches.
* @see #getOffset
* @stable ICU 2.0
*/
int32_t next(UErrorCode &status);
/**
* Returns the index of the previous point at which the string text
* matches the search pattern, starting at the current position.
* The iterator is adjusted so that its current index (as returned by
* <tt>getOffset</tt>) is the match position if one was found.
* If a match is not found, <tt>USEARCH_DONE</tt> will be returned and
* the iterator will be adjusted to the index USEARCH_DONE
* @param status for errors if it occurs
* @return The index of the previous match before the current position,
* or <tt>USEARCH_DONE</tt> if there are no more matches.
* @see #getOffset
* @stable ICU 2.0
*/
int32_t previous(UErrorCode &status);
/**
* Resets 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();
protected:
// protected data members ---------------------------------------------
/**
* C search data struct
* @stable ICU 2.0
*/
USearch *m_search_;
/**
* Break iterator.
* Currently the C++ breakiterator does not have getRules etc to reproduce
* another in C. Hence we keep the original around and do the verification
* at the end of the match. The user is responsible for deleting this
* break iterator.
* @stable ICU 2.0
*/
BreakIterator *m_breakiterator_;
/**
* Unicode string version of the search text
* @stable ICU 2.0
*/
UnicodeString m_text_;
// protected constructors and destructors -----------------------------
/**
* Default constructor.
* Initializes data to the default values.
* @stable ICU 2.0
*/
SearchIterator();
/**
* Constructor for use by subclasses.
* @param text The target text to be searched.
* @param breakiter A {@link BreakIterator} that is used to restrict the
* points at which matches are detected. If
* <tt>handleNext</tt> or <tt>handlePrev</tt> finds a
* match, but the match's start or end index is not a
* boundary as determined by the <tt>BreakIterator</tt>,
* the match is rejected and <tt>handleNext</tt> or
* <tt>handlePrev</tt> is called again. If this parameter
* is <tt>nullptr</tt>, no break detection is attempted.
* @see #handleNext
* @see #handlePrev
* @stable ICU 2.0
*/
SearchIterator(const UnicodeString &text,
BreakIterator *breakiter = nullptr);
/**
* Constructor for use by subclasses.
* <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 text The target text to be searched.
* @param breakiter A {@link BreakIterator} that is used to restrict the
* points at which matches are detected. If
* <tt>handleNext</tt> or <tt>handlePrev</tt> finds a
* match, but the match's start or end index is not a
* boundary as determined by the <tt>BreakIterator</tt>,
* the match is rejected and <tt>handleNext</tt> or
* <tt>handlePrev</tt> is called again. If this parameter
* is <tt>nullptr</tt>, no break detection is attempted.
* @see #handleNext
* @see #handlePrev
* @stable ICU 2.0
*/
SearchIterator(CharacterIterator &text, BreakIterator *breakiter = nullptr);
// protected methods --------------------------------------------------
/**
* 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
*/
SearchIterator & operator=(const SearchIterator &that);
/**
* Abstract method which subclasses override to provide the mechanism
* for finding the next match in the target text. This allows different
* subclasses to provide different search algorithms.
* <p>
* If a match is found, the implementation should return the index at
* which the match starts and should call
* <tt>setMatchLength</tt> with the number of characters
* in the target text that make up the match. If no match is found, the
* method should return USEARCH_DONE.
* <p>
* @param position The index in the target text at which the search
* should start.
* @param status for error codes if it occurs.
* @return index at which the match starts, else if match is not found
* USEARCH_DONE is returned
* @see #setMatchLength
* @stable ICU 2.0
*/
virtual int32_t handleNext(int32_t position, UErrorCode &status)
= 0;
/**
* Abstract method which subclasses override to provide the mechanism for
* finding the previous match in the target text. This allows different
* subclasses to provide different search algorithms.
* <p>
* If a match is found, the implementation should return the index at
* which the match starts and should call
* <tt>setMatchLength</tt> with the number of characters
* in the target text that make up the match. If no match is found, the
* method should return USEARCH_DONE.
* <p>
* @param position The index in the target text at which the search
* should start.
* @param status for error codes if it occurs.
* @return index at which the match starts, else if match is not found
* USEARCH_DONE is returned
* @see #setMatchLength
* @stable ICU 2.0
*/
virtual int32_t handlePrev(int32_t position, UErrorCode &status)
= 0;
/**
* Sets the length of the currently matched string in the text string to
* be searched.
* Subclasses' <tt>handleNext</tt> and <tt>handlePrev</tt>
* methods should call this when they find a match in the target text.
* @param length length of the matched text.
* @see #handleNext
* @see #handlePrev
* @stable ICU 2.0
*/
virtual void setMatchLength(int32_t length);
/**
* Sets the offset of the currently matched string in the text string to
* be searched.
* Subclasses' <tt>handleNext</tt> and <tt>handlePrev</tt>
* methods should call this when they find a match in the target text.
* @param position start offset of the matched text.
* @see #handleNext
* @see #handlePrev
* @stable ICU 2.0
*/
virtual void setMatchStart(int32_t position);
/**
* sets match not found
* @stable ICU 2.0
*/
void setMatchNotFound();
};
inline bool SearchIterator::operator!=(const SearchIterator &that) const
{
return !operator==(that);
}
U_NAMESPACE_END
#endif /* #if !UCONFIG_NO_COLLATION */
#endif /* U_SHOW_CPLUSPLUS_API */
#endif
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