Check in the pristine copy of ICU 4.6...

icu46/source/i18n/unicode/search.h

+/*
+**********************************************************************
+*   Copyright (C) 2001-2008 IBM and others. All rights reserved.
+**********************************************************************
+*   Date        Name        Description
+*  03/22/2000   helena      Creation.
+**********************************************************************
+*/
+
+#ifndef SEARCH_H
+#define SEARCH_H
+
+#include "unicode/utypes.h"
+
+/**
+ * \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 occurances 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.getMatchLength());
+ * }
+ * </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(void) 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(void) 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(void) 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>NULL</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>NULL</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(void) 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(void) 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 UBool 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
+     */
+    UBool 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(void) 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 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 USEARCH_DONE
+     * @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
+     * @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>NULL</tt>, no break detection is attempted.  
+     * @see #handleNext
+     * @see #handlePrev
+     * @stable ICU 2.0
+     */
+    SearchIterator(const UnicodeString &text, 
+                         BreakIterator *breakiter = NULL);
+
+    /**
+     * 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>NULL</tt>, no break detection is attempted.
+     * @see #handleNext
+     * @see #handlePrev
+     * @stable ICU 2.0
+     */
+    SearchIterator(CharacterIterator &text, BreakIterator *breakiter = NULL);
+
+    // 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 UBool SearchIterator::operator!=(const SearchIterator &that) const
+{
+   return !operator==(that); 
+}
+U_NAMESPACE_END
+
+#endif /* #if !UCONFIG_NO_COLLATION */
+
+#endif
+