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