SearchIterator
is an abstract base class that provides methods to search for a pattern within a text string.
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#include <search.h>
Inheritance diagram for SearchIterator:
Public Member Functions | |
SearchIterator (const SearchIterator &other) | |
Copy constructor that creates a SearchIterator instance with the same behavior, and iterating over the same text. | |
virtual | ~SearchIterator () |
Destructor. | |
virtual void | setOffset (int32_t position, UErrorCode &status)=0 |
Sets the index to point to the given position, and clears any state that's affected. | |
virtual int32_t | getOffset (void) const =0 |
Return the current index in the text being searched. | |
void | setAttribute (USearchAttribute attribute, USearchAttributeValue value, UErrorCode &status) |
Sets the text searching attributes located in the enum USearchAttribute with values from the enum USearchAttributeValue. | |
USearchAttributeValue | getAttribute (USearchAttribute attribute) const |
Gets the text searching attributes. | |
int32_t | getMatchedStart (void) const |
Returns the index to the match in the text string that was searched. | |
int32_t | getMatchedLength (void) const |
Returns the length of text in the string which matches the search pattern. | |
void | getMatchedText (UnicodeString &result) const |
Returns the text that was matched by the most recent call to first , next , previous , or last . | |
void | setBreakIterator (BreakIterator *breakiter, UErrorCode &status) |
Set the BreakIterator that will be used to restrict the points at which matches are detected. | |
const BreakIterator * | getBreakIterator (void) const |
Returns the BreakIterator that is used to restrict the points at which matches are detected. | |
virtual void | setText (const UnicodeString &text, UErrorCode &status) |
Set the string text to be searched. | |
virtual void | setText (CharacterIterator &text, UErrorCode &status) |
Set the string text to be searched. | |
const UnicodeString & | getText (void) const |
Return the string text to be searched. | |
virtual UBool | operator== (const SearchIterator &that) const |
Equality operator. | |
UBool | operator!= (const SearchIterator &that) const |
Not-equal operator. | |
virtual SearchIterator * | safeClone (void) const =0 |
Returns a copy of SearchIterator with the same behavior, and iterating over the same text, as this one. | |
int32_t | first (UErrorCode &status) |
Returns the first index at which the string text matches the search pattern. | |
int32_t | following (int32_t position, UErrorCode &status) |
Returns the first index greater than position at which the string text matches the search pattern. | |
int32_t | last (UErrorCode &status) |
Returns the last index in the target text at which it matches the search pattern. | |
int32_t | preceding (int32_t position, UErrorCode &status) |
Returns the first index less than position at which the string text matches the search pattern. | |
int32_t | next (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 getOffset ) is the match position if one was found. | |
int32_t | previous (UErrorCode &status) |
Returns the index of the previous point at which the string text matches the search pattern, starting at the current position. | |
virtual void | reset () |
Resets the iteration. | |
Protected Member Functions | |
SearchIterator () | |
Default constructor. | |
SearchIterator (const UnicodeString &text, BreakIterator *breakiter=NULL) | |
Constructor for use by subclasses. | |
SearchIterator (CharacterIterator &text, BreakIterator *breakiter=NULL) | |
Constructor for use by subclasses. | |
SearchIterator & | operator= (const SearchIterator &that) |
Assignment operator. | |
virtual int32_t | handleNext (int32_t position, UErrorCode &status)=0 |
Abstract method which subclasses override to provide the mechanism for finding the next match in the target text. | |
virtual int32_t | handlePrev (int32_t position, UErrorCode &status)=0 |
Abstract method which subclasses override to provide the mechanism for finding the previous match in the target text. | |
virtual void | setMatchLength (int32_t length) |
Sets the length of the currently matched string in the text string to be searched. | |
virtual void | setMatchStart (int32_t position) |
Sets the offset of the currently matched string in the text string to be searched. | |
void | setMatchNotFound () |
sets match not found | |
Protected Attributes | |
USearch * | m_search_ |
C search data struct. | |
BreakIterator * | m_breakiterator_ |
Break iterator. | |
UnicodeString | m_text_ |
Unicode string version of the search text. |
SearchIterator
is an abstract base class that provides methods to search for a pattern within a text string.
Instances of SearchIterator
maintain a current position and scans over the target text, returning the indices the pattern is matched and the length of each match.
SearchIterator
defines a protocol for text searching. Subclasses provide concrete implementations of various search algorithms. For example, StringSearch
implements language-sensitive pattern matching based on the comparison rules defined in a RuleBasedCollator
object.
Other options for searching includes using a BreakIterator to restrict the points at which matches are detected.
SearchIterator
provides an API that is similar to that of other text iteration classes such as BreakIterator
. Using this class, it is easy to scan through text looking for all occurances of a given pattern. The following example uses a StringSearch
object to find all instances of "fox" in the target string. Any other subclass of SearchIterator
can be used in an identical manner.
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());
}
Definition at line 75 of file search.h.
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Copy constructor that creates a SearchIterator instance with the same behavior, and iterating over the same text.
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Destructor. Cleans up the search iterator data struct.
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Default constructor. Initializes data to the default values.
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Constructor for use by subclasses.
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Constructor for use by subclasses.
Note: No parsing of the text within the
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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
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Returns the first index greater than
The iterator is adjusted so that its current index (as returned by
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Gets the text searching attributes.
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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
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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
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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 Use getMatchedLength to get the matched string length.
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Returns the text that was matched by the most recent call to
If the iterator is not pointing at a valid match (e.g. just after construction or after
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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.
Implemented in StringSearch. |
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Return the string text to be searched.
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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.
If a match is found, the implementation should return the index at which the match starts and should call
Implemented in StringSearch. |
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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.
If a match is found, the implementation should return the index at which the match starts and should call
Implemented in StringSearch. |
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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
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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
If a match is not found,
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Not-equal operator.
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Assignment operator. Sets this iterator to have the same behavior, and iterate over the same text, as the one passed in.
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Equality operator.
Reimplemented in StringSearch. |
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Returns the first index less than
The iterator is adjusted so that its current index (as returned by
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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
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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.
Reimplemented in StringSearch. |
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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.
Implemented in StringSearch. |
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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.
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Set the BreakIterator that will be used to restrict the points at which matches are detected. The user is responsible for deleting the breakiterator.
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Sets the length of the currently matched string in the text string to be searched.
Subclasses'
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sets match not found
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Sets the offset of the currently matched string in the text string to be searched.
Subclasses'
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Sets the index to point to the given position, and clears any state that's affected. 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.
Implemented in StringSearch. |
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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.
Note: No parsing of the text within the
Reimplemented in StringSearch. |
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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.
Reimplemented in StringSearch. |
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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.
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C search data struct.
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Unicode string version of the search text.
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