* Line boundary analysis determines where a text string can be broken * when line-wrapping. The mechanism correctly handles punctuation and * hyphenated words. *
* Sentence boundary analysis allows selection with correct * interpretation of periods within numbers and abbreviations, and * trailing punctuation marks such as quotation marks and parentheses. *
* Word boundary analysis is used by search and replace functions, as * well as within text editing applications that allow the user to * select words with a double click. Word selection provides correct * interpretation of punctuation marks within and following * words. Characters that are not part of a word, such as symbols or * punctuation marks, have word-breaks on both sides. *
* Character boundary analysis allows users to interact with * characters as they expect to, for example, when moving the cursor * through a text string. Character boundary analysis provides correct * navigation of through character strings, regardless of how the * character is stored. For example, an accented character might be * stored as a base character and a diacritical mark. What users * consider to be a character can differ between languages. *
* Title boundary analysis locates all positions, * typically starts of words, that should be set to Title Case * when title casing the text. *
* * This is the interface for all text boundaries. *
* Examples: *
* Helper function to output text *
* \code
* void printTextRange(UChar* str, int32_t start, int32_t end ) {
* UChar* result;
* UChar* temp;
* const char* res;
* temp=(UChar*)malloc(sizeof(UChar) * ((u_strlen(str)-start)+1));
* result=(UChar*)malloc(sizeof(UChar) * ((end-start)+1));
* u_strcpy(temp, &str[start]);
* u_strncpy(result, temp, end-start);
* res=(char*)malloc(sizeof(char) * (u_strlen(result)+1));
* u_austrcpy(res, result);
* printf("%s\n", res);
* }
* \endcode
*
* Print each element in order:
*
* \code
* void printEachForward( UBreakIterator* boundary, UChar* str) {
* int32_t end;
* int32_t start = ubrk_first(boundary);
* for (end = ubrk_next(boundary)); end != UBRK_DONE; start = end, end = ubrk_next(boundary)) {
* printTextRange(str, start, end );
* }
* }
* \endcode
*
* Print each element in reverse order:
*
* \code
* void printEachBackward( UBreakIterator* boundary, UChar* str) {
* int32_t start;
* int32_t end = ubrk_last(boundary);
* for (start = ubrk_previous(boundary); start != UBRK_DONE; end = start, start =ubrk_previous(boundary)) {
* printTextRange( str, start, end );
* }
* }
* \endcode
*
* Print first element
*
* \code
* void printFirst(UBreakIterator* boundary, UChar* str) {
* int32_t end;
* int32_t start = ubrk_first(boundary);
* end = ubrk_next(boundary);
* printTextRange( str, start, end );
* }
* \endcode
*
* Print last element
*
* \code
* void printLast(UBreakIterator* boundary, UChar* str) {
* int32_t start;
* int32_t end = ubrk_last(boundary);
* start = ubrk_previous(boundary);
* printTextRange(str, start, end );
* }
* \endcode
*
* Print the element at a specified position
*
* \code
* void printAt(UBreakIterator* boundary, int32_t pos , UChar* str) {
* int32_t start;
* int32_t end = ubrk_following(boundary, pos);
* start = ubrk_previous(boundary);
* printTextRange(str, start, end );
* }
* \endcode
*
* Creating and using text boundaries
*
* \code
* void BreakIterator_Example( void ) {
* UBreakIterator* boundary;
* UChar *stringToExamine;
* stringToExamine=(UChar*)malloc(sizeof(UChar) * (strlen("Aaa bbb ccc. Ddd eee fff.")+1) );
* u_uastrcpy(stringToExamine, "Aaa bbb ccc. Ddd eee fff.");
* printf("Examining: "Aaa bbb ccc. Ddd eee fff.");
*
* //print each sentence in forward and reverse order
* boundary = ubrk_open(UBRK_SENTENCE, "en_us", stringToExamine, u_strlen(stringToExamine), &status);
* printf("----- forward: -----------\n");
* printEachForward(boundary, stringToExamine);
* printf("----- backward: ----------\n");
* printEachBackward(boundary, stringToExamine);
* ubrk_close(boundary);
*
* //print each word in order
* boundary = ubrk_open(UBRK_WORD, "en_us", stringToExamine, u_strlen(stringToExamine), &status);
* printf("----- forward: -----------\n");
* printEachForward(boundary, stringToExamine);
* printf("----- backward: ----------\n");
* printEachBackward(boundary, stringToExamine);
* //print first element
* printf("----- first: -------------\n");
* printFirst(boundary, stringToExamine);
* //print last element
* printf("----- last: --------------\n");
* printLast(boundary, stringToExamine);
* //print word at charpos 10
* printf("----- at pos 10: ---------\n");
* printAt(boundary, 10 , stringToExamine);
*
* ubrk_close(boundary);
* }
* \endcode
*
*/
/** The possible types of text boundaries. */
typedef enum UBreakIteratorType {
/** Character breaks */
UBRK_CHARACTER,
/** Word breaks */
UBRK_WORD,
/** Line breaks */
UBRK_LINE,
/** Sentence breaks */
UBRK_SENTENCE,
/** Title Case breaks */
UBRK_TITLE
} UBreakIteratorType;
/** Value indicating all text boundaries have been returned.
*
*/
#define UBRK_DONE ((int32_t) -1)
/**
* Enum constants for the word break tags returned by
* getRuleStatus(). A range of values is defined for each category of
* word, to allow for further subdivisions of a category in future releases.
* Applications should check for tag values falling within the range, rather
* than for single individual values.
*/
typedef enum UWordBreak {
/** Tag value for "words" that do not fit into any of other categories.
* Includes spaces and most punctuation. */
UBRK_WORD_NONE = 0,
/** Upper bound for tags for uncategorized words. */
UBRK_WORD_NONE_LIMIT = 100,
/** Tag value for words that appear to be numbers, lower limit. */
UBRK_WORD_NUMBER = 100,
/** Tag value for words that appear to be numbers, upper limit. */
UBRK_WORD_NUMBER_LIMIT = 200,
/** Tag value for words that contain letters, excluding
* hiragana, katakana or ideographic characters, lower limit. */
UBRK_WORD_LETTER = 200,
/** Tag value for words containing letters, upper limit */
UBRK_WORD_LETTER_LIMIT = 300,
/** Tag value for words containing kana characters, lower limit */
UBRK_WORD_KANA = 300,
/** Tag value for words containing kana characters, upper limit */
UBRK_WORD_KANA_LIMIT = 400,
/** Tag value for words containing ideographic characters, lower limit */
UBRK_WORD_IDEO = 400,
/** Tag value for words containing ideographic characters, upper limit */
UBRK_WORD_IDEO_LIMIT = 500
} UWordBreak;
/**
* Open a new UBreakIterator for locating text boundaries for a specified locale.
* A UBreakIterator may be used for detecting character, line, word,
* and sentence breaks in text.
* @param type The type of UBreakIterator to open: one of UBRK_CHARACTER, UBRK_WORD,
* UBRK_LINE, UBRK_SENTENCE
* @param locale The locale specifying the text-breaking conventions.
* @param text The text to be iterated over.
* @param textLength The number of characters in text, or -1 if null-terminated.
* @param status A UErrorCode to receive any errors.
* @return A UBreakIterator for the specified locale.
* @see ubrk_openRules
* @stable ICU 2.0
*/
U_CAPI UBreakIterator* U_EXPORT2
ubrk_open(UBreakIteratorType type,
const char *locale,
const UChar *text,
int32_t textLength,
UErrorCode *status);
/**
* Open a new UBreakIterator for locating text boundaries using specified breaking rules.
* The rule syntax is ... (TBD)
* @param rules A set of rules specifying the text breaking conventions.
* @param rulesLength The number of characters in rules, or -1 if null-terminated.
* @param text The text to be iterated over. May be null, in which case ubrk_setText() is
* used to specify the text to be iterated.
* @param textLength The number of characters in text, or -1 if null-terminated.
* @param parseErr Receives position and context information for any syntax errors
* detected while parsing the rules.
* @param status A UErrorCode to receive any errors.
* @return A UBreakIterator for the specified rules.
* @see ubrk_open
* @draft ICU 2.2
*/
U_CAPI UBreakIterator* U_EXPORT2
ubrk_openRules(const UChar *rules,
int32_t rulesLength,
const UChar *text,
int32_t textLength,
UParseError *parseErr,
UErrorCode *status);
/**
* Thread safe cloning operation
* @param bi iterator to be cloned
* @param stackBuffer user allocated space for the new clone. If NULL new memory will be allocated.
* If buffer is not large enough, new memory will be allocated.
* Clients can use the U_BRK_SAFECLONE_BUFFERSIZE. This will probably be enough to avoid memory allocations.
* @param pBufferSize pointer to size of allocated space.
* If *pBufferSize == 0, a sufficient size for use in cloning will
* be returned ('pre-flighting')
* If *pBufferSize is not enough for a stack-based safe clone,
* new memory will be allocated.
* @param status to indicate whether the operation went on smoothly or there were errors
* An informational status value, U_SAFECLONE_ALLOCATED_ERROR, is used if any allocations were necessary.
* @return pointer to the new clone
* @stable ICU 2.0
*/
U_CAPI UBreakIterator * U_EXPORT2
ubrk_safeClone(
const UBreakIterator *bi,
void *stackBuffer,
int32_t *pBufferSize,
UErrorCode *status);
#define U_BRK_SAFECLONE_BUFFERSIZE 512
/**
* Close a UBreakIterator.
* Once closed, a UBreakIterator may no longer be used.
* @param bi The break iterator to close.
* @stable ICU 2.0
*/
U_CAPI void U_EXPORT2
ubrk_close(UBreakIterator *bi);
/**
* Sets an existing iterator to point to a new piece of text
* @param bi The iterator to use
* @param text The text to be set
* @param textLength The length of the text
* @param status The error code
* @stable ICU 2.0
*/
U_CAPI void U_EXPORT2
ubrk_setText(UBreakIterator* bi,
const UChar* text,
int32_t textLength,
UErrorCode* status);
/**
* Determine the most recently-returned text boundary.
*
* @param bi The break iterator to use.
* @return The character index most recently returned by \Ref{ubrk_next}, \Ref{ubrk_previous},
* \Ref{ubrk_first}, or \Ref{ubrk_last}.
* @stable ICU 2.0
*/
U_CAPI int32_t U_EXPORT2
ubrk_current(const UBreakIterator *bi);
/**
* Determine the text boundary following the current text boundary.
*
* @param bi The break iterator to use.
* @return The character index of the next text boundary, or UBRK_DONE
* if all text boundaries have been returned.
* @see ubrk_previous
* @stable ICU 2.0
*/
U_CAPI int32_t U_EXPORT2
ubrk_next(UBreakIterator *bi);
/**
* Determine the text boundary preceding the current text boundary.
*
* @param bi The break iterator to use.
* @return The character index of the preceding text boundary, or UBRK_DONE
* if all text boundaries have been returned.
* @see ubrk_next
* @stable ICU 2.0
*/
U_CAPI int32_t U_EXPORT2
ubrk_previous(UBreakIterator *bi);
/**
* Determine the index of the first character in the text being scanned.
* This is not always the same as index 0 of the text.
* @param bi The break iterator to use.
* @return The character index of the first character in the text being scanned.
* @see ubrk_last
* @stable ICU 2.0
*/
U_CAPI int32_t U_EXPORT2
ubrk_first(UBreakIterator *bi);
/**
* Determine the index immediately beyond the last character in the text being
* scanned.
* This is not the same as the last character.
* @param bi The break iterator to use.
* @return The character offset immediately beyond the last character in the
* text being scanned.
* @see ubrk_first
* @stable ICU 2.0
*/
U_CAPI int32_t U_EXPORT2
ubrk_last(UBreakIterator *bi);
/**
* Determine the text boundary preceding the specified offset.
* The value returned is always smaller than offset, or UBRK_DONE.
* @param bi The break iterator to use.
* @param offset The offset to begin scanning.
* @return The text boundary preceding offset, or UBRK_DONE.
* @see ubrk_following
* @stable ICU 2.0
*/
U_CAPI int32_t U_EXPORT2
ubrk_preceding(UBreakIterator *bi,
int32_t offset);
/**
* Determine the text boundary following the specified offset.
* The value returned is always greater than offset, or UBRK_DONE.
* @param bi The break iterator to use.
* @param offset The offset to begin scanning.
* @return The text boundary following offset, or UBRK_DONE.
* @see ubrk_preceding
* @stable ICU 2.0
*/
U_CAPI int32_t U_EXPORT2
ubrk_following(UBreakIterator *bi,
int32_t offset);
/**
* Get a locale for which text breaking information is available.
* A UBreakIterator in a locale returned by this function will perform the correct
* text breaking for the locale.
* @param index The index of the desired locale.
* @return A locale for which number text breaking information is available, or 0 if none.
* @see ubrk_countAvailable
* @stable ICU 2.0
*/
U_CAPI const char* U_EXPORT2
ubrk_getAvailable(int32_t index);
/**
* Determine how many locales have text breaking information available.
* This function is most useful as determining the loop ending condition for
* calls to \Ref{ubrk_getAvailable}.
* @return The number of locales for which text breaking information is available.
* @see ubrk_getAvailable
* @stable ICU 2.0
*/
U_CAPI int32_t U_EXPORT2
ubrk_countAvailable(void);
/**
* Returns true if the specfied position is a boundary position. As a side
* effect, leaves the iterator pointing to the first boundary position at
* or after "offset".
* @param bi The break iterator to use.
* @param offset the offset to check.
* @return True if "offset" is a boundary position.
* @stable ICU 2.0
*/
U_CAPI UBool U_EXPORT2
ubrk_isBoundary(UBreakIterator *bi, int32_t offset);
/**
* Return the status from the break rule that determined the most recently
* returned break position. The values appear in the rule source
* within brackets, {123}, for example. For rules that do not specify a
* status, a default value of 0 is returned.
* * For word break iterators, the possible values are defined in enum UWordBreak. * @draft ICU 2.2 */ U_CAPI int32_t U_EXPORT2 ubrk_getRuleStatus(UBreakIterator *bi); #endif /* #if !UCONFIG_NO_BREAK_ITERATION */ #endif