* 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 identifies the boundaries of * "Extended Grapheme Clusters", which are groupings of codepoints * that should be treated as character-like units for many text operations. * Please see Unicode Standard Annex #29, Unicode Text Segmentation, * http://www.unicode.org/reports/tr29/ for additional information * on grapheme clusters and guidelines on their use. *
* Title boundary analysis locates all positions, * typically starts of words, that should be set to Title Case * when title casing the text. *
* The text boundary positions are found according to the rules * described in Unicode Standard Annex #29, Text Boundaries, and * Unicode Standard Annex #14, Line Breaking Properties. These * are available at http://www.unicode.org/reports/tr14/ and * http://www.unicode.org/reports/tr29/. *
* In addition to the plain C API defined in this header file, an * object oriented C++ API with equivalent functionality is defined in the * file brkiter.h. *
* Code snippets illustrating the use of the Break Iterator APIs
* are available in the ICU User Guide,
* http://icu-project.org/userguide/boundaryAnalysis.html
* and in the sample program icu/source/samples/break/break.cpp
*/
/** The possible types of text boundaries. @stable ICU 2.0 */
typedef enum UBreakIteratorType {
/** Character breaks @stable ICU 2.0 */
UBRK_CHARACTER = 0,
/** Word breaks @stable ICU 2.0 */
UBRK_WORD = 1,
/** Line breaks @stable ICU 2.0 */
UBRK_LINE = 2,
/** Sentence breaks @stable ICU 2.0 */
UBRK_SENTENCE = 3,
#ifndef U_HIDE_DEPRECATED_API
/**
* Title Case breaks
* The iterator created using this type locates title boundaries as described for
* Unicode 3.2 only. For Unicode 4.0 and above title boundary iteration,
* please use Word Boundary iterator.
*
* @deprecated ICU 2.8 Use the word break iterator for titlecasing for Unicode 4 and later.
*/
UBRK_TITLE = 4,
#endif /* U_HIDE_DEPRECATED_API */
UBRK_COUNT = 5
} UBreakIteratorType;
/** Value indicating all text boundaries have been returned.
* @stable ICU 2.0
*/
#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.
* @stable ICU 2.2
*/
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;
/**
* Enum constants for the line 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.
* @stable ICU 2.8
*/
typedef enum ULineBreakTag {
/** Tag value for soft line breaks, positions at which a line break
* is acceptable but not required */
UBRK_LINE_SOFT = 0,
/** Upper bound for soft line breaks. */
UBRK_LINE_SOFT_LIMIT = 100,
/** Tag value for a hard, or mandatory line break */
UBRK_LINE_HARD = 100,
/** Upper bound for hard line breaks. */
UBRK_LINE_HARD_LIMIT = 200
} ULineBreakTag;
/**
* Enum constants for the sentence break tags returned by getRuleStatus().
* A range of values is defined for each category of
* sentence, 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.
* @stable ICU 2.8
*/
typedef enum USentenceBreakTag {
/** Tag value for for sentences ending with a sentence terminator
* ('.', '?', '!', etc.) character, possibly followed by a
* hard separator (CR, LF, PS, etc.)
*/
UBRK_SENTENCE_TERM = 0,
/** Upper bound for tags for sentences ended by sentence terminators. */
UBRK_SENTENCE_TERM_LIMIT = 100,
/** Tag value for for sentences that do not contain an ending
* sentence terminator ('.', '?', '!', etc.) character, but
* are ended only by a hard separator (CR, LF, PS, etc.) or end of input.
*/
UBRK_SENTENCE_SEP = 100,
/** Upper bound for tags for sentences ended by a separator. */
UBRK_SENTENCE_SEP_LIMIT = 200
/** Tag value for a hard, or mandatory line break */
} USentenceBreakTag;
/**
* 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_STABLE 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
* @stable ICU 2.2
*/
U_STABLE 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 Deprecated functionality as of ICU 52, use NULL.
* 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.
* @param pBufferSize Deprecated functionality as of ICU 52, use NULL or 1.
* 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_STABLE UBreakIterator * U_EXPORT2
ubrk_safeClone(
const UBreakIterator *bi,
void *stackBuffer,
int32_t *pBufferSize,
UErrorCode *status);
#ifndef U_HIDE_DEPRECATED_API
/**
* A recommended size (in bytes) for the memory buffer to be passed to ubrk_saveClone().
* @deprecated ICU 52. Do not rely on ubrk_safeClone() cloning into any provided buffer.
*/
#define U_BRK_SAFECLONE_BUFFERSIZE 1
#endif /* U_HIDE_DEPRECATED_API */
/**
* Close a UBreakIterator.
* Once closed, a UBreakIterator may no longer be used.
* @param bi The break iterator to close.
* @stable ICU 2.0
*/
U_STABLE void U_EXPORT2
ubrk_close(UBreakIterator *bi);
#if U_SHOW_CPLUSPLUS_API
U_NAMESPACE_BEGIN
/**
* \class LocalUBreakIteratorPointer
* "Smart pointer" class, closes a UBreakIterator via ubrk_close().
* For most methods see the LocalPointerBase base class.
*
* @see LocalPointerBase
* @see LocalPointer
* @stable ICU 4.4
*/
U_DEFINE_LOCAL_OPEN_POINTER(LocalUBreakIteratorPointer, UBreakIterator, ubrk_close);
U_NAMESPACE_END
#endif
/**
* 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_STABLE void U_EXPORT2
ubrk_setText(UBreakIterator* bi,
const UChar* text,
int32_t textLength,
UErrorCode* status);
/**
* Sets an existing iterator to point to a new piece of text.
*
* All index positions returned by break iterator functions are
* native indices from the UText. For example, when breaking UTF-8
* encoded text, the break positions returned by \ref ubrk_next, \ref ubrk_previous, etc.
* will be UTF-8 string indices, not UTF-16 positions.
*
* @param bi The iterator to use
* @param text The text to be set.
* This function makes a shallow clone of the supplied UText. This means
* that the caller is free to immediately close or otherwise reuse the
* UText that was passed as a parameter, but that the underlying text itself
* must not be altered while being referenced by the break iterator.
* @param status The error code
* @stable ICU 3.4
*/
U_STABLE void U_EXPORT2
ubrk_setUText(UBreakIterator* bi,
UText* text,
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_STABLE int32_t U_EXPORT2
ubrk_current(const UBreakIterator *bi);
/**
* Advance the iterator to the boundary following the current 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_STABLE int32_t U_EXPORT2
ubrk_next(UBreakIterator *bi);
/**
* Set the iterator position to the boundary preceding the current 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_STABLE int32_t U_EXPORT2
ubrk_previous(UBreakIterator *bi);
/**
* Set the iterator position to zero, the start of the text being scanned.
* @param bi The break iterator to use.
* @return The new iterator position (zero).
* @see ubrk_last
* @stable ICU 2.0
*/
U_STABLE int32_t U_EXPORT2
ubrk_first(UBreakIterator *bi);
/**
* Set the iterator position to 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_STABLE int32_t U_EXPORT2
ubrk_last(UBreakIterator *bi);
/**
* Set the iterator position to the first boundary preceding the specified offset.
* The new position 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_STABLE int32_t U_EXPORT2
ubrk_preceding(UBreakIterator *bi,
int32_t offset);
/**
* Advance the iterator to the first 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_STABLE 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_STABLE 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_STABLE 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_STABLE 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. * @stable ICU 2.2 */ U_STABLE int32_t U_EXPORT2 ubrk_getRuleStatus(UBreakIterator *bi); /** * Get the statuses from the break rules that determined the most recently * returned break position. The values appear in the rule source * within brackets, {123}, for example. The default status value for rules * that do not explicitly provide one is zero. *
* For word break iterators, the possible values are defined in enum UWordBreak. * @param bi The break iterator to use * @param fillInVec an array to be filled in with the status values. * @param capacity the length of the supplied vector. A length of zero causes * the function to return the number of status values, in the * normal way, without attemtping to store any values. * @param status receives error codes. * @return The number of rule status values from rules that determined * the most recent boundary returned by the break iterator. * @stable ICU 3.0 */ U_STABLE int32_t U_EXPORT2 ubrk_getRuleStatusVec(UBreakIterator *bi, int32_t *fillInVec, int32_t capacity, UErrorCode *status); /** * Return the locale of the break iterator. You can choose between the valid and * the actual locale. * @param bi break iterator * @param type locale type (valid or actual) * @param status error code * @return locale string * @stable ICU 2.8 */ U_STABLE const char* U_EXPORT2 ubrk_getLocaleByType(const UBreakIterator *bi, ULocDataLocaleType type, UErrorCode* status); /** * Set the subject text string upon which the break iterator is operating * without changing any other aspect of the state. * The new and previous text strings must have the same content. * * This function is intended for use in environments where ICU is operating on * strings that may move around in memory. It provides a mechanism for notifying * ICU that the string has been relocated, and providing a new UText to access the * string in its new position. * * Note that the break iterator never copies the underlying text * of a string being processed, but always operates directly on the original text * provided by the user. Refreshing simply drops the references to the old text * and replaces them with references to the new. * * Caution: this function is normally used only by very specialized * system-level code. One example use case is with garbage collection * that moves the text in memory. * * @param bi The break iterator. * @param text The new (moved) text string. * @param status Receives errors detected by this function. * * @stable ICU 49 */ U_STABLE void U_EXPORT2 ubrk_refreshUText(UBreakIterator *bi, UText *text, UErrorCode *status); #endif /* #if !UCONFIG_NO_BREAK_ITERATION */ #endif