* Line boundary analysis determines where a text string can be broken * when line-wrapping. The mechanism correctly handles punctuation and * hyphenated words. *
* Note: The locale keyword "lb" can be used to modify line break
* behavior according to the CSS level 3 line-break options, see
*
* Sentence boundary analysis allows selection with correct
* interpretation of periods within numbers and abbreviations, and
* trailing punctuation marks such as quotation marks and parentheses.
*
* Note: The locale keyword "ss" can be used to enable use of
* segmentation suppression data (preventing breaks in English after
* abbreviations such as "Mr." or "Est.", for example), as follows:
* "en@ss=standard".
*
* 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,
* https://unicode-org.github.io/icu/userguide/boundaryanalysis/
* 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,
/**
* One more than the highest normal UBreakIteratorType value.
* @deprecated ICU 58 The numeric value may change over time, see ICU ticket #12420.
*/
UBRK_COUNT = 5
#endif // U_HIDE_DEPRECATED_API
} 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.
*
* The numeric values of all of these constants are stable (will not change).
*
* @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.
*
* The numeric values of all of these constants are stable (will not change).
*
* @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.
*
* The numeric values of all of these constants are stable (will not change).
*
* @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. Note that
* locale keys such as "lb" and "ss" may be used to modify text break behavior,
* see general discussion of BreakIterator C API.
* @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 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
* @stable 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);
/**
* Open a new UBreakIterator for locating text boundaries using precompiled binary rules.
* Opening a UBreakIterator this way is substantially faster than using ubrk_openRules.
* Binary rules may be obtained using ubrk_getBinaryRules. The compiled rules are not
* compatible across different major versions of ICU, nor across platforms of different
* endianness or different base character set family (ASCII vs EBCDIC).
* @param binaryRules A set of compiled binary rules specifying the text breaking
* conventions. Ownership of the storage containing the compiled
* rules remains with the caller of this function. The compiled
* rules must not be modified or deleted during the life of the
* break iterator.
* @param rulesLength The length of binaryRules in bytes; must be >= 0.
* @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 status Pointer to UErrorCode to receive any errors.
* @return UBreakIterator for the specified rules.
* @see ubrk_getBinaryRules
* @stable ICU 59
*/
U_CAPI UBreakIterator* U_EXPORT2
ubrk_openBinaryRules(const uint8_t *binaryRules, int32_t rulesLength,
const UChar * text, int32_t textLength,
UErrorCode * status);
#ifndef U_HIDE_DEPRECATED_API
/**
* Thread safe cloning operation
* @param bi iterator to be cloned
* @param stackBuffer Deprecated functionality as of ICU 52, use NULL.
* For word break iterators, the possible values are defined in enum UWordBreak.
* @stable ICU 2.2
*/
U_CAPI 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 attempting 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_CAPI 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_CAPI 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_CAPI void U_EXPORT2
ubrk_refreshUText(UBreakIterator *bi,
UText *text,
UErrorCode *status);
/**
* Get a compiled binary version of the rules specifying the behavior of a UBreakIterator.
* The binary rules may be used with ubrk_openBinaryRules to open a new UBreakIterator
* more quickly than using ubrk_openRules. The compiled rules are not compatible across
* different major versions of ICU, nor across platforms of different endianness or
* different base character set family (ASCII vs EBCDIC). Supports preflighting (with
* binaryRules=NULL and rulesCapacity=0) to get the rules length without copying them to
* the binaryRules buffer. However, whether preflighting or not, if the actual length
* is greater than INT32_MAX, then the function returns 0 and sets *status to
* U_INDEX_OUTOFBOUNDS_ERROR.
* @param bi The break iterator to use.
* @param binaryRules Buffer to receive the compiled binary rules; set to NULL for
* preflighting.
* @param rulesCapacity Capacity (in bytes) of the binaryRules buffer; set to 0 for
* preflighting. Must be >= 0.
* @param status Pointer to UErrorCode to receive any errors, such as
* U_BUFFER_OVERFLOW_ERROR, U_INDEX_OUTOFBOUNDS_ERROR, or
* U_ILLEGAL_ARGUMENT_ERROR.
* @return The actual byte length of the binary rules, if <= INT32_MAX;
* otherwise 0. If not preflighting and this is larger than
* rulesCapacity, *status will be set to an error.
* @see ubrk_openBinaryRules
* @stable ICU 59
*/
U_CAPI int32_t U_EXPORT2
ubrk_getBinaryRules(UBreakIterator *bi,
uint8_t * binaryRules, int32_t rulesCapacity,
UErrorCode * status);
#endif /* #if !UCONFIG_NO_BREAK_ITERATION */
#endif
* 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
* @deprecated ICU 69 Use ubrk_clone() instead.
*/
U_CAPI UBreakIterator * U_EXPORT2
ubrk_safeClone(
const UBreakIterator *bi,
void *stackBuffer,
int32_t *pBufferSize,
UErrorCode *status);
#endif /* U_HIDE_DEPRECATED_API */
#ifndef U_HIDE_DRAFT_API
/**
* Thread safe cloning operation.
* @param bi iterator to be cloned
* @param status to indicate whether the operation went on smoothly or there were errors
* @return pointer to the new clone
* @draft ICU 69
*/
U_CAPI UBreakIterator * U_EXPORT2
ubrk_clone(const UBreakIterator *bi,
UErrorCode *status);
#endif // U_HIDE_DRAFT_API
#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_CAPI 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.
* The break iterator retains a pointer to the supplied text.
* The caller must not modify or delete the text while the BreakIterator
* retains the reference.
*
* @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);
/**
* 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_CAPI 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_CAPI 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_CAPI 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_CAPI 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_CAPI 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_CAPI 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_CAPI 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_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 specified 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.
*