ICU 65.1
65.1
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C API: BreakIterator. More...
#include "unicode/utypes.h"
#include "unicode/uloc.h"
#include "unicode/utext.h"
#include "unicode/localpointer.h"
#include "unicode/parseerr.h"
Go to the source code of this file.
Namespaces | |
icu | |
File coll.h. | |
Macros | |
#define | UBRK_TYPEDEF_UBREAK_ITERATOR |
A text-break iterator. More... | |
#define | UBRK_DONE ((int32_t) -1) |
Value indicating all text boundaries have been returned. More... | |
#define | U_BRK_SAFECLONE_BUFFERSIZE 1 |
A recommended size (in bytes) for the memory buffer to be passed to ubrk_saveClone(). More... | |
Typedefs | |
typedef struct UBreakIterator | UBreakIterator |
Opaque type representing an ICU Break iterator object. More... | |
typedef enum UBreakIteratorType | UBreakIteratorType |
The possible types of text boundaries. More... | |
typedef enum UWordBreak | UWordBreak |
Enum constants for the word break tags returned by getRuleStatus(). More... | |
typedef enum ULineBreakTag | ULineBreakTag |
Enum constants for the line break tags returned by getRuleStatus(). More... | |
typedef enum USentenceBreakTag | USentenceBreakTag |
Enum constants for the sentence break tags returned by getRuleStatus(). More... | |
Enumerations | |
enum | UBreakIteratorType { UBRK_CHARACTER = 0, UBRK_WORD = 1, UBRK_LINE = 2, UBRK_SENTENCE = 3, UBRK_TITLE = 4, UBRK_COUNT = 5 } |
The possible types of text boundaries. More... | |
enum | UWordBreak { UBRK_WORD_NONE = 0, UBRK_WORD_NONE_LIMIT = 100, UBRK_WORD_NUMBER = 100, UBRK_WORD_NUMBER_LIMIT = 200, UBRK_WORD_LETTER = 200, UBRK_WORD_LETTER_LIMIT = 300, UBRK_WORD_KANA = 300, UBRK_WORD_KANA_LIMIT = 400, UBRK_WORD_IDEO = 400, UBRK_WORD_IDEO_LIMIT = 500 } |
Enum constants for the word break tags returned by getRuleStatus(). More... | |
enum | ULineBreakTag { UBRK_LINE_SOFT = 0, UBRK_LINE_SOFT_LIMIT = 100, UBRK_LINE_HARD = 100, UBRK_LINE_HARD_LIMIT = 200 } |
Enum constants for the line break tags returned by getRuleStatus(). More... | |
enum | USentenceBreakTag { UBRK_SENTENCE_TERM = 0, UBRK_SENTENCE_TERM_LIMIT = 100, UBRK_SENTENCE_SEP = 100, UBRK_SENTENCE_SEP_LIMIT = 200 } |
Enum constants for the sentence break tags returned by getRuleStatus(). More... | |
Functions | |
UBreakIterator * | ubrk_open (UBreakIteratorType type, const char *locale, const UChar *text, int32_t textLength, UErrorCode *status) |
Open a new UBreakIterator for locating text boundaries for a specified locale. More... | |
UBreakIterator * | 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 specified breaking rules. More... | |
UBreakIterator * | ubrk_openBinaryRules (const uint8_t *binaryRules, int32_t rulesLength, const UChar *text, int32_t textLength, UErrorCode *status) |
Open a new UBreakIterator for locating text boundaries using precompiled binary rules. More... | |
UBreakIterator * | ubrk_safeClone (const UBreakIterator *bi, void *stackBuffer, int32_t *pBufferSize, UErrorCode *status) |
Thread safe cloning operation. More... | |
void | ubrk_close (UBreakIterator *bi) |
Close a UBreakIterator. More... | |
void | ubrk_setText (UBreakIterator *bi, const UChar *text, int32_t textLength, UErrorCode *status) |
Sets an existing iterator to point to a new piece of text. More... | |
void | ubrk_setUText (UBreakIterator *bi, UText *text, UErrorCode *status) |
Sets an existing iterator to point to a new piece of text. More... | |
int32_t | ubrk_current (const UBreakIterator *bi) |
Determine the most recently-returned text boundary. More... | |
int32_t | ubrk_next (UBreakIterator *bi) |
Advance the iterator to the boundary following the current boundary. More... | |
int32_t | ubrk_previous (UBreakIterator *bi) |
Set the iterator position to the boundary preceding the current boundary. More... | |
int32_t | ubrk_first (UBreakIterator *bi) |
Set the iterator position to zero, the start of the text being scanned. More... | |
int32_t | ubrk_last (UBreakIterator *bi) |
Set the iterator position to the index immediately beyond the last character in the text being scanned. More... | |
int32_t | ubrk_preceding (UBreakIterator *bi, int32_t offset) |
Set the iterator position to the first boundary preceding the specified offset. More... | |
int32_t | ubrk_following (UBreakIterator *bi, int32_t offset) |
Advance the iterator to the first boundary following the specified offset. More... | |
const char * | ubrk_getAvailable (int32_t index) |
Get a locale for which text breaking information is available. More... | |
int32_t | ubrk_countAvailable (void) |
Determine how many locales have text breaking information available. More... | |
UBool | ubrk_isBoundary (UBreakIterator *bi, int32_t offset) |
Returns true if the specified position is a boundary position. More... | |
int32_t | ubrk_getRuleStatus (UBreakIterator *bi) |
Return the status from the break rule that determined the most recently returned break position. More... | |
int32_t | ubrk_getRuleStatusVec (UBreakIterator *bi, int32_t *fillInVec, int32_t capacity, UErrorCode *status) |
Get the statuses from the break rules that determined the most recently returned break position. More... | |
const char * | ubrk_getLocaleByType (const UBreakIterator *bi, ULocDataLocaleType type, UErrorCode *status) |
Return the locale of the break iterator. More... | |
void | ubrk_refreshUText (UBreakIterator *bi, UText *text, UErrorCode *status) |
Set the subject text string upon which the break iterator is operating without changing any other aspect of the state. More... | |
int32_t | ubrk_getBinaryRules (UBreakIterator *bi, uint8_t *binaryRules, int32_t rulesCapacity, UErrorCode *status) |
Get a compiled binary version of the rules specifying the behavior of a UBreakIterator. More... | |
C API: BreakIterator.
The BreakIterator C API defines methods for finding the location of boundaries in text. Pointer to a UBreakIterator maintain a current position and scan over text returning the index of characters where boundaries occur.
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 http://dev.w3.org/csswg/css-text/#line-breaking. For example: "ja@lb=strict", "zh@lb=loose".
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, http://icu-project.org/userguide/boundaryAnalysis.html and in the sample program icu/source/samples/break/break.cpp
Definition in file ubrk.h.
#define U_BRK_SAFECLONE_BUFFERSIZE 1 |
A recommended size (in bytes) for the memory buffer to be passed to ubrk_saveClone().
#define UBRK_DONE ((int32_t) -1) |
#define UBRK_TYPEDEF_UBREAK_ITERATOR |
typedef struct UBreakIterator UBreakIterator |
typedef enum UBreakIteratorType UBreakIteratorType |
The possible types of text boundaries.
typedef enum ULineBreakTag ULineBreakTag |
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).
typedef enum USentenceBreakTag USentenceBreakTag |
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).
typedef enum UWordBreak UWordBreak |
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).
enum UBreakIteratorType |
The possible types of text boundaries.
Enumerator | |
---|---|
UBRK_CHARACTER | Character breaks.
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UBRK_WORD | Word breaks.
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UBRK_LINE | Line breaks.
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UBRK_SENTENCE | Sentence breaks.
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UBRK_TITLE | 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.
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UBRK_COUNT | One more than the highest normal UBreakIteratorType value.
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enum ULineBreakTag |
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).
enum USentenceBreakTag |
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).
enum UWordBreak |
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).
void ubrk_close | ( | UBreakIterator * | bi | ) |
Close a UBreakIterator.
Once closed, a UBreakIterator may no longer be used.
bi | The break iterator to close. |
int32_t ubrk_countAvailable | ( | void | ) |
Determine how many locales have text breaking information available.
This function is most useful as determining the loop ending condition for calls to ubrk_getAvailable.
int32_t ubrk_current | ( | const UBreakIterator * | bi | ) |
Determine the most recently-returned text boundary.
bi | The break iterator to use. |
int32_t ubrk_first | ( | UBreakIterator * | bi | ) |
int32_t ubrk_following | ( | 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.
bi | The break iterator to use. |
offset | The offset to begin scanning. |
const char* ubrk_getAvailable | ( | int32_t | index | ) |
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.
index | The index of the desired locale. |
int32_t ubrk_getBinaryRules | ( | UBreakIterator * | bi, |
uint8_t * | binaryRules, | ||
int32_t | rulesCapacity, | ||
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.
bi | The break iterator to use. |
binaryRules | Buffer to receive the compiled binary rules; set to NULL for preflighting. |
rulesCapacity | Capacity (in bytes) of the binaryRules buffer; set to 0 for preflighting. Must be >= 0. |
status | Pointer to UErrorCode to receive any errors, such as U_BUFFER_OVERFLOW_ERROR, U_INDEX_OUTOFBOUNDS_ERROR, or U_ILLEGAL_ARGUMENT_ERROR. |
const char* ubrk_getLocaleByType | ( | const UBreakIterator * | bi, |
ULocDataLocaleType | type, | ||
UErrorCode * | status | ||
) |
Return the locale of the break iterator.
You can choose between the valid and the actual locale.
bi | break iterator |
type | locale type (valid or actual) |
status | error code |
int32_t ubrk_getRuleStatus | ( | UBreakIterator * | bi | ) |
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.
int32_t ubrk_getRuleStatusVec | ( | UBreakIterator * | bi, |
int32_t * | fillInVec, | ||
int32_t | capacity, | ||
UErrorCode * | status | ||
) |
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.
bi | The break iterator to use |
fillInVec | an array to be filled in with the status values. |
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. |
status | receives error codes. |
UBool ubrk_isBoundary | ( | UBreakIterator * | bi, |
int32_t | offset | ||
) |
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".
bi | The break iterator to use. |
offset | the offset to check. |
int32_t ubrk_last | ( | 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.
bi | The break iterator to use. |
int32_t ubrk_next | ( | UBreakIterator * | bi | ) |
Advance the iterator to the boundary following the current boundary.
bi | The break iterator to use. |
UBreakIterator* ubrk_open | ( | UBreakIteratorType | type, |
const char * | locale, | ||
const UChar * | text, | ||
int32_t | textLength, | ||
UErrorCode * | status | ||
) |
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.
type | The type of UBreakIterator to open: one of UBRK_CHARACTER, UBRK_WORD, UBRK_LINE, UBRK_SENTENCE |
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. |
text | The text to be iterated over. May be null, in which case ubrk_setText() is used to specify the text to be iterated. |
textLength | The number of characters in text, or -1 if null-terminated. |
status | A UErrorCode to receive any errors. |
UBreakIterator* ubrk_openBinaryRules | ( | const uint8_t * | binaryRules, |
int32_t | rulesLength, | ||
const UChar * | text, | ||
int32_t | textLength, | ||
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).
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. |
rulesLength | The length of binaryRules in bytes; must be >= 0. |
text | The text to be iterated over. May be null, in which case ubrk_setText() is used to specify the text to be iterated. |
textLength | The number of characters in text, or -1 if null-terminated. |
status | Pointer to UErrorCode to receive any errors. |
UBreakIterator* 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 specified breaking rules.
The rule syntax is ... (TBD)
rules | A set of rules specifying the text breaking conventions. |
rulesLength | The number of characters in rules, or -1 if null-terminated. |
text | The text to be iterated over. May be null, in which case ubrk_setText() is used to specify the text to be iterated. |
textLength | The number of characters in text, or -1 if null-terminated. |
parseErr | Receives position and context information for any syntax errors detected while parsing the rules. |
status | A UErrorCode to receive any errors. |
int32_t ubrk_preceding | ( | UBreakIterator * | bi, |
int32_t | offset | ||
) |
Set the iterator position to the first boundary preceding the specified offset.
The new position is always smaller than offset, or UBRK_DONE.
bi | The break iterator to use. |
offset | The offset to begin scanning. |
int32_t ubrk_previous | ( | UBreakIterator * | bi | ) |
void ubrk_refreshUText | ( | UBreakIterator * | bi, |
UText * | text, | ||
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.
bi | The break iterator. |
text | The new (moved) text string. |
status | Receives errors detected by this function. |
UBreakIterator* ubrk_safeClone | ( | const UBreakIterator * | bi, |
void * | stackBuffer, | ||
int32_t * | pBufferSize, | ||
UErrorCode * | status | ||
) |
Thread safe cloning operation.
bi | iterator to be cloned |
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. |
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. |
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. |
void ubrk_setText | ( | UBreakIterator * | bi, |
const UChar * | text, | ||
int32_t | textLength, | ||
UErrorCode * | status | ||
) |
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.
bi | The iterator to use |
text | The text to be set |
textLength | The length of the text |
status | The error code |
void ubrk_setUText | ( | UBreakIterator * | bi, |
UText * | text, | ||
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 ubrk_next, ubrk_previous, etc. will be UTF-8 string indices, not UTF-16 positions.
bi | The iterator to use |
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. |
status | The error code |