446 lines
15 KiB
C
446 lines
15 KiB
C
/*
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* Copyright (C) 1996-2002, International Business Machines Corporation and others. All Rights Reserved.
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*****************************************************************************************
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*/
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#ifndef UBRK_H
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#define UBRK_H
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#include "unicode/utypes.h"
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#include "unicode/parseerr.h"
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/**
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* \file
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* \brief C API: BreakIterator
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*
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* <h2> BreakIterator C API </h2>
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*
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* The BreakIterator C API defines methods for finding the location
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* of boundaries in text. Pointer to a UBreakIterator maintain a
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* current position and scan over text returning the index of characters
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* where boundaries occur.
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* <P>
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* Line boundary analysis determines where a text string can be broken
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* when line-wrapping. The mechanism correctly handles punctuation and
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* hyphenated words.
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* <P>
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* Sentence boundary analysis allows selection with correct
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* interpretation of periods within numbers and abbreviations, and
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* trailing punctuation marks such as quotation marks and parentheses.
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* <P>
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* Word boundary analysis is used by search and replace functions, as
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* well as within text editing applications that allow the user to
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* select words with a double click. Word selection provides correct
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* interpretation of punctuation marks within and following
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* words. Characters that are not part of a word, such as symbols or
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* punctuation marks, have word-breaks on both sides.
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* <P>
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* Character boundary analysis allows users to interact with
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* characters as they expect to, for example, when moving the cursor
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* through a text string. Character boundary analysis provides correct
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* navigation of through character strings, regardless of how the
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* character is stored. For example, an accented character might be
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* stored as a base character and a diacritical mark. What users
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* consider to be a character can differ between languages.
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* <P>
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* Title boundary analysis locates all positions,
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* typically starts of words, that should be set to Title Case
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* when title casing the text.
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* <P>
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*
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* This is the interface for all text boundaries.
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* <P>
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* Examples:
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* <P>
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* Helper function to output text
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* <pre>
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* \code
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* void printTextRange(UChar* str, int32_t start, int32_t end ) {
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* UChar* result;
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* UChar* temp;
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* const char* res;
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* temp=(UChar*)malloc(sizeof(UChar) * ((u_strlen(str)-start)+1));
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* result=(UChar*)malloc(sizeof(UChar) * ((end-start)+1));
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* u_strcpy(temp, &str[start]);
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* u_strncpy(result, temp, end-start);
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* res=(char*)malloc(sizeof(char) * (u_strlen(result)+1));
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* u_austrcpy(res, result);
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* printf("%s\n", res);
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* }
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* \endcode
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* </pre>
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* Print each element in order:
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* <pre>
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* \code
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* void printEachForward( UBreakIterator* boundary, UChar* str) {
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* int32_t end;
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* int32_t start = ubrk_first(boundary);
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* for (end = ubrk_next(boundary)); end != UBRK_DONE; start = end, end = ubrk_next(boundary)) {
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* printTextRange(str, start, end );
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* }
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* }
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* \endcode
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* </pre>
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* Print each element in reverse order:
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* <pre>
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* \code
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* void printEachBackward( UBreakIterator* boundary, UChar* str) {
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* int32_t start;
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* int32_t end = ubrk_last(boundary);
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* for (start = ubrk_previous(boundary); start != UBRK_DONE; end = start, start =ubrk_previous(boundary)) {
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* printTextRange( str, start, end );
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* }
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* }
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* \endcode
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* </pre>
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* Print first element
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* <pre>
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* \code
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* void printFirst(UBreakIterator* boundary, UChar* str) {
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* int32_t end;
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* int32_t start = ubrk_first(boundary);
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* end = ubrk_next(boundary);
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* printTextRange( str, start, end );
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* }
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* \endcode
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* </pre>
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* Print last element
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* <pre>
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* \code
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* void printLast(UBreakIterator* boundary, UChar* str) {
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* int32_t start;
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* int32_t end = ubrk_last(boundary);
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* start = ubrk_previous(boundary);
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* printTextRange(str, start, end );
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* }
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* \endcode
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* </pre>
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* Print the element at a specified position
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* <pre>
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* \code
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* void printAt(UBreakIterator* boundary, int32_t pos , UChar* str) {
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* int32_t start;
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* int32_t end = ubrk_following(boundary, pos);
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* start = ubrk_previous(boundary);
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* printTextRange(str, start, end );
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* }
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* \endcode
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* </pre>
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* Creating and using text boundaries
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* <pre>
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* \code
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* void BreakIterator_Example( void ) {
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* UBreakIterator* boundary;
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* UChar *stringToExamine;
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* stringToExamine=(UChar*)malloc(sizeof(UChar) * (strlen("Aaa bbb ccc. Ddd eee fff.")+1) );
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* u_uastrcpy(stringToExamine, "Aaa bbb ccc. Ddd eee fff.");
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* printf("Examining: "Aaa bbb ccc. Ddd eee fff.");
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*
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* //print each sentence in forward and reverse order
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* boundary = ubrk_open(UBRK_SENTENCE, "en_us", stringToExamine, u_strlen(stringToExamine), &status);
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* printf("----- forward: -----------\n");
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* printEachForward(boundary, stringToExamine);
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* printf("----- backward: ----------\n");
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* printEachBackward(boundary, stringToExamine);
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* ubrk_close(boundary);
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*
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* //print each word in order
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* boundary = ubrk_open(UBRK_WORD, "en_us", stringToExamine, u_strlen(stringToExamine), &status);
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* printf("----- forward: -----------\n");
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* printEachForward(boundary, stringToExamine);
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* printf("----- backward: ----------\n");
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* printEachBackward(boundary, stringToExamine);
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* //print first element
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* printf("----- first: -------------\n");
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* printFirst(boundary, stringToExamine);
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* //print last element
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* printf("----- last: --------------\n");
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* printLast(boundary, stringToExamine);
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* //print word at charpos 10
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* printf("----- at pos 10: ---------\n");
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* printAt(boundary, 10 , stringToExamine);
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*
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* ubrk_close(boundary);
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* }
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* \endcode
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* </pre>
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*/
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/**
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* A text-break iterator.
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* For usage in C programs.
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*/
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#ifndef UBRK_TYPEDEF_UBREAK_ITERATOR
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# define UBRK_TYPEDEF_UBREAK_ITERATOR
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typedef void UBreakIterator;
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#endif
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/** The possible types of text boundaries. */
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enum UBreakIteratorType {
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/** Character breaks */
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UBRK_CHARACTER,
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/** Word breaks */
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UBRK_WORD,
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/** Line breaks */
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UBRK_LINE,
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/** Sentence breaks */
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UBRK_SENTENCE,
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/** Title Case breaks */
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UBRK_TITLE
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};
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typedef enum UBreakIteratorType UBreakIteratorType;
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/** Value indicating all text boundaries have been returned.
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*
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*/
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#define UBRK_DONE ((int32_t) -1)
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/**
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* Enum constants for the word break tags returned by
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* getRuleStatus(). A range of values is defined for each category of
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* word, to allow for further subdivisions of a category in future releases.
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* Applications should check for tag values falling within the range, rather
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* than for single individual values.
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*/
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enum UWordBreak {
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UBRK_WORD_NONE = 0,
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UBRK_WORD_NONE_LIMIT = 100,
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UBRK_WORD_NUMBER = 100,
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UBRK_WORD_NUMBER_LIMIT = 200,
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UBRK_WORD_LETTER = 200,
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UBRK_WORD_LETTER_LIMIT = 300,
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UBRK_WORD_HIRAKATA = 300,
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UBRK_WORD_HIRAKATA_LIMIT = 400,
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UBRK_WORD_IDEO = 400,
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UBRK_WORD_IDEO_LIMIT = 500
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};
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typedef enum UWordBreak UWordBreak;
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/**
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* Open a new UBreakIterator for locating text boundaries for a specified locale.
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* A UBreakIterator may be used for detecting character, line, word,
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* and sentence breaks in text.
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* @param type The type of UBreakIterator to open: one of UBRK_CHARACTER, UBRK_WORD,
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* UBRK_LINE, UBRK_SENTENCE
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* @param locale The locale specifying the text-breaking conventions.
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* @param text The text to be iterated over.
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* @param textLength The number of characters in text, or -1 if null-terminated.
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* @param status A UErrorCode to receive any errors.
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* @return A UBreakIterator for the specified locale.
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* @see ubrk_openRules
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* @stable
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*/
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U_CAPI UBreakIterator* U_EXPORT2
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ubrk_open(UBreakIteratorType type,
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const char *locale,
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const UChar *text,
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int32_t textLength,
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UErrorCode *status);
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/**
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* Open a new UBreakIterator for locating text boundaries using specified breaking rules.
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* The rule syntax is ... (TBD)
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* @param rules A set of rules specifying the text breaking conventions.
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* @param rulesLength The number of characters in rules, or -1 if null-terminated.
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* @param text The text to be iterated over. May be null, in which case ubrk_setText() is
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* used to specify the text to be iterated.
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* @param textLength The number of characters in text, or -1 if null-terminated.
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* @param parseErr Receives position and context information for any syntax errors
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* detected while parsing the rules.
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* @param status A UErrorCode to receive any errors.
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* @return A UBreakIterator for the specified rules.
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* @see ubrk_open
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* @draft
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*/
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U_CAPI UBreakIterator* U_EXPORT2
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ubrk_openRules(const UChar *rules,
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int32_t rulesLength,
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const UChar *text,
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int32_t textLength,
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UParseError *parseErr,
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UErrorCode *status);
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/**
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* Thread safe cloning operation
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* @param bi iterator to be cloned
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* @param stackBuffer user allocated space for the new clone. If NULL new memory will be allocated.
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* If buffer is not large enough, new memory will be allocated.
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* Clients can use the U_BRK_SAFECLONE_BUFFERSIZE. This will probably be enough to avoid memory allocations.
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* @param pBufferSize pointer to size of allocated space.
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* If *pBufferSize == 0, a sufficient size for use in cloning will
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* be returned ('pre-flighting')
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* If *pBufferSize is not enough for a stack-based safe clone,
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* new memory will be allocated.
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* @param status to indicate whether the operation went on smoothly or there were errors
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* An informational status value, U_SAFECLONE_ALLOCATED_ERROR, is used if any allocations were necessary.
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* @return pointer to the new clone
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* @draft ICU 1.8
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*/
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U_CAPI UBreakIterator * U_EXPORT2
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ubrk_safeClone(
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const UBreakIterator *bi,
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void *stackBuffer,
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int32_t *pBufferSize,
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UErrorCode *status);
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#define U_BRK_SAFECLONE_BUFFERSIZE 512
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/**
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* Close a UBreakIterator.
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* Once closed, a UBreakIterator may no longer be used.
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* @param bi The break iterator to close.
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* @stable
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*/
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U_CAPI void U_EXPORT2
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ubrk_close(UBreakIterator *bi);
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/**
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* Sets an existing iterator to point to a new piece of text
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* @param bi The iterator to use
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* @param text The text to be set
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* @param textLength The length of the text
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* @param status The error code
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* @stable
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*/
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U_CAPI void U_EXPORT2
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ubrk_setText(UBreakIterator* bi,
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const UChar* text,
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int32_t textLength,
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UErrorCode* status);
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/**
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* Determine the most recently-returned text boundary.
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*
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* @param bi The break iterator to use.
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* @return The character index most recently returned by \Ref{ubrk_next}, \Ref{ubrk_previous},
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* \Ref{ubrk_first}, or \Ref{ubrk_last}.
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* @stable
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*/
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U_CAPI int32_t U_EXPORT2
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ubrk_current(const UBreakIterator *bi);
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/**
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* Determine the text boundary following the current text boundary.
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*
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* @param bi The break iterator to use.
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* @return The character index of the next text boundary, or UBRK_DONE
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* if all text boundaries have been returned.
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* @see ubrk_previous
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* @stable
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*/
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U_CAPI int32_t U_EXPORT2
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ubrk_next(UBreakIterator *bi);
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/**
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* Determine the text boundary preceding the current text boundary.
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*
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* @param bi The break iterator to use.
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* @return The character index of the preceding text boundary, or UBRK_DONE
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* if all text boundaries have been returned.
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* @see ubrk_next
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* @stable
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*/
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U_CAPI int32_t U_EXPORT2
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ubrk_previous(UBreakIterator *bi);
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/**
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* Determine the index of the first character in the text being scanned.
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* This is not always the same as index 0 of the text.
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* @param bi The break iterator to use.
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* @return The character index of the first character in the text being scanned.
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* @see ubrk_last
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* @stable
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*/
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U_CAPI int32_t U_EXPORT2
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ubrk_first(UBreakIterator *bi);
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/**
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* Determine the index immediately <EM>beyond</EM> the last character in the text being
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* scanned.
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* This is not the same as the last character.
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* @param bi The break iterator to use.
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* @return The character offset immediately <EM>beyond</EM> the last character in the
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* text being scanned.
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* @see ubrk_first
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* @stable
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*/
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U_CAPI int32_t U_EXPORT2
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ubrk_last(UBreakIterator *bi);
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/**
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* Determine the text boundary preceding the specified offset.
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* The value returned is always smaller than offset, or UBRK_DONE.
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* @param bi The break iterator to use.
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* @param offset The offset to begin scanning.
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* @return The text boundary preceding offset, or UBRK_DONE.
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* @see ubrk_following
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* @stable
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*/
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U_CAPI int32_t U_EXPORT2
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ubrk_preceding(UBreakIterator *bi,
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int32_t offset);
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/**
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* Determine the text boundary following the specified offset.
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* The value returned is always greater than offset, or UBRK_DONE.
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* @param bi The break iterator to use.
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* @param offset The offset to begin scanning.
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* @return The text boundary following offset, or UBRK_DONE.
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* @see ubrk_preceding
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* @stable
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*/
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U_CAPI int32_t U_EXPORT2
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ubrk_following(UBreakIterator *bi,
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int32_t offset);
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/**
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* Get a locale for which text breaking information is available.
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* A UBreakIterator in a locale returned by this function will perform the correct
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* text breaking for the locale.
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* @param index The index of the desired locale.
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* @return A locale for which number text breaking information is available, or 0 if none.
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* @see ubrk_countAvailable
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* @stable
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*/
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U_CAPI const char* U_EXPORT2
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ubrk_getAvailable(int32_t index);
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/**
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* Determine how many locales have text breaking information available.
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* This function is most useful as determining the loop ending condition for
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* calls to \Ref{ubrk_getAvailable}.
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* @return The number of locales for which text breaking information is available.
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* @see ubrk_getAvailable
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* @stable
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*/
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U_CAPI int32_t U_EXPORT2
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ubrk_countAvailable(void);
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/**
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* Returns true if the specfied position is a boundary position. As a side
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* effect, leaves the iterator pointing to the first boundary position at
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* or after "offset".
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* @param bi The break iterator to use.
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* @param offset the offset to check.
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* @return True if "offset" is a boundary position.
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*/
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U_CAPI UBool U_EXPORT2
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ubrk_isBoundary(UBreakIterator *bi, int32_t offset);
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/**
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* Return the status from the break rule that determined the most recently
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* returned break position. The values appear in the rule source
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* within brackets, {123}, for example. For rules that do not specify a
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* status, a default value of 0 is returned.
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* <p>
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* For word break iterators, the possible values are defined in enum UWordBreak.
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*/
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U_CAPI int32_t U_EXPORT2
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ubrk_getRuleStatus(UBreakIterator *bi);
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#endif
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