324 lines
12 KiB
C
324 lines
12 KiB
C
/*
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*****************************************************************************************
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* *
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* COPYRIGHT: *
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* (C) Copyright Taligent, Inc., 1996 *
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* (C) Copyright International Business Machines Corporation, 1998-1999 *
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* Licensed Material - Program-Property of IBM - All Rights Reserved. *
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* US Government Users Restricted Rights - Use, duplication, or disclosure *
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* restricted by GSA ADP Schedule Contract with IBM Corp. *
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* *
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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 "utypes.h"
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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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* 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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* . void printTextRange(UChar* str, UTextOffset start, UTextOffset end )
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* . {
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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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* </pre>
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* Print each element in order:
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* <pre>
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* . void printEachForward( UBreakIterator* boundary, UChar* str)
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* . {
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* . UTextOffset end;
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* . UTextOffset 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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* . {
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* . printTextRange(str, start, end );
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* . }
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* . }
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* </pre>
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* Print each element in reverse order:
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* <pre>
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* . void printEachBackward( UBreakIterator* boundary, UChar* str)
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* . {
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* . UTextOffset start;
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* . UTextOffset 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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* . {
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* . printTextRange( str, start, end );
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* . }
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* . }
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* </pre>
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* Print first element
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* <pre>
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* . void printFirst(UBreakIterator* boundary, UChar* str)
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* . {
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* . UTextOffset end;
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* . UTextOffset 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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* </pre>
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* Print last element
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* <pre>
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* . void printLast(UBreakIterator* boundary, UChar* str)
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* . {
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* . UTextOffset start;
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* . UTextOffset 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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* </pre>
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* Print the element at a specified position
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* <pre>
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* . void printAt(UBreakIterator* boundary, UTextOffset pos , UChar* str)
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* . {
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* . UTextOffset start;
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* . UTextOffset 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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* </pre>
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* Creating and using text boundaries
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* <pre>
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* . void BreakIterator_Example( void )
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* . {
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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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* </pre>
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*/
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/** A text-break iterator */
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typedef void* UBreakIterator;
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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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};
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typedef enum UBreakIteratorType UBreakIteratorType;
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/** Value indicating all text boundaries have been returned. */
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#define UBRK_DONE ((UTextOffset) -1)
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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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*/
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U_CAPI UBreakIterator*
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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.
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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 rules.
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* @see ubrk_open
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*/
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U_CAPI UBreakIterator*
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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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UErrorCode *status);
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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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*/
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U_CAPI void
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ubrk_close(UBreakIterator *bi);
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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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*/
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U_CAPI UTextOffset
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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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*/
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U_CAPI UTextOffset
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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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*/
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U_CAPI UTextOffset
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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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*/
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U_CAPI UTextOffset
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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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*/
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U_CAPI UTextOffset
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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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*/
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U_CAPI UTextOffset
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ubrk_preceding(UBreakIterator *bi,
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UTextOffset 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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*/
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U_CAPI UTextOffset
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ubrk_following(UBreakIterator *bi,
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UTextOffset 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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*/
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U_CAPI const char*
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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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*/
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U_CAPI int32_t
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ubrk_countAvailable(void);
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#endif
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