1189 lines
44 KiB
C
1189 lines
44 KiB
C
/*
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******************************************************************************
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*
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* Copyright (C) 1999-2004, International Business Machines
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* Corporation and others. All Rights Reserved.
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*
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******************************************************************************
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* file name: ubidi.h
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* encoding: US-ASCII
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* tab size: 8 (not used)
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* indentation:4
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*
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* created on: 1999jul27
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* created by: Markus W. Scherer
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*/
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#ifndef UBIDI_H
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#define UBIDI_H
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#include "unicode/utypes.h"
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#include "unicode/uchar.h"
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/*
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* javadoc-style comments are intended to be transformed into HTML
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* using DOC++ - see
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* http://www.zib.de/Visual/software/doc++/index.html .
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*
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* The HTML documentation is created with
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* doc++ -H ubidi.h
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*
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* The following #define trick allows us to do it all in one file
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* and still be able to compile it.
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*/
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/*#define DOCXX_TAG*/
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/*#define BIDI_SAMPLE_CODE*/
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/**
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*\file
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* \brief C API: BIDI algorithm
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*
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* <h2>BIDI algorithm for ICU</h2>
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*
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* This is an implementation of the Unicode Bidirectional algorithm.
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* The algorithm is defined in the
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* <a href="http://www.unicode.org/unicode/reports/tr9/">Unicode Standard Annex #9</a>,
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* version 13, also described in The Unicode Standard, Version 4.0 .<p>
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*
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* Note: Libraries that perform a bidirectional algorithm and
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* reorder strings accordingly are sometimes called "Storage Layout Engines".
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* ICU's BiDi and shaping (u_shapeArabic()) APIs can be used at the core of such
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* "Storage Layout Engines".
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*
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* <h3>General remarks about the API:</h3>
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*
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* In functions with an error code parameter,
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* the <code>pErrorCode</code> pointer must be valid
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* and the value that it points to must not indicate a failure before
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* the function call. Otherwise, the function returns immediately.
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* After the function call, the value indicates success or failure.<p>
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*
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* The "limit" of a sequence of characters is the position just after their
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* last character, i.e., one more than that position.<p>
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*
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* Some of the API functions provide access to "runs".
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* Such a "run" is defined as a sequence of characters
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* that are at the same embedding level
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* after performing the BIDI algorithm.<p>
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*
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* @author Markus W. Scherer
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* @version 1.0
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*
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*
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* <h4> Sample code for the ICU BIDI API </h4>
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*
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* <h5>Rendering a paragraph with the ICU BiDi API</h5>
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*
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* This is (hypothetical) sample code that illustrates
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* how the ICU BiDi API could be used to render a paragraph of text.
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* Rendering code depends highly on the graphics system,
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* therefore this sample code must make a lot of assumptions,
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* which may or may not match any existing graphics system's properties.
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*
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* <p>The basic assumptions are:</p>
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* <ul>
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* <li>Rendering is done from left to right on a horizontal line.</li>
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* <li>A run of single-style, unidirectional text can be rendered at once.</li>
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* <li>Such a run of text is passed to the graphics system with
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* characters (code units) in logical order.</li>
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* <li>The line-breaking algorithm is very complicated
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* and Locale-dependent -
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* and therefore its implementation omitted from this sample code.</li>
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* </ul>
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*
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* <pre>
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* \code
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*#include "unicode/ubidi.h"
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*
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*typedef enum {
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* styleNormal=0, styleSelected=1,
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* styleBold=2, styleItalics=4,
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* styleSuper=8, styleSub=16
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*} Style;
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*
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*typedef struct { int32_t limit; Style style; } StyleRun;
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*
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*int getTextWidth(const UChar *text, int32_t start, int32_t limit,
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* const StyleRun *styleRuns, int styleRunCount);
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*
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* // set *pLimit and *pStyleRunLimit for a line
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* // from text[start] and from styleRuns[styleRunStart]
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* // using ubidi_getLogicalRun(para, ...)
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*void getLineBreak(const UChar *text, int32_t start, int32_t *pLimit,
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* UBiDi *para,
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* const StyleRun *styleRuns, int styleRunStart, int *pStyleRunLimit,
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* int *pLineWidth);
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*
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* // render runs on a line sequentially, always from left to right
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*
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* // prepare rendering a new line
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* void startLine(UBiDiDirection textDirection, int lineWidth);
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*
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* // render a run of text and advance to the right by the run width
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* // the text[start..limit-1] is always in logical order
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* void renderRun(const UChar *text, int32_t start, int32_t limit,
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* UBiDiDirection textDirection, Style style);
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*
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* // We could compute a cross-product
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* // from the style runs with the directional runs
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* // and then reorder it.
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* // Instead, here we iterate over each run type
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* // and render the intersections -
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* // with shortcuts in simple (and common) cases.
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* // renderParagraph() is the main function.
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*
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* // render a directional run with
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* // (possibly) multiple style runs intersecting with it
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* void renderDirectionalRun(const UChar *text,
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* int32_t start, int32_t limit,
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* UBiDiDirection direction,
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* const StyleRun *styleRuns, int styleRunCount) {
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* int i;
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*
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* // iterate over style runs
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* if(direction==UBIDI_LTR) {
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* int styleLimit;
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*
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* for(i=0; i<styleRunCount; ++i) {
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* styleLimit=styleRun[i].limit;
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* if(start<styleLimit) {
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* if(styleLimit>limit) { styleLimit=limit; }
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* renderRun(text, start, styleLimit,
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* direction, styleRun[i].style);
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* if(styleLimit==limit) { break; }
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* start=styleLimit;
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* }
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* }
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* } else {
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* int styleStart;
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*
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* for(i=styleRunCount-1; i>=0; --i) {
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* if(i>0) {
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* styleStart=styleRun[i-1].limit;
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* } else {
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* styleStart=0;
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* }
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* if(limit>=styleStart) {
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* if(styleStart<start) { styleStart=start; }
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* renderRun(text, styleStart, limit,
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* direction, styleRun[i].style);
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* if(styleStart==start) { break; }
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* limit=styleStart;
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* }
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* }
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* }
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* }
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*
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* // the line object represents text[start..limit-1]
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* void renderLine(UBiDi *line, const UChar *text,
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* int32_t start, int32_t limit,
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* const StyleRun *styleRuns, int styleRunCount) {
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* UBiDiDirection direction=ubidi_getDirection(line);
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* if(direction!=UBIDI_MIXED) {
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* // unidirectional
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* if(styleRunCount<=1) {
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* renderRun(text, start, limit, direction, styleRuns[0].style);
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* } else {
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* renderDirectionalRun(text, start, limit,
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* direction, styleRuns, styleRunCount);
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* }
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* } else {
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* // mixed-directional
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* int32_t count, i, length;
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* UBiDiLevel level;
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*
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* count=ubidi_countRuns(para, pErrorCode);
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* if(U_SUCCESS(*pErrorCode)) {
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* if(styleRunCount<=1) {
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* Style style=styleRuns[0].style;
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*
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* // iterate over directional runs
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* for(i=0; i<count; ++i) {
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* direction=ubidi_getVisualRun(para, i, &start, &length);
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* renderRun(text, start, start+length, direction, style);
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* }
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* } else {
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* int32_t j;
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*
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* // iterate over both directional and style runs
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* for(i=0; i<count; ++i) {
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* direction=ubidi_getVisualRun(line, i, &start, &length);
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* renderDirectionalRun(text, start, start+length,
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* direction, styleRuns, styleRunCount);
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* }
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* }
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* }
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* }
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* }
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*
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*void renderParagraph(const UChar *text, int32_t length,
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* UBiDiDirection textDirection,
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* const StyleRun *styleRuns, int styleRunCount,
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* int lineWidth,
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* UErrorCode *pErrorCode) {
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* UBiDi *para;
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*
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* if(pErrorCode==NULL || U_FAILURE(*pErrorCode) || length<=0) {
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* return;
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* }
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*
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* para=ubidi_openSized(length, 0, pErrorCode);
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* if(para==NULL) { return; }
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*
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* ubidi_setPara(para, text, length,
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* textDirection ? UBIDI_DEFAULT_RTL : UBIDI_DEFAULT_LTR,
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* NULL, pErrorCode);
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* if(U_SUCCESS(*pErrorCode)) {
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* UBiDiLevel paraLevel=1&ubidi_getParaLevel(para);
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* StyleRun styleRun={ length, styleNormal };
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* int width;
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*
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* if(styleRuns==NULL || styleRunCount<=0) {
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* styleRunCount=1;
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* styleRuns=&styleRun;
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* }
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*
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* // assume styleRuns[styleRunCount-1].limit>=length
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*
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* width=getTextWidth(text, 0, length, styleRuns, styleRunCount);
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* if(width<=lineWidth) {
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* // everything fits onto one line
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*
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* // prepare rendering a new line from either left or right
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* startLine(paraLevel, width);
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*
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* renderLine(para, text, 0, length,
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* styleRuns, styleRunCount);
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* } else {
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* UBiDi *line;
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*
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* // we need to render several lines
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* line=ubidi_openSized(length, 0, pErrorCode);
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* if(line!=NULL) {
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* int32_t start=0, limit;
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* int styleRunStart=0, styleRunLimit;
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*
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* for(;;) {
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* limit=length;
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* styleRunLimit=styleRunCount;
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* getLineBreak(text, start, &limit, para,
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* styleRuns, styleRunStart, &styleRunLimit,
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* &width);
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* ubidi_setLine(para, start, limit, line, pErrorCode);
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* if(U_SUCCESS(*pErrorCode)) {
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* // prepare rendering a new line
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* // from either left or right
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* startLine(paraLevel, width);
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*
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* renderLine(line, text, start, limit,
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* styleRuns+styleRunStart,
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* styleRunLimit-styleRunStart);
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* }
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* if(limit==length) { break; }
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* start=limit;
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* styleRunStart=styleRunLimit-1;
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* if(start>=styleRuns[styleRunStart].limit) {
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* ++styleRunStart;
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* }
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* }
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*
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* ubidi_close(line);
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* }
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* }
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* }
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*
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* ubidi_close(para);
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*}
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*\endcode
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* </pre>
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*/
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/*DOCXX_TAG*/
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/*@{*/
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/**
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* UBiDiLevel is the type of the level values in this
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* BiDi implementation.
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* It holds an embedding level and indicates the visual direction
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* by its bit 0 (even/odd value).<p>
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*
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* It can also hold non-level values for the
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* <code>paraLevel</code> and <code>embeddingLevels</code>
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* arguments of <code>ubidi_setPara()</code>; there:
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* <ul>
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* <li>bit 7 of an <code>embeddingLevels[]</code>
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* value indicates whether the using application is
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* specifying the level of a character to <i>override</i> whatever the
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* BiDi implementation would resolve it to.</li>
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* <li><code>paraLevel</code> can be set to the
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* pseudo-level values <code>UBIDI_DEFAULT_LTR</code>
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* and <code>UBIDI_DEFAULT_RTL</code>.</li>
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* </ul>
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*
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* @see ubidi_setPara
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*
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* <p>The related constants are not real, valid level values.
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* <code>UBIDI_DEFAULT_XXX</code> can be used to specify
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* a default for the paragraph level for
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* when the <code>ubidi_setPara()</code> function
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* shall determine it but there is no
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* strongly typed character in the input.<p>
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*
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* Note that the value for <code>UBIDI_DEFAULT_LTR</code> is even
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* and the one for <code>UBIDI_DEFAULT_RTL</code> is odd,
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* just like with normal LTR and RTL level values -
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* these special values are designed that way. Also, the implementation
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* assumes that UBIDI_MAX_EXPLICIT_LEVEL is odd.
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*
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* @see UBIDI_DEFAULT_LTR
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* @see UBIDI_DEFAULT_RTL
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* @see UBIDI_LEVEL_OVERRIDE
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* @see UBIDI_MAX_EXPLICIT_LEVEL
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* @stable ICU 2.0
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*/
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typedef uint8_t UBiDiLevel;
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/** Paragraph level setting.
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* If there is no strong character, then set the paragraph level to 0 (left-to-right).
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* @stable ICU 2.0
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*/
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#define UBIDI_DEFAULT_LTR 0xfe
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/** Paragraph level setting.
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* If there is no strong character, then set the paragraph level to 1 (right-to-left).
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* @stable ICU 2.0
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*/
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#define UBIDI_DEFAULT_RTL 0xff
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/**
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* Maximum explicit embedding level.
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* (The maximum resolved level can be up to <code>UBIDI_MAX_EXPLICIT_LEVEL+1</code>).
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* @stable ICU 2.0
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*/
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#define UBIDI_MAX_EXPLICIT_LEVEL 61
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/** Bit flag for level input.
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* Overrides directional properties.
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* @stable ICU 2.0
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*/
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#define UBIDI_LEVEL_OVERRIDE 0x80
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/**
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* @memo <code>UBiDiDirection</code> values indicate the text direction.
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* @stable ICU 2.0
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*/
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enum UBiDiDirection {
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/** @memo All left-to-right text. This is a 0 value. @stable ICU 2.0 */
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UBIDI_LTR,
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/** @memo All right-to-left text. This is a 1 value. @stable ICU 2.0 */
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UBIDI_RTL,
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/** @memo Mixed-directional text. @stable ICU 2.0 */
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UBIDI_MIXED
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};
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/** @stable ICU 2.0 */
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typedef enum UBiDiDirection UBiDiDirection;
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/**
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* Forward declaration of the <code>UBiDi</code> structure for the declaration of
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* the API functions. Its fields are implementation-specific.<p>
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* This structure holds information about a paragraph of text
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* with BiDi-algorithm-related details, or about one line of
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* such a paragraph.<p>
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* Reordering can be done on a line, or on a paragraph which is
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* then interpreted as one single line.
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* @stable ICU 2.0
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*/
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struct UBiDi;
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/** @stable ICU 2.0 */
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typedef struct UBiDi UBiDi;
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/**
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* Allocate a <code>UBiDi</code> structure.
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* Such an object is initially empty. It is assigned
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* the BiDi properties of a paragraph by <code>ubidi_setPara()</code>
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* or the BiDi properties of a line of a paragraph by
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* <code>ubidi_setLine()</code>.<p>
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* This object can be reused for as long as it is not deallocated
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* by calling <code>ubidi_close()</code>.<p>
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* <code>ubidi_set()</code> will allocate additional memory for
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* internal structures as necessary.
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*
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* @return An empty <code>UBiDi</code> object.
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* @stable ICU 2.0
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*/
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U_STABLE UBiDi * U_EXPORT2
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ubidi_open(void);
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/**
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* Allocate a <code>UBiDi</code> structure with preallocated memory
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* for internal structures.
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* This function provides a <code>UBiDi</code> object like <code>ubidi_open()</code>
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* with no arguments, but it also preallocates memory for internal structures
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* according to the sizings supplied by the caller.<p>
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* Subsequent functions will not allocate any more memory, and are thus
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* guaranteed not to fail because of lack of memory.<p>
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* The preallocation can be limited to some of the internal memory
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* by setting some values to 0 here. That means that if, e.g.,
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* <code>maxRunCount</code> cannot be reasonably predetermined and should not
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* be set to <code>maxLength</code> (the only failproof value) to avoid
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* wasting memory, then <code>maxRunCount</code> could be set to 0 here
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* and the internal structures that are associated with it will be allocated
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* on demand, just like with <code>ubidi_open()</code>.
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*
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* @param maxLength is the maximum paragraph or line length that internal memory
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* will be preallocated for. An attempt to associate this object with a
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* longer text will fail, unless this value is 0, which leaves the allocation
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* up to the implementation.
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*
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* @param maxRunCount is the maximum anticipated number of same-level runs
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* that internal memory will be preallocated for. An attempt to access
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* visual runs on an object that was not preallocated for as many runs
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* as the text was actually resolved to will fail,
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* unless this value is 0, which leaves the allocation up to the implementation.<p>
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* The number of runs depends on the actual text and maybe anywhere between
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* 1 and <code>maxLength</code>. It is typically small.<p>
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*
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* @param pErrorCode must be a valid pointer to an error code value,
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* which must not indicate a failure before the function call.
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*
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* @return An empty <code>UBiDi</code> object with preallocated memory.
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* @stable ICU 2.0
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*/
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U_STABLE UBiDi * U_EXPORT2
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ubidi_openSized(int32_t maxLength, int32_t maxRunCount, UErrorCode *pErrorCode);
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/**
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* <code>ubidi_close()</code> must be called to free the memory
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* associated with a UBiDi object.<p>
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*
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* <strong>Important: </strong>
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* A parent <code>UBiDi</code> object must not be destroyed or reused if
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* it still has children.
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* If a <code>UBiDi</code> object is the <i>child</i>
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* of another one (its <i>parent</i>), after calling
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* <code>ubidi_setLine()</code>, then the child object must
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* be destroyed (closed) or reused (by calling
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* <code>ubidi_setPara()</code> or <code>ubidi_setLine()</code>)
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* before the parent object.
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*
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* @param pBiDi is a <code>UBiDi</code> object.
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*
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* @see ubidi_setPara
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* @see ubidi_setLine
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* @stable ICU 2.0
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*/
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U_STABLE void U_EXPORT2
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ubidi_close(UBiDi *pBiDi);
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/**
|
|
* Modify the operation of the BiDi algorithm such that it
|
|
* approximates an "inverse BiDi" algorithm. This function
|
|
* must be called before <code>ubidi_setPara()</code>.
|
|
*
|
|
* <p>The normal operation of the BiDi algorithm as described
|
|
* in the Unicode Technical Report is to take text stored in logical
|
|
* (keyboard, typing) order and to determine the reordering of it for visual
|
|
* rendering.
|
|
* Some legacy systems store text in visual order, and for operations
|
|
* with standard, Unicode-based algorithms, the text needs to be transformed
|
|
* to logical order. This is effectively the inverse algorithm of the
|
|
* described BiDi algorithm. Note that there is no standard algorithm for
|
|
* this "inverse BiDi" and that the current implementation provides only an
|
|
* approximation of "inverse BiDi".</p>
|
|
*
|
|
* <p>With <code>isInverse</code> set to <code>TRUE</code>,
|
|
* this function changes the behavior of some of the subsequent functions
|
|
* in a way that they can be used for the inverse BiDi algorithm.
|
|
* Specifically, runs of text with numeric characters will be treated in a
|
|
* special way and may need to be surrounded with LRM characters when they are
|
|
* written in reordered sequence.</p>
|
|
*
|
|
* <p>Output runs should be retrieved using <code>ubidi_getVisualRun()</code>.
|
|
* Since the actual input for "inverse BiDi" is visually ordered text and
|
|
* <code>ubidi_getVisualRun()</code> gets the reordered runs, these are actually
|
|
* the runs of the logically ordered output.</p>
|
|
*
|
|
* @param pBiDi is a <code>UBiDi</code> object.
|
|
*
|
|
* @param isInverse specifies "forward" or "inverse" BiDi operation
|
|
*
|
|
* @see ubidi_setPara
|
|
* @see ubidi_writeReordered
|
|
* @stable ICU 2.0
|
|
*/
|
|
U_STABLE void U_EXPORT2
|
|
ubidi_setInverse(UBiDi *pBiDi, UBool isInverse);
|
|
|
|
/**
|
|
* Is this BiDi object set to perform the inverse BiDi algorithm?
|
|
*
|
|
* @param pBiDi is a <code>UBiDi</code> object.
|
|
* @return TRUE if the BiDi object set to perform the inverse BiDi algorithm
|
|
*
|
|
* @see ubidi_setInverse
|
|
* @stable ICU 2.0
|
|
*/
|
|
U_STABLE UBool U_EXPORT2
|
|
ubidi_isInverse(UBiDi *pBiDi);
|
|
|
|
/**
|
|
* Perform the Unicode BiDi algorithm. It is defined in the
|
|
* <a href="http://www.unicode.org/unicode/reports/tr9/">Unicode Standard Anned #9</a>,
|
|
* version 13,
|
|
* also described in The Unicode Standard, Version 4.0 .<p>
|
|
*
|
|
* This function takes a single plain text paragraph with or without
|
|
* externally specified embedding levels from <i>styled</i> text
|
|
* and computes the left-right-directionality of each character.<p>
|
|
*
|
|
* If the entire paragraph consists of text of only one direction, then
|
|
* the function may not perform all the steps described by the algorithm,
|
|
* i.e., some levels may not be the same as if all steps were performed.
|
|
* This is not relevant for unidirectional text.<br>
|
|
* For example, in pure LTR text with numbers the numbers would get
|
|
* a resolved level of 2 higher than the surrounding text according to
|
|
* the algorithm. This implementation may set all resolved levels to
|
|
* the same value in such a case.<p>
|
|
*
|
|
* The text must be externally split into separate paragraphs (rule P1).
|
|
* Paragraph separators (B) should appear at most at the very end.
|
|
*
|
|
* @param pBiDi A <code>UBiDi</code> object allocated with <code>ubidi_open()</code>
|
|
* which will be set to contain the reordering information,
|
|
* especially the resolved levels for all the characters in <code>text</code>.
|
|
*
|
|
* @param text is a pointer to the single-paragraph text that the
|
|
* BiDi algorithm will be performed on
|
|
* (step (P1) of the algorithm is performed externally).
|
|
* <strong>The text must be (at least) <code>length</code> long.</strong>
|
|
* This pointer is stored in the UBiDi object and can be retrieved
|
|
* with <code>ubidi_getText()</code>.
|
|
*
|
|
* @param length is the length of the text; if <code>length==-1</code> then
|
|
* the text must be zero-terminated.
|
|
*
|
|
* @param paraLevel specifies the default level for the paragraph;
|
|
* it is typically 0 (LTR) or 1 (RTL).
|
|
* If the function shall determine the paragraph level from the text,
|
|
* then <code>paraLevel</code> can be set to
|
|
* either <code>UBIDI_DEFAULT_LTR</code>
|
|
* or <code>UBIDI_DEFAULT_RTL</code>;
|
|
* if there is no strongly typed character, then
|
|
* the desired default is used (0 for LTR or 1 for RTL).
|
|
* Any other value between 0 and <code>UBIDI_MAX_EXPLICIT_LEVEL</code> is also valid,
|
|
* with odd levels indicating RTL.
|
|
*
|
|
* @param embeddingLevels (in) may be used to preset the embedding and override levels,
|
|
* ignoring characters like LRE and PDF in the text.
|
|
* A level overrides the directional property of its corresponding
|
|
* (same index) character if the level has the
|
|
* <code>UBIDI_LEVEL_OVERRIDE</code> bit set.<p>
|
|
* Except for that bit, it must be
|
|
* <code>paraLevel<=embeddingLevels[]<=UBIDI_MAX_EXPLICIT_LEVEL</code>.<p>
|
|
* <strong>Caution: </strong>A copy of this pointer, not of the levels,
|
|
* will be stored in the <code>UBiDi</code> object;
|
|
* the <code>embeddingLevels</code> array must not be
|
|
* deallocated before the <code>UBiDi</code> structure is destroyed or reused,
|
|
* and the <code>embeddingLevels</code>
|
|
* should not be modified to avoid unexpected results on subsequent BiDi operations.
|
|
* However, the <code>ubidi_setPara()</code> and
|
|
* <code>ubidi_setLine()</code> functions may modify some or all of the levels.<p>
|
|
* After the <code>UBiDi</code> object is reused or destroyed, the caller
|
|
* must take care of the deallocation of the <code>embeddingLevels</code> array.<p>
|
|
* <strong>The <code>embeddingLevels</code> array must be
|
|
* at least <code>length</code> long.</strong>
|
|
*
|
|
* @param pErrorCode must be a valid pointer to an error code value,
|
|
* which must not indicate a failure before the function call.
|
|
* @stable ICU 2.0
|
|
*/
|
|
U_STABLE void U_EXPORT2
|
|
ubidi_setPara(UBiDi *pBiDi, const UChar *text, int32_t length,
|
|
UBiDiLevel paraLevel, UBiDiLevel *embeddingLevels,
|
|
UErrorCode *pErrorCode);
|
|
|
|
/**
|
|
* <code>ubidi_setLine()</code> sets a <code>UBiDi</code> to
|
|
* contain the reordering information, especially the resolved levels,
|
|
* for all the characters in a line of text. This line of text is
|
|
* specified by referring to a <code>UBiDi</code> object representing
|
|
* this information for a paragraph of text, and by specifying
|
|
* a range of indexes in this paragraph.<p>
|
|
* In the new line object, the indexes will range from 0 to <code>limit-start-1</code>.<p>
|
|
*
|
|
* This is used after calling <code>ubidi_setPara()</code>
|
|
* for a paragraph, and after line-breaking on that paragraph.
|
|
* It is not necessary if the paragraph is treated as a single line.<p>
|
|
*
|
|
* After line-breaking, rules (L1) and (L2) for the treatment of
|
|
* trailing WS and for reordering are performed on
|
|
* a <code>UBiDi</code> object that represents a line.<p>
|
|
*
|
|
* <strong>Important: </strong><code>pLineBiDi</code> shares data with
|
|
* <code>pParaBiDi</code>.
|
|
* You must destroy or reuse <code>pLineBiDi</code> before <code>pParaBiDi</code>.
|
|
* In other words, you must destroy or reuse the <code>UBiDi</code> object for a line
|
|
* before the object for its parent paragraph.<p>
|
|
*
|
|
* The text pointer that was stored in <code>pParaBiDi</code> is also copied,
|
|
* and <code>start</code> is added to it so that it points to the beginning of the
|
|
* line for this object.
|
|
*
|
|
* @param pParaBiDi is the parent paragraph object.
|
|
*
|
|
* @param start is the line's first index into the paragraph text.
|
|
*
|
|
* @param limit is just behind the line's last index into the paragraph text
|
|
* (its last index +1).<br>
|
|
* It must be <code>0<=start<=limit<=</code>paragraph length.
|
|
*
|
|
* @param pLineBiDi is the object that will now represent a line of the paragraph.
|
|
*
|
|
* @param pErrorCode must be a valid pointer to an error code value,
|
|
* which must not indicate a failure before the function call.
|
|
*
|
|
* @see ubidi_setPara
|
|
* @stable ICU 2.0
|
|
*/
|
|
U_STABLE void U_EXPORT2
|
|
ubidi_setLine(const UBiDi *pParaBiDi,
|
|
int32_t start, int32_t limit,
|
|
UBiDi *pLineBiDi,
|
|
UErrorCode *pErrorCode);
|
|
|
|
/**
|
|
* Get the directionality of the text.
|
|
*
|
|
* @param pBiDi is the paragraph or line <code>UBiDi</code> object.
|
|
*
|
|
* @return A <code>UBIDI_XXX</code> value that indicates if the entire text
|
|
* represented by this object is unidirectional,
|
|
* and which direction, or if it is mixed-directional.
|
|
*
|
|
* @see UBiDiDirection
|
|
* @stable ICU 2.0
|
|
*/
|
|
U_STABLE UBiDiDirection U_EXPORT2
|
|
ubidi_getDirection(const UBiDi *pBiDi);
|
|
|
|
/**
|
|
* Get the pointer to the text.
|
|
*
|
|
* @param pBiDi is the paragraph or line <code>UBiDi</code> object.
|
|
*
|
|
* @return The pointer to the text that the UBiDi object was created for.
|
|
*
|
|
* @see ubidi_setPara
|
|
* @see ubidi_setLine
|
|
* @stable ICU 2.0
|
|
*/
|
|
U_STABLE const UChar * U_EXPORT2
|
|
ubidi_getText(const UBiDi *pBiDi);
|
|
|
|
/**
|
|
* Get the length of the text.
|
|
*
|
|
* @param pBiDi is the paragraph or line <code>UBiDi</code> object.
|
|
*
|
|
* @return The length of the text that the UBiDi object was created for.
|
|
* @stable ICU 2.0
|
|
*/
|
|
U_STABLE int32_t U_EXPORT2
|
|
ubidi_getLength(const UBiDi *pBiDi);
|
|
|
|
/**
|
|
* Get the paragraph level of the text.
|
|
*
|
|
* @param pBiDi is the paragraph or line <code>UBiDi</code> object.
|
|
*
|
|
* @return The paragraph level.
|
|
*
|
|
* @see UBiDiLevel
|
|
* @stable ICU 2.0
|
|
*/
|
|
U_STABLE UBiDiLevel U_EXPORT2
|
|
ubidi_getParaLevel(const UBiDi *pBiDi);
|
|
|
|
/**
|
|
* Get the level for one character.
|
|
*
|
|
* @param pBiDi is the paragraph or line <code>UBiDi</code> object.
|
|
*
|
|
* @param charIndex the index of a character.
|
|
*
|
|
* @return The level for the character at charIndex.
|
|
*
|
|
* @see UBiDiLevel
|
|
* @stable ICU 2.0
|
|
*/
|
|
U_STABLE UBiDiLevel U_EXPORT2
|
|
ubidi_getLevelAt(const UBiDi *pBiDi, int32_t charIndex);
|
|
|
|
/**
|
|
* Get an array of levels for each character.<p>
|
|
*
|
|
* Note that this function may allocate memory under some
|
|
* circumstances, unlike <code>ubidi_getLevelAt()</code>.
|
|
*
|
|
* @param pBiDi is the paragraph or line <code>UBiDi</code> object.
|
|
*
|
|
* @param pErrorCode must be a valid pointer to an error code value,
|
|
* which must not indicate a failure before the function call.
|
|
*
|
|
* @return The levels array for the text,
|
|
* or <code>NULL</code> if an error occurs.
|
|
*
|
|
* @see UBiDiLevel
|
|
* @stable ICU 2.0
|
|
*/
|
|
U_STABLE const UBiDiLevel * U_EXPORT2
|
|
ubidi_getLevels(UBiDi *pBiDi, UErrorCode *pErrorCode);
|
|
|
|
/**
|
|
* Get a logical run.
|
|
* This function returns information about a run and is used
|
|
* to retrieve runs in logical order.<p>
|
|
* This is especially useful for line-breaking on a paragraph.
|
|
*
|
|
* @param pBiDi is the paragraph or line <code>UBiDi</code> object.
|
|
*
|
|
* @param logicalStart is the first character of the run.
|
|
*
|
|
* @param pLogicalLimit will receive the limit of the run.
|
|
* The l-value that you point to here may be the
|
|
* same expression (variable) as the one for
|
|
* <code>logicalStart</code>.
|
|
* This pointer can be <code>NULL</code> if this
|
|
* value is not necessary.
|
|
*
|
|
* @param pLevel will receive the level of the run.
|
|
* This pointer can be <code>NULL</code> if this
|
|
* value is not necessary.
|
|
* @stable ICU 2.0
|
|
*/
|
|
U_STABLE void U_EXPORT2
|
|
ubidi_getLogicalRun(const UBiDi *pBiDi, int32_t logicalStart,
|
|
int32_t *pLogicalLimit, UBiDiLevel *pLevel);
|
|
|
|
/**
|
|
* Get the number of runs.
|
|
* This function may invoke the actual reordering on the
|
|
* <code>UBiDi</code> object, after <code>ubidi_setPara()</code>
|
|
* may have resolved only the levels of the text. Therefore,
|
|
* <code>ubidi_countRuns()</code> may have to allocate memory,
|
|
* and may fail doing so.
|
|
*
|
|
* @param pBiDi is the paragraph or line <code>UBiDi</code> object.
|
|
*
|
|
* @param pErrorCode must be a valid pointer to an error code value,
|
|
* which must not indicate a failure before the function call.
|
|
*
|
|
* @return The number of runs.
|
|
* @stable ICU 2.0
|
|
*/
|
|
U_STABLE int32_t U_EXPORT2
|
|
ubidi_countRuns(UBiDi *pBiDi, UErrorCode *pErrorCode);
|
|
|
|
/**
|
|
* Get one run's logical start, length, and directionality,
|
|
* which can be 0 for LTR or 1 for RTL.
|
|
* In an RTL run, the character at the logical start is
|
|
* visually on the right of the displayed run.
|
|
* The length is the number of characters in the run.<p>
|
|
* <code>ubidi_countRuns()</code> should be called
|
|
* before the runs are retrieved.
|
|
*
|
|
* @param pBiDi is the paragraph or line <code>UBiDi</code> object.
|
|
*
|
|
* @param runIndex is the number of the run in visual order, in the
|
|
* range <code>[0..ubidi_countRuns(pBiDi)-1]</code>.
|
|
*
|
|
* @param pLogicalStart is the first logical character index in the text.
|
|
* The pointer may be <code>NULL</code> if this index is not needed.
|
|
*
|
|
* @param pLength is the number of characters (at least one) in the run.
|
|
* The pointer may be <code>NULL</code> if this is not needed.
|
|
*
|
|
* @return the directionality of the run,
|
|
* <code>UBIDI_LTR==0</code> or <code>UBIDI_RTL==1</code>,
|
|
* never <code>UBIDI_MIXED</code>.
|
|
*
|
|
* @see ubidi_countRuns
|
|
*
|
|
* Example:
|
|
* <pre>
|
|
* \code
|
|
* int32_t i, count=ubidi_countRuns(pBiDi),
|
|
* logicalStart, visualIndex=0, length;
|
|
* for(i=0; i<count; ++i) {
|
|
* if(UBIDI_LTR==ubidi_getVisualRun(pBiDi, i, &logicalStart, &length)) {
|
|
* do { // LTR
|
|
* show_char(text[logicalStart++], visualIndex++);
|
|
* } while(--length>0);
|
|
* } else {
|
|
* logicalStart+=length; // logicalLimit
|
|
* do { // RTL
|
|
* show_char(text[--logicalStart], visualIndex++);
|
|
* } while(--length>0);
|
|
* }
|
|
* }
|
|
*\endcode
|
|
* </pre>
|
|
*
|
|
* Note that in right-to-left runs, code like this places
|
|
* modifier letters before base characters and second surrogates
|
|
* before first ones.
|
|
* @stable ICU 2.0
|
|
*/
|
|
U_STABLE UBiDiDirection U_EXPORT2
|
|
ubidi_getVisualRun(UBiDi *pBiDi, int32_t runIndex,
|
|
int32_t *pLogicalStart, int32_t *pLength);
|
|
|
|
/**
|
|
* Get the visual position from a logical text position.
|
|
* If such a mapping is used many times on the same
|
|
* <code>UBiDi</code> object, then calling
|
|
* <code>ubidi_getLogicalMap()</code> is more efficient.<p>
|
|
*
|
|
* Note that in right-to-left runs, this mapping places
|
|
* modifier letters before base characters and second surrogates
|
|
* before first ones.
|
|
*
|
|
* @param pBiDi is the paragraph or line <code>UBiDi</code> object.
|
|
*
|
|
* @param logicalIndex is the index of a character in the text.
|
|
*
|
|
* @param pErrorCode must be a valid pointer to an error code value,
|
|
* which must not indicate a failure before the function call.
|
|
*
|
|
* @return The visual position of this character.
|
|
*
|
|
* @see ubidi_getLogicalMap
|
|
* @see ubidi_getLogicalIndex
|
|
* @stable ICU 2.0
|
|
*/
|
|
U_STABLE int32_t U_EXPORT2
|
|
ubidi_getVisualIndex(UBiDi *pBiDi, int32_t logicalIndex, UErrorCode *pErrorCode);
|
|
|
|
/**
|
|
* Get the logical text position from a visual position.
|
|
* If such a mapping is used many times on the same
|
|
* <code>UBiDi</code> object, then calling
|
|
* <code>ubidi_getVisualMap()</code> is more efficient.<p>
|
|
*
|
|
* This is the inverse function to <code>ubidi_getVisualIndex()</code>.
|
|
*
|
|
* @param pBiDi is the paragraph or line <code>UBiDi</code> object.
|
|
*
|
|
* @param visualIndex is the visual position of a character.
|
|
*
|
|
* @param pErrorCode must be a valid pointer to an error code value,
|
|
* which must not indicate a failure before the function call.
|
|
*
|
|
* @return The index of this character in the text.
|
|
*
|
|
* @see ubidi_getVisualMap
|
|
* @see ubidi_getVisualIndex
|
|
* @stable ICU 2.0
|
|
*/
|
|
U_STABLE int32_t U_EXPORT2
|
|
ubidi_getLogicalIndex(UBiDi *pBiDi, int32_t visualIndex, UErrorCode *pErrorCode);
|
|
|
|
/**
|
|
* Get a logical-to-visual index map (array) for the characters in the UBiDi
|
|
* (paragraph or line) object.
|
|
*
|
|
* @param pBiDi is the paragraph or line <code>UBiDi</code> object.
|
|
*
|
|
* @param indexMap is a pointer to an array of <code>ubidi_getLength()</code>
|
|
* indexes which will reflect the reordering of the characters.
|
|
* The array does not need to be initialized.<p>
|
|
* The index map will result in <code>indexMap[logicalIndex]==visualIndex</code>.<p>
|
|
*
|
|
* @param pErrorCode must be a valid pointer to an error code value,
|
|
* which must not indicate a failure before the function call.
|
|
*
|
|
* @see ubidi_getVisualMap
|
|
* @see ubidi_getVisualIndex
|
|
* @stable ICU 2.0
|
|
*/
|
|
U_STABLE void U_EXPORT2
|
|
ubidi_getLogicalMap(UBiDi *pBiDi, int32_t *indexMap, UErrorCode *pErrorCode);
|
|
|
|
/**
|
|
* Get a visual-to-logical index map (array) for the characters in the UBiDi
|
|
* (paragraph or line) object.
|
|
*
|
|
* @param pBiDi is the paragraph or line <code>UBiDi</code> object.
|
|
*
|
|
* @param indexMap is a pointer to an array of <code>ubidi_getLength()</code>
|
|
* indexes which will reflect the reordering of the characters.
|
|
* The array does not need to be initialized.<p>
|
|
* The index map will result in <code>indexMap[visualIndex]==logicalIndex</code>.<p>
|
|
*
|
|
* @param pErrorCode must be a valid pointer to an error code value,
|
|
* which must not indicate a failure before the function call.
|
|
*
|
|
* @see ubidi_getLogicalMap
|
|
* @see ubidi_getLogicalIndex
|
|
* @stable ICU 2.0
|
|
*/
|
|
U_STABLE void U_EXPORT2
|
|
ubidi_getVisualMap(UBiDi *pBiDi, int32_t *indexMap, UErrorCode *pErrorCode);
|
|
|
|
/**
|
|
* This is a convenience function that does not use a UBiDi object.
|
|
* It is intended to be used for when an application has determined the levels
|
|
* of objects (character sequences) and just needs to have them reordered (L2).
|
|
* This is equivalent to using <code>ubidi_getLogicalMap</code> on a
|
|
* <code>UBiDi</code> object.
|
|
*
|
|
* @param levels is an array with <code>length</code> levels that have been determined by
|
|
* the application.
|
|
*
|
|
* @param length is the number of levels in the array, or, semantically,
|
|
* the number of objects to be reordered.
|
|
* It must be <code>length>0</code>.
|
|
*
|
|
* @param indexMap is a pointer to an array of <code>length</code>
|
|
* indexes which will reflect the reordering of the characters.
|
|
* The array does not need to be initialized.<p>
|
|
* The index map will result in <code>indexMap[logicalIndex]==visualIndex</code>.
|
|
* @stable ICU 2.0
|
|
*/
|
|
U_STABLE void U_EXPORT2
|
|
ubidi_reorderLogical(const UBiDiLevel *levels, int32_t length, int32_t *indexMap);
|
|
|
|
/**
|
|
* This is a convenience function that does not use a UBiDi object.
|
|
* It is intended to be used for when an application has determined the levels
|
|
* of objects (character sequences) and just needs to have them reordered (L2).
|
|
* This is equivalent to using <code>ubidi_getVisualMap</code> on a
|
|
* <code>UBiDi</code> object.
|
|
*
|
|
* @param levels is an array with <code>length</code> levels that have been determined by
|
|
* the application.
|
|
*
|
|
* @param length is the number of levels in the array, or, semantically,
|
|
* the number of objects to be reordered.
|
|
* It must be <code>length>0</code>.
|
|
*
|
|
* @param indexMap is a pointer to an array of <code>length</code>
|
|
* indexes which will reflect the reordering of the characters.
|
|
* The array does not need to be initialized.<p>
|
|
* The index map will result in <code>indexMap[visualIndex]==logicalIndex</code>.
|
|
* @stable ICU 2.0
|
|
*/
|
|
U_STABLE void U_EXPORT2
|
|
ubidi_reorderVisual(const UBiDiLevel *levels, int32_t length, int32_t *indexMap);
|
|
|
|
/**
|
|
* Invert an index map.
|
|
* The one-to-one index mapping of the first map is inverted and written to
|
|
* the second one.
|
|
*
|
|
* @param srcMap is an array with <code>length</code> indexes
|
|
* which define the original mapping.
|
|
*
|
|
* @param destMap is an array with <code>length</code> indexes
|
|
* which will be filled with the inverse mapping.
|
|
*
|
|
* @param length is the length of each array.
|
|
* @stable ICU 2.0
|
|
*/
|
|
U_STABLE void U_EXPORT2
|
|
ubidi_invertMap(const int32_t *srcMap, int32_t *destMap, int32_t length);
|
|
|
|
/** option flags for ubidi_writeReordered() */
|
|
|
|
/**
|
|
* option bit for ubidi_writeReordered():
|
|
* keep combining characters after their base characters in RTL runs
|
|
*
|
|
* @see ubidi_writeReordered
|
|
* @stable ICU 2.0
|
|
*/
|
|
#define UBIDI_KEEP_BASE_COMBINING 1
|
|
|
|
/**
|
|
* option bit for ubidi_writeReordered():
|
|
* replace characters with the "mirrored" property in RTL runs
|
|
* by their mirror-image mappings
|
|
*
|
|
* @see ubidi_writeReordered
|
|
* @stable ICU 2.0
|
|
*/
|
|
#define UBIDI_DO_MIRRORING 2
|
|
|
|
/**
|
|
* option bit for ubidi_writeReordered():
|
|
* surround the run with LRMs if necessary;
|
|
* this is part of the approximate "inverse BiDi" algorithm
|
|
*
|
|
* @see ubidi_setInverse
|
|
* @see ubidi_writeReordered
|
|
* @stable ICU 2.0
|
|
*/
|
|
#define UBIDI_INSERT_LRM_FOR_NUMERIC 4
|
|
|
|
/**
|
|
* option bit for ubidi_writeReordered():
|
|
* remove BiDi control characters
|
|
* (this does not affect UBIDI_INSERT_LRM_FOR_NUMERIC)
|
|
*
|
|
* @see ubidi_writeReordered
|
|
* @stable ICU 2.0
|
|
*/
|
|
#define UBIDI_REMOVE_BIDI_CONTROLS 8
|
|
|
|
/**
|
|
* option bit for ubidi_writeReordered():
|
|
* write the output in reverse order
|
|
*
|
|
* <p>This has the same effect as calling <code>ubidi_writeReordered()</code>
|
|
* first without this option, and then calling
|
|
* <code>ubidi_writeReverse()</code> without mirroring.
|
|
* Doing this in the same step is faster and avoids a temporary buffer.
|
|
* An example for using this option is output to a character terminal that
|
|
* is designed for RTL scripts and stores text in reverse order.</p>
|
|
*
|
|
* @see ubidi_writeReordered
|
|
* @stable ICU 2.0
|
|
*/
|
|
#define UBIDI_OUTPUT_REVERSE 16
|
|
|
|
/**
|
|
* Take a <code>UBiDi</code> object containing the reordering
|
|
* information for one paragraph or line of text as set by
|
|
* <code>ubidi_setPara()</code> or <code>ubidi_setLine()</code> and
|
|
* write a reordered string to the destination buffer.
|
|
*
|
|
* This function preserves the integrity of characters with multiple
|
|
* code units and (optionally) modifier letters.
|
|
* Characters in RTL runs can be replaced by mirror-image characters
|
|
* in the destination buffer. Note that "real" mirroring has
|
|
* to be done in a rendering engine by glyph selection
|
|
* and that for many "mirrored" characters there are no
|
|
* Unicode characters as mirror-image equivalents.
|
|
* There are also options to insert or remove BiDi control
|
|
* characters; see the description of the <code>destSize</code>
|
|
* and <code>options</code> parameters and of the option bit flags.
|
|
*
|
|
* @see UBIDI_DO_MIRRORING
|
|
* @see UBIDI_INSERT_LRM_FOR_NUMERIC
|
|
* @see UBIDI_KEEP_BASE_COMBINING
|
|
* @see UBIDI_OUTPUT_REVERSE
|
|
* @see UBIDI_REMOVE_BIDI_CONTROLS
|
|
*
|
|
* @param pBiDi A pointer to a <code>UBiDi</code> object that
|
|
* is set by <code>ubidi_setPara()</code> or
|
|
* <code>ubidi_setLine()</code> and contains the reordering
|
|
* information for the text that it was defined for,
|
|
* as well as a pointer to that text.
|
|
* <p>The text was aliased (only the pointer was stored
|
|
* without copying the contents) and must not have been modified
|
|
* since the <code>ubidi_setPara()</code> call.</p>
|
|
*
|
|
* @param dest A pointer to where the reordered text is to be copied.
|
|
* The source text and <code>dest[destSize]</code>
|
|
* must not overlap.
|
|
*
|
|
* @param destSize The size of the <code>dest</code> buffer,
|
|
* in number of UChars.
|
|
* If the <code>UBIDI_INSERT_LRM_FOR_NUMERIC</code>
|
|
* option is set, then the destination length could be
|
|
* as large as
|
|
* <code>ubidi_getLength(pBiDi)+2*ubidi_countRuns(pBiDi)</code>.
|
|
* If the <code>UBIDI_REMOVE_BIDI_CONTROLS</code> option
|
|
* is set, then the destination length may be less than
|
|
* <code>ubidi_getLength(pBiDi)</code>.
|
|
* If none of these options is set, then the destination length
|
|
* will be exactly <code>ubidi_getLength(pBiDi)</code>.
|
|
*
|
|
* @param options A bit set of options for the reordering that control
|
|
* how the reordered text is written.
|
|
* The options include mirroring the characters on a code
|
|
* point basis and inserting LRM characters, which is used
|
|
* especially for transforming visually stored text
|
|
* to logically stored text (although this is still an
|
|
* imperfect implementation of an "inverse BiDi" algorithm
|
|
* because it uses the "forward BiDi" algorithm at its core).
|
|
* The available options are:
|
|
* <code>#UBIDI_DO_MIRRORING</code>,
|
|
* <code>#UBIDI_INSERT_LRM_FOR_NUMERIC</code>,
|
|
* <code>#UBIDI_KEEP_BASE_COMBINING</code>,
|
|
* <code>#UBIDI_OUTPUT_REVERSE</code>,
|
|
* <code>#UBIDI_REMOVE_BIDI_CONTROLS</code>
|
|
*
|
|
* @param pErrorCode must be a valid pointer to an error code value,
|
|
* which must not indicate a failure before the function call.
|
|
*
|
|
* @return The length of the output string.
|
|
* @stable ICU 2.0
|
|
*/
|
|
U_STABLE int32_t U_EXPORT2
|
|
ubidi_writeReordered(UBiDi *pBiDi,
|
|
UChar *dest, int32_t destSize,
|
|
uint16_t options,
|
|
UErrorCode *pErrorCode);
|
|
|
|
/**
|
|
* Reverse a Right-To-Left run of Unicode text.
|
|
*
|
|
* This function preserves the integrity of characters with multiple
|
|
* code units and (optionally) modifier letters.
|
|
* Characters can be replaced by mirror-image characters
|
|
* in the destination buffer. Note that "real" mirroring has
|
|
* to be done in a rendering engine by glyph selection
|
|
* and that for many "mirrored" characters there are no
|
|
* Unicode characters as mirror-image equivalents.
|
|
* There are also options to insert or remove BiDi control
|
|
* characters.
|
|
*
|
|
* This function is the implementation for reversing RTL runs as part
|
|
* of <code>ubidi_writeReordered()</code>. For detailed descriptions
|
|
* of the parameters, see there.
|
|
* Since no BiDi controls are inserted here, the output string length
|
|
* will never exceed <code>srcLength</code>.
|
|
*
|
|
* @see ubidi_writeReordered
|
|
*
|
|
* @param src A pointer to the RTL run text.
|
|
*
|
|
* @param srcLength The length of the RTL run.
|
|
*
|
|
* @param dest A pointer to where the reordered text is to be copied.
|
|
* <code>src[srcLength]</code> and <code>dest[destSize]</code>
|
|
* must not overlap.
|
|
*
|
|
* @param destSize The size of the <code>dest</code> buffer,
|
|
* in number of UChars.
|
|
* If the <code>UBIDI_REMOVE_BIDI_CONTROLS</code> option
|
|
* is set, then the destination length may be less than
|
|
* <code>srcLength</code>.
|
|
* If this option is not set, then the destination length
|
|
* will be exactly <code>srcLength</code>.
|
|
*
|
|
* @param options A bit set of options for the reordering that control
|
|
* how the reordered text is written.
|
|
* See the <code>options</code> parameter in <code>ubidi_writeReordered()</code>.
|
|
*
|
|
* @param pErrorCode must be a valid pointer to an error code value,
|
|
* which must not indicate a failure before the function call.
|
|
*
|
|
* @return The length of the output string.
|
|
* @stable ICU 2.0
|
|
*/
|
|
U_STABLE int32_t U_EXPORT2
|
|
ubidi_writeReverse(const UChar *src, int32_t srcLength,
|
|
UChar *dest, int32_t destSize,
|
|
uint16_t options,
|
|
UErrorCode *pErrorCode);
|
|
|
|
/*#define BIDI_SAMPLE_CODE*/
|
|
/*@}*/
|
|
|
|
#endif
|