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******************************************************************************
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* Copyright (C) 1999-2010, International Business Machines
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* Corporation and others. All Rights Reserved.
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******************************************************************************
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* tab size: 8 (not used)
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* created on: 1999jul27
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* created by: Markus W. Scherer, updated by Matitiahu Allouche
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#include "unicode/utypes.h"
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#include "unicode/uchar.h"
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#include "unicode/localpointer.h"
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* \brief C API: Bidi algorithm
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* <h2>Bidi algorithm for ICU</h2>
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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>.<p>
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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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* <h3>General remarks about the API:</h3>
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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
44
* 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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* The "limit" of a sequence of characters is the position just after their
48
* last character, i.e., one more than that position.<p>
50
* 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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* @author Markus W. Scherer
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* <h4> Sample code for the ICU Bidi API </h4>
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* <h5>Rendering a paragraph with the ICU Bidi API</h5>
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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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* <p>The basic assumptions are:</p>
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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>
75
* <li>The line-breaking algorithm is very complicated
76
* and Locale-dependent -
77
* and therefore its implementation omitted from this sample code.</li>
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*#include "unicode/ubidi.h"
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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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*typedef struct { int32_t limit; Style style; } StyleRun;
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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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* // 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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* const StyleRun *styleRuns, int styleRunStart, int *pStyleRunLimit,
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* // render runs on a line sequentially, always from left to right
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* // prepare rendering a new line
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* void startLine(UBiDiDirection textDirection, int lineWidth);
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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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* // 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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* // 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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* // iterate over style runs
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* if(direction==UBIDI_LTR) {
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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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* for(i=styleRunCount-1; i>=0; --i) {
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* styleStart=styleRun[i-1].limit;
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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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* // 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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* if(styleRunCount<=1) {
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* renderRun(text, start, limit, direction, styleRuns[0].style);
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* renderDirectionalRun(text, start, limit,
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* direction, styleRuns, styleRunCount);
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* // mixed-directional
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* int32_t count, i, length;
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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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* // 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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* // 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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*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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* UErrorCode *pErrorCode) {
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* if(pErrorCode==NULL || U_FAILURE(*pErrorCode) || length<=0) {
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* para=ubidi_openSized(length, 0, pErrorCode);
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* if(para==NULL) { return; }
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* ubidi_setPara(para, text, length,
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* textDirection ? UBIDI_DEFAULT_RTL : UBIDI_DEFAULT_LTR,
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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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* if(styleRuns==NULL || styleRunCount<=0) {
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* styleRuns=&styleRun;
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* // assume styleRuns[styleRunCount-1].limit>=length
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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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* // prepare rendering a new line from either left or right
239
* startLine(paraLevel, width);
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* renderLine(para, text, 0, length,
242
* styleRuns, styleRunCount);
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* // we need to render several lines
247
* line=ubidi_openSized(length, 0, pErrorCode);
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* int32_t start=0, limit;
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* int styleRunStart=0, styleRunLimit;
254
* styleRunLimit=styleRunCount;
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* getLineBreak(text, start, &limit, para,
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* styleRuns, styleRunStart, &styleRunLimit,
258
* ubidi_setLine(para, start, limit, line, pErrorCode);
259
* if(U_SUCCESS(*pErrorCode)) {
260
* // prepare rendering a new line
261
* // from either left or right
262
* startLine(paraLevel, width);
264
* renderLine(line, text, start, limit,
265
* styleRuns+styleRunStart,
266
* styleRunLimit-styleRunStart);
268
* if(limit==length) { break; }
270
* styleRunStart=styleRunLimit-1;
271
* if(start>=styleRuns[styleRunStart].limit) {
291
* UBiDiLevel is the type of the level values in this
292
* Bidi implementation.
293
* It holds an embedding level and indicates the visual direction
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* by its bit 0 (even/odd value).<p>
296
* It can also hold non-level values for the
297
* <code>paraLevel</code> and <code>embeddingLevels</code>
298
* arguments of <code>ubidi_setPara()</code>; there:
300
* <li>bit 7 of an <code>embeddingLevels[]</code>
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* value indicates whether the using application is
302
* specifying the level of a character to <i>override</i> whatever the
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* Bidi implementation would resolve it to.</li>
304
* <li><code>paraLevel</code> can be set to the
305
* pseudo-level values <code>UBIDI_DEFAULT_LTR</code>
306
* and <code>UBIDI_DEFAULT_RTL</code>.</li>
311
* <p>The related constants are not real, valid level values.
312
* <code>UBIDI_DEFAULT_XXX</code> can be used to specify
313
* a default for the paragraph level for
314
* when the <code>ubidi_setPara()</code> function
315
* shall determine it but there is no
316
* strongly typed character in the input.<p>
318
* 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,
320
* just like with normal LTR and RTL level values -
321
* these special values are designed that way. Also, the implementation
322
* assumes that UBIDI_MAX_EXPLICIT_LEVEL is odd.
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* @see UBIDI_DEFAULT_LTR
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* @see UBIDI_DEFAULT_RTL
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* @see UBIDI_LEVEL_OVERRIDE
327
* @see UBIDI_MAX_EXPLICIT_LEVEL
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typedef uint8_t UBiDiLevel;
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/** Paragraph level setting.<p>
334
* Constant indicating that the base direction depends on the first strong
335
* directional character in the text according to the Unicode Bidirectional
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* Algorithm. If no strong directional character is present,
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* then set the paragraph level to 0 (left-to-right).<p>
339
* If this value is used in conjunction with reordering modes
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* <code>UBIDI_REORDER_INVERSE_LIKE_DIRECT</code> or
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* <code>UBIDI_REORDER_INVERSE_FOR_NUMBERS_SPECIAL</code>, the text to reorder
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* is assumed to be visual LTR, and the text after reordering is required
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* to be the corresponding logical string with appropriate contextual
344
* direction. The direction of the result string will be RTL if either
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* the righmost or leftmost strong character of the source text is RTL
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* or Arabic Letter, the direction will be LTR otherwise.<p>
348
* If reordering option <code>UBIDI_OPTION_INSERT_MARKS</code> is set, an RLM may
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* be added at the beginning of the result string to ensure round trip
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* (that the result string, when reordered back to visual, will produce
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* the original source text).
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* @see UBIDI_REORDER_INVERSE_LIKE_DIRECT
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* @see UBIDI_REORDER_INVERSE_FOR_NUMBERS_SPECIAL
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#define UBIDI_DEFAULT_LTR 0xfe
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/** Paragraph level setting.<p>
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* Constant indicating that the base direction depends on the first strong
361
* directional character in the text according to the Unicode Bidirectional
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* Algorithm. If no strong directional character is present,
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* then set the paragraph level to 1 (right-to-left).<p>
365
* If this value is used in conjunction with reordering modes
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* <code>UBIDI_REORDER_INVERSE_LIKE_DIRECT</code> or
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* <code>UBIDI_REORDER_INVERSE_FOR_NUMBERS_SPECIAL</code>, the text to reorder
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* is assumed to be visual LTR, and the text after reordering is required
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* to be the corresponding logical string with appropriate contextual
370
* direction. The direction of the result string will be RTL if either
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* the righmost or leftmost strong character of the source text is RTL
372
* or Arabic Letter, or if the text contains no strong character;
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* the direction will be LTR otherwise.<p>
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* If reordering option <code>UBIDI_OPTION_INSERT_MARKS</code> is set, an RLM may
376
* be added at the beginning of the result string to ensure round trip
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* (that the result string, when reordered back to visual, will produce
378
* the original source text).
379
* @see UBIDI_REORDER_INVERSE_LIKE_DIRECT
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* @see UBIDI_REORDER_INVERSE_FOR_NUMBERS_SPECIAL
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#define UBIDI_DEFAULT_RTL 0xff
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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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#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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#define UBIDI_LEVEL_OVERRIDE 0x80
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* Special value which can be returned by the mapping functions when a logical
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* index has no corresponding visual index or vice-versa. This may happen
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* for the logical-to-visual mapping of a Bidi control when option
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* <code>#UBIDI_OPTION_REMOVE_CONTROLS</code> is specified. This can also happen
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* for the visual-to-logical mapping of a Bidi mark (LRM or RLM) inserted
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* by option <code>#UBIDI_OPTION_INSERT_MARKS</code>.
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* @see ubidi_getVisualIndex
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* @see ubidi_getVisualMap
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* @see ubidi_getLogicalIndex
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* @see ubidi_getLogicalMap
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#define UBIDI_MAP_NOWHERE (-1)
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* <code>UBiDiDirection</code> values indicate the text direction.
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enum UBiDiDirection {
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/** Left-to-right text. This is a 0 value.
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* <li>As return value for <code>ubidi_getDirection()</code>, it means
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* that the source string contains no right-to-left characters, or
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* that the source string is empty and the paragraph level is even.
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* <li> As return value for <code>ubidi_getBaseDirection()</code>, it
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* means that the first strong character of the source string has
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* a left-to-right direction.
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/** Right-to-left text. This is a 1 value.
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* <li>As return value for <code>ubidi_getDirection()</code>, it means
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* that the source string contains no left-to-right characters, or
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* that the source string is empty and the paragraph level is odd.
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* <li> As return value for <code>ubidi_getBaseDirection()</code>, it
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* means that the first strong character of the source string has
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* a right-to-left direction.
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/** Mixed-directional text.
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* <p>As return value for <code>ubidi_getDirection()</code>, it means
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* that the source string contains both left-to-right and
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* right-to-left characters.
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/** No strongly directional text.
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* <p>As return value for <code>ubidi_getBaseDirection()</code>, it means
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* that the source string is missing or empty, or contains neither left-to-right
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* nor right-to-left characters.
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/** @stable ICU 2.0 */
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typedef enum UBiDiDirection UBiDiDirection;
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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 (or multiple paragraphs)
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* of text 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 one or more paragraphs which are
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* then interpreted each as one single line.
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/** @stable ICU 2.0 */
474
typedef struct UBiDi UBiDi;
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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 piece of text containing one or more paragraphs
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* by <code>ubidi_setPara()</code>
481
* or the Bidi properties of a line within a paragraph by
482
* <code>ubidi_setLine()</code>.<p>
483
* This object can be reused for as long as it is not deallocated
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* by calling <code>ubidi_close()</code>.<p>
485
* <code>ubidi_setPara()</code> and <code>ubidi_setLine()</code> will allocate
486
* additional memory for internal structures as necessary.
488
* @return An empty <code>UBiDi</code> object.
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U_STABLE UBiDi * U_EXPORT2
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* Allocate a <code>UBiDi</code> structure with preallocated memory
496
* for internal structures.
497
* This function provides a <code>UBiDi</code> object like <code>ubidi_open()</code>
498
* with no arguments, but it also preallocates memory for internal structures
499
* according to the sizings supplied by the caller.<p>
500
* Subsequent functions will not allocate any more memory, and are thus
501
* guaranteed not to fail because of lack of memory.<p>
502
* The preallocation can be limited to some of the internal memory
503
* by setting some values to 0 here. That means that if, e.g.,
504
* <code>maxRunCount</code> cannot be reasonably predetermined and should not
505
* be set to <code>maxLength</code> (the only failproof value) to avoid
506
* wasting memory, then <code>maxRunCount</code> could be set to 0 here
507
* and the internal structures that are associated with it will be allocated
508
* on demand, just like with <code>ubidi_open()</code>.
510
* @param maxLength is the maximum text or line length that internal memory
511
* will be preallocated for. An attempt to associate this object with a
512
* longer text will fail, unless this value is 0, which leaves the allocation
513
* up to the implementation.
515
* @param maxRunCount is the maximum anticipated number of same-level runs
516
* that internal memory will be preallocated for. An attempt to access
517
* visual runs on an object that was not preallocated for as many runs
518
* as the text was actually resolved to will fail,
519
* unless this value is 0, which leaves the allocation up to the implementation.<br><br>
520
* The number of runs depends on the actual text and maybe anywhere between
521
* 1 and <code>maxLength</code>. It is typically small.
523
* @param pErrorCode must be a valid pointer to an error code value.
525
* @return An empty <code>UBiDi</code> object with preallocated memory.
528
U_STABLE UBiDi * U_EXPORT2
529
ubidi_openSized(int32_t maxLength, int32_t maxRunCount, UErrorCode *pErrorCode);
532
* <code>ubidi_close()</code> must be called to free the memory
533
* associated with a UBiDi object.<p>
535
* <strong>Important: </strong>
536
* A parent <code>UBiDi</code> object must not be destroyed or reused if
537
* it still has children.
538
* If a <code>UBiDi</code> object has become the <i>child</i>
539
* of another one (its <i>parent</i>) by calling
540
* <code>ubidi_setLine()</code>, then the child object must
541
* be destroyed (closed) or reused (by calling
542
* <code>ubidi_setPara()</code> or <code>ubidi_setLine()</code>)
543
* before the parent object.
545
* @param pBiDi is a <code>UBiDi</code> object.
551
U_STABLE void U_EXPORT2
552
ubidi_close(UBiDi *pBiDi);
554
#if U_SHOW_CPLUSPLUS_API
559
* \class LocalUBiDiPointer
560
* "Smart pointer" class, closes a UBiDi via ubidi_close().
561
* For most methods see the LocalPointerBase base class.
563
* @see LocalPointerBase
567
U_DEFINE_LOCAL_OPEN_POINTER(LocalUBiDiPointer, UBiDi, ubidi_close);
574
* Modify the operation of the Bidi algorithm such that it
575
* approximates an "inverse Bidi" algorithm. This function
576
* must be called before <code>ubidi_setPara()</code>.
578
* <p>The normal operation of the Bidi algorithm as described
579
* in the Unicode Technical Report is to take text stored in logical
580
* (keyboard, typing) order and to determine the reordering of it for visual
582
* Some legacy systems store text in visual order, and for operations
583
* with standard, Unicode-based algorithms, the text needs to be transformed
584
* to logical order. This is effectively the inverse algorithm of the
585
* described Bidi algorithm. Note that there is no standard algorithm for
586
* this "inverse Bidi" and that the current implementation provides only an
587
* approximation of "inverse Bidi".</p>
589
* <p>With <code>isInverse</code> set to <code>TRUE</code>,
590
* this function changes the behavior of some of the subsequent functions
591
* in a way that they can be used for the inverse Bidi algorithm.
592
* Specifically, runs of text with numeric characters will be treated in a
593
* special way and may need to be surrounded with LRM characters when they are
594
* written in reordered sequence.</p>
596
* <p>Output runs should be retrieved using <code>ubidi_getVisualRun()</code>.
597
* Since the actual input for "inverse Bidi" is visually ordered text and
598
* <code>ubidi_getVisualRun()</code> gets the reordered runs, these are actually
599
* the runs of the logically ordered output.</p>
601
* <p>Calling this function with argument <code>isInverse</code> set to
602
* <code>TRUE</code> is equivalent to calling
603
* <code>ubidi_setReorderingMode</code> with argument
604
* <code>reorderingMode</code>
605
* set to <code>#UBIDI_REORDER_INVERSE_NUMBERS_AS_L</code>.<br>
606
* Calling this function with argument <code>isInverse</code> set to
607
* <code>FALSE</code> is equivalent to calling
608
* <code>ubidi_setReorderingMode</code> with argument
609
* <code>reorderingMode</code>
610
* set to <code>#UBIDI_REORDER_DEFAULT</code>.
612
* @param pBiDi is a <code>UBiDi</code> object.
614
* @param isInverse specifies "forward" or "inverse" Bidi operation.
617
* @see ubidi_writeReordered
618
* @see ubidi_setReorderingMode
621
U_STABLE void U_EXPORT2
622
ubidi_setInverse(UBiDi *pBiDi, UBool isInverse);
625
* Is this Bidi object set to perform the inverse Bidi algorithm?
626
* <p>Note: calling this function after setting the reordering mode with
627
* <code>ubidi_setReorderingMode</code> will return <code>TRUE</code> if the
628
* reordering mode was set to <code>#UBIDI_REORDER_INVERSE_NUMBERS_AS_L</code>,
629
* <code>FALSE</code> for all other values.</p>
631
* @param pBiDi is a <code>UBiDi</code> object.
632
* @return TRUE if the Bidi object is set to perform the inverse Bidi algorithm
633
* by handling numbers as L.
635
* @see ubidi_setInverse
636
* @see ubidi_setReorderingMode
640
U_STABLE UBool U_EXPORT2
641
ubidi_isInverse(UBiDi *pBiDi);
644
* Specify whether block separators must be allocated level zero,
645
* so that successive paragraphs will progress from left to right.
646
* This function must be called before <code>ubidi_setPara()</code>.
647
* Paragraph separators (B) may appear in the text. Setting them to level zero
648
* means that all paragraph separators (including one possibly appearing
649
* in the last text position) are kept in the reordered text after the text
650
* that they follow in the source text.
651
* When this feature is not enabled, a paragraph separator at the last
652
* position of the text before reordering will go to the first position
653
* of the reordered text when the paragraph level is odd.
655
* @param pBiDi is a <code>UBiDi</code> object.
657
* @param orderParagraphsLTR specifies whether paragraph separators (B) must
658
* receive level 0, so that successive paragraphs progress from left to right.
663
U_STABLE void U_EXPORT2
664
ubidi_orderParagraphsLTR(UBiDi *pBiDi, UBool orderParagraphsLTR);
667
* Is this Bidi object set to allocate level 0 to block separators so that
668
* successive paragraphs progress from left to right?
670
* @param pBiDi is a <code>UBiDi</code> object.
671
* @return TRUE if the Bidi object is set to allocate level 0 to block
674
* @see ubidi_orderParagraphsLTR
677
U_STABLE UBool U_EXPORT2
678
ubidi_isOrderParagraphsLTR(UBiDi *pBiDi);
681
* <code>UBiDiReorderingMode</code> values indicate which variant of the Bidi
684
* @see ubidi_setReorderingMode
687
typedef enum UBiDiReorderingMode {
688
/** Regular Logical to Visual Bidi algorithm according to Unicode.
691
UBIDI_REORDER_DEFAULT = 0,
692
/** Logical to Visual algorithm which handles numbers in a way which
693
* mimicks the behavior of Windows XP.
695
UBIDI_REORDER_NUMBERS_SPECIAL,
696
/** Logical to Visual algorithm grouping numbers with adjacent R characters
697
* (reversible algorithm).
699
UBIDI_REORDER_GROUP_NUMBERS_WITH_R,
700
/** Reorder runs only to transform a Logical LTR string to the Logical RTL
701
* string with the same display, or vice-versa.<br>
702
* If this mode is set together with option
703
* <code>#UBIDI_OPTION_INSERT_MARKS</code>, some Bidi controls in the source
704
* text may be removed and other controls may be added to produce the
705
* minimum combination which has the required display.
707
UBIDI_REORDER_RUNS_ONLY,
708
/** Visual to Logical algorithm which handles numbers like L
709
* (same algorithm as selected by <code>ubidi_setInverse(TRUE)</code>.
710
* @see ubidi_setInverse
712
UBIDI_REORDER_INVERSE_NUMBERS_AS_L,
713
/** Visual to Logical algorithm equivalent to the regular Logical to Visual
716
UBIDI_REORDER_INVERSE_LIKE_DIRECT,
717
/** Inverse Bidi (Visual to Logical) algorithm for the
718
* <code>UBIDI_REORDER_NUMBERS_SPECIAL</code> Bidi algorithm.
720
UBIDI_REORDER_INVERSE_FOR_NUMBERS_SPECIAL,
721
/** Number of values for reordering mode.
724
} UBiDiReorderingMode;
727
* Modify the operation of the Bidi algorithm such that it implements some
728
* variant to the basic Bidi algorithm or approximates an "inverse Bidi"
729
* algorithm, depending on different values of the "reordering mode".
730
* This function must be called before <code>ubidi_setPara()</code>, and stays
731
* in effect until called again with a different argument.
733
* <p>The normal operation of the Bidi algorithm as described
734
* in the Unicode Standard Annex #9 is to take text stored in logical
735
* (keyboard, typing) order and to determine how to reorder it for visual
738
* <p>With the reordering mode set to a value other than
739
* <code>#UBIDI_REORDER_DEFAULT</code>, this function changes the behavior of
740
* some of the subsequent functions in a way such that they implement an
741
* inverse Bidi algorithm or some other algorithm variants.</p>
743
* <p>Some legacy systems store text in visual order, and for operations
744
* with standard, Unicode-based algorithms, the text needs to be transformed
745
* into logical order. This is effectively the inverse algorithm of the
746
* described Bidi algorithm. Note that there is no standard algorithm for
747
* this "inverse Bidi", so a number of variants are implemented here.</p>
749
* <p>In other cases, it may be desirable to emulate some variant of the
750
* Logical to Visual algorithm (e.g. one used in MS Windows), or perform a
751
* Logical to Logical transformation.</p>
754
* <li>When the reordering mode is set to <code>#UBIDI_REORDER_DEFAULT</code>,
755
* the standard Bidi Logical to Visual algorithm is applied.</li>
757
* <li>When the reordering mode is set to
758
* <code>#UBIDI_REORDER_NUMBERS_SPECIAL</code>,
759
* the algorithm used to perform Bidi transformations when calling
760
* <code>ubidi_setPara</code> should approximate the algorithm used in
761
* Microsoft Windows XP rather than strictly conform to the Unicode Bidi
764
* The differences between the basic algorithm and the algorithm addressed
765
* by this option are as follows:
767
* <li>Within text at an even embedding level, the sequence "123AB"
768
* (where AB represent R or AL letters) is transformed to "123BA" by the
769
* Unicode algorithm and to "BA123" by the Windows algorithm.</li>
770
* <li>Arabic-Indic numbers (AN) are handled by the Windows algorithm just
771
* like regular numbers (EN).</li>
774
* <li>When the reordering mode is set to
775
* <code>#UBIDI_REORDER_GROUP_NUMBERS_WITH_R</code>,
776
* numbers located between LTR text and RTL text are associated with the RTL
777
* text. For instance, an LTR paragraph with content "abc 123 DEF" (where
778
* upper case letters represent RTL characters) will be transformed to
779
* "abc FED 123" (and not "abc 123 FED"), "DEF 123 abc" will be transformed
780
* to "123 FED abc" and "123 FED abc" will be transformed to "DEF 123 abc".
781
* This makes the algorithm reversible and makes it useful when round trip
782
* (from visual to logical and back to visual) must be achieved without
783
* adding LRM characters. However, this is a variation from the standard
784
* Unicode Bidi algorithm.<br>
785
* The source text should not contain Bidi control characters other than LRM
788
* <li>When the reordering mode is set to
789
* <code>#UBIDI_REORDER_RUNS_ONLY</code>,
790
* a "Logical to Logical" transformation must be performed:
792
* <li>If the default text level of the source text (argument <code>paraLevel</code>
793
* in <code>ubidi_setPara</code>) is even, the source text will be handled as
794
* LTR logical text and will be transformed to the RTL logical text which has
795
* the same LTR visual display.</li>
796
* <li>If the default level of the source text is odd, the source text
797
* will be handled as RTL logical text and will be transformed to the
798
* LTR logical text which has the same LTR visual display.</li>
800
* This mode may be needed when logical text which is basically Arabic or
801
* Hebrew, with possible included numbers or phrases in English, has to be
802
* displayed as if it had an even embedding level (this can happen if the
803
* displaying application treats all text as if it was basically LTR).
805
* This mode may also be needed in the reverse case, when logical text which is
806
* basically English, with possible included phrases in Arabic or Hebrew, has to
807
* be displayed as if it had an odd embedding level.
809
* Both cases could be handled by adding LRE or RLE at the head of the text,
810
* if the display subsystem supports these formatting controls. If it does not,
811
* the problem may be handled by transforming the source text in this mode
812
* before displaying it, so that it will be displayed properly.<br>
813
* The source text should not contain Bidi control characters other than LRM
816
* <li>When the reordering mode is set to
817
* <code>#UBIDI_REORDER_INVERSE_NUMBERS_AS_L</code>, an "inverse Bidi" algorithm
819
* Runs of text with numeric characters will be treated like LTR letters and
820
* may need to be surrounded with LRM characters when they are written in
821
* reordered sequence (the option <code>#UBIDI_INSERT_LRM_FOR_NUMERIC</code> can
822
* be used with function <code>ubidi_writeReordered</code> to this end. This
823
* mode is equivalent to calling <code>ubidi_setInverse()</code> with
824
* argument <code>isInverse</code> set to <code>TRUE</code>.</li>
826
* <li>When the reordering mode is set to
827
* <code>#UBIDI_REORDER_INVERSE_LIKE_DIRECT</code>, the "direct" Logical to Visual
828
* Bidi algorithm is used as an approximation of an "inverse Bidi" algorithm.
829
* This mode is similar to mode <code>#UBIDI_REORDER_INVERSE_NUMBERS_AS_L</code>
830
* but is closer to the regular Bidi algorithm.
832
* For example, an LTR paragraph with the content "FED 123 456 CBA" (where
833
* upper case represents RTL characters) will be transformed to
834
* "ABC 456 123 DEF", as opposed to "DEF 123 456 ABC"
835
* with mode <code>UBIDI_REORDER_INVERSE_NUMBERS_AS_L</code>.<br>
836
* When used in conjunction with option
837
* <code>#UBIDI_OPTION_INSERT_MARKS</code>, this mode generally
838
* adds Bidi marks to the output significantly more sparingly than mode
839
* <code>#UBIDI_REORDER_INVERSE_NUMBERS_AS_L</code> with option
840
* <code>#UBIDI_INSERT_LRM_FOR_NUMERIC</code> in calls to
841
* <code>ubidi_writeReordered</code>.</li>
843
* <li>When the reordering mode is set to
844
* <code>#UBIDI_REORDER_INVERSE_FOR_NUMBERS_SPECIAL</code>, the Logical to Visual
845
* Bidi algorithm used in Windows XP is used as an approximation of an "inverse Bidi" algorithm.
847
* For example, an LTR paragraph with the content "abc FED123" (where
848
* upper case represents RTL characters) will be transformed to "abc 123DEF."</li>
851
* <p>In all the reordering modes specifying an "inverse Bidi" algorithm
852
* (i.e. those with a name starting with <code>UBIDI_REORDER_INVERSE</code>),
853
* output runs should be retrieved using
854
* <code>ubidi_getVisualRun()</code>, and the output text with
855
* <code>ubidi_writeReordered()</code>. The caller should keep in mind that in
856
* "inverse Bidi" modes the input is actually visually ordered text and
857
* reordered output returned by <code>ubidi_getVisualRun()</code> or
858
* <code>ubidi_writeReordered()</code> are actually runs or character string
859
* of logically ordered output.<br>
860
* For all the "inverse Bidi" modes, the source text should not contain
861
* Bidi control characters other than LRM or RLM.</p>
863
* <p>Note that option <code>#UBIDI_OUTPUT_REVERSE</code> of
864
* <code>ubidi_writeReordered</code> has no useful meaning and should not be
865
* used in conjunction with any value of the reordering mode specifying
866
* "inverse Bidi" or with value <code>UBIDI_REORDER_RUNS_ONLY</code>.
868
* @param pBiDi is a <code>UBiDi</code> object.
869
* @param reorderingMode specifies the required variant of the Bidi algorithm.
871
* @see UBiDiReorderingMode
872
* @see ubidi_setInverse
874
* @see ubidi_writeReordered
877
U_STABLE void U_EXPORT2
878
ubidi_setReorderingMode(UBiDi *pBiDi, UBiDiReorderingMode reorderingMode);
881
* What is the requested reordering mode for a given Bidi object?
883
* @param pBiDi is a <code>UBiDi</code> object.
884
* @return the current reordering mode of the Bidi object
885
* @see ubidi_setReorderingMode
888
U_STABLE UBiDiReorderingMode U_EXPORT2
889
ubidi_getReorderingMode(UBiDi *pBiDi);
892
* <code>UBiDiReorderingOption</code> values indicate which options are
893
* specified to affect the Bidi algorithm.
895
* @see ubidi_setReorderingOptions
898
typedef enum UBiDiReorderingOption {
900
* option value for <code>ubidi_setReorderingOptions</code>:
901
* disable all the options which can be set with this function
902
* @see ubidi_setReorderingOptions
905
UBIDI_OPTION_DEFAULT = 0,
908
* option bit for <code>ubidi_setReorderingOptions</code>:
909
* insert Bidi marks (LRM or RLM) when needed to ensure correct result of
910
* a reordering to a Logical order
912
* <p>This option must be set or reset before calling
913
* <code>ubidi_setPara</code>.</p>
915
* <p>This option is significant only with reordering modes which generate
916
* a result with Logical order, specifically:</p>
918
* <li><code>#UBIDI_REORDER_RUNS_ONLY</code></li>
919
* <li><code>#UBIDI_REORDER_INVERSE_NUMBERS_AS_L</code></li>
920
* <li><code>#UBIDI_REORDER_INVERSE_LIKE_DIRECT</code></li>
921
* <li><code>#UBIDI_REORDER_INVERSE_FOR_NUMBERS_SPECIAL</code></li>
924
* <p>If this option is set in conjunction with reordering mode
925
* <code>#UBIDI_REORDER_INVERSE_NUMBERS_AS_L</code> or with calling
926
* <code>ubidi_setInverse(TRUE)</code>, it implies
927
* option <code>#UBIDI_INSERT_LRM_FOR_NUMERIC</code>
928
* in calls to function <code>ubidi_writeReordered()</code>.</p>
930
* <p>For other reordering modes, a minimum number of LRM or RLM characters
931
* will be added to the source text after reordering it so as to ensure
932
* round trip, i.e. when applying the inverse reordering mode on the
933
* resulting logical text with removal of Bidi marks
934
* (option <code>#UBIDI_OPTION_REMOVE_CONTROLS</code> set before calling
935
* <code>ubidi_setPara()</code> or option <code>#UBIDI_REMOVE_BIDI_CONTROLS</code>
936
* in <code>ubidi_writeReordered</code>), the result will be identical to the
937
* source text in the first transformation.
939
* <p>This option will be ignored if specified together with option
940
* <code>#UBIDI_OPTION_REMOVE_CONTROLS</code>. It inhibits option
941
* <code>UBIDI_REMOVE_BIDI_CONTROLS</code> in calls to function
942
* <code>ubidi_writeReordered()</code> and it implies option
943
* <code>#UBIDI_INSERT_LRM_FOR_NUMERIC</code> in calls to function
944
* <code>ubidi_writeReordered()</code> if the reordering mode is
945
* <code>#UBIDI_REORDER_INVERSE_NUMBERS_AS_L</code>.</p>
947
* @see ubidi_setReorderingMode
948
* @see ubidi_setReorderingOptions
951
UBIDI_OPTION_INSERT_MARKS = 1,
954
* option bit for <code>ubidi_setReorderingOptions</code>:
955
* remove Bidi control characters
957
* <p>This option must be set or reset before calling
958
* <code>ubidi_setPara</code>.</p>
960
* <p>This option nullifies option <code>#UBIDI_OPTION_INSERT_MARKS</code>.
961
* It inhibits option <code>#UBIDI_INSERT_LRM_FOR_NUMERIC</code> in calls
962
* to function <code>ubidi_writeReordered()</code> and it implies option
963
* <code>#UBIDI_REMOVE_BIDI_CONTROLS</code> in calls to that function.</p>
965
* @see ubidi_setReorderingMode
966
* @see ubidi_setReorderingOptions
969
UBIDI_OPTION_REMOVE_CONTROLS = 2,
972
* option bit for <code>ubidi_setReorderingOptions</code>:
973
* process the output as part of a stream to be continued
975
* <p>This option must be set or reset before calling
976
* <code>ubidi_setPara</code>.</p>
978
* <p>This option specifies that the caller is interested in processing large
979
* text object in parts.
980
* The results of the successive calls are expected to be concatenated by the
981
* caller. Only the call for the last part will have this option bit off.</p>
983
* <p>When this option bit is on, <code>ubidi_setPara()</code> may process
984
* less than the full source text in order to truncate the text at a meaningful
985
* boundary. The caller should call <code>ubidi_getProcessedLength()</code>
986
* immediately after calling <code>ubidi_setPara()</code> in order to
987
* determine how much of the source text has been processed.
988
* Source text beyond that length should be resubmitted in following calls to
989
* <code>ubidi_setPara</code>. The processed length may be less than
990
* the length of the source text if a character preceding the last character of
991
* the source text constitutes a reasonable boundary (like a block separator)
992
* for text to be continued.<br>
993
* If the last character of the source text constitutes a reasonable
994
* boundary, the whole text will be processed at once.<br>
995
* If nowhere in the source text there exists
996
* such a reasonable boundary, the processed length will be zero.<br>
997
* The caller should check for such an occurrence and do one of the following:
998
* <ul><li>submit a larger amount of text with a better chance to include
999
* a reasonable boundary.</li>
1000
* <li>resubmit the same text after turning off option
1001
* <code>UBIDI_OPTION_STREAMING</code>.</li></ul>
1002
* In all cases, this option should be turned off before processing the last
1003
* part of the text.</p>
1005
* <p>When the <code>UBIDI_OPTION_STREAMING</code> option is used,
1006
* it is recommended to call <code>ubidi_orderParagraphsLTR()</code> with
1007
* argument <code>orderParagraphsLTR</code> set to <code>TRUE</code> before
1008
* calling <code>ubidi_setPara</code> so that later paragraphs may be
1009
* concatenated to previous paragraphs on the right.</p>
1011
* @see ubidi_setReorderingMode
1012
* @see ubidi_setReorderingOptions
1013
* @see ubidi_getProcessedLength
1014
* @see ubidi_orderParagraphsLTR
1017
UBIDI_OPTION_STREAMING = 4
1018
} UBiDiReorderingOption;
1021
* Specify which of the reordering options
1022
* should be applied during Bidi transformations.
1024
* @param pBiDi is a <code>UBiDi</code> object.
1025
* @param reorderingOptions is a combination of zero or more of the following
1027
* <code>#UBIDI_OPTION_DEFAULT</code>, <code>#UBIDI_OPTION_INSERT_MARKS</code>,
1028
* <code>#UBIDI_OPTION_REMOVE_CONTROLS</code>, <code>#UBIDI_OPTION_STREAMING</code>.
1030
* @see ubidi_getReorderingOptions
1033
U_STABLE void U_EXPORT2
1034
ubidi_setReorderingOptions(UBiDi *pBiDi, uint32_t reorderingOptions);
1037
* What are the reordering options applied to a given Bidi object?
1039
* @param pBiDi is a <code>UBiDi</code> object.
1040
* @return the current reordering options of the Bidi object
1041
* @see ubidi_setReorderingOptions
1044
U_STABLE uint32_t U_EXPORT2
1045
ubidi_getReorderingOptions(UBiDi *pBiDi);
1048
* Perform the Unicode Bidi algorithm. It is defined in the
1049
* <a href="http://www.unicode.org/unicode/reports/tr9/">Unicode Standard Anned #9</a>,
1051
* also described in The Unicode Standard, Version 4.0 .<p>
1053
* This function takes a piece of plain text containing one or more paragraphs,
1054
* with or without externally specified embedding levels from <i>styled</i>
1055
* text and computes the left-right-directionality of each character.<p>
1057
* If the entire text is all of the same directionality, then
1058
* the function may not perform all the steps described by the algorithm,
1059
* i.e., some levels may not be the same as if all steps were performed.
1060
* This is not relevant for unidirectional text.<br>
1061
* For example, in pure LTR text with numbers the numbers would get
1062
* a resolved level of 2 higher than the surrounding text according to
1063
* the algorithm. This implementation may set all resolved levels to
1064
* the same value in such a case.<p>
1066
* The text can be composed of multiple paragraphs. Occurrence of a block
1067
* separator in the text terminates a paragraph, and whatever comes next starts
1068
* a new paragraph. The exception to this rule is when a Carriage Return (CR)
1069
* is followed by a Line Feed (LF). Both CR and LF are block separators, but
1070
* in that case, the pair of characters is considered as terminating the
1071
* preceding paragraph, and a new paragraph will be started by a character
1072
* coming after the LF.
1074
* @param pBiDi A <code>UBiDi</code> object allocated with <code>ubidi_open()</code>
1075
* which will be set to contain the reordering information,
1076
* especially the resolved levels for all the characters in <code>text</code>.
1078
* @param text is a pointer to the text that the Bidi algorithm will be performed on.
1079
* This pointer is stored in the UBiDi object and can be retrieved
1080
* with <code>ubidi_getText()</code>.<br>
1081
* <strong>Note:</strong> the text must be (at least) <code>length</code> long.
1083
* @param length is the length of the text; if <code>length==-1</code> then
1084
* the text must be zero-terminated.
1086
* @param paraLevel specifies the default level for the text;
1087
* it is typically 0 (LTR) or 1 (RTL).
1088
* If the function shall determine the paragraph level from the text,
1089
* then <code>paraLevel</code> can be set to
1090
* either <code>#UBIDI_DEFAULT_LTR</code>
1091
* or <code>#UBIDI_DEFAULT_RTL</code>; if the text contains multiple
1092
* paragraphs, the paragraph level shall be determined separately for
1093
* each paragraph; if a paragraph does not include any strongly typed
1094
* character, then the desired default is used (0 for LTR or 1 for RTL).
1095
* Any other value between 0 and <code>#UBIDI_MAX_EXPLICIT_LEVEL</code>
1096
* is also valid, with odd levels indicating RTL.
1098
* @param embeddingLevels (in) may be used to preset the embedding and override levels,
1099
* ignoring characters like LRE and PDF in the text.
1100
* A level overrides the directional property of its corresponding
1101
* (same index) character if the level has the
1102
* <code>#UBIDI_LEVEL_OVERRIDE</code> bit set.<br><br>
1103
* Except for that bit, it must be
1104
* <code>paraLevel<=embeddingLevels[]<=UBIDI_MAX_EXPLICIT_LEVEL</code>,
1105
* with one exception: a level of zero may be specified for a paragraph
1106
* separator even if <code>paraLevel>0</code> when multiple paragraphs
1107
* are submitted in the same call to <code>ubidi_setPara()</code>.<br><br>
1108
* <strong>Caution: </strong>A copy of this pointer, not of the levels,
1109
* will be stored in the <code>UBiDi</code> object;
1110
* the <code>embeddingLevels</code> array must not be
1111
* deallocated before the <code>UBiDi</code> structure is destroyed or reused,
1112
* and the <code>embeddingLevels</code>
1113
* should not be modified to avoid unexpected results on subsequent Bidi operations.
1114
* However, the <code>ubidi_setPara()</code> and
1115
* <code>ubidi_setLine()</code> functions may modify some or all of the levels.<br><br>
1116
* After the <code>UBiDi</code> object is reused or destroyed, the caller
1117
* must take care of the deallocation of the <code>embeddingLevels</code> array.<br><br>
1118
* <strong>Note:</strong> the <code>embeddingLevels</code> array must be
1119
* at least <code>length</code> long.
1120
* This pointer can be <code>NULL</code> if this
1121
* value is not necessary.
1123
* @param pErrorCode must be a valid pointer to an error code value.
1126
U_STABLE void U_EXPORT2
1127
ubidi_setPara(UBiDi *pBiDi, const UChar *text, int32_t length,
1128
UBiDiLevel paraLevel, UBiDiLevel *embeddingLevels,
1129
UErrorCode *pErrorCode);
1132
* <code>ubidi_setLine()</code> sets a <code>UBiDi</code> to
1133
* contain the reordering information, especially the resolved levels,
1134
* for all the characters in a line of text. This line of text is
1135
* specified by referring to a <code>UBiDi</code> object representing
1136
* this information for a piece of text containing one or more paragraphs,
1137
* and by specifying a range of indexes in this text.<p>
1138
* In the new line object, the indexes will range from 0 to <code>limit-start-1</code>.<p>
1140
* This is used after calling <code>ubidi_setPara()</code>
1141
* for a piece of text, and after line-breaking on that text.
1142
* It is not necessary if each paragraph is treated as a single line.<p>
1144
* After line-breaking, rules (L1) and (L2) for the treatment of
1145
* trailing WS and for reordering are performed on
1146
* a <code>UBiDi</code> object that represents a line.<p>
1148
* <strong>Important: </strong><code>pLineBiDi</code> shares data with
1149
* <code>pParaBiDi</code>.
1150
* You must destroy or reuse <code>pLineBiDi</code> before <code>pParaBiDi</code>.
1151
* In other words, you must destroy or reuse the <code>UBiDi</code> object for a line
1152
* before the object for its parent paragraph.<p>
1154
* The text pointer that was stored in <code>pParaBiDi</code> is also copied,
1155
* and <code>start</code> is added to it so that it points to the beginning of the
1156
* line for this object.
1158
* @param pParaBiDi is the parent paragraph object. It must have been set
1159
* by a successful call to ubidi_setPara.
1161
* @param start is the line's first index into the text.
1163
* @param limit is just behind the line's last index into the text
1164
* (its last index +1).<br>
1165
* It must be <code>0<=start<limit<=</code>containing paragraph limit.
1166
* If the specified line crosses a paragraph boundary, the function
1167
* will terminate with error code U_ILLEGAL_ARGUMENT_ERROR.
1169
* @param pLineBiDi is the object that will now represent a line of the text.
1171
* @param pErrorCode must be a valid pointer to an error code value.
1173
* @see ubidi_setPara
1174
* @see ubidi_getProcessedLength
1177
U_STABLE void U_EXPORT2
1178
ubidi_setLine(const UBiDi *pParaBiDi,
1179
int32_t start, int32_t limit,
1181
UErrorCode *pErrorCode);
1184
* Get the directionality of the text.
1186
* @param pBiDi is the paragraph or line <code>UBiDi</code> object.
1188
* @return a value of <code>UBIDI_LTR</code>, <code>UBIDI_RTL</code>
1189
* or <code>UBIDI_MIXED</code>
1190
* that indicates if the entire text
1191
* represented by this object is unidirectional,
1192
* and which direction, or if it is mixed-directional.
1193
* Note - The value <code>UBIDI_NEUTRAL</code> is never returned from this method.
1195
* @see UBiDiDirection
1198
U_STABLE UBiDiDirection U_EXPORT2
1199
ubidi_getDirection(const UBiDi *pBiDi);
1202
* Gets the base direction of the text provided according
1203
* to the Unicode Bidirectional Algorithm. The base direction
1204
* is derived from the first character in the string with bidirectional
1205
* character type L, R, or AL. If the first such character has type L,
1206
* <code>UBIDI_LTR</code> is returned. If the first such character has
1207
* type R or AL, <code>UBIDI_RTL</code> is returned. If the string does
1208
* not contain any character of these types, then
1209
* <code>UBIDI_NEUTRAL</code> is returned.
1211
* This is a lightweight function for use when only the base direction
1212
* is needed and no further bidi processing of the text is needed.
1214
* @param text is a pointer to the text whose base
1215
* direction is needed.
1216
* Note: the text must be (at least) @c length long.
1218
* @param length is the length of the text;
1219
* if <code>length==-1</code> then the text
1220
* must be zero-terminated.
1222
* @return <code>UBIDI_LTR</code>, <code>UBIDI_RTL</code>,
1223
* <code>UBIDI_NEUTRAL</code>
1225
* @see UBiDiDirection
1228
U_DRAFT UBiDiDirection U_EXPORT2
1229
ubidi_getBaseDirection(const UChar *text, int32_t length );
1232
* Get the pointer to the text.
1234
* @param pBiDi is the paragraph or line <code>UBiDi</code> object.
1236
* @return The pointer to the text that the UBiDi object was created for.
1238
* @see ubidi_setPara
1239
* @see ubidi_setLine
1242
U_STABLE const UChar * U_EXPORT2
1243
ubidi_getText(const UBiDi *pBiDi);
1246
* Get the length of the text.
1248
* @param pBiDi is the paragraph or line <code>UBiDi</code> object.
1250
* @return The length of the text that the UBiDi object was created for.
1253
U_STABLE int32_t U_EXPORT2
1254
ubidi_getLength(const UBiDi *pBiDi);
1257
* Get the paragraph level of the text.
1259
* @param pBiDi is the paragraph or line <code>UBiDi</code> object.
1261
* @return The paragraph level. If there are multiple paragraphs, their
1262
* level may vary if the required paraLevel is UBIDI_DEFAULT_LTR or
1263
* UBIDI_DEFAULT_RTL. In that case, the level of the first paragraph
1267
* @see ubidi_getParagraph
1268
* @see ubidi_getParagraphByIndex
1271
U_STABLE UBiDiLevel U_EXPORT2
1272
ubidi_getParaLevel(const UBiDi *pBiDi);
1275
* Get the number of paragraphs.
1277
* @param pBiDi is the paragraph or line <code>UBiDi</code> object.
1279
* @return The number of paragraphs.
1282
U_STABLE int32_t U_EXPORT2
1283
ubidi_countParagraphs(UBiDi *pBiDi);
1286
* Get a paragraph, given a position within the text.
1287
* This function returns information about a paragraph.<br>
1288
* Note: if the paragraph index is known, it is more efficient to
1289
* retrieve the paragraph information using ubidi_getParagraphByIndex().<p>
1291
* @param pBiDi is the paragraph or line <code>UBiDi</code> object.
1293
* @param charIndex is the index of a character within the text, in the
1294
* range <code>[0..ubidi_getProcessedLength(pBiDi)-1]</code>.
1296
* @param pParaStart will receive the index of the first character of the
1297
* paragraph in the text.
1298
* This pointer can be <code>NULL</code> if this
1299
* value is not necessary.
1301
* @param pParaLimit will receive the limit of the paragraph.
1302
* The l-value that you point to here may be the
1303
* same expression (variable) as the one for
1304
* <code>charIndex</code>.
1305
* This pointer can be <code>NULL</code> if this
1306
* value is not necessary.
1308
* @param pParaLevel will receive the level of the paragraph.
1309
* This pointer can be <code>NULL</code> if this
1310
* value is not necessary.
1312
* @param pErrorCode must be a valid pointer to an error code value.
1314
* @return The index of the paragraph containing the specified position.
1316
* @see ubidi_getProcessedLength
1319
U_STABLE int32_t U_EXPORT2
1320
ubidi_getParagraph(const UBiDi *pBiDi, int32_t charIndex, int32_t *pParaStart,
1321
int32_t *pParaLimit, UBiDiLevel *pParaLevel,
1322
UErrorCode *pErrorCode);
1325
* Get a paragraph, given the index of this paragraph.
1327
* This function returns information about a paragraph.<p>
1329
* @param pBiDi is the paragraph <code>UBiDi</code> object.
1331
* @param paraIndex is the number of the paragraph, in the
1332
* range <code>[0..ubidi_countParagraphs(pBiDi)-1]</code>.
1334
* @param pParaStart will receive the index of the first character of the
1335
* paragraph in the text.
1336
* This pointer can be <code>NULL</code> if this
1337
* value is not necessary.
1339
* @param pParaLimit will receive the limit of the paragraph.
1340
* This pointer can be <code>NULL</code> if this
1341
* value is not necessary.
1343
* @param pParaLevel will receive the level of the paragraph.
1344
* This pointer can be <code>NULL</code> if this
1345
* value is not necessary.
1347
* @param pErrorCode must be a valid pointer to an error code value.
1351
U_STABLE void U_EXPORT2
1352
ubidi_getParagraphByIndex(const UBiDi *pBiDi, int32_t paraIndex,
1353
int32_t *pParaStart, int32_t *pParaLimit,
1354
UBiDiLevel *pParaLevel, UErrorCode *pErrorCode);
1357
* Get the level for one character.
1359
* @param pBiDi is the paragraph or line <code>UBiDi</code> object.
1361
* @param charIndex the index of a character. It must be in the range
1362
* [0..ubidi_getProcessedLength(pBiDi)].
1364
* @return The level for the character at charIndex (0 if charIndex is not
1365
* in the valid range).
1368
* @see ubidi_getProcessedLength
1371
U_STABLE UBiDiLevel U_EXPORT2
1372
ubidi_getLevelAt(const UBiDi *pBiDi, int32_t charIndex);
1375
* Get an array of levels for each character.<p>
1377
* Note that this function may allocate memory under some
1378
* circumstances, unlike <code>ubidi_getLevelAt()</code>.
1380
* @param pBiDi is the paragraph or line <code>UBiDi</code> object, whose
1381
* text length must be strictly positive.
1383
* @param pErrorCode must be a valid pointer to an error code value.
1385
* @return The levels array for the text,
1386
* or <code>NULL</code> if an error occurs.
1389
* @see ubidi_getProcessedLength
1392
U_STABLE const UBiDiLevel * U_EXPORT2
1393
ubidi_getLevels(UBiDi *pBiDi, UErrorCode *pErrorCode);
1396
* Get a logical run.
1397
* This function returns information about a run and is used
1398
* to retrieve runs in logical order.<p>
1399
* This is especially useful for line-breaking on a paragraph.
1401
* @param pBiDi is the paragraph or line <code>UBiDi</code> object.
1403
* @param logicalPosition is a logical position within the source text.
1405
* @param pLogicalLimit will receive the limit of the corresponding run.
1406
* The l-value that you point to here may be the
1407
* same expression (variable) as the one for
1408
* <code>logicalPosition</code>.
1409
* This pointer can be <code>NULL</code> if this
1410
* value is not necessary.
1412
* @param pLevel will receive the level of the corresponding run.
1413
* This pointer can be <code>NULL</code> if this
1414
* value is not necessary.
1416
* @see ubidi_getProcessedLength
1419
U_STABLE void U_EXPORT2
1420
ubidi_getLogicalRun(const UBiDi *pBiDi, int32_t logicalPosition,
1421
int32_t *pLogicalLimit, UBiDiLevel *pLevel);
1424
* Get the number of runs.
1425
* This function may invoke the actual reordering on the
1426
* <code>UBiDi</code> object, after <code>ubidi_setPara()</code>
1427
* may have resolved only the levels of the text. Therefore,
1428
* <code>ubidi_countRuns()</code> may have to allocate memory,
1429
* and may fail doing so.
1431
* @param pBiDi is the paragraph or line <code>UBiDi</code> object.
1433
* @param pErrorCode must be a valid pointer to an error code value.
1435
* @return The number of runs.
1438
U_STABLE int32_t U_EXPORT2
1439
ubidi_countRuns(UBiDi *pBiDi, UErrorCode *pErrorCode);
1442
* Get one run's logical start, length, and directionality,
1443
* which can be 0 for LTR or 1 for RTL.
1444
* In an RTL run, the character at the logical start is
1445
* visually on the right of the displayed run.
1446
* The length is the number of characters in the run.<p>
1447
* <code>ubidi_countRuns()</code> should be called
1448
* before the runs are retrieved.
1450
* @param pBiDi is the paragraph or line <code>UBiDi</code> object.
1452
* @param runIndex is the number of the run in visual order, in the
1453
* range <code>[0..ubidi_countRuns(pBiDi)-1]</code>.
1455
* @param pLogicalStart is the first logical character index in the text.
1456
* The pointer may be <code>NULL</code> if this index is not needed.
1458
* @param pLength is the number of characters (at least one) in the run.
1459
* The pointer may be <code>NULL</code> if this is not needed.
1461
* @return the directionality of the run,
1462
* <code>UBIDI_LTR==0</code> or <code>UBIDI_RTL==1</code>,
1463
* never <code>UBIDI_MIXED</code>,
1464
* never <code>UBIDI_NEUTRAL</code>.
1466
* @see ubidi_countRuns
1471
* int32_t i, count=ubidi_countRuns(pBiDi),
1472
* logicalStart, visualIndex=0, length;
1473
* for(i=0; i<count; ++i) {
1474
* if(UBIDI_LTR==ubidi_getVisualRun(pBiDi, i, &logicalStart, &length)) {
1476
* show_char(text[logicalStart++], visualIndex++);
1477
* } while(--length>0);
1479
* logicalStart+=length; // logicalLimit
1481
* show_char(text[--logicalStart], visualIndex++);
1482
* } while(--length>0);
1488
* Note that in right-to-left runs, code like this places
1489
* second surrogates before first ones (which is generally a bad idea)
1490
* and combining characters before base characters.
1492
* Use of <code>ubidi_writeReordered()</code>, optionally with the
1493
* <code>#UBIDI_KEEP_BASE_COMBINING</code> option, can be considered in order
1494
* to avoid these issues.
1497
U_STABLE UBiDiDirection U_EXPORT2
1498
ubidi_getVisualRun(UBiDi *pBiDi, int32_t runIndex,
1499
int32_t *pLogicalStart, int32_t *pLength);
1502
* Get the visual position from a logical text position.
1503
* If such a mapping is used many times on the same
1504
* <code>UBiDi</code> object, then calling
1505
* <code>ubidi_getLogicalMap()</code> is more efficient.<p>
1507
* The value returned may be <code>#UBIDI_MAP_NOWHERE</code> if there is no
1508
* visual position because the corresponding text character is a Bidi control
1509
* removed from output by the option <code>#UBIDI_OPTION_REMOVE_CONTROLS</code>.
1511
* When the visual output is altered by using options of
1512
* <code>ubidi_writeReordered()</code> such as <code>UBIDI_INSERT_LRM_FOR_NUMERIC</code>,
1513
* <code>UBIDI_KEEP_BASE_COMBINING</code>, <code>UBIDI_OUTPUT_REVERSE</code>,
1514
* <code>UBIDI_REMOVE_BIDI_CONTROLS</code>, the visual position returned may not
1515
* be correct. It is advised to use, when possible, reordering options
1516
* such as <code>UBIDI_OPTION_INSERT_MARKS</code> and <code>UBIDI_OPTION_REMOVE_CONTROLS</code>.
1518
* Note that in right-to-left runs, this mapping places
1519
* second surrogates before first ones (which is generally a bad idea)
1520
* and combining characters before base characters.
1521
* Use of <code>ubidi_writeReordered()</code>, optionally with the
1522
* <code>#UBIDI_KEEP_BASE_COMBINING</code> option can be considered instead
1523
* of using the mapping, in order to avoid these issues.
1525
* @param pBiDi is the paragraph or line <code>UBiDi</code> object.
1527
* @param logicalIndex is the index of a character in the text.
1529
* @param pErrorCode must be a valid pointer to an error code value.
1531
* @return The visual position of this character.
1533
* @see ubidi_getLogicalMap
1534
* @see ubidi_getLogicalIndex
1535
* @see ubidi_getProcessedLength
1538
U_STABLE int32_t U_EXPORT2
1539
ubidi_getVisualIndex(UBiDi *pBiDi, int32_t logicalIndex, UErrorCode *pErrorCode);
1542
* Get the logical text position from a visual position.
1543
* If such a mapping is used many times on the same
1544
* <code>UBiDi</code> object, then calling
1545
* <code>ubidi_getVisualMap()</code> is more efficient.<p>
1547
* The value returned may be <code>#UBIDI_MAP_NOWHERE</code> if there is no
1548
* logical position because the corresponding text character is a Bidi mark
1549
* inserted in the output by option <code>#UBIDI_OPTION_INSERT_MARKS</code>.
1551
* This is the inverse function to <code>ubidi_getVisualIndex()</code>.
1553
* When the visual output is altered by using options of
1554
* <code>ubidi_writeReordered()</code> such as <code>UBIDI_INSERT_LRM_FOR_NUMERIC</code>,
1555
* <code>UBIDI_KEEP_BASE_COMBINING</code>, <code>UBIDI_OUTPUT_REVERSE</code>,
1556
* <code>UBIDI_REMOVE_BIDI_CONTROLS</code>, the logical position returned may not
1557
* be correct. It is advised to use, when possible, reordering options
1558
* such as <code>UBIDI_OPTION_INSERT_MARKS</code> and <code>UBIDI_OPTION_REMOVE_CONTROLS</code>.
1560
* @param pBiDi is the paragraph or line <code>UBiDi</code> object.
1562
* @param visualIndex is the visual position of a character.
1564
* @param pErrorCode must be a valid pointer to an error code value.
1566
* @return The index of this character in the text.
1568
* @see ubidi_getVisualMap
1569
* @see ubidi_getVisualIndex
1570
* @see ubidi_getResultLength
1573
U_STABLE int32_t U_EXPORT2
1574
ubidi_getLogicalIndex(UBiDi *pBiDi, int32_t visualIndex, UErrorCode *pErrorCode);
1577
* Get a logical-to-visual index map (array) for the characters in the UBiDi
1578
* (paragraph or line) object.
1580
* Some values in the map may be <code>#UBIDI_MAP_NOWHERE</code> if the
1581
* corresponding text characters are Bidi controls removed from the visual
1582
* output by the option <code>#UBIDI_OPTION_REMOVE_CONTROLS</code>.
1584
* When the visual output is altered by using options of
1585
* <code>ubidi_writeReordered()</code> such as <code>UBIDI_INSERT_LRM_FOR_NUMERIC</code>,
1586
* <code>UBIDI_KEEP_BASE_COMBINING</code>, <code>UBIDI_OUTPUT_REVERSE</code>,
1587
* <code>UBIDI_REMOVE_BIDI_CONTROLS</code>, the visual positions returned may not
1588
* be correct. It is advised to use, when possible, reordering options
1589
* such as <code>UBIDI_OPTION_INSERT_MARKS</code> and <code>UBIDI_OPTION_REMOVE_CONTROLS</code>.
1591
* Note that in right-to-left runs, this mapping places
1592
* second surrogates before first ones (which is generally a bad idea)
1593
* and combining characters before base characters.
1594
* Use of <code>ubidi_writeReordered()</code>, optionally with the
1595
* <code>#UBIDI_KEEP_BASE_COMBINING</code> option can be considered instead
1596
* of using the mapping, in order to avoid these issues.
1598
* @param pBiDi is the paragraph or line <code>UBiDi</code> object.
1600
* @param indexMap is a pointer to an array of <code>ubidi_getProcessedLength()</code>
1601
* indexes which will reflect the reordering of the characters.
1602
* If option <code>#UBIDI_OPTION_INSERT_MARKS</code> is set, the number
1603
* of elements allocated in <code>indexMap</code> must be no less than
1604
* <code>ubidi_getResultLength()</code>.
1605
* The array does not need to be initialized.<br><br>
1606
* The index map will result in <code>indexMap[logicalIndex]==visualIndex</code>.
1608
* @param pErrorCode must be a valid pointer to an error code value.
1610
* @see ubidi_getVisualMap
1611
* @see ubidi_getVisualIndex
1612
* @see ubidi_getProcessedLength
1613
* @see ubidi_getResultLength
1616
U_STABLE void U_EXPORT2
1617
ubidi_getLogicalMap(UBiDi *pBiDi, int32_t *indexMap, UErrorCode *pErrorCode);
1620
* Get a visual-to-logical index map (array) for the characters in the UBiDi
1621
* (paragraph or line) object.
1623
* Some values in the map may be <code>#UBIDI_MAP_NOWHERE</code> if the
1624
* corresponding text characters are Bidi marks inserted in the visual output
1625
* by the option <code>#UBIDI_OPTION_INSERT_MARKS</code>.
1627
* When the visual output is altered by using options of
1628
* <code>ubidi_writeReordered()</code> such as <code>UBIDI_INSERT_LRM_FOR_NUMERIC</code>,
1629
* <code>UBIDI_KEEP_BASE_COMBINING</code>, <code>UBIDI_OUTPUT_REVERSE</code>,
1630
* <code>UBIDI_REMOVE_BIDI_CONTROLS</code>, the logical positions returned may not
1631
* be correct. It is advised to use, when possible, reordering options
1632
* such as <code>UBIDI_OPTION_INSERT_MARKS</code> and <code>UBIDI_OPTION_REMOVE_CONTROLS</code>.
1634
* @param pBiDi is the paragraph or line <code>UBiDi</code> object.
1636
* @param indexMap is a pointer to an array of <code>ubidi_getResultLength()</code>
1637
* indexes which will reflect the reordering of the characters.
1638
* If option <code>#UBIDI_OPTION_REMOVE_CONTROLS</code> is set, the number
1639
* of elements allocated in <code>indexMap</code> must be no less than
1640
* <code>ubidi_getProcessedLength()</code>.
1641
* The array does not need to be initialized.<br><br>
1642
* The index map will result in <code>indexMap[visualIndex]==logicalIndex</code>.
1644
* @param pErrorCode must be a valid pointer to an error code value.
1646
* @see ubidi_getLogicalMap
1647
* @see ubidi_getLogicalIndex
1648
* @see ubidi_getProcessedLength
1649
* @see ubidi_getResultLength
1652
U_STABLE void U_EXPORT2
1653
ubidi_getVisualMap(UBiDi *pBiDi, int32_t *indexMap, UErrorCode *pErrorCode);
1656
* This is a convenience function that does not use a UBiDi object.
1657
* It is intended to be used for when an application has determined the levels
1658
* of objects (character sequences) and just needs to have them reordered (L2).
1659
* This is equivalent to using <code>ubidi_getLogicalMap()</code> on a
1660
* <code>UBiDi</code> object.
1662
* @param levels is an array with <code>length</code> levels that have been determined by
1665
* @param length is the number of levels in the array, or, semantically,
1666
* the number of objects to be reordered.
1667
* It must be <code>length>0</code>.
1669
* @param indexMap is a pointer to an array of <code>length</code>
1670
* indexes which will reflect the reordering of the characters.
1671
* The array does not need to be initialized.<p>
1672
* The index map will result in <code>indexMap[logicalIndex]==visualIndex</code>.
1675
U_STABLE void U_EXPORT2
1676
ubidi_reorderLogical(const UBiDiLevel *levels, int32_t length, int32_t *indexMap);
1679
* This is a convenience function that does not use a UBiDi object.
1680
* It is intended to be used for when an application has determined the levels
1681
* of objects (character sequences) and just needs to have them reordered (L2).
1682
* This is equivalent to using <code>ubidi_getVisualMap()</code> on a
1683
* <code>UBiDi</code> object.
1685
* @param levels is an array with <code>length</code> levels that have been determined by
1688
* @param length is the number of levels in the array, or, semantically,
1689
* the number of objects to be reordered.
1690
* It must be <code>length>0</code>.
1692
* @param indexMap is a pointer to an array of <code>length</code>
1693
* indexes which will reflect the reordering of the characters.
1694
* The array does not need to be initialized.<p>
1695
* The index map will result in <code>indexMap[visualIndex]==logicalIndex</code>.
1698
U_STABLE void U_EXPORT2
1699
ubidi_reorderVisual(const UBiDiLevel *levels, int32_t length, int32_t *indexMap);
1702
* Invert an index map.
1703
* The index mapping of the first map is inverted and written to
1706
* @param srcMap is an array with <code>length</code> elements
1707
* which defines the original mapping from a source array containing
1708
* <code>length</code> elements to a destination array.
1709
* Some elements of the source array may have no mapping in the
1710
* destination array. In that case, their value will be
1711
* the special value <code>UBIDI_MAP_NOWHERE</code>.
1712
* All elements must be >=0 or equal to <code>UBIDI_MAP_NOWHERE</code>.
1713
* Some elements may have a value >= <code>length</code>, if the
1714
* destination array has more elements than the source array.
1715
* There must be no duplicate indexes (two or more elements with the
1716
* same value except <code>UBIDI_MAP_NOWHERE</code>).
1718
* @param destMap is an array with a number of elements equal to 1 + the highest
1719
* value in <code>srcMap</code>.
1720
* <code>destMap</code> will be filled with the inverse mapping.
1721
* If element with index i in <code>srcMap</code> has a value k different
1722
* from <code>UBIDI_MAP_NOWHERE</code>, this means that element i of
1723
* the source array maps to element k in the destination array.
1724
* The inverse map will have value i in its k-th element.
1725
* For all elements of the destination array which do not map to
1726
* an element in the source array, the corresponding element in the
1727
* inverse map will have a value equal to <code>UBIDI_MAP_NOWHERE</code>.
1729
* @param length is the length of each array.
1730
* @see UBIDI_MAP_NOWHERE
1733
U_STABLE void U_EXPORT2
1734
ubidi_invertMap(const int32_t *srcMap, int32_t *destMap, int32_t length);
1736
/** option flags for ubidi_writeReordered() */
1739
* option bit for ubidi_writeReordered():
1740
* keep combining characters after their base characters in RTL runs
1742
* @see ubidi_writeReordered
1745
#define UBIDI_KEEP_BASE_COMBINING 1
1748
* option bit for ubidi_writeReordered():
1749
* replace characters with the "mirrored" property in RTL runs
1750
* by their mirror-image mappings
1752
* @see ubidi_writeReordered
1755
#define UBIDI_DO_MIRRORING 2
1758
* option bit for ubidi_writeReordered():
1759
* surround the run with LRMs if necessary;
1760
* this is part of the approximate "inverse Bidi" algorithm
1762
* <p>This option does not imply corresponding adjustment of the index
1765
* @see ubidi_setInverse
1766
* @see ubidi_writeReordered
1769
#define UBIDI_INSERT_LRM_FOR_NUMERIC 4
1772
* option bit for ubidi_writeReordered():
1773
* remove Bidi control characters
1774
* (this does not affect #UBIDI_INSERT_LRM_FOR_NUMERIC)
1776
* <p>This option does not imply corresponding adjustment of the index
1779
* @see ubidi_writeReordered
1782
#define UBIDI_REMOVE_BIDI_CONTROLS 8
1785
* option bit for ubidi_writeReordered():
1786
* write the output in reverse order
1788
* <p>This has the same effect as calling <code>ubidi_writeReordered()</code>
1789
* first without this option, and then calling
1790
* <code>ubidi_writeReverse()</code> without mirroring.
1791
* Doing this in the same step is faster and avoids a temporary buffer.
1792
* An example for using this option is output to a character terminal that
1793
* is designed for RTL scripts and stores text in reverse order.</p>
1795
* @see ubidi_writeReordered
1798
#define UBIDI_OUTPUT_REVERSE 16
1801
* Get the length of the source text processed by the last call to
1802
* <code>ubidi_setPara()</code>. This length may be different from the length
1803
* of the source text if option <code>#UBIDI_OPTION_STREAMING</code>
1806
* Note that whenever the length of the text affects the execution or the
1807
* result of a function, it is the processed length which must be considered,
1808
* except for <code>ubidi_setPara</code> (which receives unprocessed source
1809
* text) and <code>ubidi_getLength</code> (which returns the original length
1810
* of the source text).<br>
1811
* In particular, the processed length is the one to consider in the following
1814
* <li>maximum value of the <code>limit</code> argument of
1815
* <code>ubidi_setLine</code></li>
1816
* <li>maximum value of the <code>charIndex</code> argument of
1817
* <code>ubidi_getParagraph</code></li>
1818
* <li>maximum value of the <code>charIndex</code> argument of
1819
* <code>ubidi_getLevelAt</code></li>
1820
* <li>number of elements in the array returned by <code>ubidi_getLevels</code></li>
1821
* <li>maximum value of the <code>logicalStart</code> argument of
1822
* <code>ubidi_getLogicalRun</code></li>
1823
* <li>maximum value of the <code>logicalIndex</code> argument of
1824
* <code>ubidi_getVisualIndex</code></li>
1825
* <li>number of elements filled in the <code>*indexMap</code> argument of
1826
* <code>ubidi_getLogicalMap</code></li>
1827
* <li>length of text processed by <code>ubidi_writeReordered</code></li>
1830
* @param pBiDi is the paragraph <code>UBiDi</code> object.
1832
* @return The length of the part of the source text processed by
1833
* the last call to <code>ubidi_setPara</code>.
1834
* @see ubidi_setPara
1835
* @see UBIDI_OPTION_STREAMING
1838
U_STABLE int32_t U_EXPORT2
1839
ubidi_getProcessedLength(const UBiDi *pBiDi);
1842
* Get the length of the reordered text resulting from the last call to
1843
* <code>ubidi_setPara()</code>. This length may be different from the length
1844
* of the source text if option <code>#UBIDI_OPTION_INSERT_MARKS</code>
1845
* or option <code>#UBIDI_OPTION_REMOVE_CONTROLS</code> has been set.
1847
* This resulting length is the one to consider in the following cases:
1849
* <li>maximum value of the <code>visualIndex</code> argument of
1850
* <code>ubidi_getLogicalIndex</code></li>
1851
* <li>number of elements of the <code>*indexMap</code> argument of
1852
* <code>ubidi_getVisualMap</code></li>
1854
* Note that this length stays identical to the source text length if
1855
* Bidi marks are inserted or removed using option bits of
1856
* <code>ubidi_writeReordered</code>, or if option
1857
* <code>#UBIDI_REORDER_INVERSE_NUMBERS_AS_L</code> has been set.
1859
* @param pBiDi is the paragraph <code>UBiDi</code> object.
1861
* @return The length of the reordered text resulting from
1862
* the last call to <code>ubidi_setPara</code>.
1863
* @see ubidi_setPara
1864
* @see UBIDI_OPTION_INSERT_MARKS
1865
* @see UBIDI_OPTION_REMOVE_CONTROLS
1868
U_STABLE int32_t U_EXPORT2
1869
ubidi_getResultLength(const UBiDi *pBiDi);
1873
* value returned by <code>UBiDiClassCallback</code> callbacks when
1874
* there is no need to override the standard Bidi class for a given code point.
1875
* @see UBiDiClassCallback
1878
#define U_BIDI_CLASS_DEFAULT U_CHAR_DIRECTION_COUNT
1881
* Callback type declaration for overriding default Bidi class values with
1883
* <p>Usually, the function pointer will be propagated to a <code>UBiDi</code>
1884
* object by calling the <code>ubidi_setClassCallback()</code> function;
1885
* then the callback will be invoked by the UBA implementation any time the
1886
* class of a character is to be determined.</p>
1888
* @param context is a pointer to the callback private data.
1890
* @param c is the code point to get a Bidi class for.
1892
* @return The directional property / Bidi class for the given code point
1893
* <code>c</code> if the default class has been overridden, or
1894
* <code>#U_BIDI_CLASS_DEFAULT</code> if the standard Bidi class value
1895
* for <code>c</code> is to be used.
1896
* @see ubidi_setClassCallback
1897
* @see ubidi_getClassCallback
1900
typedef UCharDirection U_CALLCONV
1901
UBiDiClassCallback(const void *context, UChar32 c);
1906
* Retrieve the Bidi class for a given code point.
1907
* <p>If a <code>#UBiDiClassCallback</code> callback is defined and returns a
1908
* value other than <code>#U_BIDI_CLASS_DEFAULT</code>, that value is used;
1909
* otherwise the default class determination mechanism is invoked.</p>
1911
* @param pBiDi is the paragraph <code>UBiDi</code> object.
1913
* @param c is the code point whose Bidi class must be retrieved.
1915
* @return The Bidi class for character <code>c</code> based
1916
* on the given <code>pBiDi</code> instance.
1917
* @see UBiDiClassCallback
1920
U_STABLE UCharDirection U_EXPORT2
1921
ubidi_getCustomizedClass(UBiDi *pBiDi, UChar32 c);
1924
* Set the callback function and callback data used by the UBA
1925
* implementation for Bidi class determination.
1926
* <p>This may be useful for assigning Bidi classes to PUA characters, or
1927
* for special application needs. For instance, an application may want to
1928
* handle all spaces like L or R characters (according to the base direction)
1929
* when creating the visual ordering of logical lines which are part of a report
1930
* organized in columns: there should not be interaction between adjacent
1933
* @param pBiDi is the paragraph <code>UBiDi</code> object.
1935
* @param newFn is the new callback function pointer.
1937
* @param newContext is the new callback context pointer. This can be NULL.
1939
* @param oldFn fillin: Returns the old callback function pointer. This can be
1942
* @param oldContext fillin: Returns the old callback's context. This can be
1945
* @param pErrorCode must be a valid pointer to an error code value.
1947
* @see ubidi_getClassCallback
1950
U_STABLE void U_EXPORT2
1951
ubidi_setClassCallback(UBiDi *pBiDi, UBiDiClassCallback *newFn,
1952
const void *newContext, UBiDiClassCallback **oldFn,
1953
const void **oldContext, UErrorCode *pErrorCode);
1956
* Get the current callback function used for Bidi class determination.
1958
* @param pBiDi is the paragraph <code>UBiDi</code> object.
1960
* @param fn fillin: Returns the callback function pointer.
1962
* @param context fillin: Returns the callback's private context.
1964
* @see ubidi_setClassCallback
1967
U_STABLE void U_EXPORT2
1968
ubidi_getClassCallback(UBiDi *pBiDi, UBiDiClassCallback **fn, const void **context);
1971
* Take a <code>UBiDi</code> object containing the reordering
1972
* information for a piece of text (one or more paragraphs) set by
1973
* <code>ubidi_setPara()</code> or for a line of text set by
1974
* <code>ubidi_setLine()</code> and write a reordered string to the
1975
* destination buffer.
1977
* This function preserves the integrity of characters with multiple
1978
* code units and (optionally) combining characters.
1979
* Characters in RTL runs can be replaced by mirror-image characters
1980
* in the destination buffer. Note that "real" mirroring has
1981
* to be done in a rendering engine by glyph selection
1982
* and that for many "mirrored" characters there are no
1983
* Unicode characters as mirror-image equivalents.
1984
* There are also options to insert or remove Bidi control
1985
* characters; see the description of the <code>destSize</code>
1986
* and <code>options</code> parameters and of the option bit flags.
1988
* @param pBiDi A pointer to a <code>UBiDi</code> object that
1989
* is set by <code>ubidi_setPara()</code> or
1990
* <code>ubidi_setLine()</code> and contains the reordering
1991
* information for the text that it was defined for,
1992
* as well as a pointer to that text.<br><br>
1993
* The text was aliased (only the pointer was stored
1994
* without copying the contents) and must not have been modified
1995
* since the <code>ubidi_setPara()</code> call.
1997
* @param dest A pointer to where the reordered text is to be copied.
1998
* The source text and <code>dest[destSize]</code>
2001
* @param destSize The size of the <code>dest</code> buffer,
2002
* in number of UChars.
2003
* If the <code>UBIDI_INSERT_LRM_FOR_NUMERIC</code>
2004
* option is set, then the destination length could be
2006
* <code>ubidi_getLength(pBiDi)+2*ubidi_countRuns(pBiDi)</code>.
2007
* If the <code>UBIDI_REMOVE_BIDI_CONTROLS</code> option
2008
* is set, then the destination length may be less than
2009
* <code>ubidi_getLength(pBiDi)</code>.
2010
* If none of these options is set, then the destination length
2011
* will be exactly <code>ubidi_getProcessedLength(pBiDi)</code>.
2013
* @param options A bit set of options for the reordering that control
2014
* how the reordered text is written.
2015
* The options include mirroring the characters on a code
2016
* point basis and inserting LRM characters, which is used
2017
* especially for transforming visually stored text
2018
* to logically stored text (although this is still an
2019
* imperfect implementation of an "inverse Bidi" algorithm
2020
* because it uses the "forward Bidi" algorithm at its core).
2021
* The available options are:
2022
* <code>#UBIDI_DO_MIRRORING</code>,
2023
* <code>#UBIDI_INSERT_LRM_FOR_NUMERIC</code>,
2024
* <code>#UBIDI_KEEP_BASE_COMBINING</code>,
2025
* <code>#UBIDI_OUTPUT_REVERSE</code>,
2026
* <code>#UBIDI_REMOVE_BIDI_CONTROLS</code>
2028
* @param pErrorCode must be a valid pointer to an error code value.
2030
* @return The length of the output string.
2032
* @see ubidi_getProcessedLength
2035
U_STABLE int32_t U_EXPORT2
2036
ubidi_writeReordered(UBiDi *pBiDi,
2037
UChar *dest, int32_t destSize,
2039
UErrorCode *pErrorCode);
2042
* Reverse a Right-To-Left run of Unicode text.
2044
* This function preserves the integrity of characters with multiple
2045
* code units and (optionally) combining characters.
2046
* Characters can be replaced by mirror-image characters
2047
* in the destination buffer. Note that "real" mirroring has
2048
* to be done in a rendering engine by glyph selection
2049
* and that for many "mirrored" characters there are no
2050
* Unicode characters as mirror-image equivalents.
2051
* There are also options to insert or remove Bidi control
2054
* This function is the implementation for reversing RTL runs as part
2055
* of <code>ubidi_writeReordered()</code>. For detailed descriptions
2056
* of the parameters, see there.
2057
* Since no Bidi controls are inserted here, the output string length
2058
* will never exceed <code>srcLength</code>.
2060
* @see ubidi_writeReordered
2062
* @param src A pointer to the RTL run text.
2064
* @param srcLength The length of the RTL run.
2066
* @param dest A pointer to where the reordered text is to be copied.
2067
* <code>src[srcLength]</code> and <code>dest[destSize]</code>
2070
* @param destSize The size of the <code>dest</code> buffer,
2071
* in number of UChars.
2072
* If the <code>UBIDI_REMOVE_BIDI_CONTROLS</code> option
2073
* is set, then the destination length may be less than
2074
* <code>srcLength</code>.
2075
* If this option is not set, then the destination length
2076
* will be exactly <code>srcLength</code>.
2078
* @param options A bit set of options for the reordering that control
2079
* how the reordered text is written.
2080
* See the <code>options</code> parameter in <code>ubidi_writeReordered()</code>.
2082
* @param pErrorCode must be a valid pointer to an error code value.
2084
* @return The length of the output string.
2087
U_STABLE int32_t U_EXPORT2
2088
ubidi_writeReverse(const UChar *src, int32_t srcLength,
2089
UChar *dest, int32_t destSize,
2091
UErrorCode *pErrorCode);
2093
/*#define BIDI_SAMPLE_CODE*/