1// © 2016 and later: Unicode, Inc. and others.
2// License & terms of use: http://www.unicode.org/copyright.html
3/*
4******************************************************************************
5*
6* Copyright (C) 1999-2013, International Business Machines
7* Corporation and others. All Rights Reserved.
8*
9******************************************************************************
10* file name: ubidi.h
11* encoding: UTF-8
12* tab size: 8 (not used)
13* indentation:4
14*
15* created on: 1999jul27
16* created by: Markus W. Scherer, updated by Matitiahu Allouche
17*/
18
19#ifndef UBIDI_H
20#define UBIDI_H
21
22#include "unicode/utypes.h"
23#include "unicode/uchar.h"
24
25#if U_SHOW_CPLUSPLUS_API
26#include "unicode/localpointer.h"
27#endif // U_SHOW_CPLUSPLUS_API
28
29/**
30 *\file
31 * \brief C API: Bidi algorithm
32 *
33 * <h2>Bidi algorithm for ICU</h2>
34 *
35 * This is an implementation of the Unicode Bidirectional Algorithm.
36 * The algorithm is defined in the
37 * <a href="http://www.unicode.org/unicode/reports/tr9/">Unicode Standard Annex #9</a>.<p>
38 *
39 * Note: Libraries that perform a bidirectional algorithm and
40 * reorder strings accordingly are sometimes called "Storage Layout Engines".
41 * ICU's Bidi and shaping (u_shapeArabic()) APIs can be used at the core of such
42 * "Storage Layout Engines".
43 *
44 * <h3>General remarks about the API:</h3>
45 *
46 * In functions with an error code parameter,
47 * the <code>pErrorCode</code> pointer must be valid
48 * and the value that it points to must not indicate a failure before
49 * the function call. Otherwise, the function returns immediately.
50 * After the function call, the value indicates success or failure.<p>
51 *
52 * The &quot;limit&quot; of a sequence of characters is the position just after their
53 * last character, i.e., one more than that position.<p>
54 *
55 * Some of the API functions provide access to &quot;runs&quot;.
56 * Such a &quot;run&quot; is defined as a sequence of characters
57 * that are at the same embedding level
58 * after performing the Bidi algorithm.<p>
59 *
60 * @author Markus W. Scherer
61 * @version 1.0
62 *
63 *
64 * <h4> Sample code for the ICU Bidi API </h4>
65 *
66 * <h5>Rendering a paragraph with the ICU Bidi API</h5>
67 *
68 * This is (hypothetical) sample code that illustrates
69 * how the ICU Bidi API could be used to render a paragraph of text.
70 * Rendering code depends highly on the graphics system,
71 * therefore this sample code must make a lot of assumptions,
72 * which may or may not match any existing graphics system's properties.
73 *
74 * <p>The basic assumptions are:</p>
75 * <ul>
76 * <li>Rendering is done from left to right on a horizontal line.</li>
77 * <li>A run of single-style, unidirectional text can be rendered at once.</li>
78 * <li>Such a run of text is passed to the graphics system with
79 * characters (code units) in logical order.</li>
80 * <li>The line-breaking algorithm is very complicated
81 * and Locale-dependent -
82 * and therefore its implementation omitted from this sample code.</li>
83 * </ul>
84 *
85 * <pre>
86 * \code
87 *#include <unicode/ubidi.h>
88 *
89 *typedef enum {
90 * styleNormal=0, styleSelected=1,
91 * styleBold=2, styleItalics=4,
92 * styleSuper=8, styleSub=16
93 *} Style;
94 *
95 *typedef struct { int32_t limit; Style style; } StyleRun;
96 *
97 *int getTextWidth(const UChar *text, int32_t start, int32_t limit,
98 * const StyleRun *styleRuns, int styleRunCount);
99 *
100 * // set *pLimit and *pStyleRunLimit for a line
101 * // from text[start] and from styleRuns[styleRunStart]
102 * // using ubidi_getLogicalRun(para, ...)
103 *void getLineBreak(const UChar *text, int32_t start, int32_t *pLimit,
104 * UBiDi *para,
105 * const StyleRun *styleRuns, int styleRunStart, int *pStyleRunLimit,
106 * int *pLineWidth);
107 *
108 * // render runs on a line sequentially, always from left to right
109 *
110 * // prepare rendering a new line
111 * void startLine(UBiDiDirection textDirection, int lineWidth);
112 *
113 * // render a run of text and advance to the right by the run width
114 * // the text[start..limit-1] is always in logical order
115 * void renderRun(const UChar *text, int32_t start, int32_t limit,
116 * UBiDiDirection textDirection, Style style);
117 *
118 * // We could compute a cross-product
119 * // from the style runs with the directional runs
120 * // and then reorder it.
121 * // Instead, here we iterate over each run type
122 * // and render the intersections -
123 * // with shortcuts in simple (and common) cases.
124 * // renderParagraph() is the main function.
125 *
126 * // render a directional run with
127 * // (possibly) multiple style runs intersecting with it
128 * void renderDirectionalRun(const UChar *text,
129 * int32_t start, int32_t limit,
130 * UBiDiDirection direction,
131 * const StyleRun *styleRuns, int styleRunCount) {
132 * int i;
133 *
134 * // iterate over style runs
135 * if(direction==UBIDI_LTR) {
136 * int styleLimit;
137 *
138 * for(i=0; i<styleRunCount; ++i) {
139 * styleLimit=styleRuns[i].limit;
140 * if(start<styleLimit) {
141 * if(styleLimit>limit) { styleLimit=limit; }
142 * renderRun(text, start, styleLimit,
143 * direction, styleRuns[i].style);
144 * if(styleLimit==limit) { break; }
145 * start=styleLimit;
146 * }
147 * }
148 * } else {
149 * int styleStart;
150 *
151 * for(i=styleRunCount-1; i>=0; --i) {
152 * if(i>0) {
153 * styleStart=styleRuns[i-1].limit;
154 * } else {
155 * styleStart=0;
156 * }
157 * if(limit>=styleStart) {
158 * if(styleStart<start) { styleStart=start; }
159 * renderRun(text, styleStart, limit,
160 * direction, styleRuns[i].style);
161 * if(styleStart==start) { break; }
162 * limit=styleStart;
163 * }
164 * }
165 * }
166 * }
167 *
168 * // the line object represents text[start..limit-1]
169 * void renderLine(UBiDi *line, const UChar *text,
170 * int32_t start, int32_t limit,
171 * const StyleRun *styleRuns, int styleRunCount,
172 * UErrorCode *pErrorCode) {
173 * UBiDiDirection direction=ubidi_getDirection(line);
174 * if(direction!=UBIDI_MIXED) {
175 * // unidirectional
176 * if(styleRunCount<=1) {
177 * renderRun(text, start, limit, direction, styleRuns[0].style);
178 * } else {
179 * renderDirectionalRun(text, start, limit,
180 * direction, styleRuns, styleRunCount);
181 * }
182 * } else {
183 * // mixed-directional
184 * int32_t count, i, length;
185 * UBiDiLevel level;
186 *
187 * count=ubidi_countRuns(line, pErrorCode);
188 * if(U_SUCCESS(*pErrorCode)) {
189 * if(styleRunCount<=1) {
190 * Style style=styleRuns[0].style;
191 *
192 * // iterate over directional runs
193 * for(i=0; i<count; ++i) {
194 * direction=ubidi_getVisualRun(line, i, &start, &length);
195 * renderRun(text, start, start+length, direction, style);
196 * }
197 * } else {
198 * int32_t j;
199 *
200 * // iterate over both directional and style runs
201 * for(i=0; i<count; ++i) {
202 * direction=ubidi_getVisualRun(line, i, &start, &length);
203 * renderDirectionalRun(text, start, start+length,
204 * direction, styleRuns, styleRunCount);
205 * }
206 * }
207 * }
208 * }
209 * }
210 *
211 *void renderParagraph(const UChar *text, int32_t length,
212 * UBiDiDirection textDirection,
213 * const StyleRun *styleRuns, int styleRunCount,
214 * int lineWidth,
215 * UErrorCode *pErrorCode) {
216 * UBiDi *para;
217 *
218 * if(pErrorCode==NULL || U_FAILURE(*pErrorCode) || length<=0) {
219 * return;
220 * }
221 *
222 * para=ubidi_openSized(length, 0, pErrorCode);
223 * if(para==NULL) { return; }
224 *
225 * ubidi_setPara(para, text, length,
226 * textDirection ? UBIDI_DEFAULT_RTL : UBIDI_DEFAULT_LTR,
227 * NULL, pErrorCode);
228 * if(U_SUCCESS(*pErrorCode)) {
229 * UBiDiLevel paraLevel=1&ubidi_getParaLevel(para);
230 * StyleRun styleRun={ length, styleNormal };
231 * int width;
232 *
233 * if(styleRuns==NULL || styleRunCount<=0) {
234 * styleRunCount=1;
235 * styleRuns=&styleRun;
236 * }
237 *
238 * // assume styleRuns[styleRunCount-1].limit>=length
239 *
240 * width=getTextWidth(text, 0, length, styleRuns, styleRunCount);
241 * if(width<=lineWidth) {
242 * // everything fits onto one line
243 *
244 * // prepare rendering a new line from either left or right
245 * startLine(paraLevel, width);
246 *
247 * renderLine(para, text, 0, length,
248 * styleRuns, styleRunCount, pErrorCode);
249 * } else {
250 * UBiDi *line;
251 *
252 * // we need to render several lines
253 * line=ubidi_openSized(length, 0, pErrorCode);
254 * if(line!=NULL) {
255 * int32_t start=0, limit;
256 * int styleRunStart=0, styleRunLimit;
257 *
258 * for(;;) {
259 * limit=length;
260 * styleRunLimit=styleRunCount;
261 * getLineBreak(text, start, &limit, para,
262 * styleRuns, styleRunStart, &styleRunLimit,
263 * &width);
264 * ubidi_setLine(para, start, limit, line, pErrorCode);
265 * if(U_SUCCESS(*pErrorCode)) {
266 * // prepare rendering a new line
267 * // from either left or right
268 * startLine(paraLevel, width);
269 *
270 * renderLine(line, text, start, limit,
271 * styleRuns+styleRunStart,
272 * styleRunLimit-styleRunStart, pErrorCode);
273 * }
274 * if(limit==length) { break; }
275 * start=limit;
276 * styleRunStart=styleRunLimit-1;
277 * if(start>=styleRuns[styleRunStart].limit) {
278 * ++styleRunStart;
279 * }
280 * }
281 *
282 * ubidi_close(line);
283 * }
284 * }
285 * }
286 *
287 * ubidi_close(para);
288 *}
289 *\endcode
290 * </pre>
291 */
292
293/*DOCXX_TAG*/
294/*@{*/
295
296/**
297 * UBiDiLevel is the type of the level values in this
298 * Bidi implementation.
299 * It holds an embedding level and indicates the visual direction
300 * by its bit&nbsp;0 (even/odd value).<p>
301 *
302 * It can also hold non-level values for the
303 * <code>paraLevel</code> and <code>embeddingLevels</code>
304 * arguments of <code>ubidi_setPara()</code>; there:
305 * <ul>
306 * <li>bit&nbsp;7 of an <code>embeddingLevels[]</code>
307 * value indicates whether the using application is
308 * specifying the level of a character to <i>override</i> whatever the
309 * Bidi implementation would resolve it to.</li>
310 * <li><code>paraLevel</code> can be set to the
311 * pseudo-level values <code>UBIDI_DEFAULT_LTR</code>
312 * and <code>UBIDI_DEFAULT_RTL</code>.</li>
313 * </ul>
314 *
315 * @see ubidi_setPara
316 *
317 * <p>The related constants are not real, valid level values.
318 * <code>UBIDI_DEFAULT_XXX</code> can be used to specify
319 * a default for the paragraph level for
320 * when the <code>ubidi_setPara()</code> function
321 * shall determine it but there is no
322 * strongly typed character in the input.<p>
323 *
324 * Note that the value for <code>UBIDI_DEFAULT_LTR</code> is even
325 * and the one for <code>UBIDI_DEFAULT_RTL</code> is odd,
326 * just like with normal LTR and RTL level values -
327 * these special values are designed that way. Also, the implementation
328 * assumes that UBIDI_MAX_EXPLICIT_LEVEL is odd.
329 *
330 * Note: The numeric values of the related constants will not change:
331 * They are tied to the use of 7-bit byte values (plus the override bit)
332 * and of the UBiDiLevel=uint8_t data type in this API.
333 *
334 * @see UBIDI_DEFAULT_LTR
335 * @see UBIDI_DEFAULT_RTL
336 * @see UBIDI_LEVEL_OVERRIDE
337 * @see UBIDI_MAX_EXPLICIT_LEVEL
338 * @stable ICU 2.0
339 */
340typedef uint8_t UBiDiLevel;
341
342/** Paragraph level setting.<p>
343 *
344 * Constant indicating that the base direction depends on the first strong
345 * directional character in the text according to the Unicode Bidirectional
346 * Algorithm. If no strong directional character is present,
347 * then set the paragraph level to 0 (left-to-right).<p>
348 *
349 * If this value is used in conjunction with reordering modes
350 * <code>UBIDI_REORDER_INVERSE_LIKE_DIRECT</code> or
351 * <code>UBIDI_REORDER_INVERSE_FOR_NUMBERS_SPECIAL</code>, the text to reorder
352 * is assumed to be visual LTR, and the text after reordering is required
353 * to be the corresponding logical string with appropriate contextual
354 * direction. The direction of the result string will be RTL if either
355 * the righmost or leftmost strong character of the source text is RTL
356 * or Arabic Letter, the direction will be LTR otherwise.<p>
357 *
358 * If reordering option <code>UBIDI_OPTION_INSERT_MARKS</code> is set, an RLM may
359 * be added at the beginning of the result string to ensure round trip
360 * (that the result string, when reordered back to visual, will produce
361 * the original source text).
362 * @see UBIDI_REORDER_INVERSE_LIKE_DIRECT
363 * @see UBIDI_REORDER_INVERSE_FOR_NUMBERS_SPECIAL
364 * @stable ICU 2.0
365 */
366#define UBIDI_DEFAULT_LTR 0xfe
367
368/** Paragraph level setting.<p>
369 *
370 * Constant indicating that the base direction depends on the first strong
371 * directional character in the text according to the Unicode Bidirectional
372 * Algorithm. If no strong directional character is present,
373 * then set the paragraph level to 1 (right-to-left).<p>
374 *
375 * If this value is used in conjunction with reordering modes
376 * <code>UBIDI_REORDER_INVERSE_LIKE_DIRECT</code> or
377 * <code>UBIDI_REORDER_INVERSE_FOR_NUMBERS_SPECIAL</code>, the text to reorder
378 * is assumed to be visual LTR, and the text after reordering is required
379 * to be the corresponding logical string with appropriate contextual
380 * direction. The direction of the result string will be RTL if either
381 * the righmost or leftmost strong character of the source text is RTL
382 * or Arabic Letter, or if the text contains no strong character;
383 * the direction will be LTR otherwise.<p>
384 *
385 * If reordering option <code>UBIDI_OPTION_INSERT_MARKS</code> is set, an RLM may
386 * be added at the beginning of the result string to ensure round trip
387 * (that the result string, when reordered back to visual, will produce
388 * the original source text).
389 * @see UBIDI_REORDER_INVERSE_LIKE_DIRECT
390 * @see UBIDI_REORDER_INVERSE_FOR_NUMBERS_SPECIAL
391 * @stable ICU 2.0
392 */
393#define UBIDI_DEFAULT_RTL 0xff
394
395/**
396 * Maximum explicit embedding level.
397 * Same as the max_depth value in the
398 * <a href="http://www.unicode.org/reports/tr9/#BD2">Unicode Bidirectional Algorithm</a>.
399 * (The maximum resolved level can be up to <code>UBIDI_MAX_EXPLICIT_LEVEL+1</code>).
400 * @stable ICU 2.0
401 */
402#define UBIDI_MAX_EXPLICIT_LEVEL 125
403
404/** Bit flag for level input.
405 * Overrides directional properties.
406 * @stable ICU 2.0
407 */
408#define UBIDI_LEVEL_OVERRIDE 0x80
409
410/**
411 * Special value which can be returned by the mapping functions when a logical
412 * index has no corresponding visual index or vice-versa. This may happen
413 * for the logical-to-visual mapping of a Bidi control when option
414 * <code>#UBIDI_OPTION_REMOVE_CONTROLS</code> is specified. This can also happen
415 * for the visual-to-logical mapping of a Bidi mark (LRM or RLM) inserted
416 * by option <code>#UBIDI_OPTION_INSERT_MARKS</code>.
417 * @see ubidi_getVisualIndex
418 * @see ubidi_getVisualMap
419 * @see ubidi_getLogicalIndex
420 * @see ubidi_getLogicalMap
421 * @stable ICU 3.6
422 */
423#define UBIDI_MAP_NOWHERE (-1)
424
425/**
426 * <code>UBiDiDirection</code> values indicate the text direction.
427 * @stable ICU 2.0
428 */
429enum UBiDiDirection {
430 /** Left-to-right text. This is a 0 value.
431 * <ul>
432 * <li>As return value for <code>ubidi_getDirection()</code>, it means
433 * that the source string contains no right-to-left characters, or
434 * that the source string is empty and the paragraph level is even.
435 * <li> As return value for <code>ubidi_getBaseDirection()</code>, it
436 * means that the first strong character of the source string has
437 * a left-to-right direction.
438 * </ul>
439 * @stable ICU 2.0
440 */
441 UBIDI_LTR,
442 /** Right-to-left text. This is a 1 value.
443 * <ul>
444 * <li>As return value for <code>ubidi_getDirection()</code>, it means
445 * that the source string contains no left-to-right characters, or
446 * that the source string is empty and the paragraph level is odd.
447 * <li> As return value for <code>ubidi_getBaseDirection()</code>, it
448 * means that the first strong character of the source string has
449 * a right-to-left direction.
450 * </ul>
451 * @stable ICU 2.0
452 */
453 UBIDI_RTL,
454 /** Mixed-directional text.
455 * <p>As return value for <code>ubidi_getDirection()</code>, it means
456 * that the source string contains both left-to-right and
457 * right-to-left characters.
458 * @stable ICU 2.0
459 */
460 UBIDI_MIXED,
461 /** No strongly directional text.
462 * <p>As return value for <code>ubidi_getBaseDirection()</code>, it means
463 * that the source string is missing or empty, or contains neither left-to-right
464 * nor right-to-left characters.
465 * @stable ICU 4.6
466 */
467 UBIDI_NEUTRAL
468};
469
470/** @stable ICU 2.0 */
471typedef enum UBiDiDirection UBiDiDirection;
472
473/**
474 * Forward declaration of the <code>UBiDi</code> structure for the declaration of
475 * the API functions. Its fields are implementation-specific.<p>
476 * This structure holds information about a paragraph (or multiple paragraphs)
477 * of text with Bidi-algorithm-related details, or about one line of
478 * such a paragraph.<p>
479 * Reordering can be done on a line, or on one or more paragraphs which are
480 * then interpreted each as one single line.
481 * @stable ICU 2.0
482 */
483struct UBiDi;
484
485/** @stable ICU 2.0 */
486typedef struct UBiDi UBiDi;
487
488/**
489 * Allocate a <code>UBiDi</code> structure.
490 * Such an object is initially empty. It is assigned
491 * the Bidi properties of a piece of text containing one or more paragraphs
492 * by <code>ubidi_setPara()</code>
493 * or the Bidi properties of a line within a paragraph by
494 * <code>ubidi_setLine()</code>.<p>
495 * This object can be reused for as long as it is not deallocated
496 * by calling <code>ubidi_close()</code>.<p>
497 * <code>ubidi_setPara()</code> and <code>ubidi_setLine()</code> will allocate
498 * additional memory for internal structures as necessary.
499 *
500 * @return An empty <code>UBiDi</code> object.
501 * @stable ICU 2.0
502 */
503U_CAPI UBiDi * U_EXPORT2
504ubidi_open(void);
505
506/**
507 * Allocate a <code>UBiDi</code> structure with preallocated memory
508 * for internal structures.
509 * This function provides a <code>UBiDi</code> object like <code>ubidi_open()</code>
510 * with no arguments, but it also preallocates memory for internal structures
511 * according to the sizings supplied by the caller.<p>
512 * Subsequent functions will not allocate any more memory, and are thus
513 * guaranteed not to fail because of lack of memory.<p>
514 * The preallocation can be limited to some of the internal memory
515 * by setting some values to 0 here. That means that if, e.g.,
516 * <code>maxRunCount</code> cannot be reasonably predetermined and should not
517 * be set to <code>maxLength</code> (the only failproof value) to avoid
518 * wasting memory, then <code>maxRunCount</code> could be set to 0 here
519 * and the internal structures that are associated with it will be allocated
520 * on demand, just like with <code>ubidi_open()</code>.
521 *
522 * @param maxLength is the maximum text or line length that internal memory
523 * will be preallocated for. An attempt to associate this object with a
524 * longer text will fail, unless this value is 0, which leaves the allocation
525 * up to the implementation.
526 *
527 * @param maxRunCount is the maximum anticipated number of same-level runs
528 * that internal memory will be preallocated for. An attempt to access
529 * visual runs on an object that was not preallocated for as many runs
530 * as the text was actually resolved to will fail,
531 * unless this value is 0, which leaves the allocation up to the implementation.<br><br>
532 * The number of runs depends on the actual text and maybe anywhere between
533 * 1 and <code>maxLength</code>. It is typically small.
534 *
535 * @param pErrorCode must be a valid pointer to an error code value.
536 *
537 * @return An empty <code>UBiDi</code> object with preallocated memory.
538 * @stable ICU 2.0
539 */
540U_CAPI UBiDi * U_EXPORT2
541ubidi_openSized(int32_t maxLength, int32_t maxRunCount, UErrorCode *pErrorCode);
542
543/**
544 * <code>ubidi_close()</code> must be called to free the memory
545 * associated with a UBiDi object.<p>
546 *
547 * <strong>Important: </strong>
548 * A parent <code>UBiDi</code> object must not be destroyed or reused if
549 * it still has children.
550 * If a <code>UBiDi</code> object has become the <i>child</i>
551 * of another one (its <i>parent</i>) by calling
552 * <code>ubidi_setLine()</code>, then the child object must
553 * be destroyed (closed) or reused (by calling
554 * <code>ubidi_setPara()</code> or <code>ubidi_setLine()</code>)
555 * before the parent object.
556 *
557 * @param pBiDi is a <code>UBiDi</code> object.
558 *
559 * @see ubidi_setPara
560 * @see ubidi_setLine
561 * @stable ICU 2.0
562 */
563U_CAPI void U_EXPORT2
564ubidi_close(UBiDi *pBiDi);
565
566#if U_SHOW_CPLUSPLUS_API
567
568U_NAMESPACE_BEGIN
569
570/**
571 * \class LocalUBiDiPointer
572 * "Smart pointer" class, closes a UBiDi via ubidi_close().
573 * For most methods see the LocalPointerBase base class.
574 *
575 * @see LocalPointerBase
576 * @see LocalPointer
577 * @stable ICU 4.4
578 */
579U_DEFINE_LOCAL_OPEN_POINTER(LocalUBiDiPointer, UBiDi, ubidi_close);
580
581U_NAMESPACE_END
582
583#endif
584
585/**
586 * Modify the operation of the Bidi algorithm such that it
587 * approximates an "inverse Bidi" algorithm. This function
588 * must be called before <code>ubidi_setPara()</code>.
589 *
590 * <p>The normal operation of the Bidi algorithm as described
591 * in the Unicode Technical Report is to take text stored in logical
592 * (keyboard, typing) order and to determine the reordering of it for visual
593 * rendering.
594 * Some legacy systems store text in visual order, and for operations
595 * with standard, Unicode-based algorithms, the text needs to be transformed
596 * to logical order. This is effectively the inverse algorithm of the
597 * described Bidi algorithm. Note that there is no standard algorithm for
598 * this "inverse Bidi" and that the current implementation provides only an
599 * approximation of "inverse Bidi".</p>
600 *
601 * <p>With <code>isInverse</code> set to <code>true</code>,
602 * this function changes the behavior of some of the subsequent functions
603 * in a way that they can be used for the inverse Bidi algorithm.
604 * Specifically, runs of text with numeric characters will be treated in a
605 * special way and may need to be surrounded with LRM characters when they are
606 * written in reordered sequence.</p>
607 *
608 * <p>Output runs should be retrieved using <code>ubidi_getVisualRun()</code>.
609 * Since the actual input for "inverse Bidi" is visually ordered text and
610 * <code>ubidi_getVisualRun()</code> gets the reordered runs, these are actually
611 * the runs of the logically ordered output.</p>
612 *
613 * <p>Calling this function with argument <code>isInverse</code> set to
614 * <code>true</code> is equivalent to calling
615 * <code>ubidi_setReorderingMode</code> with argument
616 * <code>reorderingMode</code>
617 * set to <code>#UBIDI_REORDER_INVERSE_NUMBERS_AS_L</code>.<br>
618 * Calling this function with argument <code>isInverse</code> set to
619 * <code>false</code> is equivalent to calling
620 * <code>ubidi_setReorderingMode</code> with argument
621 * <code>reorderingMode</code>
622 * set to <code>#UBIDI_REORDER_DEFAULT</code>.
623 *
624 * @param pBiDi is a <code>UBiDi</code> object.
625 *
626 * @param isInverse specifies "forward" or "inverse" Bidi operation.
627 *
628 * @see ubidi_setPara
629 * @see ubidi_writeReordered
630 * @see ubidi_setReorderingMode
631 * @stable ICU 2.0
632 */
633U_CAPI void U_EXPORT2
634ubidi_setInverse(UBiDi *pBiDi, UBool isInverse);
635
636/**
637 * Is this Bidi object set to perform the inverse Bidi algorithm?
638 * <p>Note: calling this function after setting the reordering mode with
639 * <code>ubidi_setReorderingMode</code> will return <code>true</code> if the
640 * reordering mode was set to <code>#UBIDI_REORDER_INVERSE_NUMBERS_AS_L</code>,
641 * <code>false</code> for all other values.</p>
642 *
643 * @param pBiDi is a <code>UBiDi</code> object.
644 * @return true if the Bidi object is set to perform the inverse Bidi algorithm
645 * by handling numbers as L.
646 *
647 * @see ubidi_setInverse
648 * @see ubidi_setReorderingMode
649 * @stable ICU 2.0
650 */
651
652U_CAPI UBool U_EXPORT2
653ubidi_isInverse(UBiDi *pBiDi);
654
655/**
656 * Specify whether block separators must be allocated level zero,
657 * so that successive paragraphs will progress from left to right.
658 * This function must be called before <code>ubidi_setPara()</code>.
659 * Paragraph separators (B) may appear in the text. Setting them to level zero
660 * means that all paragraph separators (including one possibly appearing
661 * in the last text position) are kept in the reordered text after the text
662 * that they follow in the source text.
663 * When this feature is not enabled, a paragraph separator at the last
664 * position of the text before reordering will go to the first position
665 * of the reordered text when the paragraph level is odd.
666 *
667 * @param pBiDi is a <code>UBiDi</code> object.
668 *
669 * @param orderParagraphsLTR specifies whether paragraph separators (B) must
670 * receive level 0, so that successive paragraphs progress from left to right.
671 *
672 * @see ubidi_setPara
673 * @stable ICU 3.4
674 */
675U_CAPI void U_EXPORT2
676ubidi_orderParagraphsLTR(UBiDi *pBiDi, UBool orderParagraphsLTR);
677
678/**
679 * Is this Bidi object set to allocate level 0 to block separators so that
680 * successive paragraphs progress from left to right?
681 *
682 * @param pBiDi is a <code>UBiDi</code> object.
683 * @return true if the Bidi object is set to allocate level 0 to block
684 * separators.
685 *
686 * @see ubidi_orderParagraphsLTR
687 * @stable ICU 3.4
688 */
689U_CAPI UBool U_EXPORT2
690ubidi_isOrderParagraphsLTR(UBiDi *pBiDi);
691
692/**
693 * <code>UBiDiReorderingMode</code> values indicate which variant of the Bidi
694 * algorithm to use.
695 *
696 * @see ubidi_setReorderingMode
697 * @stable ICU 3.6
698 */
699typedef enum UBiDiReorderingMode {
700 /** Regular Logical to Visual Bidi algorithm according to Unicode.
701 * This is a 0 value.
702 * @stable ICU 3.6 */
703 UBIDI_REORDER_DEFAULT = 0,
704 /** Logical to Visual algorithm which handles numbers in a way which
705 * mimics the behavior of Windows XP.
706 * @stable ICU 3.6 */
707 UBIDI_REORDER_NUMBERS_SPECIAL,
708 /** Logical to Visual algorithm grouping numbers with adjacent R characters
709 * (reversible algorithm).
710 * @stable ICU 3.6 */
711 UBIDI_REORDER_GROUP_NUMBERS_WITH_R,
712 /** Reorder runs only to transform a Logical LTR string to the Logical RTL
713 * string with the same display, or vice-versa.<br>
714 * If this mode is set together with option
715 * <code>#UBIDI_OPTION_INSERT_MARKS</code>, some Bidi controls in the source
716 * text may be removed and other controls may be added to produce the
717 * minimum combination which has the required display.
718 * @stable ICU 3.6 */
719 UBIDI_REORDER_RUNS_ONLY,
720 /** Visual to Logical algorithm which handles numbers like L
721 * (same algorithm as selected by <code>ubidi_setInverse(true)</code>.
722 * @see ubidi_setInverse
723 * @stable ICU 3.6 */
724 UBIDI_REORDER_INVERSE_NUMBERS_AS_L,
725 /** Visual to Logical algorithm equivalent to the regular Logical to Visual
726 * algorithm.
727 * @stable ICU 3.6 */
728 UBIDI_REORDER_INVERSE_LIKE_DIRECT,
729 /** Inverse Bidi (Visual to Logical) algorithm for the
730 * <code>UBIDI_REORDER_NUMBERS_SPECIAL</code> Bidi algorithm.
731 * @stable ICU 3.6 */
732 UBIDI_REORDER_INVERSE_FOR_NUMBERS_SPECIAL,
733#ifndef U_HIDE_DEPRECATED_API
734 /**
735 * Number of values for reordering mode.
736 * @deprecated ICU 58 The numeric value may change over time, see ICU ticket #12420.
737 */
738 UBIDI_REORDER_COUNT
739#endif // U_HIDE_DEPRECATED_API
740} UBiDiReorderingMode;
741
742/**
743 * Modify the operation of the Bidi algorithm such that it implements some
744 * variant to the basic Bidi algorithm or approximates an "inverse Bidi"
745 * algorithm, depending on different values of the "reordering mode".
746 * This function must be called before <code>ubidi_setPara()</code>, and stays
747 * in effect until called again with a different argument.
748 *
749 * <p>The normal operation of the Bidi algorithm as described
750 * in the Unicode Standard Annex #9 is to take text stored in logical
751 * (keyboard, typing) order and to determine how to reorder it for visual
752 * rendering.</p>
753 *
754 * <p>With the reordering mode set to a value other than
755 * <code>#UBIDI_REORDER_DEFAULT</code>, this function changes the behavior of
756 * some of the subsequent functions in a way such that they implement an
757 * inverse Bidi algorithm or some other algorithm variants.</p>
758 *
759 * <p>Some legacy systems store text in visual order, and for operations
760 * with standard, Unicode-based algorithms, the text needs to be transformed
761 * into logical order. This is effectively the inverse algorithm of the
762 * described Bidi algorithm. Note that there is no standard algorithm for
763 * this "inverse Bidi", so a number of variants are implemented here.</p>
764 *
765 * <p>In other cases, it may be desirable to emulate some variant of the
766 * Logical to Visual algorithm (e.g. one used in MS Windows), or perform a
767 * Logical to Logical transformation.</p>
768 *
769 * <ul>
770 * <li>When the reordering mode is set to <code>#UBIDI_REORDER_DEFAULT</code>,
771 * the standard Bidi Logical to Visual algorithm is applied.</li>
772 *
773 * <li>When the reordering mode is set to
774 * <code>#UBIDI_REORDER_NUMBERS_SPECIAL</code>,
775 * the algorithm used to perform Bidi transformations when calling
776 * <code>ubidi_setPara</code> should approximate the algorithm used in
777 * Microsoft Windows XP rather than strictly conform to the Unicode Bidi
778 * algorithm.
779 * <br>
780 * The differences between the basic algorithm and the algorithm addressed
781 * by this option are as follows:
782 * <ul>
783 * <li>Within text at an even embedding level, the sequence "123AB"
784 * (where AB represent R or AL letters) is transformed to "123BA" by the
785 * Unicode algorithm and to "BA123" by the Windows algorithm.</li>
786 * <li>Arabic-Indic numbers (AN) are handled by the Windows algorithm just
787 * like regular numbers (EN).</li>
788 * </ul></li>
789 *
790 * <li>When the reordering mode is set to
791 * <code>#UBIDI_REORDER_GROUP_NUMBERS_WITH_R</code>,
792 * numbers located between LTR text and RTL text are associated with the RTL
793 * text. For instance, an LTR paragraph with content "abc 123 DEF" (where
794 * upper case letters represent RTL characters) will be transformed to
795 * "abc FED 123" (and not "abc 123 FED"), "DEF 123 abc" will be transformed
796 * to "123 FED abc" and "123 FED abc" will be transformed to "DEF 123 abc".
797 * This makes the algorithm reversible and makes it useful when round trip
798 * (from visual to logical and back to visual) must be achieved without
799 * adding LRM characters. However, this is a variation from the standard
800 * Unicode Bidi algorithm.<br>
801 * The source text should not contain Bidi control characters other than LRM
802 * or RLM.</li>
803 *
804 * <li>When the reordering mode is set to
805 * <code>#UBIDI_REORDER_RUNS_ONLY</code>,
806 * a "Logical to Logical" transformation must be performed:
807 * <ul>
808 * <li>If the default text level of the source text (argument <code>paraLevel</code>
809 * in <code>ubidi_setPara</code>) is even, the source text will be handled as
810 * LTR logical text and will be transformed to the RTL logical text which has
811 * the same LTR visual display.</li>
812 * <li>If the default level of the source text is odd, the source text
813 * will be handled as RTL logical text and will be transformed to the
814 * LTR logical text which has the same LTR visual display.</li>
815 * </ul>
816 * This mode may be needed when logical text which is basically Arabic or
817 * Hebrew, with possible included numbers or phrases in English, has to be
818 * displayed as if it had an even embedding level (this can happen if the
819 * displaying application treats all text as if it was basically LTR).
820 * <br>
821 * This mode may also be needed in the reverse case, when logical text which is
822 * basically English, with possible included phrases in Arabic or Hebrew, has to
823 * be displayed as if it had an odd embedding level.
824 * <br>
825 * Both cases could be handled by adding LRE or RLE at the head of the text,
826 * if the display subsystem supports these formatting controls. If it does not,
827 * the problem may be handled by transforming the source text in this mode
828 * before displaying it, so that it will be displayed properly.<br>
829 * The source text should not contain Bidi control characters other than LRM
830 * or RLM.</li>
831 *
832 * <li>When the reordering mode is set to
833 * <code>#UBIDI_REORDER_INVERSE_NUMBERS_AS_L</code>, an "inverse Bidi" algorithm
834 * is applied.
835 * Runs of text with numeric characters will be treated like LTR letters and
836 * may need to be surrounded with LRM characters when they are written in
837 * reordered sequence (the option <code>#UBIDI_INSERT_LRM_FOR_NUMERIC</code> can
838 * be used with function <code>ubidi_writeReordered</code> to this end. This
839 * mode is equivalent to calling <code>ubidi_setInverse()</code> with
840 * argument <code>isInverse</code> set to <code>true</code>.</li>
841 *
842 * <li>When the reordering mode is set to
843 * <code>#UBIDI_REORDER_INVERSE_LIKE_DIRECT</code>, the "direct" Logical to Visual
844 * Bidi algorithm is used as an approximation of an "inverse Bidi" algorithm.
845 * This mode is similar to mode <code>#UBIDI_REORDER_INVERSE_NUMBERS_AS_L</code>
846 * but is closer to the regular Bidi algorithm.
847 * <br>
848 * For example, an LTR paragraph with the content "FED 123 456 CBA" (where
849 * upper case represents RTL characters) will be transformed to
850 * "ABC 456 123 DEF", as opposed to "DEF 123 456 ABC"
851 * with mode <code>UBIDI_REORDER_INVERSE_NUMBERS_AS_L</code>.<br>
852 * When used in conjunction with option
853 * <code>#UBIDI_OPTION_INSERT_MARKS</code>, this mode generally
854 * adds Bidi marks to the output significantly more sparingly than mode
855 * <code>#UBIDI_REORDER_INVERSE_NUMBERS_AS_L</code> with option
856 * <code>#UBIDI_INSERT_LRM_FOR_NUMERIC</code> in calls to
857 * <code>ubidi_writeReordered</code>.</li>
858 *
859 * <li>When the reordering mode is set to
860 * <code>#UBIDI_REORDER_INVERSE_FOR_NUMBERS_SPECIAL</code>, the Logical to Visual
861 * Bidi algorithm used in Windows XP is used as an approximation of an "inverse Bidi" algorithm.
862 * <br>
863 * For example, an LTR paragraph with the content "abc FED123" (where
864 * upper case represents RTL characters) will be transformed to "abc 123DEF."</li>
865 * </ul>
866 *
867 * <p>In all the reordering modes specifying an "inverse Bidi" algorithm
868 * (i.e. those with a name starting with <code>UBIDI_REORDER_INVERSE</code>),
869 * output runs should be retrieved using
870 * <code>ubidi_getVisualRun()</code>, and the output text with
871 * <code>ubidi_writeReordered()</code>. The caller should keep in mind that in
872 * "inverse Bidi" modes the input is actually visually ordered text and
873 * reordered output returned by <code>ubidi_getVisualRun()</code> or
874 * <code>ubidi_writeReordered()</code> are actually runs or character string
875 * of logically ordered output.<br>
876 * For all the "inverse Bidi" modes, the source text should not contain
877 * Bidi control characters other than LRM or RLM.</p>
878 *
879 * <p>Note that option <code>#UBIDI_OUTPUT_REVERSE</code> of
880 * <code>ubidi_writeReordered</code> has no useful meaning and should not be
881 * used in conjunction with any value of the reordering mode specifying
882 * "inverse Bidi" or with value <code>UBIDI_REORDER_RUNS_ONLY</code>.
883 *
884 * @param pBiDi is a <code>UBiDi</code> object.
885 * @param reorderingMode specifies the required variant of the Bidi algorithm.
886 *
887 * @see UBiDiReorderingMode
888 * @see ubidi_setInverse
889 * @see ubidi_setPara
890 * @see ubidi_writeReordered
891 * @stable ICU 3.6
892 */
893U_CAPI void U_EXPORT2
894ubidi_setReorderingMode(UBiDi *pBiDi, UBiDiReorderingMode reorderingMode);
895
896/**
897 * What is the requested reordering mode for a given Bidi object?
898 *
899 * @param pBiDi is a <code>UBiDi</code> object.
900 * @return the current reordering mode of the Bidi object
901 * @see ubidi_setReorderingMode
902 * @stable ICU 3.6
903 */
904U_CAPI UBiDiReorderingMode U_EXPORT2
905ubidi_getReorderingMode(UBiDi *pBiDi);
906
907/**
908 * <code>UBiDiReorderingOption</code> values indicate which options are
909 * specified to affect the Bidi algorithm.
910 *
911 * @see ubidi_setReorderingOptions
912 * @stable ICU 3.6
913 */
914typedef enum UBiDiReorderingOption {
915 /**
916 * option value for <code>ubidi_setReorderingOptions</code>:
917 * disable all the options which can be set with this function
918 * @see ubidi_setReorderingOptions
919 * @stable ICU 3.6
920 */
921 UBIDI_OPTION_DEFAULT = 0,
922
923 /**
924 * option bit for <code>ubidi_setReorderingOptions</code>:
925 * insert Bidi marks (LRM or RLM) when needed to ensure correct result of
926 * a reordering to a Logical order
927 *
928 * <p>This option must be set or reset before calling
929 * <code>ubidi_setPara</code>.</p>
930 *
931 * <p>This option is significant only with reordering modes which generate
932 * a result with Logical order, specifically:</p>
933 * <ul>
934 * <li><code>#UBIDI_REORDER_RUNS_ONLY</code></li>
935 * <li><code>#UBIDI_REORDER_INVERSE_NUMBERS_AS_L</code></li>
936 * <li><code>#UBIDI_REORDER_INVERSE_LIKE_DIRECT</code></li>
937 * <li><code>#UBIDI_REORDER_INVERSE_FOR_NUMBERS_SPECIAL</code></li>
938 * </ul>
939 *
940 * <p>If this option is set in conjunction with reordering mode
941 * <code>#UBIDI_REORDER_INVERSE_NUMBERS_AS_L</code> or with calling
942 * <code>ubidi_setInverse(true)</code>, it implies
943 * option <code>#UBIDI_INSERT_LRM_FOR_NUMERIC</code>
944 * in calls to function <code>ubidi_writeReordered()</code>.</p>
945 *
946 * <p>For other reordering modes, a minimum number of LRM or RLM characters
947 * will be added to the source text after reordering it so as to ensure
948 * round trip, i.e. when applying the inverse reordering mode on the
949 * resulting logical text with removal of Bidi marks
950 * (option <code>#UBIDI_OPTION_REMOVE_CONTROLS</code> set before calling
951 * <code>ubidi_setPara()</code> or option <code>#UBIDI_REMOVE_BIDI_CONTROLS</code>
952 * in <code>ubidi_writeReordered</code>), the result will be identical to the
953 * source text in the first transformation.
954 *
955 * <p>This option will be ignored if specified together with option
956 * <code>#UBIDI_OPTION_REMOVE_CONTROLS</code>. It inhibits option
957 * <code>UBIDI_REMOVE_BIDI_CONTROLS</code> in calls to function
958 * <code>ubidi_writeReordered()</code> and it implies option
959 * <code>#UBIDI_INSERT_LRM_FOR_NUMERIC</code> in calls to function
960 * <code>ubidi_writeReordered()</code> if the reordering mode is
961 * <code>#UBIDI_REORDER_INVERSE_NUMBERS_AS_L</code>.</p>
962 *
963 * @see ubidi_setReorderingMode
964 * @see ubidi_setReorderingOptions
965 * @stable ICU 3.6
966 */
967 UBIDI_OPTION_INSERT_MARKS = 1,
968
969 /**
970 * option bit for <code>ubidi_setReorderingOptions</code>:
971 * remove Bidi control characters
972 *
973 * <p>This option must be set or reset before calling
974 * <code>ubidi_setPara</code>.</p>
975 *
976 * <p>This option nullifies option <code>#UBIDI_OPTION_INSERT_MARKS</code>.
977 * It inhibits option <code>#UBIDI_INSERT_LRM_FOR_NUMERIC</code> in calls
978 * to function <code>ubidi_writeReordered()</code> and it implies option
979 * <code>#UBIDI_REMOVE_BIDI_CONTROLS</code> in calls to that function.</p>
980 *
981 * @see ubidi_setReorderingMode
982 * @see ubidi_setReorderingOptions
983 * @stable ICU 3.6
984 */
985 UBIDI_OPTION_REMOVE_CONTROLS = 2,
986
987 /**
988 * option bit for <code>ubidi_setReorderingOptions</code>:
989 * process the output as part of a stream to be continued
990 *
991 * <p>This option must be set or reset before calling
992 * <code>ubidi_setPara</code>.</p>
993 *
994 * <p>This option specifies that the caller is interested in processing large
995 * text object in parts.
996 * The results of the successive calls are expected to be concatenated by the
997 * caller. Only the call for the last part will have this option bit off.</p>
998 *
999 * <p>When this option bit is on, <code>ubidi_setPara()</code> may process
1000 * less than the full source text in order to truncate the text at a meaningful
1001 * boundary. The caller should call <code>ubidi_getProcessedLength()</code>
1002 * immediately after calling <code>ubidi_setPara()</code> in order to
1003 * determine how much of the source text has been processed.
1004 * Source text beyond that length should be resubmitted in following calls to
1005 * <code>ubidi_setPara</code>. The processed length may be less than
1006 * the length of the source text if a character preceding the last character of
1007 * the source text constitutes a reasonable boundary (like a block separator)
1008 * for text to be continued.<br>
1009 * If the last character of the source text constitutes a reasonable
1010 * boundary, the whole text will be processed at once.<br>
1011 * If nowhere in the source text there exists
1012 * such a reasonable boundary, the processed length will be zero.<br>
1013 * The caller should check for such an occurrence and do one of the following:
1014 * <ul><li>submit a larger amount of text with a better chance to include
1015 * a reasonable boundary.</li>
1016 * <li>resubmit the same text after turning off option
1017 * <code>UBIDI_OPTION_STREAMING</code>.</li></ul>
1018 * In all cases, this option should be turned off before processing the last
1019 * part of the text.</p>
1020 *
1021 * <p>When the <code>UBIDI_OPTION_STREAMING</code> option is used,
1022 * it is recommended to call <code>ubidi_orderParagraphsLTR()</code> with
1023 * argument <code>orderParagraphsLTR</code> set to <code>true</code> before
1024 * calling <code>ubidi_setPara</code> so that later paragraphs may be
1025 * concatenated to previous paragraphs on the right.</p>
1026 *
1027 * @see ubidi_setReorderingMode
1028 * @see ubidi_setReorderingOptions
1029 * @see ubidi_getProcessedLength
1030 * @see ubidi_orderParagraphsLTR
1031 * @stable ICU 3.6
1032 */
1033 UBIDI_OPTION_STREAMING = 4
1034} UBiDiReorderingOption;
1035
1036/**
1037 * Specify which of the reordering options
1038 * should be applied during Bidi transformations.
1039 *
1040 * @param pBiDi is a <code>UBiDi</code> object.
1041 * @param reorderingOptions is a combination of zero or more of the following
1042 * options:
1043 * <code>#UBIDI_OPTION_DEFAULT</code>, <code>#UBIDI_OPTION_INSERT_MARKS</code>,
1044 * <code>#UBIDI_OPTION_REMOVE_CONTROLS</code>, <code>#UBIDI_OPTION_STREAMING</code>.
1045 *
1046 * @see ubidi_getReorderingOptions
1047 * @stable ICU 3.6
1048 */
1049U_CAPI void U_EXPORT2
1050ubidi_setReorderingOptions(UBiDi *pBiDi, uint32_t reorderingOptions);
1051
1052/**
1053 * What are the reordering options applied to a given Bidi object?
1054 *
1055 * @param pBiDi is a <code>UBiDi</code> object.
1056 * @return the current reordering options of the Bidi object
1057 * @see ubidi_setReorderingOptions
1058 * @stable ICU 3.6
1059 */
1060U_CAPI uint32_t U_EXPORT2
1061ubidi_getReorderingOptions(UBiDi *pBiDi);
1062
1063/**
1064 * Set the context before a call to ubidi_setPara().<p>
1065 *
1066 * ubidi_setPara() computes the left-right directionality for a given piece
1067 * of text which is supplied as one of its arguments. Sometimes this piece
1068 * of text (the "main text") should be considered in context, because text
1069 * appearing before ("prologue") and/or after ("epilogue") the main text
1070 * may affect the result of this computation.<p>
1071 *
1072 * This function specifies the prologue and/or the epilogue for the next
1073 * call to ubidi_setPara(). The characters specified as prologue and
1074 * epilogue should not be modified by the calling program until the call
1075 * to ubidi_setPara() has returned. If successive calls to ubidi_setPara()
1076 * all need specification of a context, ubidi_setContext() must be called
1077 * before each call to ubidi_setPara(). In other words, a context is not
1078 * "remembered" after the following successful call to ubidi_setPara().<p>
1079 *
1080 * If a call to ubidi_setPara() specifies UBIDI_DEFAULT_LTR or
1081 * UBIDI_DEFAULT_RTL as paraLevel and is preceded by a call to
1082 * ubidi_setContext() which specifies a prologue, the paragraph level will
1083 * be computed taking in consideration the text in the prologue.<p>
1084 *
1085 * When ubidi_setPara() is called without a previous call to
1086 * ubidi_setContext, the main text is handled as if preceded and followed
1087 * by strong directional characters at the current paragraph level.
1088 * Calling ubidi_setContext() with specification of a prologue will change
1089 * this behavior by handling the main text as if preceded by the last
1090 * strong character appearing in the prologue, if any.
1091 * Calling ubidi_setContext() with specification of an epilogue will change
1092 * the behavior of ubidi_setPara() by handling the main text as if followed
1093 * by the first strong character or digit appearing in the epilogue, if any.<p>
1094 *
1095 * Note 1: if <code>ubidi_setContext</code> is called repeatedly without
1096 * calling <code>ubidi_setPara</code>, the earlier calls have no effect,
1097 * only the last call will be remembered for the next call to
1098 * <code>ubidi_setPara</code>.<p>
1099 *
1100 * Note 2: calling <code>ubidi_setContext(pBiDi, NULL, 0, NULL, 0, &errorCode)</code>
1101 * cancels any previous setting of non-empty prologue or epilogue.
1102 * The next call to <code>ubidi_setPara()</code> will process no
1103 * prologue or epilogue.<p>
1104 *
1105 * Note 3: users must be aware that even after setting the context
1106 * before a call to ubidi_setPara() to perform e.g. a logical to visual
1107 * transformation, the resulting string may not be identical to what it
1108 * would have been if all the text, including prologue and epilogue, had
1109 * been processed together.<br>
1110 * Example (upper case letters represent RTL characters):<br>
1111 * &nbsp;&nbsp;prologue = "<code>abc DE</code>"<br>
1112 * &nbsp;&nbsp;epilogue = none<br>
1113 * &nbsp;&nbsp;main text = "<code>FGH xyz</code>"<br>
1114 * &nbsp;&nbsp;paraLevel = UBIDI_LTR<br>
1115 * &nbsp;&nbsp;display without prologue = "<code>HGF xyz</code>"
1116 * ("HGF" is adjacent to "xyz")<br>
1117 * &nbsp;&nbsp;display with prologue = "<code>abc HGFED xyz</code>"
1118 * ("HGF" is not adjacent to "xyz")<br>
1119 *
1120 * @param pBiDi is a paragraph <code>UBiDi</code> object.
1121 *
1122 * @param prologue is a pointer to the text which precedes the text that
1123 * will be specified in a coming call to ubidi_setPara().
1124 * If there is no prologue to consider, then <code>proLength</code>
1125 * must be zero and this pointer can be NULL.
1126 *
1127 * @param proLength is the length of the prologue; if <code>proLength==-1</code>
1128 * then the prologue must be zero-terminated.
1129 * Otherwise proLength must be >= 0. If <code>proLength==0</code>, it means
1130 * that there is no prologue to consider.
1131 *
1132 * @param epilogue is a pointer to the text which follows the text that
1133 * will be specified in a coming call to ubidi_setPara().
1134 * If there is no epilogue to consider, then <code>epiLength</code>
1135 * must be zero and this pointer can be NULL.
1136 *
1137 * @param epiLength is the length of the epilogue; if <code>epiLength==-1</code>
1138 * then the epilogue must be zero-terminated.
1139 * Otherwise epiLength must be >= 0. If <code>epiLength==0</code>, it means
1140 * that there is no epilogue to consider.
1141 *
1142 * @param pErrorCode must be a valid pointer to an error code value.
1143 *
1144 * @see ubidi_setPara
1145 * @stable ICU 4.8
1146 */
1147U_CAPI void U_EXPORT2
1148ubidi_setContext(UBiDi *pBiDi,
1149 const UChar *prologue, int32_t proLength,
1150 const UChar *epilogue, int32_t epiLength,
1151 UErrorCode *pErrorCode);
1152
1153/**
1154 * Perform the Unicode Bidi algorithm. It is defined in the
1155 * <a href="http://www.unicode.org/unicode/reports/tr9/">Unicode Standard Annex #9</a>,
1156 * version 13,
1157 * also described in The Unicode Standard, Version 4.0 .<p>
1158 *
1159 * This function takes a piece of plain text containing one or more paragraphs,
1160 * with or without externally specified embedding levels from <i>styled</i>
1161 * text and computes the left-right-directionality of each character.<p>
1162 *
1163 * If the entire text is all of the same directionality, then
1164 * the function may not perform all the steps described by the algorithm,
1165 * i.e., some levels may not be the same as if all steps were performed.
1166 * This is not relevant for unidirectional text.<br>
1167 * For example, in pure LTR text with numbers the numbers would get
1168 * a resolved level of 2 higher than the surrounding text according to
1169 * the algorithm. This implementation may set all resolved levels to
1170 * the same value in such a case.<p>
1171 *
1172 * The text can be composed of multiple paragraphs. Occurrence of a block
1173 * separator in the text terminates a paragraph, and whatever comes next starts
1174 * a new paragraph. The exception to this rule is when a Carriage Return (CR)
1175 * is followed by a Line Feed (LF). Both CR and LF are block separators, but
1176 * in that case, the pair of characters is considered as terminating the
1177 * preceding paragraph, and a new paragraph will be started by a character
1178 * coming after the LF.
1179 *
1180 * @param pBiDi A <code>UBiDi</code> object allocated with <code>ubidi_open()</code>
1181 * which will be set to contain the reordering information,
1182 * especially the resolved levels for all the characters in <code>text</code>.
1183 *
1184 * @param text is a pointer to the text that the Bidi algorithm will be performed on.
1185 * This pointer is stored in the UBiDi object and can be retrieved
1186 * with <code>ubidi_getText()</code>.<br>
1187 * <strong>Note:</strong> the text must be (at least) <code>length</code> long.
1188 *
1189 * @param length is the length of the text; if <code>length==-1</code> then
1190 * the text must be zero-terminated.
1191 *
1192 * @param paraLevel specifies the default level for the text;
1193 * it is typically 0 (LTR) or 1 (RTL).
1194 * If the function shall determine the paragraph level from the text,
1195 * then <code>paraLevel</code> can be set to
1196 * either <code>#UBIDI_DEFAULT_LTR</code>
1197 * or <code>#UBIDI_DEFAULT_RTL</code>; if the text contains multiple
1198 * paragraphs, the paragraph level shall be determined separately for
1199 * each paragraph; if a paragraph does not include any strongly typed
1200 * character, then the desired default is used (0 for LTR or 1 for RTL).
1201 * Any other value between 0 and <code>#UBIDI_MAX_EXPLICIT_LEVEL</code>
1202 * is also valid, with odd levels indicating RTL.
1203 *
1204 * @param embeddingLevels (in) may be used to preset the embedding and override levels,
1205 * ignoring characters like LRE and PDF in the text.
1206 * A level overrides the directional property of its corresponding
1207 * (same index) character if the level has the
1208 * <code>#UBIDI_LEVEL_OVERRIDE</code> bit set.<br><br>
1209 * Aside from that bit, it must be
1210 * <code>paraLevel<=embeddingLevels[]<=UBIDI_MAX_EXPLICIT_LEVEL</code>,
1211 * except that level 0 is always allowed.
1212 * Level 0 for a paragraph separator prevents reordering of paragraphs;
1213 * this only works reliably if <code>#UBIDI_LEVEL_OVERRIDE</code>
1214 * is also set for paragraph separators.
1215 * Level 0 for other characters is treated as a wildcard
1216 * and is lifted up to the resolved level of the surrounding paragraph.<br><br>
1217 * <strong>Caution: </strong>A copy of this pointer, not of the levels,
1218 * will be stored in the <code>UBiDi</code> object;
1219 * the <code>embeddingLevels</code> array must not be
1220 * deallocated before the <code>UBiDi</code> structure is destroyed or reused,
1221 * and the <code>embeddingLevels</code>
1222 * should not be modified to avoid unexpected results on subsequent Bidi operations.
1223 * However, the <code>ubidi_setPara()</code> and
1224 * <code>ubidi_setLine()</code> functions may modify some or all of the levels.<br><br>
1225 * After the <code>UBiDi</code> object is reused or destroyed, the caller
1226 * must take care of the deallocation of the <code>embeddingLevels</code> array.<br><br>
1227 * <strong>Note:</strong> the <code>embeddingLevels</code> array must be
1228 * at least <code>length</code> long.
1229 * This pointer can be <code>NULL</code> if this
1230 * value is not necessary.
1231 *
1232 * @param pErrorCode must be a valid pointer to an error code value.
1233 * @stable ICU 2.0
1234 */
1235U_CAPI void U_EXPORT2
1236ubidi_setPara(UBiDi *pBiDi, const UChar *text, int32_t length,
1237 UBiDiLevel paraLevel, UBiDiLevel *embeddingLevels,
1238 UErrorCode *pErrorCode);
1239
1240/**
1241 * <code>ubidi_setLine()</code> sets a <code>UBiDi</code> to
1242 * contain the reordering information, especially the resolved levels,
1243 * for all the characters in a line of text. This line of text is
1244 * specified by referring to a <code>UBiDi</code> object representing
1245 * this information for a piece of text containing one or more paragraphs,
1246 * and by specifying a range of indexes in this text.<p>
1247 * In the new line object, the indexes will range from 0 to <code>limit-start-1</code>.<p>
1248 *
1249 * This is used after calling <code>ubidi_setPara()</code>
1250 * for a piece of text, and after line-breaking on that text.
1251 * It is not necessary if each paragraph is treated as a single line.<p>
1252 *
1253 * After line-breaking, rules (L1) and (L2) for the treatment of
1254 * trailing WS and for reordering are performed on
1255 * a <code>UBiDi</code> object that represents a line.<p>
1256 *
1257 * <strong>Important: </strong><code>pLineBiDi</code> shares data with
1258 * <code>pParaBiDi</code>.
1259 * You must destroy or reuse <code>pLineBiDi</code> before <code>pParaBiDi</code>.
1260 * In other words, you must destroy or reuse the <code>UBiDi</code> object for a line
1261 * before the object for its parent paragraph.<p>
1262 *
1263 * The text pointer that was stored in <code>pParaBiDi</code> is also copied,
1264 * and <code>start</code> is added to it so that it points to the beginning of the
1265 * line for this object.
1266 *
1267 * @param pParaBiDi is the parent paragraph object. It must have been set
1268 * by a successful call to ubidi_setPara.
1269 *
1270 * @param start is the line's first index into the text.
1271 *
1272 * @param limit is just behind the line's last index into the text
1273 * (its last index +1).<br>
1274 * It must be <code>0<=start<limit<=</code>containing paragraph limit.
1275 * If the specified line crosses a paragraph boundary, the function
1276 * will terminate with error code U_ILLEGAL_ARGUMENT_ERROR.
1277 *
1278 * @param pLineBiDi is the object that will now represent a line of the text.
1279 *
1280 * @param pErrorCode must be a valid pointer to an error code value.
1281 *
1282 * @see ubidi_setPara
1283 * @see ubidi_getProcessedLength
1284 * @stable ICU 2.0
1285 */
1286U_CAPI void U_EXPORT2
1287ubidi_setLine(const UBiDi *pParaBiDi,
1288 int32_t start, int32_t limit,
1289 UBiDi *pLineBiDi,
1290 UErrorCode *pErrorCode);
1291
1292/**
1293 * Get the directionality of the text.
1294 *
1295 * @param pBiDi is the paragraph or line <code>UBiDi</code> object.
1296 *
1297 * @return a value of <code>UBIDI_LTR</code>, <code>UBIDI_RTL</code>
1298 * or <code>UBIDI_MIXED</code>
1299 * that indicates if the entire text
1300 * represented by this object is unidirectional,
1301 * and which direction, or if it is mixed-directional.
1302 * Note - The value <code>UBIDI_NEUTRAL</code> is never returned from this method.
1303 *
1304 * @see UBiDiDirection
1305 * @stable ICU 2.0
1306 */
1307U_CAPI UBiDiDirection U_EXPORT2
1308ubidi_getDirection(const UBiDi *pBiDi);
1309
1310/**
1311 * Gets the base direction of the text provided according
1312 * to the Unicode Bidirectional Algorithm. The base direction
1313 * is derived from the first character in the string with bidirectional
1314 * character type L, R, or AL. If the first such character has type L,
1315 * <code>UBIDI_LTR</code> is returned. If the first such character has
1316 * type R or AL, <code>UBIDI_RTL</code> is returned. If the string does
1317 * not contain any character of these types, then
1318 * <code>UBIDI_NEUTRAL</code> is returned.
1319 *
1320 * This is a lightweight function for use when only the base direction
1321 * is needed and no further bidi processing of the text is needed.
1322 *
1323 * @param text is a pointer to the text whose base
1324 * direction is needed.
1325 * Note: the text must be (at least) @c length long.
1326 *
1327 * @param length is the length of the text;
1328 * if <code>length==-1</code> then the text
1329 * must be zero-terminated.
1330 *
1331 * @return <code>UBIDI_LTR</code>, <code>UBIDI_RTL</code>,
1332 * <code>UBIDI_NEUTRAL</code>
1333 *
1334 * @see UBiDiDirection
1335 * @stable ICU 4.6
1336 */
1337U_CAPI UBiDiDirection U_EXPORT2
1338ubidi_getBaseDirection(const UChar *text, int32_t length );
1339
1340/**
1341 * Get the pointer to the text.
1342 *
1343 * @param pBiDi is the paragraph or line <code>UBiDi</code> object.
1344 *
1345 * @return The pointer to the text that the UBiDi object was created for.
1346 *
1347 * @see ubidi_setPara
1348 * @see ubidi_setLine
1349 * @stable ICU 2.0
1350 */
1351U_CAPI const UChar * U_EXPORT2
1352ubidi_getText(const UBiDi *pBiDi);
1353
1354/**
1355 * Get the length of the text.
1356 *
1357 * @param pBiDi is the paragraph or line <code>UBiDi</code> object.
1358 *
1359 * @return The length of the text that the UBiDi object was created for.
1360 * @stable ICU 2.0
1361 */
1362U_CAPI int32_t U_EXPORT2
1363ubidi_getLength(const UBiDi *pBiDi);
1364
1365/**
1366 * Get the paragraph level of the text.
1367 *
1368 * @param pBiDi is the paragraph or line <code>UBiDi</code> object.
1369 *
1370 * @return The paragraph level. If there are multiple paragraphs, their
1371 * level may vary if the required paraLevel is UBIDI_DEFAULT_LTR or
1372 * UBIDI_DEFAULT_RTL. In that case, the level of the first paragraph
1373 * is returned.
1374 *
1375 * @see UBiDiLevel
1376 * @see ubidi_getParagraph
1377 * @see ubidi_getParagraphByIndex
1378 * @stable ICU 2.0
1379 */
1380U_CAPI UBiDiLevel U_EXPORT2
1381ubidi_getParaLevel(const UBiDi *pBiDi);
1382
1383/**
1384 * Get the number of paragraphs.
1385 *
1386 * @param pBiDi is the paragraph or line <code>UBiDi</code> object.
1387 *
1388 * @return The number of paragraphs.
1389 * @stable ICU 3.4
1390 */
1391U_CAPI int32_t U_EXPORT2
1392ubidi_countParagraphs(UBiDi *pBiDi);
1393
1394/**
1395 * Get a paragraph, given a position within the text.
1396 * This function returns information about a paragraph.<br>
1397 * Note: if the paragraph index is known, it is more efficient to
1398 * retrieve the paragraph information using ubidi_getParagraphByIndex().<p>
1399 *
1400 * @param pBiDi is the paragraph or line <code>UBiDi</code> object.
1401 *
1402 * @param charIndex is the index of a character within the text, in the
1403 * range <code>[0..ubidi_getProcessedLength(pBiDi)-1]</code>.
1404 *
1405 * @param pParaStart will receive the index of the first character of the
1406 * paragraph in the text.
1407 * This pointer can be <code>NULL</code> if this
1408 * value is not necessary.
1409 *
1410 * @param pParaLimit will receive the limit of the paragraph.
1411 * The l-value that you point to here may be the
1412 * same expression (variable) as the one for
1413 * <code>charIndex</code>.
1414 * This pointer can be <code>NULL</code> if this
1415 * value is not necessary.
1416 *
1417 * @param pParaLevel will receive the level of the paragraph.
1418 * This pointer can be <code>NULL</code> if this
1419 * value is not necessary.
1420 *
1421 * @param pErrorCode must be a valid pointer to an error code value.
1422 *
1423 * @return The index of the paragraph containing the specified position.
1424 *
1425 * @see ubidi_getProcessedLength
1426 * @stable ICU 3.4
1427 */
1428U_CAPI int32_t U_EXPORT2
1429ubidi_getParagraph(const UBiDi *pBiDi, int32_t charIndex, int32_t *pParaStart,
1430 int32_t *pParaLimit, UBiDiLevel *pParaLevel,
1431 UErrorCode *pErrorCode);
1432
1433/**
1434 * Get a paragraph, given the index of this paragraph.
1435 *
1436 * This function returns information about a paragraph.<p>
1437 *
1438 * @param pBiDi is the paragraph <code>UBiDi</code> object.
1439 *
1440 * @param paraIndex is the number of the paragraph, in the
1441 * range <code>[0..ubidi_countParagraphs(pBiDi)-1]</code>.
1442 *
1443 * @param pParaStart will receive the index of the first character of the
1444 * paragraph in the text.
1445 * This pointer can be <code>NULL</code> if this
1446 * value is not necessary.
1447 *
1448 * @param pParaLimit will receive the limit of the paragraph.
1449 * This pointer can be <code>NULL</code> if this
1450 * value is not necessary.
1451 *
1452 * @param pParaLevel will receive the level of the paragraph.
1453 * This pointer can be <code>NULL</code> if this
1454 * value is not necessary.
1455 *
1456 * @param pErrorCode must be a valid pointer to an error code value.
1457 *
1458 * @stable ICU 3.4
1459 */
1460U_CAPI void U_EXPORT2
1461ubidi_getParagraphByIndex(const UBiDi *pBiDi, int32_t paraIndex,
1462 int32_t *pParaStart, int32_t *pParaLimit,
1463 UBiDiLevel *pParaLevel, UErrorCode *pErrorCode);
1464
1465/**
1466 * Get the level for one character.
1467 *
1468 * @param pBiDi is the paragraph or line <code>UBiDi</code> object.
1469 *
1470 * @param charIndex the index of a character. It must be in the range
1471 * [0..ubidi_getProcessedLength(pBiDi)].
1472 *
1473 * @return The level for the character at charIndex (0 if charIndex is not
1474 * in the valid range).
1475 *
1476 * @see UBiDiLevel
1477 * @see ubidi_getProcessedLength
1478 * @stable ICU 2.0
1479 */
1480U_CAPI UBiDiLevel U_EXPORT2
1481ubidi_getLevelAt(const UBiDi *pBiDi, int32_t charIndex);
1482
1483/**
1484 * Get an array of levels for each character.<p>
1485 *
1486 * Note that this function may allocate memory under some
1487 * circumstances, unlike <code>ubidi_getLevelAt()</code>.
1488 *
1489 * @param pBiDi is the paragraph or line <code>UBiDi</code> object, whose
1490 * text length must be strictly positive.
1491 *
1492 * @param pErrorCode must be a valid pointer to an error code value.
1493 *
1494 * @return The levels array for the text,
1495 * or <code>NULL</code> if an error occurs.
1496 *
1497 * @see UBiDiLevel
1498 * @see ubidi_getProcessedLength
1499 * @stable ICU 2.0
1500 */
1501U_CAPI const UBiDiLevel * U_EXPORT2
1502ubidi_getLevels(UBiDi *pBiDi, UErrorCode *pErrorCode);
1503
1504/**
1505 * Get a logical run.
1506 * This function returns information about a run and is used
1507 * to retrieve runs in logical order.<p>
1508 * This is especially useful for line-breaking on a paragraph.
1509 *
1510 * @param pBiDi is the paragraph or line <code>UBiDi</code> object.
1511 *
1512 * @param logicalPosition is a logical position within the source text.
1513 *
1514 * @param pLogicalLimit will receive the limit of the corresponding run.
1515 * The l-value that you point to here may be the
1516 * same expression (variable) as the one for
1517 * <code>logicalPosition</code>.
1518 * This pointer can be <code>NULL</code> if this
1519 * value is not necessary.
1520 *
1521 * @param pLevel will receive the level of the corresponding run.
1522 * This pointer can be <code>NULL</code> if this
1523 * value is not necessary.
1524 *
1525 * @see ubidi_getProcessedLength
1526 * @stable ICU 2.0
1527 */
1528U_CAPI void U_EXPORT2
1529ubidi_getLogicalRun(const UBiDi *pBiDi, int32_t logicalPosition,
1530 int32_t *pLogicalLimit, UBiDiLevel *pLevel);
1531
1532/**
1533 * Get the number of runs.
1534 * This function may invoke the actual reordering on the
1535 * <code>UBiDi</code> object, after <code>ubidi_setPara()</code>
1536 * may have resolved only the levels of the text. Therefore,
1537 * <code>ubidi_countRuns()</code> may have to allocate memory,
1538 * and may fail doing so.
1539 *
1540 * @param pBiDi is the paragraph or line <code>UBiDi</code> object.
1541 *
1542 * @param pErrorCode must be a valid pointer to an error code value.
1543 *
1544 * @return The number of runs.
1545 * @stable ICU 2.0
1546 */
1547U_CAPI int32_t U_EXPORT2
1548ubidi_countRuns(UBiDi *pBiDi, UErrorCode *pErrorCode);
1549
1550/**
1551 * Get one run's logical start, length, and directionality,
1552 * which can be 0 for LTR or 1 for RTL.
1553 * In an RTL run, the character at the logical start is
1554 * visually on the right of the displayed run.
1555 * The length is the number of characters in the run.<p>
1556 * <code>ubidi_countRuns()</code> should be called
1557 * before the runs are retrieved.
1558 *
1559 * @param pBiDi is the paragraph or line <code>UBiDi</code> object.
1560 *
1561 * @param runIndex is the number of the run in visual order, in the
1562 * range <code>[0..ubidi_countRuns(pBiDi)-1]</code>.
1563 *
1564 * @param pLogicalStart is the first logical character index in the text.
1565 * The pointer may be <code>NULL</code> if this index is not needed.
1566 *
1567 * @param pLength is the number of characters (at least one) in the run.
1568 * The pointer may be <code>NULL</code> if this is not needed.
1569 *
1570 * @return the directionality of the run,
1571 * <code>UBIDI_LTR==0</code> or <code>UBIDI_RTL==1</code>,
1572 * never <code>UBIDI_MIXED</code>,
1573 * never <code>UBIDI_NEUTRAL</code>.
1574 *
1575 * @see ubidi_countRuns
1576 *
1577 * Example:
1578 * <pre>
1579 * \code
1580 * int32_t i, count=ubidi_countRuns(pBiDi),
1581 * logicalStart, visualIndex=0, length;
1582 * for(i=0; i<count; ++i) {
1583 * if(UBIDI_LTR==ubidi_getVisualRun(pBiDi, i, &logicalStart, &length)) {
1584 * do { // LTR
1585 * show_char(text[logicalStart++], visualIndex++);
1586 * } while(--length>0);
1587 * } else {
1588 * logicalStart+=length; // logicalLimit
1589 * do { // RTL
1590 * show_char(text[--logicalStart], visualIndex++);
1591 * } while(--length>0);
1592 * }
1593 * }
1594 *\endcode
1595 * </pre>
1596 *
1597 * Note that in right-to-left runs, code like this places
1598 * second surrogates before first ones (which is generally a bad idea)
1599 * and combining characters before base characters.
1600 * <p>
1601 * Use of <code>ubidi_writeReordered()</code>, optionally with the
1602 * <code>#UBIDI_KEEP_BASE_COMBINING</code> option, can be considered in order
1603 * to avoid these issues.
1604 * @stable ICU 2.0
1605 */
1606U_CAPI UBiDiDirection U_EXPORT2
1607ubidi_getVisualRun(UBiDi *pBiDi, int32_t runIndex,
1608 int32_t *pLogicalStart, int32_t *pLength);
1609
1610/**
1611 * Get the visual position from a logical text position.
1612 * If such a mapping is used many times on the same
1613 * <code>UBiDi</code> object, then calling
1614 * <code>ubidi_getLogicalMap()</code> is more efficient.<p>
1615 *
1616 * The value returned may be <code>#UBIDI_MAP_NOWHERE</code> if there is no
1617 * visual position because the corresponding text character is a Bidi control
1618 * removed from output by the option <code>#UBIDI_OPTION_REMOVE_CONTROLS</code>.
1619 * <p>
1620 * When the visual output is altered by using options of
1621 * <code>ubidi_writeReordered()</code> such as <code>UBIDI_INSERT_LRM_FOR_NUMERIC</code>,
1622 * <code>UBIDI_KEEP_BASE_COMBINING</code>, <code>UBIDI_OUTPUT_REVERSE</code>,
1623 * <code>UBIDI_REMOVE_BIDI_CONTROLS</code>, the visual position returned may not
1624 * be correct. It is advised to use, when possible, reordering options
1625 * such as <code>UBIDI_OPTION_INSERT_MARKS</code> and <code>UBIDI_OPTION_REMOVE_CONTROLS</code>.
1626 * <p>
1627 * Note that in right-to-left runs, this mapping places
1628 * second surrogates before first ones (which is generally a bad idea)
1629 * and combining characters before base characters.
1630 * Use of <code>ubidi_writeReordered()</code>, optionally with the
1631 * <code>#UBIDI_KEEP_BASE_COMBINING</code> option can be considered instead
1632 * of using the mapping, in order to avoid these issues.
1633 *
1634 * @param pBiDi is the paragraph or line <code>UBiDi</code> object.
1635 *
1636 * @param logicalIndex is the index of a character in the text.
1637 *
1638 * @param pErrorCode must be a valid pointer to an error code value.
1639 *
1640 * @return The visual position of this character.
1641 *
1642 * @see ubidi_getLogicalMap
1643 * @see ubidi_getLogicalIndex
1644 * @see ubidi_getProcessedLength
1645 * @stable ICU 2.0
1646 */
1647U_CAPI int32_t U_EXPORT2
1648ubidi_getVisualIndex(UBiDi *pBiDi, int32_t logicalIndex, UErrorCode *pErrorCode);
1649
1650/**
1651 * Get the logical text position from a visual position.
1652 * If such a mapping is used many times on the same
1653 * <code>UBiDi</code> object, then calling
1654 * <code>ubidi_getVisualMap()</code> is more efficient.<p>
1655 *
1656 * The value returned may be <code>#UBIDI_MAP_NOWHERE</code> if there is no
1657 * logical position because the corresponding text character is a Bidi mark
1658 * inserted in the output by option <code>#UBIDI_OPTION_INSERT_MARKS</code>.
1659 * <p>
1660 * This is the inverse function to <code>ubidi_getVisualIndex()</code>.
1661 * <p>
1662 * When the visual output is altered by using options of
1663 * <code>ubidi_writeReordered()</code> such as <code>UBIDI_INSERT_LRM_FOR_NUMERIC</code>,
1664 * <code>UBIDI_KEEP_BASE_COMBINING</code>, <code>UBIDI_OUTPUT_REVERSE</code>,
1665 * <code>UBIDI_REMOVE_BIDI_CONTROLS</code>, the logical position returned may not
1666 * be correct. It is advised to use, when possible, reordering options
1667 * such as <code>UBIDI_OPTION_INSERT_MARKS</code> and <code>UBIDI_OPTION_REMOVE_CONTROLS</code>.
1668 *
1669 * @param pBiDi is the paragraph or line <code>UBiDi</code> object.
1670 *
1671 * @param visualIndex is the visual position of a character.
1672 *
1673 * @param pErrorCode must be a valid pointer to an error code value.
1674 *
1675 * @return The index of this character in the text.
1676 *
1677 * @see ubidi_getVisualMap
1678 * @see ubidi_getVisualIndex
1679 * @see ubidi_getResultLength
1680 * @stable ICU 2.0
1681 */
1682U_CAPI int32_t U_EXPORT2
1683ubidi_getLogicalIndex(UBiDi *pBiDi, int32_t visualIndex, UErrorCode *pErrorCode);
1684
1685/**
1686 * Get a logical-to-visual index map (array) for the characters in the UBiDi
1687 * (paragraph or line) object.
1688 * <p>
1689 * Some values in the map may be <code>#UBIDI_MAP_NOWHERE</code> if the
1690 * corresponding text characters are Bidi controls removed from the visual
1691 * output by the option <code>#UBIDI_OPTION_REMOVE_CONTROLS</code>.
1692 * <p>
1693 * When the visual output is altered by using options of
1694 * <code>ubidi_writeReordered()</code> such as <code>UBIDI_INSERT_LRM_FOR_NUMERIC</code>,
1695 * <code>UBIDI_KEEP_BASE_COMBINING</code>, <code>UBIDI_OUTPUT_REVERSE</code>,
1696 * <code>UBIDI_REMOVE_BIDI_CONTROLS</code>, the visual positions returned may not
1697 * be correct. It is advised to use, when possible, reordering options
1698 * such as <code>UBIDI_OPTION_INSERT_MARKS</code> and <code>UBIDI_OPTION_REMOVE_CONTROLS</code>.
1699 * <p>
1700 * Note that in right-to-left runs, this mapping places
1701 * second surrogates before first ones (which is generally a bad idea)
1702 * and combining characters before base characters.
1703 * Use of <code>ubidi_writeReordered()</code>, optionally with the
1704 * <code>#UBIDI_KEEP_BASE_COMBINING</code> option can be considered instead
1705 * of using the mapping, in order to avoid these issues.
1706 *
1707 * @param pBiDi is the paragraph or line <code>UBiDi</code> object.
1708 *
1709 * @param indexMap is a pointer to an array of <code>ubidi_getProcessedLength()</code>
1710 * indexes which will reflect the reordering of the characters.
1711 * If option <code>#UBIDI_OPTION_INSERT_MARKS</code> is set, the number
1712 * of elements allocated in <code>indexMap</code> must be no less than
1713 * <code>ubidi_getResultLength()</code>.
1714 * The array does not need to be initialized.<br><br>
1715 * The index map will result in <code>indexMap[logicalIndex]==visualIndex</code>.
1716 *
1717 * @param pErrorCode must be a valid pointer to an error code value.
1718 *
1719 * @see ubidi_getVisualMap
1720 * @see ubidi_getVisualIndex
1721 * @see ubidi_getProcessedLength
1722 * @see ubidi_getResultLength
1723 * @stable ICU 2.0
1724 */
1725U_CAPI void U_EXPORT2
1726ubidi_getLogicalMap(UBiDi *pBiDi, int32_t *indexMap, UErrorCode *pErrorCode);
1727
1728/**
1729 * Get a visual-to-logical index map (array) for the characters in the UBiDi
1730 * (paragraph or line) object.
1731 * <p>
1732 * Some values in the map may be <code>#UBIDI_MAP_NOWHERE</code> if the
1733 * corresponding text characters are Bidi marks inserted in the visual output
1734 * by the option <code>#UBIDI_OPTION_INSERT_MARKS</code>.
1735 * <p>
1736 * When the visual output is altered by using options of
1737 * <code>ubidi_writeReordered()</code> such as <code>UBIDI_INSERT_LRM_FOR_NUMERIC</code>,
1738 * <code>UBIDI_KEEP_BASE_COMBINING</code>, <code>UBIDI_OUTPUT_REVERSE</code>,
1739 * <code>UBIDI_REMOVE_BIDI_CONTROLS</code>, the logical positions returned may not
1740 * be correct. It is advised to use, when possible, reordering options
1741 * such as <code>UBIDI_OPTION_INSERT_MARKS</code> and <code>UBIDI_OPTION_REMOVE_CONTROLS</code>.
1742 *
1743 * @param pBiDi is the paragraph or line <code>UBiDi</code> object.
1744 *
1745 * @param indexMap is a pointer to an array of <code>ubidi_getResultLength()</code>
1746 * indexes which will reflect the reordering of the characters.
1747 * If option <code>#UBIDI_OPTION_REMOVE_CONTROLS</code> is set, the number
1748 * of elements allocated in <code>indexMap</code> must be no less than
1749 * <code>ubidi_getProcessedLength()</code>.
1750 * The array does not need to be initialized.<br><br>
1751 * The index map will result in <code>indexMap[visualIndex]==logicalIndex</code>.
1752 *
1753 * @param pErrorCode must be a valid pointer to an error code value.
1754 *
1755 * @see ubidi_getLogicalMap
1756 * @see ubidi_getLogicalIndex
1757 * @see ubidi_getProcessedLength
1758 * @see ubidi_getResultLength
1759 * @stable ICU 2.0
1760 */
1761U_CAPI void U_EXPORT2
1762ubidi_getVisualMap(UBiDi *pBiDi, int32_t *indexMap, UErrorCode *pErrorCode);
1763
1764/**
1765 * This is a convenience function that does not use a UBiDi object.
1766 * It is intended to be used for when an application has determined the levels
1767 * of objects (character sequences) and just needs to have them reordered (L2).
1768 * This is equivalent to using <code>ubidi_getLogicalMap()</code> on a
1769 * <code>UBiDi</code> object.
1770 *
1771 * @param levels is an array with <code>length</code> levels that have been determined by
1772 * the application.
1773 *
1774 * @param length is the number of levels in the array, or, semantically,
1775 * the number of objects to be reordered.
1776 * It must be <code>length>0</code>.
1777 *
1778 * @param indexMap is a pointer to an array of <code>length</code>
1779 * indexes which will reflect the reordering of the characters.
1780 * The array does not need to be initialized.<p>
1781 * The index map will result in <code>indexMap[logicalIndex]==visualIndex</code>.
1782 * @stable ICU 2.0
1783 */
1784U_CAPI void U_EXPORT2
1785ubidi_reorderLogical(const UBiDiLevel *levels, int32_t length, int32_t *indexMap);
1786
1787/**
1788 * This is a convenience function that does not use a UBiDi object.
1789 * It is intended to be used for when an application has determined the levels
1790 * of objects (character sequences) and just needs to have them reordered (L2).
1791 * This is equivalent to using <code>ubidi_getVisualMap()</code> on a
1792 * <code>UBiDi</code> object.
1793 *
1794 * @param levels is an array with <code>length</code> levels that have been determined by
1795 * the application.
1796 *
1797 * @param length is the number of levels in the array, or, semantically,
1798 * the number of objects to be reordered.
1799 * It must be <code>length>0</code>.
1800 *
1801 * @param indexMap is a pointer to an array of <code>length</code>
1802 * indexes which will reflect the reordering of the characters.
1803 * The array does not need to be initialized.<p>
1804 * The index map will result in <code>indexMap[visualIndex]==logicalIndex</code>.
1805 * @stable ICU 2.0
1806 */
1807U_CAPI void U_EXPORT2
1808ubidi_reorderVisual(const UBiDiLevel *levels, int32_t length, int32_t *indexMap);
1809
1810/**
1811 * Invert an index map.
1812 * The index mapping of the first map is inverted and written to
1813 * the second one.
1814 *
1815 * @param srcMap is an array with <code>length</code> elements
1816 * which defines the original mapping from a source array containing
1817 * <code>length</code> elements to a destination array.
1818 * Some elements of the source array may have no mapping in the
1819 * destination array. In that case, their value will be
1820 * the special value <code>UBIDI_MAP_NOWHERE</code>.
1821 * All elements must be >=0 or equal to <code>UBIDI_MAP_NOWHERE</code>.
1822 * Some elements may have a value >= <code>length</code>, if the
1823 * destination array has more elements than the source array.
1824 * There must be no duplicate indexes (two or more elements with the
1825 * same value except <code>UBIDI_MAP_NOWHERE</code>).
1826 *
1827 * @param destMap is an array with a number of elements equal to 1 + the highest
1828 * value in <code>srcMap</code>.
1829 * <code>destMap</code> will be filled with the inverse mapping.
1830 * If element with index i in <code>srcMap</code> has a value k different
1831 * from <code>UBIDI_MAP_NOWHERE</code>, this means that element i of
1832 * the source array maps to element k in the destination array.
1833 * The inverse map will have value i in its k-th element.
1834 * For all elements of the destination array which do not map to
1835 * an element in the source array, the corresponding element in the
1836 * inverse map will have a value equal to <code>UBIDI_MAP_NOWHERE</code>.
1837 *
1838 * @param length is the length of each array.
1839 * @see UBIDI_MAP_NOWHERE
1840 * @stable ICU 2.0
1841 */
1842U_CAPI void U_EXPORT2
1843ubidi_invertMap(const int32_t *srcMap, int32_t *destMap, int32_t length);
1844
1845/** option flags for ubidi_writeReordered() */
1846
1847/**
1848 * option bit for ubidi_writeReordered():
1849 * keep combining characters after their base characters in RTL runs
1850 *
1851 * @see ubidi_writeReordered
1852 * @stable ICU 2.0
1853 */
1854#define UBIDI_KEEP_BASE_COMBINING 1
1855
1856/**
1857 * option bit for ubidi_writeReordered():
1858 * replace characters with the "mirrored" property in RTL runs
1859 * by their mirror-image mappings
1860 *
1861 * @see ubidi_writeReordered
1862 * @stable ICU 2.0
1863 */
1864#define UBIDI_DO_MIRRORING 2
1865
1866/**
1867 * option bit for ubidi_writeReordered():
1868 * surround the run with LRMs if necessary;
1869 * this is part of the approximate "inverse Bidi" algorithm
1870 *
1871 * <p>This option does not imply corresponding adjustment of the index
1872 * mappings.</p>
1873 *
1874 * @see ubidi_setInverse
1875 * @see ubidi_writeReordered
1876 * @stable ICU 2.0
1877 */
1878#define UBIDI_INSERT_LRM_FOR_NUMERIC 4
1879
1880/**
1881 * option bit for ubidi_writeReordered():
1882 * remove Bidi control characters
1883 * (this does not affect #UBIDI_INSERT_LRM_FOR_NUMERIC)
1884 *
1885 * <p>This option does not imply corresponding adjustment of the index
1886 * mappings.</p>
1887 *
1888 * @see ubidi_writeReordered
1889 * @stable ICU 2.0
1890 */
1891#define UBIDI_REMOVE_BIDI_CONTROLS 8
1892
1893/**
1894 * option bit for ubidi_writeReordered():
1895 * write the output in reverse order
1896 *
1897 * <p>This has the same effect as calling <code>ubidi_writeReordered()</code>
1898 * first without this option, and then calling
1899 * <code>ubidi_writeReverse()</code> without mirroring.
1900 * Doing this in the same step is faster and avoids a temporary buffer.
1901 * An example for using this option is output to a character terminal that
1902 * is designed for RTL scripts and stores text in reverse order.</p>
1903 *
1904 * @see ubidi_writeReordered
1905 * @stable ICU 2.0
1906 */
1907#define UBIDI_OUTPUT_REVERSE 16
1908
1909/**
1910 * Get the length of the source text processed by the last call to
1911 * <code>ubidi_setPara()</code>. This length may be different from the length
1912 * of the source text if option <code>#UBIDI_OPTION_STREAMING</code>
1913 * has been set.
1914 * <br>
1915 * Note that whenever the length of the text affects the execution or the
1916 * result of a function, it is the processed length which must be considered,
1917 * except for <code>ubidi_setPara</code> (which receives unprocessed source
1918 * text) and <code>ubidi_getLength</code> (which returns the original length
1919 * of the source text).<br>
1920 * In particular, the processed length is the one to consider in the following
1921 * cases:
1922 * <ul>
1923 * <li>maximum value of the <code>limit</code> argument of
1924 * <code>ubidi_setLine</code></li>
1925 * <li>maximum value of the <code>charIndex</code> argument of
1926 * <code>ubidi_getParagraph</code></li>
1927 * <li>maximum value of the <code>charIndex</code> argument of
1928 * <code>ubidi_getLevelAt</code></li>
1929 * <li>number of elements in the array returned by <code>ubidi_getLevels</code></li>
1930 * <li>maximum value of the <code>logicalStart</code> argument of
1931 * <code>ubidi_getLogicalRun</code></li>
1932 * <li>maximum value of the <code>logicalIndex</code> argument of
1933 * <code>ubidi_getVisualIndex</code></li>
1934 * <li>number of elements filled in the <code>*indexMap</code> argument of
1935 * <code>ubidi_getLogicalMap</code></li>
1936 * <li>length of text processed by <code>ubidi_writeReordered</code></li>
1937 * </ul>
1938 *
1939 * @param pBiDi is the paragraph <code>UBiDi</code> object.
1940 *
1941 * @return The length of the part of the source text processed by
1942 * the last call to <code>ubidi_setPara</code>.
1943 * @see ubidi_setPara
1944 * @see UBIDI_OPTION_STREAMING
1945 * @stable ICU 3.6
1946 */
1947U_CAPI int32_t U_EXPORT2
1948ubidi_getProcessedLength(const UBiDi *pBiDi);
1949
1950/**
1951 * Get the length of the reordered text resulting from the last call to
1952 * <code>ubidi_setPara()</code>. This length may be different from the length
1953 * of the source text if option <code>#UBIDI_OPTION_INSERT_MARKS</code>
1954 * or option <code>#UBIDI_OPTION_REMOVE_CONTROLS</code> has been set.
1955 * <br>
1956 * This resulting length is the one to consider in the following cases:
1957 * <ul>
1958 * <li>maximum value of the <code>visualIndex</code> argument of
1959 * <code>ubidi_getLogicalIndex</code></li>
1960 * <li>number of elements of the <code>*indexMap</code> argument of
1961 * <code>ubidi_getVisualMap</code></li>
1962 * </ul>
1963 * Note that this length stays identical to the source text length if
1964 * Bidi marks are inserted or removed using option bits of
1965 * <code>ubidi_writeReordered</code>, or if option
1966 * <code>#UBIDI_REORDER_INVERSE_NUMBERS_AS_L</code> has been set.
1967 *
1968 * @param pBiDi is the paragraph <code>UBiDi</code> object.
1969 *
1970 * @return The length of the reordered text resulting from
1971 * the last call to <code>ubidi_setPara</code>.
1972 * @see ubidi_setPara
1973 * @see UBIDI_OPTION_INSERT_MARKS
1974 * @see UBIDI_OPTION_REMOVE_CONTROLS
1975 * @stable ICU 3.6
1976 */
1977U_CAPI int32_t U_EXPORT2
1978ubidi_getResultLength(const UBiDi *pBiDi);
1979
1980U_CDECL_BEGIN
1981
1982#ifndef U_HIDE_DEPRECATED_API
1983/**
1984 * Value returned by <code>UBiDiClassCallback</code> callbacks when
1985 * there is no need to override the standard Bidi class for a given code point.
1986 *
1987 * This constant is deprecated; use u_getIntPropertyMaxValue(UCHAR_BIDI_CLASS)+1 instead.
1988 *
1989 * @see UBiDiClassCallback
1990 * @deprecated ICU 58 The numeric value may change over time, see ICU ticket #12420.
1991 */
1992#define U_BIDI_CLASS_DEFAULT U_CHAR_DIRECTION_COUNT
1993#endif // U_HIDE_DEPRECATED_API
1994
1995/**
1996 * Callback type declaration for overriding default Bidi class values with
1997 * custom ones.
1998 * <p>Usually, the function pointer will be propagated to a <code>UBiDi</code>
1999 * object by calling the <code>ubidi_setClassCallback()</code> function;
2000 * then the callback will be invoked by the UBA implementation any time the
2001 * class of a character is to be determined.</p>
2002 *
2003 * @param context is a pointer to the callback private data.
2004 *
2005 * @param c is the code point to get a Bidi class for.
2006 *
2007 * @return The directional property / Bidi class for the given code point
2008 * <code>c</code> if the default class has been overridden, or
2009 * <code>u_getIntPropertyMaxValue(UCHAR_BIDI_CLASS)+1</code>
2010 * if the standard Bidi class value for <code>c</code> is to be used.
2011 * @see ubidi_setClassCallback
2012 * @see ubidi_getClassCallback
2013 * @stable ICU 3.6
2014 */
2015typedef UCharDirection U_CALLCONV
2016UBiDiClassCallback(const void *context, UChar32 c);
2017
2018U_CDECL_END
2019
2020/**
2021 * Retrieve the Bidi class for a given code point.
2022 * <p>If a <code>#UBiDiClassCallback</code> callback is defined and returns a
2023 * value other than <code>u_getIntPropertyMaxValue(UCHAR_BIDI_CLASS)+1</code>,
2024 * that value is used; otherwise the default class determination mechanism is invoked.</p>
2025 *
2026 * @param pBiDi is the paragraph <code>UBiDi</code> object.
2027 *
2028 * @param c is the code point whose Bidi class must be retrieved.
2029 *
2030 * @return The Bidi class for character <code>c</code> based
2031 * on the given <code>pBiDi</code> instance.
2032 * @see UBiDiClassCallback
2033 * @stable ICU 3.6
2034 */
2035U_CAPI UCharDirection U_EXPORT2
2036ubidi_getCustomizedClass(UBiDi *pBiDi, UChar32 c);
2037
2038/**
2039 * Set the callback function and callback data used by the UBA
2040 * implementation for Bidi class determination.
2041 * <p>This may be useful for assigning Bidi classes to PUA characters, or
2042 * for special application needs. For instance, an application may want to
2043 * handle all spaces like L or R characters (according to the base direction)
2044 * when creating the visual ordering of logical lines which are part of a report
2045 * organized in columns: there should not be interaction between adjacent
2046 * cells.<p>
2047 *
2048 * @param pBiDi is the paragraph <code>UBiDi</code> object.
2049 *
2050 * @param newFn is the new callback function pointer.
2051 *
2052 * @param newContext is the new callback context pointer. This can be NULL.
2053 *
2054 * @param oldFn fillin: Returns the old callback function pointer. This can be
2055 * NULL.
2056 *
2057 * @param oldContext fillin: Returns the old callback's context. This can be
2058 * NULL.
2059 *
2060 * @param pErrorCode must be a valid pointer to an error code value.
2061 *
2062 * @see ubidi_getClassCallback
2063 * @stable ICU 3.6
2064 */
2065U_CAPI void U_EXPORT2
2066ubidi_setClassCallback(UBiDi *pBiDi, UBiDiClassCallback *newFn,
2067 const void *newContext, UBiDiClassCallback **oldFn,
2068 const void **oldContext, UErrorCode *pErrorCode);
2069
2070/**
2071 * Get the current callback function used for Bidi class determination.
2072 *
2073 * @param pBiDi is the paragraph <code>UBiDi</code> object.
2074 *
2075 * @param fn fillin: Returns the callback function pointer.
2076 *
2077 * @param context fillin: Returns the callback's private context.
2078 *
2079 * @see ubidi_setClassCallback
2080 * @stable ICU 3.6
2081 */
2082U_CAPI void U_EXPORT2
2083ubidi_getClassCallback(UBiDi *pBiDi, UBiDiClassCallback **fn, const void **context);
2084
2085/**
2086 * Take a <code>UBiDi</code> object containing the reordering
2087 * information for a piece of text (one or more paragraphs) set by
2088 * <code>ubidi_setPara()</code> or for a line of text set by
2089 * <code>ubidi_setLine()</code> and write a reordered string to the
2090 * destination buffer.
2091 *
2092 * This function preserves the integrity of characters with multiple
2093 * code units and (optionally) combining characters.
2094 * Characters in RTL runs can be replaced by mirror-image characters
2095 * in the destination buffer. Note that "real" mirroring has
2096 * to be done in a rendering engine by glyph selection
2097 * and that for many "mirrored" characters there are no
2098 * Unicode characters as mirror-image equivalents.
2099 * There are also options to insert or remove Bidi control
2100 * characters; see the description of the <code>destSize</code>
2101 * and <code>options</code> parameters and of the option bit flags.
2102 *
2103 * @param pBiDi A pointer to a <code>UBiDi</code> object that
2104 * is set by <code>ubidi_setPara()</code> or
2105 * <code>ubidi_setLine()</code> and contains the reordering
2106 * information for the text that it was defined for,
2107 * as well as a pointer to that text.<br><br>
2108 * The text was aliased (only the pointer was stored
2109 * without copying the contents) and must not have been modified
2110 * since the <code>ubidi_setPara()</code> call.
2111 *
2112 * @param dest A pointer to where the reordered text is to be copied.
2113 * The source text and <code>dest[destSize]</code>
2114 * must not overlap.
2115 *
2116 * @param destSize The size of the <code>dest</code> buffer,
2117 * in number of UChars.
2118 * If the <code>UBIDI_INSERT_LRM_FOR_NUMERIC</code>
2119 * option is set, then the destination length could be
2120 * as large as
2121 * <code>ubidi_getLength(pBiDi)+2*ubidi_countRuns(pBiDi)</code>.
2122 * If the <code>UBIDI_REMOVE_BIDI_CONTROLS</code> option
2123 * is set, then the destination length may be less than
2124 * <code>ubidi_getLength(pBiDi)</code>.
2125 * If none of these options is set, then the destination length
2126 * will be exactly <code>ubidi_getProcessedLength(pBiDi)</code>.
2127 *
2128 * @param options A bit set of options for the reordering that control
2129 * how the reordered text is written.
2130 * The options include mirroring the characters on a code
2131 * point basis and inserting LRM characters, which is used
2132 * especially for transforming visually stored text
2133 * to logically stored text (although this is still an
2134 * imperfect implementation of an "inverse Bidi" algorithm
2135 * because it uses the "forward Bidi" algorithm at its core).
2136 * The available options are:
2137 * <code>#UBIDI_DO_MIRRORING</code>,
2138 * <code>#UBIDI_INSERT_LRM_FOR_NUMERIC</code>,
2139 * <code>#UBIDI_KEEP_BASE_COMBINING</code>,
2140 * <code>#UBIDI_OUTPUT_REVERSE</code>,
2141 * <code>#UBIDI_REMOVE_BIDI_CONTROLS</code>
2142 *
2143 * @param pErrorCode must be a valid pointer to an error code value.
2144 *
2145 * @return The length of the output string.
2146 *
2147 * @see ubidi_getProcessedLength
2148 * @stable ICU 2.0
2149 */
2150U_CAPI int32_t U_EXPORT2
2151ubidi_writeReordered(UBiDi *pBiDi,
2152 UChar *dest, int32_t destSize,
2153 uint16_t options,
2154 UErrorCode *pErrorCode);
2155
2156/**
2157 * Reverse a Right-To-Left run of Unicode text.
2158 *
2159 * This function preserves the integrity of characters with multiple
2160 * code units and (optionally) combining characters.
2161 * Characters can be replaced by mirror-image characters
2162 * in the destination buffer. Note that "real" mirroring has
2163 * to be done in a rendering engine by glyph selection
2164 * and that for many "mirrored" characters there are no
2165 * Unicode characters as mirror-image equivalents.
2166 * There are also options to insert or remove Bidi control
2167 * characters.
2168 *
2169 * This function is the implementation for reversing RTL runs as part
2170 * of <code>ubidi_writeReordered()</code>. For detailed descriptions
2171 * of the parameters, see there.
2172 * Since no Bidi controls are inserted here, the output string length
2173 * will never exceed <code>srcLength</code>.
2174 *
2175 * @see ubidi_writeReordered
2176 *
2177 * @param src A pointer to the RTL run text.
2178 *
2179 * @param srcLength The length of the RTL run.
2180 *
2181 * @param dest A pointer to where the reordered text is to be copied.
2182 * <code>src[srcLength]</code> and <code>dest[destSize]</code>
2183 * must not overlap.
2184 *
2185 * @param destSize The size of the <code>dest</code> buffer,
2186 * in number of UChars.
2187 * If the <code>UBIDI_REMOVE_BIDI_CONTROLS</code> option
2188 * is set, then the destination length may be less than
2189 * <code>srcLength</code>.
2190 * If this option is not set, then the destination length
2191 * will be exactly <code>srcLength</code>.
2192 *
2193 * @param options A bit set of options for the reordering that control
2194 * how the reordered text is written.
2195 * See the <code>options</code> parameter in <code>ubidi_writeReordered()</code>.
2196 *
2197 * @param pErrorCode must be a valid pointer to an error code value.
2198 *
2199 * @return The length of the output string.
2200 * @stable ICU 2.0
2201 */
2202U_CAPI int32_t U_EXPORT2
2203ubidi_writeReverse(const UChar *src, int32_t srcLength,
2204 UChar *dest, int32_t destSize,
2205 uint16_t options,
2206 UErrorCode *pErrorCode);
2207
2208/*#define BIDI_SAMPLE_CODE*/
2209/*@}*/
2210
2211#endif
2212