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	*/
340	typedef 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	*/
429	enum 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 */
471	typedef 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	*/
483	struct UBiDi;
484
485	/** @stable ICU 2.0 */
486	typedef 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	*/
503	U_CAPI UBiDi * U_EXPORT2
504	ubidi_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	*/
540	U_CAPI UBiDi * U_EXPORT2
541	ubidi_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	*/
563	U_CAPI void U_EXPORT2
564	ubidi_close(UBiDi *pBiDi);
565
566	#if U_SHOW_CPLUSPLUS_API
567
568	U_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	*/
579	U_DEFINE_LOCAL_OPEN_POINTER(LocalUBiDiPointer, UBiDi, ubidi_close);
580
581	U_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	*/
633	U_CAPI void U_EXPORT2
634	ubidi_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
652	U_CAPI UBool U_EXPORT2
653	ubidi_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	*/
675	U_CAPI void U_EXPORT2
676	ubidi_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	*/
689	U_CAPI UBool U_EXPORT2
690	ubidi_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	*/
699	typedef 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	*/
893	U_CAPI void U_EXPORT2
894	ubidi_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	*/
904	U_CAPI UBiDiReorderingMode U_EXPORT2
905	ubidi_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	*/
914	typedef 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	*/
1049	U_CAPI void U_EXPORT2
1050	ubidi_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	*/
1060	U_CAPI uint32_t U_EXPORT2
1061	ubidi_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	*/
1147	U_CAPI void U_EXPORT2
1148	ubidi_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	*/
1235	U_CAPI void U_EXPORT2
1236	ubidi_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	*/
1286	U_CAPI void U_EXPORT2
1287	ubidi_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	*/
1307	U_CAPI UBiDiDirection U_EXPORT2
1308	ubidi_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	*/
1337	U_CAPI UBiDiDirection U_EXPORT2
1338	ubidi_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	*/
1351	U_CAPI const UChar * U_EXPORT2
1352	ubidi_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	*/
1362	U_CAPI int32_t U_EXPORT2
1363	ubidi_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	*/
1380	U_CAPI UBiDiLevel U_EXPORT2
1381	ubidi_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	*/
1391	U_CAPI int32_t U_EXPORT2
1392	ubidi_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	*/
1428	U_CAPI int32_t U_EXPORT2
1429	ubidi_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	*/
1460	U_CAPI void U_EXPORT2
1461	ubidi_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	*/
1480	U_CAPI UBiDiLevel U_EXPORT2
1481	ubidi_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	*/
1501	U_CAPI const UBiDiLevel * U_EXPORT2
1502	ubidi_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	*/
1528	U_CAPI void U_EXPORT2
1529	ubidi_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	*/
1547	U_CAPI int32_t U_EXPORT2
1548	ubidi_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	*/
1606	U_CAPI UBiDiDirection U_EXPORT2
1607	ubidi_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	*/
1647	U_CAPI int32_t U_EXPORT2
1648	ubidi_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	*/
1682	U_CAPI int32_t U_EXPORT2
1683	ubidi_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	*/
1725	U_CAPI void U_EXPORT2
1726	ubidi_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	*/
1761	U_CAPI void U_EXPORT2
1762	ubidi_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	*/
1784	U_CAPI void U_EXPORT2
1785	ubidi_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	*/
1807	U_CAPI void U_EXPORT2
1808	ubidi_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	*/
1842	U_CAPI void U_EXPORT2
1843	ubidi_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	*/
1947	U_CAPI int32_t U_EXPORT2
1948	ubidi_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	*/
1977	U_CAPI int32_t U_EXPORT2
1978	ubidi_getResultLength(const UBiDi *pBiDi);
1979
1980	U_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	*/
2015	typedef UCharDirection U_CALLCONV
2016	UBiDiClassCallback(const void *context, UChar32 c);
2017
2018	U_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	*/
2035	U_CAPI UCharDirection U_EXPORT2
2036	ubidi_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	*/
2065	U_CAPI void U_EXPORT2
2066	ubidi_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	*/
2082	U_CAPI void U_EXPORT2
2083	ubidi_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	*/
2150	U_CAPI int32_t U_EXPORT2
2151	ubidi_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	*/
2202	U_CAPI int32_t U_EXPORT2
2203	ubidi_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