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 // © 2016 and later: Unicode, Inc. and others.
 // License & terms of use: http://www.unicode.org/copyright.html
 /*
 ******************************************************************************
 *
 *   Copyright (C) 1999-2013, International Business Machines
 *   Corporation and others.  All Rights Reserved.
 *
 ******************************************************************************
 *   file name:  ubidi.h
 *   encoding:   UTF-8
 *   tab size:   8 (not used)
 *   indentation:4
 *
 *   created on: 1999jul27
 *   created by: Markus W. Scherer, updated by Matitiahu Allouche
 */
 
 #ifndef UBIDI_H
 #define UBIDI_H
 
 #include "unicode/utypes.h"
 #include "unicode/uchar.h"
 
 #if U_SHOW_CPLUSPLUS_API
 #include "unicode/localpointer.h"
 #endif   // U_SHOW_CPLUSPLUS_API
 
 /**
  *\file
  * \brief C API: Bidi algorithm
  *
  * <h2>Bidi algorithm for ICU</h2>
  *
  * This is an implementation of the Unicode Bidirectional Algorithm.
  * The algorithm is defined in the
  * <a href="http://www.unicode.org/unicode/reports/tr9/">Unicode Standard Annex #9</a>.<p>
  *
  * Note: Libraries that perform a bidirectional algorithm and
  * reorder strings accordingly are sometimes called "Storage Layout Engines".
  * ICU's Bidi and shaping (u_shapeArabic()) APIs can be used at the core of such
  * "Storage Layout Engines".
  *
  * <h3>General remarks about the API:</h3>
  *
  * In functions with an error code parameter,
  * the <code>pErrorCode</code> pointer must be valid
  * and the value that it points to must not indicate a failure before
  * the function call. Otherwise, the function returns immediately.
  * After the function call, the value indicates success or failure.<p>
  *
  * The &quot;limit&quot; of a sequence of characters is the position just after their
  * last character, i.e., one more than that position.<p>
  *
  * Some of the API functions provide access to &quot;runs&quot;.
  * Such a &quot;run&quot; is defined as a sequence of characters
  * that are at the same embedding level
  * after performing the Bidi algorithm.<p>
  *
  * @author Markus W. Scherer
  * @version 1.0
  *
  *
  * <h4> Sample code for the ICU Bidi API </h4>
  *
  * <h5>Rendering a paragraph with the ICU Bidi API</h5>
  *
  * This is (hypothetical) sample code that illustrates
  * how the ICU Bidi API could be used to render a paragraph of text.
  * Rendering code depends highly on the graphics system,
  * therefore this sample code must make a lot of assumptions,
  * which may or may not match any existing graphics system's properties.
  *
  * <p>The basic assumptions are:</p>
  * <ul>
  * <li>Rendering is done from left to right on a horizontal line.</li>
  * <li>A run of single-style, unidirectional text can be rendered at once.</li>
  * <li>Such a run of text is passed to the graphics system with
  *     characters (code units) in logical order.</li>
  * <li>The line-breaking algorithm is very complicated
  *     and Locale-dependent -
  *     and therefore its implementation omitted from this sample code.</li>
  * </ul>
  *
  * <pre>
  * \code
  *#include <unicode/ubidi.h>
  *
  *typedef enum {
  *     styleNormal=0, styleSelected=1,
  *     styleBold=2, styleItalics=4,
  *     styleSuper=8, styleSub=16
  *} Style;
  *
  *typedef struct { int32_t limit; Style style; } StyleRun;
  *
  *int getTextWidth(const UChar *text, int32_t start, int32_t limit,
  *                  const StyleRun *styleRuns, int styleRunCount);
  *
  * // set *pLimit and *pStyleRunLimit for a line
  * // from text[start] and from styleRuns[styleRunStart]
  * // using ubidi_getLogicalRun(para, ...)
  *void getLineBreak(const UChar *text, int32_t start, int32_t *pLimit,
  *                  UBiDi *para,
  *                  const StyleRun *styleRuns, int styleRunStart, int *pStyleRunLimit,
  *                  int *pLineWidth);
  *
  * // render runs on a line sequentially, always from left to right
  *
  * // prepare rendering a new line
  * void startLine(UBiDiDirection textDirection, int lineWidth);
  *
  * // render a run of text and advance to the right by the run width
  * // the text[start..limit-1] is always in logical order
  * void renderRun(const UChar *text, int32_t start, int32_t limit,
  *               UBiDiDirection textDirection, Style style);
  *
  * // We could compute a cross-product
  * // from the style runs with the directional runs
  * // and then reorder it.
  * // Instead, here we iterate over each run type
  * // and render the intersections -
  * // with shortcuts in simple (and common) cases.
  * // renderParagraph() is the main function.
  *
  * // render a directional run with
  * // (possibly) multiple style runs intersecting with it
  * void renderDirectionalRun(const UChar *text,
  *                           int32_t start, int32_t limit,
  *                           UBiDiDirection direction,
  *                           const StyleRun *styleRuns, int styleRunCount) {
  *     int i;
  *
  *     // iterate over style runs
  *     if(direction==UBIDI_LTR) {
  *         int styleLimit;
  *
  *         for(i=0; i<styleRunCount; ++i) {
  *             styleLimit=styleRuns[i].limit;
  *             if(start<styleLimit) {
  *                 if(styleLimit>limit) { styleLimit=limit; }
  *                 renderRun(text, start, styleLimit,
  *                           direction, styleRuns[i].style);
  *                 if(styleLimit==limit) { break; }
  *                 start=styleLimit;
  *             }
  *         }
  *     } else {
  *         int styleStart;
  *
  *         for(i=styleRunCount-1; i>=0; --i) {
  *             if(i>0) {
  *                 styleStart=styleRuns[i-1].limit;
  *             } else {
  *                 styleStart=0;
  *             }
  *             if(limit>=styleStart) {
  *                 if(styleStart<start) { styleStart=start; }
  *                 renderRun(text, styleStart, limit,
  *                           direction, styleRuns[i].style);
  *                 if(styleStart==start) { break; }
  *                 limit=styleStart;
  *             }
  *         }
  *     }
  * }
  *
  * // the line object represents text[start..limit-1]
  * void renderLine(UBiDi *line, const UChar *text,
  *                 int32_t start, int32_t limit,
  *                 const StyleRun *styleRuns, int styleRunCount,
  *                 UErrorCode *pErrorCode) {
  *     UBiDiDirection direction=ubidi_getDirection(line);
  *     if(direction!=UBIDI_MIXED) {
  *         // unidirectional
  *         if(styleRunCount<=1) {
  *             renderRun(text, start, limit, direction, styleRuns[0].style);
  *         } else {
  *             renderDirectionalRun(text, start, limit,
  *                                  direction, styleRuns, styleRunCount);
  *         }
  *     } else {
  *         // mixed-directional
  *         int32_t count, i, length;
  *         UBiDiLevel level;
  *
  *         count=ubidi_countRuns(line, pErrorCode);
  *         if(U_SUCCESS(*pErrorCode)) {
  *             if(styleRunCount<=1) {
  *                 Style style=styleRuns[0].style;
  *
  *                 // iterate over directional runs
  *                for(i=0; i<count; ++i) {
  *                    direction=ubidi_getVisualRun(line, i, &start, &length);
  *                     renderRun(text, start, start+length, direction, style);
  *                }
  *             } else {
  *                 int32_t j;
  *
  *                 // iterate over both directional and style runs
  *                 for(i=0; i<count; ++i) {
  *                     direction=ubidi_getVisualRun(line, i, &start, &length);
  *                     renderDirectionalRun(text, start, start+length,
  *                                          direction, styleRuns, styleRunCount);
  *                 }
  *             }
  *         }
  *     }
  * }
  *
  *void renderParagraph(const UChar *text, int32_t length,
  *                     UBiDiDirection textDirection,
  *                      const StyleRun *styleRuns, int styleRunCount,
  *                      int lineWidth,
  *                      UErrorCode *pErrorCode) {
  *     UBiDi *para;
  *
  *     if(pErrorCode==NULL || U_FAILURE(*pErrorCode) || length<=0) {
  *         return;
  *     }
  *
  *     para=ubidi_openSized(length, 0, pErrorCode);
  *     if(para==NULL) { return; }
  *
  *     ubidi_setPara(para, text, length,
  *                   textDirection ? UBIDI_DEFAULT_RTL : UBIDI_DEFAULT_LTR,
  *                   NULL, pErrorCode);
  *     if(U_SUCCESS(*pErrorCode)) {
  *         UBiDiLevel paraLevel=1&ubidi_getParaLevel(para);
  *         StyleRun styleRun={ length, styleNormal };
  *         int width;
  *
  *         if(styleRuns==NULL || styleRunCount<=0) {
  *            styleRunCount=1;
  *             styleRuns=&styleRun;
  *         }
  *
  *        // assume styleRuns[styleRunCount-1].limit>=length
  *
  *         width=getTextWidth(text, 0, length, styleRuns, styleRunCount);
  *         if(width<=lineWidth) {
  *             // everything fits onto one line
  *
  *            // prepare rendering a new line from either left or right
  *             startLine(paraLevel, width);
  *
  *             renderLine(para, text, 0, length,
  *                        styleRuns, styleRunCount, pErrorCode);
  *         } else {
  *             UBiDi *line;
  *
  *             // we need to render several lines
  *             line=ubidi_openSized(length, 0, pErrorCode);
  *             if(line!=NULL) {
  *                 int32_t start=0, limit;
  *                 int styleRunStart=0, styleRunLimit;
  *
  *                 for(;;) {
  *                     limit=length;
  *                     styleRunLimit=styleRunCount;
  *                     getLineBreak(text, start, &limit, para,
  *                                  styleRuns, styleRunStart, &styleRunLimit,
  *                                 &width);
  *                     ubidi_setLine(para, start, limit, line, pErrorCode);
  *                     if(U_SUCCESS(*pErrorCode)) {
  *                         // prepare rendering a new line
  *                         // from either left or right
  *                         startLine(paraLevel, width);
  *
  *                         renderLine(line, text, start, limit,
  *                                    styleRuns+styleRunStart,
  *                                    styleRunLimit-styleRunStart, pErrorCode);
  *                     }
  *                     if(limit==length) { break; }
  *                     start=limit;
  *                     styleRunStart=styleRunLimit-1;
  *                     if(start>=styleRuns[styleRunStart].limit) {
  *                         ++styleRunStart;
  *                     }
  *                 }
  *
  *                 ubidi_close(line);
  *             }
  *        }
  *    }
  *
  *     ubidi_close(para);
  *}
  *\endcode
  * </pre>
  */
 
 /*DOCXX_TAG*/
 /*@{*/
 
 /**
  * UBiDiLevel is the type of the level values in this
  * Bidi implementation.
  * It holds an embedding level and indicates the visual direction
  * by its bit&nbsp;0 (even/odd value).<p>
  *
  * It can also hold non-level values for the
  * <code>paraLevel</code> and <code>embeddingLevels</code>
  * arguments of <code>ubidi_setPara()</code>; there:
  * <ul>
  * <li>bit&nbsp;7 of an <code>embeddingLevels[]</code>
  * value indicates whether the using application is
  * specifying the level of a character to <i>override</i> whatever the
  * Bidi implementation would resolve it to.</li>
  * <li><code>paraLevel</code> can be set to the
  * pseudo-level values <code>UBIDI_DEFAULT_LTR</code>
  * and <code>UBIDI_DEFAULT_RTL</code>.</li>
  * </ul>
  *
  * @see ubidi_setPara
  *
  * <p>The related constants are not real, valid level values.
  * <code>UBIDI_DEFAULT_XXX</code> can be used to specify
  * a default for the paragraph level for
  * when the <code>ubidi_setPara()</code> function
  * shall determine it but there is no
  * strongly typed character in the input.<p>
  *
  * Note that the value for <code>UBIDI_DEFAULT_LTR</code> is even
  * and the one for <code>UBIDI_DEFAULT_RTL</code> is odd,
  * just like with normal LTR and RTL level values -
  * these special values are designed that way. Also, the implementation
  * assumes that UBIDI_MAX_EXPLICIT_LEVEL is odd.
  *
  * Note: The numeric values of the related constants will not change:
  * They are tied to the use of 7-bit byte values (plus the override bit)
  * and of the UBiDiLevel=uint8_t data type in this API.
  *
  * @see UBIDI_DEFAULT_LTR
  * @see UBIDI_DEFAULT_RTL
  * @see UBIDI_LEVEL_OVERRIDE
  * @see UBIDI_MAX_EXPLICIT_LEVEL
  * @stable ICU 2.0
  */
 typedef uint8_t UBiDiLevel;
 
 /** Paragraph level setting.<p>
  *
  * Constant indicating that the base direction depends on the first strong
  * directional character in the text according to the Unicode Bidirectional
  * Algorithm. If no strong directional character is present,
  * then set the paragraph level to 0 (left-to-right).<p>
  *
  * If this value is used in conjunction with reordering modes
  * <code>UBIDI_REORDER_INVERSE_LIKE_DIRECT</code> or
  * <code>UBIDI_REORDER_INVERSE_FOR_NUMBERS_SPECIAL</code>, the text to reorder
  * is assumed to be visual LTR, and the text after reordering is required
  * to be the corresponding logical string with appropriate contextual
  * direction. The direction of the result string will be RTL if either
  * the righmost or leftmost strong character of the source text is RTL
  * or Arabic Letter, the direction will be LTR otherwise.<p>
  *
  * If reordering option <code>UBIDI_OPTION_INSERT_MARKS</code> is set, an RLM may
  * be added at the beginning of the result string to ensure round trip
  * (that the result string, when reordered back to visual, will produce
  * the original source text).
  * @see UBIDI_REORDER_INVERSE_LIKE_DIRECT
  * @see UBIDI_REORDER_INVERSE_FOR_NUMBERS_SPECIAL
  * @stable ICU 2.0
  */
 #define UBIDI_DEFAULT_LTR 0xfe
 
 /** Paragraph level setting.<p>
  *
  * Constant indicating that the base direction depends on the first strong
  * directional character in the text according to the Unicode Bidirectional
  * Algorithm. If no strong directional character is present,
  * then set the paragraph level to 1 (right-to-left).<p>
  *
  * If this value is used in conjunction with reordering modes
  * <code>UBIDI_REORDER_INVERSE_LIKE_DIRECT</code> or
  * <code>UBIDI_REORDER_INVERSE_FOR_NUMBERS_SPECIAL</code>, the text to reorder
  * is assumed to be visual LTR, and the text after reordering is required
  * to be the corresponding logical string with appropriate contextual
  * direction. The direction of the result string will be RTL if either
  * the righmost or leftmost strong character of the source text is RTL
  * or Arabic Letter, or if the text contains no strong character;
  * the direction will be LTR otherwise.<p>
  *
  * If reordering option <code>UBIDI_OPTION_INSERT_MARKS</code> is set, an RLM may
  * be added at the beginning of the result string to ensure round trip
  * (that the result string, when reordered back to visual, will produce
  * the original source text).
  * @see UBIDI_REORDER_INVERSE_LIKE_DIRECT
  * @see UBIDI_REORDER_INVERSE_FOR_NUMBERS_SPECIAL
  * @stable ICU 2.0
  */
 #define UBIDI_DEFAULT_RTL 0xff
 
 /**
  * Maximum explicit embedding level.
  * Same as the max_depth value in the
  * <a href="http://www.unicode.org/reports/tr9/#BD2">Unicode Bidirectional Algorithm</a>.
  * (The maximum resolved level can be up to <code>UBIDI_MAX_EXPLICIT_LEVEL+1</code>).
  * @stable ICU 2.0
  */
 #define UBIDI_MAX_EXPLICIT_LEVEL 125
 
 /** Bit flag for level input.
  *  Overrides directional properties.
  * @stable ICU 2.0
  */
 #define UBIDI_LEVEL_OVERRIDE 0x80
 
 /**
  * Special value which can be returned by the mapping functions when a logical
  * index has no corresponding visual index or vice-versa. This may happen
  * for the logical-to-visual mapping of a Bidi control when option
  * <code>#UBIDI_OPTION_REMOVE_CONTROLS</code> is specified. This can also happen
  * for the visual-to-logical mapping of a Bidi mark (LRM or RLM) inserted
  * by option <code>#UBIDI_OPTION_INSERT_MARKS</code>.
  * @see ubidi_getVisualIndex
  * @see ubidi_getVisualMap
  * @see ubidi_getLogicalIndex
  * @see ubidi_getLogicalMap
  * @stable ICU 3.6
  */
 #define UBIDI_MAP_NOWHERE   (-1)
 
 /**
  * <code>UBiDiDirection</code> values indicate the text direction.
  * @stable ICU 2.0
  */
 enum UBiDiDirection {
   /** Left-to-right text. This is a 0 value.
    * <ul>
    * <li>As return value for <code>ubidi_getDirection()</code>, it means
    *     that the source string contains no right-to-left characters, or
    *     that the source string is empty and the paragraph level is even.
    * <li> As return value for <code>ubidi_getBaseDirection()</code>, it
    *      means that the first strong character of the source string has
    *      a left-to-right direction.
    * </ul>
    * @stable ICU 2.0
    */
   UBIDI_LTR,
   /** Right-to-left text. This is a 1 value.
    * <ul>
    * <li>As return value for <code>ubidi_getDirection()</code>, it means
    *     that the source string contains no left-to-right characters, or
    *     that the source string is empty and the paragraph level is odd.
    * <li> As return value for <code>ubidi_getBaseDirection()</code>, it
    *      means that the first strong character of the source string has
    *      a right-to-left direction.
    * </ul>
    * @stable ICU 2.0
    */
   UBIDI_RTL,
   /** Mixed-directional text.
    * <p>As return value for <code>ubidi_getDirection()</code>, it means
    *    that the source string contains both left-to-right and
    *    right-to-left characters.
    * @stable ICU 2.0
    */
   UBIDI_MIXED,
   /** No strongly directional text.
    * <p>As return value for <code>ubidi_getBaseDirection()</code>, it means
    *    that the source string is missing or empty, or contains neither left-to-right
    *    nor right-to-left characters.
    * @stable ICU 4.6
    */
   UBIDI_NEUTRAL
 };
 
 /** @stable ICU 2.0 */
 typedef enum UBiDiDirection UBiDiDirection;
 
 /**
  * Forward declaration of the <code>UBiDi</code> structure for the declaration of
  * the API functions. Its fields are implementation-specific.<p>
  * This structure holds information about a paragraph (or multiple paragraphs)
  * of text with Bidi-algorithm-related details, or about one line of
  * such a paragraph.<p>
  * Reordering can be done on a line, or on one or more paragraphs which are
  * then interpreted each as one single line.
  * @stable ICU 2.0
  */
 struct UBiDi;
 
 /** @stable ICU 2.0 */
 typedef struct UBiDi UBiDi;
 
 /**
  * Allocate a <code>UBiDi</code> structure.
  * Such an object is initially empty. It is assigned
  * the Bidi properties of a piece of text containing one or more paragraphs
  * by <code>ubidi_setPara()</code>
  * or the Bidi properties of a line within a paragraph by
  * <code>ubidi_setLine()</code>.<p>
  * This object can be reused for as long as it is not deallocated
  * by calling <code>ubidi_close()</code>.<p>
  * <code>ubidi_setPara()</code> and <code>ubidi_setLine()</code> will allocate
  * additional memory for internal structures as necessary.
  *
  * @return An empty <code>UBiDi</code> object.
  * @stable ICU 2.0
  */
 U_CAPI UBiDi * U_EXPORT2
 ubidi_open(void);
 
 /**
  * Allocate a <code>UBiDi</code> structure with preallocated memory
  * for internal structures.
  * This function provides a <code>UBiDi</code> object like <code>ubidi_open()</code>
  * with no arguments, but it also preallocates memory for internal structures
  * according to the sizings supplied by the caller.<p>
  * Subsequent functions will not allocate any more memory, and are thus
  * guaranteed not to fail because of lack of memory.<p>
  * The preallocation can be limited to some of the internal memory
  * by setting some values to 0 here. That means that if, e.g.,
  * <code>maxRunCount</code> cannot be reasonably predetermined and should not
  * be set to <code>maxLength</code> (the only failproof value) to avoid
  * wasting memory, then <code>maxRunCount</code> could be set to 0 here
  * and the internal structures that are associated with it will be allocated
  * on demand, just like with <code>ubidi_open()</code>.
  *
  * @param maxLength is the maximum text or line length that internal memory
  *        will be preallocated for. An attempt to associate this object with a
  *        longer text will fail, unless this value is 0, which leaves the allocation
  *        up to the implementation.
  *
  * @param maxRunCount is the maximum anticipated number of same-level runs
  *        that internal memory will be preallocated for. An attempt to access
  *        visual runs on an object that was not preallocated for as many runs
  *        as the text was actually resolved to will fail,
  *        unless this value is 0, which leaves the allocation up to the implementation.<br><br>
  *        The number of runs depends on the actual text and maybe anywhere between
  *        1 and <code>maxLength</code>. It is typically small.
  *
  * @param pErrorCode must be a valid pointer to an error code value.
  *
  * @return An empty <code>UBiDi</code> object with preallocated memory.
  * @stable ICU 2.0
  */
 U_CAPI UBiDi * U_EXPORT2
 ubidi_openSized(int32_t maxLength, int32_t maxRunCount, UErrorCode *pErrorCode);
 
 /**
  * <code>ubidi_close()</code> must be called to free the memory
  * associated with a UBiDi object.<p>
  *
  * <strong>Important: </strong>
  * A parent <code>UBiDi</code> object must not be destroyed or reused if
  * it still has children.
  * If a <code>UBiDi</code> object has become the <i>child</i>
  * of another one (its <i>parent</i>) by calling
  * <code>ubidi_setLine()</code>, then the child object must
  * be destroyed (closed) or reused (by calling
  * <code>ubidi_setPara()</code> or <code>ubidi_setLine()</code>)
  * before the parent object.
  *
  * @param pBiDi is a <code>UBiDi</code> object.
  *
  * @see ubidi_setPara
  * @see ubidi_setLine
  * @stable ICU 2.0
  */
 U_CAPI void U_EXPORT2
 ubidi_close(UBiDi *pBiDi);
 
 #if U_SHOW_CPLUSPLUS_API
 
 U_NAMESPACE_BEGIN
 
 /**
  * \class LocalUBiDiPointer
  * "Smart pointer" class, closes a UBiDi via ubidi_close().
  * For most methods see the LocalPointerBase base class.
  *
  * @see LocalPointerBase
  * @see LocalPointer
  * @stable ICU 4.4
  */
 U_DEFINE_LOCAL_OPEN_POINTER(LocalUBiDiPointer, UBiDi, ubidi_close);
 
 U_NAMESPACE_END
 
 #endif
 
 /**
  * Modify the operation of the Bidi algorithm such that it
  * approximates an "inverse Bidi" algorithm. This function
  * must be called before <code>ubidi_setPara()</code>.
  *
  * <p>The normal operation of the Bidi algorithm as described
  * in the Unicode Technical Report is to take text stored in logical
  * (keyboard, typing) order and to determine the reordering of it for visual
  * rendering.
  * Some legacy systems store text in visual order, and for operations
  * with standard, Unicode-based algorithms, the text needs to be transformed
  * to logical order. This is effectively the inverse algorithm of the
  * described Bidi algorithm. Note that there is no standard algorithm for
  * this "inverse Bidi" and that the current implementation provides only an
  * approximation of "inverse Bidi".</p>
  *
  * <p>With <code>isInverse</code> set to <code>true</code>,
  * this function changes the behavior of some of the subsequent functions
  * in a way that they can be used for the inverse Bidi algorithm.
  * Specifically, runs of text with numeric characters will be treated in a
  * special way and may need to be surrounded with LRM characters when they are
  * written in reordered sequence.</p>
  *
  * <p>Output runs should be retrieved using <code>ubidi_getVisualRun()</code>.
  * Since the actual input for "inverse Bidi" is visually ordered text and
  * <code>ubidi_getVisualRun()</code> gets the reordered runs, these are actually
  * the runs of the logically ordered output.</p>
  *
  * <p>Calling this function with argument <code>isInverse</code> set to
  * <code>true</code> is equivalent to calling
  * <code>ubidi_setReorderingMode</code> with argument
  * <code>reorderingMode</code>
  * set to <code>#UBIDI_REORDER_INVERSE_NUMBERS_AS_L</code>.<br>
  * Calling this function with argument <code>isInverse</code> set to
  * <code>false</code> is equivalent to calling
  * <code>ubidi_setReorderingMode</code> with argument
  * <code>reorderingMode</code>
  * set to <code>#UBIDI_REORDER_DEFAULT</code>.
  *
  * @param pBiDi is a <code>UBiDi</code> object.
  *
  * @param isInverse specifies "forward" or "inverse" Bidi operation.
  *
  * @see ubidi_setPara
  * @see ubidi_writeReordered
  * @see ubidi_setReorderingMode
  * @stable ICU 2.0
  */
 U_CAPI void U_EXPORT2
 ubidi_setInverse(UBiDi *pBiDi, UBool isInverse);
 
 /**
  * Is this Bidi object set to perform the inverse Bidi algorithm?
  * <p>Note: calling this function after setting the reordering mode with
  * <code>ubidi_setReorderingMode</code> will return <code>true</code> if the
  * reordering mode was set to <code>#UBIDI_REORDER_INVERSE_NUMBERS_AS_L</code>,
  * <code>false</code> for all other values.</p>
  *
  * @param pBiDi is a <code>UBiDi</code> object.
  * @return true if the Bidi object is set to perform the inverse Bidi algorithm
  * by handling numbers as L.
  *
  * @see ubidi_setInverse
  * @see ubidi_setReorderingMode
  * @stable ICU 2.0
  */
 
 U_CAPI UBool U_EXPORT2
 ubidi_isInverse(UBiDi *pBiDi);
 
 /**
  * Specify whether block separators must be allocated level zero,
  * so that successive paragraphs will progress from left to right.
  * This function must be called before <code>ubidi_setPara()</code>.
  * Paragraph separators (B) may appear in the text.  Setting them to level zero
  * means that all paragraph separators (including one possibly appearing
  * in the last text position) are kept in the reordered text after the text
  * that they follow in the source text.
  * When this feature is not enabled, a paragraph separator at the last
  * position of the text before reordering will go to the first position
  * of the reordered text when the paragraph level is odd.
  *
  * @param pBiDi is a <code>UBiDi</code> object.
  *
  * @param orderParagraphsLTR specifies whether paragraph separators (B) must
  * receive level 0, so that successive paragraphs progress from left to right.
  *
  * @see ubidi_setPara
  * @stable ICU 3.4
  */
 U_CAPI void U_EXPORT2
 ubidi_orderParagraphsLTR(UBiDi *pBiDi, UBool orderParagraphsLTR);
 
 /**
  * Is this Bidi object set to allocate level 0 to block separators so that
  * successive paragraphs progress from left to right?
  *
  * @param pBiDi is a <code>UBiDi</code> object.
  * @return true if the Bidi object is set to allocate level 0 to block
  *         separators.
  *
  * @see ubidi_orderParagraphsLTR
  * @stable ICU 3.4
  */
 U_CAPI UBool U_EXPORT2
 ubidi_isOrderParagraphsLTR(UBiDi *pBiDi);
 
 /**
  * <code>UBiDiReorderingMode</code> values indicate which variant of the Bidi
  * algorithm to use.
  *
  * @see ubidi_setReorderingMode
  * @stable ICU 3.6
  */
 typedef enum UBiDiReorderingMode {
     /** Regular Logical to Visual Bidi algorithm according to Unicode.
       * This is a 0 value.
       * @stable ICU 3.6 */
     UBIDI_REORDER_DEFAULT = 0,
     /** Logical to Visual algorithm which handles numbers in a way which
       * mimics the behavior of Windows XP.
       * @stable ICU 3.6 */
     UBIDI_REORDER_NUMBERS_SPECIAL,
     /** Logical to Visual algorithm grouping numbers with adjacent R characters
       * (reversible algorithm).
       * @stable ICU 3.6 */
     UBIDI_REORDER_GROUP_NUMBERS_WITH_R,
     /** Reorder runs only to transform a Logical LTR string to the Logical RTL
       * string with the same display, or vice-versa.<br>
       * If this mode is set together with option
       * <code>#UBIDI_OPTION_INSERT_MARKS</code>, some Bidi controls in the source
       * text may be removed and other controls may be added to produce the
       * minimum combination which has the required display.
       * @stable ICU 3.6 */
     UBIDI_REORDER_RUNS_ONLY,
     /** Visual to Logical algorithm which handles numbers like L
       * (same algorithm as selected by <code>ubidi_setInverse(true)</code>.
       * @see ubidi_setInverse
       * @stable ICU 3.6 */
     UBIDI_REORDER_INVERSE_NUMBERS_AS_L,
     /** Visual to Logical algorithm equivalent to the regular Logical to Visual
       * algorithm.
       * @stable ICU 3.6 */
     UBIDI_REORDER_INVERSE_LIKE_DIRECT,
     /** Inverse Bidi (Visual to Logical) algorithm for the
       * <code>UBIDI_REORDER_NUMBERS_SPECIAL</code> Bidi algorithm.
       * @stable ICU 3.6 */
     UBIDI_REORDER_INVERSE_FOR_NUMBERS_SPECIAL,
 #ifndef U_HIDE_DEPRECATED_API
     /**
      * Number of values for reordering mode.
      * @deprecated ICU 58 The numeric value may change over time, see ICU ticket #12420.
      */
     UBIDI_REORDER_COUNT
 #endif  // U_HIDE_DEPRECATED_API
 } UBiDiReorderingMode;
 
 /**
  * Modify the operation of the Bidi algorithm such that it implements some
  * variant to the basic Bidi algorithm or approximates an "inverse Bidi"
  * algorithm, depending on different values of the "reordering mode".
  * This function must be called before <code>ubidi_setPara()</code>, and stays
  * in effect until called again with a different argument.
  *
  * <p>The normal operation of the Bidi algorithm as described
  * in the Unicode Standard Annex #9 is to take text stored in logical
  * (keyboard, typing) order and to determine how to reorder it for visual
  * rendering.</p>
  *
  * <p>With the reordering mode set to a value other than
  * <code>#UBIDI_REORDER_DEFAULT</code>, this function changes the behavior of
  * some of the subsequent functions in a way such that they implement an
  * inverse Bidi algorithm or some other algorithm variants.</p>
  *
  * <p>Some legacy systems store text in visual order, and for operations
  * with standard, Unicode-based algorithms, the text needs to be transformed
  * into logical order. This is effectively the inverse algorithm of the
  * described Bidi algorithm. Note that there is no standard algorithm for
  * this "inverse Bidi", so a number of variants are implemented here.</p>
  *
  * <p>In other cases, it may be desirable to emulate some variant of the
  * Logical to Visual algorithm (e.g. one used in MS Windows), or perform a
  * Logical to Logical transformation.</p>
  *
  * <ul>
  * <li>When the reordering mode is set to <code>#UBIDI_REORDER_DEFAULT</code>,
  * the standard Bidi Logical to Visual algorithm is applied.</li>
  *
  * <li>When the reordering mode is set to
  * <code>#UBIDI_REORDER_NUMBERS_SPECIAL</code>,
  * the algorithm used to perform Bidi transformations when calling
  * <code>ubidi_setPara</code> should approximate the algorithm used in
  * Microsoft Windows XP rather than strictly conform to the Unicode Bidi
  * algorithm.
  * <br>
  * The differences between the basic algorithm and the algorithm addressed
  * by this option are as follows:
  * <ul>
  *   <li>Within text at an even embedding level, the sequence "123AB"
  *   (where AB represent R or AL letters) is transformed to "123BA" by the
  *   Unicode algorithm and to "BA123" by the Windows algorithm.</li>
  *   <li>Arabic-Indic numbers (AN) are handled by the Windows algorithm just
  *   like regular numbers (EN).</li>
  * </ul></li>
  *
  * <li>When the reordering mode is set to
  * <code>#UBIDI_REORDER_GROUP_NUMBERS_WITH_R</code>,
  * numbers located between LTR text and RTL text are associated with the RTL
  * text. For instance, an LTR paragraph with content "abc 123 DEF" (where
  * upper case letters represent RTL characters) will be transformed to
  * "abc FED 123" (and not "abc 123 FED"), "DEF 123 abc" will be transformed
  * to "123 FED abc" and "123 FED abc" will be transformed to "DEF 123 abc".
  * This makes the algorithm reversible and makes it useful when round trip
  * (from visual to logical and back to visual) must be achieved without
  * adding LRM characters. However, this is a variation from the standard
  * Unicode Bidi algorithm.<br>
  * The source text should not contain Bidi control characters other than LRM
  * or RLM.</li>
  *
  * <li>When the reordering mode is set to
  * <code>#UBIDI_REORDER_RUNS_ONLY</code>,
  * a "Logical to Logical" transformation must be performed:
  * <ul>
  * <li>If the default text level of the source text (argument <code>paraLevel</code>
  * in <code>ubidi_setPara</code>) is even, the source text will be handled as
  * LTR logical text and will be transformed to the RTL logical text which has
  * the same LTR visual display.</li>
  * <li>If the default level of the source text is odd, the source text
  * will be handled as RTL logical text and will be transformed to the
  * LTR logical text which has the same LTR visual display.</li>
  * </ul>
  * This mode may be needed when logical text which is basically Arabic or
  * Hebrew, with possible included numbers or phrases in English, has to be
  * displayed as if it had an even embedding level (this can happen if the
  * displaying application treats all text as if it was basically LTR).
  * <br>
  * This mode may also be needed in the reverse case, when logical text which is
  * basically English, with possible included phrases in Arabic or Hebrew, has to
  * be displayed as if it had an odd embedding level.
  * <br>
  * Both cases could be handled by adding LRE or RLE at the head of the text,
  * if the display subsystem supports these formatting controls. If it does not,
  * the problem may be handled by transforming the source text in this mode
  * before displaying it, so that it will be displayed properly.<br>
  * The source text should not contain Bidi control characters other than LRM
  * or RLM.</li>
  *
  * <li>When the reordering mode is set to
  * <code>#UBIDI_REORDER_INVERSE_NUMBERS_AS_L</code>, an "inverse Bidi" algorithm
  * is applied.
  * Runs of text with numeric characters will be treated like LTR letters and
  * may need to be surrounded with LRM characters when they are written in
  * reordered sequence (the option <code>#UBIDI_INSERT_LRM_FOR_NUMERIC</code> can
  * be used with function <code>ubidi_writeReordered</code> to this end. This
  * mode is equivalent to calling <code>ubidi_setInverse()</code> with
  * argument <code>isInverse</code> set to <code>true</code>.</li>
  *
  * <li>When the reordering mode is set to
  * <code>#UBIDI_REORDER_INVERSE_LIKE_DIRECT</code>, the "direct" Logical to Visual
  * Bidi algorithm is used as an approximation of an "inverse Bidi" algorithm.
  * This mode is similar to mode <code>#UBIDI_REORDER_INVERSE_NUMBERS_AS_L</code>
  * but is closer to the regular Bidi algorithm.
  * <br>
  * For example, an LTR paragraph with the content "FED 123 456 CBA" (where
  * upper case represents RTL characters) will be transformed to
  * "ABC 456 123 DEF", as opposed to "DEF 123 456 ABC"
  * with mode <code>UBIDI_REORDER_INVERSE_NUMBERS_AS_L</code>.<br>
  * When used in conjunction with option
  * <code>#UBIDI_OPTION_INSERT_MARKS</code>, this mode generally
  * adds Bidi marks to the output significantly more sparingly than mode
  * <code>#UBIDI_REORDER_INVERSE_NUMBERS_AS_L</code> with option
  * <code>#UBIDI_INSERT_LRM_FOR_NUMERIC</code> in calls to
  * <code>ubidi_writeReordered</code>.</li>
  *
  * <li>When the reordering mode is set to
  * <code>#UBIDI_REORDER_INVERSE_FOR_NUMBERS_SPECIAL</code>, the Logical to Visual
  * Bidi algorithm used in Windows XP is used as an approximation of an "inverse Bidi" algorithm.
  * <br>
  * For example, an LTR paragraph with the content "abc FED123" (where
  * upper case represents RTL characters) will be transformed to "abc 123DEF."</li>
  * </ul>
  *
  * <p>In all the reordering modes specifying an "inverse Bidi" algorithm
  * (i.e. those with a name starting with <code>UBIDI_REORDER_INVERSE</code>),
  * output runs should be retrieved using
  * <code>ubidi_getVisualRun()</code>, and the output text with
  * <code>ubidi_writeReordered()</code>. The caller should keep in mind that in
  * "inverse Bidi" modes the input is actually visually ordered text and
  * reordered output returned by <code>ubidi_getVisualRun()</code> or
  * <code>ubidi_writeReordered()</code> are actually runs or character string
  * of logically ordered output.<br>
  * For all the "inverse Bidi" modes, the source text should not contain
  * Bidi control characters other than LRM or RLM.</p>
  *
  * <p>Note that option <code>#UBIDI_OUTPUT_REVERSE</code> of
  * <code>ubidi_writeReordered</code> has no useful meaning and should not be
  * used in conjunction with any value of the reordering mode specifying
  * "inverse Bidi" or with value <code>UBIDI_REORDER_RUNS_ONLY</code>.
  *
  * @param pBiDi is a <code>UBiDi</code> object.
  * @param reorderingMode specifies the required variant of the Bidi algorithm.
  *
  * @see UBiDiReorderingMode
  * @see ubidi_setInverse
  * @see ubidi_setPara
  * @see ubidi_writeReordered
  * @stable ICU 3.6
  */
 U_CAPI void U_EXPORT2
 ubidi_setReorderingMode(UBiDi *pBiDi, UBiDiReorderingMode reorderingMode);
 
 /**
  * What is the requested reordering mode for a given Bidi object?
  *
  * @param pBiDi is a <code>UBiDi</code> object.
  * @return the current reordering mode of the Bidi object
  * @see ubidi_setReorderingMode
  * @stable ICU 3.6
  */
 U_CAPI UBiDiReorderingMode U_EXPORT2
 ubidi_getReorderingMode(UBiDi *pBiDi);
 
 /**
  * <code>UBiDiReorderingOption</code> values indicate which options are
  * specified to affect the Bidi algorithm.
  *
  * @see ubidi_setReorderingOptions
  * @stable ICU 3.6
  */
 typedef enum UBiDiReorderingOption {
     /**
      * option value for <code>ubidi_setReorderingOptions</code>:
      * disable all the options which can be set with this function
      * @see ubidi_setReorderingOptions
      * @stable ICU 3.6
      */
     UBIDI_OPTION_DEFAULT = 0,
 
     /**
      * option bit for <code>ubidi_setReorderingOptions</code>:
      * insert Bidi marks (LRM or RLM) when needed to ensure correct result of
      * a reordering to a Logical order
      *
      * <p>This option must be set or reset before calling
      * <code>ubidi_setPara</code>.</p>
      *
      * <p>This option is significant only with reordering modes which generate
      * a result with Logical order, specifically:</p>
      * <ul>
      *   <li><code>#UBIDI_REORDER_RUNS_ONLY</code></li>
      *   <li><code>#UBIDI_REORDER_INVERSE_NUMBERS_AS_L</code></li>
      *   <li><code>#UBIDI_REORDER_INVERSE_LIKE_DIRECT</code></li>
      *   <li><code>#UBIDI_REORDER_INVERSE_FOR_NUMBERS_SPECIAL</code></li>
      * </ul>
      *
      * <p>If this option is set in conjunction with reordering mode
      * <code>#UBIDI_REORDER_INVERSE_NUMBERS_AS_L</code> or with calling
      * <code>ubidi_setInverse(true)</code>, it implies
      * option <code>#UBIDI_INSERT_LRM_FOR_NUMERIC</code>
      * in calls to function <code>ubidi_writeReordered()</code>.</p>
      *
      * <p>For other reordering modes, a minimum number of LRM or RLM characters
      * will be added to the source text after reordering it so as to ensure
      * round trip, i.e. when applying the inverse reordering mode on the
      * resulting logical text with removal of Bidi marks
      * (option <code>#UBIDI_OPTION_REMOVE_CONTROLS</code> set before calling
      * <code>ubidi_setPara()</code> or option <code>#UBIDI_REMOVE_BIDI_CONTROLS</code>
      * in <code>ubidi_writeReordered</code>), the result will be identical to the
      * source text in the first transformation.
      *
      * <p>This option will be ignored if specified together with option
      * <code>#UBIDI_OPTION_REMOVE_CONTROLS</code>. It inhibits option
      * <code>UBIDI_REMOVE_BIDI_CONTROLS</code> in calls to function
      * <code>ubidi_writeReordered()</code> and it implies option
      * <code>#UBIDI_INSERT_LRM_FOR_NUMERIC</code> in calls to function
      * <code>ubidi_writeReordered()</code> if the reordering mode is
      * <code>#UBIDI_REORDER_INVERSE_NUMBERS_AS_L</code>.</p>
      *
      * @see ubidi_setReorderingMode
      * @see ubidi_setReorderingOptions
      * @stable ICU 3.6
      */
     UBIDI_OPTION_INSERT_MARKS = 1,
 
     /**
      * option bit for <code>ubidi_setReorderingOptions</code>:
      * remove Bidi control characters
      *
      * <p>This option must be set or reset before calling
      * <code>ubidi_setPara</code>.</p>
      *
      * <p>This option nullifies option <code>#UBIDI_OPTION_INSERT_MARKS</code>.
      * It inhibits option <code>#UBIDI_INSERT_LRM_FOR_NUMERIC</code> in calls
      * to function <code>ubidi_writeReordered()</code> and it implies option
      * <code>#UBIDI_REMOVE_BIDI_CONTROLS</code> in calls to that function.</p>
      *
      * @see ubidi_setReorderingMode
      * @see ubidi_setReorderingOptions
      * @stable ICU 3.6
      */
     UBIDI_OPTION_REMOVE_CONTROLS = 2,
 
     /**
      * option bit for <code>ubidi_setReorderingOptions</code>:
      * process the output as part of a stream to be continued
      *
      * <p>This option must be set or reset before calling
      * <code>ubidi_setPara</code>.</p>
      *
      * <p>This option specifies that the caller is interested in processing large
      * text object in parts.
      * The results of the successive calls are expected to be concatenated by the
      * caller. Only the call for the last part will have this option bit off.</p>
      *
      * <p>When this option bit is on, <code>ubidi_setPara()</code> may process
      * less than the full source text in order to truncate the text at a meaningful
      * boundary. The caller should call <code>ubidi_getProcessedLength()</code>
      * immediately after calling <code>ubidi_setPara()</code> in order to
      * determine how much of the source text has been processed.
      * Source text beyond that length should be resubmitted in following calls to
      * <code>ubidi_setPara</code>. The processed length may be less than
      * the length of the source text if a character preceding the last character of
      * the source text constitutes a reasonable boundary (like a block separator)
      * for text to be continued.<br>
      * If the last character of the source text constitutes a reasonable
      * boundary, the whole text will be processed at once.<br>
      * If nowhere in the source text there exists
      * such a reasonable boundary, the processed length will be zero.<br>
      * The caller should check for such an occurrence and do one of the following:
      * <ul><li>submit a larger amount of text with a better chance to include
      *         a reasonable boundary.</li>
      *     <li>resubmit the same text after turning off option
      *         <code>UBIDI_OPTION_STREAMING</code>.</li></ul>
      * In all cases, this option should be turned off before processing the last
      * part of the text.</p>
      *
      * <p>When the <code>UBIDI_OPTION_STREAMING</code> option is used,
      * it is recommended to call <code>ubidi_orderParagraphsLTR()</code> with
      * argument <code>orderParagraphsLTR</code> set to <code>true</code> before
      * calling <code>ubidi_setPara</code> so that later paragraphs may be
      * concatenated to previous paragraphs on the right.</p>
      *
      * @see ubidi_setReorderingMode
      * @see ubidi_setReorderingOptions
      * @see ubidi_getProcessedLength
      * @see ubidi_orderParagraphsLTR
      * @stable ICU 3.6
      */
     UBIDI_OPTION_STREAMING = 4
 } UBiDiReorderingOption;
 
 /**
  * Specify which of the reordering options
  * should be applied during Bidi transformations.
  *
  * @param pBiDi is a <code>UBiDi</code> object.
  * @param reorderingOptions is a combination of zero or more of the following
  * options:
  * <code>#UBIDI_OPTION_DEFAULT</code>, <code>#UBIDI_OPTION_INSERT_MARKS</code>,
  * <code>#UBIDI_OPTION_REMOVE_CONTROLS</code>, <code>#UBIDI_OPTION_STREAMING</code>.
  *
  * @see ubidi_getReorderingOptions
  * @stable ICU 3.6
  */
 U_CAPI void U_EXPORT2
 ubidi_setReorderingOptions(UBiDi *pBiDi, uint32_t reorderingOptions);
 
 /**
  * What are the reordering options applied to a given Bidi object?
  *
  * @param pBiDi is a <code>UBiDi</code> object.
  * @return the current reordering options of the Bidi object
  * @see ubidi_setReorderingOptions
  * @stable ICU 3.6
  */
 U_CAPI uint32_t U_EXPORT2
 ubidi_getReorderingOptions(UBiDi *pBiDi);
 
 /**
  * Set the context before a call to ubidi_setPara().<p>
  *
  * ubidi_setPara() computes the left-right directionality for a given piece
  * of text which is supplied as one of its arguments. Sometimes this piece
  * of text (the "main text") should be considered in context, because text
  * appearing before ("prologue") and/or after ("epilogue") the main text
  * may affect the result of this computation.<p>
  *
  * This function specifies the prologue and/or the epilogue for the next
  * call to ubidi_setPara(). The characters specified as prologue and
  * epilogue should not be modified by the calling program until the call
  * to ubidi_setPara() has returned. If successive calls to ubidi_setPara()
  * all need specification of a context, ubidi_setContext() must be called
  * before each call to ubidi_setPara(). In other words, a context is not
  * "remembered" after the following successful call to ubidi_setPara().<p>
  *
  * If a call to ubidi_setPara() specifies UBIDI_DEFAULT_LTR or
  * UBIDI_DEFAULT_RTL as paraLevel and is preceded by a call to
  * ubidi_setContext() which specifies a prologue, the paragraph level will
  * be computed taking in consideration the text in the prologue.<p>
  *
  * When ubidi_setPara() is called without a previous call to
  * ubidi_setContext, the main text is handled as if preceded and followed
  * by strong directional characters at the current paragraph level.
  * Calling ubidi_setContext() with specification of a prologue will change
  * this behavior by handling the main text as if preceded by the last
  * strong character appearing in the prologue, if any.
  * Calling ubidi_setContext() with specification of an epilogue will change
  * the behavior of ubidi_setPara() by handling the main text as if followed
  * by the first strong character or digit appearing in the epilogue, if any.<p>
  *
  * Note 1: if <code>ubidi_setContext</code> is called repeatedly without
  *         calling <code>ubidi_setPara</code>, the earlier calls have no effect,
  *         only the last call will be remembered for the next call to
  *         <code>ubidi_setPara</code>.<p>
  *
  * Note 2: calling <code>ubidi_setContext(pBiDi, NULL, 0, NULL, 0, &errorCode)</code>
  *         cancels any previous setting of non-empty prologue or epilogue.
  *         The next call to <code>ubidi_setPara()</code> will process no
  *         prologue or epilogue.<p>
  *
  * Note 3: users must be aware that even after setting the context
  *         before a call to ubidi_setPara() to perform e.g. a logical to visual
  *         transformation, the resulting string may not be identical to what it
  *         would have been if all the text, including prologue and epilogue, had
  *         been processed together.<br>
  * Example (upper case letters represent RTL characters):<br>
  * &nbsp;&nbsp;prologue = "<code>abc DE</code>"<br>
  * &nbsp;&nbsp;epilogue = none<br>
  * &nbsp;&nbsp;main text = "<code>FGH xyz</code>"<br>
  * &nbsp;&nbsp;paraLevel = UBIDI_LTR<br>
  * &nbsp;&nbsp;display without prologue = "<code>HGF xyz</code>"
  *             ("HGF" is adjacent to "xyz")<br>
  * &nbsp;&nbsp;display with prologue = "<code>abc HGFED xyz</code>"
  *             ("HGF" is not adjacent to "xyz")<br>
  *
  * @param pBiDi is a paragraph <code>UBiDi</code> object.
  *
  * @param prologue is a pointer to the text which precedes the text that
  *        will be specified in a coming call to ubidi_setPara().
  *        If there is no prologue to consider, then <code>proLength</code>
  *        must be zero and this pointer can be NULL.
  *
  * @param proLength is the length of the prologue; if <code>proLength==-1</code>
  *        then the prologue must be zero-terminated.
  *        Otherwise proLength must be >= 0. If <code>proLength==0</code>, it means
  *        that there is no prologue to consider.
  *
  * @param epilogue is a pointer to the text which follows the text that
  *        will be specified in a coming call to ubidi_setPara().
  *        If there is no epilogue to consider, then <code>epiLength</code>
  *        must be zero and this pointer can be NULL.
  *
  * @param epiLength is the length of the epilogue; if <code>epiLength==-1</code>
  *        then the epilogue must be zero-terminated.
  *        Otherwise epiLength must be >= 0. If <code>epiLength==0</code>, it means
  *        that there is no epilogue to consider.
  *
  * @param pErrorCode must be a valid pointer to an error code value.
  *
  * @see ubidi_setPara
  * @stable ICU 4.8
  */
 U_CAPI void U_EXPORT2
 ubidi_setContext(UBiDi *pBiDi,
                  const UChar *prologue, int32_t proLength,
                  const UChar *epilogue, int32_t epiLength,
                  UErrorCode *pErrorCode);
 
 /**
  * Perform the Unicode Bidi algorithm. It is defined in the
  * <a href="http://www.unicode.org/unicode/reports/tr9/">Unicode Standard Annex #9</a>,
  * version 13,
  * also described in The Unicode Standard, Version 4.0 .<p>
  *
  * This function takes a piece of plain text containing one or more paragraphs,
  * with or without externally specified embedding levels from <i>styled</i>
  * text and computes the left-right-directionality of each character.<p>
  *
  * If the entire text is all of the same directionality, then
  * the function may not perform all the steps described by the algorithm,
  * i.e., some levels may not be the same as if all steps were performed.
  * This is not relevant for unidirectional text.<br>
  * For example, in pure LTR text with numbers the numbers would get
  * a resolved level of 2 higher than the surrounding text according to
  * the algorithm. This implementation may set all resolved levels to
  * the same value in such a case.<p>
  *
  * The text can be composed of multiple paragraphs. Occurrence of a block
  * separator in the text terminates a paragraph, and whatever comes next starts
  * a new paragraph. The exception to this rule is when a Carriage Return (CR)
  * is followed by a Line Feed (LF). Both CR and LF are block separators, but
  * in that case, the pair of characters is considered as terminating the
  * preceding paragraph, and a new paragraph will be started by a character
  * coming after the LF.
  *
  * @param pBiDi A <code>UBiDi</code> object allocated with <code>ubidi_open()</code>
  *        which will be set to contain the reordering information,
  *        especially the resolved levels for all the characters in <code>text</code>.
  *
  * @param text is a pointer to the text that the Bidi algorithm will be performed on.
  *        This pointer is stored in the UBiDi object and can be retrieved
  *        with <code>ubidi_getText()</code>.<br>
  *        <strong>Note:</strong> the text must be (at least) <code>length</code> long.
  *
  * @param length is the length of the text; if <code>length==-1</code> then
  *        the text must be zero-terminated.
  *
  * @param paraLevel specifies the default level for the text;
  *        it is typically 0 (LTR) or 1 (RTL).
  *        If the function shall determine the paragraph level from the text,
  *        then <code>paraLevel</code> can be set to
  *        either <code>#UBIDI_DEFAULT_LTR</code>
  *        or <code>#UBIDI_DEFAULT_RTL</code>; if the text contains multiple
  *        paragraphs, the paragraph level shall be determined separately for
  *        each paragraph; if a paragraph does not include any strongly typed
  *        character, then the desired default is used (0 for LTR or 1 for RTL).
  *        Any other value between 0 and <code>#UBIDI_MAX_EXPLICIT_LEVEL</code>
  *        is also valid, with odd levels indicating RTL.
  *
  * @param embeddingLevels (in) may be used to preset the embedding and override levels,
  *        ignoring characters like LRE and PDF in the text.
  *        A level overrides the directional property of its corresponding
  *        (same index) character if the level has the
  *        <code>#UBIDI_LEVEL_OVERRIDE</code> bit set.<br><br>
  *        Aside from that bit, it must be
  *        <code>paraLevel<=embeddingLevels[]<=UBIDI_MAX_EXPLICIT_LEVEL</code>,
  *        except that level 0 is always allowed.
  *        Level 0 for a paragraph separator prevents reordering of paragraphs;
  *        this only works reliably if <code>#UBIDI_LEVEL_OVERRIDE</code>
  *        is also set for paragraph separators.
  *        Level 0 for other characters is treated as a wildcard
  *        and is lifted up to the resolved level of the surrounding paragraph.<br><br>
  *        <strong>Caution: </strong>A copy of this pointer, not of the levels,
  *        will be stored in the <code>UBiDi</code> object;
  *        the <code>embeddingLevels</code> array must not be
  *        deallocated before the <code>UBiDi</code> structure is destroyed or reused,
  *        and the <code>embeddingLevels</code>
  *        should not be modified to avoid unexpected results on subsequent Bidi operations.
  *        However, the <code>ubidi_setPara()</code> and
  *        <code>ubidi_setLine()</code> functions may modify some or all of the levels.<br><br>
  *        After the <code>UBiDi</code> object is reused or destroyed, the caller
  *        must take care of the deallocation of the <code>embeddingLevels</code> array.<br><br>
  *        <strong>Note:</strong> the <code>embeddingLevels</code> array must be
  *        at least <code>length</code> long.
  *        This pointer can be <code>NULL</code> if this
  *        value is not necessary.
  *
  * @param pErrorCode must be a valid pointer to an error code value.
  * @stable ICU 2.0
  */
 U_CAPI void U_EXPORT2
 ubidi_setPara(UBiDi *pBiDi, const UChar *text, int32_t length,
               UBiDiLevel paraLevel, UBiDiLevel *embeddingLevels,
               UErrorCode *pErrorCode);
 
 /**
  * <code>ubidi_setLine()</code> sets a <code>UBiDi</code> to
  * contain the reordering information, especially the resolved levels,
  * for all the characters in a line of text. This line of text is
  * specified by referring to a <code>UBiDi</code> object representing
  * this information for a piece of text containing one or more paragraphs,
  * and by specifying a range of indexes in this text.<p>
  * In the new line object, the indexes will range from 0 to <code>limit-start-1</code>.<p>
  *
  * This is used after calling <code>ubidi_setPara()</code>
  * for a piece of text, and after line-breaking on that text.
  * It is not necessary if each paragraph is treated as a single line.<p>
  *
  * After line-breaking, rules (L1) and (L2) for the treatment of
  * trailing WS and for reordering are performed on
  * a <code>UBiDi</code> object that represents a line.<p>
  *
  * <strong>Important: </strong><code>pLineBiDi</code> shares data with
  * <code>pParaBiDi</code>.
  * You must destroy or reuse <code>pLineBiDi</code> before <code>pParaBiDi</code>.
  * In other words, you must destroy or reuse the <code>UBiDi</code> object for a line
  * before the object for its parent paragraph.<p>
  *
  * The text pointer that was stored in <code>pParaBiDi</code> is also copied,
  * and <code>start</code> is added to it so that it points to the beginning of the
  * line for this object.
  *
  * @param pParaBiDi is the parent paragraph object. It must have been set
  * by a successful call to ubidi_setPara.
  *
  * @param start is the line's first index into the text.
  *
  * @param limit is just behind the line's last index into the text
  *        (its last index +1).<br>
  *        It must be <code>0<=start<limit<=</code>containing paragraph limit.
  *        If the specified line crosses a paragraph boundary, the function
  *        will terminate with error code U_ILLEGAL_ARGUMENT_ERROR.
  *
  * @param pLineBiDi is the object that will now represent a line of the text.
  *
  * @param pErrorCode must be a valid pointer to an error code value.
  *
  * @see ubidi_setPara
  * @see ubidi_getProcessedLength
  * @stable ICU 2.0
  */
 U_CAPI void U_EXPORT2
 ubidi_setLine(const UBiDi *pParaBiDi,
               int32_t start, int32_t limit,
               UBiDi *pLineBiDi,
               UErrorCode *pErrorCode);
 
 /**
  * Get the directionality of the text.
  *
  * @param pBiDi is the paragraph or line <code>UBiDi</code> object.
  *
  * @return a value of <code>UBIDI_LTR</code>, <code>UBIDI_RTL</code>
  *         or <code>UBIDI_MIXED</code>
  *         that indicates if the entire text
  *         represented by this object is unidirectional,
  *         and which direction, or if it is mixed-directional.
  * Note -  The value <code>UBIDI_NEUTRAL</code> is never returned from this method.
  *
  * @see UBiDiDirection
  * @stable ICU 2.0
  */
 U_CAPI UBiDiDirection U_EXPORT2
 ubidi_getDirection(const UBiDi *pBiDi);
 
 /**
  * Gets the base direction of the text provided according
  * to the Unicode Bidirectional Algorithm. The base direction
  * is derived from the first character in the string with bidirectional
  * character type L, R, or AL. If the first such character has type L,
  * <code>UBIDI_LTR</code> is returned. If the first such character has
  * type R or AL, <code>UBIDI_RTL</code> is returned. If the string does
  * not contain any character of these types, then
  * <code>UBIDI_NEUTRAL</code> is returned.
  *
  * This is a lightweight function for use when only the base direction
  * is needed and no further bidi processing of the text is needed.
  *
  * @param text is a pointer to the text whose base
  *             direction is needed.
  * Note: the text must be (at least) @c length long.
  *
  * @param length is the length of the text;
  *               if <code>length==-1</code> then the text
  *               must be zero-terminated.
  *
  * @return  <code>UBIDI_LTR</code>, <code>UBIDI_RTL</code>,
  *          <code>UBIDI_NEUTRAL</code>
  *
  * @see UBiDiDirection
  * @stable ICU 4.6
  */
 U_CAPI UBiDiDirection U_EXPORT2
 ubidi_getBaseDirection(const UChar *text,  int32_t length );
 
 /**
  * Get the pointer to the text.
  *
  * @param pBiDi is the paragraph or line <code>UBiDi</code> object.
  *
  * @return The pointer to the text that the UBiDi object was created for.
  *
  * @see ubidi_setPara
  * @see ubidi_setLine
  * @stable ICU 2.0
  */
 U_CAPI const UChar * U_EXPORT2
 ubidi_getText(const UBiDi *pBiDi);
 
 /**
  * Get the length of the text.
  *
  * @param pBiDi is the paragraph or line <code>UBiDi</code> object.
  *
  * @return The length of the text that the UBiDi object was created for.
  * @stable ICU 2.0
  */
 U_CAPI int32_t U_EXPORT2
 ubidi_getLength(const UBiDi *pBiDi);
 
 /**
  * Get the paragraph level of the text.
  *
  * @param pBiDi is the paragraph or line <code>UBiDi</code> object.
  *
  * @return The paragraph level. If there are multiple paragraphs, their
  *         level may vary if the required paraLevel is UBIDI_DEFAULT_LTR or
  *         UBIDI_DEFAULT_RTL.  In that case, the level of the first paragraph
  *         is returned.
  *
  * @see UBiDiLevel
  * @see ubidi_getParagraph
  * @see ubidi_getParagraphByIndex
  * @stable ICU 2.0
  */
 U_CAPI UBiDiLevel U_EXPORT2
 ubidi_getParaLevel(const UBiDi *pBiDi);
 
 /**
  * Get the number of paragraphs.
  *
  * @param pBiDi is the paragraph or line <code>UBiDi</code> object.
  *
  * @return The number of paragraphs.
  * @stable ICU 3.4
  */
 U_CAPI int32_t U_EXPORT2
 ubidi_countParagraphs(UBiDi *pBiDi);
 
 /**
  * Get a paragraph, given a position within the text.
  * This function returns information about a paragraph.<br>
  * Note: if the paragraph index is known, it is more efficient to
  * retrieve the paragraph information using ubidi_getParagraphByIndex().<p>
  *
  * @param pBiDi is the paragraph or line <code>UBiDi</code> object.
  *
  * @param charIndex is the index of a character within the text, in the
  *        range <code>[0..ubidi_getProcessedLength(pBiDi)-1]</code>.
  *
  * @param pParaStart will receive the index of the first character of the
  *        paragraph in the text.
  *        This pointer can be <code>NULL</code> if this
  *        value is not necessary.
  *
  * @param pParaLimit will receive the limit of the paragraph.
  *        The l-value that you point to here may be the
  *        same expression (variable) as the one for
  *        <code>charIndex</code>.
  *        This pointer can be <code>NULL</code> if this
  *        value is not necessary.
  *
  * @param pParaLevel will receive the level of the paragraph.
  *        This pointer can be <code>NULL</code> if this
  *        value is not necessary.
  *
  * @param pErrorCode must be a valid pointer to an error code value.
  *
  * @return The index of the paragraph containing the specified position.
  *
  * @see ubidi_getProcessedLength
  * @stable ICU 3.4
  */
 U_CAPI int32_t U_EXPORT2
 ubidi_getParagraph(const UBiDi *pBiDi, int32_t charIndex, int32_t *pParaStart,
                    int32_t *pParaLimit, UBiDiLevel *pParaLevel,
                    UErrorCode *pErrorCode);
 
 /**
  * Get a paragraph, given the index of this paragraph.
  *
  * This function returns information about a paragraph.<p>
  *
  * @param pBiDi is the paragraph <code>UBiDi</code> object.
  *
  * @param paraIndex is the number of the paragraph, in the
  *        range <code>[0..ubidi_countParagraphs(pBiDi)-1]</code>.
  *
  * @param pParaStart will receive the index of the first character of the
  *        paragraph in the text.
  *        This pointer can be <code>NULL</code> if this
  *        value is not necessary.
  *
  * @param pParaLimit will receive the limit of the paragraph.
  *        This pointer can be <code>NULL</code> if this
  *        value is not necessary.
  *
  * @param pParaLevel will receive the level of the paragraph.
  *        This pointer can be <code>NULL</code> if this
  *        value is not necessary.
  *
  * @param pErrorCode must be a valid pointer to an error code value.
  *
  * @stable ICU 3.4
  */
 U_CAPI void U_EXPORT2
 ubidi_getParagraphByIndex(const UBiDi *pBiDi, int32_t paraIndex,
                           int32_t *pParaStart, int32_t *pParaLimit,
                           UBiDiLevel *pParaLevel, UErrorCode *pErrorCode);
 
 /**
  * Get the level for one character.
  *
  * @param pBiDi is the paragraph or line <code>UBiDi</code> object.
  *
  * @param charIndex the index of a character. It must be in the range
  *         [0..ubidi_getProcessedLength(pBiDi)].
  *
  * @return The level for the character at charIndex (0 if charIndex is not
  *         in the valid range).
  *
  * @see UBiDiLevel
  * @see ubidi_getProcessedLength
  * @stable ICU 2.0
  */
 U_CAPI UBiDiLevel U_EXPORT2
 ubidi_getLevelAt(const UBiDi *pBiDi, int32_t charIndex);
 
 /**
  * Get an array of levels for each character.<p>
  *
  * Note that this function may allocate memory under some
  * circumstances, unlike <code>ubidi_getLevelAt()</code>.
  *
  * @param pBiDi is the paragraph or line <code>UBiDi</code> object, whose
  *        text length must be strictly positive.
  *
  * @param pErrorCode must be a valid pointer to an error code value.
  *
  * @return The levels array for the text,
  *         or <code>NULL</code> if an error occurs.
  *
  * @see UBiDiLevel
  * @see ubidi_getProcessedLength
  * @stable ICU 2.0
  */
 U_CAPI const UBiDiLevel * U_EXPORT2
 ubidi_getLevels(UBiDi *pBiDi, UErrorCode *pErrorCode);
 
 /**
  * Get a logical run.
  * This function returns information about a run and is used
  * to retrieve runs in logical order.<p>
  * This is especially useful for line-breaking on a paragraph.
  *
  * @param pBiDi is the paragraph or line <code>UBiDi</code> object.
  *
  * @param logicalPosition is a logical position within the source text.
  *
  * @param pLogicalLimit will receive the limit of the corresponding run.
  *        The l-value that you point to here may be the
  *        same expression (variable) as the one for
  *        <code>logicalPosition</code>.
  *        This pointer can be <code>NULL</code> if this
  *        value is not necessary.
  *
  * @param pLevel will receive the level of the corresponding run.
  *        This pointer can be <code>NULL</code> if this
  *        value is not necessary.
  *
  * @see ubidi_getProcessedLength
  * @stable ICU 2.0
  */
 U_CAPI void U_EXPORT2
 ubidi_getLogicalRun(const UBiDi *pBiDi, int32_t logicalPosition,
                     int32_t *pLogicalLimit, UBiDiLevel *pLevel);
 
 /**
  * Get the number of runs.
  * This function may invoke the actual reordering on the
  * <code>UBiDi</code> object, after <code>ubidi_setPara()</code>
  * may have resolved only the levels of the text. Therefore,
  * <code>ubidi_countRuns()</code> may have to allocate memory,
  * and may fail doing so.
  *
  * @param pBiDi is the paragraph or line <code>UBiDi</code> object.
  *
  * @param pErrorCode must be a valid pointer to an error code value.
  *
  * @return The number of runs.
  * @stable ICU 2.0
  */
 U_CAPI int32_t U_EXPORT2
 ubidi_countRuns(UBiDi *pBiDi, UErrorCode *pErrorCode);
 
 /**
  * Get one run's logical start, length, and directionality,
  * which can be 0 for LTR or 1 for RTL.
  * In an RTL run, the character at the logical start is
  * visually on the right of the displayed run.
  * The length is the number of characters in the run.<p>
  * <code>ubidi_countRuns()</code> should be called
  * before the runs are retrieved.
  *
  * @param pBiDi is the paragraph or line <code>UBiDi</code> object.
  *
  * @param runIndex is the number of the run in visual order, in the
  *        range <code>[0..ubidi_countRuns(pBiDi)-1]</code>.
  *
  * @param pLogicalStart is the first logical character index in the text.
  *        The pointer may be <code>NULL</code> if this index is not needed.
  *
  * @param pLength is the number of characters (at least one) in the run.
  *        The pointer may be <code>NULL</code> if this is not needed.
  *
  * @return the directionality of the run,
  *         <code>UBIDI_LTR==0</code> or <code>UBIDI_RTL==1</code>,
  *         never <code>UBIDI_MIXED</code>,
  *         never <code>UBIDI_NEUTRAL</code>.
  *
  * @see ubidi_countRuns
  *
  * Example:
  * <pre>
  * \code
  * int32_t i, count=ubidi_countRuns(pBiDi),
  *         logicalStart, visualIndex=0, length;
  * for(i=0; i<count; ++i) {
  *    if(UBIDI_LTR==ubidi_getVisualRun(pBiDi, i, &logicalStart, &length)) {
  *         do { // LTR
  *             show_char(text[logicalStart++], visualIndex++);
  *         } while(--length>0);
  *     } else {
  *         logicalStart+=length;  // logicalLimit
  *         do { // RTL
  *             show_char(text[--logicalStart], visualIndex++);
  *         } while(--length>0);
  *     }
  * }
  *\endcode
  * </pre>
  *
  * Note that in right-to-left runs, code like this places
  * second surrogates before first ones (which is generally a bad idea)
  * and combining characters before base characters.
  * <p>
  * Use of <code>ubidi_writeReordered()</code>, optionally with the
  * <code>#UBIDI_KEEP_BASE_COMBINING</code> option, can be considered in order
  * to avoid these issues.
  * @stable ICU 2.0
  */
 U_CAPI UBiDiDirection U_EXPORT2
 ubidi_getVisualRun(UBiDi *pBiDi, int32_t runIndex,
                    int32_t *pLogicalStart, int32_t *pLength);
 
 /**
  * Get the visual position from a logical text position.
  * If such a mapping is used many times on the same
  * <code>UBiDi</code> object, then calling
  * <code>ubidi_getLogicalMap()</code> is more efficient.<p>
  *
  * The value returned may be <code>#UBIDI_MAP_NOWHERE</code> if there is no
  * visual position because the corresponding text character is a Bidi control
  * removed from output by the option <code>#UBIDI_OPTION_REMOVE_CONTROLS</code>.
  * <p>
  * When the visual output is altered by using options of
  * <code>ubidi_writeReordered()</code> such as <code>UBIDI_INSERT_LRM_FOR_NUMERIC</code>,
  * <code>UBIDI_KEEP_BASE_COMBINING</code>, <code>UBIDI_OUTPUT_REVERSE</code>,
  * <code>UBIDI_REMOVE_BIDI_CONTROLS</code>, the visual position returned may not
  * be correct. It is advised to use, when possible, reordering options
  * such as <code>UBIDI_OPTION_INSERT_MARKS</code> and <code>UBIDI_OPTION_REMOVE_CONTROLS</code>.
  * <p>
  * Note that in right-to-left runs, this mapping places
  * second surrogates before first ones (which is generally a bad idea)
  * and combining characters before base characters.
  * Use of <code>ubidi_writeReordered()</code>, optionally with the
  * <code>#UBIDI_KEEP_BASE_COMBINING</code> option can be considered instead
  * of using the mapping, in order to avoid these issues.
  *
  * @param pBiDi is the paragraph or line <code>UBiDi</code> object.
  *
  * @param logicalIndex is the index of a character in the text.
  *
  * @param pErrorCode must be a valid pointer to an error code value.
  *
  * @return The visual position of this character.
  *
  * @see ubidi_getLogicalMap
  * @see ubidi_getLogicalIndex
  * @see ubidi_getProcessedLength
  * @stable ICU 2.0
  */
 U_CAPI int32_t U_EXPORT2
 ubidi_getVisualIndex(UBiDi *pBiDi, int32_t logicalIndex, UErrorCode *pErrorCode);
 
 /**
  * Get the logical text position from a visual position.
  * If such a mapping is used many times on the same
  * <code>UBiDi</code> object, then calling
  * <code>ubidi_getVisualMap()</code> is more efficient.<p>
  *
  * The value returned may be <code>#UBIDI_MAP_NOWHERE</code> if there is no
  * logical position because the corresponding text character is a Bidi mark
  * inserted in the output by option <code>#UBIDI_OPTION_INSERT_MARKS</code>.
  * <p>
  * This is the inverse function to <code>ubidi_getVisualIndex()</code>.
  * <p>
  * When the visual output is altered by using options of
  * <code>ubidi_writeReordered()</code> such as <code>UBIDI_INSERT_LRM_FOR_NUMERIC</code>,
  * <code>UBIDI_KEEP_BASE_COMBINING</code>, <code>UBIDI_OUTPUT_REVERSE</code>,
  * <code>UBIDI_REMOVE_BIDI_CONTROLS</code>, the logical position returned may not
  * be correct. It is advised to use, when possible, reordering options
  * such as <code>UBIDI_OPTION_INSERT_MARKS</code> and <code>UBIDI_OPTION_REMOVE_CONTROLS</code>.
  *
  * @param pBiDi is the paragraph or line <code>UBiDi</code> object.
  *
  * @param visualIndex is the visual position of a character.
  *
  * @param pErrorCode must be a valid pointer to an error code value.
  *
  * @return The index of this character in the text.
  *
  * @see ubidi_getVisualMap
  * @see ubidi_getVisualIndex
  * @see ubidi_getResultLength
  * @stable ICU 2.0
  */
 U_CAPI int32_t U_EXPORT2
 ubidi_getLogicalIndex(UBiDi *pBiDi, int32_t visualIndex, UErrorCode *pErrorCode);
 
 /**
  * Get a logical-to-visual index map (array) for the characters in the UBiDi
  * (paragraph or line) object.
  * <p>
  * Some values in the map may be <code>#UBIDI_MAP_NOWHERE</code> if the
  * corresponding text characters are Bidi controls removed from the visual
  * output by the option <code>#UBIDI_OPTION_REMOVE_CONTROLS</code>.
  * <p>
  * When the visual output is altered by using options of
  * <code>ubidi_writeReordered()</code> such as <code>UBIDI_INSERT_LRM_FOR_NUMERIC</code>,
  * <code>UBIDI_KEEP_BASE_COMBINING</code>, <code>UBIDI_OUTPUT_REVERSE</code>,
  * <code>UBIDI_REMOVE_BIDI_CONTROLS</code>, the visual positions returned may not
  * be correct. It is advised to use, when possible, reordering options
  * such as <code>UBIDI_OPTION_INSERT_MARKS</code> and <code>UBIDI_OPTION_REMOVE_CONTROLS</code>.
  * <p>
  * Note that in right-to-left runs, this mapping places
  * second surrogates before first ones (which is generally a bad idea)
  * and combining characters before base characters.
  * Use of <code>ubidi_writeReordered()</code>, optionally with the
  * <code>#UBIDI_KEEP_BASE_COMBINING</code> option can be considered instead
  * of using the mapping, in order to avoid these issues.
  *
  * @param pBiDi is the paragraph or line <code>UBiDi</code> object.
  *
  * @param indexMap is a pointer to an array of <code>ubidi_getProcessedLength()</code>
  *        indexes which will reflect the reordering of the characters.
  *        If option <code>#UBIDI_OPTION_INSERT_MARKS</code> is set, the number
  *        of elements allocated in <code>indexMap</code> must be no less than
  *        <code>ubidi_getResultLength()</code>.
  *        The array does not need to be initialized.<br><br>
  *        The index map will result in <code>indexMap[logicalIndex]==visualIndex</code>.
  *
  * @param pErrorCode must be a valid pointer to an error code value.
  *
  * @see ubidi_getVisualMap
  * @see ubidi_getVisualIndex
  * @see ubidi_getProcessedLength
  * @see ubidi_getResultLength
  * @stable ICU 2.0
  */
 U_CAPI void U_EXPORT2
 ubidi_getLogicalMap(UBiDi *pBiDi, int32_t *indexMap, UErrorCode *pErrorCode);
 
 /**
  * Get a visual-to-logical index map (array) for the characters in the UBiDi
  * (paragraph or line) object.
  * <p>
  * Some values in the map may be <code>#UBIDI_MAP_NOWHERE</code> if the
  * corresponding text characters are Bidi marks inserted in the visual output
  * by the option <code>#UBIDI_OPTION_INSERT_MARKS</code>.
  * <p>
  * When the visual output is altered by using options of
  * <code>ubidi_writeReordered()</code> such as <code>UBIDI_INSERT_LRM_FOR_NUMERIC</code>,
  * <code>UBIDI_KEEP_BASE_COMBINING</code>, <code>UBIDI_OUTPUT_REVERSE</code>,
  * <code>UBIDI_REMOVE_BIDI_CONTROLS</code>, the logical positions returned may not
  * be correct. It is advised to use, when possible, reordering options
  * such as <code>UBIDI_OPTION_INSERT_MARKS</code> and <code>UBIDI_OPTION_REMOVE_CONTROLS</code>.
  *
  * @param pBiDi is the paragraph or line <code>UBiDi</code> object.
  *
  * @param indexMap is a pointer to an array of <code>ubidi_getResultLength()</code>
  *        indexes which will reflect the reordering of the characters.
  *        If option <code>#UBIDI_OPTION_REMOVE_CONTROLS</code> is set, the number
  *        of elements allocated in <code>indexMap</code> must be no less than
  *        <code>ubidi_getProcessedLength()</code>.
  *        The array does not need to be initialized.<br><br>
  *        The index map will result in <code>indexMap[visualIndex]==logicalIndex</code>.
  *
  * @param pErrorCode must be a valid pointer to an error code value.
  *
  * @see ubidi_getLogicalMap
  * @see ubidi_getLogicalIndex
  * @see ubidi_getProcessedLength
  * @see ubidi_getResultLength
  * @stable ICU 2.0
  */
 U_CAPI void U_EXPORT2
 ubidi_getVisualMap(UBiDi *pBiDi, int32_t *indexMap, UErrorCode *pErrorCode);
 
 /**
  * This is a convenience function that does not use a UBiDi object.
  * It is intended to be used for when an application has determined the levels
  * of objects (character sequences) and just needs to have them reordered (L2).
  * This is equivalent to using <code>ubidi_getLogicalMap()</code> on a
  * <code>UBiDi</code> object.
  *
  * @param levels is an array with <code>length</code> levels that have been determined by
  *        the application.
  *
  * @param length is the number of levels in the array, or, semantically,
  *        the number of objects to be reordered.
  *        It must be <code>length>0</code>.
  *
  * @param indexMap is a pointer to an array of <code>length</code>
  *        indexes which will reflect the reordering of the characters.
  *        The array does not need to be initialized.<p>
  *        The index map will result in <code>indexMap[logicalIndex]==visualIndex</code>.
  * @stable ICU 2.0
  */
 U_CAPI void U_EXPORT2
 ubidi_reorderLogical(const UBiDiLevel *levels, int32_t length, int32_t *indexMap);
 
 /**
  * This is a convenience function that does not use a UBiDi object.
  * It is intended to be used for when an application has determined the levels
  * of objects (character sequences) and just needs to have them reordered (L2).
  * This is equivalent to using <code>ubidi_getVisualMap()</code> on a
  * <code>UBiDi</code> object.
  *
  * @param levels is an array with <code>length</code> levels that have been determined by
  *        the application.
  *
  * @param length is the number of levels in the array, or, semantically,
  *        the number of objects to be reordered.
  *        It must be <code>length>0</code>.
  *
  * @param indexMap is a pointer to an array of <code>length</code>
  *        indexes which will reflect the reordering of the characters.
  *        The array does not need to be initialized.<p>
  *        The index map will result in <code>indexMap[visualIndex]==logicalIndex</code>.
  * @stable ICU 2.0
  */
 U_CAPI void U_EXPORT2
 ubidi_reorderVisual(const UBiDiLevel *levels, int32_t length, int32_t *indexMap);
 
 /**
  * Invert an index map.
  * The index mapping of the first map is inverted and written to
  * the second one.
  *
  * @param srcMap is an array with <code>length</code> elements
  *        which defines the original mapping from a source array containing
  *        <code>length</code> elements to a destination array.
  *        Some elements of the source array may have no mapping in the
  *        destination array. In that case, their value will be
  *        the special value <code>UBIDI_MAP_NOWHERE</code>.
  *        All elements must be >=0 or equal to <code>UBIDI_MAP_NOWHERE</code>.
  *        Some elements may have a value >= <code>length</code>, if the
  *        destination array has more elements than the source array.
  *        There must be no duplicate indexes (two or more elements with the
  *        same value except <code>UBIDI_MAP_NOWHERE</code>).
  *
  * @param destMap is an array with a number of elements equal to 1 + the highest
  *        value in <code>srcMap</code>.
  *        <code>destMap</code> will be filled with the inverse mapping.
  *        If element with index i in <code>srcMap</code> has a value k different
  *        from <code>UBIDI_MAP_NOWHERE</code>, this means that element i of
  *        the source array maps to element k in the destination array.
  *        The inverse map will have value i in its k-th element.
  *        For all elements of the destination array which do not map to
  *        an element in the source array, the corresponding element in the
  *        inverse map will have a value equal to <code>UBIDI_MAP_NOWHERE</code>.
  *
  * @param length is the length of each array.
  * @see UBIDI_MAP_NOWHERE
  * @stable ICU 2.0
  */
 U_CAPI void U_EXPORT2
 ubidi_invertMap(const int32_t *srcMap, int32_t *destMap, int32_t length);
 
 /** option flags for ubidi_writeReordered() */
 
 /**
  * option bit for ubidi_writeReordered():
  * keep combining characters after their base characters in RTL runs
  *
  * @see ubidi_writeReordered
  * @stable ICU 2.0
  */
 #define UBIDI_KEEP_BASE_COMBINING       1
 
 /**
  * option bit for ubidi_writeReordered():
  * replace characters with the "mirrored" property in RTL runs
  * by their mirror-image mappings
  *
  * @see ubidi_writeReordered
  * @stable ICU 2.0
  */
 #define UBIDI_DO_MIRRORING              2
 
 /**
  * option bit for ubidi_writeReordered():
  * surround the run with LRMs if necessary;
  * this is part of the approximate "inverse Bidi" algorithm
  *
  * <p>This option does not imply corresponding adjustment of the index
  * mappings.</p>
  *
  * @see ubidi_setInverse
  * @see ubidi_writeReordered
  * @stable ICU 2.0
  */
 #define UBIDI_INSERT_LRM_FOR_NUMERIC    4
 
 /**
  * option bit for ubidi_writeReordered():
  * remove Bidi control characters
  * (this does not affect #UBIDI_INSERT_LRM_FOR_NUMERIC)
  *
  * <p>This option does not imply corresponding adjustment of the index
  * mappings.</p>
  *
  * @see ubidi_writeReordered
  * @stable ICU 2.0
  */
 #define UBIDI_REMOVE_BIDI_CONTROLS      8
 
 /**
  * option bit for ubidi_writeReordered():
  * write the output in reverse order
  *
  * <p>This has the same effect as calling <code>ubidi_writeReordered()</code>
  * first without this option, and then calling
  * <code>ubidi_writeReverse()</code> without mirroring.
  * Doing this in the same step is faster and avoids a temporary buffer.
  * An example for using this option is output to a character terminal that
  * is designed for RTL scripts and stores text in reverse order.</p>
  *
  * @see ubidi_writeReordered
  * @stable ICU 2.0
  */
 #define UBIDI_OUTPUT_REVERSE            16
 
 /**
  * Get the length of the source text processed by the last call to
  * <code>ubidi_setPara()</code>. This length may be different from the length
  * of the source text if option <code>#UBIDI_OPTION_STREAMING</code>
  * has been set.
  * <br>
  * Note that whenever the length of the text affects the execution or the
  * result of a function, it is the processed length which must be considered,
  * except for <code>ubidi_setPara</code> (which receives unprocessed source
  * text) and <code>ubidi_getLength</code> (which returns the original length
  * of the source text).<br>
  * In particular, the processed length is the one to consider in the following
  * cases:
  * <ul>
  * <li>maximum value of the <code>limit</code> argument of
  * <code>ubidi_setLine</code></li>
  * <li>maximum value of the <code>charIndex</code> argument of
  * <code>ubidi_getParagraph</code></li>
  * <li>maximum value of the <code>charIndex</code> argument of
  * <code>ubidi_getLevelAt</code></li>
  * <li>number of elements in the array returned by <code>ubidi_getLevels</code></li>
  * <li>maximum value of the <code>logicalStart</code> argument of
  * <code>ubidi_getLogicalRun</code></li>
  * <li>maximum value of the <code>logicalIndex</code> argument of
  * <code>ubidi_getVisualIndex</code></li>
  * <li>number of elements filled in the <code>*indexMap</code> argument of
  * <code>ubidi_getLogicalMap</code></li>
  * <li>length of text processed by <code>ubidi_writeReordered</code></li>
  * </ul>
  *
  * @param pBiDi is the paragraph <code>UBiDi</code> object.
  *
  * @return The length of the part of the source text processed by
  *         the last call to <code>ubidi_setPara</code>.
  * @see ubidi_setPara
  * @see UBIDI_OPTION_STREAMING
  * @stable ICU 3.6
  */
 U_CAPI int32_t U_EXPORT2
 ubidi_getProcessedLength(const UBiDi *pBiDi);
 
 /**
  * Get the length of the reordered text resulting from the last call to
  * <code>ubidi_setPara()</code>. This length may be different from the length
  * of the source text if option <code>#UBIDI_OPTION_INSERT_MARKS</code>
  * or option <code>#UBIDI_OPTION_REMOVE_CONTROLS</code> has been set.
  * <br>
  * This resulting length is the one to consider in the following cases:
  * <ul>
  * <li>maximum value of the <code>visualIndex</code> argument of
  * <code>ubidi_getLogicalIndex</code></li>
  * <li>number of elements of the <code>*indexMap</code> argument of
  * <code>ubidi_getVisualMap</code></li>
  * </ul>
  * Note that this length stays identical to the source text length if
  * Bidi marks are inserted or removed using option bits of
  * <code>ubidi_writeReordered</code>, or if option
  * <code>#UBIDI_REORDER_INVERSE_NUMBERS_AS_L</code> has been set.
  *
  * @param pBiDi is the paragraph <code>UBiDi</code> object.
  *
  * @return The length of the reordered text resulting from
  *         the last call to <code>ubidi_setPara</code>.
  * @see ubidi_setPara
  * @see UBIDI_OPTION_INSERT_MARKS
  * @see UBIDI_OPTION_REMOVE_CONTROLS
  * @stable ICU 3.6
  */
 U_CAPI int32_t U_EXPORT2
 ubidi_getResultLength(const UBiDi *pBiDi);
 
 U_CDECL_BEGIN
 
 #ifndef U_HIDE_DEPRECATED_API
 /**
  * Value returned by <code>UBiDiClassCallback</code> callbacks when
  * there is no need to override the standard Bidi class for a given code point.
  *
  * This constant is deprecated; use u_getIntPropertyMaxValue(UCHAR_BIDI_CLASS)+1 instead.
  *
  * @see UBiDiClassCallback
  * @deprecated ICU 58 The numeric value may change over time, see ICU ticket #12420.
  */
 #define U_BIDI_CLASS_DEFAULT  U_CHAR_DIRECTION_COUNT
 #endif  // U_HIDE_DEPRECATED_API
 
 /**
  * Callback type declaration for overriding default Bidi class values with
  * custom ones.
  * <p>Usually, the function pointer will be propagated to a <code>UBiDi</code>
  * object by calling the <code>ubidi_setClassCallback()</code> function;
  * then the callback will be invoked by the UBA implementation any time the
  * class of a character is to be determined.</p>
  *
  * @param context is a pointer to the callback private data.
  *
  * @param c       is the code point to get a Bidi class for.
  *
  * @return The directional property / Bidi class for the given code point
  *         <code>c</code> if the default class has been overridden, or
  *         <code>u_getIntPropertyMaxValue(UCHAR_BIDI_CLASS)+1</code>
  *         if the standard Bidi class value for <code>c</code> is to be used.
  * @see ubidi_setClassCallback
  * @see ubidi_getClassCallback
  * @stable ICU 3.6
  */
 typedef UCharDirection U_CALLCONV
 UBiDiClassCallback(const void *context, UChar32 c);
 
 U_CDECL_END
 
 /**
  * Retrieve the Bidi class for a given code point.
  * <p>If a <code>#UBiDiClassCallback</code> callback is defined and returns a
  * value other than <code>u_getIntPropertyMaxValue(UCHAR_BIDI_CLASS)+1</code>,
  * that value is used; otherwise the default class determination mechanism is invoked.</p>
  *
  * @param pBiDi is the paragraph <code>UBiDi</code> object.
  *
  * @param c     is the code point whose Bidi class must be retrieved.
  *
  * @return The Bidi class for character <code>c</code> based
  *         on the given <code>pBiDi</code> instance.
  * @see UBiDiClassCallback
  * @stable ICU 3.6
  */
 U_CAPI UCharDirection U_EXPORT2
 ubidi_getCustomizedClass(UBiDi *pBiDi, UChar32 c);
 
 /**
  * Set the callback function and callback data used by the UBA
  * implementation for Bidi class determination.
  * <p>This may be useful for assigning Bidi classes to PUA characters, or
  * for special application needs. For instance, an application may want to
  * handle all spaces like L or R characters (according to the base direction)
  * when creating the visual ordering of logical lines which are part of a report
  * organized in columns: there should not be interaction between adjacent
  * cells.<p>
  *
  * @param pBiDi is the paragraph <code>UBiDi</code> object.
  *
  * @param newFn is the new callback function pointer.
  *
  * @param newContext is the new callback context pointer. This can be NULL.
  *
  * @param oldFn fillin: Returns the old callback function pointer. This can be
  *                      NULL.
  *
  * @param oldContext fillin: Returns the old callback's context. This can be
  *                           NULL.
  *
  * @param pErrorCode must be a valid pointer to an error code value.
  *
  * @see ubidi_getClassCallback
  * @stable ICU 3.6
  */
 U_CAPI void U_EXPORT2
 ubidi_setClassCallback(UBiDi *pBiDi, UBiDiClassCallback *newFn,
                        const void *newContext, UBiDiClassCallback **oldFn,
                        const void **oldContext, UErrorCode *pErrorCode);
 
 /**
  * Get the current callback function used for Bidi class determination.
  *
  * @param pBiDi is the paragraph <code>UBiDi</code> object.
  *
  * @param fn fillin: Returns the callback function pointer.
  *
  * @param context fillin: Returns the callback's private context.
  *
  * @see ubidi_setClassCallback
  * @stable ICU 3.6
  */
 U_CAPI void U_EXPORT2
 ubidi_getClassCallback(UBiDi *pBiDi, UBiDiClassCallback **fn, const void **context);
 
 /**
  * Take a <code>UBiDi</code> object containing the reordering
  * information for a piece of text (one or more paragraphs) set by
  * <code>ubidi_setPara()</code> or for a line of text set by
  * <code>ubidi_setLine()</code> and write a reordered string to the
  * destination buffer.
  *
  * This function preserves the integrity of characters with multiple
  * code units and (optionally) combining characters.
  * Characters in RTL runs can be replaced by mirror-image characters
  * in the destination buffer. Note that "real" mirroring has
  * to be done in a rendering engine by glyph selection
  * and that for many "mirrored" characters there are no
  * Unicode characters as mirror-image equivalents.
  * There are also options to insert or remove Bidi control
  * characters; see the description of the <code>destSize</code>
  * and <code>options</code> parameters and of the option bit flags.
  *
  * @param pBiDi A pointer to a <code>UBiDi</code> object that
  *              is set by <code>ubidi_setPara()</code> or
  *              <code>ubidi_setLine()</code> and contains the reordering
  *              information for the text that it was defined for,
  *              as well as a pointer to that text.<br><br>
  *              The text was aliased (only the pointer was stored
  *              without copying the contents) and must not have been modified
  *              since the <code>ubidi_setPara()</code> call.
  *
  * @param dest A pointer to where the reordered text is to be copied.
  *             The source text and <code>dest[destSize]</code>
  *             must not overlap.
  *
  * @param destSize The size of the <code>dest</code> buffer,
  *                 in number of UChars.
  *                 If the <code>UBIDI_INSERT_LRM_FOR_NUMERIC</code>
  *                 option is set, then the destination length could be
  *                 as large as
  *                 <code>ubidi_getLength(pBiDi)+2*ubidi_countRuns(pBiDi)</code>.
  *                 If the <code>UBIDI_REMOVE_BIDI_CONTROLS</code> option
  *                 is set, then the destination length may be less than
  *                 <code>ubidi_getLength(pBiDi)</code>.
  *                 If none of these options is set, then the destination length
  *                 will be exactly <code>ubidi_getProcessedLength(pBiDi)</code>.
  *
  * @param options A bit set of options for the reordering that control
  *                how the reordered text is written.
  *                The options include mirroring the characters on a code
  *                point basis and inserting LRM characters, which is used
  *                especially for transforming visually stored text
  *                to logically stored text (although this is still an
  *                imperfect implementation of an "inverse Bidi" algorithm
  *                because it uses the "forward Bidi" algorithm at its core).
  *                The available options are:
  *                <code>#UBIDI_DO_MIRRORING</code>,
  *                <code>#UBIDI_INSERT_LRM_FOR_NUMERIC</code>,
  *                <code>#UBIDI_KEEP_BASE_COMBINING</code>,
  *                <code>#UBIDI_OUTPUT_REVERSE</code>,
  *                <code>#UBIDI_REMOVE_BIDI_CONTROLS</code>
  *
  * @param pErrorCode must be a valid pointer to an error code value.
  *
  * @return The length of the output string.
  *
  * @see ubidi_getProcessedLength
  * @stable ICU 2.0
  */
 U_CAPI int32_t U_EXPORT2
 ubidi_writeReordered(UBiDi *pBiDi,
                      UChar *dest, int32_t destSize,
                      uint16_t options,
                      UErrorCode *pErrorCode);
 
 /**
  * Reverse a Right-To-Left run of Unicode text.
  *
  * This function preserves the integrity of characters with multiple
  * code units and (optionally) combining characters.
  * Characters can be replaced by mirror-image characters
  * in the destination buffer. Note that "real" mirroring has
  * to be done in a rendering engine by glyph selection
  * and that for many "mirrored" characters there are no
  * Unicode characters as mirror-image equivalents.
  * There are also options to insert or remove Bidi control
  * characters.
  *
  * This function is the implementation for reversing RTL runs as part
  * of <code>ubidi_writeReordered()</code>. For detailed descriptions
  * of the parameters, see there.
  * Since no Bidi controls are inserted here, the output string length
  * will never exceed <code>srcLength</code>.
  *
  * @see ubidi_writeReordered
  *
  * @param src A pointer to the RTL run text.
  *
  * @param srcLength The length of the RTL run.
  *
  * @param dest A pointer to where the reordered text is to be copied.
  *             <code>src[srcLength]</code> and <code>dest[destSize]</code>
  *             must not overlap.
  *
  * @param destSize The size of the <code>dest</code> buffer,
  *                 in number of UChars.
  *                 If the <code>UBIDI_REMOVE_BIDI_CONTROLS</code> option
  *                 is set, then the destination length may be less than
  *                 <code>srcLength</code>.
  *                 If this option is not set, then the destination length
  *                 will be exactly <code>srcLength</code>.
  *
  * @param options A bit set of options for the reordering that control
  *                how the reordered text is written.
  *                See the <code>options</code> parameter in <code>ubidi_writeReordered()</code>.
  *
  * @param pErrorCode must be a valid pointer to an error code value.
  *
  * @return The length of the output string.
  * @stable ICU 2.0
  */
 U_CAPI int32_t U_EXPORT2
 ubidi_writeReverse(const UChar *src, int32_t srcLength,
                    UChar *dest, int32_t destSize,
                    uint16_t options,
                    UErrorCode *pErrorCode);
 
 /*#define BIDI_SAMPLE_CODE*/
 /*@}*/
 
 #endif

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