Check in the pristine copy of ICU 51.2

icu51/source/common/unicode/ubidi.h

Index: icu51/source/common/unicode/ubidi.h
===================================================================
--- icu51/source/common/unicode/ubidi.h	(revision 0)
+++ icu51/source/common/unicode/ubidi.h	(revision 0)
@@ -0,0 +1,2186 @@
+/*
+******************************************************************************
+*
+*   Copyright (C) 1999-2012, International Business Machines
+*   Corporation and others.  All Rights Reserved.
+*
+******************************************************************************
+*   file name:  ubidi.h
+*   encoding:   US-ASCII
+*   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"
+#include "unicode/localpointer.h"
+
+/**
+ *\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=styleRun[i].limit;
+ *             if(start<styleLimit) {
+ *                 if(styleLimit>limit) { styleLimit=limit; }
+ *                 renderRun(text, start, styleLimit,
+ *                           direction, styleRun[i].style);
+ *                 if(styleLimit==limit) { break; }
+ *                 start=styleLimit;
+ *             }
+ *         }
+ *     } else {
+ *         int styleStart;
+ *
+ *         for(i=styleRunCount-1; i>=0; --i) {
+ *             if(i>0) {
+ *                 styleStart=styleRun[i-1].limit;
+ *             } else {
+ *                 styleStart=0;
+ *             }
+ *             if(limit>=styleStart) {
+ *                 if(styleStart<start) { styleStart=start; }
+ *                 renderRun(text, styleStart, limit,
+ *                           direction, styleRun[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) {
+ *     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(para, 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(para, 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);
+ *         } 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);
+ *                     }
+ *                     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.
+ *
+ * @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.
+ * (The maximum resolved level can be up to <code>UBIDI_MAX_EXPLICIT_LEVEL+1</code>).
+ * @stable ICU 2.0
+ */
+#define UBIDI_MAX_EXPLICIT_LEVEL 61
+
+/** 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_STABLE 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_STABLE 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_STABLE 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_STABLE 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_STABLE 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_STABLE 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_STABLE 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
+      * mimicks 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,
+    /** Number of values for reordering mode.
+      * @stable ICU 3.6 */
+    UBIDI_REORDER_COUNT
+} 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_STABLE 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_STABLE 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_STABLE 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_STABLE 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_STABLE 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 Anned #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>
+ *        Except for that bit, it must be
+ *        <code>paraLevel<=embeddingLevels[]<=UBIDI_MAX_EXPLICIT_LEVEL</code>,
+ *        with one exception: a level of zero may be specified for a paragraph
+ *        separator even if <code>paraLevel>0</code> when multiple paragraphs
+ *        are submitted in the same call to <code>ubidi_setPara()</code>.<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_STABLE void U_EXPORT2
+ubidi_setPara(UBiDi *pBiDi, const UChar *text, int32_t length,
+              UBiDiLevel paraLevel, UBiDiLevel *embeddingLevels,
+              UErrorCode *pErrorCode);
+
+/**
+ * <code>ubidi_setLine()</code> sets a <code>UBiDi</code> to
+ * contain the reordering information, especially the resolved levels,
+ * for all the characters in a line of text. This line of text is
+ * specified by referring to a <code>UBiDi</code> object representing
+ * this information for a 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_STABLE void U_EXPORT2
+ubidi_setLine(const UBiDi *pParaBiDi,
+              int32_t start, int32_t limit,
+              UBiDi *pLineBiDi,
+              UErrorCode *pErrorCode);
+
+/**
+ * Get the directionality of the text.
+ *
+ * @param pBiDi is the paragraph or line <code>UBiDi</code> object.
+ *
+ * @return a 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_STABLE 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_STABLE 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_STABLE const UChar * U_EXPORT2
+ubidi_getText(const UBiDi *pBiDi);
+
+/**
+ * Get the length of the text.
+ *
+ * @param pBiDi is the paragraph or line <code>UBiDi</code> object.
+ *
+ * @return The length of the text that the UBiDi object was created for.
+ * @stable ICU 2.0
+ */
+U_STABLE int32_t U_EXPORT2
+ubidi_getLength(const UBiDi *pBiDi);
+
+/**
+ * Get the paragraph level of the text.
+ *
+ * @param pBiDi is the paragraph or line <code>UBiDi</code> object.
+ *
+ * @return The paragraph level. 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_STABLE 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_STABLE 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_STABLE 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_STABLE 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_STABLE UBiDiLevel U_EXPORT2
+ubidi_getLevelAt(const UBiDi *pBiDi, int32_t charIndex);
+
+/**
+ * Get an array of levels for each character.<p>
+ *
+ * Note that this function may allocate memory under some
+ * circumstances, unlike <code>ubidi_getLevelAt()</code>.
+ *
+ * @param pBiDi is the paragraph or line <code>UBiDi</code> object, 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_STABLE const UBiDiLevel * U_EXPORT2
+ubidi_getLevels(UBiDi *pBiDi, UErrorCode *pErrorCode);
+
+/**
+ * Get a logical run.
+ * This function returns information about a run and is used
+ * to retrieve runs in logical order.<p>
+ * This is especially useful for line-breaking on a paragraph.
+ *
+ * @param pBiDi is the paragraph or line <code>UBiDi</code> object.
+ *
+ * @param 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_STABLE 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_STABLE int32_t U_EXPORT2
+ubidi_countRuns(UBiDi *pBiDi, UErrorCode *pErrorCode);
+
+/**
+ * Get one run's logical start, length, and directionality,
+ * which can be 0 for LTR or 1 for RTL.
+ * In an RTL run, the character at the logical start is
+ * visually on the right of the displayed run.
+ * The length is the number of characters in the run.<p>
+ * <code>ubidi_countRuns()</code> should be called
+ * before the runs are retrieved.
+ *
+ * @param pBiDi is the paragraph or line <code>UBiDi</code> object.
+ *
+ * @param runIndex is the number of the run in visual order, in the
+ *        range <code>[0..ubidi_countRuns(pBiDi)-1]</code>.
+ *
+ * @param pLogicalStart is the first logical character index in the text.
+ *        The pointer may be <code>NULL</code> if this index is not needed.
+ *
+ * @param pLength is the number of characters (at least one) in the run.
+ *        The pointer may be <code>NULL</code> if this is not needed.
+ *
+ * @return the directionality of the run,
+ *         <code>UBIDI_LTR==0</code> or <code>UBIDI_RTL==1</code>,
+ *         never <code>UBIDI_MIXED</code>,
+ *         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_STABLE UBiDiDirection U_EXPORT2
+ubidi_getVisualRun(UBiDi *pBiDi, int32_t runIndex,
+                   int32_t *pLogicalStart, int32_t *pLength);
+
+/**
+ * Get the visual position from a logical text position.
+ * If such a mapping is used many times on the same
+ * <code>UBiDi</code> object, then calling
+ * <code>ubidi_getLogicalMap()</code> is more efficient.<p>
+ *
+ * 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_STABLE int32_t U_EXPORT2
+ubidi_getVisualIndex(UBiDi *pBiDi, int32_t logicalIndex, UErrorCode *pErrorCode);
+
+/**
+ * Get the logical text position from a visual position.
+ * If such a mapping is used many times on the same
+ * <code>UBiDi</code> object, then calling
+ * <code>ubidi_getVisualMap()</code> is more efficient.<p>
+ *
+ * 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_STABLE int32_t U_EXPORT2
+ubidi_getLogicalIndex(UBiDi *pBiDi, int32_t visualIndex, UErrorCode *pErrorCode);
+
+/**
+ * Get a logical-to-visual index map (array) for the characters in the UBiDi
+ * (paragraph or line) object.
+ * <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_STABLE void U_EXPORT2
+ubidi_getLogicalMap(UBiDi *pBiDi, int32_t *indexMap, UErrorCode *pErrorCode);
+
+/**
+ * Get a visual-to-logical index map (array) for the characters in the UBiDi
+ * (paragraph or line) object.
+ * <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_STABLE void U_EXPORT2
+ubidi_getVisualMap(UBiDi *pBiDi, int32_t *indexMap, UErrorCode *pErrorCode);
+
+/**
+ * This is a convenience function that does not use a UBiDi object.
+ * It is intended to be used for when an application has determined the levels
+ * of objects (character sequences) and just needs to have them reordered (L2).
+ * This is equivalent to using <code>ubidi_getLogicalMap()</code> on a
+ * <code>UBiDi</code> object.
+ *
+ * @param levels is an array with <code>length</code> levels that have been determined by
+ *        the application.
+ *
+ * @param length is the number of levels in the array, or, semantically,
+ *        the number of objects to be reordered.
+ *        It must be <code>length>0</code>.
+ *
+ * @param indexMap is a pointer to an array of <code>length</code>
+ *        indexes which will reflect the reordering of the characters.
+ *        The array does not need to be initialized.<p>
+ *        The index map will result in <code>indexMap[logicalIndex]==visualIndex</code>.
+ * @stable ICU 2.0
+ */
+U_STABLE void U_EXPORT2
+ubidi_reorderLogical(const UBiDiLevel *levels, int32_t length, int32_t *indexMap);
+
+/**
+ * This is a convenience function that does not use a UBiDi object.
+ * It is intended to be used for when an application has determined the levels
+ * of objects (character sequences) and just needs to have them reordered (L2).
+ * This is equivalent to using <code>ubidi_getVisualMap()</code> on a
+ * <code>UBiDi</code> object.
+ *
+ * @param levels is an array with <code>length</code> levels that have been determined by
+ *        the application.
+ *
+ * @param length is the number of levels in the array, or, semantically,
+ *        the number of objects to be reordered.
+ *        It must be <code>length>0</code>.
+ *
+ * @param indexMap is a pointer to an array of <code>length</code>
+ *        indexes which will reflect the reordering of the characters.
+ *        The array does not need to be initialized.<p>
+ *        The index map will result in <code>indexMap[visualIndex]==logicalIndex</code>.
+ * @stable ICU 2.0
+ */
+U_STABLE void U_EXPORT2
+ubidi_reorderVisual(const UBiDiLevel *levels, int32_t length, int32_t *indexMap);
+
+/**
+ * Invert an index map.
+ * The 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_STABLE void U_EXPORT2
+ubidi_invertMap(const int32_t *srcMap, int32_t *destMap, int32_t length);
+
+/** option flags for ubidi_writeReordered() */
+
+/**
+ * option bit for ubidi_writeReordered():
+ * keep combining characters after their base characters in RTL runs
+ *
+ * @see ubidi_writeReordered
+ * @stable ICU 2.0
+ */
+#define UBIDI_KEEP_BASE_COMBINING       1
+
+/**
+ * option bit for ubidi_writeReordered():
+ * replace characters with the "mirrored" property in RTL runs
+ * by their mirror-image mappings
+ *
+ * @see ubidi_writeReordered
+ * @stable ICU 2.0
+ */
+#define UBIDI_DO_MIRRORING              2
+
+/**
+ * option bit for ubidi_writeReordered():
+ * surround the run with LRMs if necessary;
+ * this is part of the approximate "inverse Bidi" algorithm
+ *
+ * <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_STABLE 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_STABLE int32_t U_EXPORT2
+ubidi_getResultLength(const UBiDi *pBiDi);
+
+U_CDECL_BEGIN
+/**
+ * value returned by <code>UBiDiClassCallback</code> callbacks when
+ * there is no need to override the standard Bidi class for a given code point.
+ * @see UBiDiClassCallback
+ * @stable ICU 3.6
+ */
+#define U_BIDI_CLASS_DEFAULT  U_CHAR_DIRECTION_COUNT
+
+/**
+ * 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_BIDI_CLASS_DEFAULT</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_BIDI_CLASS_DEFAULT</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_STABLE 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_STABLE 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_STABLE 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_STABLE int32_t U_EXPORT2
+ubidi_writeReordered(UBiDi *pBiDi,
+                     UChar *dest, int32_t destSize,
+                     uint16_t options,
+                     UErrorCode *pErrorCode);
+
+/**
+ * Reverse a Right-To-Left run of Unicode text.
+ *
+ * This function preserves the integrity of characters with multiple
+ * code units and (optionally) 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_STABLE int32_t U_EXPORT2
+ubidi_writeReverse(const UChar *src, int32_t srcLength,
+                   UChar *dest, int32_t destSize,
+                   uint16_t options,
+                   UErrorCode *pErrorCode);
+
+/*#define BIDI_SAMPLE_CODE*/
+/*@}*/
+
+#endif
Property changes on: icu51/source/common/unicode/ubidi.h
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Added: svn:eol-style
   + LF