+ * + * 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". + * + *
pErrorCode 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.+ * + * The "limit" of a sequence of characters is the position just after their + * last character, i.e., one more than that position.
+ * + * Some of the API functions provide access to "runs". + * Such a "run" is defined as a sequence of characters + * that are at the same embedding level + * after performing the BIDI algorithm.
+ * + * @author Markus W. Scherer + * @version 1.0 + * + * + *
The basic assumptions are:
+ *
+ * \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; ilimit) { 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=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
+ *
+ */
+
+/*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 0 (even/odd value).
+ *
+ * It can also hold non-level values for the
+ * paraLevel and embeddingLevels
+ * arguments of ubidi_setPara(); there:
+ *
embeddingLevels[]
+ * value indicates whether the using application is
+ * specifying the level of a character to override whatever the
+ * BiDi implementation would resolve it to.paraLevel can be set to the
+ * pseudo-level values UBIDI_DEFAULT_LTR
+ * and UBIDI_DEFAULT_RTL.The related constants are not real, valid level values.
+ * UBIDI_DEFAULT_XXX can be used to specify
+ * a default for the paragraph level for
+ * when the ubidi_setPara() function
+ * shall determine it but there is no
+ * strongly typed character in the input.
+ *
+ * Note that the value for UBIDI_DEFAULT_LTR is even
+ * and the one for UBIDI_DEFAULT_RTL 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.
+ * If there is no strong character, then set the paragraph level to 0 (left-to-right).
+ * @stable ICU 2.0
+ */
+#define UBIDI_DEFAULT_LTR 0xfe
+
+/** Paragraph level setting.
+ * If there is no strong character, then set the paragraph level to 1 (right-to-left).
+ * @stable ICU 2.0
+ */
+#define UBIDI_DEFAULT_RTL 0xff
+
+/**
+ * Maximum explicit embedding level.
+ * (The maximum resolved level can be up to UBIDI_MAX_EXPLICIT_LEVEL+1).
+ * @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
+
+/**
+ * UBiDiDirection values indicate the text direction.
+ * @stable ICU 2.0
+ */
+enum UBiDiDirection {
+ /** All left-to-right text. This is a 0 value. @stable ICU 2.0 */
+ UBIDI_LTR,
+ /** All right-to-left text. This is a 1 value. @stable ICU 2.0 */
+ UBIDI_RTL,
+ /** Mixed-directional text. @stable ICU 2.0 */
+ UBIDI_MIXED
+};
+
+/** @stable ICU 2.0 */
+typedef enum UBiDiDirection UBiDiDirection;
+
+/**
+ * Forward declaration of the UBiDi structure for the declaration of
+ * the API functions. Its fields are implementation-specific.
+ * 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.
+ * 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 UBiDi structure.
+ * Such an object is initially empty. It is assigned
+ * the BiDi properties of a piece of text containing one or more paragraphs
+ * by ubidi_setPara()
+ * or the BiDi properties of a line within a paragraph by
+ * ubidi_setLine().
+ * This object can be reused for as long as it is not deallocated
+ * by calling ubidi_close().
+ * ubidi_setPara() and ubidi_setLine() will allocate
+ * additional memory for internal structures as necessary.
+ *
+ * @return An empty UBiDi object.
+ * @stable ICU 2.0
+ */
+U_STABLE UBiDi * U_EXPORT2
+ubidi_open(void);
+
+/**
+ * Allocate a UBiDi structure with preallocated memory
+ * for internal structures.
+ * This function provides a UBiDi object like ubidi_open()
+ * with no arguments, but it also preallocates memory for internal structures
+ * according to the sizings supplied by the caller.
+ * Subsequent functions will not allocate any more memory, and are thus + * guaranteed not to fail because of lack of memory.
+ * The preallocation can be limited to some of the internal memory
+ * by setting some values to 0 here. That means that if, e.g.,
+ * maxRunCount cannot be reasonably predetermined and should not
+ * be set to maxLength (the only failproof value) to avoid
+ * wasting memory, then maxRunCount could be set to 0 here
+ * and the internal structures that are associated with it will be allocated
+ * on demand, just like with ubidi_open().
+ *
+ * @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.
+ * The number of runs depends on the actual text and maybe anywhere between
+ * 1 and maxLength. It is typically small.
+ *
+ * @param pErrorCode must be a valid pointer to an error code value.
+ *
+ * @return An empty UBiDi object with preallocated memory.
+ * @stable ICU 2.0
+ */
+U_STABLE UBiDi * U_EXPORT2
+ubidi_openSized(int32_t maxLength, int32_t maxRunCount, UErrorCode *pErrorCode);
+
+/**
+ * ubidi_close() must be called to free the memory
+ * associated with a UBiDi object.
+ *
+ * Important:
+ * A parent UBiDi object must not be destroyed or reused if
+ * it still has children.
+ * If a UBiDi object is the child
+ * of another one (its parent), after calling
+ * ubidi_setLine(), then the child object must
+ * be destroyed (closed) or reused (by calling
+ * ubidi_setPara() or ubidi_setLine())
+ * before the parent object.
+ *
+ * @param pBiDi is a UBiDi object.
+ *
+ * @see ubidi_setPara
+ * @see ubidi_setLine
+ * @stable ICU 2.0
+ */
+U_STABLE void U_EXPORT2
+ubidi_close(UBiDi *pBiDi);
+
+/**
+ * Modify the operation of the BiDi algorithm such that it
+ * approximates an "inverse BiDi" algorithm. This function
+ * must be called before ubidi_setPara().
+ *
+ *
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".
+ * + *With isInverse set to TRUE,
+ * 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.
Output runs should be retrieved using ubidi_getVisualRun().
+ * Since the actual input for "inverse BiDi" is visually ordered text and
+ * ubidi_getVisualRun() gets the reordered runs, these are actually
+ * the runs of the logically ordered output.
UBiDi object.
+ *
+ * @param isInverse specifies "forward" or "inverse" BiDi operation
+ *
+ * @see ubidi_setPara
+ * @see ubidi_writeReordered
+ * @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?
+ *
+ * @param pBiDi is a UBiDi object.
+ * @return TRUE if the BiDi object is set to perform the inverse BiDi algorithm
+ *
+ * @see ubidi_setInverse
+ * @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 ubidi_setPara().
+ * 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 UBiDi 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 UBiDi 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);
+
+/**
+ * Perform the Unicode BiDi algorithm. It is defined in the
+ * Unicode Standard Anned #9,
+ * version 13,
+ * also described in The Unicode Standard, Version 4.0 .+ * + * This function takes a piece of plain text containing one or more paragraphs, + * with or without externally specified embedding levels from styled + * text and computes the left-right-directionality of each character.
+ *
+ * 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.
+ * 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.
+ *
+ * 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 UBiDi object allocated with ubidi_open()
+ * which will be set to contain the reordering information,
+ * especially the resolved levels for all the characters in text.
+ *
+ * @param text is a pointer to the text that the
+ * BiDi algorithm will be performed on
+ * The text must be (at least) length long.
+ * This pointer is stored in the UBiDi object and can be retrieved
+ * with ubidi_getText().
+ *
+ * @param length is the length of the text; if length==-1 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 paraLevel can be set to
+ * either UBIDI_DEFAULT_LTR
+ * or UBIDI_DEFAULT_RTL; 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 UBIDI_MAX_EXPLICIT_LEVEL 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
+ * UBIDI_LEVEL_OVERRIDE bit set.
+ * Except for that bit, it must be
+ * paraLevel<=embeddingLevels[]<=UBIDI_MAX_EXPLICIT_LEVEL,
+ * with one exception: a level of zero may be specified for a paragraph
+ * separator even if paraLevel>0 when multiple paragraphs
+ * are submitted in the same call to ubidi_setPara().
+ * Caution: A copy of this pointer, not of the levels,
+ * will be stored in the UBiDi object;
+ * the embeddingLevels array must not be
+ * deallocated before the UBiDi structure is destroyed or reused,
+ * and the embeddingLevels
+ * should not be modified to avoid unexpected results on subsequent BiDi operations.
+ * However, the ubidi_setPara() and
+ * ubidi_setLine() functions may modify some or all of the levels.
+ * After the UBiDi object is reused or destroyed, the caller
+ * must take care of the deallocation of the embeddingLevels array.
+ * The embeddingLevels array must be
+ * at least length long.
+ *
+ * @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);
+
+/**
+ * ubidi_setLine() sets a UBiDi 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 UBiDi object representing
+ * this information for a piece of text containing one or more paragraphs,
+ * and by specifying a range of indexes in this text.
+ * In the new line object, the indexes will range from 0 to limit-start-1.
+ *
+ * This is used after calling ubidi_setPara()
+ * 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.
+ *
+ * After line-breaking, rules (L1) and (L2) for the treatment of
+ * trailing WS and for reordering are performed on
+ * a UBiDi object that represents a line.
+ *
+ * Important: pLineBiDi shares data with
+ * pParaBiDi.
+ * You must destroy or reuse pLineBiDi before pParaBiDi.
+ * In other words, you must destroy or reuse the UBiDi object for a line
+ * before the object for its parent paragraph.
+ *
+ * The text pointer that was stored in pParaBiDi is also copied,
+ * and start 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).
+ * It must be 0<=start<=limit<=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
+ * @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 UBiDi object.
+ *
+ * @return A UBIDI_XXX value that indicates if the entire text
+ * represented by this object is unidirectional,
+ * and which direction, or if it is mixed-directional.
+ *
+ * @see UBiDiDirection
+ * @stable ICU 2.0
+ */
+U_STABLE UBiDiDirection U_EXPORT2
+ubidi_getDirection(const UBiDi *pBiDi);
+
+/**
+ * Get the pointer to the text.
+ *
+ * @param pBiDi is the paragraph or line UBiDi 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 UBiDi 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 UBiDi 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 UBiDi 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.
+ *
+ * @param pBiDi is the paragraph or line UBiDi object.
+ *
+ * @param charIndex is the index of a character within the text, in the
+ * range [0..ubidi_getLength(pBiDi)-1].
+ *
+ * @param pParaStart will receive the index of the first character of the
+ * paragraph in the text.
+ * This pointer can be NULL 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
+ * charIndex.
+ * This pointer can be NULL if this
+ * value is not necessary.
+ *
+ * @param pParaLevel will receive the level of the paragraph.
+ * This pointer can be NULL 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.
+ * @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.
+ *
+ * @param pBiDi is the paragraph UBiDi object.
+ *
+ * @param paraIndex is the number of the paragraph, in the
+ * range [0..ubidi_countParagraphs(pBiDi)-1].
+ *
+ * @param pParaStart will receive the index of the first character of the
+ * paragraph in the text.
+ * This pointer can be NULL if this
+ * value is not necessary.
+ *
+ * @param pParaLimit will receive the limit of the paragraph.
+ * This pointer can be NULL if this
+ * value is not necessary.
+ *
+ * @param pParaLevel will receive the level of the paragraph.
+ * This pointer can be NULL 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 UBiDi object.
+ *
+ * @param charIndex the index of a character.
+ *
+ * @return The level for the character at charIndex.
+ *
+ * @see UBiDiLevel
+ * @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.
+ *
+ * Note that this function may allocate memory under some
+ * circumstances, unlike ubidi_getLevelAt().
+ *
+ * @param pBiDi is the paragraph or line UBiDi 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 NULL if an error occurs.
+ *
+ * @see UBiDiLevel
+ * @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.
+ * This is especially useful for line-breaking on a paragraph.
+ *
+ * @param pBiDi is the paragraph or line UBiDi object.
+ *
+ * @param logicalStart is the first character of the run.
+ *
+ * @param pLogicalLimit will receive the limit of the run.
+ * The l-value that you point to here may be the
+ * same expression (variable) as the one for
+ * logicalStart.
+ * This pointer can be NULL if this
+ * value is not necessary.
+ *
+ * @param pLevel will receive the level of the run.
+ * This pointer can be NULL if this
+ * value is not necessary.
+ * @stable ICU 2.0
+ */
+U_STABLE void U_EXPORT2
+ubidi_getLogicalRun(const UBiDi *pBiDi, int32_t logicalStart,
+ int32_t *pLogicalLimit, UBiDiLevel *pLevel);
+
+/**
+ * Get the number of runs.
+ * This function may invoke the actual reordering on the
+ * UBiDi object, after ubidi_setPara()
+ * may have resolved only the levels of the text. Therefore,
+ * ubidi_countRuns() may have to allocate memory,
+ * and may fail doing so.
+ *
+ * @param pBiDi is the paragraph or line UBiDi 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.
+ * ubidi_countRuns() should be called
+ * before the runs are retrieved.
+ *
+ * @param pBiDi is the paragraph or line UBiDi object.
+ *
+ * @param runIndex is the number of the run in visual order, in the
+ * range [0..ubidi_countRuns(pBiDi)-1].
+ *
+ * @param pLogicalStart is the first logical character index in the text.
+ * The pointer may be NULL if this index is not needed.
+ *
+ * @param pLength is the number of characters (at least one) in the run.
+ * The pointer may be NULL if this is not needed.
+ *
+ * @return the directionality of the run,
+ * UBIDI_LTR==0 or UBIDI_RTL==1,
+ * never UBIDI_MIXED.
+ *
+ * @see ubidi_countRuns
+ *
+ * Example:
+ *