/* ****************************************************************************** * * Copyright (C) 1999-2004, 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 */ #ifndef UBIDI_H #define UBIDI_H #include "unicode/utypes.h" #include "unicode/uchar.h" /* * javadoc-style comments are intended to be transformed into HTML * using DOC++ - see * http://www.zib.de/Visual/software/doc++/index.html . * * The HTML documentation is created with * doc++ -H ubidi.h * * The following #define trick allows us to do it all in one file * and still be able to compile it. */ /*#define DOCXX_TAG*/ /*#define BIDI_SAMPLE_CODE*/ /** *\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>, * version 13, also described in The Unicode Standard, Version 4.0 .<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 "limit" 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 "runs". * Such a "run" 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 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 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. * 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 <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 /** * <code>UBiDiDirection</code> 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 <code>UBiDi</code> structure for the declaration of * the API functions. Its fields are implementation-specific.<p> * This structure holds information about a paragraph 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 a paragraph which is * then interpreted 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 paragraph by <code>ubidi_setPara()</code> * or the BiDi properties of a line of 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_set()</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 paragraph 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.<p> * The number of runs depends on the actual text and maybe anywhere between * 1 and <code>maxLength</code>. It is typically small.<p> * * @param pErrorCode must be a valid pointer to an error code value, * which must not indicate a failure before the function call. * * @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 is the <i>child</i> * of another one (its <i>parent</i>), after 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); /** * 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> * * @param pBiDi is a <code>UBiDi</code> 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 <code>UBiDi</code> object. * @return TRUE if the BiDi object set to perform the inverse BiDi algorithm * * @see ubidi_setInverse * @stable ICU 2.0 */ U_STABLE UBool U_EXPORT2 ubidi_isInverse(UBiDi *pBiDi); /** * 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 single plain text paragraph 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 paragraph consists of text of only one direction, 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 must be externally split into separate paragraphs (rule P1). * Paragraph separators (B) should appear at most at the very end. * * @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 single-paragraph text that the * BiDi algorithm will be performed on * (step (P1) of the algorithm is performed externally). * <strong>The text must be (at least) <code>length</code> long.</strong> * This pointer is stored in the UBiDi object and can be retrieved * with <code>ubidi_getText()</code>. * * @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 paragraph; * 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 there is no 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.<p> * Except for that bit, it must be * <code>paraLevel<=embeddingLevels[]<=UBIDI_MAX_EXPLICIT_LEVEL</code>.<p> * <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.<p> * After the <code>UBiDi</code> object is reused or destroyed, the caller * must take care of the deallocation of the <code>embeddingLevels</code> array.<p> * <strong>The <code>embeddingLevels</code> array must be * at least <code>length</code> long.</strong> * * @param pErrorCode must be a valid pointer to an error code value, * which must not indicate a failure before the function call. * @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 paragraph of text, and by specifying * a range of indexes in this paragraph.<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 paragraph, and after line-breaking on that paragraph. * It is not necessary if the 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. * * @param start is the line's first index into the paragraph text. * * @param limit is just behind the line's last index into the paragraph text * (its last index +1).<br> * It must be <code>0<=start<=limit<=</code>paragraph length. * * @param pLineBiDi is the object that will now represent a line of the paragraph. * * @param pErrorCode must be a valid pointer to an error code value, * which must not indicate a failure before the function call. * * @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 <code>UBiDi</code> object. * * @return A <code>UBIDI_XXX</code> 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 <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. * * @see UBiDiLevel * @stable ICU 2.0 */ U_STABLE UBiDiLevel U_EXPORT2 ubidi_getParaLevel(const UBiDi *pBiDi); /** * Get the level for one character. * * @param pBiDi is the paragraph or line <code>UBiDi</code> 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.<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. * * @param pErrorCode must be a valid pointer to an error code value, * which must not indicate a failure before the function call. * * @return The levels array for the text, * or <code>NULL</code> 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.<p> * This is especially useful for line-breaking on a paragraph. * * @param pBiDi is the paragraph or line <code>UBiDi</code> 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 * <code>logicalStart</code>. * This pointer can be <code>NULL</code> if this * value is not necessary. * * @param pLevel will receive the level of the run. * This pointer can be <code>NULL</code> 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 * <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, * which must not indicate a failure before the function call. * * @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>. * * @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 * modifier letters before base characters and second surrogates * before first ones. * @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> * * Note that in right-to-left runs, this mapping places * modifier letters before base characters and second surrogates * before first ones. * * @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, * which must not indicate a failure before the function call. * * @return The visual position of this character. * * @see ubidi_getLogicalMap * @see ubidi_getLogicalIndex * @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> * * This is the inverse function to <code>ubidi_getVisualIndex()</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, * which must not indicate a failure before the function call. * * @return The index of this character in the text. * * @see ubidi_getVisualMap * @see ubidi_getVisualIndex * @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. * * @param pBiDi is the paragraph or line <code>UBiDi</code> object. * * @param indexMap is a pointer to an array of <code>ubidi_getLength()</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>.<p> * * @param pErrorCode must be a valid pointer to an error code value, * which must not indicate a failure before the function call. * * @see ubidi_getVisualMap * @see ubidi_getVisualIndex * @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. * * @param pBiDi is the paragraph or line <code>UBiDi</code> object. * * @param indexMap is a pointer to an array of <code>ubidi_getLength()</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>.<p> * * @param pErrorCode must be a valid pointer to an error code value, * which must not indicate a failure before the function call. * * @see ubidi_getLogicalMap * @see ubidi_getLogicalIndex * @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 one-to-one index mapping of the first map is inverted and written to * the second one. * * @param srcMap is an array with <code>length</code> indexes * which define the original mapping. * * @param destMap is an array with <code>length</code> indexes * which will be filled with the inverse mapping. * * @param length is the length of each array. * @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 * * @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) * * @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 /** * Take a <code>UBiDi</code> object containing the reordering * information for one paragraph or line of text as set by * <code>ubidi_setPara()</code> or <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) modifier letters. * 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. * * @see UBIDI_DO_MIRRORING * @see UBIDI_INSERT_LRM_FOR_NUMERIC * @see UBIDI_KEEP_BASE_COMBINING * @see UBIDI_OUTPUT_REVERSE * @see UBIDI_REMOVE_BIDI_CONTROLS * * @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. * <p>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.</p> * * @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_getLength(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, * which must not indicate a failure before the function call. * * @return The length of the output string. * @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) modifier letters. * 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, * which must not indicate a failure before the function call. * * @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