| /* |
| ******************************************************************************* |
| * * |
| * COPYRIGHT: * |
| * (C) Copyright International Business Machines Corporation, 1999 * |
| * Licensed Material - Program-Property of IBM - All Rights Reserved. * |
| * US Government Users Restricted Rights - Use, duplication, or disclosure * |
| * restricted by GSA ADP Schedule Contract with IBM Corp. * |
| * * |
| ******************************************************************************* |
| * 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 "utypes.h" |
| #include "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 |
| |
| /** |
| * @name BiDi algorithm for ICU |
| * |
| * <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 Technical Report 9</a>, |
| * version 5, also described in The Unicode Standard, Version 3.0 .<p> |
| * |
| * <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 <quote>limit</quote> 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 <quote>runs</quote>. |
| * Such a <quote>run</quote> 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 |
| */ |
| 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 |
| * pesudo-level values <code>UBIDI_DEFAULT_LTR</code> |
| * and <code>UBIDI_DEFAULT_RTL</code>.</li> |
| * |
| * @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 |
| */ |
| typedef uint8_t UBiDiLevel; |
| |
| /** @memo If there is no strong character, then set the paragraph level to 0 (left-to-right). */ |
| #define UBIDI_DEFAULT_LTR 0xfe |
| |
| /** @memo If there is no strong character, then set the paragraph level to 1 (right-to-left). */ |
| #define UBIDI_DEFAULT_RTL 0xff |
| |
| /** |
| * @memo Maximum explicit embedding level |
| * (The maximum resolved level can be up to <code>UBIDI_MAX_EXPLICIT_LEVEL+1</code>). |
| */ |
| #define UBIDI_MAX_EXPLICIT_LEVEL 61 |
| |
| /** @memo Bit flag for level input: overrides directional properties. */ |
| #define UBIDI_LEVEL_OVERRIDE 0x80 |
| |
| /** |
| * @memo <code>UBiDiDirection</code> values indicate the text direction. |
| */ |
| enum UBiDiDirection { |
| /** @memo All left-to-right text. This is a 0 value. */ |
| UBIDI_LTR, |
| /** @memo All right-to-left text. This is a 1 value. */ |
| UBIDI_RTL, |
| /** @memo Mixed-directional text. */ |
| UBIDI_MIXED |
| }; |
| |
| 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. |
| */ |
| struct UBiDi; |
| |
| 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_getLine()</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. |
| */ |
| CAPI UBiDi * U_EXPORT2 |
| ubidi_open(); |
| |
| /** |
| * 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. |
| */ |
| CAPI UBiDi * U_EXPORT2 |
| ubidi_openSized(UTextOffset maxLength, UTextOffset maxRunCount, UErrorCode *pErrorCode); |
| |
| /** |
| * <code>ubidi_close()</code> must be called to free the memory |
| * associated with a UBiDi object.<p> |
| * |
| * <strong>Important: </strong> |
| * If a <code>UBiDi</code> object is the <quote>child</quote> |
| * of another one (its <quote>parent</quote>), 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 |
| */ |
| CAPI void U_EXPORT2 |
| ubidi_close(UBiDi *pBiDi); |
| |
| /** |
| * Perform the Unicode BiDi algorithm. It is defined in the |
| * <a href="http://www.unicode.org/unicode/reports/tr9/">Unicode Technical Report 9</a>, |
| * version 5, |
| * also described in The Unicode Standard, Version 3.0 .<p> |
| * |
| * This function takes a single plain text paragraph with or without |
| * externally specified embedding levels from <quote>styled</quote> 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> |
| * |
| * @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. |
| */ |
| CAPI void U_EXPORT2 |
| ubidi_setPara(UBiDi *pBiDi, const UChar *text, UTextOffset length, |
| UBiDiLevel paraLevel, UBiDiLevel *embeddingLevels, |
| UErrorCode *pErrorCode); |
| |
| /** |
| * <code>ubidi_getLine()</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</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. |
| * |
| * @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 |
| */ |
| CAPI void U_EXPORT2 |
| ubidi_setLine(const UBiDi *pParaBiDi, |
| UTextOffset start, UTextOffset 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 |
| */ |
| CAPI UBiDiDirection U_EXPORT2 |
| ubidi_getDirection(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. |
| */ |
| CAPI UTextOffset 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 |
| */ |
| CAPI 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 |
| */ |
| CAPI UBiDiLevel U_EXPORT2 |
| ubidi_getLevelAt(const UBiDi *pBiDi, UTextOffset 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 |
| */ |
| CAPI const UBiDiLevel * U_EXPORT2 |
| ubidi_getLevels(UBiDi *pBiDi, UErrorCode *pErrorCode); |
| |
| /** |
| * Get a logical run. |
| * This function returns information about a run and is used |
| * to retrieve runs in logical order.<p> |
| * This is especially useful for line-breaking on a paragraph. |
| * |
| * @param pBiDi is the paragraph or line <code>UBiDi</code> object. |
| * |
| * @param 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. |
| */ |
| CAPI void U_EXPORT2 |
| ubidi_getLogicalRun(const UBiDi *pBiDi, UTextOffset logicalStart, |
| UTextOffset *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. |
| */ |
| CAPI UTextOffset 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> |
| * UTextOffset 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); |
| * } |
| * } |
| * </pre> |
| * |
| * Note that in right-to-left runs, code like this places |
| * modifier letters before base characters and second surrogates |
| * before first ones. |
| */ |
| CAPI UBiDiDirection U_EXPORT2 |
| ubidi_getVisualRun(UBiDi *pBiDi, UTextOffset runIndex, |
| UTextOffset *pLogicalStart, UTextOffset *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 |
| */ |
| CAPI UTextOffset U_EXPORT2 |
| ubidi_getVisualIndex(UBiDi *pBiDi, UTextOffset 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 |
| */ |
| CAPI UTextOffset U_EXPORT2 |
| ubidi_getLogicalIndex(UBiDi *pBiDi, UTextOffset 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 |
| */ |
| CAPI void U_EXPORT2 |
| ubidi_getLogicalMap(UBiDi *pBiDi, UTextOffset *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 |
| */ |
| CAPI void U_EXPORT2 |
| ubidi_getVisualMap(UBiDi *pBiDi, UTextOffset *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>. |
| */ |
| CAPI void U_EXPORT2 |
| ubidi_reorderLogical(const UBiDiLevel *levels, UTextOffset length, UTextOffset *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>. |
| */ |
| CAPI void U_EXPORT2 |
| ubidi_reorderVisual(const UBiDiLevel *levels, UTextOffset length, UTextOffset *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. |
| */ |
| CAPI void U_EXPORT2 |
| ubidi_invertMap(const UTextOffset *srcMap, UTextOffset *destMap, UTextOffset length); |
| |
| /** |
| * @name Sample code for the ICU BiDi API |
| * |
| * <h2>Rendering a paragraph with the ICU BiDi API</h2> |
| * |
| * 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> |
| * #include "ubidi.h" |
| * |
| * typedef enum { |
| * styleNormal=0, styleSelected=1, |
| * styleBold=2, styleItalics=4, |
| * styleSuper=8, styleSub=16 |
| * } Style; |
| * |
| * typedef struct { UTextOffset limit; Style style; } StyleRun; |
| * |
| * int getTextWidth(const UChar *text, UTextOffset start, UTextOffset 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, UTextOffset start, UTextOffset *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, UTextOffset start, UTextOffset 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, |
| * UTextOffset start, UTextOffset 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, |
| * UTextOffset start, UTextOffset 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 |
| * UTextOffset count, i, length; |
| * UBiDiLevel level; |
| * |
| * count=ubidi_countRuns(para, pErrorCode); |
| * if(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 { |
| * UTextOffset 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, UTextOffset length, |
| * UBiDiDirection textDirection, |
| * const StyleRun *styleRuns, int styleRunCount, |
| * int lineWidth, |
| * UErrorCode *pErrorCode) { |
| * UBiDi *para; |
| * |
| * if(pErrorCode==NULL || 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(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) { |
| * UTextOffset 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(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); |
| * } |
| * </pre> |
| */ |
| BIDI_SAMPLE_CODE |
| /*@{*/ |
| /*@}*/ |
| |
| /*@}*/ |
| |
| #endif |