SetPara().
- */
- nsBidi() { mBiDi = ubidi_open(); }
-
- /** @brief Destructor. */
- ~nsBidi() { ubidi_close(mBiDi); }
-
- /**
- * Perform the Unicode Bidi algorithm.
- *
- * @param aText is a pointer to the single-paragraph text that the
- * Bidi algorithm will be performed on
- * (step (P1) of the algorithm is performed externally).
- * The text must be (at least) aLength long.
- *
- *
- * @param aLength is the length of the text; if aLength==-1 then
- * the text must be zero-terminated.
- *
- * @param aParaLevel 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 aParaLevel can be set to
- * either NSBIDI_DEFAULT_LTR
- * or NSBIDI_DEFAULT_RTL;
- * 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 NSBIDI_MAX_EXPLICIT_LEVEL
- * is also valid, with odd levels indicating RTL.
- */
- nsresult SetPara(const char16_t* aText, int32_t aLength,
- nsBidiLevel aParaLevel) {
- UErrorCode error = U_ZERO_ERROR;
- ubidi_setPara(mBiDi, reinterpret_castNSBIDI_XXX value that indicates
- * if the entire text represented by this object is unidirectional,
- * and which direction, or if it is mixed-directional.
- *
- * @see nsBidiDirection
- */
- nsBidiDirection GetDirection() {
- return nsBidiDirection(ubidi_getDirection(mBiDi));
- }
-
- /**
- * Get the paragraph level of the text.
- *
- * @param aParaLevel receives a NSBIDI_XXX value indicating
- * the paragraph level
- *
- * @see nsBidiLevel
- */
- nsBidiLevel GetParaLevel() { return ubidi_getParaLevel(mBiDi); }
-
- /**
- * 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.
- * CountRuns should be called before this.
- * before the runs are retrieved.
- *
- * @param aLogicalStart is the first character of the run.
- *
- * @param aLogicalLimit 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
- * aLogicalStart.
- * This pointer cannot be nullptr.
- *
- * @param aLevel will receive the level of the run.
- * This pointer cannot be nullptr.
- */
- void GetLogicalRun(int32_t aLogicalStart, int32_t* aLogicalLimit,
- nsBidiLevel* aLevel);
-
- /**
- * Get the number of runs.
- * This function may invoke the actual reordering on the
- * nsBidi object, after SetPara
- * may have resolved only the levels of the text. Therefore,
- * CountRuns may have to allocate memory,
- * and may fail doing so.
- *
- * @param aRunCount will receive the number of runs.
- */
- nsresult CountRuns(int32_t* aRunCount);
-
- /**
- * 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.
- * CountRuns should be called
- * before the runs are retrieved.
- *
- * @param aRunIndex is the number of the run in visual order, in the
- * range [0..CountRuns-1].
- *
- * @param aLogicalStart is the first logical character index in the text.
- * The pointer may be nullptr if this index is not needed.
- *
- * @param aLength is the number of characters (at least one) in the run.
- * The pointer may be nullptr if this is not needed.
- *
- * @returns the directionality of the run,
- * NSBIDI_LTR==0 or NSBIDI_RTL==1,
- * never NSBIDI_MIXED.
- *
- * @see CountRuns
- *
- * Example:
- * @code
- * int32_t i, count, logicalStart, visualIndex=0, length;
- * nsBidiDirection dir;
- * pBidi->CountRuns(&count);
- * for(i=0; i
- * The index map will result in
- * GetVisualMap on a
- * nsBidi object.
- *
- * @param aLevels is an array with aLength levels that have been
- * determined by the application.
- *
- * @param aLength is the number of levels in the array, or, semantically,
- * the number of objects to be reordered.
- * It must be aLength>0.
- *
- * @param aIndexMap is a pointer to an array of aLength
- * indexes which will reflect the reordering of the characters.
- * The array does not need to be initialized.aIndexMap[aVisualIndex]==aLogicalIndex.
- */
- static void ReorderVisual(const nsBidiLevel* aLevels, int32_t aLength,
- int32_t* aIndexMap) {
- ubidi_reorderVisual(aLevels, aLength, aIndexMap);
- }
-
- private:
- nsBidi(const nsBidi&) = delete;
- void operator=(const nsBidi&) = delete;
-
- UBiDi* mBiDi;
- // The two fields below are updated when CountRuns is called.
- const nsBidiLevel* mLevels = nullptr;
- int32_t mLength = 0;
-};
-
-#endif // _nsBidi_h_