* *
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 */ 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
* pesudo-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
*/
typedef uint8_t UBiDiLevel;
/** Paragraph level setting.
* If there is no strong character, then set the paragraph level to 0 (left-to-right).
*/
#define UBIDI_DEFAULT_LTR 0xfe
/** Paragraph level setting.
* If there is no strong character, then set the paragraph level to 1 (right-to-left).
*/
#define UBIDI_DEFAULT_RTL 0xff
/**
* Maximum explicit embedding level.
* (The maximum resolved level can be up to UBIDI_MAX_EXPLICIT_LEVEL+1).
*
*/
#define UBIDI_MAX_EXPLICIT_LEVEL 61
/** Bit flag for level input.
* Overrides directional properties.
*/
#define UBIDI_LEVEL_OVERRIDE 0x80
/**
* @memo UBiDiDirection 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 UBiDi structure for the declaration of
* the API functions. Its fields are implementation-specific.
* This structure holds information about a paragraph of text * with BiDi-algorithm-related details, or about one line of * such a paragraph.
* 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 UBiDi structure.
* Such an object is initially empty. It is assigned
* the BiDi properties of a paragraph by ubidi_setPara()
* or the BiDi properties of a line of a paragraph by
* ubidi_setLine().
* This object can be reused for as long as it is not deallocated
* by calling ubidi_close().
* ubidi_set() will allocate additional memory for
* internal structures as necessary.
*
* @return An empty UBiDi object.
*/
U_CAPI 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 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.
* 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,
* which must not indicate a failure before the function call.
*
* @return An empty UBiDi object with preallocated memory.
*/
U_CAPI UBiDi * U_EXPORT2
ubidi_openSized(UTextOffset maxLength, UTextOffset maxRunCount, UErrorCode *pErrorCode);
/**
* ubidi_close() must be called to free the memory
* associated with a UBiDi object.
*
* Important:
* 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
*/
U_CAPI 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 codepages 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
*/
U_CAPI 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.
*
* @see ubidi_setInverse
*/
U_CAPI UBool U_EXPORT2
ubidi_isInverse(UBiDi *pBiDi);
/**
* Perform the Unicode BiDi algorithm. It is defined in the
* Unicode Technical Report 9,
* version 5,
* also described in The Unicode Standard, Version 3.0 .
*
* This function takes a single plain text paragraph with or without
* externally specified embedding levels from styled
text
* and computes the left-right-directionality of each character.
*
* 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.
* 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 must be externally split into separate paragraphs (rule P1).
* Paragraph separators (B) should appear at most at the very end.
*
* @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 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) 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 paragraph;
* 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 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 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.
* 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,
* which must not indicate a failure before the function call.
*/
U_CAPI void U_EXPORT2
ubidi_setPara(UBiDi *pBiDi, const UChar *text, UTextOffset 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 paragraph of text, and by specifying
* a range of indexes in this paragraph.
* In the new line object, the indexes will range from 0 to limit-start.
*
* This is used after calling ubidi_setPara()
* for a paragraph, and after line-breaking on that paragraph.
* It is not necessary if the 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.
*
* @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).
* It must be 0<=start<=limit<=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
*/
U_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 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
*/
U_CAPI 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
*/
U_CAPI 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.
*/
U_CAPI UTextOffset 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.
*
* @see UBiDiLevel
*/
U_CAPI UBiDiLevel U_EXPORT2
ubidi_getParaLevel(const UBiDi *pBiDi);
/**
* 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
*/
U_CAPI UBiDiLevel U_EXPORT2
ubidi_getLevelAt(const UBiDi *pBiDi, UTextOffset 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.
*
* @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 NULL if an error occurs.
*
* @see UBiDiLevel
*/
U_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.
* 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.
*/
U_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
* 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,
* which must not indicate a failure before the function call.
*
* @return The number of runs.
*/
U_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.
* 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:
*
* 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);
* }
* }
*
*
* Note that in right-to-left runs, code like this places
* modifier letters before base characters and second surrogates
* before first ones.
*/
U_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
* UBiDi object, then calling
* ubidi_getLogicalMap() is more efficient.
*
* 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 UBiDi 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
*/
U_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
* UBiDi object, then calling
* ubidi_getVisualMap() is more efficient.
*
* This is the inverse function to ubidi_getVisualIndex().
*
* @param pBiDi is the paragraph or line UBiDi 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
*/
U_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 UBiDi object.
*
* @param indexMap is a pointer to an array of ubidi_getLength()
* indexes which will reflect the reordering of the characters.
* The array does not need to be initialized.
* The index map will result in indexMap[logicalIndex]==visualIndex.
*
* @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
*/
U_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 UBiDi object.
*
* @param indexMap is a pointer to an array of ubidi_getLength()
* indexes which will reflect the reordering of the characters.
* The array does not need to be initialized.
* The index map will result in indexMap[visualIndex]==logicalIndex.
*
* @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
*/
U_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 ubidi_getLogicalMap on a
* UBiDi object.
*
* @param levels is an array with length 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 length>0.
*
* @param indexMap is a pointer to an array of length
* indexes which will reflect the reordering of the characters.
* The array does not need to be initialized.
* The index map will result in indexMap[logicalIndex]==visualIndex.
*/
U_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 ubidi_getVisualMap on a
* UBiDi object.
*
* @param levels is an array with length 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 length>0.
*
* @param indexMap is a pointer to an array of length
* indexes which will reflect the reordering of the characters.
* The array does not need to be initialized.
* The index map will result in indexMap[visualIndex]==logicalIndex.
*/
U_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 length indexes
* which define the original mapping.
*
* @param destMap is an array with length indexes
* which will be filled with the inverse mapping.
*
* @param length is the length of each array.
*/
U_CAPI void U_EXPORT2
ubidi_invertMap(const UTextOffset *srcMap, UTextOffset *destMap, UTextOffset length);
/** option flags for ubidi_writeReordered() */
/**
* option bit for ubidi_writeReordered():
* keep combining characters after their base characters in RTL runs
*
* @see ubidi_writeReordered
*/
#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
*/
#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
*/
#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
*/
#define UBIDI_REMOVE_BIDI_CONTROLS 8
/**
* option bit for ubidi_writeReordered():
* write the output in reverse order
*
*
This has the same effect as calling ubidi_writeReordered()
* first without this option, and then calling
* ubidi_writeReverse() 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.
UBiDi object containing the reordering
* information for one paragraph or line of text as set by
* ubidi_setPara() or ubidi_setLine() 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 destSize
* and options parameters and of the option bit flags.
*
* @param pBiDi A pointer to a UBiDi object that
* is set by ubidi_setPara() or
* ubidi_setLine() and contains the reordering
* information for the text that it was defined for,
* as well as a pointer to that text.
* The text was aliased (only the pointer was stored
* without copying the contents) and must not have been modified
* since the ubidi_setPara() call.
dest[destSize]
* must not overlap.
*
* @param destSize The size of the dest buffer,
* in number of UChars.
* If the UBIDI_INSERT_LRM_FOR_NUMERIC
* option is set, then the destination length could be
* as large as
* ubidi_getLength(pBiDi)+2*ubidi_countRuns(pBiDi).
* If the UBIDI_REMOVE_BIDI_CONTROLS option
* is set, then the destination length may be less than
* ubidi_getLength(pBiDi).
* If none of these options is set, then the destination length
* will be exactly ubidi_getLength(pBiDi).
*
* @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).
*
* @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 characters that were written to dest.
*/
U_CAPI UTextOffset 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 ubidi_writeReordered(). For detailed descriptions
* of the parameters, see there.
* Since no BiDi controls are inserted here, this function will never
* write more than srcLength characters to dest.
*
* @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.
* src[srcLength] and dest[destSize]
* must not overlap.
*
* @param destSize The size of the dest buffer,
* in number of UChars.
* If the UBIDI_REMOVE_BIDI_CONTROLS option
* is set, then the destination length may be less than
* srcLength.
* If this option is not set, then the destination length
* will be exactly srcLength.
*
* @param options A bit set of options for the reordering that control
* how the reordered text is written.
* See ubidi_writeReordered().
*
* @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 characters that were written to dest.
*/
U_CAPI UTextOffset U_EXPORT2
ubidi_writeReverse(const UChar *src, int32_t srcLength,
UChar *dest, int32_t destSize,
uint16_t options,
UErrorCode *pErrorCode);
/**
* @name Sample code for the ICU BIDI API
*
* The basic assumptions are:
*
* #include "unicode/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(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 {
* 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 || 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) {
* 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(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);
* }
*
*/
BIDI_SAMPLE_CODE
/*@{*/
/*@}*/
/*@}*/
#endif