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Value returned byUBiDiClassCallback callbacks when there is no need to override the standard Bidi class for a given code point.

This constant is deprecated; use u_getIntPropertyMaxValue(UCHAR_BIDI_CLASS)+1 instead.

See also

UBiDiClassCallback

Deprecated:

ICU 58 The numeric value may change over time, see ICU ticket #12420.

Definition at line1992 of fileubidi.h.

Paragraph level setting.

Constant indicating that the base direction depends on the first strong directional character in the text according to the Unicode Bidirectional Algorithm. If no strong directional character is present, then set the paragraph level to 0 (left-to-right).

If this value is used in conjunction with reordering modesUBIDI_REORDER_INVERSE_LIKE_DIRECT orUBIDI_REORDER_INVERSE_FOR_NUMBERS_SPECIAL, the text to reorder is assumed to be visual LTR, and the text after reordering is required to be the corresponding logical string with appropriate contextual direction. The direction of the result string will be RTL if either the righmost or leftmost strong character of the source text is RTL or Arabic Letter, the direction will be LTR otherwise.

If reordering optionUBIDI_OPTION_INSERT_MARKS is set, an RLM may be added at the beginning of the result string to ensure round trip (that the result string, when reordered back to visual, will produce the original source text).

See also

UBIDI_REORDER_INVERSE_LIKE_DIRECT

UBIDI_REORDER_INVERSE_FOR_NUMBERS_SPECIAL

Stable:

ICU 2.0

Definition at line366 of fileubidi.h.

Paragraph level setting.

Constant indicating that the base direction depends on the first strong directional character in the text according to the Unicode Bidirectional Algorithm. If no strong directional character is present, then set the paragraph level to 1 (right-to-left).

If this value is used in conjunction with reordering modesUBIDI_REORDER_INVERSE_LIKE_DIRECT orUBIDI_REORDER_INVERSE_FOR_NUMBERS_SPECIAL, the text to reorder is assumed to be visual LTR, and the text after reordering is required to be the corresponding logical string with appropriate contextual direction. The direction of the result string will be RTL if either the righmost or leftmost strong character of the source text is RTL or Arabic Letter, or if the text contains no strong character; the direction will be LTR otherwise.

If reordering optionUBIDI_OPTION_INSERT_MARKS is set, an RLM may be added at the beginning of the result string to ensure round trip (that the result string, when reordered back to visual, will produce the original source text).

See also

UBIDI_REORDER_INVERSE_LIKE_DIRECT

UBIDI_REORDER_INVERSE_FOR_NUMBERS_SPECIAL

Stable:

ICU 2.0

Definition at line393 of fileubidi.h.

option bit forubidi_writeReordered(): replace characters with the "mirrored" property in RTL runs by their mirror-image mappings

See also

ubidi_writeReordered

Stable:

ICU 2.0

Definition at line1864 of fileubidi.h.

option bit forubidi_writeReordered(): surround the run with LRMs if necessary; this is part of the approximate "inverse Bidi" algorithm

This option does not imply corresponding adjustment of the index mappings.

See also

ubidi_setInverse

ubidi_writeReordered

Stable:

ICU 2.0

Definition at line1878 of fileubidi.h.

option flags forubidi_writeReordered()

option bit forubidi_writeReordered(): keep combining characters after their base characters in RTL runs

See also

ubidi_writeReordered

Stable:

ICU 2.0

Definition at line1854 of fileubidi.h.

Bit flag for level input.

Overrides directional properties.

Stable:

ICU 2.0

Definition at line408 of fileubidi.h.

Special value which can be returned by the mapping functions when a logical index has no corresponding visual index or vice-versa.

This may happen for the logical-to-visual mapping of a Bidi control when optionUBIDI_OPTION_REMOVE_CONTROLS is specified. This can also happen for the visual-to-logical mapping of a Bidi mark (LRM or RLM) inserted by optionUBIDI_OPTION_INSERT_MARKS.

See also

ubidi_getVisualIndex

ubidi_getVisualMap

ubidi_getLogicalIndex

ubidi_getLogicalMap

Stable:

ICU 3.6

Definition at line423 of fileubidi.h.

Maximum explicit embedding level.

Same as the max_depth value in theUnicode Bidirectional Algorithm. (The maximum resolved level can be up toUBIDI_MAX_EXPLICIT_LEVEL+1).

Stable:

ICU 2.0

Definition at line402 of fileubidi.h.

option bit forubidi_writeReordered(): write the output in reverse order

This has the same effect as callingubidi_writeReordered() first without this option, and then callingubidi_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.

See also

ubidi_writeReordered

Stable:

ICU 2.0

Definition at line1907 of fileubidi.h.

option bit forubidi_writeReordered(): remove Bidi control characters (this does not affectUBIDI_INSERT_LRM_FOR_NUMERIC)

This option does not imply corresponding adjustment of the index mappings.

See also

ubidi_writeReordered

Stable:

ICU 2.0

Definition at line1891 of fileubidi.h.

Stable:

ICU 2.0

Definition at line340 of fileubidi.h.

Callback type declaration for overriding default Bidi class values with custom ones.

Usually, the function pointer will be propagated to aUBiDi object by calling theubidi_setClassCallback() function; then the callback will be invoked by the UBA implementation any time the class of a character is to be determined.

Parameters

context	is a pointer to the callback private data.
c	is the code point to get a Bidi class for.

Returns

The directional property / Bidi class for the given code pointc if the default class has been overridden, oru_getIntPropertyMaxValue(UCHAR_BIDI_CLASS)+1 if the standard Bidi class value forc is to be used.

See also

ubidi_setClassCallback

ubidi_getClassCallback

Stable:

ICU 3.6

Definition at line2016 of fileubidi.h.

Stable:

ICU 2.0

Definition at line340 of fileubidi.h.

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 theparaLevel andembeddingLevels arguments ofubidi_setPara(); there:

• bit 7 of anembeddingLevels[] value indicates whether the using application is specifying the level of a character tooverride whatever the Bidi implementation would resolve it to.
• paraLevel can be set to the pseudo-level valuesUBIDI_DEFAULT_LTR andUBIDI_DEFAULT_RTL.

See also

ubidi_setPara

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 theubidi_setPara() function shall determine it but there is no strongly typed character in the input.

Note that the value forUBIDI_DEFAULT_LTR is even and the one forUBIDI_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.

Note: The numeric values of the related constants will not change: They are tied to the use of 7-bit byte values (plus the override bit) and of the UBiDiLevel=uint8_t data type in this API.

See also

UBIDI_DEFAULT_LTR

UBIDI_DEFAULT_RTL

UBIDI_LEVEL_OVERRIDE

UBIDI_MAX_EXPLICIT_LEVEL

Stable:

ICU 2.0

Definition at line340 of fileubidi.h.

UBiDiReorderingMode values indicate which variant of the Bidi algorithm to use.

See also

ubidi_setReorderingMode

Stable:

ICU 3.6

UBiDiReorderingOption values indicate which options are specified to affect the Bidi algorithm.

See also

ubidi_setReorderingOptions

Stable:

ICU 3.6

UBiDiDirection values indicate the text direction.

Stable:

ICU 2.0

Definition at line429 of fileubidi.h.

UBiDiReorderingMode values indicate which variant of the Bidi algorithm to use.

See also

ubidi_setReorderingMode

Stable:

ICU 3.6

Definition at line699 of fileubidi.h.

UBiDiReorderingOption values indicate which options are specified to affect the Bidi algorithm.

See also

ubidi_setReorderingOptions

Stable:

ICU 3.6

Definition at line914 of fileubidi.h.

ubidi_close() must be called to free the memory associated with a UBiDi object.

Important: A parentUBiDi object must not be destroyed or reused if it still has children. If aUBiDi object has become thechild of another one (itsparent) by callingubidi_setLine(), then the child object must be destroyed (closed) or reused (by callingubidi_setPara() orubidi_setLine()) before the parent object.

Parameters

pBiDi

is aUBiDi object.

See also

ubidi_setPara

ubidi_setLine

Stable:

ICU 2.0

Get the number of paragraphs.

Parameters

pBiDi

is the paragraph or lineUBiDi object.

Returns

The number of paragraphs.

Stable:

ICU 3.4

Get the number of runs.

This function may invoke the actual reordering on theUBiDi object, afterubidi_setPara() may have resolved only the levels of the text. Therefore,ubidi_countRuns() may have to allocate memory, and may fail doing so.

Parameters

pBiDi	is the paragraph or lineUBiDi object.
pErrorCode	must be a valid pointer to an error code value.

Returns

The number of runs.

Stable:

ICU 2.0

Gets the base direction of the text provided according to the Unicode Bidirectional Algorithm.

The base direction is derived from the first character in the string with bidirectional character type L, R, or AL. If the first such character has type L,UBIDI_LTR is returned. If the first such character has type R or AL,UBIDI_RTL is returned. If the string does not contain any character of these types, thenUBIDI_NEUTRAL is returned.

This is a lightweight function for use when only the base direction is needed and no further bidi processing of the text is needed.

Parameters

text	is a pointer to the text whose base direction is needed. Note: the text must be (at least)length long.
length	is the length of the text; iflength==-1 then the text must be zero-terminated.

Returns

UBIDI_LTR,UBIDI_RTL,UBIDI_NEUTRAL

See also

UBiDiDirection

Stable:

ICU 4.6

Get the current callback function used for Bidi class determination.

Parameters

pBiDi	is the paragraphUBiDi object.
fn	fillin: Returns the callback function pointer.
context	fillin: Returns the callback's private context.

See also

ubidi_setClassCallback

Stable:

ICU 3.6

Retrieve the Bidi class for a given code point.

If aUBiDiClassCallback callback is defined and returns a value other thanu_getIntPropertyMaxValue(UCHAR_BIDI_CLASS)+1, that value is used; otherwise the default class determination mechanism is invoked.

Parameters

pBiDi	is the paragraphUBiDi object.
c	is the code point whose Bidi class must be retrieved.

Returns

The Bidi class for characterc based on the givenpBiDi instance.

See also

UBiDiClassCallback

Stable:

ICU 3.6

Get the directionality of the text.

Parameters

pBiDi

is the paragraph or lineUBiDi object.

Returns

a value ofUBIDI_LTR,UBIDI_RTL orUBIDI_MIXED that indicates if the entire text represented by this object is unidirectional, and which direction, or if it is mixed-directional. Note - The valueUBIDI_NEUTRAL is never returned from this method.

See also

UBiDiDirection

Stable:

ICU 2.0

Referenced byicu::ParagraphLayout::getTextDirection().

Get the length of the text.

Parameters

pBiDi

is the paragraph or lineUBiDi object.

Returns

The length of the text that the UBiDi object was created for.

Stable:

ICU 2.0

Get the level for one character.

Parameters

pBiDi	is the paragraph or lineUBiDi object.
charIndex	the index of a character. It must be in the range [0..ubidi_getProcessedLength(pBiDi)].

Returns

The level for the character at charIndex (0 if charIndex is not in the valid range).

See also

UBiDiLevel

ubidi_getProcessedLength

Stable:

ICU 2.0

Get an array of levels for each character.

Note that this function may allocate memory under some circumstances, unlikeubidi_getLevelAt().

Parameters

pBiDi	is the paragraph or lineUBiDi object, whose text length must be strictly positive.
pErrorCode	must be a valid pointer to an error code value.

Returns

The levels array for the text, orNULL if an error occurs.

See also

UBiDiLevel

ubidi_getProcessedLength

Stable:

ICU 2.0

Get the logical text position from a visual position.

If such a mapping is used many times on the sameUBiDi object, then callingubidi_getVisualMap() is more efficient.

The value returned may beUBIDI_MAP_NOWHERE if there is no logical position because the corresponding text character is a Bidi mark inserted in the output by optionUBIDI_OPTION_INSERT_MARKS.

This is the inverse function toubidi_getVisualIndex().

When the visual output is altered by using options ofubidi_writeReordered() such asUBIDI_INSERT_LRM_FOR_NUMERIC,UBIDI_KEEP_BASE_COMBINING,UBIDI_OUTPUT_REVERSE,UBIDI_REMOVE_BIDI_CONTROLS, the logical position returned may not be correct. It is advised to use, when possible, reordering options such asUBIDI_OPTION_INSERT_MARKS andUBIDI_OPTION_REMOVE_CONTROLS.

Parameters

pBiDi	is the paragraph or lineUBiDi object.
visualIndex	is the visual position of a character.
pErrorCode	must be a valid pointer to an error code value.

Returns

The index of this character in the text.

See also

ubidi_getVisualMap

ubidi_getVisualIndex

ubidi_getResultLength

Stable:

ICU 2.0

Get a logical-to-visual index map (array) for the characters in the UBiDi (paragraph or line) object.

Some values in the map may beUBIDI_MAP_NOWHERE if the corresponding text characters are Bidi controls removed from the visual output by the optionUBIDI_OPTION_REMOVE_CONTROLS.

When the visual output is altered by using options ofubidi_writeReordered() such asUBIDI_INSERT_LRM_FOR_NUMERIC,UBIDI_KEEP_BASE_COMBINING,UBIDI_OUTPUT_REVERSE,UBIDI_REMOVE_BIDI_CONTROLS, the visual positions returned may not be correct. It is advised to use, when possible, reordering options such asUBIDI_OPTION_INSERT_MARKS andUBIDI_OPTION_REMOVE_CONTROLS.

Note that in right-to-left runs, this mapping places second surrogates before first ones (which is generally a bad idea) and combining characters before base characters. Use ofubidi_writeReordered(), optionally with theUBIDI_KEEP_BASE_COMBINING option can be considered instead of using the mapping, in order to avoid these issues.

Parameters

pBiDi	is the paragraph or lineUBiDi object.
indexMap	is a pointer to an array ofubidi_getProcessedLength() indexes which will reflect the reordering of the characters. If optionUBIDI_OPTION_INSERT_MARKS is set, the number of elements allocated inindexMap must be no less thanubidi_getResultLength(). The array does not need to be initialized. The index map will result inindexMap[logicalIndex]==visualIndex.
pErrorCode	must be a valid pointer to an error code value.

See also

ubidi_getVisualMap

ubidi_getVisualIndex

ubidi_getProcessedLength

ubidi_getResultLength

Stable:

ICU 2.0

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.

Parameters

pBiDi	is the paragraph or lineUBiDi object.
logicalPosition	is a logical position within the source text.
pLogicalLimit	will receive the limit of the corresponding run. The l-value that you point to here may be the same expression (variable) as the one forlogicalPosition. This pointer can beNULL if this value is not necessary.
pLevel	will receive the level of the corresponding run. This pointer can beNULL if this value is not necessary.

See also

ubidi_getProcessedLength

Stable:

ICU 2.0

Get a paragraph, given a position within the text.

This function returns information about a paragraph.
Note: if the paragraph index is known, it is more efficient to retrieve the paragraph information usingubidi_getParagraphByIndex().

Parameters

pBiDi	is the paragraph or lineUBiDi object.
charIndex	is the index of a character within the text, in the range[0..ubidi_getProcessedLength(pBiDi)-1].
pParaStart	will receive the index of the first character of the paragraph in the text. This pointer can beNULL if this value is not necessary.
pParaLimit	will receive the limit of the paragraph. The l-value that you point to here may be the same expression (variable) as the one forcharIndex. This pointer can beNULL if this value is not necessary.
pParaLevel	will receive the level of the paragraph. This pointer can beNULL if this value is not necessary.
pErrorCode	must be a valid pointer to an error code value.

Returns

The index of the paragraph containing the specified position.

See also

ubidi_getProcessedLength

Stable:

ICU 3.4

Get a paragraph, given the index of this paragraph.

This function returns information about a paragraph.

Parameters

pBiDi	is the paragraphUBiDi object.
paraIndex	is the number of the paragraph, in the range[0..ubidi_countParagraphs(pBiDi)-1].
pParaStart	will receive the index of the first character of the paragraph in the text. This pointer can beNULL if this value is not necessary.
pParaLimit	will receive the limit of the paragraph. This pointer can beNULL if this value is not necessary.
pParaLevel	will receive the level of the paragraph. This pointer can beNULL if this value is not necessary.
pErrorCode	must be a valid pointer to an error code value.

Stable:

ICU 3.4

Get the paragraph level of the text.

Parameters

pBiDi

is the paragraph or lineUBiDi object.

Returns

The paragraph level. If there are multiple paragraphs, their level may vary if the required paraLevel is UBIDI_DEFAULT_LTR or UBIDI_DEFAULT_RTL. In that case, the level of the first paragraph is returned.

See also

UBiDiLevel

ubidi_getParagraph

ubidi_getParagraphByIndex

Stable:

ICU 2.0

Referenced byicu::ParagraphLayout::getParagraphLevel().

Get the length of the source text processed by the last call toubidi_setPara().

This length may be different from the length of the source text if optionUBIDI_OPTION_STREAMING has been set.
Note that whenever the length of the text affects the execution or the result of a function, it is the processed length which must be considered, except forubidi_setPara (which receives unprocessed source text) andubidi_getLength (which returns the original length of the source text).
In particular, the processed length is the one to consider in the following cases:

• maximum value of thelimit argument ofubidi_setLine
• maximum value of thecharIndex argument ofubidi_getParagraph
• maximum value of thecharIndex argument ofubidi_getLevelAt
• number of elements in the array returned byubidi_getLevels
• maximum value of thelogicalStart argument ofubidi_getLogicalRun
• maximum value of thelogicalIndex argument ofubidi_getVisualIndex
• number of elements filled in the*indexMap argument ofubidi_getLogicalMap
• length of text processed byubidi_writeReordered

Parameters

pBiDi

is the paragraphUBiDi object.

Returns

The length of the part of the source text processed by the last call toubidi_setPara.

See also

ubidi_setPara

UBIDI_OPTION_STREAMING

Stable:

ICU 3.6

What is the requested reordering mode for a given Bidi object?

Parameters

pBiDi

is aUBiDi object.

Returns

the current reordering mode of the Bidi object

See also

ubidi_setReorderingMode

Stable:

ICU 3.6

What are the reordering options applied to a given Bidi object?

Parameters

pBiDi

is aUBiDi object.

Returns

the current reordering options of the Bidi object

See also

ubidi_setReorderingOptions

Stable:

ICU 3.6

Get the length of the reordered text resulting from the last call toubidi_setPara().

This length may be different from the length of the source text if optionUBIDI_OPTION_INSERT_MARKS or optionUBIDI_OPTION_REMOVE_CONTROLS has been set.
This resulting length is the one to consider in the following cases:

• maximum value of thevisualIndex argument ofubidi_getLogicalIndex
• number of elements of the*indexMap argument ofubidi_getVisualMap

Note that this length stays identical to the source text length if Bidi marks are inserted or removed using option bits ofubidi_writeReordered, or if optionUBIDI_REORDER_INVERSE_NUMBERS_AS_L has been set.

Parameters

pBiDi

is the paragraphUBiDi object.

Returns

The length of the reordered text resulting from the last call toubidi_setPara.

See also

ubidi_setPara

UBIDI_OPTION_INSERT_MARKS

UBIDI_OPTION_REMOVE_CONTROLS

Stable:

ICU 3.6

Get the pointer to the text.

Parameters

pBiDi

is the paragraph or lineUBiDi object.

Returns

The pointer to the text that the UBiDi object was created for.

See also

ubidi_setPara

ubidi_setLine

Stable:

ICU 2.0

Get the visual position from a logical text position.

If such a mapping is used many times on the sameUBiDi object, then callingubidi_getLogicalMap() is more efficient.

The value returned may beUBIDI_MAP_NOWHERE if there is no visual position because the corresponding text character is a Bidi control removed from output by the optionUBIDI_OPTION_REMOVE_CONTROLS.

When the visual output is altered by using options ofubidi_writeReordered() such asUBIDI_INSERT_LRM_FOR_NUMERIC,UBIDI_KEEP_BASE_COMBINING,UBIDI_OUTPUT_REVERSE,UBIDI_REMOVE_BIDI_CONTROLS, the visual position returned may not be correct. It is advised to use, when possible, reordering options such asUBIDI_OPTION_INSERT_MARKS andUBIDI_OPTION_REMOVE_CONTROLS.

Note that in right-to-left runs, this mapping places second surrogates before first ones (which is generally a bad idea) and combining characters before base characters. Use ofubidi_writeReordered(), optionally with theUBIDI_KEEP_BASE_COMBINING option can be considered instead of using the mapping, in order to avoid these issues.

Parameters

pBiDi	is the paragraph or lineUBiDi object.
logicalIndex	is the index of a character in the text.
pErrorCode	must be a valid pointer to an error code value.

Returns

The visual position of this character.

See also

ubidi_getLogicalMap

ubidi_getLogicalIndex

ubidi_getProcessedLength

Stable:

ICU 2.0

Get a visual-to-logical index map (array) for the characters in the UBiDi (paragraph or line) object.

Some values in the map may beUBIDI_MAP_NOWHERE if the corresponding text characters are Bidi marks inserted in the visual output by the optionUBIDI_OPTION_INSERT_MARKS.

When the visual output is altered by using options ofubidi_writeReordered() such asUBIDI_INSERT_LRM_FOR_NUMERIC,UBIDI_KEEP_BASE_COMBINING,UBIDI_OUTPUT_REVERSE,UBIDI_REMOVE_BIDI_CONTROLS, the logical positions returned may not be correct. It is advised to use, when possible, reordering options such asUBIDI_OPTION_INSERT_MARKS andUBIDI_OPTION_REMOVE_CONTROLS.

Parameters

pBiDi	is the paragraph or lineUBiDi object.
indexMap	is a pointer to an array ofubidi_getResultLength() indexes which will reflect the reordering of the characters. If optionUBIDI_OPTION_REMOVE_CONTROLS is set, the number of elements allocated inindexMap must be no less thanubidi_getProcessedLength(). The array does not need to be initialized. The index map will result inindexMap[visualIndex]==logicalIndex.
pErrorCode	must be a valid pointer to an error code value.

See also

ubidi_getLogicalMap

ubidi_getLogicalIndex

ubidi_getProcessedLength

ubidi_getResultLength

Stable:

ICU 2.0

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.

Parameters

pBiDi	is the paragraph or lineUBiDi object.
runIndex	is the number of the run in visual order, in the range[0..ubidi_countRuns(pBiDi)-1].
pLogicalStart	is the first logical character index in the text. The pointer may beNULL if this index is not needed.
pLength	is the number of characters (at least one) in the run. The pointer may beNULL if this is not needed.

Returns

the directionality of the run,UBIDI_LTR==0 orUBIDI_RTL==1, neverUBIDI_MIXED, neverUBIDI_NEUTRAL.

See also

ubidi_countRuns

Example:

  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);
      }
  }
*

Note that in right-to-left runs, code like this places second surrogates before first ones (which is generally a bad idea) and combining characters before base characters.

Use ofubidi_writeReordered(), optionally with theUBIDI_KEEP_BASE_COMBINING option, can be considered in order to avoid these issues.

Stable:

ICU 2.0

Invert an index map.

The index mapping of the first map is inverted and written to the second one.

Parameters

srcMap	is an array withlength elements which defines the original mapping from a source array containinglength elements to a destination array. Some elements of the source array may have no mapping in the destination array. In that case, their value will be the special valueUBIDI_MAP_NOWHERE. All elements must be >=0 or equal toUBIDI_MAP_NOWHERE. Some elements may have a value >=length, if the destination array has more elements than the source array. There must be no duplicate indexes (two or more elements with the same value exceptUBIDI_MAP_NOWHERE).
destMap	is an array with a number of elements equal to 1 + the highest value insrcMap.destMap will be filled with the inverse mapping. If element with index i insrcMap has a value k different fromUBIDI_MAP_NOWHERE, this means that element i of the source array maps to element k in the destination array. The inverse map will have value i in its k-th element. For all elements of the destination array which do not map to an element in the source array, the corresponding element in the inverse map will have a value equal toUBIDI_MAP_NOWHERE.
length	is the length of each array.

See also

UBIDI_MAP_NOWHERE

Stable:

ICU 2.0

Is this Bidi object set to perform the inverse Bidi algorithm?

Note: calling this function after setting the reordering mode withubidi_setReorderingMode will returntrue if the reordering mode was set toUBIDI_REORDER_INVERSE_NUMBERS_AS_L,false for all other values.

Parameters

pBiDi

is aUBiDi object.

Returns

true if the Bidi object is set to perform the inverse Bidi algorithm by handling numbers as L.

See also

ubidi_setInverse

ubidi_setReorderingMode

Stable:

ICU 2.0

Is this Bidi object set to allocate level 0 to block separators so that successive paragraphs progress from left to right?

Parameters

pBiDi

is aUBiDi object.

Returns

true if the Bidi object is set to allocate level 0 to block separators.

See also

ubidi_orderParagraphsLTR

Stable:

ICU 3.4

Allocate aUBiDi structure.

Such an object is initially empty. It is assigned the Bidi properties of a piece of text containing one or more paragraphs byubidi_setPara() or the Bidi properties of a line within a paragraph byubidi_setLine().

This object can be reused for as long as it is not deallocated by callingubidi_close().

ubidi_setPara() andubidi_setLine() will allocate additional memory for internal structures as necessary.

Returns

An emptyUBiDi object.

Stable:

ICU 2.0

Allocate aUBiDi structure with preallocated memory for internal structures.

This function provides aUBiDi object likeubidi_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 tomaxLength (the only failproof value) to avoid wasting memory, thenmaxRunCount could be set to 0 here and the internal structures that are associated with it will be allocated on demand, just like withubidi_open().

Parameters

maxLength	is the maximum text or line length that internal memory will be preallocated for. An attempt to associate this object with a longer text will fail, unless this value is 0, which leaves the allocation up to the implementation.
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 andmaxLength. It is typically small.
pErrorCode	must be a valid pointer to an error code value.

Returns

An emptyUBiDi object with preallocated memory.

Stable:

ICU 2.0

Specify whether block separators must be allocated level zero, so that successive paragraphs will progress from left to right.

This function must be called beforeubidi_setPara(). Paragraph separators (B) may appear in the text. Setting them to level zero means that all paragraph separators (including one possibly appearing in the last text position) are kept in the reordered text after the text that they follow in the source text. When this feature is not enabled, a paragraph separator at the last position of the text before reordering will go to the first position of the reordered text when the paragraph level is odd.

Parameters

pBiDi	is aUBiDi object.
orderParagraphsLTR	specifies whether paragraph separators (B) must receive level 0, so that successive paragraphs progress from left to right.

See also

ubidi_setPara

Stable:

ICU 3.4

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 usingubidi_getLogicalMap() on aUBiDi object.

Parameters

levels	is an array withlength levels that have been determined by the application.
length	is the number of levels in the array, or, semantically, the number of objects to be reordered. It must belength>0.
indexMap	is a pointer to an array oflength indexes which will reflect the reordering of the characters. The array does not need to be initialized.

The index map will result inindexMap[logicalIndex]==visualIndex.

Stable:

ICU 2.0

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 usingubidi_getVisualMap() on aUBiDi object.

Parameters

levels	is an array withlength levels that have been determined by the application.
length	is the number of levels in the array, or, semantically, the number of objects to be reordered. It must belength>0.
indexMap	is a pointer to an array oflength indexes which will reflect the reordering of the characters. The array does not need to be initialized.

The index map will result inindexMap[visualIndex]==logicalIndex.

Stable:

ICU 2.0

Set the callback function and callback data used by the UBA implementation for Bidi class determination.

This may be useful for assigning Bidi classes to PUA characters, or for special application needs. For instance, an application may want to handle all spaces like L or R characters (according to the base direction) when creating the visual ordering of logical lines which are part of a report organized in columns: there should not be interaction between adjacent cells.

Parameters

pBiDi	is the paragraphUBiDi object.
newFn	is the new callback function pointer.
newContext	is the new callback context pointer. This can be NULL.
oldFn	fillin: Returns the old callback function pointer. This can be NULL.
oldContext	fillin: Returns the old callback's context. This can be NULL.
pErrorCode	must be a valid pointer to an error code value.

See also

ubidi_getClassCallback

Stable:

ICU 3.6

Set the context before a call toubidi_setPara().

ubidi_setPara() computes the left-right directionality for a given piece of text which is supplied as one of its arguments. Sometimes this piece of text (the "main text") should be considered in context, because text appearing before ("prologue") and/or after ("epilogue") the main text may affect the result of this computation.

This function specifies the prologue and/or the epilogue for the next call toubidi_setPara(). The characters specified as prologue and epilogue should not be modified by the calling program until the call toubidi_setPara() has returned. If successive calls toubidi_setPara() all need specification of a context,ubidi_setContext() must be called before each call toubidi_setPara(). In other words, a context is not "remembered" after the following successful call toubidi_setPara().

If a call toubidi_setPara() specifies UBIDI_DEFAULT_LTR or UBIDI_DEFAULT_RTL as paraLevel and is preceded by a call toubidi_setContext() which specifies a prologue, the paragraph level will be computed taking in consideration the text in the prologue.

Whenubidi_setPara() is called without a previous call to ubidi_setContext, the main text is handled as if preceded and followed by strong directional characters at the current paragraph level. Callingubidi_setContext() with specification of a prologue will change this behavior by handling the main text as if preceded by the last strong character appearing in the prologue, if any. Callingubidi_setContext() with specification of an epilogue will change the behavior ofubidi_setPara() by handling the main text as if followed by the first strong character or digit appearing in the epilogue, if any.

Note 1: ifubidi_setContext is called repeatedly without callingubidi_setPara, the earlier calls have no effect, only the last call will be remembered for the next call toubidi_setPara.

Note 2: callingubidi_setContext(pBiDi, NULL, 0, NULL, 0, &errorCode) cancels any previous setting of non-empty prologue or epilogue. The next call toubidi_setPara() will process no prologue or epilogue.

Note 3: users must be aware that even after setting the context before a call toubidi_setPara() to perform e.g. a logical to visual transformation, the resulting string may not be identical to what it would have been if all the text, including prologue and epilogue, had been processed together.
Example (upper case letters represent RTL characters):
  prologue = "<code>abc DE</code>"
  epilogue = none
  main text = "<code>FGH xyz</code>"
  paraLevel = UBIDI_LTR
  display without prologue = "<code>HGF xyz</code>" ("HGF" is adjacent to "xyz")
  display with prologue = "<code>abc HGFED xyz</code>" ("HGF" is not adjacent to "xyz")

Parameters

pBiDi	is a paragraphUBiDi object.
prologue	is a pointer to the text which precedes the text that will be specified in a coming call toubidi_setPara(). If there is no prologue to consider, thenproLength must be zero and this pointer can be NULL.
proLength	is the length of the prologue; ifproLength==-1 then the prologue must be zero-terminated. Otherwise proLength must be >= 0. IfproLength==0, it means that there is no prologue to consider.
epilogue	is a pointer to the text which follows the text that will be specified in a coming call toubidi_setPara(). If there is no epilogue to consider, thenepiLength must be zero and this pointer can be NULL.
epiLength	is the length of the epilogue; ifepiLength==-1 then the epilogue must be zero-terminated. Otherwise epiLength must be >= 0. IfepiLength==0, it means that there is no epilogue to consider.
pErrorCode	must be a valid pointer to an error code value.

See also

ubidi_setPara

Stable:

ICU 4.8

Modify the operation of the Bidi algorithm such that it approximates an "inverse Bidi" algorithm.

This function must be called beforeubidi_setPara().

The normal operation of the Bidi algorithm as described in the Unicode Technical Report is to take text stored in logical (keyboard, typing) order and to determine the reordering of it for visual rendering. Some legacy systems store text in visual order, and for operations with standard, Unicode-based algorithms, the text needs to be transformed to logical order. This is effectively the inverse algorithm of the described Bidi algorithm. Note that there is no standard algorithm for this "inverse Bidi" and that the current implementation provides only an approximation of "inverse Bidi".

WithisInverse set totrue, 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 usingubidi_getVisualRun(). Since the actual input for "inverse Bidi" is visually ordered text andubidi_getVisualRun() gets the reordered runs, these are actually the runs of the logically ordered output.

Calling this function with argumentisInverse set totrue is equivalent to callingubidi_setReorderingMode with argumentreorderingMode set toUBIDI_REORDER_INVERSE_NUMBERS_AS_L.
Calling this function with argumentisInverse set tofalse is equivalent to callingubidi_setReorderingMode with argumentreorderingMode set toUBIDI_REORDER_DEFAULT.

Parameters

pBiDi	is aUBiDi object.
isInverse	specifies "forward" or "inverse" Bidi operation.

See also

ubidi_setPara

ubidi_writeReordered

ubidi_setReorderingMode

Stable:

ICU 2.0

ubidi_setLine() sets aUBiDi 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 aUBiDi object representing this information for a piece of text containing one or more paragraphs, and by specifying a range of indexes in this text.

In the new line object, the indexes will range from 0 tolimit-start-1.

This is used after callingubidi_setPara() for a piece of text, and after line-breaking on that text. It is not necessary if each paragraph is treated as a single line.

After line-breaking, rules (L1) and (L2) for the treatment of trailing WS and for reordering are performed on aUBiDi object that represents a line.

Important:pLineBiDi shares data withpParaBiDi. You must destroy or reusepLineBiDi beforepParaBiDi. In other words, you must destroy or reuse theUBiDi object for a line before the object for its parent paragraph.

The text pointer that was stored inpParaBiDi is also copied, andstart is added to it so that it points to the beginning of the line for this object.

Parameters

pParaBiDi	is the parent paragraph object. It must have been set by a successful call to ubidi_setPara.
start	is the line's first index into the text.
limit	is just behind the line's last index into the text (its last index +1). It must be0<=start<limit<=containing paragraph limit. If the specified line crosses a paragraph boundary, the function will terminate with error code U_ILLEGAL_ARGUMENT_ERROR.
pLineBiDi	is the object that will now represent a line of the text.
pErrorCode	must be a valid pointer to an error code value.

See also

ubidi_setPara

ubidi_getProcessedLength

Stable:

ICU 2.0

Perform the Unicode Bidi algorithm.

It is defined in theUnicode Standard Annex #9, version 13, also described in The Unicode Standard, Version 4.0 .

This function takes a piece of plain text containing one or more paragraphs, with or without externally specified embedding levels fromstyled text and computes the left-right-directionality of each character.

If the entire text is all of the same directionality, then the function may not perform all the steps described by the algorithm, i.e., some levels may not be the same as if all steps were performed. This is not relevant for unidirectional text.
For example, in pure LTR text with numbers the numbers would get a resolved level of 2 higher than the surrounding text according to the algorithm. This implementation may set all resolved levels to the same value in such a case.

The text can be composed of multiple paragraphs. Occurrence of a block separator in the text terminates a paragraph, and whatever comes next starts a new paragraph. The exception to this rule is when a Carriage Return (CR) is followed by a Line Feed (LF). Both CR and LF are block separators, but in that case, the pair of characters is considered as terminating the preceding paragraph, and a new paragraph will be started by a character coming after the LF.

Parameters

pBiDi	AUBiDi object allocated withubidi_open() which will be set to contain the reordering information, especially the resolved levels for all the characters intext.
text	is a pointer to the text that the Bidi algorithm will be performed on. This pointer is stored in the UBiDi object and can be retrieved withubidi_getText(). Note: the text must be (at least)length long.
length	is the length of the text; iflength==-1 then the text must be zero-terminated.
paraLevel	specifies the default level for the text; it is typically 0 (LTR) or 1 (RTL). If the function shall determine the paragraph level from the text, thenparaLevel can be set to eitherUBIDI_DEFAULT_LTR orUBIDI_DEFAULT_RTL; if the text contains multiple paragraphs, the paragraph level shall be determined separately for each paragraph; if a paragraph does not include any strongly typed character, then the desired default is used (0 for LTR or 1 for RTL). Any other value between 0 andUBIDI_MAX_EXPLICIT_LEVEL is also valid, with odd levels indicating RTL.
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 theUBIDI_LEVEL_OVERRIDE bit set. Aside from that bit, it must beparaLevel<=embeddingLevels[]<=UBIDI_MAX_EXPLICIT_LEVEL, except that level 0 is always allowed. Level 0 for a paragraph separator prevents reordering of paragraphs; this only works reliably ifUBIDI_LEVEL_OVERRIDE is also set for paragraph separators. Level 0 for other characters is treated as a wildcard and is lifted up to the resolved level of the surrounding paragraph. Caution:A copy of this pointer, not of the levels, will be stored in theUBiDi object; theembeddingLevels array must not be deallocated before theUBiDi structure is destroyed or reused, and theembeddingLevels should not be modified to avoid unexpected results on subsequent Bidi operations. However, theubidi_setPara() andubidi_setLine() functions may modify some or all of the levels. After theUBiDi object is reused or destroyed, the caller must take care of the deallocation of theembeddingLevels array. Note: theembeddingLevels array must be at leastlength long. This pointer can beNULL if this value is not necessary.
pErrorCode	must be a valid pointer to an error code value.

Stable:

ICU 2.0

Modify the operation of the Bidi algorithm such that it implements some variant to the basic Bidi algorithm or approximates an "inverse Bidi" algorithm, depending on different values of the "reordering mode".

This function must be called beforeubidi_setPara(), and stays in effect until called again with a different argument.

The normal operation of the Bidi algorithm as described in the Unicode Standard Annex #9 is to take text stored in logical (keyboard, typing) order and to determine how to reorder it for visual rendering.

With the reordering mode set to a value other thanUBIDI_REORDER_DEFAULT, this function changes the behavior of some of the subsequent functions in a way such that they implement an inverse Bidi algorithm or some other algorithm variants.

Some legacy systems store text in visual order, and for operations with standard, Unicode-based algorithms, the text needs to be transformed into logical order. This is effectively the inverse algorithm of the described Bidi algorithm. Note that there is no standard algorithm for this "inverse Bidi", so a number of variants are implemented here.

In other cases, it may be desirable to emulate some variant of the Logical to Visual algorithm (e.g. one used in MS Windows), or perform a Logical to Logical transformation.

• When the reordering mode is set toUBIDI_REORDER_DEFAULT, the standard Bidi Logical to Visual algorithm is applied.

• When the reordering mode is set toUBIDI_REORDER_NUMBERS_SPECIAL, the algorithm used to perform Bidi transformations when callingubidi_setPara should approximate the algorithm used in Microsoft Windows XP rather than strictly conform to the Unicode Bidi algorithm.
  The differences between the basic algorithm and the algorithm addressed by this option are as follows:

  • Within text at an even embedding level, the sequence "123AB" (where AB represent R or AL letters) is transformed to "123BA" by the Unicode algorithm and to "BA123" by the Windows algorithm.
  • Arabic-Indic numbers (AN) are handled by the Windows algorithm just like regular numbers (EN).

• When the reordering mode is set toUBIDI_REORDER_GROUP_NUMBERS_WITH_R, numbers located between LTR text and RTL text are associated with the RTL text. For instance, an LTR paragraph with content "abc 123 DEF" (where upper case letters represent RTL characters) will be transformed to "abc FED 123" (and not "abc 123 FED"), "DEF 123 abc" will be transformed to "123 FED abc" and "123 FED abc" will be transformed to "DEF 123 abc". This makes the algorithm reversible and makes it useful when round trip (from visual to logical and back to visual) must be achieved without adding LRM characters. However, this is a variation from the standard Unicode Bidi algorithm.
  The source text should not contain Bidi control characters other than LRM or RLM.

• When the reordering mode is set toUBIDI_REORDER_RUNS_ONLY, a "Logical to Logical" transformation must be performed:

  • If the default text level of the source text (argumentparaLevel inubidi_setPara) is even, the source text will be handled as LTR logical text and will be transformed to the RTL logical text which has the same LTR visual display.
  • If the default level of the source text is odd, the source text will be handled as RTL logical text and will be transformed to the LTR logical text which has the same LTR visual display.

  This mode may be needed when logical text which is basically Arabic or Hebrew, with possible included numbers or phrases in English, has to be displayed as if it had an even embedding level (this can happen if the displaying application treats all text as if it was basically LTR).
  This mode may also be needed in the reverse case, when logical text which is basically English, with possible included phrases in Arabic or Hebrew, has to be displayed as if it had an odd embedding level.
  Both cases could be handled by adding LRE or RLE at the head of the text, if the display subsystem supports these formatting controls. If it does not, the problem may be handled by transforming the source text in this mode before displaying it, so that it will be displayed properly.
  The source text should not contain Bidi control characters other than LRM or RLM.

• When the reordering mode is set toUBIDI_REORDER_INVERSE_NUMBERS_AS_L, an "inverse Bidi" algorithm is applied. Runs of text with numeric characters will be treated like LTR letters and may need to be surrounded with LRM characters when they are written in reordered sequence (the optionUBIDI_INSERT_LRM_FOR_NUMERIC can be used with functionubidi_writeReordered to this end. This mode is equivalent to callingubidi_setInverse() with argumentisInverse set totrue.

• When the reordering mode is set toUBIDI_REORDER_INVERSE_LIKE_DIRECT, the "direct" Logical to Visual Bidi algorithm is used as an approximation of an "inverse Bidi" algorithm. This mode is similar to modeUBIDI_REORDER_INVERSE_NUMBERS_AS_L but is closer to the regular Bidi algorithm.
  For example, an LTR paragraph with the content "FED 123 456 CBA" (where upper case represents RTL characters) will be transformed to "ABC 456 123 DEF", as opposed to "DEF 123 456 ABC" with modeUBIDI_REORDER_INVERSE_NUMBERS_AS_L.
  When used in conjunction with optionUBIDI_OPTION_INSERT_MARKS, this mode generally adds Bidi marks to the output significantly more sparingly than modeUBIDI_REORDER_INVERSE_NUMBERS_AS_L with optionUBIDI_INSERT_LRM_FOR_NUMERIC in calls toubidi_writeReordered.

• When the reordering mode is set toUBIDI_REORDER_INVERSE_FOR_NUMBERS_SPECIAL, the Logical to Visual Bidi algorithm used in Windows XP is used as an approximation of an "inverse Bidi" algorithm.
  For example, an LTR paragraph with the content "abc FED123" (where upper case represents RTL characters) will be transformed to "abc 123DEF."

In all the reordering modes specifying an "inverse Bidi" algorithm (i.e. those with a name starting withUBIDI_REORDER_INVERSE), output runs should be retrieved usingubidi_getVisualRun(), and the output text withubidi_writeReordered(). The caller should keep in mind that in "inverse Bidi" modes the input is actually visually ordered text and reordered output returned byubidi_getVisualRun() orubidi_writeReordered() are actually runs or character string of logically ordered output.
For all the "inverse Bidi" modes, the source text should not contain Bidi control characters other than LRM or RLM.

Note that optionUBIDI_OUTPUT_REVERSE ofubidi_writeReordered has no useful meaning and should not be used in conjunction with any value of the reordering mode specifying "inverse Bidi" or with valueUBIDI_REORDER_RUNS_ONLY.

Parameters

pBiDi	is aUBiDi object.
reorderingMode	specifies the required variant of the Bidi algorithm.

See also

UBiDiReorderingMode

ubidi_setInverse

ubidi_setPara

ubidi_writeReordered

Stable:

ICU 3.6

Specify which of the reordering options should be applied during Bidi transformations.

Parameters

pBiDi	is aUBiDi object.
reorderingOptions	is a combination of zero or more of the following options:UBIDI_OPTION_DEFAULT,UBIDI_OPTION_INSERT_MARKS,UBIDI_OPTION_REMOVE_CONTROLS,UBIDI_OPTION_STREAMING.

See also

ubidi_getReorderingOptions

Stable:

ICU 3.6

Take aUBiDi object containing the reordering information for a piece of text (one or more paragraphs) set byubidi_setPara() or for a line of text set byubidi_setLine() and write a reordered string to the destination buffer.

This function preserves the integrity of characters with multiple code units and (optionally) combining characters. 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 thedestSize andoptions parameters and of the option bit flags.

Parameters

pBiDi	A pointer to aUBiDi object that is set byubidi_setPara() orubidi_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 theubidi_setPara() call.
dest	A pointer to where the reordered text is to be copied. The source text anddest[destSize] must not overlap.
destSize	The size of thedest buffer, in number of UChars. If theUBIDI_INSERT_LRM_FOR_NUMERIC option is set, then the destination length could be as large asubidi_getLength(pBiDi)+2*ubidi_countRuns(pBiDi). If theUBIDI_REMOVE_BIDI_CONTROLS option is set, then the destination length may be less thanubidi_getLength(pBiDi). If none of these options is set, then the destination length will be exactlyubidi_getProcessedLength(pBiDi).
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:UBIDI_DO_MIRRORING,UBIDI_INSERT_LRM_FOR_NUMERIC,UBIDI_KEEP_BASE_COMBINING,UBIDI_OUTPUT_REVERSE,UBIDI_REMOVE_BIDI_CONTROLS
pErrorCode	must be a valid pointer to an error code value.

Returns

The length of the output string.

See also

ubidi_getProcessedLength

Stable:

ICU 2.0

Reverse a Right-To-Left run of Unicode text.

This function preserves the integrity of characters with multiple code units and (optionally) combining characters. 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 ofubidi_writeReordered(). For detailed descriptions of the parameters, see there. Since no Bidi controls are inserted here, the output string length will never exceedsrcLength.

See also

ubidi_writeReordered

Parameters

src	A pointer to the RTL run text.
srcLength	The length of the RTL run.
dest	A pointer to where the reordered text is to be copied.src[srcLength] anddest[destSize] must not overlap.
destSize	The size of thedest buffer, in number of UChars. If theUBIDI_REMOVE_BIDI_CONTROLS option is set, then the destination length may be less thansrcLength. If this option is not set, then the destination length will be exactlysrcLength.
options	A bit set of options for the reordering that control how the reordered text is written. See theoptions parameter inubidi_writeReordered().
pErrorCode	must be a valid pointer to an error code value.

Returns

The length of the output string.

Stable:

ICU 2.0