This function performs basic operations for "shaping" Arabic text. It is most + * useful for use with legacy data formats and legacy display technology + * (simple terminals). All operations are performed on Unicode characters.
+ * + *Text-based shaping means that some character code points in the text are + * replaced by others depending on the context. It transforms one kind of text + * into another. In comparison, modern displays for Arabic text select + * appropriate, context-dependent font glyphs for each text element, which means + * that they transform text into a glyph vector.
+ * + *Text transformations are necessary when modern display technology is not + * available or when text needs to be transformed to or from legacy formats that + * use "shaped" characters. Since the Arabic script is cursive, connecting + * adjacent letters to each other, computers select images for each letter based + * on the surrounding letters. This usually results in four images per Arabic + * letter: initial, middle, final, and isolated forms. In Unicode, on the other + * hand, letters are normally stored abstract, and a display system is expected + * to select the necessary glyphs. (This makes searching and other text + * processing easier because the same letter has only one code.) It is possible + * to mimic this with text transformations because there are characters in + * Unicode that are rendered as letters with a specific shape + * (or cursive connectivity). They were included for interoperability with + * legacy systems and codepages, and for unsophisticated display systems.
+ * + *A second kind of text transformations is supported for Arabic digits: + * For compatibility with legacy codepages that only include European digits, + * it is possible to replace one set of digits by another, changing the + * character code points. These operations can be performed for either + * Arabic-Indic Digits (U+0660...U+0669) or Eastern (Extended) Arabic-Indic + * digits (U+06f0...U+06f9).
+ * + *Some replacements may result in more or fewer characters (code points). + * By default, this means that the destination buffer may receive text with a + * length different from the source length. Some legacy systems rely on the + * length of the text to be constant. They expect extra spaces to be added + * or consumed either next to the affected character or at the end of the + * text.
+ * + *For details about the available operations, see the description of the
+ * U_SHAPE_... options.
source.
+ *
+ * @param dest The destination buffer that will receive the results of the
+ * requested operations. It may be NULL only if
+ * destSize is 0. The source and destination must not
+ * overlap.
+ *
+ * @param destSize The size (capacity) of the destination buffer in UChars.
+ * If destSize is 0, then no output is produced,
+ * but the necessary buffer size is returned ("preflighting").
+ *
+ * @param options This is a 32-bit set of flags that specify the operations
+ * that are performed on the input text. If no error occurs,
+ * then the result will always be written to the destination
+ * buffer.
+ *
+ * @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 UChars written to the destination buffer.
+ * If an error occured, then no output was written, or it may be
+ * incomplete. If U_BUFFER_OVERFLOW_ERROR is set, then
+ * the return value indicates the necessary destination buffer size.
+ * @stable ICU 2.0
+ */
+U_STABLE int32_t U_EXPORT2
+u_shapeArabic(const UChar *source, int32_t sourceLength,
+ UChar *dest, int32_t destSize,
+ uint32_t options,
+ UErrorCode *pErrorCode);
+
+/**
+ * Memory option: allow the result to have a different length than the source.
+ * @stable ICU 2.0
+ */
+#define U_SHAPE_LENGTH_GROW_SHRINK 0
+
+/**
+ * Memory option: the result must have the same length as the source.
+ * If more room is necessary, then try to consume spaces next to modified characters.
+ * @stable ICU 2.0
+ */
+#define U_SHAPE_LENGTH_FIXED_SPACES_NEAR 1
+
+/**
+ * Memory option: the result must have the same length as the source.
+ * If more room is necessary, then try to consume spaces at the end of the text.
+ * @stable ICU 2.0
+ */
+#define U_SHAPE_LENGTH_FIXED_SPACES_AT_END 2
+
+/**
+ * Memory option: the result must have the same length as the source.
+ * If more room is necessary, then try to consume spaces at the beginning of the text.
+ * @stable ICU 2.0
+ */
+#define U_SHAPE_LENGTH_FIXED_SPACES_AT_BEGINNING 3
+
+/** Bit mask for memory options. @stable ICU 2.0 */
+#define U_SHAPE_LENGTH_MASK 3
+
+
+/** Direction indicator: the source is in logical (keyboard) order. @stable ICU 2.0 */
+#define U_SHAPE_TEXT_DIRECTION_LOGICAL 0
+
+/**
+ * Direction indicator:
+ * the source is in visual LTR order,
+ * the leftmost displayed character stored first.
+ * @stable ICU 2.0
+ */
+#define U_SHAPE_TEXT_DIRECTION_VISUAL_LTR 4
+
+/** Bit mask for direction indicators. @stable ICU 2.0 */
+#define U_SHAPE_TEXT_DIRECTION_MASK 4
+
+
+/** Letter shaping option: do not perform letter shaping. @stable ICU 2.0 */
+#define U_SHAPE_LETTERS_NOOP 0
+
+/** Letter shaping option: replace abstract letter characters by "shaped" ones. @stable ICU 2.0 */
+#define U_SHAPE_LETTERS_SHAPE 8
+
+/** Letter shaping option: replace "shaped" letter characters by abstract ones. @stable ICU 2.0 */
+#define U_SHAPE_LETTERS_UNSHAPE 0x10
+
+/**
+ * Letter shaping option: replace abstract letter characters by "shaped" ones.
+ * The only difference with U_SHAPE_LETTERS_SHAPE is that Tashkeel letters
+ * are always "shaped" into the isolated form instead of the medial form
+ * (selecting code points from the Arabic Presentation Forms-B block).
+ * @stable ICU 2.0
+ */
+#define U_SHAPE_LETTERS_SHAPE_TASHKEEL_ISOLATED 0x18
+
+/** Bit mask for letter shaping options. @stable ICU 2.0 */
+#define U_SHAPE_LETTERS_MASK 0x18
+
+
+/** Digit shaping option: do not perform digit shaping. @stable ICU 2.0 */
+#define U_SHAPE_DIGITS_NOOP 0
+
+/**
+ * Digit shaping option:
+ * Replace European digits (U+0030...) by Arabic-Indic digits.
+ * @stable ICU 2.0
+ */
+#define U_SHAPE_DIGITS_EN2AN 0x20
+
+/**
+ * Digit shaping option:
+ * Replace Arabic-Indic digits by European digits (U+0030...).
+ * @stable ICU 2.0
+ */
+#define U_SHAPE_DIGITS_AN2EN 0x40
+
+/**
+ * Digit shaping option:
+ * Replace European digits (U+0030...) by Arabic-Indic digits if the most recent
+ * strongly directional character is an Arabic letter
+ * (u_charDirection() result U_RIGHT_TO_LEFT_ARABIC [AL]).U_LEFT_TO_RIGHT [L] or U_RIGHT_TO_LEFT [R]).
+ * @stable ICU 2.0
+ */
+#define U_SHAPE_DIGITS_ALEN2AN_INIT_LR 0x60
+
+/**
+ * Digit shaping option:
+ * Replace European digits (U+0030...) by Arabic-Indic digits if the most recent
+ * strongly directional character is an Arabic letter
+ * (u_charDirection() result U_RIGHT_TO_LEFT_ARABIC [AL]).