/* ****************************************************************************** * * Copyright (C) 2000-2004, International Business Machines * Corporation and others. All Rights Reserved. * ****************************************************************************** * file name: ushape.h * encoding: US-ASCII * tab size: 8 (not used) * indentation:4 * * created on: 2000jun29 * created by: Markus W. Scherer */ #ifndef __USHAPE_H__ #define __USHAPE_H__ #include "unicode/utypes.h" /** * \file * \brief C API: Arabic shaping * */ /** * Shape Arabic text on a character basis. * * <p>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.</p> * * <p>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.</p> * * <p>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.</p> * * <p>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).</p> * * <p>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.</p> * * <p>For details about the available operations, see the description of the * <code>U_SHAPE_...</code> options.</p> * * @param source The input text. * * @param sourceLength The number of UChars in <code>source</code>. * * @param dest The destination buffer that will receive the results of the * requested operations. It may be <code>NULL</code> only if * <code>destSize</code> is 0. The source and destination must not * overlap. * * @param destSize The size (capacity) of the destination buffer in UChars. * If <code>destSize</code> 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 <code>U_BUFFER_OVERFLOW_ERROR</code> 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 * (<code>u_charDirection()</code> result <code>U_RIGHT_TO_LEFT_ARABIC</code> [AL]).<br> * The direction of "preceding" depends on the direction indicator option. * For the first characters, the preceding strongly directional character * (initial state) is assumed to be not an Arabic letter * (it is <code>U_LEFT_TO_RIGHT</code> [L] or <code>U_RIGHT_TO_LEFT</code> [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 * (<code>u_charDirection()</code> result <code>U_RIGHT_TO_LEFT_ARABIC</code> [AL]).<br> * The direction of "preceding" depends on the direction indicator option. * For the first characters, the preceding strongly directional character * (initial state) is assumed to be an Arabic letter. * @stable ICU 2.0 */ #define U_SHAPE_DIGITS_ALEN2AN_INIT_AL 0x80 /** Not a valid option value. May be replaced by a new option. @stable ICU 2.0 */ #define U_SHAPE_DIGITS_RESERVED 0xa0 /** Bit mask for digit shaping options. @stable ICU 2.0 */ #define U_SHAPE_DIGITS_MASK 0xe0 /** Digit type option: Use Arabic-Indic digits (U+0660...U+0669). @stable ICU 2.0 */ #define U_SHAPE_DIGIT_TYPE_AN 0 /** Digit type option: Use Eastern (Extended) Arabic-Indic digits (U+06f0...U+06f9). @stable ICU 2.0 */ #define U_SHAPE_DIGIT_TYPE_AN_EXTENDED 0x100 /** Not a valid option value. May be replaced by a new option. @stable ICU 2.0 */ #define U_SHAPE_DIGIT_TYPE_RESERVED 0x200 /** Bit mask for digit type options. @stable ICU 2.0 */ #define U_SHAPE_DIGIT_TYPE_MASK 0x3f00 #endif