1 /* 2 ****************************************************************************** 3 * 4 * Copyright (C) 2000-2004, International Business Machines 5 * Corporation and others. All Rights Reserved. 6 * 7 ****************************************************************************** 8 * file name: ushape.h 9 * encoding: US-ASCII 10 * tab size: 8 (not used) 11 * indentation:4 12 * 13 * created on: 2000jun29 14 * created by: Markus W. Scherer 15 */ 16 17 #ifndef __USHAPE_H__ 18 #define __USHAPE_H__ 19 20 #include "unicode/utypes.h" 21 22 /** 23 * \file 24 * \brief C API: Arabic shaping 25 * 26 */ 27 28 /** 29 * Shape Arabic text on a character basis. 30 * 31 * <p>This function performs basic operations for "shaping" Arabic text. It is most 32 * useful for use with legacy data formats and legacy display technology 33 * (simple terminals). All operations are performed on Unicode characters.</p> 34 * 35 * <p>Text-based shaping means that some character code points in the text are 36 * replaced by others depending on the context. It transforms one kind of text 37 * into another. In comparison, modern displays for Arabic text select 38 * appropriate, context-dependent font glyphs for each text element, which means 39 * that they transform text into a glyph vector.</p> 40 * 41 * <p>Text transformations are necessary when modern display technology is not 42 * available or when text needs to be transformed to or from legacy formats that 43 * use "shaped" characters. Since the Arabic script is cursive, connecting 44 * adjacent letters to each other, computers select images for each letter based 45 * on the surrounding letters. This usually results in four images per Arabic 46 * letter: initial, middle, final, and isolated forms. In Unicode, on the other 47 * hand, letters are normally stored abstract, and a display system is expected 48 * to select the necessary glyphs. (This makes searching and other text 49 * processing easier because the same letter has only one code.) It is possible 50 * to mimic this with text transformations because there are characters in 51 * Unicode that are rendered as letters with a specific shape 52 * (or cursive connectivity). They were included for interoperability with 53 * legacy systems and codepages, and for unsophisticated display systems.</p> 54 * 55 * <p>A second kind of text transformations is supported for Arabic digits: 56 * For compatibility with legacy codepages that only include European digits, 57 * it is possible to replace one set of digits by another, changing the 58 * character code points. These operations can be performed for either 59 * Arabic-Indic Digits (U+0660...U+0669) or Eastern (Extended) Arabic-Indic 60 * digits (U+06f0...U+06f9).</p> 61 * 62 * <p>Some replacements may result in more or fewer characters (code points). 63 * By default, this means that the destination buffer may receive text with a 64 * length different from the source length. Some legacy systems rely on the 65 * length of the text to be constant. They expect extra spaces to be added 66 * or consumed either next to the affected character or at the end of the 67 * text.</p> 68 * 69 * <p>For details about the available operations, see the description of the 70 * <code>U_SHAPE_...</code> options.</p> 71 * 72 * @param source The input text. 73 * 74 * @param sourceLength The number of UChars in <code>source</code>. 75 * 76 * @param dest The destination buffer that will receive the results of the 77 * requested operations. It may be <code>NULL</code> only if 78 * <code>destSize</code> is 0. The source and destination must not 79 * overlap. 80 * 81 * @param destSize The size (capacity) of the destination buffer in UChars. 82 * If <code>destSize</code> is 0, then no output is produced, 83 * but the necessary buffer size is returned ("preflighting"). 84 * 85 * @param options This is a 32-bit set of flags that specify the operations 86 * that are performed on the input text. If no error occurs, 87 * then the result will always be written to the destination 88 * buffer. 89 * 90 * @param pErrorCode must be a valid pointer to an error code value, 91 * which must not indicate a failure before the function call. 92 * 93 * @return The number of UChars written to the destination buffer. 94 * If an error occured, then no output was written, or it may be 95 * incomplete. If <code>U_BUFFER_OVERFLOW_ERROR</code> is set, then 96 * the return value indicates the necessary destination buffer size. 97 * @stable ICU 2.0 98 */ 99 U_STABLE int32_t U_EXPORT2 100 u_shapeArabic(const UChar *source, int32_t sourceLength, 101 UChar *dest, int32_t destSize, 102 uint32_t options, 103 UErrorCode *pErrorCode); 104 105 /** 106 * Memory option: allow the result to have a different length than the source. 107 * @stable ICU 2.0 108 */ 109 #define U_SHAPE_LENGTH_GROW_SHRINK 0 110 111 /** 112 * Memory option: the result must have the same length as the source. 113 * If more room is necessary, then try to consume spaces next to modified characters. 114 * @stable ICU 2.0 115 */ 116 #define U_SHAPE_LENGTH_FIXED_SPACES_NEAR 1 117 118 /** 119 * Memory option: the result must have the same length as the source. 120 * If more room is necessary, then try to consume spaces at the end of the text. 121 * @stable ICU 2.0 122 */ 123 #define U_SHAPE_LENGTH_FIXED_SPACES_AT_END 2 124 125 /** 126 * Memory option: the result must have the same length as the source. 127 * If more room is necessary, then try to consume spaces at the beginning of the text. 128 * @stable ICU 2.0 129 */ 130 #define U_SHAPE_LENGTH_FIXED_SPACES_AT_BEGINNING 3 131 132 /** Bit mask for memory options. @stable ICU 2.0 */ 133 #define U_SHAPE_LENGTH_MASK 3 134 135 136 /** Direction indicator: the source is in logical (keyboard) order. @stable ICU 2.0 */ 137 #define U_SHAPE_TEXT_DIRECTION_LOGICAL 0 138 139 /** 140 * Direction indicator: 141 * the source is in visual LTR order, 142 * the leftmost displayed character stored first. 143 * @stable ICU 2.0 144 */ 145 #define U_SHAPE_TEXT_DIRECTION_VISUAL_LTR 4 146 147 /** Bit mask for direction indicators. @stable ICU 2.0 */ 148 #define U_SHAPE_TEXT_DIRECTION_MASK 4 149 150 151 /** Letter shaping option: do not perform letter shaping. @stable ICU 2.0 */ 152 #define U_SHAPE_LETTERS_NOOP 0 153 154 /** Letter shaping option: replace abstract letter characters by "shaped" ones. @stable ICU 2.0 */ 155 #define U_SHAPE_LETTERS_SHAPE 8 156 157 /** Letter shaping option: replace "shaped" letter characters by abstract ones. @stable ICU 2.0 */ 158 #define U_SHAPE_LETTERS_UNSHAPE 0x10 159 160 /** 161 * Letter shaping option: replace abstract letter characters by "shaped" ones. 162 * The only difference with U_SHAPE_LETTERS_SHAPE is that Tashkeel letters 163 * are always "shaped" into the isolated form instead of the medial form 164 * (selecting code points from the Arabic Presentation Forms-B block). 165 * @stable ICU 2.0 166 */ 167 #define U_SHAPE_LETTERS_SHAPE_TASHKEEL_ISOLATED 0x18 168 169 /** Bit mask for letter shaping options. @stable ICU 2.0 */ 170 #define U_SHAPE_LETTERS_MASK 0x18 171 172 173 /** Digit shaping option: do not perform digit shaping. @stable ICU 2.0 */ 174 #define U_SHAPE_DIGITS_NOOP 0 175 176 /** 177 * Digit shaping option: 178 * Replace European digits (U+0030...) by Arabic-Indic digits. 179 * @stable ICU 2.0 180 */ 181 #define U_SHAPE_DIGITS_EN2AN 0x20 182 183 /** 184 * Digit shaping option: 185 * Replace Arabic-Indic digits by European digits (U+0030...). 186 * @stable ICU 2.0 187 */ 188 #define U_SHAPE_DIGITS_AN2EN 0x40 189 190 /** 191 * Digit shaping option: 192 * Replace European digits (U+0030...) by Arabic-Indic digits if the most recent 193 * strongly directional character is an Arabic letter 194 * (<code>u_charDirection()</code> result <code>U_RIGHT_TO_LEFT_ARABIC</code> [AL]).<br> 195 * The direction of "preceding" depends on the direction indicator option. 196 * For the first characters, the preceding strongly directional character 197 * (initial state) is assumed to be not an Arabic letter 198 * (it is <code>U_LEFT_TO_RIGHT</code> [L] or <code>U_RIGHT_TO_LEFT</code> [R]). 199 * @stable ICU 2.0 200 */ 201 #define U_SHAPE_DIGITS_ALEN2AN_INIT_LR 0x60 202 203 /** 204 * Digit shaping option: 205 * Replace European digits (U+0030...) by Arabic-Indic digits if the most recent 206 * strongly directional character is an Arabic letter 207 * (<code>u_charDirection()</code> result <code>U_RIGHT_TO_LEFT_ARABIC</code> [AL]).<br> 208 * The direction of "preceding" depends on the direction indicator option. 209 * For the first characters, the preceding strongly directional character 210 * (initial state) is assumed to be an Arabic letter. 211 * @stable ICU 2.0 212 */ 213 #define U_SHAPE_DIGITS_ALEN2AN_INIT_AL 0x80 214 215 /** Not a valid option value. May be replaced by a new option. @stable ICU 2.0 */ 216 #define U_SHAPE_DIGITS_RESERVED 0xa0 217 218 /** Bit mask for digit shaping options. @stable ICU 2.0 */ 219 #define U_SHAPE_DIGITS_MASK 0xe0 220 221 222 /** Digit type option: Use Arabic-Indic digits (U+0660...U+0669). @stable ICU 2.0 */ 223 #define U_SHAPE_DIGIT_TYPE_AN 0 224 225 /** Digit type option: Use Eastern (Extended) Arabic-Indic digits (U+06f0...U+06f9). @stable ICU 2.0 */ 226 #define U_SHAPE_DIGIT_TYPE_AN_EXTENDED 0x100 227 228 /** Not a valid option value. May be replaced by a new option. @stable ICU 2.0 */ 229 #define U_SHAPE_DIGIT_TYPE_RESERVED 0x200 230 231 /** Bit mask for digit type options. @stable ICU 2.0 */ 232 #define U_SHAPE_DIGIT_TYPE_MASK 0x3f00 233 234 #endif 235