2
******************************************************************************
4
* Copyright (C) 2000-2001, International Business Machines
5
* Corporation and others. All Rights Reserved.
7
******************************************************************************
10
* tab size: 8 (not used)
13
* created on: 2000jun29
14
* created by: Markus W. Scherer
20
#include "unicode/utypes.h"
24
* \brief C API: Arabic shaping
29
* Shape Arabic text on a character basis.
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>
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>
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>
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>
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
69
* <p>For details about the available operations, see the description of the
70
* <code>U_SHAPE_...</code> options.</p>
72
* @param source The input text.
74
* @param sourceLength The number of UChars in <code>source</code>.
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
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").
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
90
* @param pErrorCode must be a valid pointer to an error code value,
91
* which must not indicate a failure before the function call.
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.
99
U_CAPI int32_t U_EXPORT2
100
u_shapeArabic(const UChar *source, int32_t sourceLength,
101
UChar *dest, int32_t destSize,
103
UErrorCode *pErrorCode);
106
* Memory option: allow the result to have a different length than the source.
109
#define U_SHAPE_LENGTH_GROW_SHRINK 0
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.
116
#define U_SHAPE_LENGTH_FIXED_SPACES_NEAR 1
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.
123
#define U_SHAPE_LENGTH_FIXED_SPACES_AT_END 2
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.
130
#define U_SHAPE_LENGTH_FIXED_SPACES_AT_BEGINNING 3
132
/** Bit mask for memory options. @stable */
133
#define U_SHAPE_LENGTH_MASK 3
136
/** Direction indicator: the source is in logical (keyboard) order. @stable */
137
#define U_SHAPE_TEXT_DIRECTION_LOGICAL 0
140
* Direction indicator:
141
* the source is in visual LTR order,
142
* the leftmost displayed character stored first.
145
#define U_SHAPE_TEXT_DIRECTION_VISUAL_LTR 4
147
/** Bit mask for direction indicators. @stable */
148
#define U_SHAPE_TEXT_DIRECTION_MASK 4
151
/** Letter shaping option: do not perform letter shaping. @stable */
152
#define U_SHAPE_LETTERS_NOOP 0
154
/** Letter shaping option: replace abstract letter characters by "shaped" ones. @stable */
155
#define U_SHAPE_LETTERS_SHAPE 8
157
/** Letter shaping option: replace "shaped" letter characters by abstract ones. @stable */
158
#define U_SHAPE_LETTERS_UNSHAPE 0x10
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).
167
#define U_SHAPE_LETTERS_SHAPE_TASHKEEL_ISOLATED 0x18
169
/** Bit mask for letter shaping options. @stable */
170
#define U_SHAPE_LETTERS_MASK 0x18
173
/** Digit shaping option: do not perform digit shaping. @stable */
174
#define U_SHAPE_DIGITS_NOOP 0
177
* Digit shaping option:
178
* Replace European digits (U+0030...) by Arabic-Indic digits.
181
#define U_SHAPE_DIGITS_EN2AN 0x20
184
* Digit shaping option:
185
* Replace Arabic-Indic digits by European digits (U+0030...).
188
#define U_SHAPE_DIGITS_AN2EN 0x40
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]).
201
#define U_SHAPE_DIGITS_ALEN2AN_INIT_LR 0x60
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.
213
#define U_SHAPE_DIGITS_ALEN2AN_INIT_AL 0x80
215
/** Not a valid option value. May be replaced by a new option. */
216
#define U_SHAPE_DIGITS_RESERVED 0xa0
218
/** Bit mask for digit shaping options. @stable */
219
#define U_SHAPE_DIGITS_MASK 0xe0
222
/** Digit type option: Use Arabic-Indic digits (U+0660...U+0669). @stable */
223
#define U_SHAPE_DIGIT_TYPE_AN 0
225
/** Digit type option: Use Eastern (Extended) Arabic-Indic digits (U+06f0...U+06f9). @stable */
226
#define U_SHAPE_DIGIT_TYPE_AN_EXTENDED 0x100
228
/** Not a valid option value. May be replaced by a new option. */
229
#define U_SHAPE_DIGIT_TYPE_RESERVED 0x200
231
/** Bit mask for digit type options. @stable */
232
#define U_SHAPE_DIGIT_TYPE_MASK 0x3f00