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b7b65b15 | 1 | /* Low-level bidirectional buffer-scanning functions for GNU Emacs. |
c143c213 | 2 | Copyright (C) 2000, 2001, 2004, 2005, 2009 Free Software Foundation, Inc. |
b7b65b15 EZ |
3 | |
4 | This file is part of GNU Emacs. | |
5 | ||
6 | GNU Emacs is free software; you can redistribute it and/or modify | |
7 | it under the terms of the GNU General Public License as published by | |
8 | the Free Software Foundation; either version 2, or (at your option) | |
9 | any later version. | |
10 | ||
11 | GNU Emacs is distributed in the hope that it will be useful, | |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | GNU General Public License for more details. | |
15 | ||
16 | ||
17 | You should have received a copy of the GNU General Public License | |
18 | along with GNU Emacs; see the file COPYING. If not, write to | |
19 | the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, | |
20 | Boston, MA 02110-1301, USA. */ | |
21 | ||
2d6e4628 EZ |
22 | /* Written by Eli Zaretskii <eliz@gnu.org>. |
23 | ||
24 | A sequential implementation of the Unicode Bidirectional algorithm, | |
b7b65b15 EZ |
25 | as per UAX#9, a part of the Unicode Standard. |
26 | ||
27 | Unlike the reference and most other implementations, this one is | |
28 | designed to be called once for every character in the buffer. | |
29 | ||
30 | The main entry point is bidi_get_next_char_visually. Each time it | |
31 | is called, it finds the next character in the visual order, and | |
32 | returns its information in a special structure. The caller is then | |
33 | expected to process this character for display or any other | |
34 | purposes, and call bidi_get_next_char_visually for the next | |
35 | character. See the comments in bidi_get_next_char_visually for | |
36 | more details about its algorithm that finds the next visual-order | |
37 | character by resolving their levels on the fly. | |
38 | ||
89d3374a EZ |
39 | If you want to understand the code, you will have to read it |
40 | together with the relevant portions of UAX#9. The comments include | |
41 | references to UAX#9 rules, for that very reason. | |
42 | ||
b7b65b15 EZ |
43 | A note about references to UAX#9 rules: if the reference says |
44 | something like "X9/Retaining", it means that you need to refer to | |
45 | rule X9 and to its modifications decribed in the "Implementation | |
46 | Notes" section of UAX#9, under "Retaining Format Codes". */ | |
47 | ||
48 | #ifdef HAVE_CONFIG_H | |
49 | #include <config.h> | |
50 | #endif | |
51 | ||
52 | #include <stdio.h> | |
53 | ||
54 | #ifdef HAVE_STRING_H | |
55 | #include <string.h> | |
56 | #endif | |
57 | ||
58 | #include "lisp.h" | |
59 | #include "buffer.h" | |
60 | #include "character.h" | |
61 | #include "dispextern.h" | |
62 | ||
63 | static int bidi_initialized = 0; | |
64 | ||
65 | static Lisp_Object bidi_type_table; | |
66 | ||
e7402cb2 | 67 | /* FIXME: Remove these when bidi_explicit_dir_char uses a lookup table. */ |
b7b65b15 EZ |
68 | #define LRM_CHAR 0x200E |
69 | #define RLM_CHAR 0x200F | |
70 | #define LRE_CHAR 0x202A | |
71 | #define RLE_CHAR 0x202B | |
72 | #define PDF_CHAR 0x202C | |
73 | #define LRO_CHAR 0x202D | |
74 | #define RLO_CHAR 0x202E | |
75 | ||
b7b65b15 | 76 | #define BIDI_EOB -1 |
e7402cb2 | 77 | #define BIDI_BOB -2 /* FIXME: Is this needed? */ |
b7b65b15 | 78 | |
b7b65b15 EZ |
79 | /* Local data structures. (Look in dispextern.h for the rest.) */ |
80 | ||
81 | /* What we need to know about the current paragraph. */ | |
82 | struct bidi_paragraph_info { | |
83 | int start_bytepos; /* byte position where it begins */ | |
84 | int end_bytepos; /* byte position where it ends */ | |
85 | int embedding_level; /* its basic embedding level */ | |
86 | bidi_dir_t base_dir; /* its base direction */ | |
87 | }; | |
88 | ||
89 | /* Data type for describing the bidirectional character categories. */ | |
90 | typedef enum { | |
91 | UNKNOWN_BC, | |
92 | NEUTRAL, | |
93 | WEAK, | |
94 | STRONG | |
95 | } bidi_category_t; | |
96 | ||
97 | int bidi_ignore_explicit_marks_for_paragraph_level = 1; | |
98 | ||
6bff6497 EZ |
99 | static Lisp_Object fallback_paragraph_start_re, fallback_paragraph_separate_re; |
100 | static Lisp_Object Qparagraph_start, Qparagraph_separate; | |
b7b65b15 | 101 | |
b7b65b15 EZ |
102 | static void |
103 | bidi_initialize () | |
104 | { | |
105 | /* FIXME: This should come from the Unicode Database. */ | |
106 | struct { | |
107 | int from, to; | |
108 | bidi_type_t type; | |
109 | } bidi_type[] = | |
110 | { { 0x0000, 0x0008, WEAK_BN }, | |
111 | { 0x0009, 0x0000, NEUTRAL_S }, | |
112 | { 0x000A, 0x0000, NEUTRAL_B }, | |
113 | { 0x000B, 0x0000, NEUTRAL_S }, | |
114 | { 0x000C, 0x0000, NEUTRAL_WS }, | |
115 | { 0x000D, 0x0000, NEUTRAL_B }, | |
116 | { 0x000E, 0x001B, WEAK_BN }, | |
117 | { 0x001C, 0x001E, NEUTRAL_B }, | |
118 | { 0x001F, 0x0000, NEUTRAL_S }, | |
119 | { 0x0020, 0x0000, NEUTRAL_WS }, | |
120 | { 0x0021, 0x0022, NEUTRAL_ON }, | |
121 | { 0x0023, 0x0025, WEAK_ET }, | |
122 | { 0x0026, 0x002A, NEUTRAL_ON }, | |
e342a24d | 123 | { 0x002B, 0x0000, WEAK_ES }, |
b7b65b15 | 124 | { 0x002C, 0x0000, WEAK_CS }, |
e342a24d EZ |
125 | { 0x002D, 0x0000, WEAK_ES }, |
126 | { 0x002E, 0x002F, WEAK_CS }, | |
b7b65b15 EZ |
127 | { 0x0030, 0x0039, WEAK_EN }, |
128 | { 0x003A, 0x0000, WEAK_CS }, | |
129 | { 0x003B, 0x0040, NEUTRAL_ON }, | |
130 | { 0x005B, 0x0060, NEUTRAL_ON }, | |
131 | { 0x007B, 0x007E, NEUTRAL_ON }, | |
132 | { 0x007F, 0x0084, WEAK_BN }, | |
133 | { 0x0085, 0x0000, NEUTRAL_B }, | |
134 | { 0x0086, 0x009F, WEAK_BN }, | |
135 | { 0x00A0, 0x0000, WEAK_CS }, | |
136 | { 0x00A1, 0x0000, NEUTRAL_ON }, | |
137 | { 0x00A2, 0x00A5, WEAK_ET }, | |
138 | { 0x00A6, 0x00A9, NEUTRAL_ON }, | |
e342a24d EZ |
139 | { 0x00AB, 0x00AC, NEUTRAL_ON }, |
140 | { 0x00AD, 0x0000, WEAK_BN }, | |
141 | { 0x00AE, 0x00Af, NEUTRAL_ON }, | |
b7b65b15 EZ |
142 | { 0x00B0, 0x00B1, WEAK_ET }, |
143 | { 0x00B2, 0x00B3, WEAK_EN }, | |
144 | { 0x00B4, 0x0000, NEUTRAL_ON }, | |
145 | { 0x00B6, 0x00B8, NEUTRAL_ON }, | |
146 | { 0x00B9, 0x0000, WEAK_EN }, | |
147 | { 0x00BB, 0x00BF, NEUTRAL_ON }, | |
148 | { 0x00D7, 0x0000, NEUTRAL_ON }, | |
149 | { 0x00F7, 0x0000, NEUTRAL_ON }, | |
150 | { 0x02B9, 0x02BA, NEUTRAL_ON }, | |
151 | { 0x02C2, 0x02CF, NEUTRAL_ON }, | |
152 | { 0x02D2, 0x02DF, NEUTRAL_ON }, | |
153 | { 0x02E5, 0x02ED, NEUTRAL_ON }, | |
154 | { 0x0300, 0x036F, WEAK_NSM }, | |
155 | { 0x0374, 0x0375, NEUTRAL_ON }, | |
156 | { 0x037E, 0x0385, NEUTRAL_ON }, | |
157 | { 0x0387, 0x0000, NEUTRAL_ON }, | |
158 | { 0x03F6, 0x0000, NEUTRAL_ON }, | |
159 | { 0x0483, 0x0489, WEAK_NSM }, | |
160 | { 0x058A, 0x0000, NEUTRAL_ON }, | |
161 | { 0x0591, 0x05BD, WEAK_NSM }, | |
162 | { 0x05BE, 0x0000, STRONG_R }, | |
163 | { 0x05BF, 0x0000, WEAK_NSM }, | |
164 | { 0x05C0, 0x0000, STRONG_R }, | |
165 | { 0x05C1, 0x05C2, WEAK_NSM }, | |
166 | { 0x05C3, 0x0000, STRONG_R }, | |
e342a24d EZ |
167 | { 0x05C4, 0x05C5, WEAK_NSM }, |
168 | { 0x05C6, 0x0000, STRONG_R }, | |
169 | { 0x05C7, 0x0000, WEAK_NSM }, | |
b7b65b15 EZ |
170 | { 0x05D0, 0x05F4, STRONG_R }, |
171 | { 0x060C, 0x0000, WEAK_CS }, | |
172 | { 0x061B, 0x064A, STRONG_AL }, | |
173 | { 0x064B, 0x0655, WEAK_NSM }, | |
174 | { 0x0660, 0x0669, WEAK_AN }, | |
175 | { 0x066A, 0x0000, WEAK_ET }, | |
176 | { 0x066B, 0x066C, WEAK_AN }, | |
177 | { 0x066D, 0x066F, STRONG_AL }, | |
178 | { 0x0670, 0x0000, WEAK_NSM }, | |
179 | { 0x0671, 0x06D5, STRONG_AL }, | |
180 | { 0x06D6, 0x06DC, WEAK_NSM }, | |
181 | { 0x06DD, 0x0000, STRONG_AL }, | |
182 | { 0x06DE, 0x06E4, WEAK_NSM }, | |
183 | { 0x06E5, 0x06E6, STRONG_AL }, | |
184 | { 0x06E7, 0x06E8, WEAK_NSM }, | |
185 | { 0x06E9, 0x0000, NEUTRAL_ON }, | |
186 | { 0x06EA, 0x06ED, WEAK_NSM }, | |
187 | { 0x06F0, 0x06F9, WEAK_EN }, | |
188 | { 0x06FA, 0x070D, STRONG_AL }, | |
189 | { 0x070F, 0x0000, WEAK_BN }, | |
190 | { 0x0710, 0x0000, STRONG_AL }, | |
191 | { 0x0711, 0x0000, WEAK_NSM }, | |
192 | { 0x0712, 0x072C, STRONG_AL }, | |
193 | { 0x0730, 0x074A, WEAK_NSM }, | |
194 | { 0x0780, 0x07A5, STRONG_AL }, | |
195 | { 0x07A6, 0x07B0, WEAK_NSM }, | |
196 | { 0x07B1, 0x0000, STRONG_AL }, | |
197 | { 0x0901, 0x0902, WEAK_NSM }, | |
198 | { 0x093C, 0x0000, WEAK_NSM }, | |
199 | { 0x0941, 0x0948, WEAK_NSM }, | |
200 | { 0x094D, 0x0000, WEAK_NSM }, | |
201 | { 0x0951, 0x0954, WEAK_NSM }, | |
202 | { 0x0962, 0x0963, WEAK_NSM }, | |
203 | { 0x0981, 0x0000, WEAK_NSM }, | |
204 | { 0x09BC, 0x0000, WEAK_NSM }, | |
205 | { 0x09C1, 0x09C4, WEAK_NSM }, | |
206 | { 0x09CD, 0x0000, WEAK_NSM }, | |
207 | { 0x09E2, 0x09E3, WEAK_NSM }, | |
208 | { 0x09F2, 0x09F3, WEAK_ET }, | |
209 | { 0x0A02, 0x0000, WEAK_NSM }, | |
210 | { 0x0A3C, 0x0000, WEAK_NSM }, | |
211 | { 0x0A41, 0x0A4D, WEAK_NSM }, | |
212 | { 0x0A70, 0x0A71, WEAK_NSM }, | |
213 | { 0x0A81, 0x0A82, WEAK_NSM }, | |
214 | { 0x0ABC, 0x0000, WEAK_NSM }, | |
215 | { 0x0AC1, 0x0AC8, WEAK_NSM }, | |
216 | { 0x0ACD, 0x0000, WEAK_NSM }, | |
217 | { 0x0B01, 0x0000, WEAK_NSM }, | |
218 | { 0x0B3C, 0x0000, WEAK_NSM }, | |
219 | { 0x0B3F, 0x0000, WEAK_NSM }, | |
220 | { 0x0B41, 0x0B43, WEAK_NSM }, | |
221 | { 0x0B4D, 0x0B56, WEAK_NSM }, | |
222 | { 0x0B82, 0x0000, WEAK_NSM }, | |
223 | { 0x0BC0, 0x0000, WEAK_NSM }, | |
224 | { 0x0BCD, 0x0000, WEAK_NSM }, | |
225 | { 0x0C3E, 0x0C40, WEAK_NSM }, | |
226 | { 0x0C46, 0x0C56, WEAK_NSM }, | |
227 | { 0x0CBF, 0x0000, WEAK_NSM }, | |
228 | { 0x0CC6, 0x0000, WEAK_NSM }, | |
229 | { 0x0CCC, 0x0CCD, WEAK_NSM }, | |
230 | { 0x0D41, 0x0D43, WEAK_NSM }, | |
231 | { 0x0D4D, 0x0000, WEAK_NSM }, | |
232 | { 0x0DCA, 0x0000, WEAK_NSM }, | |
233 | { 0x0DD2, 0x0DD6, WEAK_NSM }, | |
234 | { 0x0E31, 0x0000, WEAK_NSM }, | |
235 | { 0x0E34, 0x0E3A, WEAK_NSM }, | |
236 | { 0x0E3F, 0x0000, WEAK_ET }, | |
237 | { 0x0E47, 0x0E4E, WEAK_NSM }, | |
238 | { 0x0EB1, 0x0000, WEAK_NSM }, | |
239 | { 0x0EB4, 0x0EBC, WEAK_NSM }, | |
240 | { 0x0EC8, 0x0ECD, WEAK_NSM }, | |
241 | { 0x0F18, 0x0F19, WEAK_NSM }, | |
242 | { 0x0F35, 0x0000, WEAK_NSM }, | |
243 | { 0x0F37, 0x0000, WEAK_NSM }, | |
244 | { 0x0F39, 0x0000, WEAK_NSM }, | |
245 | { 0x0F3A, 0x0F3D, NEUTRAL_ON }, | |
246 | { 0x0F71, 0x0F7E, WEAK_NSM }, | |
247 | { 0x0F80, 0x0F84, WEAK_NSM }, | |
248 | { 0x0F86, 0x0F87, WEAK_NSM }, | |
249 | { 0x0F90, 0x0FBC, WEAK_NSM }, | |
250 | { 0x0FC6, 0x0000, WEAK_NSM }, | |
251 | { 0x102D, 0x1030, WEAK_NSM }, | |
252 | { 0x1032, 0x1037, WEAK_NSM }, | |
253 | { 0x1039, 0x0000, WEAK_NSM }, | |
254 | { 0x1058, 0x1059, WEAK_NSM }, | |
255 | { 0x1680, 0x0000, NEUTRAL_WS }, | |
256 | { 0x169B, 0x169C, NEUTRAL_ON }, | |
257 | { 0x1712, 0x1714, WEAK_NSM }, | |
258 | { 0x1732, 0x1734, WEAK_NSM }, | |
259 | { 0x1752, 0x1753, WEAK_NSM }, | |
260 | { 0x1772, 0x1773, WEAK_NSM }, | |
261 | { 0x17B7, 0x17BD, WEAK_NSM }, | |
262 | { 0x17C6, 0x0000, WEAK_NSM }, | |
263 | { 0x17C9, 0x17D3, WEAK_NSM }, | |
264 | { 0x17DB, 0x0000, WEAK_ET }, | |
265 | { 0x1800, 0x180A, NEUTRAL_ON }, | |
266 | { 0x180B, 0x180D, WEAK_NSM }, | |
267 | { 0x180E, 0x0000, WEAK_BN }, | |
268 | { 0x18A9, 0x0000, WEAK_NSM }, | |
269 | { 0x1FBD, 0x0000, NEUTRAL_ON }, | |
270 | { 0x1FBF, 0x1FC1, NEUTRAL_ON }, | |
271 | { 0x1FCD, 0x1FCF, NEUTRAL_ON }, | |
272 | { 0x1FDD, 0x1FDF, NEUTRAL_ON }, | |
273 | { 0x1FED, 0x1FEF, NEUTRAL_ON }, | |
274 | { 0x1FFD, 0x1FFE, NEUTRAL_ON }, | |
275 | { 0x2000, 0x200A, NEUTRAL_WS }, | |
276 | { 0x200B, 0x200D, WEAK_BN }, | |
277 | { 0x200F, 0x0000, STRONG_R }, | |
278 | { 0x2010, 0x2027, NEUTRAL_ON }, | |
279 | { 0x2028, 0x0000, NEUTRAL_WS }, | |
280 | { 0x2029, 0x0000, NEUTRAL_B }, | |
281 | { 0x202A, 0x0000, LRE }, | |
282 | { 0x202B, 0x0000, RLE }, | |
283 | { 0x202C, 0x0000, PDF }, | |
284 | { 0x202D, 0x0000, LRO }, | |
285 | { 0x202E, 0x0000, RLO }, | |
286 | { 0x202F, 0x0000, NEUTRAL_WS }, | |
287 | { 0x2030, 0x2034, WEAK_ET }, | |
288 | { 0x2035, 0x2057, NEUTRAL_ON }, | |
289 | { 0x205F, 0x0000, NEUTRAL_WS }, | |
290 | { 0x2060, 0x206F, WEAK_BN }, | |
291 | { 0x2070, 0x0000, WEAK_EN }, | |
292 | { 0x2074, 0x2079, WEAK_EN }, | |
293 | { 0x207A, 0x207B, WEAK_ET }, | |
294 | { 0x207C, 0x207E, NEUTRAL_ON }, | |
295 | { 0x2080, 0x2089, WEAK_EN }, | |
296 | { 0x208A, 0x208B, WEAK_ET }, | |
297 | { 0x208C, 0x208E, NEUTRAL_ON }, | |
298 | { 0x20A0, 0x20B1, WEAK_ET }, | |
299 | { 0x20D0, 0x20EA, WEAK_NSM }, | |
300 | { 0x2100, 0x2101, NEUTRAL_ON }, | |
301 | { 0x2103, 0x2106, NEUTRAL_ON }, | |
302 | { 0x2108, 0x2109, NEUTRAL_ON }, | |
303 | { 0x2114, 0x0000, NEUTRAL_ON }, | |
304 | { 0x2116, 0x2118, NEUTRAL_ON }, | |
305 | { 0x211E, 0x2123, NEUTRAL_ON }, | |
306 | { 0x2125, 0x0000, NEUTRAL_ON }, | |
307 | { 0x2127, 0x0000, NEUTRAL_ON }, | |
308 | { 0x2129, 0x0000, NEUTRAL_ON }, | |
309 | { 0x212E, 0x0000, WEAK_ET }, | |
310 | { 0x2132, 0x0000, NEUTRAL_ON }, | |
311 | { 0x213A, 0x0000, NEUTRAL_ON }, | |
312 | { 0x2140, 0x2144, NEUTRAL_ON }, | |
313 | { 0x214A, 0x215F, NEUTRAL_ON }, | |
314 | { 0x2190, 0x2211, NEUTRAL_ON }, | |
315 | { 0x2212, 0x2213, WEAK_ET }, | |
316 | { 0x2214, 0x2335, NEUTRAL_ON }, | |
317 | { 0x237B, 0x2394, NEUTRAL_ON }, | |
318 | { 0x2396, 0x244A, NEUTRAL_ON }, | |
319 | { 0x2460, 0x249B, WEAK_EN }, | |
320 | { 0x24EA, 0x0000, WEAK_EN }, | |
321 | { 0x24EB, 0x2FFB, NEUTRAL_ON }, | |
322 | { 0x3000, 0x0000, NEUTRAL_WS }, | |
323 | { 0x3001, 0x3004, NEUTRAL_ON }, | |
324 | { 0x3008, 0x3020, NEUTRAL_ON }, | |
325 | { 0x302A, 0x302F, WEAK_NSM }, | |
326 | { 0x3030, 0x0000, NEUTRAL_ON }, | |
327 | { 0x3036, 0x3037, NEUTRAL_ON }, | |
328 | { 0x303D, 0x303F, NEUTRAL_ON }, | |
329 | { 0x3099, 0x309A, WEAK_NSM }, | |
330 | { 0x309B, 0x309C, NEUTRAL_ON }, | |
331 | { 0x30A0, 0x0000, NEUTRAL_ON }, | |
332 | { 0x30FB, 0x0000, NEUTRAL_ON }, | |
333 | { 0x3251, 0x325F, NEUTRAL_ON }, | |
334 | { 0x32B1, 0x32BF, NEUTRAL_ON }, | |
335 | { 0xA490, 0xA4C6, NEUTRAL_ON }, | |
336 | { 0xFB1D, 0x0000, STRONG_R }, | |
337 | { 0xFB1E, 0x0000, WEAK_NSM }, | |
338 | { 0xFB1F, 0xFB28, STRONG_R }, | |
339 | { 0xFB29, 0x0000, WEAK_ET }, | |
340 | { 0xFB2A, 0xFB4F, STRONG_R }, | |
341 | { 0xFB50, 0xFD3D, STRONG_AL }, | |
342 | { 0xFD3E, 0xFD3F, NEUTRAL_ON }, | |
343 | { 0xFD50, 0xFDFC, STRONG_AL }, | |
344 | { 0xFE00, 0xFE23, WEAK_NSM }, | |
345 | { 0xFE30, 0xFE4F, NEUTRAL_ON }, | |
346 | { 0xFE50, 0x0000, WEAK_CS }, | |
347 | { 0xFE51, 0x0000, NEUTRAL_ON }, | |
348 | { 0xFE52, 0x0000, WEAK_CS }, | |
349 | { 0xFE54, 0x0000, NEUTRAL_ON }, | |
350 | { 0xFE55, 0x0000, WEAK_CS }, | |
351 | { 0xFE56, 0xFE5E, NEUTRAL_ON }, | |
352 | { 0xFE5F, 0x0000, WEAK_ET }, | |
353 | { 0xFE60, 0xFE61, NEUTRAL_ON }, | |
354 | { 0xFE62, 0xFE63, WEAK_ET }, | |
355 | { 0xFE64, 0xFE68, NEUTRAL_ON }, | |
356 | { 0xFE69, 0xFE6A, WEAK_ET }, | |
357 | { 0xFE6B, 0x0000, NEUTRAL_ON }, | |
358 | { 0xFE70, 0xFEFC, STRONG_AL }, | |
359 | { 0xFEFF, 0x0000, WEAK_BN }, | |
360 | { 0xFF01, 0xFF02, NEUTRAL_ON }, | |
361 | { 0xFF03, 0xFF05, WEAK_ET }, | |
362 | { 0xFF06, 0xFF0A, NEUTRAL_ON }, | |
363 | { 0xFF0B, 0x0000, WEAK_ET }, | |
364 | { 0xFF0C, 0x0000, WEAK_CS }, | |
365 | { 0xFF0D, 0x0000, WEAK_ET }, | |
366 | { 0xFF0E, 0x0000, WEAK_CS }, | |
367 | { 0xFF0F, 0x0000, WEAK_ES }, | |
368 | { 0xFF10, 0xFF19, WEAK_EN }, | |
369 | { 0xFF1A, 0x0000, WEAK_CS }, | |
370 | { 0xFF1B, 0xFF20, NEUTRAL_ON }, | |
371 | { 0xFF3B, 0xFF40, NEUTRAL_ON }, | |
372 | { 0xFF5B, 0xFF65, NEUTRAL_ON }, | |
373 | { 0xFFE0, 0xFFE1, WEAK_ET }, | |
374 | { 0xFFE2, 0xFFE4, NEUTRAL_ON }, | |
375 | { 0xFFE5, 0xFFE6, WEAK_ET }, | |
376 | { 0xFFE8, 0xFFEE, NEUTRAL_ON }, | |
377 | { 0xFFF9, 0xFFFB, WEAK_BN }, | |
378 | { 0xFFFC, 0xFFFD, NEUTRAL_ON }, | |
379 | { 0x1D167, 0x1D169, WEAK_NSM }, | |
380 | { 0x1D173, 0x1D17A, WEAK_BN }, | |
381 | { 0x1D17B, 0x1D182, WEAK_NSM }, | |
382 | { 0x1D185, 0x1D18B, WEAK_NSM }, | |
383 | { 0x1D1AA, 0x1D1AD, WEAK_NSM }, | |
384 | { 0x1D7CE, 0x1D7FF, WEAK_EN }, | |
385 | { 0xE0001, 0xE007F, WEAK_BN } }; | |
386 | int i; | |
387 | ||
388 | bidi_type_table = Fmake_char_table (Qnil, make_number (STRONG_L)); | |
2d6e4628 | 389 | staticpro (&bidi_type_table); |
b7b65b15 EZ |
390 | |
391 | for (i = 0; i < sizeof bidi_type / sizeof bidi_type[0]; i++) | |
f44e260c EZ |
392 | char_table_set_range (bidi_type_table, bidi_type[i].from, |
393 | bidi_type[i].to ? bidi_type[i].to : bidi_type[i].from, | |
b7b65b15 | 394 | make_number (bidi_type[i].type)); |
6bff6497 EZ |
395 | |
396 | fallback_paragraph_start_re = | |
397 | XSYMBOL (Fintern_soft (build_string ("paragraph-start"), Qnil))->value; | |
398 | if (!STRINGP (fallback_paragraph_start_re)) | |
399 | fallback_paragraph_start_re = build_string ("\f\\|[ \t]*$"); | |
400 | staticpro (&fallback_paragraph_start_re); | |
401 | Qparagraph_start = intern ("paragraph-start"); | |
402 | staticpro (&Qparagraph_start); | |
403 | fallback_paragraph_separate_re = | |
404 | XSYMBOL (Fintern_soft (build_string ("paragraph-separate"), Qnil))->value; | |
405 | if (!STRINGP (fallback_paragraph_separate_re)) | |
406 | fallback_paragraph_separate_re = build_string ("[ \t\f]*$"); | |
407 | staticpro (&fallback_paragraph_separate_re); | |
408 | Qparagraph_separate = intern ("paragraph-separate"); | |
409 | staticpro (&Qparagraph_separate); | |
b7b65b15 EZ |
410 | bidi_initialized = 1; |
411 | } | |
412 | ||
6bff6497 EZ |
413 | /* Return the bidi type of a character CH, subject to the current |
414 | directional OVERRIDE. */ | |
b7b65b15 | 415 | bidi_type_t |
6bff6497 | 416 | bidi_get_type (int ch, bidi_dir_t override) |
b7b65b15 | 417 | { |
6bff6497 EZ |
418 | bidi_type_t default_type; |
419 | ||
e7402cb2 EZ |
420 | if (ch == BIDI_EOB) |
421 | return NEUTRAL_B; | |
e342a24d EZ |
422 | if (ch < 0 || ch > MAX_CHAR) |
423 | abort (); | |
6bff6497 EZ |
424 | |
425 | default_type = (bidi_type_t) XINT (CHAR_TABLE_REF (bidi_type_table, ch)); | |
426 | ||
427 | if (override == NEUTRAL_DIR) | |
428 | return default_type; | |
429 | ||
430 | switch (default_type) | |
431 | { | |
432 | /* Although UAX#9 does not tell, it doesn't make sense to | |
433 | override NEUTRAL_B and LRM/RLM characters. */ | |
434 | case NEUTRAL_B: | |
435 | case LRE: | |
436 | case LRO: | |
437 | case RLE: | |
438 | case RLO: | |
439 | case PDF: | |
440 | return default_type; | |
441 | default: | |
442 | switch (ch) | |
443 | { | |
444 | case LRM_CHAR: | |
445 | case RLM_CHAR: | |
446 | return default_type; | |
447 | default: | |
448 | if (override == L2R) /* X6 */ | |
449 | return STRONG_L; | |
450 | else if (override == R2L) | |
451 | return STRONG_R; | |
452 | else | |
453 | abort (); /* can't happen: handled above */ | |
454 | } | |
455 | } | |
b7b65b15 EZ |
456 | } |
457 | ||
2d6e4628 EZ |
458 | void |
459 | bidi_check_type (bidi_type_t type) | |
460 | { | |
461 | if (type < UNKNOWN_BT || type > NEUTRAL_ON) | |
462 | abort (); | |
463 | } | |
464 | ||
b7b65b15 EZ |
465 | /* Given a bidi TYPE of a character, return its category. */ |
466 | bidi_category_t | |
467 | bidi_get_category (bidi_type_t type) | |
468 | { | |
469 | switch (type) | |
470 | { | |
471 | case UNKNOWN_BT: | |
472 | return UNKNOWN_BC; | |
473 | case STRONG_L: | |
474 | case STRONG_R: | |
475 | case STRONG_AL: | |
476 | case LRE: | |
477 | case LRO: | |
478 | case RLE: | |
479 | case RLO: | |
480 | return STRONG; | |
481 | case PDF: /* ??? really?? */ | |
482 | case WEAK_EN: | |
483 | case WEAK_ES: | |
484 | case WEAK_ET: | |
485 | case WEAK_AN: | |
486 | case WEAK_CS: | |
487 | case WEAK_NSM: | |
488 | case WEAK_BN: | |
489 | return WEAK; | |
490 | case NEUTRAL_B: | |
491 | case NEUTRAL_S: | |
492 | case NEUTRAL_WS: | |
493 | case NEUTRAL_ON: | |
494 | return NEUTRAL; | |
495 | default: | |
496 | abort (); | |
497 | } | |
498 | } | |
499 | ||
e342a24d EZ |
500 | /* Return the mirrored character of C, if any. |
501 | ||
502 | Note: The conditions in UAX#9 clause L4 must be tested by the | |
503 | caller. */ | |
b7b65b15 EZ |
504 | /* FIXME: exceedingly temporary! Should consult the Unicode database |
505 | of character properties. */ | |
506 | int | |
507 | bidi_mirror_char (int c) | |
508 | { | |
509 | static const char mirrored_pairs[] = "()<>[]{}"; | |
510 | const char *p = strchr (mirrored_pairs, c); | |
511 | ||
512 | if (p) | |
513 | { | |
514 | size_t i = p - mirrored_pairs; | |
515 | ||
516 | if ((i & 1) == 0) | |
517 | return mirrored_pairs[i + 1]; | |
518 | else | |
519 | return mirrored_pairs[i - 1]; | |
520 | } | |
521 | return c; | |
522 | } | |
523 | ||
524 | /* Copy the bidi iterator from FROM to TO. To save cycles, this only | |
525 | copies the part of the level stack that is actually in use. */ | |
526 | static inline void | |
527 | bidi_copy_it (struct bidi_it *to, struct bidi_it *from) | |
528 | { | |
9c82e145 | 529 | int save_first_elt = to->first_elt; |
b7b65b15 EZ |
530 | int i; |
531 | ||
532 | /* Copy everything except the level stack. */ | |
533 | memcpy (to, from, ((int)&((struct bidi_it *)0)->level_stack[0])); | |
e5a2fec7 | 534 | /* Don't copy FIRST_ELT flag. */ |
9c82e145 EZ |
535 | to->first_elt = save_first_elt; |
536 | if (to->first_elt != 0 && to->first_elt != 1) | |
537 | to->first_elt = 0; | |
b7b65b15 EZ |
538 | |
539 | /* Copy the active part of the level stack. */ | |
540 | to->level_stack[0] = from->level_stack[0]; /* level zero is always in use */ | |
541 | for (i = 1; i <= from->stack_idx; i++) | |
542 | to->level_stack[i] = from->level_stack[i]; | |
543 | } | |
544 | ||
545 | /* Caching the bidi iterator states. */ | |
546 | ||
547 | static struct bidi_it bidi_cache[1000]; /* FIXME: make this dynamically allocated! */ | |
548 | static int bidi_cache_idx; | |
549 | static int bidi_cache_last_idx; | |
550 | ||
551 | static inline void | |
552 | bidi_cache_reset (void) | |
553 | { | |
554 | bidi_cache_idx = 0; | |
555 | bidi_cache_last_idx = -1; | |
556 | } | |
557 | ||
558 | static inline void | |
559 | bidi_cache_fetch_state (int idx, struct bidi_it *bidi_it) | |
560 | { | |
561 | int current_scan_dir = bidi_it->scan_dir; | |
562 | ||
563 | if (idx < 0 || idx >= bidi_cache_idx) | |
564 | abort (); | |
565 | ||
566 | bidi_copy_it (bidi_it, &bidi_cache[idx]); | |
567 | bidi_it->scan_dir = current_scan_dir; | |
568 | bidi_cache_last_idx = idx; | |
569 | } | |
570 | ||
571 | /* Find a cached state with a given CHARPOS and resolved embedding | |
572 | level less or equal to LEVEL. if LEVEL is -1, disregard the | |
573 | resolved levels in cached states. DIR, if non-zero, means search | |
574 | in that direction from the last cache hit. */ | |
575 | static inline int | |
576 | bidi_cache_search (int charpos, int level, int dir) | |
577 | { | |
578 | int i, i_start; | |
579 | ||
580 | if (bidi_cache_idx) | |
581 | { | |
582 | if (charpos < bidi_cache[bidi_cache_last_idx].charpos) | |
583 | dir = -1; | |
584 | else if (charpos > bidi_cache[bidi_cache_last_idx].charpos) | |
585 | dir = 1; | |
586 | if (dir) | |
587 | i_start = bidi_cache_last_idx; | |
588 | else | |
589 | { | |
590 | dir = -1; | |
591 | i_start = bidi_cache_idx - 1; | |
592 | } | |
593 | ||
594 | if (dir < 0) | |
595 | { | |
596 | /* Linear search for now; FIXME! */ | |
597 | for (i = i_start; i >= 0; i--) | |
598 | if (bidi_cache[i].charpos == charpos | |
599 | && (level == -1 || bidi_cache[i].resolved_level <= level)) | |
600 | return i; | |
601 | } | |
602 | else | |
603 | { | |
604 | for (i = i_start; i < bidi_cache_idx; i++) | |
605 | if (bidi_cache[i].charpos == charpos | |
606 | && (level == -1 || bidi_cache[i].resolved_level <= level)) | |
607 | return i; | |
608 | } | |
609 | } | |
610 | ||
611 | return -1; | |
612 | } | |
613 | ||
614 | /* Find a cached state where the resolved level changes to a value | |
615 | that is lower than LEVEL, and return its cache slot index. DIR is | |
616 | the direction to search, starting with the last used cache slot. | |
617 | BEFORE, if non-zero, means return the index of the slot that is | |
618 | ``before'' the level change in the search direction. That is, | |
619 | given the cached levels like this: | |
620 | ||
621 | 1122333442211 | |
622 | AB C | |
623 | ||
624 | and assuming we are at the position cached at the slot marked with | |
625 | C, searching backwards (DIR = -1) for LEVEL = 2 will return the | |
626 | index of slot B or A, depending whether BEFORE is, respectively, | |
627 | non-zero or zero. */ | |
628 | static int | |
629 | bidi_cache_find_level_change (int level, int dir, int before) | |
630 | { | |
631 | if (bidi_cache_idx) | |
632 | { | |
633 | int i = dir ? bidi_cache_last_idx : bidi_cache_idx - 1; | |
634 | int incr = before ? 1 : 0; | |
635 | ||
636 | if (!dir) | |
637 | dir = -1; | |
638 | else if (!incr) | |
639 | i += dir; | |
640 | ||
641 | if (dir < 0) | |
642 | { | |
643 | while (i >= incr) | |
644 | { | |
645 | if (bidi_cache[i - incr].resolved_level >= 0 | |
646 | && bidi_cache[i - incr].resolved_level < level) | |
647 | return i; | |
648 | i--; | |
649 | } | |
650 | } | |
651 | else | |
652 | { | |
653 | while (i < bidi_cache_idx - incr) | |
654 | { | |
655 | if (bidi_cache[i + incr].resolved_level >= 0 | |
656 | && bidi_cache[i + incr].resolved_level < level) | |
657 | return i; | |
658 | i++; | |
659 | } | |
660 | } | |
661 | } | |
662 | ||
663 | return -1; | |
664 | } | |
665 | ||
666 | static inline void | |
667 | bidi_cache_iterator_state (struct bidi_it *bidi_it, int resolved) | |
668 | { | |
669 | int idx; | |
670 | ||
671 | /* We should never cache on backward scans. */ | |
672 | if (bidi_it->scan_dir == -1) | |
673 | abort (); | |
674 | idx = bidi_cache_search (bidi_it->charpos, -1, 1); | |
675 | ||
676 | if (idx < 0) | |
677 | { | |
678 | idx = bidi_cache_idx; | |
e5a2fec7 | 679 | /* Don't overrun the cache limit. */ |
b7b65b15 EZ |
680 | if (idx > sizeof (bidi_cache) / sizeof (bidi_cache[0]) - 1) |
681 | abort (); | |
e5a2fec7 EZ |
682 | /* Don't violate cache integrity: character positions should |
683 | correspond to cache positions 1:1. */ | |
684 | if (idx > 0 && bidi_it->charpos != bidi_cache[idx - 1].charpos + 1) | |
685 | abort (); | |
b7b65b15 EZ |
686 | bidi_copy_it (&bidi_cache[idx], bidi_it); |
687 | if (!resolved) | |
688 | bidi_cache[idx].resolved_level = -1; | |
e5a2fec7 | 689 | bidi_cache[idx].new_paragraph = 0; |
b7b65b15 EZ |
690 | } |
691 | else | |
692 | { | |
693 | /* Copy only the members which could have changed, to avoid | |
694 | costly copying of the entire struct. */ | |
695 | bidi_cache[idx].type = bidi_it->type; | |
2d6e4628 | 696 | bidi_check_type (bidi_it->type); |
89d3374a EZ |
697 | bidi_cache[idx].type_after_w1 = bidi_it->type_after_w1; |
698 | bidi_check_type (bidi_it->type_after_w1); | |
b7b65b15 EZ |
699 | if (resolved) |
700 | bidi_cache[idx].resolved_level = bidi_it->resolved_level; | |
701 | else | |
702 | bidi_cache[idx].resolved_level = -1; | |
703 | bidi_cache[idx].invalid_levels = bidi_it->invalid_levels; | |
704 | bidi_cache[idx].invalid_rl_levels = bidi_it->invalid_rl_levels; | |
705 | bidi_cache[idx].next_for_neutral = bidi_it->next_for_neutral; | |
706 | bidi_cache[idx].next_for_ws = bidi_it->next_for_ws; | |
707 | bidi_cache[idx].ignore_bn_limit = bidi_it->ignore_bn_limit; | |
708 | } | |
709 | ||
710 | bidi_cache_last_idx = idx; | |
711 | if (idx >= bidi_cache_idx) | |
712 | bidi_cache_idx = idx + 1; | |
713 | } | |
714 | ||
715 | static inline bidi_type_t | |
716 | bidi_cache_find (int charpos, int level, struct bidi_it *bidi_it) | |
717 | { | |
718 | int i = bidi_cache_search (charpos, level, bidi_it->scan_dir); | |
719 | ||
720 | if (i >= 0) | |
721 | { | |
722 | bidi_dir_t current_scan_dir = bidi_it->scan_dir; | |
723 | ||
724 | *bidi_it = bidi_cache[i]; | |
725 | bidi_cache_last_idx = i; | |
726 | /* Don't let scan direction from from the cached state override | |
727 | the current scan direction. */ | |
728 | bidi_it->scan_dir = current_scan_dir; | |
729 | return bidi_it->type; | |
730 | } | |
731 | ||
732 | return UNKNOWN_BT; | |
733 | } | |
734 | ||
735 | static inline int | |
736 | bidi_peek_at_next_level (struct bidi_it *bidi_it) | |
737 | { | |
738 | if (bidi_cache_idx == 0 || bidi_cache_last_idx == -1) | |
739 | abort (); | |
740 | return bidi_cache[bidi_cache_last_idx + bidi_it->scan_dir].resolved_level; | |
741 | } | |
742 | ||
be39f003 EZ |
743 | /* Check if buffer position CHARPOS/BYTEPOS is the end of a paragraph. |
744 | Value is the non-negative length of the paragraph separator | |
745 | following the buffer position, -1 if position is at the beginning | |
746 | of a new paragraph, or -2 if position is neither at beginning nor | |
747 | at end of a paragraph. */ | |
748 | EMACS_INT | |
6bff6497 | 749 | bidi_at_paragraph_end (EMACS_INT charpos, EMACS_INT bytepos) |
b7b65b15 | 750 | { |
be39f003 EZ |
751 | Lisp_Object sep_re = Fbuffer_local_value (Qparagraph_separate, |
752 | Fcurrent_buffer ()); | |
753 | Lisp_Object start_re = Fbuffer_local_value (Qparagraph_start, | |
754 | Fcurrent_buffer ()); | |
755 | EMACS_INT val; | |
756 | ||
757 | if (!STRINGP (sep_re)) | |
758 | sep_re = fallback_paragraph_separate_re; | |
759 | if (!STRINGP (start_re)) | |
760 | start_re = fallback_paragraph_start_re; | |
761 | ||
762 | val = fast_looking_at (sep_re, charpos, bytepos, ZV, ZV_BYTE, Qnil); | |
763 | if (val < 0) | |
764 | { | |
765 | if (fast_looking_at (start_re, charpos, bytepos, ZV, ZV_BYTE, Qnil) >= 0) | |
766 | val = -1; | |
767 | else | |
768 | val = -2; | |
769 | } | |
b7b65b15 | 770 | |
be39f003 | 771 | return val; |
b7b65b15 EZ |
772 | } |
773 | ||
774 | /* Determine the start-of-run (sor) directional type given the two | |
775 | embedding levels on either side of the run boundary. Also, update | |
776 | the saved info about previously seen characters, since that info is | |
777 | generally valid for a single level run. */ | |
778 | static inline void | |
779 | bidi_set_sor_type (struct bidi_it *bidi_it, int level_before, int level_after) | |
780 | { | |
781 | int higher_level = level_before > level_after ? level_before : level_after; | |
782 | ||
783 | /* The prev_was_pdf gork is required for when we have several PDFs | |
784 | in a row. In that case, we want to compute the sor type for the | |
785 | next level run only once: when we see the first PDF. That's | |
786 | because the sor type depends only on the higher of the two levels | |
787 | that we find on the two sides of the level boundary (see UAX#9, | |
788 | clause X10), and so we don't need to know the final embedding | |
789 | level to which we descend after processing all the PDFs. */ | |
e342a24d | 790 | if (!bidi_it->prev_was_pdf || level_before < level_after) |
b7b65b15 EZ |
791 | /* FIXME: should the default sor direction be user selectable? */ |
792 | bidi_it->sor = (higher_level & 1) != 0 ? R2L : L2R; | |
793 | if (level_before > level_after) | |
794 | bidi_it->prev_was_pdf = 1; | |
795 | ||
796 | bidi_it->prev.type = UNKNOWN_BT; | |
89d3374a EZ |
797 | bidi_it->last_strong.type = bidi_it->last_strong.type_after_w1 = |
798 | bidi_it->last_strong.orig_type = UNKNOWN_BT; | |
b7b65b15 EZ |
799 | bidi_it->prev_for_neutral.type = bidi_it->sor == R2L ? STRONG_R : STRONG_L; |
800 | bidi_it->prev_for_neutral.charpos = bidi_it->charpos; | |
801 | bidi_it->prev_for_neutral.bytepos = bidi_it->bytepos; | |
89d3374a EZ |
802 | bidi_it->next_for_neutral.type = bidi_it->next_for_neutral.type_after_w1 = |
803 | bidi_it->next_for_neutral.orig_type = UNKNOWN_BT; | |
b7b65b15 EZ |
804 | bidi_it->ignore_bn_limit = 0; /* meaning it's unknown */ |
805 | } | |
806 | ||
6bff6497 | 807 | static void |
be39f003 EZ |
808 | bidi_line_init (struct bidi_it *bidi_it) |
809 | { | |
810 | bidi_it->scan_dir = 1; /* FIXME: do we need to have control on this? */ | |
811 | bidi_it->resolved_level = bidi_it->level_stack[0].level; | |
812 | bidi_it->level_stack[0].override = NEUTRAL_DIR; /* X1 */ | |
813 | bidi_it->invalid_levels = 0; | |
814 | bidi_it->invalid_rl_levels = -1; | |
815 | bidi_it->next_en_pos = -1; | |
816 | bidi_it->next_for_ws.type = UNKNOWN_BT; | |
b44d9321 EZ |
817 | bidi_set_sor_type (bidi_it, |
818 | bidi_it->paragraph_dir == R2L ? 1 : 0, | |
be39f003 EZ |
819 | bidi_it->level_stack[0].level); /* X10 */ |
820 | ||
821 | bidi_cache_reset (); | |
822 | } | |
823 | ||
824 | /* Find the beginning of this paragraph by looking back in the buffer. | |
825 | Value is the byte position of the paragraph's beginning. */ | |
826 | static EMACS_INT | |
b44d9321 | 827 | bidi_find_paragraph_start (EMACS_INT pos, EMACS_INT pos_byte) |
6bff6497 | 828 | { |
be39f003 | 829 | Lisp_Object re = Fbuffer_local_value (Qparagraph_start, Fcurrent_buffer ()); |
6bff6497 EZ |
830 | EMACS_INT limit = ZV, limit_byte = ZV_BYTE; |
831 | ||
832 | if (!STRINGP (re)) | |
833 | re = fallback_paragraph_start_re; | |
834 | while (pos_byte > BEGV_BYTE | |
835 | && fast_looking_at (re, pos, pos_byte, limit, limit_byte, Qnil) < 0) | |
836 | { | |
be39f003 EZ |
837 | pos = find_next_newline_no_quit (pos - 1, -1); |
838 | pos_byte = CHAR_TO_BYTE (pos); | |
6bff6497 | 839 | } |
be39f003 | 840 | return pos_byte; |
6bff6497 EZ |
841 | } |
842 | ||
be39f003 | 843 | /* Determine the direction, a.k.a. base embedding level, of the |
b44d9321 EZ |
844 | paragraph we are about to iterate through. If DIR is either L2R or |
845 | R2L, just use that. Otherwise, determine the paragraph direction | |
846 | from the first strong character of the paragraph. | |
847 | ||
848 | Note that this gives the paragraph separator the same direction as | |
849 | the preceding paragraph, even though Emacs generally views the | |
850 | separartor as not belonging to any paragraph. */ | |
b7b65b15 EZ |
851 | void |
852 | bidi_paragraph_init (bidi_dir_t dir, struct bidi_it *bidi_it) | |
853 | { | |
6bff6497 | 854 | EMACS_INT bytepos = bidi_it->bytepos; |
e7402cb2 | 855 | |
9c82e145 EZ |
856 | /* We should never be called at EOB or before BEGV. */ |
857 | if (bytepos >= ZV_BYTE || bytepos < BEGV_BYTE) | |
858 | abort (); | |
859 | ||
be39f003 EZ |
860 | if (dir == L2R) |
861 | { | |
862 | bidi_it->paragraph_dir = L2R; | |
863 | bidi_it->new_paragraph = 0; | |
864 | } | |
865 | else if (dir == R2L) | |
866 | { | |
867 | bidi_it->paragraph_dir = R2L; | |
868 | bidi_it->new_paragraph = 0; | |
869 | } | |
b7b65b15 EZ |
870 | else if (dir == NEUTRAL_DIR) /* P2 */ |
871 | { | |
6bff6497 EZ |
872 | int ch, ch_len; |
873 | EMACS_INT pos; | |
874 | bidi_type_t type; | |
be39f003 EZ |
875 | EMACS_INT sep_len; |
876 | ||
877 | /* If we are inside a paragraph separator, we are just waiting | |
878 | for the separator to be exhausted; use the previous paragraph | |
e5a2fec7 EZ |
879 | direction. But don't do that if we have been just reseated, |
880 | because we need to reinitialize below in that case. */ | |
881 | if (!bidi_it->first_elt | |
882 | && bidi_it->charpos < bidi_it->separator_limit) | |
be39f003 EZ |
883 | return; |
884 | ||
b44d9321 EZ |
885 | /* If we are on a newline, get past it to where the next |
886 | paragraph might start. */ | |
c143c213 | 887 | pos = bidi_it->charpos; |
b44d9321 | 888 | if (FETCH_CHAR (bytepos) == '\n') |
be39f003 | 889 | { |
b44d9321 | 890 | bytepos++; |
c143c213 | 891 | pos++; |
be39f003 | 892 | } |
b44d9321 EZ |
893 | |
894 | /* We are either at the beginning of a paragraph or in the | |
895 | middle of it. Find where this paragraph starts. */ | |
896 | bytepos = bidi_find_paragraph_start (pos, bytepos); | |
6bff6497 EZ |
897 | |
898 | /* We should always be at the beginning of a new line at this | |
899 | point. */ | |
b44d9321 | 900 | if (!(bytepos == BEGV_BYTE || FETCH_CHAR (bytepos - 1) == '\n')) |
6bff6497 EZ |
901 | abort (); |
902 | ||
be39f003 EZ |
903 | bidi_it->separator_limit = -1; |
904 | bidi_it->new_paragraph = 0; | |
6bff6497 EZ |
905 | ch = FETCH_CHAR (bytepos); |
906 | ch_len = CHAR_BYTES (ch); | |
be39f003 | 907 | pos = BYTE_TO_CHAR (bytepos); |
6bff6497 | 908 | type = bidi_get_type (ch, NEUTRAL_DIR); |
b7b65b15 | 909 | |
e342a24d | 910 | for (pos++, bytepos += ch_len; |
b7b65b15 EZ |
911 | /* NOTE: UAX#9 says to search only for L, AL, or R types of |
912 | characters, and ignore RLE, RLO, LRE, and LRO. However, | |
913 | I'm not sure it makes sense to omit those 4; should try | |
914 | with and without that to see the effect. */ | |
915 | (bidi_get_category (type) != STRONG) | |
916 | || (bidi_ignore_explicit_marks_for_paragraph_level | |
917 | && (type == RLE || type == RLO | |
918 | || type == LRE || type == LRO)); | |
6bff6497 | 919 | type = bidi_get_type (ch, NEUTRAL_DIR)) |
b7b65b15 | 920 | { |
be39f003 | 921 | if (type == NEUTRAL_B && bidi_at_paragraph_end (pos, bytepos) >= -1) |
b7b65b15 EZ |
922 | break; |
923 | FETCH_CHAR_ADVANCE (ch, pos, bytepos); | |
924 | } | |
925 | if (type == STRONG_R || type == STRONG_AL) /* P3 */ | |
be39f003 EZ |
926 | bidi_it->paragraph_dir = R2L; |
927 | else if (type == STRONG_L) | |
928 | bidi_it->paragraph_dir = L2R; | |
b7b65b15 | 929 | } |
be39f003 EZ |
930 | else |
931 | abort (); | |
b7b65b15 | 932 | |
b44d9321 EZ |
933 | /* Contrary to UAX#9 clause P3, we only default the paragraph |
934 | direction to L2R if we have no previous usable paragraph | |
935 | direction. */ | |
be39f003 | 936 | if (bidi_it->paragraph_dir == NEUTRAL_DIR) |
b44d9321 | 937 | bidi_it->paragraph_dir = L2R; /* P3 and ``higher protocols'' */ |
be39f003 | 938 | if (bidi_it->paragraph_dir == R2L) |
b44d9321 | 939 | bidi_it->level_stack[0].level = 1; |
be39f003 | 940 | else |
b44d9321 | 941 | bidi_it->level_stack[0].level = 0; |
be39f003 EZ |
942 | |
943 | bidi_line_init (bidi_it); | |
b7b65b15 EZ |
944 | } |
945 | ||
6bff6497 EZ |
946 | /* Do whatever UAX#9 clause X8 says should be done at paragraph's |
947 | end. */ | |
b7b65b15 EZ |
948 | static inline void |
949 | bidi_set_paragraph_end (struct bidi_it *bidi_it) | |
950 | { | |
951 | bidi_it->invalid_levels = 0; | |
952 | bidi_it->invalid_rl_levels = -1; | |
953 | bidi_it->stack_idx = 0; | |
954 | bidi_it->resolved_level = bidi_it->level_stack[0].level; | |
b7b65b15 EZ |
955 | } |
956 | ||
89d3374a | 957 | /* Initialize the bidi iterator from buffer position CHARPOS. */ |
b7b65b15 | 958 | void |
6bff6497 | 959 | bidi_init_it (EMACS_INT charpos, EMACS_INT bytepos, struct bidi_it *bidi_it) |
b7b65b15 EZ |
960 | { |
961 | if (! bidi_initialized) | |
962 | bidi_initialize (); | |
89d3374a EZ |
963 | bidi_it->charpos = charpos; |
964 | bidi_it->bytepos = bytepos; | |
6bff6497 EZ |
965 | bidi_it->first_elt = 1; |
966 | bidi_set_paragraph_end (bidi_it); | |
967 | bidi_it->new_paragraph = 1; | |
be39f003 | 968 | bidi_it->separator_limit = -1; |
b44d9321 | 969 | bidi_it->paragraph_dir = NEUTRAL_DIR; |
b7b65b15 | 970 | bidi_it->type = NEUTRAL_B; |
89d3374a | 971 | bidi_it->type_after_w1 = UNKNOWN_BT; |
b7b65b15 | 972 | bidi_it->orig_type = UNKNOWN_BT; |
b7b65b15 | 973 | bidi_it->prev_was_pdf = 0; |
89d3374a EZ |
974 | bidi_it->prev.type = bidi_it->prev.type_after_w1 = UNKNOWN_BT; |
975 | bidi_it->last_strong.type = bidi_it->last_strong.type_after_w1 = | |
976 | bidi_it->last_strong.orig_type = UNKNOWN_BT; | |
b7b65b15 EZ |
977 | bidi_it->next_for_neutral.charpos = -1; |
978 | bidi_it->next_for_neutral.type = | |
89d3374a EZ |
979 | bidi_it->next_for_neutral.type_after_w1 = |
980 | bidi_it->next_for_neutral.orig_type = UNKNOWN_BT; | |
b7b65b15 EZ |
981 | bidi_it->prev_for_neutral.charpos = -1; |
982 | bidi_it->prev_for_neutral.type = | |
89d3374a EZ |
983 | bidi_it->prev_for_neutral.type_after_w1 = |
984 | bidi_it->prev_for_neutral.orig_type = UNKNOWN_BT; | |
b7b65b15 | 985 | bidi_it->sor = L2R; /* FIXME: should it be user-selectable? */ |
b7b65b15 EZ |
986 | } |
987 | ||
988 | /* Push the current embedding level and override status; reset the | |
989 | current level to LEVEL and the current override status to OVERRIDE. */ | |
990 | static inline void | |
991 | bidi_push_embedding_level (struct bidi_it *bidi_it, | |
992 | int level, bidi_dir_t override) | |
993 | { | |
994 | bidi_it->stack_idx++; | |
995 | if (bidi_it->stack_idx >= BIDI_MAXLEVEL) | |
996 | abort (); | |
997 | bidi_it->level_stack[bidi_it->stack_idx].level = level; | |
998 | bidi_it->level_stack[bidi_it->stack_idx].override = override; | |
999 | } | |
1000 | ||
1001 | /* Pop the embedding level and directional override status from the | |
1002 | stack, and return the new level. */ | |
1003 | static inline int | |
1004 | bidi_pop_embedding_level (struct bidi_it *bidi_it) | |
1005 | { | |
1006 | /* UAX#9 says to ignore invalid PDFs. */ | |
1007 | if (bidi_it->stack_idx > 0) | |
1008 | bidi_it->stack_idx--; | |
1009 | return bidi_it->level_stack[bidi_it->stack_idx].level; | |
1010 | } | |
1011 | ||
1012 | /* Record in SAVED_INFO the information about the current character. */ | |
1013 | static inline void | |
1014 | bidi_remember_char (struct bidi_saved_info *saved_info, | |
1015 | struct bidi_it *bidi_it) | |
1016 | { | |
1017 | saved_info->charpos = bidi_it->charpos; | |
1018 | saved_info->bytepos = bidi_it->bytepos; | |
1019 | saved_info->type = bidi_it->type; | |
2d6e4628 | 1020 | bidi_check_type (bidi_it->type); |
89d3374a EZ |
1021 | saved_info->type_after_w1 = bidi_it->type_after_w1; |
1022 | bidi_check_type (bidi_it->type_after_w1); | |
b7b65b15 | 1023 | saved_info->orig_type = bidi_it->orig_type; |
2d6e4628 | 1024 | bidi_check_type (bidi_it->orig_type); |
b7b65b15 EZ |
1025 | } |
1026 | ||
1027 | /* Resolve the type of a neutral character according to the type of | |
1028 | surrounding strong text and the current embedding level. */ | |
1029 | static inline bidi_type_t | |
1030 | bidi_resolve_neutral_1 (bidi_type_t prev_type, bidi_type_t next_type, int lev) | |
1031 | { | |
1032 | /* N1: European and Arabic numbers are treated as though they were R. */ | |
1033 | if (next_type == WEAK_EN || next_type == WEAK_AN) | |
1034 | next_type = STRONG_R; | |
1035 | if (prev_type == WEAK_EN || prev_type == WEAK_AN) | |
1036 | prev_type = STRONG_R; | |
1037 | ||
1038 | if (next_type == prev_type) /* N1 */ | |
1039 | return next_type; | |
1040 | else if ((lev & 1) == 0) /* N2 */ | |
1041 | return STRONG_L; | |
1042 | else | |
1043 | return STRONG_R; | |
1044 | } | |
1045 | ||
1046 | static inline int | |
1047 | bidi_explicit_dir_char (int c) | |
1048 | { | |
1049 | /* FIXME: this should be replaced with a lookup table with suitable | |
1050 | bits set, like standard C ctype macros do. */ | |
1051 | return (c == LRE_CHAR || c == LRO_CHAR | |
1052 | || c == RLE_CHAR || c == RLO_CHAR || c == PDF_CHAR); | |
1053 | } | |
1054 | ||
1055 | /* A helper function for bidi_resolve_explicit. It advances to the | |
1056 | next character in logical order and determines the new embedding | |
1057 | level and directional override, but does not take into account | |
1058 | empty embeddings. */ | |
1059 | static int | |
1060 | bidi_resolve_explicit_1 (struct bidi_it *bidi_it) | |
1061 | { | |
1062 | int curchar; | |
1063 | bidi_type_t type; | |
1064 | int current_level; | |
1065 | int new_level; | |
1066 | bidi_dir_t override; | |
1067 | ||
9c82e145 EZ |
1068 | if (bidi_it->bytepos < BEGV_BYTE /* after reseat to BEGV? */ |
1069 | || bidi_it->first_elt) | |
e7402cb2 | 1070 | { |
9c82e145 EZ |
1071 | bidi_it->first_elt = 0; |
1072 | if (bidi_it->charpos < BEGV) | |
1073 | bidi_it->charpos = BEGV; | |
1074 | bidi_it->bytepos = CHAR_TO_BYTE (bidi_it->charpos); | |
e7402cb2 | 1075 | } |
9c82e145 | 1076 | else if (bidi_it->bytepos < ZV_BYTE) /* don't move at ZV */ |
b7b65b15 EZ |
1077 | { |
1078 | bidi_it->charpos++; | |
e7402cb2 EZ |
1079 | if (bidi_it->ch_len == 0) |
1080 | abort (); | |
b7b65b15 EZ |
1081 | bidi_it->bytepos += bidi_it->ch_len; |
1082 | } | |
1083 | ||
1084 | current_level = bidi_it->level_stack[bidi_it->stack_idx].level; /* X1 */ | |
1085 | override = bidi_it->level_stack[bidi_it->stack_idx].override; | |
1086 | new_level = current_level; | |
1087 | ||
1088 | /* in case it is a unibyte character (not yet implemented) */ | |
1089 | /* _fetch_multibyte_char_len = 1; */ | |
e7402cb2 EZ |
1090 | if (bidi_it->bytepos >= ZV_BYTE) |
1091 | { | |
1092 | curchar = BIDI_EOB; | |
1093 | bidi_it->ch_len = 1; | |
1094 | } | |
1095 | else | |
1096 | { | |
1097 | curchar = FETCH_CHAR (bidi_it->bytepos); | |
1098 | bidi_it->ch_len = CHAR_BYTES (curchar); | |
1099 | } | |
b7b65b15 | 1100 | bidi_it->ch = curchar; |
b7b65b15 | 1101 | |
6bff6497 EZ |
1102 | /* Don't apply directional override here, as all the types we handle |
1103 | below will not be affected by the override anyway, and we need | |
1104 | the original type unaltered. The override will be applied in | |
1105 | bidi_resolve_weak. */ | |
1106 | type = bidi_get_type (curchar, NEUTRAL_DIR); | |
89d3374a EZ |
1107 | bidi_it->orig_type = type; |
1108 | bidi_check_type (bidi_it->orig_type); | |
b7b65b15 EZ |
1109 | |
1110 | if (type != PDF) | |
1111 | bidi_it->prev_was_pdf = 0; | |
1112 | ||
89d3374a | 1113 | bidi_it->type_after_w1 = UNKNOWN_BT; |
b7b65b15 EZ |
1114 | |
1115 | switch (type) | |
1116 | { | |
1117 | case RLE: /* X2 */ | |
1118 | case RLO: /* X4 */ | |
89d3374a EZ |
1119 | bidi_it->type_after_w1 = type; |
1120 | bidi_check_type (bidi_it->type_after_w1); | |
b7b65b15 EZ |
1121 | type = WEAK_BN; /* X9/Retaining */ |
1122 | if (bidi_it->ignore_bn_limit <= 0) | |
1123 | { | |
1124 | if (current_level <= BIDI_MAXLEVEL - 4) | |
1125 | { | |
1126 | /* Compute the least odd embedding level greater than | |
1127 | the current level. */ | |
1128 | new_level = ((current_level + 1) & ~1) + 1; | |
89d3374a | 1129 | if (bidi_it->type_after_w1 == RLE) |
b7b65b15 EZ |
1130 | override = NEUTRAL_DIR; |
1131 | else | |
1132 | override = R2L; | |
1133 | if (current_level == BIDI_MAXLEVEL - 4) | |
1134 | bidi_it->invalid_rl_levels = 0; | |
1135 | bidi_push_embedding_level (bidi_it, new_level, override); | |
1136 | } | |
1137 | else | |
1138 | { | |
1139 | bidi_it->invalid_levels++; | |
1140 | /* See the commentary about invalid_rl_levels below. */ | |
1141 | if (bidi_it->invalid_rl_levels < 0) | |
1142 | bidi_it->invalid_rl_levels = 0; | |
1143 | bidi_it->invalid_rl_levels++; | |
1144 | } | |
1145 | } | |
89d3374a | 1146 | else if (bidi_it->prev.type_after_w1 == WEAK_EN /* W5/Retaining */ |
b7b65b15 EZ |
1147 | || bidi_it->next_en_pos > bidi_it->charpos) |
1148 | type = WEAK_EN; | |
1149 | break; | |
1150 | case LRE: /* X3 */ | |
1151 | case LRO: /* X5 */ | |
89d3374a EZ |
1152 | bidi_it->type_after_w1 = type; |
1153 | bidi_check_type (bidi_it->type_after_w1); | |
b7b65b15 EZ |
1154 | type = WEAK_BN; /* X9/Retaining */ |
1155 | if (bidi_it->ignore_bn_limit <= 0) | |
1156 | { | |
1157 | if (current_level <= BIDI_MAXLEVEL - 5) | |
1158 | { | |
1159 | /* Compute the least even embedding level greater than | |
1160 | the current level. */ | |
1161 | new_level = ((current_level + 2) & ~1); | |
89d3374a | 1162 | if (bidi_it->type_after_w1 == LRE) |
b7b65b15 EZ |
1163 | override = NEUTRAL_DIR; |
1164 | else | |
1165 | override = L2R; | |
1166 | bidi_push_embedding_level (bidi_it, new_level, override); | |
1167 | } | |
1168 | else | |
1169 | { | |
1170 | bidi_it->invalid_levels++; | |
1171 | /* invalid_rl_levels counts invalid levels encountered | |
1172 | while the embedding level was already too high for | |
1173 | LRE/LRO, but not for RLE/RLO. That is because | |
1174 | there may be exactly one PDF which we should not | |
1175 | ignore even though invalid_levels is non-zero. | |
1176 | invalid_rl_levels helps to know what PDF is | |
1177 | that. */ | |
1178 | if (bidi_it->invalid_rl_levels >= 0) | |
1179 | bidi_it->invalid_rl_levels++; | |
1180 | } | |
1181 | } | |
89d3374a | 1182 | else if (bidi_it->prev.type_after_w1 == WEAK_EN /* W5/Retaining */ |
b7b65b15 EZ |
1183 | || bidi_it->next_en_pos > bidi_it->charpos) |
1184 | type = WEAK_EN; | |
1185 | break; | |
1186 | case PDF: /* X7 */ | |
89d3374a EZ |
1187 | bidi_it->type_after_w1 = type; |
1188 | bidi_check_type (bidi_it->type_after_w1); | |
b7b65b15 EZ |
1189 | type = WEAK_BN; /* X9/Retaining */ |
1190 | if (bidi_it->ignore_bn_limit <= 0) | |
1191 | { | |
1192 | if (!bidi_it->invalid_rl_levels) | |
1193 | { | |
1194 | new_level = bidi_pop_embedding_level (bidi_it); | |
1195 | bidi_it->invalid_rl_levels = -1; | |
1196 | if (bidi_it->invalid_levels) | |
1197 | bidi_it->invalid_levels--; | |
1198 | /* else nothing: UAX#9 says to ignore invalid PDFs */ | |
1199 | } | |
1200 | if (!bidi_it->invalid_levels) | |
1201 | new_level = bidi_pop_embedding_level (bidi_it); | |
1202 | else | |
1203 | { | |
1204 | bidi_it->invalid_levels--; | |
1205 | bidi_it->invalid_rl_levels--; | |
1206 | } | |
1207 | } | |
89d3374a | 1208 | else if (bidi_it->prev.type_after_w1 == WEAK_EN /* W5/Retaining */ |
b7b65b15 EZ |
1209 | || bidi_it->next_en_pos > bidi_it->charpos) |
1210 | type = WEAK_EN; | |
1211 | break; | |
1212 | default: | |
1213 | /* Nothing. */ | |
1214 | break; | |
1215 | } | |
1216 | ||
1217 | bidi_it->type = type; | |
2d6e4628 | 1218 | bidi_check_type (bidi_it->type); |
b7b65b15 EZ |
1219 | |
1220 | return new_level; | |
1221 | } | |
1222 | ||
1223 | /* Given an iterator state in BIDI_IT, advance one character position | |
1224 | in the buffer to the next character (in the logical order), resolve | |
1225 | any explicit embeddings and directional overrides, and return the | |
1226 | embedding level of the character after resolving explicit | |
1227 | directives and ignoring empty embeddings. */ | |
1228 | static int | |
1229 | bidi_resolve_explicit (struct bidi_it *bidi_it) | |
1230 | { | |
1231 | int prev_level = bidi_it->level_stack[bidi_it->stack_idx].level; | |
1232 | int new_level = bidi_resolve_explicit_1 (bidi_it); | |
1233 | ||
1234 | if (prev_level < new_level | |
1235 | && bidi_it->type == WEAK_BN | |
1236 | && bidi_it->ignore_bn_limit == 0 /* only if not already known */ | |
e7402cb2 | 1237 | && bidi_it->ch != BIDI_EOB /* not already at EOB */ |
b7b65b15 EZ |
1238 | && bidi_explicit_dir_char (FETCH_CHAR (bidi_it->bytepos |
1239 | + bidi_it->ch_len))) | |
1240 | { | |
1241 | /* Avoid pushing and popping embedding levels if the level run | |
1242 | is empty, as this breaks level runs where it shouldn't. | |
1243 | UAX#9 removes all the explicit embedding and override codes, | |
1244 | so empty embeddings disappear without a trace. We need to | |
1245 | behave as if we did the same. */ | |
1246 | struct bidi_it saved_it; | |
1247 | int level = prev_level; | |
1248 | ||
1249 | bidi_copy_it (&saved_it, bidi_it); | |
1250 | ||
1251 | while (bidi_explicit_dir_char (FETCH_CHAR (bidi_it->bytepos | |
1252 | + bidi_it->ch_len))) | |
1253 | { | |
1254 | level = bidi_resolve_explicit_1 (bidi_it); | |
1255 | } | |
1256 | ||
1257 | if (level == prev_level) /* empty embedding */ | |
1258 | saved_it.ignore_bn_limit = bidi_it->charpos + 1; | |
1259 | else /* this embedding is non-empty */ | |
1260 | saved_it.ignore_bn_limit = -1; | |
1261 | ||
1262 | bidi_copy_it (bidi_it, &saved_it); | |
1263 | if (bidi_it->ignore_bn_limit > 0) | |
1264 | { | |
1265 | /* We pushed a level, but we shouldn't have. Undo that. */ | |
1266 | if (!bidi_it->invalid_rl_levels) | |
1267 | { | |
1268 | new_level = bidi_pop_embedding_level (bidi_it); | |
1269 | bidi_it->invalid_rl_levels = -1; | |
1270 | if (bidi_it->invalid_levels) | |
1271 | bidi_it->invalid_levels--; | |
1272 | } | |
1273 | if (!bidi_it->invalid_levels) | |
1274 | new_level = bidi_pop_embedding_level (bidi_it); | |
1275 | else | |
1276 | { | |
1277 | bidi_it->invalid_levels--; | |
1278 | bidi_it->invalid_rl_levels--; | |
1279 | } | |
1280 | } | |
1281 | } | |
1282 | ||
b7b65b15 EZ |
1283 | if (bidi_it->type == NEUTRAL_B) /* X8 */ |
1284 | { | |
6bff6497 EZ |
1285 | /* End of buffer does _not_ indicate a new paragraph is coming. |
1286 | Otherwise, each character inserted at EOB will be processed | |
1287 | as starting a new paragraph. */ | |
1288 | if (bidi_it->bytepos < ZV_BYTE) | |
1289 | bidi_set_paragraph_end (bidi_it); | |
1290 | /* This is needed by bidi_resolve_weak below, and in L1. */ | |
1291 | bidi_it->type_after_w1 = bidi_it->type; | |
89d3374a | 1292 | bidi_check_type (bidi_it->type_after_w1); |
b7b65b15 EZ |
1293 | } |
1294 | ||
1295 | return new_level; | |
1296 | } | |
1297 | ||
1298 | /* Advance in the buffer, resolve weak types and return the type of | |
1299 | the next character after weak type resolution. */ | |
1300 | bidi_type_t | |
1301 | bidi_resolve_weak (struct bidi_it *bidi_it) | |
1302 | { | |
1303 | bidi_type_t type; | |
1304 | bidi_dir_t override; | |
1305 | int prev_level = bidi_it->level_stack[bidi_it->stack_idx].level; | |
1306 | int new_level = bidi_resolve_explicit (bidi_it); | |
1307 | int next_char; | |
1308 | bidi_type_t type_of_next; | |
1309 | struct bidi_it saved_it; | |
1310 | ||
1311 | type = bidi_it->type; | |
1312 | override = bidi_it->level_stack[bidi_it->stack_idx].override; | |
1313 | ||
1314 | if (type == UNKNOWN_BT | |
1315 | || type == LRE | |
1316 | || type == LRO | |
1317 | || type == RLE | |
1318 | || type == RLO | |
1319 | || type == PDF) | |
1320 | abort (); | |
1321 | ||
1322 | if (new_level != prev_level | |
1323 | || bidi_it->type == NEUTRAL_B) | |
1324 | { | |
1325 | /* We've got a new embedding level run, compute the directional | |
1326 | type of sor and initialize per-run variables (UAX#9, clause | |
1327 | X10). */ | |
1328 | bidi_set_sor_type (bidi_it, prev_level, new_level); | |
1329 | } | |
1330 | else if (type == NEUTRAL_S || type == NEUTRAL_WS | |
1331 | || type == WEAK_BN || type == STRONG_AL) | |
89d3374a EZ |
1332 | bidi_it->type_after_w1 = type; /* needed in L1 */ |
1333 | bidi_check_type (bidi_it->type_after_w1); | |
b7b65b15 EZ |
1334 | |
1335 | /* Level and directional override status are already recorded in | |
1336 | bidi_it, and do not need any change; see X6. */ | |
1337 | if (override == R2L) /* X6 */ | |
1338 | type = STRONG_R; | |
1339 | else if (override == L2R) | |
1340 | type = STRONG_L; | |
1341 | else if (type == STRONG_AL) | |
1342 | type = STRONG_R; /* W3 */ | |
1343 | else if (type == WEAK_NSM) /* W1 */ | |
1344 | { | |
1345 | /* Note that we don't need to consider the case where the prev | |
1346 | character has its type overridden by an RLO or LRO: such | |
1347 | characters are outside the current level run, and thus not | |
89d3374a EZ |
1348 | relevant to this NSM. Thus, NSM gets the orig_type of the |
1349 | previous character. */ | |
b7b65b15 | 1350 | if (bidi_it->prev.type != UNKNOWN_BT) |
89d3374a | 1351 | type = bidi_it->prev.orig_type; |
b7b65b15 EZ |
1352 | else if (bidi_it->sor == R2L) |
1353 | type = STRONG_R; | |
1354 | else if (bidi_it->sor == L2R) | |
1355 | type = STRONG_L; | |
1356 | else /* shouldn't happen! */ | |
1357 | abort (); | |
1358 | if (type == WEAK_EN /* W2 after W1 */ | |
89d3374a | 1359 | && bidi_it->last_strong.type_after_w1 == STRONG_AL) |
b7b65b15 EZ |
1360 | type = WEAK_AN; |
1361 | } | |
1362 | else if (type == WEAK_EN /* W2 */ | |
89d3374a | 1363 | && bidi_it->last_strong.type_after_w1 == STRONG_AL) |
b7b65b15 EZ |
1364 | type = WEAK_AN; |
1365 | else if ((type == WEAK_ES | |
89d3374a EZ |
1366 | && (bidi_it->prev.type_after_w1 == WEAK_EN /* W4 */ |
1367 | && (bidi_it->prev.orig_type == WEAK_EN | |
1368 | || bidi_it->prev.orig_type == WEAK_NSM))) /* aft W1 */ | |
b7b65b15 | 1369 | || (type == WEAK_CS |
89d3374a EZ |
1370 | && ((bidi_it->prev.type_after_w1 == WEAK_EN |
1371 | && (bidi_it->prev.orig_type == WEAK_EN /* W4 */ | |
1372 | || bidi_it->prev.orig_type == WEAK_NSM)) /* a/W1 */ | |
1373 | || bidi_it->prev.type_after_w1 == WEAK_AN))) /* W4 */ | |
b7b65b15 | 1374 | { |
e7402cb2 EZ |
1375 | next_char = |
1376 | bidi_it->bytepos + bidi_it->ch_len >= ZV_BYTE | |
1377 | ? BIDI_EOB : FETCH_CHAR (bidi_it->bytepos + bidi_it->ch_len); | |
6bff6497 | 1378 | type_of_next = bidi_get_type (next_char, override); |
b7b65b15 EZ |
1379 | |
1380 | if (type_of_next == WEAK_BN | |
1381 | || bidi_explicit_dir_char (next_char)) | |
1382 | { | |
1383 | bidi_copy_it (&saved_it, bidi_it); | |
1384 | while (bidi_resolve_explicit (bidi_it) == new_level | |
1385 | && bidi_it->type == WEAK_BN) | |
1386 | ; | |
1387 | type_of_next = bidi_it->type; | |
1388 | bidi_copy_it (bidi_it, &saved_it); | |
1389 | } | |
1390 | ||
1391 | /* If the next character is EN, but the last strong-type | |
1392 | character is AL, that next EN will be changed to AN when we | |
1393 | process it in W2 above. So in that case, this ES should not | |
1394 | be changed into EN. */ | |
1395 | if (type == WEAK_ES | |
1396 | && type_of_next == WEAK_EN | |
89d3374a | 1397 | && bidi_it->last_strong.type_after_w1 != STRONG_AL) |
b7b65b15 EZ |
1398 | type = WEAK_EN; |
1399 | else if (type == WEAK_CS) | |
1400 | { | |
89d3374a | 1401 | if (bidi_it->prev.type_after_w1 == WEAK_AN |
b7b65b15 EZ |
1402 | && (type_of_next == WEAK_AN |
1403 | /* If the next character is EN, but the last | |
1404 | strong-type character is AL, EN will be later | |
1405 | changed to AN when we process it in W2 above. So | |
1406 | in that case, this ES should not be changed into | |
1407 | EN. */ | |
1408 | || (type_of_next == WEAK_EN | |
89d3374a | 1409 | && bidi_it->last_strong.type_after_w1 == STRONG_AL))) |
b7b65b15 | 1410 | type = WEAK_AN; |
89d3374a | 1411 | else if (bidi_it->prev.type_after_w1 == WEAK_EN |
b7b65b15 | 1412 | && type_of_next == WEAK_EN |
89d3374a | 1413 | && bidi_it->last_strong.type_after_w1 != STRONG_AL) |
b7b65b15 EZ |
1414 | type = WEAK_EN; |
1415 | } | |
1416 | } | |
1417 | else if (type == WEAK_ET /* W5: ET with EN before or after it */ | |
1418 | || type == WEAK_BN) /* W5/Retaining */ | |
1419 | { | |
89d3374a | 1420 | if (bidi_it->prev.type_after_w1 == WEAK_EN /* ET/BN with EN before it */ |
b7b65b15 EZ |
1421 | || bidi_it->next_en_pos > bidi_it->charpos) |
1422 | type = WEAK_EN; | |
1423 | /* W5: ET with EN after it. */ | |
1424 | else | |
1425 | { | |
6bff6497 | 1426 | EMACS_INT en_pos = bidi_it->charpos + 1; |
b7b65b15 | 1427 | |
e7402cb2 EZ |
1428 | next_char = |
1429 | bidi_it->bytepos + bidi_it->ch_len >= ZV_BYTE | |
1430 | ? BIDI_EOB : FETCH_CHAR (bidi_it->bytepos + bidi_it->ch_len); | |
6bff6497 | 1431 | type_of_next = bidi_get_type (next_char, override); |
b7b65b15 EZ |
1432 | |
1433 | if (type_of_next == WEAK_ET | |
1434 | || type_of_next == WEAK_BN | |
1435 | || bidi_explicit_dir_char (next_char)) | |
1436 | { | |
1437 | bidi_copy_it (&saved_it, bidi_it); | |
1438 | while (bidi_resolve_explicit (bidi_it) == new_level | |
1439 | && (bidi_it->type == WEAK_BN || bidi_it->type == WEAK_ET)) | |
1440 | ; | |
1441 | type_of_next = bidi_it->type; | |
1442 | en_pos = bidi_it->charpos; | |
1443 | bidi_copy_it (bidi_it, &saved_it); | |
1444 | } | |
1445 | if (type_of_next == WEAK_EN) | |
1446 | { | |
1447 | /* If the last strong character is AL, the EN we've | |
1448 | found will become AN when we get to it (W2). */ | |
89d3374a | 1449 | if (bidi_it->last_strong.type_after_w1 != STRONG_AL) |
b7b65b15 EZ |
1450 | { |
1451 | type = WEAK_EN; | |
1452 | /* Remember this EN position, to speed up processing | |
1453 | of the next ETs. */ | |
1454 | bidi_it->next_en_pos = en_pos; | |
1455 | } | |
1456 | else if (type == WEAK_BN) | |
1457 | type = NEUTRAL_ON; /* W6/Retaining */ | |
1458 | } | |
1459 | } | |
1460 | } | |
1461 | ||
1462 | if (type == WEAK_ES || type == WEAK_ET || type == WEAK_CS /* W6 */ | |
89d3374a EZ |
1463 | || (type == WEAK_BN |
1464 | && (bidi_it->prev.type_after_w1 == WEAK_CS /* W6/Retaining */ | |
1465 | || bidi_it->prev.type_after_w1 == WEAK_ES | |
1466 | || bidi_it->prev.type_after_w1 == WEAK_ET))) | |
b7b65b15 EZ |
1467 | type = NEUTRAL_ON; |
1468 | ||
1469 | /* Store the type we've got so far, before we clobber it with strong | |
1470 | types in W7 and while resolving neutral types. But leave alone | |
1471 | the original types that were recorded above, because we will need | |
1472 | them for the L1 clause. */ | |
89d3374a EZ |
1473 | if (bidi_it->type_after_w1 == UNKNOWN_BT) |
1474 | bidi_it->type_after_w1 = type; | |
1475 | bidi_check_type (bidi_it->type_after_w1); | |
b7b65b15 EZ |
1476 | |
1477 | if (type == WEAK_EN) /* W7 */ | |
1478 | { | |
89d3374a | 1479 | if ((bidi_it->last_strong.type_after_w1 == STRONG_L) |
b7b65b15 EZ |
1480 | || (bidi_it->last_strong.type == UNKNOWN_BT && bidi_it->sor == L2R)) |
1481 | type = STRONG_L; | |
1482 | } | |
1483 | ||
1484 | bidi_it->type = type; | |
2d6e4628 | 1485 | bidi_check_type (bidi_it->type); |
b7b65b15 EZ |
1486 | return type; |
1487 | } | |
1488 | ||
1489 | bidi_type_t | |
1490 | bidi_resolve_neutral (struct bidi_it *bidi_it) | |
1491 | { | |
1492 | int prev_level = bidi_it->level_stack[bidi_it->stack_idx].level; | |
1493 | bidi_type_t type = bidi_resolve_weak (bidi_it); | |
1494 | int current_level = bidi_it->level_stack[bidi_it->stack_idx].level; | |
1495 | ||
1496 | if (!(type == STRONG_R | |
1497 | || type == STRONG_L | |
1498 | || type == WEAK_BN | |
1499 | || type == WEAK_EN | |
1500 | || type == WEAK_AN | |
1501 | || type == NEUTRAL_B | |
1502 | || type == NEUTRAL_S | |
1503 | || type == NEUTRAL_WS | |
1504 | || type == NEUTRAL_ON)) | |
1505 | abort (); | |
1506 | ||
1507 | if (bidi_get_category (type) == NEUTRAL | |
1508 | || (type == WEAK_BN && prev_level == current_level)) | |
1509 | { | |
1510 | if (bidi_it->next_for_neutral.type != UNKNOWN_BT) | |
1511 | type = bidi_resolve_neutral_1 (bidi_it->prev_for_neutral.type, | |
1512 | bidi_it->next_for_neutral.type, | |
1513 | current_level); | |
1514 | else | |
1515 | { | |
1516 | /* Arrrgh!! The UAX#9 algorithm is too deeply entrenched in | |
1517 | the assumption of batch-style processing; see clauses W4, | |
1518 | W5, and especially N1, which require to look far forward | |
1519 | (as well as back) in the buffer. May the fleas of a | |
1520 | thousand camels infest the armpits of those who design | |
1521 | supposedly general-purpose algorithms by looking at their | |
1522 | own implementations, and fail to consider other possible | |
1523 | implementations! */ | |
1524 | struct bidi_it saved_it; | |
1525 | bidi_type_t next_type; | |
1526 | ||
1527 | if (bidi_it->scan_dir == -1) | |
1528 | abort (); | |
1529 | ||
1530 | bidi_copy_it (&saved_it, bidi_it); | |
1531 | /* Scan the text forward until we find the first non-neutral | |
1532 | character, and then use that to resolve the neutral we | |
1533 | are dealing with now. We also cache the scanned iterator | |
1534 | states, to salvage some of the effort later. */ | |
1535 | bidi_cache_iterator_state (bidi_it, 0); | |
1536 | do { | |
1537 | /* Record the info about the previous character, so that | |
1538 | it will be cached below with this state. */ | |
89d3374a | 1539 | if (bidi_it->type_after_w1 != WEAK_BN /* W1/Retaining */ |
b7b65b15 EZ |
1540 | && bidi_it->type != WEAK_BN) |
1541 | bidi_remember_char (&bidi_it->prev, bidi_it); | |
1542 | type = bidi_resolve_weak (bidi_it); | |
1543 | /* Paragraph separators have their levels fully resolved | |
1544 | at this point, so cache them as resolved. */ | |
1545 | bidi_cache_iterator_state (bidi_it, type == NEUTRAL_B); | |
1546 | /* FIXME: implement L1 here, by testing for a newline and | |
1547 | resetting the level for any sequence of whitespace | |
1548 | characters adjacent to it. */ | |
1549 | } while (!(type == NEUTRAL_B | |
1550 | || (type != WEAK_BN | |
1551 | && bidi_get_category (type) != NEUTRAL) | |
1552 | /* This is all per level run, so stop when we | |
1553 | reach the end of this level run. */ | |
1554 | || bidi_it->level_stack[bidi_it->stack_idx].level != | |
1555 | current_level)); | |
1556 | ||
1557 | bidi_remember_char (&saved_it.next_for_neutral, bidi_it); | |
1558 | ||
1559 | switch (type) | |
1560 | { | |
1561 | case STRONG_L: | |
1562 | case STRONG_R: | |
1563 | case STRONG_AL: | |
1564 | next_type = type; | |
1565 | break; | |
1566 | case WEAK_EN: | |
1567 | case WEAK_AN: | |
1568 | /* N1: ``European and Arabic numbers are treated as | |
1569 | though they were R.'' */ | |
1570 | next_type = STRONG_R; | |
1571 | saved_it.next_for_neutral.type = STRONG_R; | |
1572 | break; | |
1573 | case WEAK_BN: | |
1574 | if (!bidi_explicit_dir_char (bidi_it->ch)) | |
1575 | abort (); /* can't happen: BNs are skipped */ | |
1576 | /* FALLTHROUGH */ | |
1577 | case NEUTRAL_B: | |
1578 | /* Marched all the way to the end of this level run. | |
1579 | We need to use the eor type, whose information is | |
1580 | stored by bidi_set_sor_type in the prev_for_neutral | |
1581 | member. */ | |
1582 | if (saved_it.type != WEAK_BN | |
89d3374a | 1583 | || bidi_get_category (bidi_it->prev.type_after_w1) == NEUTRAL) |
b7b65b15 EZ |
1584 | { |
1585 | next_type = bidi_it->prev_for_neutral.type; | |
1586 | saved_it.next_for_neutral.type = next_type; | |
2d6e4628 | 1587 | bidi_check_type (next_type); |
b7b65b15 EZ |
1588 | } |
1589 | else | |
1590 | { | |
1591 | /* This is a BN which does not adjoin neutrals. | |
1592 | Leave its type alone. */ | |
1593 | bidi_copy_it (bidi_it, &saved_it); | |
1594 | return bidi_it->type; | |
1595 | } | |
1596 | break; | |
1597 | default: | |
1598 | abort (); | |
1599 | } | |
1600 | type = bidi_resolve_neutral_1 (saved_it.prev_for_neutral.type, | |
1601 | next_type, current_level); | |
1602 | saved_it.type = type; | |
2d6e4628 | 1603 | bidi_check_type (type); |
b7b65b15 EZ |
1604 | bidi_copy_it (bidi_it, &saved_it); |
1605 | } | |
1606 | } | |
1607 | return type; | |
1608 | } | |
1609 | ||
1610 | /* Given an iterator state in BIDI_IT, advance one character position | |
1611 | in the buffer to the next character (in the logical order), resolve | |
1612 | the bidi type of that next character, and return that type. */ | |
1613 | bidi_type_t | |
1614 | bidi_type_of_next_char (struct bidi_it *bidi_it) | |
1615 | { | |
1616 | bidi_type_t type; | |
1617 | ||
1618 | /* This should always be called during a forward scan. */ | |
1619 | if (bidi_it->scan_dir != 1) | |
1620 | abort (); | |
1621 | ||
1622 | /* Reset the limit until which to ignore BNs if we step out of the | |
1623 | area where we found only empty levels. */ | |
1624 | if ((bidi_it->ignore_bn_limit > 0 | |
1625 | && bidi_it->ignore_bn_limit <= bidi_it->charpos) | |
1626 | || (bidi_it->ignore_bn_limit == -1 | |
1627 | && !bidi_explicit_dir_char (bidi_it->ch))) | |
1628 | bidi_it->ignore_bn_limit = 0; | |
1629 | ||
1630 | type = bidi_resolve_neutral (bidi_it); | |
1631 | ||
1632 | return type; | |
1633 | } | |
1634 | ||
1635 | /* Given an iterator state BIDI_IT, advance one character position in | |
1636 | the buffer to the next character (in the logical order), resolve | |
1637 | the embedding and implicit levels of that next character, and | |
1638 | return the resulting level. */ | |
1639 | int | |
1640 | bidi_level_of_next_char (struct bidi_it *bidi_it) | |
1641 | { | |
1642 | bidi_type_t type; | |
1643 | int level, prev_level = -1; | |
1644 | struct bidi_saved_info next_for_neutral; | |
1645 | ||
1646 | if (bidi_it->scan_dir == 1) | |
1647 | { | |
1648 | /* There's no sense in trying to advance if we hit end of text. */ | |
1649 | if (bidi_it->ch == BIDI_EOB) | |
1650 | return bidi_it->resolved_level; | |
1651 | ||
1652 | /* Record the info about the previous character. */ | |
89d3374a | 1653 | if (bidi_it->type_after_w1 != WEAK_BN /* W1/Retaining */ |
b7b65b15 EZ |
1654 | && bidi_it->type != WEAK_BN) |
1655 | bidi_remember_char (&bidi_it->prev, bidi_it); | |
89d3374a EZ |
1656 | if (bidi_it->type_after_w1 == STRONG_R |
1657 | || bidi_it->type_after_w1 == STRONG_L | |
1658 | || bidi_it->type_after_w1 == STRONG_AL) | |
b7b65b15 EZ |
1659 | bidi_remember_char (&bidi_it->last_strong, bidi_it); |
1660 | /* FIXME: it sounds like we don't need both prev and | |
1661 | prev_for_neutral members, but I'm leaving them both for now. */ | |
1662 | if (bidi_it->type == STRONG_R || bidi_it->type == STRONG_L | |
1663 | || bidi_it->type == WEAK_EN || bidi_it->type == WEAK_AN) | |
1664 | bidi_remember_char (&bidi_it->prev_for_neutral, bidi_it); | |
1665 | ||
1666 | /* If we overstepped the characters used for resolving neutrals | |
1667 | and whitespace, invalidate their info in the iterator. */ | |
1668 | if (bidi_it->charpos >= bidi_it->next_for_neutral.charpos) | |
1669 | bidi_it->next_for_neutral.type = UNKNOWN_BT; | |
1670 | if (bidi_it->next_en_pos >= 0 | |
1671 | && bidi_it->charpos >= bidi_it->next_en_pos) | |
1672 | bidi_it->next_en_pos = -1; | |
1673 | if (bidi_it->next_for_ws.type != UNKNOWN_BT | |
1674 | && bidi_it->charpos >= bidi_it->next_for_ws.charpos) | |
1675 | bidi_it->next_for_ws.type = UNKNOWN_BT; | |
1676 | ||
1677 | /* This must be taken before we fill the iterator with the info | |
1678 | about the next char. If we scan backwards, the iterator | |
1679 | state must be already cached, so there's no need to know the | |
1680 | embedding level of the previous character, since we will be | |
1681 | returning to our caller shortly. */ | |
1682 | prev_level = bidi_it->level_stack[bidi_it->stack_idx].level; | |
1683 | } | |
1684 | next_for_neutral = bidi_it->next_for_neutral; | |
1685 | ||
1686 | /* Perhaps it is already cached. */ | |
1687 | type = bidi_cache_find (bidi_it->charpos + bidi_it->scan_dir, -1, bidi_it); | |
1688 | if (type != UNKNOWN_BT) | |
1689 | { | |
1690 | /* Don't lose the information for resolving neutrals! The | |
1691 | cached states could have been cached before their | |
1692 | next_for_neutral member was computed. If we are on our way | |
1693 | forward, we can simply take the info from the previous | |
1694 | state. */ | |
1695 | if (bidi_it->scan_dir == 1 | |
1696 | && bidi_it->next_for_neutral.type == UNKNOWN_BT) | |
1697 | bidi_it->next_for_neutral = next_for_neutral; | |
1698 | ||
1699 | /* If resolved_level is -1, it means this state was cached | |
1700 | before it was completely resolved, so we cannot return | |
1701 | it. */ | |
1702 | if (bidi_it->resolved_level != -1) | |
1703 | return bidi_it->resolved_level; | |
1704 | } | |
1705 | if (bidi_it->scan_dir == -1) | |
1706 | /* If we are going backwards, the iterator state is already cached | |
1707 | from previous scans, and should be fully resolved. */ | |
1708 | abort (); | |
1709 | ||
1710 | if (type == UNKNOWN_BT) | |
1711 | type = bidi_type_of_next_char (bidi_it); | |
1712 | ||
1713 | if (type == NEUTRAL_B) | |
1714 | return bidi_it->resolved_level; | |
1715 | ||
1716 | level = bidi_it->level_stack[bidi_it->stack_idx].level; | |
1717 | if ((bidi_get_category (type) == NEUTRAL /* && type != NEUTRAL_B */) | |
1718 | || (type == WEAK_BN && prev_level == level)) | |
1719 | { | |
1720 | if (bidi_it->next_for_neutral.type == UNKNOWN_BT) | |
1721 | abort (); | |
1722 | ||
1723 | /* If the cached state shows a neutral character, it was not | |
1724 | resolved by bidi_resolve_neutral, so do it now. */ | |
1725 | type = bidi_resolve_neutral_1 (bidi_it->prev_for_neutral.type, | |
1726 | bidi_it->next_for_neutral.type, | |
1727 | level); | |
1728 | } | |
1729 | ||
1730 | if (!(type == STRONG_R | |
1731 | || type == STRONG_L | |
1732 | || type == WEAK_BN | |
1733 | || type == WEAK_EN | |
1734 | || type == WEAK_AN)) | |
1735 | abort (); | |
1736 | bidi_it->type = type; | |
2d6e4628 | 1737 | bidi_check_type (bidi_it->type); |
b7b65b15 EZ |
1738 | |
1739 | /* For L1 below, we need to know, for each WS character, whether | |
1740 | it belongs to a sequence of WS characters preceeding a newline | |
1741 | or a TAB or a paragraph separator. */ | |
89d3374a | 1742 | if (bidi_it->orig_type == NEUTRAL_WS |
b7b65b15 EZ |
1743 | && bidi_it->next_for_ws.type == UNKNOWN_BT) |
1744 | { | |
1745 | int ch; | |
1746 | int clen = bidi_it->ch_len; | |
6bff6497 EZ |
1747 | EMACS_INT bpos = bidi_it->bytepos; |
1748 | EMACS_INT cpos = bidi_it->charpos; | |
b7b65b15 EZ |
1749 | bidi_type_t chtype; |
1750 | ||
1751 | do { | |
1752 | /*_fetch_multibyte_char_len = 1;*/ | |
e7402cb2 | 1753 | ch = bpos + clen >= ZV_BYTE ? BIDI_EOB : FETCH_CHAR (bpos + clen); |
b7b65b15 EZ |
1754 | bpos += clen; |
1755 | cpos++; | |
e7402cb2 EZ |
1756 | clen = (ch == BIDI_EOB ? 1 : CHAR_BYTES (ch)); |
1757 | if (ch == '\n' || ch == BIDI_EOB /* || ch == LINESEP_CHAR */) | |
b7b65b15 EZ |
1758 | chtype = NEUTRAL_B; |
1759 | else | |
6bff6497 | 1760 | chtype = bidi_get_type (ch, NEUTRAL_DIR); |
b7b65b15 EZ |
1761 | } while (chtype == NEUTRAL_WS || chtype == WEAK_BN |
1762 | || bidi_explicit_dir_char (ch)); /* L1/Retaining */ | |
1763 | bidi_it->next_for_ws.type = chtype; | |
2d6e4628 | 1764 | bidi_check_type (bidi_it->next_for_ws.type); |
b7b65b15 EZ |
1765 | bidi_it->next_for_ws.charpos = cpos; |
1766 | bidi_it->next_for_ws.bytepos = bpos; | |
1767 | } | |
1768 | ||
1769 | /* Resolve implicit levels, with a twist: PDFs get the embedding | |
1770 | level of the enbedding they terminate. See below for the | |
1771 | reason. */ | |
89d3374a | 1772 | if (bidi_it->orig_type == PDF |
b7b65b15 EZ |
1773 | /* Don't do this if this formatting code didn't change the |
1774 | embedding level due to invalid or empty embeddings. */ | |
1775 | && prev_level != level) | |
1776 | { | |
1777 | /* Don't look in UAX#9 for the reason for this: it's our own | |
1778 | private quirk. The reason is that we want the formatting | |
1779 | codes to be delivered so that they bracket the text of their | |
1780 | embedding. For example, given the text | |
1781 | ||
1782 | {RLO}teST{PDF} | |
1783 | ||
1784 | we want it to be displayed as | |
1785 | ||
1786 | {RLO}STet{PDF} | |
1787 | ||
1788 | not as | |
1789 | ||
1790 | STet{RLO}{PDF} | |
1791 | ||
1792 | which will result because we bump up the embedding level as | |
1793 | soon as we see the RLO and pop it as soon as we see the PDF, | |
1794 | so RLO itself has the same embedding level as "teST", and | |
1795 | thus would be normally delivered last, just before the PDF. | |
1796 | The switch below fiddles with the level of PDF so that this | |
1797 | ugly side effect does not happen. | |
1798 | ||
1799 | (This is, of course, only important if the formatting codes | |
e7402cb2 EZ |
1800 | are actually displayed, but Emacs does need to display them |
1801 | if the user wants to.) */ | |
b7b65b15 EZ |
1802 | level = prev_level; |
1803 | } | |
89d3374a EZ |
1804 | else if (bidi_it->orig_type == NEUTRAL_B /* L1 */ |
1805 | || bidi_it->orig_type == NEUTRAL_S | |
e7402cb2 EZ |
1806 | || bidi_it->ch == '\n' || bidi_it->ch == BIDI_EOB |
1807 | /* || bidi_it->ch == LINESEP_CHAR */ | |
89d3374a | 1808 | || (bidi_it->orig_type == NEUTRAL_WS |
b7b65b15 EZ |
1809 | && (bidi_it->next_for_ws.type == NEUTRAL_B |
1810 | || bidi_it->next_for_ws.type == NEUTRAL_S))) | |
1811 | level = bidi_it->level_stack[0].level; | |
1812 | else if ((level & 1) == 0) /* I1 */ | |
1813 | { | |
1814 | if (type == STRONG_R) | |
1815 | level++; | |
1816 | else if (type == WEAK_EN || type == WEAK_AN) | |
1817 | level += 2; | |
1818 | } | |
1819 | else /* I2 */ | |
1820 | { | |
1821 | if (type == STRONG_L || type == WEAK_EN || type == WEAK_AN) | |
1822 | level++; | |
1823 | } | |
1824 | ||
1825 | bidi_it->resolved_level = level; | |
1826 | return level; | |
1827 | } | |
1828 | ||
1829 | /* Move to the other edge of a level given by LEVEL. If END_FLAG is | |
1830 | non-zero, we are at the end of a level, and we need to prepare to | |
1831 | resume the scan of the lower level. | |
1832 | ||
1833 | If this level's other edge is cached, we simply jump to it, filling | |
1834 | the iterator structure with the iterator state on the other edge. | |
1835 | Otherwise, we walk the buffer until we come back to the same level | |
1836 | as LEVEL. | |
1837 | ||
1838 | Note: we are not talking here about a ``level run'' in the UAX#9 | |
1839 | sense of the term, but rather about a ``level'' which includes | |
1840 | all the levels higher than it. In other words, given the levels | |
1841 | like this: | |
1842 | ||
1843 | 11111112222222333333334443343222222111111112223322111 | |
1844 | A B C | |
1845 | ||
1846 | and assuming we are at point A scanning left to right, this | |
1847 | function moves to point C, whereas the UAX#9 ``level 2 run'' ends | |
1848 | at point B. */ | |
1849 | static void | |
1850 | bidi_find_other_level_edge (struct bidi_it *bidi_it, int level, int end_flag) | |
1851 | { | |
1852 | int dir = end_flag ? -bidi_it->scan_dir : bidi_it->scan_dir; | |
1853 | int idx; | |
1854 | ||
1855 | /* Try the cache first. */ | |
1856 | if ((idx = bidi_cache_find_level_change (level, dir, end_flag)) >= 0) | |
1857 | bidi_cache_fetch_state (idx, bidi_it); | |
1858 | else | |
1859 | { | |
1860 | int new_level; | |
1861 | ||
1862 | if (end_flag) | |
1863 | abort (); /* if we are at end of level, its edges must be cached */ | |
1864 | ||
1865 | bidi_cache_iterator_state (bidi_it, 1); | |
1866 | do { | |
1867 | new_level = bidi_level_of_next_char (bidi_it); | |
1868 | bidi_cache_iterator_state (bidi_it, 1); | |
1869 | } while (new_level >= level); | |
1870 | } | |
1871 | } | |
1872 | ||
1873 | void | |
1874 | bidi_get_next_char_visually (struct bidi_it *bidi_it) | |
1875 | { | |
1876 | int old_level, new_level, next_level; | |
9c82e145 | 1877 | struct bidi_it sentinel; |
b7b65b15 EZ |
1878 | |
1879 | if (bidi_it->scan_dir == 0) | |
1880 | { | |
1881 | bidi_it->scan_dir = 1; /* default to logical order */ | |
1882 | } | |
1883 | ||
be39f003 EZ |
1884 | /* If we just passed a newline, initialize for the next line. */ |
1885 | if (!bidi_it->first_elt && bidi_it->orig_type == NEUTRAL_B) | |
1886 | bidi_line_init (bidi_it); | |
1887 | ||
9c82e145 | 1888 | /* Prepare the sentinel iterator state. */ |
b7b65b15 | 1889 | if (bidi_cache_idx == 0) |
9c82e145 EZ |
1890 | { |
1891 | bidi_copy_it (&sentinel, bidi_it); | |
1892 | if (bidi_it->first_elt) | |
1893 | { | |
1894 | sentinel.charpos--; /* cached charpos needs to be monotonic */ | |
1895 | sentinel.bytepos--; | |
1896 | sentinel.ch = '\n'; /* doesn't matter, but why not? */ | |
1897 | sentinel.ch_len = 1; | |
1898 | } | |
1899 | } | |
b7b65b15 EZ |
1900 | |
1901 | old_level = bidi_it->resolved_level; | |
1902 | new_level = bidi_level_of_next_char (bidi_it); | |
1903 | if (bidi_it->ch == BIDI_EOB) | |
1904 | return; | |
1905 | ||
1906 | /* Reordering of resolved levels (clause L2) is implemented by | |
1907 | jumping to the other edge of the level and flipping direction of | |
1908 | scanning the buffer whenever we find a level change. */ | |
1909 | if (new_level != old_level) | |
1910 | { | |
1911 | int ascending = new_level > old_level; | |
1912 | int level_to_search = ascending ? old_level + 1 : old_level; | |
1913 | int incr = ascending ? 1 : -1; | |
1914 | int expected_next_level = old_level + incr; | |
1915 | ||
1916 | /* If we don't have anything cached yet, we need to cache the | |
9c82e145 EZ |
1917 | sentinel state, since we'll need it to record where to jump |
1918 | when the last non-base level is exhausted. */ | |
b7b65b15 | 1919 | if (bidi_cache_idx == 0) |
9c82e145 | 1920 | bidi_cache_iterator_state (&sentinel, 1); |
b7b65b15 EZ |
1921 | /* Jump (or walk) to the other edge of this level. */ |
1922 | bidi_find_other_level_edge (bidi_it, level_to_search, !ascending); | |
1923 | /* Switch scan direction and peek at the next character in the | |
1924 | new direction. */ | |
1925 | bidi_it->scan_dir = -bidi_it->scan_dir; | |
1926 | ||
1927 | /* The following loop handles the case where the resolved level | |
1928 | jumps by more than one. This is typical for numbers inside a | |
1929 | run of text with left-to-right embedding direction, but can | |
1930 | also happen in other situations. In those cases the decision | |
1931 | where to continue after a level change, and in what direction, | |
1932 | is tricky. For example, given a text like below: | |
1933 | ||
1934 | abcdefgh | |
1935 | 11336622 | |
1936 | ||
1937 | (where the numbers below the text show the resolved levels), | |
1938 | the result of reordering according to UAX#9 should be this: | |
1939 | ||
1940 | efdcghba | |
1941 | ||
1942 | This is implemented by the loop below which flips direction | |
1943 | and jumps to the other edge of the level each time it finds | |
1944 | the new level not to be the expected one. The expected level | |
1945 | is always one more or one less than the previous one. */ | |
1946 | next_level = bidi_peek_at_next_level (bidi_it); | |
1947 | while (next_level != expected_next_level) | |
1948 | { | |
1949 | expected_next_level += incr; | |
1950 | level_to_search += incr; | |
1951 | bidi_find_other_level_edge (bidi_it, level_to_search, !ascending); | |
1952 | bidi_it->scan_dir = -bidi_it->scan_dir; | |
1953 | next_level = bidi_peek_at_next_level (bidi_it); | |
1954 | } | |
1955 | ||
1956 | /* Finally, deliver the next character in the new direction. */ | |
1957 | next_level = bidi_level_of_next_char (bidi_it); | |
1958 | } | |
1959 | ||
b44d9321 EZ |
1960 | /* Take note when we have just processed the newline that precedes |
1961 | the end of the paragraph. The next time we are about to be | |
1962 | called, set_iterator_to_next will automatically reinit the | |
1963 | paragraph direction, if needed. We do this at the newline before | |
1964 | the paragraph separator, because the next character might not be | |
1965 | the first character of the next paragraph, due to the bidi | |
1966 | reordering. */ | |
6bff6497 | 1967 | if (bidi_it->scan_dir == 1 |
be39f003 EZ |
1968 | && bidi_it->orig_type == NEUTRAL_B |
1969 | && bidi_it->bytepos < ZV_BYTE) | |
1970 | { | |
1971 | EMACS_INT sep_len = | |
1972 | bidi_at_paragraph_end (bidi_it->charpos + 1, | |
1973 | bidi_it->bytepos + bidi_it->ch_len); | |
1974 | if (sep_len >= 0) | |
1975 | { | |
1976 | bidi_it->new_paragraph = 1; | |
b44d9321 EZ |
1977 | /* Record the buffer position of the last character of the |
1978 | paragraph separator. */ | |
1979 | bidi_it->separator_limit = bidi_it->charpos + 1 + sep_len; | |
be39f003 EZ |
1980 | } |
1981 | } | |
6bff6497 | 1982 | |
b7b65b15 EZ |
1983 | if (bidi_it->scan_dir == 1 && bidi_cache_idx) |
1984 | { | |
1985 | /* If we are at paragraph's base embedding level and beyond the | |
1986 | last cached position, the cache's job is done and we can | |
1987 | discard it. */ | |
1988 | if (bidi_it->resolved_level == bidi_it->level_stack[0].level | |
1989 | && bidi_it->charpos > bidi_cache[bidi_cache_idx - 1].charpos) | |
1990 | bidi_cache_reset (); | |
1991 | /* But as long as we are caching during forward scan, we must | |
1992 | cache each state, or else the cache integrity will be | |
1993 | compromised: it assumes cached states correspond to buffer | |
1994 | positions 1:1. */ | |
1995 | else | |
1996 | bidi_cache_iterator_state (bidi_it, 1); | |
1997 | } | |
1998 | } | |
1999 | ||
2000 | /* This is meant to be called from within the debugger, whenever you | |
2001 | wish to examine the cache contents. */ | |
2002 | void | |
2003 | bidi_dump_cached_states (void) | |
2004 | { | |
2005 | int i; | |
2006 | int ndigits = 1; | |
2007 | ||
2008 | if (bidi_cache_idx == 0) | |
2009 | { | |
2010 | fprintf (stderr, "The cache is empty.\n"); | |
2011 | return; | |
2012 | } | |
2013 | fprintf (stderr, "Total of %d state%s in cache:\n", | |
2014 | bidi_cache_idx, bidi_cache_idx == 1 ? "" : "s"); | |
2015 | ||
2016 | for (i = bidi_cache[bidi_cache_idx - 1].charpos; i > 0; i /= 10) | |
2017 | ndigits++; | |
2018 | fputs ("ch ", stderr); | |
2019 | for (i = 0; i < bidi_cache_idx; i++) | |
2020 | fprintf (stderr, "%*c", ndigits, bidi_cache[i].ch); | |
2021 | fputs ("\n", stderr); | |
2022 | fputs ("lvl ", stderr); | |
2023 | for (i = 0; i < bidi_cache_idx; i++) | |
2024 | fprintf (stderr, "%*d", ndigits, bidi_cache[i].resolved_level); | |
2025 | fputs ("\n", stderr); | |
2026 | fputs ("pos ", stderr); | |
2027 | for (i = 0; i < bidi_cache_idx; i++) | |
2028 | fprintf (stderr, "%*d", ndigits, bidi_cache[i].charpos); | |
2029 | fputs ("\n", stderr); | |
2030 | } |