1 /* Low-level bidirectional buffer-scanning functions for GNU Emacs.
2 Copyright (C) 2000, 2001, 2004, 2005, 2009, 2010
3 Free Software Foundation, Inc.
5 This file is part of GNU Emacs.
7 GNU Emacs is free software: you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation, either version 3 of the License, or
10 (at your option) any later version.
12 GNU Emacs is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. */
20 /* Written by Eli Zaretskii <eliz@gnu.org>.
22 A sequential implementation of the Unicode Bidirectional algorithm,
23 as per UAX#9, a part of the Unicode Standard.
25 Unlike the reference and most other implementations, this one is
26 designed to be called once for every character in the buffer.
28 The main entry point is bidi_get_next_char_visually. Each time it
29 is called, it finds the next character in the visual order, and
30 returns its information in a special structure. The caller is then
31 expected to process this character for display or any other
32 purposes, and call bidi_get_next_char_visually for the next
33 character. See the comments in bidi_get_next_char_visually for
34 more details about its algorithm that finds the next visual-order
35 character by resolving their levels on the fly.
37 If you want to understand the code, you will have to read it
38 together with the relevant portions of UAX#9. The comments include
39 references to UAX#9 rules, for that very reason.
41 A note about references to UAX#9 rules: if the reference says
42 something like "X9/Retaining", it means that you need to refer to
43 rule X9 and to its modifications decribed in the "Implementation
44 Notes" section of UAX#9, under "Retaining Format Codes". */
60 #include "character.h"
61 #include "dispextern.h"
63 static int bidi_initialized
= 0;
65 static Lisp_Object bidi_type_table
;
67 /* FIXME: Remove these when bidi_explicit_dir_char uses a lookup table. */
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
77 #define BIDI_BOB -2 /* FIXME: Is this needed? */
79 /* Local data structures. (Look in dispextern.h for the rest.) */
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 */
89 /* Data type for describing the bidirectional character categories. */
97 int bidi_ignore_explicit_marks_for_paragraph_level
= 1;
99 static Lisp_Object fallback_paragraph_start_re
, fallback_paragraph_separate_re
;
100 static Lisp_Object Qparagraph_start
, Qparagraph_separate
;
105 /* FIXME: This should come from the Unicode Database. */
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
},
123 { 0x002B, 0x0000, WEAK_ES
},
124 { 0x002C, 0x0000, WEAK_CS
},
125 { 0x002D, 0x0000, WEAK_ES
},
126 { 0x002E, 0x002F, WEAK_CS
},
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
},
139 { 0x00AB, 0x00AC, NEUTRAL_ON
},
140 { 0x00AD, 0x0000, WEAK_BN
},
141 { 0x00AE, 0x00Af, NEUTRAL_ON
},
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
},
167 { 0x05C4, 0x05C5, WEAK_NSM
},
168 { 0x05C6, 0x0000, STRONG_R
},
169 { 0x05C7, 0x0000, WEAK_NSM
},
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
} };
388 bidi_type_table
= Fmake_char_table (Qnil
, make_number (STRONG_L
));
389 staticpro (&bidi_type_table
);
391 for (i
= 0; i
< sizeof bidi_type
/ sizeof bidi_type
[0]; i
++)
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
,
394 make_number (bidi_type
[i
].type
));
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
);
410 bidi_initialized
= 1;
413 /* Return the bidi type of a character CH, subject to the current
414 directional OVERRIDE. */
416 bidi_get_type (int ch
, bidi_dir_t override
)
418 bidi_type_t default_type
;
422 if (ch
< 0 || ch
> MAX_CHAR
)
425 default_type
= (bidi_type_t
) XINT (CHAR_TABLE_REF (bidi_type_table
, ch
));
427 if (override
== NEUTRAL_DIR
)
430 switch (default_type
)
432 /* Although UAX#9 does not tell, it doesn't make sense to
433 override NEUTRAL_B and LRM/RLM characters. */
448 if (override
== L2R
) /* X6 */
450 else if (override
== R2L
)
453 abort (); /* can't happen: handled above */
459 bidi_check_type (bidi_type_t type
)
461 if (type
< UNKNOWN_BT
|| type
> NEUTRAL_ON
)
465 /* Given a bidi TYPE of a character, return its category. */
467 bidi_get_category (bidi_type_t type
)
481 case PDF
: /* ??? really?? */
500 /* Return the mirrored character of C, if any.
502 Note: The conditions in UAX#9 clause L4 must be tested by the
504 /* FIXME: exceedingly temporary! Should consult the Unicode database
505 of character properties. */
507 bidi_mirror_char (int c
)
509 static const char mirrored_pairs
[] = "()<>[]{}";
510 const char *p
= c
> 0 && c
< 128 ? strchr (mirrored_pairs
, c
) : NULL
;
514 size_t i
= p
- mirrored_pairs
;
516 return mirrored_pairs
[(i
^ 1)];
521 /* Copy the bidi iterator from FROM to TO. To save cycles, this only
522 copies the part of the level stack that is actually in use. */
524 bidi_copy_it (struct bidi_it
*to
, struct bidi_it
*from
)
528 /* Copy everything except the level stack and beyond. */
529 memcpy (to
, from
, ((size_t)&((struct bidi_it
*)0)->level_stack
[0]));
531 /* Copy the active part of the level stack. */
532 to
->level_stack
[0] = from
->level_stack
[0]; /* level zero is always in use */
533 for (i
= 1; i
<= from
->stack_idx
; i
++)
534 to
->level_stack
[i
] = from
->level_stack
[i
];
537 /* Caching the bidi iterator states. */
539 static struct bidi_it bidi_cache
[1000]; /* FIXME: make this dynamically allocated! */
540 static int bidi_cache_idx
;
541 static int bidi_cache_last_idx
;
544 bidi_cache_reset (void)
547 bidi_cache_last_idx
= -1;
551 bidi_cache_fetch_state (int idx
, struct bidi_it
*bidi_it
)
553 int current_scan_dir
= bidi_it
->scan_dir
;
555 if (idx
< 0 || idx
>= bidi_cache_idx
)
558 bidi_copy_it (bidi_it
, &bidi_cache
[idx
]);
559 bidi_it
->scan_dir
= current_scan_dir
;
560 bidi_cache_last_idx
= idx
;
563 /* Find a cached state with a given CHARPOS and resolved embedding
564 level less or equal to LEVEL. if LEVEL is -1, disregard the
565 resolved levels in cached states. DIR, if non-zero, means search
566 in that direction from the last cache hit. */
568 bidi_cache_search (int charpos
, int level
, int dir
)
574 if (charpos
< bidi_cache
[bidi_cache_last_idx
].charpos
)
576 else if (charpos
> bidi_cache
[bidi_cache_last_idx
].charpos
)
579 i_start
= bidi_cache_last_idx
;
583 i_start
= bidi_cache_idx
- 1;
588 /* Linear search for now; FIXME! */
589 for (i
= i_start
; i
>= 0; i
--)
590 if (bidi_cache
[i
].charpos
== charpos
591 && (level
== -1 || bidi_cache
[i
].resolved_level
<= level
))
596 for (i
= i_start
; i
< bidi_cache_idx
; i
++)
597 if (bidi_cache
[i
].charpos
== charpos
598 && (level
== -1 || bidi_cache
[i
].resolved_level
<= level
))
606 /* Find a cached state where the resolved level changes to a value
607 that is lower than LEVEL, and return its cache slot index. DIR is
608 the direction to search, starting with the last used cache slot.
609 BEFORE, if non-zero, means return the index of the slot that is
610 ``before'' the level change in the search direction. That is,
611 given the cached levels like this:
616 and assuming we are at the position cached at the slot marked with
617 C, searching backwards (DIR = -1) for LEVEL = 2 will return the
618 index of slot B or A, depending whether BEFORE is, respectively,
621 bidi_cache_find_level_change (int level
, int dir
, int before
)
625 int i
= dir
? bidi_cache_last_idx
: bidi_cache_idx
- 1;
626 int incr
= before
? 1 : 0;
637 if (bidi_cache
[i
- incr
].resolved_level
>= 0
638 && bidi_cache
[i
- incr
].resolved_level
< level
)
645 while (i
< bidi_cache_idx
- incr
)
647 if (bidi_cache
[i
+ incr
].resolved_level
>= 0
648 && bidi_cache
[i
+ incr
].resolved_level
< level
)
659 bidi_cache_iterator_state (struct bidi_it
*bidi_it
, int resolved
)
663 /* We should never cache on backward scans. */
664 if (bidi_it
->scan_dir
== -1)
666 idx
= bidi_cache_search (bidi_it
->charpos
, -1, 1);
670 idx
= bidi_cache_idx
;
671 /* Don't overrun the cache limit. */
672 if (idx
> sizeof (bidi_cache
) / sizeof (bidi_cache
[0]) - 1)
674 /* Character positions should correspond to cache positions 1:1.
675 If we are outside the range of cached positions, the cache is
676 useless and must be reset. */
678 (bidi_it
->charpos
> bidi_cache
[idx
- 1].charpos
+ 1
679 || bidi_it
->charpos
< bidi_cache
[0].charpos
))
684 bidi_copy_it (&bidi_cache
[idx
], bidi_it
);
686 bidi_cache
[idx
].resolved_level
= -1;
687 bidi_cache
[idx
].new_paragraph
= 0;
691 /* Copy only the members which could have changed, to avoid
692 costly copying of the entire struct. */
693 bidi_cache
[idx
].type
= bidi_it
->type
;
694 bidi_check_type (bidi_it
->type
);
695 bidi_cache
[idx
].type_after_w1
= bidi_it
->type_after_w1
;
696 bidi_check_type (bidi_it
->type_after_w1
);
698 bidi_cache
[idx
].resolved_level
= bidi_it
->resolved_level
;
700 bidi_cache
[idx
].resolved_level
= -1;
701 bidi_cache
[idx
].invalid_levels
= bidi_it
->invalid_levels
;
702 bidi_cache
[idx
].invalid_rl_levels
= bidi_it
->invalid_rl_levels
;
703 bidi_cache
[idx
].next_for_neutral
= bidi_it
->next_for_neutral
;
704 bidi_cache
[idx
].next_for_ws
= bidi_it
->next_for_ws
;
705 bidi_cache
[idx
].ignore_bn_limit
= bidi_it
->ignore_bn_limit
;
708 bidi_cache_last_idx
= idx
;
709 if (idx
>= bidi_cache_idx
)
710 bidi_cache_idx
= idx
+ 1;
713 static inline bidi_type_t
714 bidi_cache_find (int charpos
, int level
, struct bidi_it
*bidi_it
)
716 int i
= bidi_cache_search (charpos
, level
, bidi_it
->scan_dir
);
720 bidi_dir_t current_scan_dir
= bidi_it
->scan_dir
;
722 bidi_copy_it (bidi_it
, &bidi_cache
[i
]);
723 bidi_cache_last_idx
= i
;
724 /* Don't let scan direction from from the cached state override
725 the current scan direction. */
726 bidi_it
->scan_dir
= current_scan_dir
;
727 return bidi_it
->type
;
734 bidi_peek_at_next_level (struct bidi_it
*bidi_it
)
736 if (bidi_cache_idx
== 0 || bidi_cache_last_idx
== -1)
738 return bidi_cache
[bidi_cache_last_idx
+ bidi_it
->scan_dir
].resolved_level
;
741 /* Check if buffer position CHARPOS/BYTEPOS is the end of a paragraph.
742 Value is the non-negative length of the paragraph separator
743 following the buffer position, -1 if position is at the beginning
744 of a new paragraph, or -2 if position is neither at beginning nor
745 at end of a paragraph. */
747 bidi_at_paragraph_end (EMACS_INT charpos
, EMACS_INT bytepos
)
749 Lisp_Object sep_re
= Fbuffer_local_value (Qparagraph_separate
,
751 Lisp_Object start_re
= Fbuffer_local_value (Qparagraph_start
,
755 if (!STRINGP (sep_re
))
756 sep_re
= fallback_paragraph_separate_re
;
757 if (!STRINGP (start_re
))
758 start_re
= fallback_paragraph_start_re
;
760 val
= fast_looking_at (sep_re
, charpos
, bytepos
, ZV
, ZV_BYTE
, Qnil
);
763 if (fast_looking_at (start_re
, charpos
, bytepos
, ZV
, ZV_BYTE
, Qnil
) >= 0)
772 /* Determine the start-of-run (sor) directional type given the two
773 embedding levels on either side of the run boundary. Also, update
774 the saved info about previously seen characters, since that info is
775 generally valid for a single level run. */
777 bidi_set_sor_type (struct bidi_it
*bidi_it
, int level_before
, int level_after
)
779 int higher_level
= level_before
> level_after
? level_before
: level_after
;
781 /* The prev_was_pdf gork is required for when we have several PDFs
782 in a row. In that case, we want to compute the sor type for the
783 next level run only once: when we see the first PDF. That's
784 because the sor type depends only on the higher of the two levels
785 that we find on the two sides of the level boundary (see UAX#9,
786 clause X10), and so we don't need to know the final embedding
787 level to which we descend after processing all the PDFs. */
788 if (!bidi_it
->prev_was_pdf
|| level_before
< level_after
)
789 /* FIXME: should the default sor direction be user selectable? */
790 bidi_it
->sor
= (higher_level
& 1) != 0 ? R2L
: L2R
;
791 if (level_before
> level_after
)
792 bidi_it
->prev_was_pdf
= 1;
794 bidi_it
->prev
.type
= UNKNOWN_BT
;
795 bidi_it
->last_strong
.type
= bidi_it
->last_strong
.type_after_w1
=
796 bidi_it
->last_strong
.orig_type
= UNKNOWN_BT
;
797 bidi_it
->prev_for_neutral
.type
= bidi_it
->sor
== R2L
? STRONG_R
: STRONG_L
;
798 bidi_it
->prev_for_neutral
.charpos
= bidi_it
->charpos
;
799 bidi_it
->prev_for_neutral
.bytepos
= bidi_it
->bytepos
;
800 bidi_it
->next_for_neutral
.type
= bidi_it
->next_for_neutral
.type_after_w1
=
801 bidi_it
->next_for_neutral
.orig_type
= UNKNOWN_BT
;
802 bidi_it
->ignore_bn_limit
= 0; /* meaning it's unknown */
806 bidi_line_init (struct bidi_it
*bidi_it
)
808 bidi_it
->scan_dir
= 1; /* FIXME: do we need to have control on this? */
809 bidi_it
->resolved_level
= bidi_it
->level_stack
[0].level
;
810 bidi_it
->level_stack
[0].override
= NEUTRAL_DIR
; /* X1 */
811 bidi_it
->invalid_levels
= 0;
812 bidi_it
->invalid_rl_levels
= -1;
813 bidi_it
->next_en_pos
= -1;
814 bidi_it
->next_for_ws
.type
= UNKNOWN_BT
;
815 bidi_set_sor_type (bidi_it
,
816 bidi_it
->paragraph_dir
== R2L
? 1 : 0,
817 bidi_it
->level_stack
[0].level
); /* X10 */
822 /* Find the beginning of this paragraph by looking back in the buffer.
823 Value is the byte position of the paragraph's beginning. */
825 bidi_find_paragraph_start (EMACS_INT pos
, EMACS_INT pos_byte
)
827 Lisp_Object re
= Fbuffer_local_value (Qparagraph_start
, Fcurrent_buffer ());
828 EMACS_INT limit
= ZV
, limit_byte
= ZV_BYTE
;
831 re
= fallback_paragraph_start_re
;
832 while (pos_byte
> BEGV_BYTE
833 && fast_looking_at (re
, pos
, pos_byte
, limit
, limit_byte
, Qnil
) < 0)
835 pos
= find_next_newline_no_quit (pos
- 1, -1);
836 pos_byte
= CHAR_TO_BYTE (pos
);
841 /* Determine the direction, a.k.a. base embedding level, of the
842 paragraph we are about to iterate through. If DIR is either L2R or
843 R2L, just use that. Otherwise, determine the paragraph direction
844 from the first strong character of the paragraph.
846 Note that this gives the paragraph separator the same direction as
847 the preceding paragraph, even though Emacs generally views the
848 separartor as not belonging to any paragraph. */
850 bidi_paragraph_init (bidi_dir_t dir
, struct bidi_it
*bidi_it
)
852 EMACS_INT bytepos
= bidi_it
->bytepos
;
854 /* Special case for an empty buffer. */
855 if (bytepos
== BEGV_BYTE
&& bytepos
== ZV_BYTE
)
857 /* We should never be called at EOB or before BEGV. */
858 else if (bytepos
>= ZV_BYTE
|| bytepos
< BEGV_BYTE
)
863 bidi_it
->paragraph_dir
= L2R
;
864 bidi_it
->new_paragraph
= 0;
868 bidi_it
->paragraph_dir
= R2L
;
869 bidi_it
->new_paragraph
= 0;
871 else if (dir
== NEUTRAL_DIR
) /* P2 */
878 /* If we are inside a paragraph separator, we are just waiting
879 for the separator to be exhausted; use the previous paragraph
880 direction. But don't do that if we have been just reseated,
881 because we need to reinitialize below in that case. */
882 if (!bidi_it
->first_elt
883 && bidi_it
->charpos
< bidi_it
->separator_limit
)
886 /* If we are on a newline, get past it to where the next
887 paragraph might start. But don't do that at BEGV since then
888 we are potentially in a new paragraph that doesn't yet
890 pos
= bidi_it
->charpos
;
891 if (bytepos
> BEGV_BYTE
&& FETCH_CHAR (bytepos
) == '\n')
897 /* We are either at the beginning of a paragraph or in the
898 middle of it. Find where this paragraph starts. */
899 bytepos
= bidi_find_paragraph_start (pos
, bytepos
);
901 /* We should always be at the beginning of a new line at this
903 if (!(bytepos
== BEGV_BYTE
|| FETCH_CHAR (bytepos
- 1) == '\n'))
906 bidi_it
->separator_limit
= -1;
907 bidi_it
->new_paragraph
= 0;
908 ch
= FETCH_CHAR (bytepos
);
909 ch_len
= CHAR_BYTES (ch
);
910 pos
= BYTE_TO_CHAR (bytepos
);
911 type
= bidi_get_type (ch
, NEUTRAL_DIR
);
913 for (pos
++, bytepos
+= ch_len
;
914 /* NOTE: UAX#9 says to search only for L, AL, or R types of
915 characters, and ignore RLE, RLO, LRE, and LRO. However,
916 I'm not sure it makes sense to omit those 4; should try
917 with and without that to see the effect. */
918 (bidi_get_category (type
) != STRONG
)
919 || (bidi_ignore_explicit_marks_for_paragraph_level
920 && (type
== RLE
|| type
== RLO
921 || type
== LRE
|| type
== LRO
));
922 type
= bidi_get_type (ch
, NEUTRAL_DIR
))
924 if (type
== NEUTRAL_B
&& bidi_at_paragraph_end (pos
, bytepos
) >= -1)
926 if (bytepos
>= ZV_BYTE
)
928 /* Pretend there's a paragraph separator at end of buffer. */
932 FETCH_CHAR_ADVANCE (ch
, pos
, bytepos
);
934 if (type
== STRONG_R
|| type
== STRONG_AL
) /* P3 */
935 bidi_it
->paragraph_dir
= R2L
;
936 else if (type
== STRONG_L
)
937 bidi_it
->paragraph_dir
= L2R
;
942 /* Contrary to UAX#9 clause P3, we only default the paragraph
943 direction to L2R if we have no previous usable paragraph
945 if (bidi_it
->paragraph_dir
== NEUTRAL_DIR
)
946 bidi_it
->paragraph_dir
= L2R
; /* P3 and ``higher protocols'' */
947 if (bidi_it
->paragraph_dir
== R2L
)
948 bidi_it
->level_stack
[0].level
= 1;
950 bidi_it
->level_stack
[0].level
= 0;
952 bidi_line_init (bidi_it
);
955 /* Do whatever UAX#9 clause X8 says should be done at paragraph's
958 bidi_set_paragraph_end (struct bidi_it
*bidi_it
)
960 bidi_it
->invalid_levels
= 0;
961 bidi_it
->invalid_rl_levels
= -1;
962 bidi_it
->stack_idx
= 0;
963 bidi_it
->resolved_level
= bidi_it
->level_stack
[0].level
;
966 /* Initialize the bidi iterator from buffer position CHARPOS. */
968 bidi_init_it (EMACS_INT charpos
, EMACS_INT bytepos
, struct bidi_it
*bidi_it
)
970 if (! bidi_initialized
)
972 bidi_it
->charpos
= charpos
;
973 bidi_it
->bytepos
= bytepos
;
974 bidi_it
->first_elt
= 1;
975 bidi_set_paragraph_end (bidi_it
);
976 bidi_it
->new_paragraph
= 1;
977 bidi_it
->separator_limit
= -1;
978 bidi_it
->type
= NEUTRAL_B
;
979 bidi_it
->type_after_w1
= UNKNOWN_BT
;
980 bidi_it
->orig_type
= UNKNOWN_BT
;
981 bidi_it
->prev_was_pdf
= 0;
982 bidi_it
->prev
.type
= bidi_it
->prev
.type_after_w1
= UNKNOWN_BT
;
983 bidi_it
->last_strong
.type
= bidi_it
->last_strong
.type_after_w1
=
984 bidi_it
->last_strong
.orig_type
= UNKNOWN_BT
;
985 bidi_it
->next_for_neutral
.charpos
= -1;
986 bidi_it
->next_for_neutral
.type
=
987 bidi_it
->next_for_neutral
.type_after_w1
=
988 bidi_it
->next_for_neutral
.orig_type
= UNKNOWN_BT
;
989 bidi_it
->prev_for_neutral
.charpos
= -1;
990 bidi_it
->prev_for_neutral
.type
=
991 bidi_it
->prev_for_neutral
.type_after_w1
=
992 bidi_it
->prev_for_neutral
.orig_type
= UNKNOWN_BT
;
993 bidi_it
->sor
= L2R
; /* FIXME: should it be user-selectable? */
996 /* Push the current embedding level and override status; reset the
997 current level to LEVEL and the current override status to OVERRIDE. */
999 bidi_push_embedding_level (struct bidi_it
*bidi_it
,
1000 int level
, bidi_dir_t override
)
1002 bidi_it
->stack_idx
++;
1003 if (bidi_it
->stack_idx
>= BIDI_MAXLEVEL
)
1005 bidi_it
->level_stack
[bidi_it
->stack_idx
].level
= level
;
1006 bidi_it
->level_stack
[bidi_it
->stack_idx
].override
= override
;
1009 /* Pop the embedding level and directional override status from the
1010 stack, and return the new level. */
1012 bidi_pop_embedding_level (struct bidi_it
*bidi_it
)
1014 /* UAX#9 says to ignore invalid PDFs. */
1015 if (bidi_it
->stack_idx
> 0)
1016 bidi_it
->stack_idx
--;
1017 return bidi_it
->level_stack
[bidi_it
->stack_idx
].level
;
1020 /* Record in SAVED_INFO the information about the current character. */
1022 bidi_remember_char (struct bidi_saved_info
*saved_info
,
1023 struct bidi_it
*bidi_it
)
1025 saved_info
->charpos
= bidi_it
->charpos
;
1026 saved_info
->bytepos
= bidi_it
->bytepos
;
1027 saved_info
->type
= bidi_it
->type
;
1028 bidi_check_type (bidi_it
->type
);
1029 saved_info
->type_after_w1
= bidi_it
->type_after_w1
;
1030 bidi_check_type (bidi_it
->type_after_w1
);
1031 saved_info
->orig_type
= bidi_it
->orig_type
;
1032 bidi_check_type (bidi_it
->orig_type
);
1035 /* Resolve the type of a neutral character according to the type of
1036 surrounding strong text and the current embedding level. */
1037 static inline bidi_type_t
1038 bidi_resolve_neutral_1 (bidi_type_t prev_type
, bidi_type_t next_type
, int lev
)
1040 /* N1: European and Arabic numbers are treated as though they were R. */
1041 if (next_type
== WEAK_EN
|| next_type
== WEAK_AN
)
1042 next_type
= STRONG_R
;
1043 if (prev_type
== WEAK_EN
|| prev_type
== WEAK_AN
)
1044 prev_type
= STRONG_R
;
1046 if (next_type
== prev_type
) /* N1 */
1048 else if ((lev
& 1) == 0) /* N2 */
1055 bidi_explicit_dir_char (int c
)
1057 /* FIXME: this should be replaced with a lookup table with suitable
1058 bits set, like standard C ctype macros do. */
1059 return (c
== LRE_CHAR
|| c
== LRO_CHAR
1060 || c
== RLE_CHAR
|| c
== RLO_CHAR
|| c
== PDF_CHAR
);
1063 /* A helper function for bidi_resolve_explicit. It advances to the
1064 next character in logical order and determines the new embedding
1065 level and directional override, but does not take into account
1066 empty embeddings. */
1068 bidi_resolve_explicit_1 (struct bidi_it
*bidi_it
)
1074 bidi_dir_t override
;
1076 if (bidi_it
->bytepos
< BEGV_BYTE
/* after reseat to BEGV? */
1077 || bidi_it
->first_elt
)
1079 bidi_it
->first_elt
= 0;
1080 if (bidi_it
->charpos
< BEGV
)
1081 bidi_it
->charpos
= BEGV
;
1082 bidi_it
->bytepos
= CHAR_TO_BYTE (bidi_it
->charpos
);
1084 else if (bidi_it
->bytepos
< ZV_BYTE
) /* don't move at ZV */
1087 if (bidi_it
->ch_len
== 0)
1089 bidi_it
->bytepos
+= bidi_it
->ch_len
;
1092 current_level
= bidi_it
->level_stack
[bidi_it
->stack_idx
].level
; /* X1 */
1093 override
= bidi_it
->level_stack
[bidi_it
->stack_idx
].override
;
1094 new_level
= current_level
;
1096 /* in case it is a unibyte character (not yet implemented) */
1097 /* _fetch_multibyte_char_len = 1; */
1098 if (bidi_it
->bytepos
>= ZV_BYTE
)
1101 bidi_it
->ch_len
= 1;
1105 curchar
= FETCH_CHAR (bidi_it
->bytepos
);
1106 bidi_it
->ch_len
= CHAR_BYTES (curchar
);
1108 bidi_it
->ch
= curchar
;
1110 /* Don't apply directional override here, as all the types we handle
1111 below will not be affected by the override anyway, and we need
1112 the original type unaltered. The override will be applied in
1113 bidi_resolve_weak. */
1114 type
= bidi_get_type (curchar
, NEUTRAL_DIR
);
1115 bidi_it
->orig_type
= type
;
1116 bidi_check_type (bidi_it
->orig_type
);
1119 bidi_it
->prev_was_pdf
= 0;
1121 bidi_it
->type_after_w1
= UNKNOWN_BT
;
1127 bidi_it
->type_after_w1
= type
;
1128 bidi_check_type (bidi_it
->type_after_w1
);
1129 type
= WEAK_BN
; /* X9/Retaining */
1130 if (bidi_it
->ignore_bn_limit
<= 0)
1132 if (current_level
<= BIDI_MAXLEVEL
- 4)
1134 /* Compute the least odd embedding level greater than
1135 the current level. */
1136 new_level
= ((current_level
+ 1) & ~1) + 1;
1137 if (bidi_it
->type_after_w1
== RLE
)
1138 override
= NEUTRAL_DIR
;
1141 if (current_level
== BIDI_MAXLEVEL
- 4)
1142 bidi_it
->invalid_rl_levels
= 0;
1143 bidi_push_embedding_level (bidi_it
, new_level
, override
);
1147 bidi_it
->invalid_levels
++;
1148 /* See the commentary about invalid_rl_levels below. */
1149 if (bidi_it
->invalid_rl_levels
< 0)
1150 bidi_it
->invalid_rl_levels
= 0;
1151 bidi_it
->invalid_rl_levels
++;
1154 else if (bidi_it
->prev
.type_after_w1
== WEAK_EN
/* W5/Retaining */
1155 || bidi_it
->next_en_pos
> bidi_it
->charpos
)
1160 bidi_it
->type_after_w1
= type
;
1161 bidi_check_type (bidi_it
->type_after_w1
);
1162 type
= WEAK_BN
; /* X9/Retaining */
1163 if (bidi_it
->ignore_bn_limit
<= 0)
1165 if (current_level
<= BIDI_MAXLEVEL
- 5)
1167 /* Compute the least even embedding level greater than
1168 the current level. */
1169 new_level
= ((current_level
+ 2) & ~1);
1170 if (bidi_it
->type_after_w1
== LRE
)
1171 override
= NEUTRAL_DIR
;
1174 bidi_push_embedding_level (bidi_it
, new_level
, override
);
1178 bidi_it
->invalid_levels
++;
1179 /* invalid_rl_levels counts invalid levels encountered
1180 while the embedding level was already too high for
1181 LRE/LRO, but not for RLE/RLO. That is because
1182 there may be exactly one PDF which we should not
1183 ignore even though invalid_levels is non-zero.
1184 invalid_rl_levels helps to know what PDF is
1186 if (bidi_it
->invalid_rl_levels
>= 0)
1187 bidi_it
->invalid_rl_levels
++;
1190 else if (bidi_it
->prev
.type_after_w1
== WEAK_EN
/* W5/Retaining */
1191 || bidi_it
->next_en_pos
> bidi_it
->charpos
)
1195 bidi_it
->type_after_w1
= type
;
1196 bidi_check_type (bidi_it
->type_after_w1
);
1197 type
= WEAK_BN
; /* X9/Retaining */
1198 if (bidi_it
->ignore_bn_limit
<= 0)
1200 if (!bidi_it
->invalid_rl_levels
)
1202 new_level
= bidi_pop_embedding_level (bidi_it
);
1203 bidi_it
->invalid_rl_levels
= -1;
1204 if (bidi_it
->invalid_levels
)
1205 bidi_it
->invalid_levels
--;
1206 /* else nothing: UAX#9 says to ignore invalid PDFs */
1208 if (!bidi_it
->invalid_levels
)
1209 new_level
= bidi_pop_embedding_level (bidi_it
);
1212 bidi_it
->invalid_levels
--;
1213 bidi_it
->invalid_rl_levels
--;
1216 else if (bidi_it
->prev
.type_after_w1
== WEAK_EN
/* W5/Retaining */
1217 || bidi_it
->next_en_pos
> bidi_it
->charpos
)
1225 bidi_it
->type
= type
;
1226 bidi_check_type (bidi_it
->type
);
1231 /* Given an iterator state in BIDI_IT, advance one character position
1232 in the buffer to the next character (in the logical order), resolve
1233 any explicit embeddings and directional overrides, and return the
1234 embedding level of the character after resolving explicit
1235 directives and ignoring empty embeddings. */
1237 bidi_resolve_explicit (struct bidi_it
*bidi_it
)
1239 int prev_level
= bidi_it
->level_stack
[bidi_it
->stack_idx
].level
;
1240 int new_level
= bidi_resolve_explicit_1 (bidi_it
);
1242 if (prev_level
< new_level
1243 && bidi_it
->type
== WEAK_BN
1244 && bidi_it
->ignore_bn_limit
== 0 /* only if not already known */
1245 && bidi_it
->ch
!= BIDI_EOB
/* not already at EOB */
1246 && bidi_explicit_dir_char (FETCH_CHAR (bidi_it
->bytepos
1247 + bidi_it
->ch_len
)))
1249 /* Avoid pushing and popping embedding levels if the level run
1250 is empty, as this breaks level runs where it shouldn't.
1251 UAX#9 removes all the explicit embedding and override codes,
1252 so empty embeddings disappear without a trace. We need to
1253 behave as if we did the same. */
1254 struct bidi_it saved_it
;
1255 int level
= prev_level
;
1257 bidi_copy_it (&saved_it
, bidi_it
);
1259 while (bidi_explicit_dir_char (FETCH_CHAR (bidi_it
->bytepos
1260 + bidi_it
->ch_len
)))
1262 level
= bidi_resolve_explicit_1 (bidi_it
);
1265 if (level
== prev_level
) /* empty embedding */
1266 saved_it
.ignore_bn_limit
= bidi_it
->charpos
+ 1;
1267 else /* this embedding is non-empty */
1268 saved_it
.ignore_bn_limit
= -1;
1270 bidi_copy_it (bidi_it
, &saved_it
);
1271 if (bidi_it
->ignore_bn_limit
> 0)
1273 /* We pushed a level, but we shouldn't have. Undo that. */
1274 if (!bidi_it
->invalid_rl_levels
)
1276 new_level
= bidi_pop_embedding_level (bidi_it
);
1277 bidi_it
->invalid_rl_levels
= -1;
1278 if (bidi_it
->invalid_levels
)
1279 bidi_it
->invalid_levels
--;
1281 if (!bidi_it
->invalid_levels
)
1282 new_level
= bidi_pop_embedding_level (bidi_it
);
1285 bidi_it
->invalid_levels
--;
1286 bidi_it
->invalid_rl_levels
--;
1291 if (bidi_it
->type
== NEUTRAL_B
) /* X8 */
1293 bidi_set_paragraph_end (bidi_it
);
1294 /* This is needed by bidi_resolve_weak below, and in L1. */
1295 bidi_it
->type_after_w1
= bidi_it
->type
;
1296 bidi_check_type (bidi_it
->type_after_w1
);
1302 /* Advance in the buffer, resolve weak types and return the type of
1303 the next character after weak type resolution. */
1305 bidi_resolve_weak (struct bidi_it
*bidi_it
)
1308 bidi_dir_t override
;
1309 int prev_level
= bidi_it
->level_stack
[bidi_it
->stack_idx
].level
;
1310 int new_level
= bidi_resolve_explicit (bidi_it
);
1312 bidi_type_t type_of_next
;
1313 struct bidi_it saved_it
;
1315 type
= bidi_it
->type
;
1316 override
= bidi_it
->level_stack
[bidi_it
->stack_idx
].override
;
1318 if (type
== UNKNOWN_BT
1326 if (new_level
!= prev_level
1327 || bidi_it
->type
== NEUTRAL_B
)
1329 /* We've got a new embedding level run, compute the directional
1330 type of sor and initialize per-run variables (UAX#9, clause
1332 bidi_set_sor_type (bidi_it
, prev_level
, new_level
);
1334 else if (type
== NEUTRAL_S
|| type
== NEUTRAL_WS
1335 || type
== WEAK_BN
|| type
== STRONG_AL
)
1336 bidi_it
->type_after_w1
= type
; /* needed in L1 */
1337 bidi_check_type (bidi_it
->type_after_w1
);
1339 /* Level and directional override status are already recorded in
1340 bidi_it, and do not need any change; see X6. */
1341 if (override
== R2L
) /* X6 */
1343 else if (override
== L2R
)
1347 if (type
== WEAK_NSM
) /* W1 */
1349 /* Note that we don't need to consider the case where the
1350 prev character has its type overridden by an RLO or LRO:
1351 such characters are outside the current level run, and
1352 thus not relevant to this NSM. Thus, NSM gets the
1353 orig_type of the previous character. */
1354 if (bidi_it
->prev
.type
!= UNKNOWN_BT
)
1355 type
= bidi_it
->prev
.orig_type
;
1356 else if (bidi_it
->sor
== R2L
)
1358 else if (bidi_it
->sor
== L2R
)
1360 else /* shouldn't happen! */
1363 if (type
== WEAK_EN
/* W2 */
1364 && bidi_it
->last_strong
.type_after_w1
== STRONG_AL
)
1366 else if (type
== STRONG_AL
) /* W3 */
1368 else if ((type
== WEAK_ES
/* W4 */
1369 && bidi_it
->prev
.type_after_w1
== WEAK_EN
1370 && bidi_it
->prev
.orig_type
== WEAK_EN
)
1372 && ((bidi_it
->prev
.type_after_w1
== WEAK_EN
1373 && bidi_it
->prev
.orig_type
== WEAK_EN
)
1374 || bidi_it
->prev
.type_after_w1
== WEAK_AN
)))
1377 bidi_it
->bytepos
+ bidi_it
->ch_len
>= ZV_BYTE
1378 ? BIDI_EOB
: FETCH_CHAR (bidi_it
->bytepos
+ bidi_it
->ch_len
);
1379 type_of_next
= bidi_get_type (next_char
, override
);
1381 if (type_of_next
== WEAK_BN
1382 || bidi_explicit_dir_char (next_char
))
1384 bidi_copy_it (&saved_it
, bidi_it
);
1385 while (bidi_resolve_explicit (bidi_it
) == new_level
1386 && bidi_it
->type
== WEAK_BN
)
1388 type_of_next
= bidi_it
->type
;
1389 bidi_copy_it (bidi_it
, &saved_it
);
1392 /* If the next character is EN, but the last strong-type
1393 character is AL, that next EN will be changed to AN when
1394 we process it in W2 above. So in that case, this ES
1395 should not be changed into EN. */
1397 && type_of_next
== WEAK_EN
1398 && bidi_it
->last_strong
.type_after_w1
!= STRONG_AL
)
1400 else if (type
== WEAK_CS
)
1402 if (bidi_it
->prev
.type_after_w1
== WEAK_AN
1403 && (type_of_next
== WEAK_AN
1404 /* If the next character is EN, but the last
1405 strong-type character is AL, EN will be later
1406 changed to AN when we process it in W2 above.
1407 So in that case, this ES should not be
1409 || (type_of_next
== WEAK_EN
1410 && bidi_it
->last_strong
.type_after_w1
== STRONG_AL
)))
1412 else if (bidi_it
->prev
.type_after_w1
== WEAK_EN
1413 && type_of_next
== WEAK_EN
1414 && bidi_it
->last_strong
.type_after_w1
!= STRONG_AL
)
1418 else if (type
== WEAK_ET
/* W5: ET with EN before or after it */
1419 || type
== WEAK_BN
) /* W5/Retaining */
1421 if (bidi_it
->prev
.type_after_w1
== WEAK_EN
/* ET/BN w/EN before it */
1422 || bidi_it
->next_en_pos
> bidi_it
->charpos
)
1424 else /* W5: ET/BN with EN after it. */
1426 EMACS_INT en_pos
= bidi_it
->charpos
+ 1;
1429 bidi_it
->bytepos
+ bidi_it
->ch_len
>= ZV_BYTE
1430 ? BIDI_EOB
: FETCH_CHAR (bidi_it
->bytepos
+ bidi_it
->ch_len
);
1431 type_of_next
= bidi_get_type (next_char
, override
);
1433 if (type_of_next
== WEAK_ET
1434 || type_of_next
== WEAK_BN
1435 || bidi_explicit_dir_char (next_char
))
1437 bidi_copy_it (&saved_it
, bidi_it
);
1438 while (bidi_resolve_explicit (bidi_it
) == new_level
1439 && (bidi_it
->type
== WEAK_BN
1440 || bidi_it
->type
== WEAK_ET
))
1442 type_of_next
= bidi_it
->type
;
1443 en_pos
= bidi_it
->charpos
;
1444 bidi_copy_it (bidi_it
, &saved_it
);
1446 if (type_of_next
== WEAK_EN
)
1448 /* If the last strong character is AL, the EN we've
1449 found will become AN when we get to it (W2). */
1450 if (bidi_it
->last_strong
.type_after_w1
!= STRONG_AL
)
1453 /* Remember this EN position, to speed up processing
1455 bidi_it
->next_en_pos
= en_pos
;
1457 else if (type
== WEAK_BN
)
1458 type
= NEUTRAL_ON
; /* W6/Retaining */
1464 if (type
== WEAK_ES
|| type
== WEAK_ET
|| type
== WEAK_CS
/* W6 */
1466 && (bidi_it
->prev
.type_after_w1
== WEAK_CS
/* W6/Retaining */
1467 || bidi_it
->prev
.type_after_w1
== WEAK_ES
1468 || bidi_it
->prev
.type_after_w1
== WEAK_ET
)))
1471 /* Store the type we've got so far, before we clobber it with strong
1472 types in W7 and while resolving neutral types. But leave alone
1473 the original types that were recorded above, because we will need
1474 them for the L1 clause. */
1475 if (bidi_it
->type_after_w1
== UNKNOWN_BT
)
1476 bidi_it
->type_after_w1
= type
;
1477 bidi_check_type (bidi_it
->type_after_w1
);
1479 if (type
== WEAK_EN
) /* W7 */
1481 if ((bidi_it
->last_strong
.type_after_w1
== STRONG_L
)
1482 || (bidi_it
->last_strong
.type
== UNKNOWN_BT
&& bidi_it
->sor
== L2R
))
1486 bidi_it
->type
= type
;
1487 bidi_check_type (bidi_it
->type
);
1492 bidi_resolve_neutral (struct bidi_it
*bidi_it
)
1494 int prev_level
= bidi_it
->level_stack
[bidi_it
->stack_idx
].level
;
1495 bidi_type_t type
= bidi_resolve_weak (bidi_it
);
1496 int current_level
= bidi_it
->level_stack
[bidi_it
->stack_idx
].level
;
1498 if (!(type
== STRONG_R
1503 || type
== NEUTRAL_B
1504 || type
== NEUTRAL_S
1505 || type
== NEUTRAL_WS
1506 || type
== NEUTRAL_ON
))
1509 if (bidi_get_category (type
) == NEUTRAL
1510 || (type
== WEAK_BN
&& prev_level
== current_level
))
1512 if (bidi_it
->next_for_neutral
.type
!= UNKNOWN_BT
)
1513 type
= bidi_resolve_neutral_1 (bidi_it
->prev_for_neutral
.type
,
1514 bidi_it
->next_for_neutral
.type
,
1518 /* Arrrgh!! The UAX#9 algorithm is too deeply entrenched in
1519 the assumption of batch-style processing; see clauses W4,
1520 W5, and especially N1, which require to look far forward
1521 (as well as back) in the buffer. May the fleas of a
1522 thousand camels infest the armpits of those who design
1523 supposedly general-purpose algorithms by looking at their
1524 own implementations, and fail to consider other possible
1526 struct bidi_it saved_it
;
1527 bidi_type_t next_type
;
1529 if (bidi_it
->scan_dir
== -1)
1532 bidi_copy_it (&saved_it
, bidi_it
);
1533 /* Scan the text forward until we find the first non-neutral
1534 character, and then use that to resolve the neutral we
1535 are dealing with now. We also cache the scanned iterator
1536 states, to salvage some of the effort later. */
1537 bidi_cache_iterator_state (bidi_it
, 0);
1539 /* Record the info about the previous character, so that
1540 it will be cached below with this state. */
1541 if (bidi_it
->type_after_w1
!= WEAK_BN
/* W1/Retaining */
1542 && bidi_it
->type
!= WEAK_BN
)
1543 bidi_remember_char (&bidi_it
->prev
, bidi_it
);
1544 type
= bidi_resolve_weak (bidi_it
);
1545 /* Paragraph separators have their levels fully resolved
1546 at this point, so cache them as resolved. */
1547 bidi_cache_iterator_state (bidi_it
, type
== NEUTRAL_B
);
1548 /* FIXME: implement L1 here, by testing for a newline and
1549 resetting the level for any sequence of whitespace
1550 characters adjacent to it. */
1551 } while (!(type
== NEUTRAL_B
1553 && bidi_get_category (type
) != NEUTRAL
)
1554 /* This is all per level run, so stop when we
1555 reach the end of this level run. */
1556 || bidi_it
->level_stack
[bidi_it
->stack_idx
].level
!=
1559 bidi_remember_char (&saved_it
.next_for_neutral
, bidi_it
);
1570 /* N1: ``European and Arabic numbers are treated as
1571 though they were R.'' */
1572 next_type
= STRONG_R
;
1573 saved_it
.next_for_neutral
.type
= STRONG_R
;
1576 if (!bidi_explicit_dir_char (bidi_it
->ch
))
1577 abort (); /* can't happen: BNs are skipped */
1580 /* Marched all the way to the end of this level run.
1581 We need to use the eor type, whose information is
1582 stored by bidi_set_sor_type in the prev_for_neutral
1584 if (saved_it
.type
!= WEAK_BN
1585 || bidi_get_category (bidi_it
->prev
.type_after_w1
) == NEUTRAL
)
1587 next_type
= bidi_it
->prev_for_neutral
.type
;
1588 saved_it
.next_for_neutral
.type
= next_type
;
1589 bidi_check_type (next_type
);
1593 /* This is a BN which does not adjoin neutrals.
1594 Leave its type alone. */
1595 bidi_copy_it (bidi_it
, &saved_it
);
1596 return bidi_it
->type
;
1602 type
= bidi_resolve_neutral_1 (saved_it
.prev_for_neutral
.type
,
1603 next_type
, current_level
);
1604 saved_it
.type
= type
;
1605 bidi_check_type (type
);
1606 bidi_copy_it (bidi_it
, &saved_it
);
1612 /* Given an iterator state in BIDI_IT, advance one character position
1613 in the buffer to the next character (in the logical order), resolve
1614 the bidi type of that next character, and return that type. */
1616 bidi_type_of_next_char (struct bidi_it
*bidi_it
)
1620 /* This should always be called during a forward scan. */
1621 if (bidi_it
->scan_dir
!= 1)
1624 /* Reset the limit until which to ignore BNs if we step out of the
1625 area where we found only empty levels. */
1626 if ((bidi_it
->ignore_bn_limit
> 0
1627 && bidi_it
->ignore_bn_limit
<= bidi_it
->charpos
)
1628 || (bidi_it
->ignore_bn_limit
== -1
1629 && !bidi_explicit_dir_char (bidi_it
->ch
)))
1630 bidi_it
->ignore_bn_limit
= 0;
1632 type
= bidi_resolve_neutral (bidi_it
);
1637 /* Given an iterator state BIDI_IT, advance one character position in
1638 the buffer to the next character (in the logical order), resolve
1639 the embedding and implicit levels of that next character, and
1640 return the resulting level. */
1642 bidi_level_of_next_char (struct bidi_it
*bidi_it
)
1645 int level
, prev_level
= -1;
1646 struct bidi_saved_info next_for_neutral
;
1648 if (bidi_it
->scan_dir
== 1)
1650 /* There's no sense in trying to advance if we hit end of text. */
1651 if (bidi_it
->ch
== BIDI_EOB
)
1652 return bidi_it
->resolved_level
;
1654 /* Record the info about the previous character. */
1655 if (bidi_it
->type_after_w1
!= WEAK_BN
/* W1/Retaining */
1656 && bidi_it
->type
!= WEAK_BN
)
1657 bidi_remember_char (&bidi_it
->prev
, bidi_it
);
1658 if (bidi_it
->type_after_w1
== STRONG_R
1659 || bidi_it
->type_after_w1
== STRONG_L
1660 || bidi_it
->type_after_w1
== STRONG_AL
)
1661 bidi_remember_char (&bidi_it
->last_strong
, bidi_it
);
1662 /* FIXME: it sounds like we don't need both prev and
1663 prev_for_neutral members, but I'm leaving them both for now. */
1664 if (bidi_it
->type
== STRONG_R
|| bidi_it
->type
== STRONG_L
1665 || bidi_it
->type
== WEAK_EN
|| bidi_it
->type
== WEAK_AN
)
1666 bidi_remember_char (&bidi_it
->prev_for_neutral
, bidi_it
);
1668 /* If we overstepped the characters used for resolving neutrals
1669 and whitespace, invalidate their info in the iterator. */
1670 if (bidi_it
->charpos
>= bidi_it
->next_for_neutral
.charpos
)
1671 bidi_it
->next_for_neutral
.type
= UNKNOWN_BT
;
1672 if (bidi_it
->next_en_pos
>= 0
1673 && bidi_it
->charpos
>= bidi_it
->next_en_pos
)
1674 bidi_it
->next_en_pos
= -1;
1675 if (bidi_it
->next_for_ws
.type
!= UNKNOWN_BT
1676 && bidi_it
->charpos
>= bidi_it
->next_for_ws
.charpos
)
1677 bidi_it
->next_for_ws
.type
= UNKNOWN_BT
;
1679 /* This must be taken before we fill the iterator with the info
1680 about the next char. If we scan backwards, the iterator
1681 state must be already cached, so there's no need to know the
1682 embedding level of the previous character, since we will be
1683 returning to our caller shortly. */
1684 prev_level
= bidi_it
->level_stack
[bidi_it
->stack_idx
].level
;
1686 next_for_neutral
= bidi_it
->next_for_neutral
;
1688 /* Perhaps it is already cached. */
1689 type
= bidi_cache_find (bidi_it
->charpos
+ bidi_it
->scan_dir
, -1, bidi_it
);
1690 if (type
!= UNKNOWN_BT
)
1692 /* Don't lose the information for resolving neutrals! The
1693 cached states could have been cached before their
1694 next_for_neutral member was computed. If we are on our way
1695 forward, we can simply take the info from the previous
1697 if (bidi_it
->scan_dir
== 1
1698 && bidi_it
->next_for_neutral
.type
== UNKNOWN_BT
)
1699 bidi_it
->next_for_neutral
= next_for_neutral
;
1701 /* If resolved_level is -1, it means this state was cached
1702 before it was completely resolved, so we cannot return
1704 if (bidi_it
->resolved_level
!= -1)
1705 return bidi_it
->resolved_level
;
1707 if (bidi_it
->scan_dir
== -1)
1708 /* If we are going backwards, the iterator state is already cached
1709 from previous scans, and should be fully resolved. */
1712 if (type
== UNKNOWN_BT
)
1713 type
= bidi_type_of_next_char (bidi_it
);
1715 if (type
== NEUTRAL_B
)
1716 return bidi_it
->resolved_level
;
1718 level
= bidi_it
->level_stack
[bidi_it
->stack_idx
].level
;
1719 if ((bidi_get_category (type
) == NEUTRAL
/* && type != NEUTRAL_B */)
1720 || (type
== WEAK_BN
&& prev_level
== level
))
1722 if (bidi_it
->next_for_neutral
.type
== UNKNOWN_BT
)
1725 /* If the cached state shows a neutral character, it was not
1726 resolved by bidi_resolve_neutral, so do it now. */
1727 type
= bidi_resolve_neutral_1 (bidi_it
->prev_for_neutral
.type
,
1728 bidi_it
->next_for_neutral
.type
,
1732 if (!(type
== STRONG_R
1736 || type
== WEAK_AN
))
1738 bidi_it
->type
= type
;
1739 bidi_check_type (bidi_it
->type
);
1741 /* For L1 below, we need to know, for each WS character, whether
1742 it belongs to a sequence of WS characters preceeding a newline
1743 or a TAB or a paragraph separator. */
1744 if (bidi_it
->orig_type
== NEUTRAL_WS
1745 && bidi_it
->next_for_ws
.type
== UNKNOWN_BT
)
1748 int clen
= bidi_it
->ch_len
;
1749 EMACS_INT bpos
= bidi_it
->bytepos
;
1750 EMACS_INT cpos
= bidi_it
->charpos
;
1754 /*_fetch_multibyte_char_len = 1;*/
1755 ch
= bpos
+ clen
>= ZV_BYTE
? BIDI_EOB
: FETCH_CHAR (bpos
+ clen
);
1758 clen
= (ch
== BIDI_EOB
? 1 : CHAR_BYTES (ch
));
1759 if (ch
== '\n' || ch
== BIDI_EOB
/* || ch == LINESEP_CHAR */)
1762 chtype
= bidi_get_type (ch
, NEUTRAL_DIR
);
1763 } while (chtype
== NEUTRAL_WS
|| chtype
== WEAK_BN
1764 || bidi_explicit_dir_char (ch
)); /* L1/Retaining */
1765 bidi_it
->next_for_ws
.type
= chtype
;
1766 bidi_check_type (bidi_it
->next_for_ws
.type
);
1767 bidi_it
->next_for_ws
.charpos
= cpos
;
1768 bidi_it
->next_for_ws
.bytepos
= bpos
;
1771 /* Resolve implicit levels, with a twist: PDFs get the embedding
1772 level of the enbedding they terminate. See below for the
1774 if (bidi_it
->orig_type
== PDF
1775 /* Don't do this if this formatting code didn't change the
1776 embedding level due to invalid or empty embeddings. */
1777 && prev_level
!= level
)
1779 /* Don't look in UAX#9 for the reason for this: it's our own
1780 private quirk. The reason is that we want the formatting
1781 codes to be delivered so that they bracket the text of their
1782 embedding. For example, given the text
1786 we want it to be displayed as
1794 which will result because we bump up the embedding level as
1795 soon as we see the RLO and pop it as soon as we see the PDF,
1796 so RLO itself has the same embedding level as "teST", and
1797 thus would be normally delivered last, just before the PDF.
1798 The switch below fiddles with the level of PDF so that this
1799 ugly side effect does not happen.
1801 (This is, of course, only important if the formatting codes
1802 are actually displayed, but Emacs does need to display them
1803 if the user wants to.) */
1806 else if (bidi_it
->orig_type
== NEUTRAL_B
/* L1 */
1807 || bidi_it
->orig_type
== NEUTRAL_S
1808 || bidi_it
->ch
== '\n' || bidi_it
->ch
== BIDI_EOB
1809 /* || bidi_it->ch == LINESEP_CHAR */
1810 || (bidi_it
->orig_type
== NEUTRAL_WS
1811 && (bidi_it
->next_for_ws
.type
== NEUTRAL_B
1812 || bidi_it
->next_for_ws
.type
== NEUTRAL_S
)))
1813 level
= bidi_it
->level_stack
[0].level
;
1814 else if ((level
& 1) == 0) /* I1 */
1816 if (type
== STRONG_R
)
1818 else if (type
== WEAK_EN
|| type
== WEAK_AN
)
1823 if (type
== STRONG_L
|| type
== WEAK_EN
|| type
== WEAK_AN
)
1827 bidi_it
->resolved_level
= level
;
1831 /* Move to the other edge of a level given by LEVEL. If END_FLAG is
1832 non-zero, we are at the end of a level, and we need to prepare to
1833 resume the scan of the lower level.
1835 If this level's other edge is cached, we simply jump to it, filling
1836 the iterator structure with the iterator state on the other edge.
1837 Otherwise, we walk the buffer until we come back to the same level
1840 Note: we are not talking here about a ``level run'' in the UAX#9
1841 sense of the term, but rather about a ``level'' which includes
1842 all the levels higher than it. In other words, given the levels
1845 11111112222222333333334443343222222111111112223322111
1848 and assuming we are at point A scanning left to right, this
1849 function moves to point C, whereas the UAX#9 ``level 2 run'' ends
1852 bidi_find_other_level_edge (struct bidi_it
*bidi_it
, int level
, int end_flag
)
1854 int dir
= end_flag
? -bidi_it
->scan_dir
: bidi_it
->scan_dir
;
1857 /* Try the cache first. */
1858 if ((idx
= bidi_cache_find_level_change (level
, dir
, end_flag
)) >= 0)
1859 bidi_cache_fetch_state (idx
, bidi_it
);
1865 abort (); /* if we are at end of level, its edges must be cached */
1867 bidi_cache_iterator_state (bidi_it
, 1);
1869 new_level
= bidi_level_of_next_char (bidi_it
);
1870 bidi_cache_iterator_state (bidi_it
, 1);
1871 } while (new_level
>= level
);
1876 bidi_get_next_char_visually (struct bidi_it
*bidi_it
)
1878 int old_level
, new_level
, next_level
;
1879 struct bidi_it sentinel
;
1881 if (bidi_it
->scan_dir
== 0)
1883 bidi_it
->scan_dir
= 1; /* default to logical order */
1886 /* If we just passed a newline, initialize for the next line. */
1887 if (!bidi_it
->first_elt
&& bidi_it
->orig_type
== NEUTRAL_B
)
1888 bidi_line_init (bidi_it
);
1890 /* Prepare the sentinel iterator state. */
1891 if (bidi_cache_idx
== 0)
1893 bidi_copy_it (&sentinel
, bidi_it
);
1894 if (bidi_it
->first_elt
)
1896 sentinel
.charpos
--; /* cached charpos needs to be monotonic */
1898 sentinel
.ch
= '\n'; /* doesn't matter, but why not? */
1899 sentinel
.ch_len
= 1;
1903 old_level
= bidi_it
->resolved_level
;
1904 new_level
= bidi_level_of_next_char (bidi_it
);
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 text whenever we find a level change. */
1909 if (new_level
!= old_level
)
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
;
1916 /* If we don't have anything cached yet, we need to cache the
1917 sentinel state, since we'll need it to record where to jump
1918 when the last non-base level is exhausted. */
1919 if (bidi_cache_idx
== 0)
1920 bidi_cache_iterator_state (&sentinel
, 1);
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
1925 bidi_it
->scan_dir
= -bidi_it
->scan_dir
;
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:
1937 (where the numbers below the text show the resolved levels),
1938 the result of reordering according to UAX#9 should be this:
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
)
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
);
1956 /* Finally, deliver the next character in the new direction. */
1957 next_level
= bidi_level_of_next_char (bidi_it
);
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, whereas we _must_ know the paragraph base direction
1967 _before_ we process the paragraph's text, since the base
1968 direction affects the reordering. */
1969 if (bidi_it
->scan_dir
== 1
1970 && bidi_it
->orig_type
== NEUTRAL_B
1971 && bidi_it
->bytepos
< ZV_BYTE
)
1974 bidi_at_paragraph_end (bidi_it
->charpos
+ 1,
1975 bidi_it
->bytepos
+ bidi_it
->ch_len
);
1978 bidi_it
->new_paragraph
= 1;
1979 /* Record the buffer position of the last character of the
1980 paragraph separator. */
1981 bidi_it
->separator_limit
= bidi_it
->charpos
+ 1 + sep_len
;
1985 if (bidi_it
->scan_dir
== 1 && bidi_cache_idx
)
1987 /* If we are at paragraph's base embedding level and beyond the
1988 last cached position, the cache's job is done and we can
1990 if (bidi_it
->resolved_level
== bidi_it
->level_stack
[0].level
1991 && bidi_it
->charpos
> bidi_cache
[bidi_cache_idx
- 1].charpos
)
1992 bidi_cache_reset ();
1993 /* But as long as we are caching during forward scan, we must
1994 cache each state, or else the cache integrity will be
1995 compromised: it assumes cached states correspond to buffer
1998 bidi_cache_iterator_state (bidi_it
, 1);
2002 /* This is meant to be called from within the debugger, whenever you
2003 wish to examine the cache contents. */
2005 bidi_dump_cached_states (void)
2010 if (bidi_cache_idx
== 0)
2012 fprintf (stderr
, "The cache is empty.\n");
2015 fprintf (stderr
, "Total of %d state%s in cache:\n",
2016 bidi_cache_idx
, bidi_cache_idx
== 1 ? "" : "s");
2018 for (i
= bidi_cache
[bidi_cache_idx
- 1].charpos
; i
> 0; i
/= 10)
2020 fputs ("ch ", stderr
);
2021 for (i
= 0; i
< bidi_cache_idx
; i
++)
2022 fprintf (stderr
, "%*c", ndigits
, bidi_cache
[i
].ch
);
2023 fputs ("\n", stderr
);
2024 fputs ("lvl ", stderr
);
2025 for (i
= 0; i
< bidi_cache_idx
; i
++)
2026 fprintf (stderr
, "%*d", ndigits
, bidi_cache
[i
].resolved_level
);
2027 fputs ("\n", stderr
);
2028 fputs ("pos ", stderr
);
2029 for (i
= 0; i
< bidi_cache_idx
; i
++)
2030 fprintf (stderr
, "%*d", ndigits
, bidi_cache
[i
].charpos
);
2031 fputs ("\n", stderr
);