1 /* Low-level bidirectional buffer-scanning functions for GNU Emacs.
2 Copyright (C) 2000, 2001, 2004, 2005, 2009 Free Software Foundation, Inc.
4 This file is part of GNU Emacs.
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)
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.
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. */
22 /* Written by Eli Zaretskii <eliz@gnu.org>.
24 A sequential implementation of the Unicode Bidirectional algorithm,
25 as per UAX#9, a part of the Unicode Standard.
27 Unlike the reference and most other implementations, this one is
28 designed to be called once for every character in the buffer.
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.
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.
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". */
62 #include "character.h"
63 #include "dispextern.h"
65 static int bidi_initialized
= 0;
67 static Lisp_Object bidi_type_table
;
69 /* FIXME: Remove these when bidi_explicit_dir_char uses a lookup table. */
70 #define LRM_CHAR 0x200E
71 #define RLM_CHAR 0x200F
72 #define LRE_CHAR 0x202A
73 #define RLE_CHAR 0x202B
74 #define PDF_CHAR 0x202C
75 #define LRO_CHAR 0x202D
76 #define RLO_CHAR 0x202E
79 #define BIDI_BOB -2 /* FIXME: Is this needed? */
81 /* Local data structures. (Look in dispextern.h for the rest.) */
83 /* What we need to know about the current paragraph. */
84 struct bidi_paragraph_info
{
85 int start_bytepos
; /* byte position where it begins */
86 int end_bytepos
; /* byte position where it ends */
87 int embedding_level
; /* its basic embedding level */
88 bidi_dir_t base_dir
; /* its base direction */
91 /* Data type for describing the bidirectional character categories. */
99 int bidi_ignore_explicit_marks_for_paragraph_level
= 1;
101 static Lisp_Object fallback_paragraph_start_re
, fallback_paragraph_separate_re
;
102 static Lisp_Object Qparagraph_start
, Qparagraph_separate
;
107 /* FIXME: This should come from the Unicode Database. */
112 { { 0x0000, 0x0008, WEAK_BN
},
113 { 0x0009, 0x0000, NEUTRAL_S
},
114 { 0x000A, 0x0000, NEUTRAL_B
},
115 { 0x000B, 0x0000, NEUTRAL_S
},
116 { 0x000C, 0x0000, NEUTRAL_WS
},
117 { 0x000D, 0x0000, NEUTRAL_B
},
118 { 0x000E, 0x001B, WEAK_BN
},
119 { 0x001C, 0x001E, NEUTRAL_B
},
120 { 0x001F, 0x0000, NEUTRAL_S
},
121 { 0x0020, 0x0000, NEUTRAL_WS
},
122 { 0x0021, 0x0022, NEUTRAL_ON
},
123 { 0x0023, 0x0025, WEAK_ET
},
124 { 0x0026, 0x002A, NEUTRAL_ON
},
125 { 0x002B, 0x0000, WEAK_ES
},
126 { 0x002C, 0x0000, WEAK_CS
},
127 { 0x002D, 0x0000, WEAK_ES
},
128 { 0x002E, 0x002F, WEAK_CS
},
129 { 0x0030, 0x0039, WEAK_EN
},
130 { 0x003A, 0x0000, WEAK_CS
},
131 { 0x003B, 0x0040, NEUTRAL_ON
},
132 { 0x005B, 0x0060, NEUTRAL_ON
},
133 { 0x007B, 0x007E, NEUTRAL_ON
},
134 { 0x007F, 0x0084, WEAK_BN
},
135 { 0x0085, 0x0000, NEUTRAL_B
},
136 { 0x0086, 0x009F, WEAK_BN
},
137 { 0x00A0, 0x0000, WEAK_CS
},
138 { 0x00A1, 0x0000, NEUTRAL_ON
},
139 { 0x00A2, 0x00A5, WEAK_ET
},
140 { 0x00A6, 0x00A9, NEUTRAL_ON
},
141 { 0x00AB, 0x00AC, NEUTRAL_ON
},
142 { 0x00AD, 0x0000, WEAK_BN
},
143 { 0x00AE, 0x00Af, NEUTRAL_ON
},
144 { 0x00B0, 0x00B1, WEAK_ET
},
145 { 0x00B2, 0x00B3, WEAK_EN
},
146 { 0x00B4, 0x0000, NEUTRAL_ON
},
147 { 0x00B6, 0x00B8, NEUTRAL_ON
},
148 { 0x00B9, 0x0000, WEAK_EN
},
149 { 0x00BB, 0x00BF, NEUTRAL_ON
},
150 { 0x00D7, 0x0000, NEUTRAL_ON
},
151 { 0x00F7, 0x0000, NEUTRAL_ON
},
152 { 0x02B9, 0x02BA, NEUTRAL_ON
},
153 { 0x02C2, 0x02CF, NEUTRAL_ON
},
154 { 0x02D2, 0x02DF, NEUTRAL_ON
},
155 { 0x02E5, 0x02ED, NEUTRAL_ON
},
156 { 0x0300, 0x036F, WEAK_NSM
},
157 { 0x0374, 0x0375, NEUTRAL_ON
},
158 { 0x037E, 0x0385, NEUTRAL_ON
},
159 { 0x0387, 0x0000, NEUTRAL_ON
},
160 { 0x03F6, 0x0000, NEUTRAL_ON
},
161 { 0x0483, 0x0489, WEAK_NSM
},
162 { 0x058A, 0x0000, NEUTRAL_ON
},
163 { 0x0591, 0x05BD, WEAK_NSM
},
164 { 0x05BE, 0x0000, STRONG_R
},
165 { 0x05BF, 0x0000, WEAK_NSM
},
166 { 0x05C0, 0x0000, STRONG_R
},
167 { 0x05C1, 0x05C2, WEAK_NSM
},
168 { 0x05C3, 0x0000, STRONG_R
},
169 { 0x05C4, 0x05C5, WEAK_NSM
},
170 { 0x05C6, 0x0000, STRONG_R
},
171 { 0x05C7, 0x0000, WEAK_NSM
},
172 { 0x05D0, 0x05F4, STRONG_R
},
173 { 0x060C, 0x0000, WEAK_CS
},
174 { 0x061B, 0x064A, STRONG_AL
},
175 { 0x064B, 0x0655, WEAK_NSM
},
176 { 0x0660, 0x0669, WEAK_AN
},
177 { 0x066A, 0x0000, WEAK_ET
},
178 { 0x066B, 0x066C, WEAK_AN
},
179 { 0x066D, 0x066F, STRONG_AL
},
180 { 0x0670, 0x0000, WEAK_NSM
},
181 { 0x0671, 0x06D5, STRONG_AL
},
182 { 0x06D6, 0x06DC, WEAK_NSM
},
183 { 0x06DD, 0x0000, STRONG_AL
},
184 { 0x06DE, 0x06E4, WEAK_NSM
},
185 { 0x06E5, 0x06E6, STRONG_AL
},
186 { 0x06E7, 0x06E8, WEAK_NSM
},
187 { 0x06E9, 0x0000, NEUTRAL_ON
},
188 { 0x06EA, 0x06ED, WEAK_NSM
},
189 { 0x06F0, 0x06F9, WEAK_EN
},
190 { 0x06FA, 0x070D, STRONG_AL
},
191 { 0x070F, 0x0000, WEAK_BN
},
192 { 0x0710, 0x0000, STRONG_AL
},
193 { 0x0711, 0x0000, WEAK_NSM
},
194 { 0x0712, 0x072C, STRONG_AL
},
195 { 0x0730, 0x074A, WEAK_NSM
},
196 { 0x0780, 0x07A5, STRONG_AL
},
197 { 0x07A6, 0x07B0, WEAK_NSM
},
198 { 0x07B1, 0x0000, STRONG_AL
},
199 { 0x0901, 0x0902, WEAK_NSM
},
200 { 0x093C, 0x0000, WEAK_NSM
},
201 { 0x0941, 0x0948, WEAK_NSM
},
202 { 0x094D, 0x0000, WEAK_NSM
},
203 { 0x0951, 0x0954, WEAK_NSM
},
204 { 0x0962, 0x0963, WEAK_NSM
},
205 { 0x0981, 0x0000, WEAK_NSM
},
206 { 0x09BC, 0x0000, WEAK_NSM
},
207 { 0x09C1, 0x09C4, WEAK_NSM
},
208 { 0x09CD, 0x0000, WEAK_NSM
},
209 { 0x09E2, 0x09E3, WEAK_NSM
},
210 { 0x09F2, 0x09F3, WEAK_ET
},
211 { 0x0A02, 0x0000, WEAK_NSM
},
212 { 0x0A3C, 0x0000, WEAK_NSM
},
213 { 0x0A41, 0x0A4D, WEAK_NSM
},
214 { 0x0A70, 0x0A71, WEAK_NSM
},
215 { 0x0A81, 0x0A82, WEAK_NSM
},
216 { 0x0ABC, 0x0000, WEAK_NSM
},
217 { 0x0AC1, 0x0AC8, WEAK_NSM
},
218 { 0x0ACD, 0x0000, WEAK_NSM
},
219 { 0x0B01, 0x0000, WEAK_NSM
},
220 { 0x0B3C, 0x0000, WEAK_NSM
},
221 { 0x0B3F, 0x0000, WEAK_NSM
},
222 { 0x0B41, 0x0B43, WEAK_NSM
},
223 { 0x0B4D, 0x0B56, WEAK_NSM
},
224 { 0x0B82, 0x0000, WEAK_NSM
},
225 { 0x0BC0, 0x0000, WEAK_NSM
},
226 { 0x0BCD, 0x0000, WEAK_NSM
},
227 { 0x0C3E, 0x0C40, WEAK_NSM
},
228 { 0x0C46, 0x0C56, WEAK_NSM
},
229 { 0x0CBF, 0x0000, WEAK_NSM
},
230 { 0x0CC6, 0x0000, WEAK_NSM
},
231 { 0x0CCC, 0x0CCD, WEAK_NSM
},
232 { 0x0D41, 0x0D43, WEAK_NSM
},
233 { 0x0D4D, 0x0000, WEAK_NSM
},
234 { 0x0DCA, 0x0000, WEAK_NSM
},
235 { 0x0DD2, 0x0DD6, WEAK_NSM
},
236 { 0x0E31, 0x0000, WEAK_NSM
},
237 { 0x0E34, 0x0E3A, WEAK_NSM
},
238 { 0x0E3F, 0x0000, WEAK_ET
},
239 { 0x0E47, 0x0E4E, WEAK_NSM
},
240 { 0x0EB1, 0x0000, WEAK_NSM
},
241 { 0x0EB4, 0x0EBC, WEAK_NSM
},
242 { 0x0EC8, 0x0ECD, WEAK_NSM
},
243 { 0x0F18, 0x0F19, WEAK_NSM
},
244 { 0x0F35, 0x0000, WEAK_NSM
},
245 { 0x0F37, 0x0000, WEAK_NSM
},
246 { 0x0F39, 0x0000, WEAK_NSM
},
247 { 0x0F3A, 0x0F3D, NEUTRAL_ON
},
248 { 0x0F71, 0x0F7E, WEAK_NSM
},
249 { 0x0F80, 0x0F84, WEAK_NSM
},
250 { 0x0F86, 0x0F87, WEAK_NSM
},
251 { 0x0F90, 0x0FBC, WEAK_NSM
},
252 { 0x0FC6, 0x0000, WEAK_NSM
},
253 { 0x102D, 0x1030, WEAK_NSM
},
254 { 0x1032, 0x1037, WEAK_NSM
},
255 { 0x1039, 0x0000, WEAK_NSM
},
256 { 0x1058, 0x1059, WEAK_NSM
},
257 { 0x1680, 0x0000, NEUTRAL_WS
},
258 { 0x169B, 0x169C, NEUTRAL_ON
},
259 { 0x1712, 0x1714, WEAK_NSM
},
260 { 0x1732, 0x1734, WEAK_NSM
},
261 { 0x1752, 0x1753, WEAK_NSM
},
262 { 0x1772, 0x1773, WEAK_NSM
},
263 { 0x17B7, 0x17BD, WEAK_NSM
},
264 { 0x17C6, 0x0000, WEAK_NSM
},
265 { 0x17C9, 0x17D3, WEAK_NSM
},
266 { 0x17DB, 0x0000, WEAK_ET
},
267 { 0x1800, 0x180A, NEUTRAL_ON
},
268 { 0x180B, 0x180D, WEAK_NSM
},
269 { 0x180E, 0x0000, WEAK_BN
},
270 { 0x18A9, 0x0000, WEAK_NSM
},
271 { 0x1FBD, 0x0000, NEUTRAL_ON
},
272 { 0x1FBF, 0x1FC1, NEUTRAL_ON
},
273 { 0x1FCD, 0x1FCF, NEUTRAL_ON
},
274 { 0x1FDD, 0x1FDF, NEUTRAL_ON
},
275 { 0x1FED, 0x1FEF, NEUTRAL_ON
},
276 { 0x1FFD, 0x1FFE, NEUTRAL_ON
},
277 { 0x2000, 0x200A, NEUTRAL_WS
},
278 { 0x200B, 0x200D, WEAK_BN
},
279 { 0x200F, 0x0000, STRONG_R
},
280 { 0x2010, 0x2027, NEUTRAL_ON
},
281 { 0x2028, 0x0000, NEUTRAL_WS
},
282 { 0x2029, 0x0000, NEUTRAL_B
},
283 { 0x202A, 0x0000, LRE
},
284 { 0x202B, 0x0000, RLE
},
285 { 0x202C, 0x0000, PDF
},
286 { 0x202D, 0x0000, LRO
},
287 { 0x202E, 0x0000, RLO
},
288 { 0x202F, 0x0000, NEUTRAL_WS
},
289 { 0x2030, 0x2034, WEAK_ET
},
290 { 0x2035, 0x2057, NEUTRAL_ON
},
291 { 0x205F, 0x0000, NEUTRAL_WS
},
292 { 0x2060, 0x206F, WEAK_BN
},
293 { 0x2070, 0x0000, WEAK_EN
},
294 { 0x2074, 0x2079, WEAK_EN
},
295 { 0x207A, 0x207B, WEAK_ET
},
296 { 0x207C, 0x207E, NEUTRAL_ON
},
297 { 0x2080, 0x2089, WEAK_EN
},
298 { 0x208A, 0x208B, WEAK_ET
},
299 { 0x208C, 0x208E, NEUTRAL_ON
},
300 { 0x20A0, 0x20B1, WEAK_ET
},
301 { 0x20D0, 0x20EA, WEAK_NSM
},
302 { 0x2100, 0x2101, NEUTRAL_ON
},
303 { 0x2103, 0x2106, NEUTRAL_ON
},
304 { 0x2108, 0x2109, NEUTRAL_ON
},
305 { 0x2114, 0x0000, NEUTRAL_ON
},
306 { 0x2116, 0x2118, NEUTRAL_ON
},
307 { 0x211E, 0x2123, NEUTRAL_ON
},
308 { 0x2125, 0x0000, NEUTRAL_ON
},
309 { 0x2127, 0x0000, NEUTRAL_ON
},
310 { 0x2129, 0x0000, NEUTRAL_ON
},
311 { 0x212E, 0x0000, WEAK_ET
},
312 { 0x2132, 0x0000, NEUTRAL_ON
},
313 { 0x213A, 0x0000, NEUTRAL_ON
},
314 { 0x2140, 0x2144, NEUTRAL_ON
},
315 { 0x214A, 0x215F, NEUTRAL_ON
},
316 { 0x2190, 0x2211, NEUTRAL_ON
},
317 { 0x2212, 0x2213, WEAK_ET
},
318 { 0x2214, 0x2335, NEUTRAL_ON
},
319 { 0x237B, 0x2394, NEUTRAL_ON
},
320 { 0x2396, 0x244A, NEUTRAL_ON
},
321 { 0x2460, 0x249B, WEAK_EN
},
322 { 0x24EA, 0x0000, WEAK_EN
},
323 { 0x24EB, 0x2FFB, NEUTRAL_ON
},
324 { 0x3000, 0x0000, NEUTRAL_WS
},
325 { 0x3001, 0x3004, NEUTRAL_ON
},
326 { 0x3008, 0x3020, NEUTRAL_ON
},
327 { 0x302A, 0x302F, WEAK_NSM
},
328 { 0x3030, 0x0000, NEUTRAL_ON
},
329 { 0x3036, 0x3037, NEUTRAL_ON
},
330 { 0x303D, 0x303F, NEUTRAL_ON
},
331 { 0x3099, 0x309A, WEAK_NSM
},
332 { 0x309B, 0x309C, NEUTRAL_ON
},
333 { 0x30A0, 0x0000, NEUTRAL_ON
},
334 { 0x30FB, 0x0000, NEUTRAL_ON
},
335 { 0x3251, 0x325F, NEUTRAL_ON
},
336 { 0x32B1, 0x32BF, NEUTRAL_ON
},
337 { 0xA490, 0xA4C6, NEUTRAL_ON
},
338 { 0xFB1D, 0x0000, STRONG_R
},
339 { 0xFB1E, 0x0000, WEAK_NSM
},
340 { 0xFB1F, 0xFB28, STRONG_R
},
341 { 0xFB29, 0x0000, WEAK_ET
},
342 { 0xFB2A, 0xFB4F, STRONG_R
},
343 { 0xFB50, 0xFD3D, STRONG_AL
},
344 { 0xFD3E, 0xFD3F, NEUTRAL_ON
},
345 { 0xFD50, 0xFDFC, STRONG_AL
},
346 { 0xFE00, 0xFE23, WEAK_NSM
},
347 { 0xFE30, 0xFE4F, NEUTRAL_ON
},
348 { 0xFE50, 0x0000, WEAK_CS
},
349 { 0xFE51, 0x0000, NEUTRAL_ON
},
350 { 0xFE52, 0x0000, WEAK_CS
},
351 { 0xFE54, 0x0000, NEUTRAL_ON
},
352 { 0xFE55, 0x0000, WEAK_CS
},
353 { 0xFE56, 0xFE5E, NEUTRAL_ON
},
354 { 0xFE5F, 0x0000, WEAK_ET
},
355 { 0xFE60, 0xFE61, NEUTRAL_ON
},
356 { 0xFE62, 0xFE63, WEAK_ET
},
357 { 0xFE64, 0xFE68, NEUTRAL_ON
},
358 { 0xFE69, 0xFE6A, WEAK_ET
},
359 { 0xFE6B, 0x0000, NEUTRAL_ON
},
360 { 0xFE70, 0xFEFC, STRONG_AL
},
361 { 0xFEFF, 0x0000, WEAK_BN
},
362 { 0xFF01, 0xFF02, NEUTRAL_ON
},
363 { 0xFF03, 0xFF05, WEAK_ET
},
364 { 0xFF06, 0xFF0A, NEUTRAL_ON
},
365 { 0xFF0B, 0x0000, WEAK_ET
},
366 { 0xFF0C, 0x0000, WEAK_CS
},
367 { 0xFF0D, 0x0000, WEAK_ET
},
368 { 0xFF0E, 0x0000, WEAK_CS
},
369 { 0xFF0F, 0x0000, WEAK_ES
},
370 { 0xFF10, 0xFF19, WEAK_EN
},
371 { 0xFF1A, 0x0000, WEAK_CS
},
372 { 0xFF1B, 0xFF20, NEUTRAL_ON
},
373 { 0xFF3B, 0xFF40, NEUTRAL_ON
},
374 { 0xFF5B, 0xFF65, NEUTRAL_ON
},
375 { 0xFFE0, 0xFFE1, WEAK_ET
},
376 { 0xFFE2, 0xFFE4, NEUTRAL_ON
},
377 { 0xFFE5, 0xFFE6, WEAK_ET
},
378 { 0xFFE8, 0xFFEE, NEUTRAL_ON
},
379 { 0xFFF9, 0xFFFB, WEAK_BN
},
380 { 0xFFFC, 0xFFFD, NEUTRAL_ON
},
381 { 0x1D167, 0x1D169, WEAK_NSM
},
382 { 0x1D173, 0x1D17A, WEAK_BN
},
383 { 0x1D17B, 0x1D182, WEAK_NSM
},
384 { 0x1D185, 0x1D18B, WEAK_NSM
},
385 { 0x1D1AA, 0x1D1AD, WEAK_NSM
},
386 { 0x1D7CE, 0x1D7FF, WEAK_EN
},
387 { 0xE0001, 0xE007F, WEAK_BN
} };
390 bidi_type_table
= Fmake_char_table (Qnil
, make_number (STRONG_L
));
391 staticpro (&bidi_type_table
);
393 for (i
= 0; i
< sizeof bidi_type
/ sizeof bidi_type
[0]; i
++)
394 char_table_set_range (bidi_type_table
, bidi_type
[i
].from
,
395 bidi_type
[i
].to
? bidi_type
[i
].to
: bidi_type
[i
].from
,
396 make_number (bidi_type
[i
].type
));
398 fallback_paragraph_start_re
=
399 XSYMBOL (Fintern_soft (build_string ("paragraph-start"), Qnil
))->value
;
400 if (!STRINGP (fallback_paragraph_start_re
))
401 fallback_paragraph_start_re
= build_string ("\f\\|[ \t]*$");
402 staticpro (&fallback_paragraph_start_re
);
403 Qparagraph_start
= intern ("paragraph-start");
404 staticpro (&Qparagraph_start
);
405 fallback_paragraph_separate_re
=
406 XSYMBOL (Fintern_soft (build_string ("paragraph-separate"), Qnil
))->value
;
407 if (!STRINGP (fallback_paragraph_separate_re
))
408 fallback_paragraph_separate_re
= build_string ("[ \t\f]*$");
409 staticpro (&fallback_paragraph_separate_re
);
410 Qparagraph_separate
= intern ("paragraph-separate");
411 staticpro (&Qparagraph_separate
);
412 bidi_initialized
= 1;
415 /* Return the bidi type of a character CH, subject to the current
416 directional OVERRIDE. */
418 bidi_get_type (int ch
, bidi_dir_t override
)
420 bidi_type_t default_type
;
424 if (ch
< 0 || ch
> MAX_CHAR
)
427 default_type
= (bidi_type_t
) XINT (CHAR_TABLE_REF (bidi_type_table
, ch
));
429 if (override
== NEUTRAL_DIR
)
432 switch (default_type
)
434 /* Although UAX#9 does not tell, it doesn't make sense to
435 override NEUTRAL_B and LRM/RLM characters. */
450 if (override
== L2R
) /* X6 */
452 else if (override
== R2L
)
455 abort (); /* can't happen: handled above */
461 bidi_check_type (bidi_type_t type
)
463 if (type
< UNKNOWN_BT
|| type
> NEUTRAL_ON
)
467 /* Given a bidi TYPE of a character, return its category. */
469 bidi_get_category (bidi_type_t type
)
483 case PDF
: /* ??? really?? */
502 /* Return the mirrored character of C, if any.
504 Note: The conditions in UAX#9 clause L4 must be tested by the
506 /* FIXME: exceedingly temporary! Should consult the Unicode database
507 of character properties. */
509 bidi_mirror_char (int c
)
511 static const char mirrored_pairs
[] = "()<>[]{}";
512 const char *p
= c
> 0 && c
< 128 ? strchr (mirrored_pairs
, c
) : NULL
;
516 size_t i
= p
- mirrored_pairs
;
518 return mirrored_pairs
[(i
^ 1)];
523 /* Copy the bidi iterator from FROM to TO. To save cycles, this only
524 copies the part of the level stack that is actually in use. */
526 bidi_copy_it (struct bidi_it
*to
, struct bidi_it
*from
)
530 /* Copy everything except the level stack and beyond. */
531 memcpy (to
, from
, ((size_t)&((struct bidi_it
*)0)->level_stack
[0]));
533 /* Copy the active part of the level stack. */
534 to
->level_stack
[0] = from
->level_stack
[0]; /* level zero is always in use */
535 for (i
= 1; i
<= from
->stack_idx
; i
++)
536 to
->level_stack
[i
] = from
->level_stack
[i
];
539 /* Caching the bidi iterator states. */
541 static struct bidi_it bidi_cache
[1000]; /* FIXME: make this dynamically allocated! */
542 static int bidi_cache_idx
;
543 static int bidi_cache_last_idx
;
546 bidi_cache_reset (void)
549 bidi_cache_last_idx
= -1;
553 bidi_cache_fetch_state (int idx
, struct bidi_it
*bidi_it
)
555 int current_scan_dir
= bidi_it
->scan_dir
;
557 if (idx
< 0 || idx
>= bidi_cache_idx
)
560 bidi_copy_it (bidi_it
, &bidi_cache
[idx
]);
561 bidi_it
->scan_dir
= current_scan_dir
;
562 bidi_cache_last_idx
= idx
;
565 /* Find a cached state with a given CHARPOS and resolved embedding
566 level less or equal to LEVEL. if LEVEL is -1, disregard the
567 resolved levels in cached states. DIR, if non-zero, means search
568 in that direction from the last cache hit. */
570 bidi_cache_search (int charpos
, int level
, int dir
)
576 if (charpos
< bidi_cache
[bidi_cache_last_idx
].charpos
)
578 else if (charpos
> bidi_cache
[bidi_cache_last_idx
].charpos
)
581 i_start
= bidi_cache_last_idx
;
585 i_start
= bidi_cache_idx
- 1;
590 /* Linear search for now; FIXME! */
591 for (i
= i_start
; i
>= 0; i
--)
592 if (bidi_cache
[i
].charpos
== charpos
593 && (level
== -1 || bidi_cache
[i
].resolved_level
<= level
))
598 for (i
= i_start
; i
< bidi_cache_idx
; i
++)
599 if (bidi_cache
[i
].charpos
== charpos
600 && (level
== -1 || bidi_cache
[i
].resolved_level
<= level
))
608 /* Find a cached state where the resolved level changes to a value
609 that is lower than LEVEL, and return its cache slot index. DIR is
610 the direction to search, starting with the last used cache slot.
611 BEFORE, if non-zero, means return the index of the slot that is
612 ``before'' the level change in the search direction. That is,
613 given the cached levels like this:
618 and assuming we are at the position cached at the slot marked with
619 C, searching backwards (DIR = -1) for LEVEL = 2 will return the
620 index of slot B or A, depending whether BEFORE is, respectively,
623 bidi_cache_find_level_change (int level
, int dir
, int before
)
627 int i
= dir
? bidi_cache_last_idx
: bidi_cache_idx
- 1;
628 int incr
= before
? 1 : 0;
639 if (bidi_cache
[i
- incr
].resolved_level
>= 0
640 && bidi_cache
[i
- incr
].resolved_level
< level
)
647 while (i
< bidi_cache_idx
- incr
)
649 if (bidi_cache
[i
+ incr
].resolved_level
>= 0
650 && bidi_cache
[i
+ incr
].resolved_level
< level
)
661 bidi_cache_iterator_state (struct bidi_it
*bidi_it
, int resolved
)
665 /* We should never cache on backward scans. */
666 if (bidi_it
->scan_dir
== -1)
668 idx
= bidi_cache_search (bidi_it
->charpos
, -1, 1);
672 idx
= bidi_cache_idx
;
673 /* Don't overrun the cache limit. */
674 if (idx
> sizeof (bidi_cache
) / sizeof (bidi_cache
[0]) - 1)
676 /* Don't violate cache integrity: character positions should
677 correspond to cache positions 1:1. */
678 if (idx
> 0 && bidi_it
->charpos
!= bidi_cache
[idx
- 1].charpos
+ 1)
680 bidi_copy_it (&bidi_cache
[idx
], bidi_it
);
682 bidi_cache
[idx
].resolved_level
= -1;
683 bidi_cache
[idx
].new_paragraph
= 0;
687 /* Copy only the members which could have changed, to avoid
688 costly copying of the entire struct. */
689 bidi_cache
[idx
].type
= bidi_it
->type
;
690 bidi_check_type (bidi_it
->type
);
691 bidi_cache
[idx
].type_after_w1
= bidi_it
->type_after_w1
;
692 bidi_check_type (bidi_it
->type_after_w1
);
694 bidi_cache
[idx
].resolved_level
= bidi_it
->resolved_level
;
696 bidi_cache
[idx
].resolved_level
= -1;
697 bidi_cache
[idx
].invalid_levels
= bidi_it
->invalid_levels
;
698 bidi_cache
[idx
].invalid_rl_levels
= bidi_it
->invalid_rl_levels
;
699 bidi_cache
[idx
].next_for_neutral
= bidi_it
->next_for_neutral
;
700 bidi_cache
[idx
].next_for_ws
= bidi_it
->next_for_ws
;
701 bidi_cache
[idx
].ignore_bn_limit
= bidi_it
->ignore_bn_limit
;
704 bidi_cache_last_idx
= idx
;
705 if (idx
>= bidi_cache_idx
)
706 bidi_cache_idx
= idx
+ 1;
709 static inline bidi_type_t
710 bidi_cache_find (int charpos
, int level
, struct bidi_it
*bidi_it
)
712 int i
= bidi_cache_search (charpos
, level
, bidi_it
->scan_dir
);
716 bidi_dir_t current_scan_dir
= bidi_it
->scan_dir
;
718 *bidi_it
= bidi_cache
[i
];
719 bidi_cache_last_idx
= i
;
720 /* Don't let scan direction from from the cached state override
721 the current scan direction. */
722 bidi_it
->scan_dir
= current_scan_dir
;
723 return bidi_it
->type
;
730 bidi_peek_at_next_level (struct bidi_it
*bidi_it
)
732 if (bidi_cache_idx
== 0 || bidi_cache_last_idx
== -1)
734 return bidi_cache
[bidi_cache_last_idx
+ bidi_it
->scan_dir
].resolved_level
;
737 /* Check if buffer position CHARPOS/BYTEPOS is the end of a paragraph.
738 Value is the non-negative length of the paragraph separator
739 following the buffer position, -1 if position is at the beginning
740 of a new paragraph, or -2 if position is neither at beginning nor
741 at end of a paragraph. */
743 bidi_at_paragraph_end (EMACS_INT charpos
, EMACS_INT bytepos
)
745 Lisp_Object sep_re
= Fbuffer_local_value (Qparagraph_separate
,
747 Lisp_Object start_re
= Fbuffer_local_value (Qparagraph_start
,
751 if (!STRINGP (sep_re
))
752 sep_re
= fallback_paragraph_separate_re
;
753 if (!STRINGP (start_re
))
754 start_re
= fallback_paragraph_start_re
;
756 val
= fast_looking_at (sep_re
, charpos
, bytepos
, ZV
, ZV_BYTE
, Qnil
);
759 if (fast_looking_at (start_re
, charpos
, bytepos
, ZV
, ZV_BYTE
, Qnil
) >= 0)
768 /* Determine the start-of-run (sor) directional type given the two
769 embedding levels on either side of the run boundary. Also, update
770 the saved info about previously seen characters, since that info is
771 generally valid for a single level run. */
773 bidi_set_sor_type (struct bidi_it
*bidi_it
, int level_before
, int level_after
)
775 int higher_level
= level_before
> level_after
? level_before
: level_after
;
777 /* The prev_was_pdf gork is required for when we have several PDFs
778 in a row. In that case, we want to compute the sor type for the
779 next level run only once: when we see the first PDF. That's
780 because the sor type depends only on the higher of the two levels
781 that we find on the two sides of the level boundary (see UAX#9,
782 clause X10), and so we don't need to know the final embedding
783 level to which we descend after processing all the PDFs. */
784 if (!bidi_it
->prev_was_pdf
|| level_before
< level_after
)
785 /* FIXME: should the default sor direction be user selectable? */
786 bidi_it
->sor
= (higher_level
& 1) != 0 ? R2L
: L2R
;
787 if (level_before
> level_after
)
788 bidi_it
->prev_was_pdf
= 1;
790 bidi_it
->prev
.type
= UNKNOWN_BT
;
791 bidi_it
->last_strong
.type
= bidi_it
->last_strong
.type_after_w1
=
792 bidi_it
->last_strong
.orig_type
= UNKNOWN_BT
;
793 bidi_it
->prev_for_neutral
.type
= bidi_it
->sor
== R2L
? STRONG_R
: STRONG_L
;
794 bidi_it
->prev_for_neutral
.charpos
= bidi_it
->charpos
;
795 bidi_it
->prev_for_neutral
.bytepos
= bidi_it
->bytepos
;
796 bidi_it
->next_for_neutral
.type
= bidi_it
->next_for_neutral
.type_after_w1
=
797 bidi_it
->next_for_neutral
.orig_type
= UNKNOWN_BT
;
798 bidi_it
->ignore_bn_limit
= 0; /* meaning it's unknown */
802 bidi_line_init (struct bidi_it
*bidi_it
)
804 bidi_it
->scan_dir
= 1; /* FIXME: do we need to have control on this? */
805 bidi_it
->resolved_level
= bidi_it
->level_stack
[0].level
;
806 bidi_it
->level_stack
[0].override
= NEUTRAL_DIR
; /* X1 */
807 bidi_it
->invalid_levels
= 0;
808 bidi_it
->invalid_rl_levels
= -1;
809 bidi_it
->next_en_pos
= -1;
810 bidi_it
->next_for_ws
.type
= UNKNOWN_BT
;
811 bidi_set_sor_type (bidi_it
,
812 bidi_it
->paragraph_dir
== R2L
? 1 : 0,
813 bidi_it
->level_stack
[0].level
); /* X10 */
818 /* Find the beginning of this paragraph by looking back in the buffer.
819 Value is the byte position of the paragraph's beginning. */
821 bidi_find_paragraph_start (EMACS_INT pos
, EMACS_INT pos_byte
)
823 Lisp_Object re
= Fbuffer_local_value (Qparagraph_start
, Fcurrent_buffer ());
824 EMACS_INT limit
= ZV
, limit_byte
= ZV_BYTE
;
827 re
= fallback_paragraph_start_re
;
828 while (pos_byte
> BEGV_BYTE
829 && fast_looking_at (re
, pos
, pos_byte
, limit
, limit_byte
, Qnil
) < 0)
831 pos
= find_next_newline_no_quit (pos
- 1, -1);
832 pos_byte
= CHAR_TO_BYTE (pos
);
837 /* Determine the direction, a.k.a. base embedding level, of the
838 paragraph we are about to iterate through. If DIR is either L2R or
839 R2L, just use that. Otherwise, determine the paragraph direction
840 from the first strong character of the paragraph.
842 Note that this gives the paragraph separator the same direction as
843 the preceding paragraph, even though Emacs generally views the
844 separartor as not belonging to any paragraph. */
846 bidi_paragraph_init (bidi_dir_t dir
, struct bidi_it
*bidi_it
)
848 EMACS_INT bytepos
= bidi_it
->bytepos
;
850 /* Special case for an empty buffer. */
851 if (bytepos
== BEGV_BYTE
&& bytepos
== ZV_BYTE
)
853 /* We should never be called at EOB or before BEGV. */
854 else if (bytepos
>= ZV_BYTE
|| bytepos
< BEGV_BYTE
)
859 bidi_it
->paragraph_dir
= L2R
;
860 bidi_it
->new_paragraph
= 0;
864 bidi_it
->paragraph_dir
= R2L
;
865 bidi_it
->new_paragraph
= 0;
867 else if (dir
== NEUTRAL_DIR
) /* P2 */
874 /* If we are inside a paragraph separator, we are just waiting
875 for the separator to be exhausted; use the previous paragraph
876 direction. But don't do that if we have been just reseated,
877 because we need to reinitialize below in that case. */
878 if (!bidi_it
->first_elt
879 && bidi_it
->charpos
< bidi_it
->separator_limit
)
882 /* If we are on a newline, get past it to where the next
883 paragraph might start. But don't do that at BEGV since then
884 we are potentially in a new paragraph that doesn't yet
886 pos
= bidi_it
->charpos
;
887 if (bytepos
> BEGV_BYTE
&& FETCH_CHAR (bytepos
) == '\n')
893 /* We are either at the beginning of a paragraph or in the
894 middle of it. Find where this paragraph starts. */
895 bytepos
= bidi_find_paragraph_start (pos
, bytepos
);
897 /* We should always be at the beginning of a new line at this
899 if (!(bytepos
== BEGV_BYTE
|| FETCH_CHAR (bytepos
- 1) == '\n'))
902 bidi_it
->separator_limit
= -1;
903 bidi_it
->new_paragraph
= 0;
904 ch
= FETCH_CHAR (bytepos
);
905 ch_len
= CHAR_BYTES (ch
);
906 pos
= BYTE_TO_CHAR (bytepos
);
907 type
= bidi_get_type (ch
, NEUTRAL_DIR
);
909 for (pos
++, bytepos
+= ch_len
;
910 /* NOTE: UAX#9 says to search only for L, AL, or R types of
911 characters, and ignore RLE, RLO, LRE, and LRO. However,
912 I'm not sure it makes sense to omit those 4; should try
913 with and without that to see the effect. */
914 (bidi_get_category (type
) != STRONG
)
915 || (bidi_ignore_explicit_marks_for_paragraph_level
916 && (type
== RLE
|| type
== RLO
917 || type
== LRE
|| type
== LRO
));
918 type
= bidi_get_type (ch
, NEUTRAL_DIR
))
920 if (type
== NEUTRAL_B
&& bidi_at_paragraph_end (pos
, bytepos
) >= -1)
922 if (bytepos
>= ZV_BYTE
)
924 /* Pretend there's a paragraph separator at end of buffer. */
928 FETCH_CHAR_ADVANCE (ch
, pos
, bytepos
);
930 if (type
== STRONG_R
|| type
== STRONG_AL
) /* P3 */
931 bidi_it
->paragraph_dir
= R2L
;
932 else if (type
== STRONG_L
)
933 bidi_it
->paragraph_dir
= L2R
;
938 /* Contrary to UAX#9 clause P3, we only default the paragraph
939 direction to L2R if we have no previous usable paragraph
941 if (bidi_it
->paragraph_dir
== NEUTRAL_DIR
)
942 bidi_it
->paragraph_dir
= L2R
; /* P3 and ``higher protocols'' */
943 if (bidi_it
->paragraph_dir
== R2L
)
944 bidi_it
->level_stack
[0].level
= 1;
946 bidi_it
->level_stack
[0].level
= 0;
948 bidi_line_init (bidi_it
);
951 /* Do whatever UAX#9 clause X8 says should be done at paragraph's
954 bidi_set_paragraph_end (struct bidi_it
*bidi_it
)
956 bidi_it
->invalid_levels
= 0;
957 bidi_it
->invalid_rl_levels
= -1;
958 bidi_it
->stack_idx
= 0;
959 bidi_it
->resolved_level
= bidi_it
->level_stack
[0].level
;
962 /* Initialize the bidi iterator from buffer position CHARPOS. */
964 bidi_init_it (EMACS_INT charpos
, EMACS_INT bytepos
, struct bidi_it
*bidi_it
)
966 if (! bidi_initialized
)
968 bidi_it
->charpos
= charpos
;
969 bidi_it
->bytepos
= bytepos
;
970 bidi_it
->first_elt
= 1;
971 bidi_set_paragraph_end (bidi_it
);
972 bidi_it
->new_paragraph
= 1;
973 bidi_it
->separator_limit
= -1;
974 bidi_it
->paragraph_dir
= NEUTRAL_DIR
;
975 bidi_it
->type
= NEUTRAL_B
;
976 bidi_it
->type_after_w1
= UNKNOWN_BT
;
977 bidi_it
->orig_type
= UNKNOWN_BT
;
978 bidi_it
->prev_was_pdf
= 0;
979 bidi_it
->prev
.type
= bidi_it
->prev
.type_after_w1
= UNKNOWN_BT
;
980 bidi_it
->last_strong
.type
= bidi_it
->last_strong
.type_after_w1
=
981 bidi_it
->last_strong
.orig_type
= UNKNOWN_BT
;
982 bidi_it
->next_for_neutral
.charpos
= -1;
983 bidi_it
->next_for_neutral
.type
=
984 bidi_it
->next_for_neutral
.type_after_w1
=
985 bidi_it
->next_for_neutral
.orig_type
= UNKNOWN_BT
;
986 bidi_it
->prev_for_neutral
.charpos
= -1;
987 bidi_it
->prev_for_neutral
.type
=
988 bidi_it
->prev_for_neutral
.type_after_w1
=
989 bidi_it
->prev_for_neutral
.orig_type
= UNKNOWN_BT
;
990 bidi_it
->sor
= L2R
; /* FIXME: should it be user-selectable? */
993 /* Push the current embedding level and override status; reset the
994 current level to LEVEL and the current override status to OVERRIDE. */
996 bidi_push_embedding_level (struct bidi_it
*bidi_it
,
997 int level
, bidi_dir_t override
)
999 bidi_it
->stack_idx
++;
1000 if (bidi_it
->stack_idx
>= BIDI_MAXLEVEL
)
1002 bidi_it
->level_stack
[bidi_it
->stack_idx
].level
= level
;
1003 bidi_it
->level_stack
[bidi_it
->stack_idx
].override
= override
;
1006 /* Pop the embedding level and directional override status from the
1007 stack, and return the new level. */
1009 bidi_pop_embedding_level (struct bidi_it
*bidi_it
)
1011 /* UAX#9 says to ignore invalid PDFs. */
1012 if (bidi_it
->stack_idx
> 0)
1013 bidi_it
->stack_idx
--;
1014 return bidi_it
->level_stack
[bidi_it
->stack_idx
].level
;
1017 /* Record in SAVED_INFO the information about the current character. */
1019 bidi_remember_char (struct bidi_saved_info
*saved_info
,
1020 struct bidi_it
*bidi_it
)
1022 saved_info
->charpos
= bidi_it
->charpos
;
1023 saved_info
->bytepos
= bidi_it
->bytepos
;
1024 saved_info
->type
= bidi_it
->type
;
1025 bidi_check_type (bidi_it
->type
);
1026 saved_info
->type_after_w1
= bidi_it
->type_after_w1
;
1027 bidi_check_type (bidi_it
->type_after_w1
);
1028 saved_info
->orig_type
= bidi_it
->orig_type
;
1029 bidi_check_type (bidi_it
->orig_type
);
1032 /* Resolve the type of a neutral character according to the type of
1033 surrounding strong text and the current embedding level. */
1034 static inline bidi_type_t
1035 bidi_resolve_neutral_1 (bidi_type_t prev_type
, bidi_type_t next_type
, int lev
)
1037 /* N1: European and Arabic numbers are treated as though they were R. */
1038 if (next_type
== WEAK_EN
|| next_type
== WEAK_AN
)
1039 next_type
= STRONG_R
;
1040 if (prev_type
== WEAK_EN
|| prev_type
== WEAK_AN
)
1041 prev_type
= STRONG_R
;
1043 if (next_type
== prev_type
) /* N1 */
1045 else if ((lev
& 1) == 0) /* N2 */
1052 bidi_explicit_dir_char (int c
)
1054 /* FIXME: this should be replaced with a lookup table with suitable
1055 bits set, like standard C ctype macros do. */
1056 return (c
== LRE_CHAR
|| c
== LRO_CHAR
1057 || c
== RLE_CHAR
|| c
== RLO_CHAR
|| c
== PDF_CHAR
);
1060 /* A helper function for bidi_resolve_explicit. It advances to the
1061 next character in logical order and determines the new embedding
1062 level and directional override, but does not take into account
1063 empty embeddings. */
1065 bidi_resolve_explicit_1 (struct bidi_it
*bidi_it
)
1071 bidi_dir_t override
;
1073 if (bidi_it
->bytepos
< BEGV_BYTE
/* after reseat to BEGV? */
1074 || bidi_it
->first_elt
)
1076 bidi_it
->first_elt
= 0;
1077 if (bidi_it
->charpos
< BEGV
)
1078 bidi_it
->charpos
= BEGV
;
1079 bidi_it
->bytepos
= CHAR_TO_BYTE (bidi_it
->charpos
);
1081 else if (bidi_it
->bytepos
< ZV_BYTE
) /* don't move at ZV */
1084 if (bidi_it
->ch_len
== 0)
1086 bidi_it
->bytepos
+= bidi_it
->ch_len
;
1089 current_level
= bidi_it
->level_stack
[bidi_it
->stack_idx
].level
; /* X1 */
1090 override
= bidi_it
->level_stack
[bidi_it
->stack_idx
].override
;
1091 new_level
= current_level
;
1093 /* in case it is a unibyte character (not yet implemented) */
1094 /* _fetch_multibyte_char_len = 1; */
1095 if (bidi_it
->bytepos
>= ZV_BYTE
)
1098 bidi_it
->ch_len
= 1;
1102 curchar
= FETCH_CHAR (bidi_it
->bytepos
);
1103 bidi_it
->ch_len
= CHAR_BYTES (curchar
);
1105 bidi_it
->ch
= curchar
;
1107 /* Don't apply directional override here, as all the types we handle
1108 below will not be affected by the override anyway, and we need
1109 the original type unaltered. The override will be applied in
1110 bidi_resolve_weak. */
1111 type
= bidi_get_type (curchar
, NEUTRAL_DIR
);
1112 bidi_it
->orig_type
= type
;
1113 bidi_check_type (bidi_it
->orig_type
);
1116 bidi_it
->prev_was_pdf
= 0;
1118 bidi_it
->type_after_w1
= UNKNOWN_BT
;
1124 bidi_it
->type_after_w1
= type
;
1125 bidi_check_type (bidi_it
->type_after_w1
);
1126 type
= WEAK_BN
; /* X9/Retaining */
1127 if (bidi_it
->ignore_bn_limit
<= 0)
1129 if (current_level
<= BIDI_MAXLEVEL
- 4)
1131 /* Compute the least odd embedding level greater than
1132 the current level. */
1133 new_level
= ((current_level
+ 1) & ~1) + 1;
1134 if (bidi_it
->type_after_w1
== RLE
)
1135 override
= NEUTRAL_DIR
;
1138 if (current_level
== BIDI_MAXLEVEL
- 4)
1139 bidi_it
->invalid_rl_levels
= 0;
1140 bidi_push_embedding_level (bidi_it
, new_level
, override
);
1144 bidi_it
->invalid_levels
++;
1145 /* See the commentary about invalid_rl_levels below. */
1146 if (bidi_it
->invalid_rl_levels
< 0)
1147 bidi_it
->invalid_rl_levels
= 0;
1148 bidi_it
->invalid_rl_levels
++;
1151 else if (bidi_it
->prev
.type_after_w1
== WEAK_EN
/* W5/Retaining */
1152 || bidi_it
->next_en_pos
> bidi_it
->charpos
)
1157 bidi_it
->type_after_w1
= type
;
1158 bidi_check_type (bidi_it
->type_after_w1
);
1159 type
= WEAK_BN
; /* X9/Retaining */
1160 if (bidi_it
->ignore_bn_limit
<= 0)
1162 if (current_level
<= BIDI_MAXLEVEL
- 5)
1164 /* Compute the least even embedding level greater than
1165 the current level. */
1166 new_level
= ((current_level
+ 2) & ~1);
1167 if (bidi_it
->type_after_w1
== LRE
)
1168 override
= NEUTRAL_DIR
;
1171 bidi_push_embedding_level (bidi_it
, new_level
, override
);
1175 bidi_it
->invalid_levels
++;
1176 /* invalid_rl_levels counts invalid levels encountered
1177 while the embedding level was already too high for
1178 LRE/LRO, but not for RLE/RLO. That is because
1179 there may be exactly one PDF which we should not
1180 ignore even though invalid_levels is non-zero.
1181 invalid_rl_levels helps to know what PDF is
1183 if (bidi_it
->invalid_rl_levels
>= 0)
1184 bidi_it
->invalid_rl_levels
++;
1187 else if (bidi_it
->prev
.type_after_w1
== WEAK_EN
/* W5/Retaining */
1188 || bidi_it
->next_en_pos
> bidi_it
->charpos
)
1192 bidi_it
->type_after_w1
= type
;
1193 bidi_check_type (bidi_it
->type_after_w1
);
1194 type
= WEAK_BN
; /* X9/Retaining */
1195 if (bidi_it
->ignore_bn_limit
<= 0)
1197 if (!bidi_it
->invalid_rl_levels
)
1199 new_level
= bidi_pop_embedding_level (bidi_it
);
1200 bidi_it
->invalid_rl_levels
= -1;
1201 if (bidi_it
->invalid_levels
)
1202 bidi_it
->invalid_levels
--;
1203 /* else nothing: UAX#9 says to ignore invalid PDFs */
1205 if (!bidi_it
->invalid_levels
)
1206 new_level
= bidi_pop_embedding_level (bidi_it
);
1209 bidi_it
->invalid_levels
--;
1210 bidi_it
->invalid_rl_levels
--;
1213 else if (bidi_it
->prev
.type_after_w1
== WEAK_EN
/* W5/Retaining */
1214 || bidi_it
->next_en_pos
> bidi_it
->charpos
)
1222 bidi_it
->type
= type
;
1223 bidi_check_type (bidi_it
->type
);
1228 /* Given an iterator state in BIDI_IT, advance one character position
1229 in the buffer to the next character (in the logical order), resolve
1230 any explicit embeddings and directional overrides, and return the
1231 embedding level of the character after resolving explicit
1232 directives and ignoring empty embeddings. */
1234 bidi_resolve_explicit (struct bidi_it
*bidi_it
)
1236 int prev_level
= bidi_it
->level_stack
[bidi_it
->stack_idx
].level
;
1237 int new_level
= bidi_resolve_explicit_1 (bidi_it
);
1239 if (prev_level
< new_level
1240 && bidi_it
->type
== WEAK_BN
1241 && bidi_it
->ignore_bn_limit
== 0 /* only if not already known */
1242 && bidi_it
->ch
!= BIDI_EOB
/* not already at EOB */
1243 && bidi_explicit_dir_char (FETCH_CHAR (bidi_it
->bytepos
1244 + bidi_it
->ch_len
)))
1246 /* Avoid pushing and popping embedding levels if the level run
1247 is empty, as this breaks level runs where it shouldn't.
1248 UAX#9 removes all the explicit embedding and override codes,
1249 so empty embeddings disappear without a trace. We need to
1250 behave as if we did the same. */
1251 struct bidi_it saved_it
;
1252 int level
= prev_level
;
1254 bidi_copy_it (&saved_it
, bidi_it
);
1256 while (bidi_explicit_dir_char (FETCH_CHAR (bidi_it
->bytepos
1257 + bidi_it
->ch_len
)))
1259 level
= bidi_resolve_explicit_1 (bidi_it
);
1262 if (level
== prev_level
) /* empty embedding */
1263 saved_it
.ignore_bn_limit
= bidi_it
->charpos
+ 1;
1264 else /* this embedding is non-empty */
1265 saved_it
.ignore_bn_limit
= -1;
1267 bidi_copy_it (bidi_it
, &saved_it
);
1268 if (bidi_it
->ignore_bn_limit
> 0)
1270 /* We pushed a level, but we shouldn't have. Undo that. */
1271 if (!bidi_it
->invalid_rl_levels
)
1273 new_level
= bidi_pop_embedding_level (bidi_it
);
1274 bidi_it
->invalid_rl_levels
= -1;
1275 if (bidi_it
->invalid_levels
)
1276 bidi_it
->invalid_levels
--;
1278 if (!bidi_it
->invalid_levels
)
1279 new_level
= bidi_pop_embedding_level (bidi_it
);
1282 bidi_it
->invalid_levels
--;
1283 bidi_it
->invalid_rl_levels
--;
1288 if (bidi_it
->type
== NEUTRAL_B
) /* X8 */
1290 bidi_set_paragraph_end (bidi_it
);
1291 /* This is needed by bidi_resolve_weak below, and in L1. */
1292 bidi_it
->type_after_w1
= bidi_it
->type
;
1293 bidi_check_type (bidi_it
->type_after_w1
);
1299 /* Advance in the buffer, resolve weak types and return the type of
1300 the next character after weak type resolution. */
1302 bidi_resolve_weak (struct bidi_it
*bidi_it
)
1305 bidi_dir_t override
;
1306 int prev_level
= bidi_it
->level_stack
[bidi_it
->stack_idx
].level
;
1307 int new_level
= bidi_resolve_explicit (bidi_it
);
1309 bidi_type_t type_of_next
;
1310 struct bidi_it saved_it
;
1312 type
= bidi_it
->type
;
1313 override
= bidi_it
->level_stack
[bidi_it
->stack_idx
].override
;
1315 if (type
== UNKNOWN_BT
1323 if (new_level
!= prev_level
1324 || bidi_it
->type
== NEUTRAL_B
)
1326 /* We've got a new embedding level run, compute the directional
1327 type of sor and initialize per-run variables (UAX#9, clause
1329 bidi_set_sor_type (bidi_it
, prev_level
, new_level
);
1331 else if (type
== NEUTRAL_S
|| type
== NEUTRAL_WS
1332 || type
== WEAK_BN
|| type
== STRONG_AL
)
1333 bidi_it
->type_after_w1
= type
; /* needed in L1 */
1334 bidi_check_type (bidi_it
->type_after_w1
);
1336 /* Level and directional override status are already recorded in
1337 bidi_it, and do not need any change; see X6. */
1338 if (override
== R2L
) /* X6 */
1340 else if (override
== L2R
)
1344 if (type
== WEAK_NSM
) /* W1 */
1346 /* Note that we don't need to consider the case where the
1347 prev character has its type overridden by an RLO or LRO:
1348 such characters are outside the current level run, and
1349 thus not relevant to this NSM. Thus, NSM gets the
1350 orig_type of the previous character. */
1351 if (bidi_it
->prev
.type
!= UNKNOWN_BT
)
1352 type
= bidi_it
->prev
.orig_type
;
1353 else if (bidi_it
->sor
== R2L
)
1355 else if (bidi_it
->sor
== L2R
)
1357 else /* shouldn't happen! */
1360 if (type
== WEAK_EN
/* W2 */
1361 && bidi_it
->last_strong
.type_after_w1
== STRONG_AL
)
1363 else if (type
== STRONG_AL
) /* W3 */
1365 else if ((type
== WEAK_ES
/* W4 */
1366 && bidi_it
->prev
.type_after_w1
== WEAK_EN
1367 && bidi_it
->prev
.orig_type
== WEAK_EN
)
1369 && ((bidi_it
->prev
.type_after_w1
== WEAK_EN
1370 && bidi_it
->prev
.orig_type
== WEAK_EN
)
1371 || bidi_it
->prev
.type_after_w1
== WEAK_AN
)))
1374 bidi_it
->bytepos
+ bidi_it
->ch_len
>= ZV_BYTE
1375 ? BIDI_EOB
: FETCH_CHAR (bidi_it
->bytepos
+ bidi_it
->ch_len
);
1376 type_of_next
= bidi_get_type (next_char
, override
);
1378 if (type_of_next
== WEAK_BN
1379 || bidi_explicit_dir_char (next_char
))
1381 bidi_copy_it (&saved_it
, bidi_it
);
1382 while (bidi_resolve_explicit (bidi_it
) == new_level
1383 && bidi_it
->type
== WEAK_BN
)
1385 type_of_next
= bidi_it
->type
;
1386 bidi_copy_it (bidi_it
, &saved_it
);
1389 /* If the next character is EN, but the last strong-type
1390 character is AL, that next EN will be changed to AN when
1391 we process it in W2 above. So in that case, this ES
1392 should not be changed into EN. */
1394 && type_of_next
== WEAK_EN
1395 && bidi_it
->last_strong
.type_after_w1
!= STRONG_AL
)
1397 else if (type
== WEAK_CS
)
1399 if (bidi_it
->prev
.type_after_w1
== WEAK_AN
1400 && (type_of_next
== WEAK_AN
1401 /* If the next character is EN, but the last
1402 strong-type character is AL, EN will be later
1403 changed to AN when we process it in W2 above.
1404 So in that case, this ES should not be
1406 || (type_of_next
== WEAK_EN
1407 && bidi_it
->last_strong
.type_after_w1
== STRONG_AL
)))
1409 else if (bidi_it
->prev
.type_after_w1
== WEAK_EN
1410 && type_of_next
== WEAK_EN
1411 && bidi_it
->last_strong
.type_after_w1
!= STRONG_AL
)
1415 else if (type
== WEAK_ET
/* W5: ET with EN before or after it */
1416 || type
== WEAK_BN
) /* W5/Retaining */
1418 if (bidi_it
->prev
.type_after_w1
== WEAK_EN
/* ET/BN w/EN before it */
1419 || bidi_it
->next_en_pos
> bidi_it
->charpos
)
1421 else /* W5: ET/BN with EN after it. */
1423 EMACS_INT en_pos
= bidi_it
->charpos
+ 1;
1426 bidi_it
->bytepos
+ bidi_it
->ch_len
>= ZV_BYTE
1427 ? BIDI_EOB
: FETCH_CHAR (bidi_it
->bytepos
+ bidi_it
->ch_len
);
1428 type_of_next
= bidi_get_type (next_char
, override
);
1430 if (type_of_next
== WEAK_ET
1431 || type_of_next
== WEAK_BN
1432 || bidi_explicit_dir_char (next_char
))
1434 bidi_copy_it (&saved_it
, bidi_it
);
1435 while (bidi_resolve_explicit (bidi_it
) == new_level
1436 && (bidi_it
->type
== WEAK_BN
1437 || bidi_it
->type
== WEAK_ET
))
1439 type_of_next
= bidi_it
->type
;
1440 en_pos
= bidi_it
->charpos
;
1441 bidi_copy_it (bidi_it
, &saved_it
);
1443 if (type_of_next
== WEAK_EN
)
1445 /* If the last strong character is AL, the EN we've
1446 found will become AN when we get to it (W2). */
1447 if (bidi_it
->last_strong
.type_after_w1
!= STRONG_AL
)
1450 /* Remember this EN position, to speed up processing
1452 bidi_it
->next_en_pos
= en_pos
;
1454 else if (type
== WEAK_BN
)
1455 type
= NEUTRAL_ON
; /* W6/Retaining */
1461 if (type
== WEAK_ES
|| type
== WEAK_ET
|| type
== WEAK_CS
/* W6 */
1463 && (bidi_it
->prev
.type_after_w1
== WEAK_CS
/* W6/Retaining */
1464 || bidi_it
->prev
.type_after_w1
== WEAK_ES
1465 || bidi_it
->prev
.type_after_w1
== WEAK_ET
)))
1468 /* Store the type we've got so far, before we clobber it with strong
1469 types in W7 and while resolving neutral types. But leave alone
1470 the original types that were recorded above, because we will need
1471 them for the L1 clause. */
1472 if (bidi_it
->type_after_w1
== UNKNOWN_BT
)
1473 bidi_it
->type_after_w1
= type
;
1474 bidi_check_type (bidi_it
->type_after_w1
);
1476 if (type
== WEAK_EN
) /* W7 */
1478 if ((bidi_it
->last_strong
.type_after_w1
== STRONG_L
)
1479 || (bidi_it
->last_strong
.type
== UNKNOWN_BT
&& bidi_it
->sor
== L2R
))
1483 bidi_it
->type
= type
;
1484 bidi_check_type (bidi_it
->type
);
1489 bidi_resolve_neutral (struct bidi_it
*bidi_it
)
1491 int prev_level
= bidi_it
->level_stack
[bidi_it
->stack_idx
].level
;
1492 bidi_type_t type
= bidi_resolve_weak (bidi_it
);
1493 int current_level
= bidi_it
->level_stack
[bidi_it
->stack_idx
].level
;
1495 if (!(type
== STRONG_R
1500 || type
== NEUTRAL_B
1501 || type
== NEUTRAL_S
1502 || type
== NEUTRAL_WS
1503 || type
== NEUTRAL_ON
))
1506 if (bidi_get_category (type
) == NEUTRAL
1507 || (type
== WEAK_BN
&& prev_level
== current_level
))
1509 if (bidi_it
->next_for_neutral
.type
!= UNKNOWN_BT
)
1510 type
= bidi_resolve_neutral_1 (bidi_it
->prev_for_neutral
.type
,
1511 bidi_it
->next_for_neutral
.type
,
1515 /* Arrrgh!! The UAX#9 algorithm is too deeply entrenched in
1516 the assumption of batch-style processing; see clauses W4,
1517 W5, and especially N1, which require to look far forward
1518 (as well as back) in the buffer. May the fleas of a
1519 thousand camels infest the armpits of those who design
1520 supposedly general-purpose algorithms by looking at their
1521 own implementations, and fail to consider other possible
1523 struct bidi_it saved_it
;
1524 bidi_type_t next_type
;
1526 if (bidi_it
->scan_dir
== -1)
1529 bidi_copy_it (&saved_it
, bidi_it
);
1530 /* Scan the text forward until we find the first non-neutral
1531 character, and then use that to resolve the neutral we
1532 are dealing with now. We also cache the scanned iterator
1533 states, to salvage some of the effort later. */
1534 bidi_cache_iterator_state (bidi_it
, 0);
1536 /* Record the info about the previous character, so that
1537 it will be cached below with this state. */
1538 if (bidi_it
->type_after_w1
!= WEAK_BN
/* W1/Retaining */
1539 && bidi_it
->type
!= WEAK_BN
)
1540 bidi_remember_char (&bidi_it
->prev
, bidi_it
);
1541 type
= bidi_resolve_weak (bidi_it
);
1542 /* Paragraph separators have their levels fully resolved
1543 at this point, so cache them as resolved. */
1544 bidi_cache_iterator_state (bidi_it
, type
== NEUTRAL_B
);
1545 /* FIXME: implement L1 here, by testing for a newline and
1546 resetting the level for any sequence of whitespace
1547 characters adjacent to it. */
1548 } while (!(type
== NEUTRAL_B
1550 && bidi_get_category (type
) != NEUTRAL
)
1551 /* This is all per level run, so stop when we
1552 reach the end of this level run. */
1553 || bidi_it
->level_stack
[bidi_it
->stack_idx
].level
!=
1556 bidi_remember_char (&saved_it
.next_for_neutral
, bidi_it
);
1567 /* N1: ``European and Arabic numbers are treated as
1568 though they were R.'' */
1569 next_type
= STRONG_R
;
1570 saved_it
.next_for_neutral
.type
= STRONG_R
;
1573 if (!bidi_explicit_dir_char (bidi_it
->ch
))
1574 abort (); /* can't happen: BNs are skipped */
1577 /* Marched all the way to the end of this level run.
1578 We need to use the eor type, whose information is
1579 stored by bidi_set_sor_type in the prev_for_neutral
1581 if (saved_it
.type
!= WEAK_BN
1582 || bidi_get_category (bidi_it
->prev
.type_after_w1
) == NEUTRAL
)
1584 next_type
= bidi_it
->prev_for_neutral
.type
;
1585 saved_it
.next_for_neutral
.type
= next_type
;
1586 bidi_check_type (next_type
);
1590 /* This is a BN which does not adjoin neutrals.
1591 Leave its type alone. */
1592 bidi_copy_it (bidi_it
, &saved_it
);
1593 return bidi_it
->type
;
1599 type
= bidi_resolve_neutral_1 (saved_it
.prev_for_neutral
.type
,
1600 next_type
, current_level
);
1601 saved_it
.type
= type
;
1602 bidi_check_type (type
);
1603 bidi_copy_it (bidi_it
, &saved_it
);
1609 /* Given an iterator state in BIDI_IT, advance one character position
1610 in the buffer to the next character (in the logical order), resolve
1611 the bidi type of that next character, and return that type. */
1613 bidi_type_of_next_char (struct bidi_it
*bidi_it
)
1617 /* This should always be called during a forward scan. */
1618 if (bidi_it
->scan_dir
!= 1)
1621 /* Reset the limit until which to ignore BNs if we step out of the
1622 area where we found only empty levels. */
1623 if ((bidi_it
->ignore_bn_limit
> 0
1624 && bidi_it
->ignore_bn_limit
<= bidi_it
->charpos
)
1625 || (bidi_it
->ignore_bn_limit
== -1
1626 && !bidi_explicit_dir_char (bidi_it
->ch
)))
1627 bidi_it
->ignore_bn_limit
= 0;
1629 type
= bidi_resolve_neutral (bidi_it
);
1634 /* Given an iterator state BIDI_IT, advance one character position in
1635 the buffer to the next character (in the logical order), resolve
1636 the embedding and implicit levels of that next character, and
1637 return the resulting level. */
1639 bidi_level_of_next_char (struct bidi_it
*bidi_it
)
1642 int level
, prev_level
= -1;
1643 struct bidi_saved_info next_for_neutral
;
1645 if (bidi_it
->scan_dir
== 1)
1647 /* There's no sense in trying to advance if we hit end of text. */
1648 if (bidi_it
->ch
== BIDI_EOB
)
1649 return bidi_it
->resolved_level
;
1651 /* Record the info about the previous character. */
1652 if (bidi_it
->type_after_w1
!= WEAK_BN
/* W1/Retaining */
1653 && bidi_it
->type
!= WEAK_BN
)
1654 bidi_remember_char (&bidi_it
->prev
, bidi_it
);
1655 if (bidi_it
->type_after_w1
== STRONG_R
1656 || bidi_it
->type_after_w1
== STRONG_L
1657 || bidi_it
->type_after_w1
== STRONG_AL
)
1658 bidi_remember_char (&bidi_it
->last_strong
, bidi_it
);
1659 /* FIXME: it sounds like we don't need both prev and
1660 prev_for_neutral members, but I'm leaving them both for now. */
1661 if (bidi_it
->type
== STRONG_R
|| bidi_it
->type
== STRONG_L
1662 || bidi_it
->type
== WEAK_EN
|| bidi_it
->type
== WEAK_AN
)
1663 bidi_remember_char (&bidi_it
->prev_for_neutral
, bidi_it
);
1665 /* If we overstepped the characters used for resolving neutrals
1666 and whitespace, invalidate their info in the iterator. */
1667 if (bidi_it
->charpos
>= bidi_it
->next_for_neutral
.charpos
)
1668 bidi_it
->next_for_neutral
.type
= UNKNOWN_BT
;
1669 if (bidi_it
->next_en_pos
>= 0
1670 && bidi_it
->charpos
>= bidi_it
->next_en_pos
)
1671 bidi_it
->next_en_pos
= -1;
1672 if (bidi_it
->next_for_ws
.type
!= UNKNOWN_BT
1673 && bidi_it
->charpos
>= bidi_it
->next_for_ws
.charpos
)
1674 bidi_it
->next_for_ws
.type
= UNKNOWN_BT
;
1676 /* This must be taken before we fill the iterator with the info
1677 about the next char. If we scan backwards, the iterator
1678 state must be already cached, so there's no need to know the
1679 embedding level of the previous character, since we will be
1680 returning to our caller shortly. */
1681 prev_level
= bidi_it
->level_stack
[bidi_it
->stack_idx
].level
;
1683 next_for_neutral
= bidi_it
->next_for_neutral
;
1685 /* Perhaps it is already cached. */
1686 type
= bidi_cache_find (bidi_it
->charpos
+ bidi_it
->scan_dir
, -1, bidi_it
);
1687 if (type
!= UNKNOWN_BT
)
1689 /* Don't lose the information for resolving neutrals! The
1690 cached states could have been cached before their
1691 next_for_neutral member was computed. If we are on our way
1692 forward, we can simply take the info from the previous
1694 if (bidi_it
->scan_dir
== 1
1695 && bidi_it
->next_for_neutral
.type
== UNKNOWN_BT
)
1696 bidi_it
->next_for_neutral
= next_for_neutral
;
1698 /* If resolved_level is -1, it means this state was cached
1699 before it was completely resolved, so we cannot return
1701 if (bidi_it
->resolved_level
!= -1)
1702 return bidi_it
->resolved_level
;
1704 if (bidi_it
->scan_dir
== -1)
1705 /* If we are going backwards, the iterator state is already cached
1706 from previous scans, and should be fully resolved. */
1709 if (type
== UNKNOWN_BT
)
1710 type
= bidi_type_of_next_char (bidi_it
);
1712 if (type
== NEUTRAL_B
)
1713 return bidi_it
->resolved_level
;
1715 level
= bidi_it
->level_stack
[bidi_it
->stack_idx
].level
;
1716 if ((bidi_get_category (type
) == NEUTRAL
/* && type != NEUTRAL_B */)
1717 || (type
== WEAK_BN
&& prev_level
== level
))
1719 if (bidi_it
->next_for_neutral
.type
== UNKNOWN_BT
)
1722 /* If the cached state shows a neutral character, it was not
1723 resolved by bidi_resolve_neutral, so do it now. */
1724 type
= bidi_resolve_neutral_1 (bidi_it
->prev_for_neutral
.type
,
1725 bidi_it
->next_for_neutral
.type
,
1729 if (!(type
== STRONG_R
1733 || type
== WEAK_AN
))
1735 bidi_it
->type
= type
;
1736 bidi_check_type (bidi_it
->type
);
1738 /* For L1 below, we need to know, for each WS character, whether
1739 it belongs to a sequence of WS characters preceeding a newline
1740 or a TAB or a paragraph separator. */
1741 if (bidi_it
->orig_type
== NEUTRAL_WS
1742 && bidi_it
->next_for_ws
.type
== UNKNOWN_BT
)
1745 int clen
= bidi_it
->ch_len
;
1746 EMACS_INT bpos
= bidi_it
->bytepos
;
1747 EMACS_INT cpos
= bidi_it
->charpos
;
1751 /*_fetch_multibyte_char_len = 1;*/
1752 ch
= bpos
+ clen
>= ZV_BYTE
? BIDI_EOB
: FETCH_CHAR (bpos
+ clen
);
1755 clen
= (ch
== BIDI_EOB
? 1 : CHAR_BYTES (ch
));
1756 if (ch
== '\n' || ch
== BIDI_EOB
/* || ch == LINESEP_CHAR */)
1759 chtype
= bidi_get_type (ch
, NEUTRAL_DIR
);
1760 } while (chtype
== NEUTRAL_WS
|| chtype
== WEAK_BN
1761 || bidi_explicit_dir_char (ch
)); /* L1/Retaining */
1762 bidi_it
->next_for_ws
.type
= chtype
;
1763 bidi_check_type (bidi_it
->next_for_ws
.type
);
1764 bidi_it
->next_for_ws
.charpos
= cpos
;
1765 bidi_it
->next_for_ws
.bytepos
= bpos
;
1768 /* Resolve implicit levels, with a twist: PDFs get the embedding
1769 level of the enbedding they terminate. See below for the
1771 if (bidi_it
->orig_type
== PDF
1772 /* Don't do this if this formatting code didn't change the
1773 embedding level due to invalid or empty embeddings. */
1774 && prev_level
!= level
)
1776 /* Don't look in UAX#9 for the reason for this: it's our own
1777 private quirk. The reason is that we want the formatting
1778 codes to be delivered so that they bracket the text of their
1779 embedding. For example, given the text
1783 we want it to be displayed as
1791 which will result because we bump up the embedding level as
1792 soon as we see the RLO and pop it as soon as we see the PDF,
1793 so RLO itself has the same embedding level as "teST", and
1794 thus would be normally delivered last, just before the PDF.
1795 The switch below fiddles with the level of PDF so that this
1796 ugly side effect does not happen.
1798 (This is, of course, only important if the formatting codes
1799 are actually displayed, but Emacs does need to display them
1800 if the user wants to.) */
1803 else if (bidi_it
->orig_type
== NEUTRAL_B
/* L1 */
1804 || bidi_it
->orig_type
== NEUTRAL_S
1805 || bidi_it
->ch
== '\n' || bidi_it
->ch
== BIDI_EOB
1806 /* || bidi_it->ch == LINESEP_CHAR */
1807 || (bidi_it
->orig_type
== NEUTRAL_WS
1808 && (bidi_it
->next_for_ws
.type
== NEUTRAL_B
1809 || bidi_it
->next_for_ws
.type
== NEUTRAL_S
)))
1810 level
= bidi_it
->level_stack
[0].level
;
1811 else if ((level
& 1) == 0) /* I1 */
1813 if (type
== STRONG_R
)
1815 else if (type
== WEAK_EN
|| type
== WEAK_AN
)
1820 if (type
== STRONG_L
|| type
== WEAK_EN
|| type
== WEAK_AN
)
1824 bidi_it
->resolved_level
= level
;
1828 /* Move to the other edge of a level given by LEVEL. If END_FLAG is
1829 non-zero, we are at the end of a level, and we need to prepare to
1830 resume the scan of the lower level.
1832 If this level's other edge is cached, we simply jump to it, filling
1833 the iterator structure with the iterator state on the other edge.
1834 Otherwise, we walk the buffer until we come back to the same level
1837 Note: we are not talking here about a ``level run'' in the UAX#9
1838 sense of the term, but rather about a ``level'' which includes
1839 all the levels higher than it. In other words, given the levels
1842 11111112222222333333334443343222222111111112223322111
1845 and assuming we are at point A scanning left to right, this
1846 function moves to point C, whereas the UAX#9 ``level 2 run'' ends
1849 bidi_find_other_level_edge (struct bidi_it
*bidi_it
, int level
, int end_flag
)
1851 int dir
= end_flag
? -bidi_it
->scan_dir
: bidi_it
->scan_dir
;
1854 /* Try the cache first. */
1855 if ((idx
= bidi_cache_find_level_change (level
, dir
, end_flag
)) >= 0)
1856 bidi_cache_fetch_state (idx
, bidi_it
);
1862 abort (); /* if we are at end of level, its edges must be cached */
1864 bidi_cache_iterator_state (bidi_it
, 1);
1866 new_level
= bidi_level_of_next_char (bidi_it
);
1867 bidi_cache_iterator_state (bidi_it
, 1);
1868 } while (new_level
>= level
);
1873 bidi_get_next_char_visually (struct bidi_it
*bidi_it
)
1875 int old_level
, new_level
, next_level
;
1876 struct bidi_it sentinel
;
1878 if (bidi_it
->scan_dir
== 0)
1880 bidi_it
->scan_dir
= 1; /* default to logical order */
1883 /* If we just passed a newline, initialize for the next line. */
1884 if (!bidi_it
->first_elt
&& bidi_it
->orig_type
== NEUTRAL_B
)
1885 bidi_line_init (bidi_it
);
1887 /* Prepare the sentinel iterator state. */
1888 if (bidi_cache_idx
== 0)
1890 bidi_copy_it (&sentinel
, bidi_it
);
1891 if (bidi_it
->first_elt
)
1893 sentinel
.charpos
--; /* cached charpos needs to be monotonic */
1895 sentinel
.ch
= '\n'; /* doesn't matter, but why not? */
1896 sentinel
.ch_len
= 1;
1900 old_level
= bidi_it
->resolved_level
;
1901 new_level
= bidi_level_of_next_char (bidi_it
);
1903 /* Reordering of resolved levels (clause L2) is implemented by
1904 jumping to the other edge of the level and flipping direction of
1905 scanning the buffer whenever we find a level change. */
1906 if (new_level
!= old_level
)
1908 int ascending
= new_level
> old_level
;
1909 int level_to_search
= ascending
? old_level
+ 1 : old_level
;
1910 int incr
= ascending
? 1 : -1;
1911 int expected_next_level
= old_level
+ incr
;
1913 /* If we don't have anything cached yet, we need to cache the
1914 sentinel state, since we'll need it to record where to jump
1915 when the last non-base level is exhausted. */
1916 if (bidi_cache_idx
== 0)
1917 bidi_cache_iterator_state (&sentinel
, 1);
1918 /* Jump (or walk) to the other edge of this level. */
1919 bidi_find_other_level_edge (bidi_it
, level_to_search
, !ascending
);
1920 /* Switch scan direction and peek at the next character in the
1922 bidi_it
->scan_dir
= -bidi_it
->scan_dir
;
1924 /* The following loop handles the case where the resolved level
1925 jumps by more than one. This is typical for numbers inside a
1926 run of text with left-to-right embedding direction, but can
1927 also happen in other situations. In those cases the decision
1928 where to continue after a level change, and in what direction,
1929 is tricky. For example, given a text like below:
1934 (where the numbers below the text show the resolved levels),
1935 the result of reordering according to UAX#9 should be this:
1939 This is implemented by the loop below which flips direction
1940 and jumps to the other edge of the level each time it finds
1941 the new level not to be the expected one. The expected level
1942 is always one more or one less than the previous one. */
1943 next_level
= bidi_peek_at_next_level (bidi_it
);
1944 while (next_level
!= expected_next_level
)
1946 expected_next_level
+= incr
;
1947 level_to_search
+= incr
;
1948 bidi_find_other_level_edge (bidi_it
, level_to_search
, !ascending
);
1949 bidi_it
->scan_dir
= -bidi_it
->scan_dir
;
1950 next_level
= bidi_peek_at_next_level (bidi_it
);
1953 /* Finally, deliver the next character in the new direction. */
1954 next_level
= bidi_level_of_next_char (bidi_it
);
1957 /* Take note when we have just processed the newline that precedes
1958 the end of the paragraph. The next time we are about to be
1959 called, set_iterator_to_next will automatically reinit the
1960 paragraph direction, if needed. We do this at the newline before
1961 the paragraph separator, because the next character might not be
1962 the first character of the next paragraph, due to the bidi
1964 if (bidi_it
->scan_dir
== 1
1965 && bidi_it
->orig_type
== NEUTRAL_B
1966 && bidi_it
->bytepos
< ZV_BYTE
)
1969 bidi_at_paragraph_end (bidi_it
->charpos
+ 1,
1970 bidi_it
->bytepos
+ bidi_it
->ch_len
);
1973 bidi_it
->new_paragraph
= 1;
1974 /* Record the buffer position of the last character of the
1975 paragraph separator. */
1976 bidi_it
->separator_limit
= bidi_it
->charpos
+ 1 + sep_len
;
1980 if (bidi_it
->scan_dir
== 1 && bidi_cache_idx
)
1982 /* If we are at paragraph's base embedding level and beyond the
1983 last cached position, the cache's job is done and we can
1985 if (bidi_it
->resolved_level
== bidi_it
->level_stack
[0].level
1986 && bidi_it
->charpos
> bidi_cache
[bidi_cache_idx
- 1].charpos
)
1987 bidi_cache_reset ();
1988 /* But as long as we are caching during forward scan, we must
1989 cache each state, or else the cache integrity will be
1990 compromised: it assumes cached states correspond to buffer
1993 bidi_cache_iterator_state (bidi_it
, 1);
1997 /* This is meant to be called from within the debugger, whenever you
1998 wish to examine the cache contents. */
2000 bidi_dump_cached_states (void)
2005 if (bidi_cache_idx
== 0)
2007 fprintf (stderr
, "The cache is empty.\n");
2010 fprintf (stderr
, "Total of %d state%s in cache:\n",
2011 bidi_cache_idx
, bidi_cache_idx
== 1 ? "" : "s");
2013 for (i
= bidi_cache
[bidi_cache_idx
- 1].charpos
; i
> 0; i
/= 10)
2015 fputs ("ch ", stderr
);
2016 for (i
= 0; i
< bidi_cache_idx
; i
++)
2017 fprintf (stderr
, "%*c", ndigits
, bidi_cache
[i
].ch
);
2018 fputs ("\n", stderr
);
2019 fputs ("lvl ", stderr
);
2020 for (i
= 0; i
< bidi_cache_idx
; i
++)
2021 fprintf (stderr
, "%*d", ndigits
, bidi_cache
[i
].resolved_level
);
2022 fputs ("\n", stderr
);
2023 fputs ("pos ", stderr
);
2024 for (i
= 0; i
< bidi_cache_idx
; i
++)
2025 fprintf (stderr
, "%*d", ndigits
, bidi_cache
[i
].charpos
);
2026 fputs ("\n", stderr
);