Commit | Line | Data |
---|---|---|
b7b65b15 | 1 | /* Low-level bidirectional buffer-scanning functions for GNU Emacs. |
b118e65f EZ |
2 | Copyright (C) 2000, 2001, 2004, 2005, 2009, 2010 |
3 | Free Software Foundation, Inc. | |
b7b65b15 EZ |
4 | |
5 | This file is part of GNU Emacs. | |
6 | ||
a8d11bd3 | 7 | GNU Emacs is free software: you can redistribute it and/or modify |
b7b65b15 | 8 | it under the terms of the GNU General Public License as published by |
a8d11bd3 EZ |
9 | the Free Software Foundation, either version 3 of the License, or |
10 | (at your option) any later version. | |
b7b65b15 EZ |
11 | |
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. | |
16 | ||
b7b65b15 | 17 | You should have received a copy of the GNU General Public License |
a8d11bd3 | 18 | along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. */ |
b7b65b15 | 19 | |
2d6e4628 EZ |
20 | /* Written by Eli Zaretskii <eliz@gnu.org>. |
21 | ||
22 | A sequential implementation of the Unicode Bidirectional algorithm, | |
b7b65b15 EZ |
23 | as per UAX#9, a part of the Unicode Standard. |
24 | ||
25 | Unlike the reference and most other implementations, this one is | |
940afb59 EZ |
26 | designed to be called once for every character in the buffer or |
27 | string. | |
b7b65b15 | 28 | |
4b292a22 | 29 | The main entry point is bidi_move_to_visually_next. Each time it |
b7b65b15 EZ |
30 | is called, it finds the next character in the visual order, and |
31 | returns its information in a special structure. The caller is then | |
32 | expected to process this character for display or any other | |
4b292a22 EZ |
33 | purposes, and call bidi_move_to_visually_next for the next |
34 | character. See the comments in bidi_move_to_visually_next for more | |
35 | details about its algorithm that finds the next visual-order | |
b7b65b15 EZ |
36 | character by resolving their levels on the fly. |
37 | ||
940afb59 EZ |
38 | The two other entry points are bidi_paragraph_init and |
39 | bidi_mirror_char. The first determines the base direction of a | |
40 | paragraph, while the second returns the mirrored version of its | |
41 | argument character. | |
42 | ||
89d3374a EZ |
43 | If you want to understand the code, you will have to read it |
44 | together with the relevant portions of UAX#9. The comments include | |
45 | references to UAX#9 rules, for that very reason. | |
46 | ||
b7b65b15 EZ |
47 | A note about references to UAX#9 rules: if the reference says |
48 | something like "X9/Retaining", it means that you need to refer to | |
49 | rule X9 and to its modifications decribed in the "Implementation | |
50 | Notes" section of UAX#9, under "Retaining Format Codes". */ | |
51 | ||
52 | #ifdef HAVE_CONFIG_H | |
53 | #include <config.h> | |
54 | #endif | |
55 | ||
56 | #include <stdio.h> | |
57 | ||
58 | #ifdef HAVE_STRING_H | |
59 | #include <string.h> | |
60 | #endif | |
61 | ||
29e3d8d1 EZ |
62 | #include <setjmp.h> |
63 | ||
b7b65b15 EZ |
64 | #include "lisp.h" |
65 | #include "buffer.h" | |
66 | #include "character.h" | |
67 | #include "dispextern.h" | |
68 | ||
69 | static int bidi_initialized = 0; | |
70 | ||
71 | static Lisp_Object bidi_type_table; | |
72 | ||
e7402cb2 | 73 | /* FIXME: Remove these when bidi_explicit_dir_char uses a lookup table. */ |
b7b65b15 EZ |
74 | #define LRM_CHAR 0x200E |
75 | #define RLM_CHAR 0x200F | |
76 | #define LRE_CHAR 0x202A | |
77 | #define RLE_CHAR 0x202B | |
78 | #define PDF_CHAR 0x202C | |
79 | #define LRO_CHAR 0x202D | |
80 | #define RLO_CHAR 0x202E | |
81 | ||
b7b65b15 | 82 | #define BIDI_EOB -1 |
e7402cb2 | 83 | #define BIDI_BOB -2 /* FIXME: Is this needed? */ |
b7b65b15 | 84 | |
b7b65b15 EZ |
85 | /* Local data structures. (Look in dispextern.h for the rest.) */ |
86 | ||
87 | /* What we need to know about the current paragraph. */ | |
88 | struct bidi_paragraph_info { | |
89 | int start_bytepos; /* byte position where it begins */ | |
90 | int end_bytepos; /* byte position where it ends */ | |
91 | int embedding_level; /* its basic embedding level */ | |
92 | bidi_dir_t base_dir; /* its base direction */ | |
93 | }; | |
94 | ||
95 | /* Data type for describing the bidirectional character categories. */ | |
96 | typedef enum { | |
97 | UNKNOWN_BC, | |
98 | NEUTRAL, | |
99 | WEAK, | |
100 | STRONG | |
101 | } bidi_category_t; | |
102 | ||
103 | int bidi_ignore_explicit_marks_for_paragraph_level = 1; | |
104 | ||
372b7a95 | 105 | static Lisp_Object paragraph_start_re, paragraph_separate_re; |
6bff6497 | 106 | static Lisp_Object Qparagraph_start, Qparagraph_separate; |
b7b65b15 | 107 | |
b7b65b15 EZ |
108 | static void |
109 | bidi_initialize () | |
110 | { | |
317fbf33 EZ |
111 | |
112 | #include "biditype.h" | |
113 | ||
b7b65b15 EZ |
114 | int i; |
115 | ||
116 | bidi_type_table = Fmake_char_table (Qnil, make_number (STRONG_L)); | |
2d6e4628 | 117 | staticpro (&bidi_type_table); |
b7b65b15 EZ |
118 | |
119 | for (i = 0; i < sizeof bidi_type / sizeof bidi_type[0]; i++) | |
317fbf33 | 120 | char_table_set_range (bidi_type_table, bidi_type[i].from, bidi_type[i].to, |
b7b65b15 | 121 | make_number (bidi_type[i].type)); |
6bff6497 | 122 | |
b4bf28b7 SM |
123 | Qparagraph_start = intern ("paragraph-start"); |
124 | staticpro (&Qparagraph_start); | |
372b7a95 EZ |
125 | paragraph_start_re = Fsymbol_value (Qparagraph_start); |
126 | if (!STRINGP (paragraph_start_re)) | |
127 | paragraph_start_re = build_string ("\f\\|[ \t]*$"); | |
128 | staticpro (¶graph_start_re); | |
b4bf28b7 SM |
129 | Qparagraph_separate = intern ("paragraph-separate"); |
130 | staticpro (&Qparagraph_separate); | |
372b7a95 EZ |
131 | paragraph_separate_re = Fsymbol_value (Qparagraph_separate); |
132 | if (!STRINGP (paragraph_separate_re)) | |
133 | paragraph_separate_re = build_string ("[ \t\f]*$"); | |
134 | staticpro (¶graph_separate_re); | |
b7b65b15 EZ |
135 | bidi_initialized = 1; |
136 | } | |
137 | ||
6bff6497 EZ |
138 | /* Return the bidi type of a character CH, subject to the current |
139 | directional OVERRIDE. */ | |
fd3998ff | 140 | static INLINE bidi_type_t |
6bff6497 | 141 | bidi_get_type (int ch, bidi_dir_t override) |
b7b65b15 | 142 | { |
6bff6497 EZ |
143 | bidi_type_t default_type; |
144 | ||
e7402cb2 EZ |
145 | if (ch == BIDI_EOB) |
146 | return NEUTRAL_B; | |
e342a24d EZ |
147 | if (ch < 0 || ch > MAX_CHAR) |
148 | abort (); | |
6bff6497 EZ |
149 | |
150 | default_type = (bidi_type_t) XINT (CHAR_TABLE_REF (bidi_type_table, ch)); | |
151 | ||
152 | if (override == NEUTRAL_DIR) | |
153 | return default_type; | |
154 | ||
155 | switch (default_type) | |
156 | { | |
157 | /* Although UAX#9 does not tell, it doesn't make sense to | |
158 | override NEUTRAL_B and LRM/RLM characters. */ | |
159 | case NEUTRAL_B: | |
160 | case LRE: | |
161 | case LRO: | |
162 | case RLE: | |
163 | case RLO: | |
164 | case PDF: | |
165 | return default_type; | |
166 | default: | |
167 | switch (ch) | |
168 | { | |
169 | case LRM_CHAR: | |
170 | case RLM_CHAR: | |
171 | return default_type; | |
172 | default: | |
173 | if (override == L2R) /* X6 */ | |
174 | return STRONG_L; | |
175 | else if (override == R2L) | |
176 | return STRONG_R; | |
177 | else | |
178 | abort (); /* can't happen: handled above */ | |
179 | } | |
180 | } | |
b7b65b15 EZ |
181 | } |
182 | ||
2d6e4628 EZ |
183 | void |
184 | bidi_check_type (bidi_type_t type) | |
185 | { | |
186 | if (type < UNKNOWN_BT || type > NEUTRAL_ON) | |
187 | abort (); | |
188 | } | |
189 | ||
b7b65b15 | 190 | /* Given a bidi TYPE of a character, return its category. */ |
fd3998ff | 191 | static INLINE bidi_category_t |
b7b65b15 EZ |
192 | bidi_get_category (bidi_type_t type) |
193 | { | |
194 | switch (type) | |
195 | { | |
196 | case UNKNOWN_BT: | |
197 | return UNKNOWN_BC; | |
198 | case STRONG_L: | |
199 | case STRONG_R: | |
200 | case STRONG_AL: | |
201 | case LRE: | |
202 | case LRO: | |
203 | case RLE: | |
204 | case RLO: | |
205 | return STRONG; | |
206 | case PDF: /* ??? really?? */ | |
207 | case WEAK_EN: | |
208 | case WEAK_ES: | |
209 | case WEAK_ET: | |
210 | case WEAK_AN: | |
211 | case WEAK_CS: | |
212 | case WEAK_NSM: | |
213 | case WEAK_BN: | |
214 | return WEAK; | |
215 | case NEUTRAL_B: | |
216 | case NEUTRAL_S: | |
217 | case NEUTRAL_WS: | |
218 | case NEUTRAL_ON: | |
219 | return NEUTRAL; | |
220 | default: | |
221 | abort (); | |
222 | } | |
223 | } | |
224 | ||
e342a24d EZ |
225 | /* Return the mirrored character of C, if any. |
226 | ||
227 | Note: The conditions in UAX#9 clause L4 must be tested by the | |
228 | caller. */ | |
b7b65b15 EZ |
229 | /* FIXME: exceedingly temporary! Should consult the Unicode database |
230 | of character properties. */ | |
231 | int | |
232 | bidi_mirror_char (int c) | |
233 | { | |
234 | static const char mirrored_pairs[] = "()<>[]{}"; | |
9443b3c7 | 235 | const char *p = c > 0 && c < 128 ? strchr (mirrored_pairs, c) : NULL; |
b7b65b15 EZ |
236 | |
237 | if (p) | |
238 | { | |
239 | size_t i = p - mirrored_pairs; | |
240 | ||
9443b3c7 | 241 | return mirrored_pairs [(i ^ 1)]; |
b7b65b15 EZ |
242 | } |
243 | return c; | |
244 | } | |
245 | ||
246 | /* Copy the bidi iterator from FROM to TO. To save cycles, this only | |
247 | copies the part of the level stack that is actually in use. */ | |
fd3998ff | 248 | static INLINE void |
b7b65b15 EZ |
249 | bidi_copy_it (struct bidi_it *to, struct bidi_it *from) |
250 | { | |
251 | int i; | |
252 | ||
e69a9370 EZ |
253 | /* Copy everything except the level stack and beyond. */ |
254 | memcpy (to, from, ((size_t)&((struct bidi_it *)0)->level_stack[0])); | |
b7b65b15 EZ |
255 | |
256 | /* Copy the active part of the level stack. */ | |
257 | to->level_stack[0] = from->level_stack[0]; /* level zero is always in use */ | |
258 | for (i = 1; i <= from->stack_idx; i++) | |
259 | to->level_stack[i] = from->level_stack[i]; | |
260 | } | |
261 | ||
262 | /* Caching the bidi iterator states. */ | |
263 | ||
2fe72643 EZ |
264 | #define BIDI_CACHE_CHUNK 200 |
265 | static struct bidi_it *bidi_cache; | |
266 | static size_t bidi_cache_size = 0; | |
0416466c | 267 | static size_t elsz = sizeof (struct bidi_it); |
2fe72643 EZ |
268 | static int bidi_cache_idx; /* next unused cache slot */ |
269 | static int bidi_cache_last_idx; /* slot of last cache hit */ | |
b7b65b15 | 270 | |
fd3998ff | 271 | static INLINE void |
b7b65b15 EZ |
272 | bidi_cache_reset (void) |
273 | { | |
274 | bidi_cache_idx = 0; | |
275 | bidi_cache_last_idx = -1; | |
276 | } | |
277 | ||
2fe72643 EZ |
278 | static INLINE void |
279 | bidi_cache_shrink (void) | |
280 | { | |
281 | if (bidi_cache_size > BIDI_CACHE_CHUNK) | |
282 | { | |
0416466c EZ |
283 | bidi_cache_size = BIDI_CACHE_CHUNK; |
284 | bidi_cache = | |
285 | (struct bidi_it *) xrealloc (bidi_cache, bidi_cache_size * elsz); | |
2fe72643 EZ |
286 | } |
287 | bidi_cache_reset (); | |
288 | } | |
289 | ||
fd3998ff | 290 | static INLINE void |
b7b65b15 EZ |
291 | bidi_cache_fetch_state (int idx, struct bidi_it *bidi_it) |
292 | { | |
293 | int current_scan_dir = bidi_it->scan_dir; | |
294 | ||
295 | if (idx < 0 || idx >= bidi_cache_idx) | |
296 | abort (); | |
297 | ||
298 | bidi_copy_it (bidi_it, &bidi_cache[idx]); | |
299 | bidi_it->scan_dir = current_scan_dir; | |
300 | bidi_cache_last_idx = idx; | |
301 | } | |
302 | ||
303 | /* Find a cached state with a given CHARPOS and resolved embedding | |
304 | level less or equal to LEVEL. if LEVEL is -1, disregard the | |
305 | resolved levels in cached states. DIR, if non-zero, means search | |
306 | in that direction from the last cache hit. */ | |
fd3998ff | 307 | static INLINE int |
b7b65b15 EZ |
308 | bidi_cache_search (int charpos, int level, int dir) |
309 | { | |
310 | int i, i_start; | |
311 | ||
312 | if (bidi_cache_idx) | |
313 | { | |
314 | if (charpos < bidi_cache[bidi_cache_last_idx].charpos) | |
315 | dir = -1; | |
316 | else if (charpos > bidi_cache[bidi_cache_last_idx].charpos) | |
317 | dir = 1; | |
318 | if (dir) | |
319 | i_start = bidi_cache_last_idx; | |
320 | else | |
321 | { | |
322 | dir = -1; | |
323 | i_start = bidi_cache_idx - 1; | |
324 | } | |
325 | ||
326 | if (dir < 0) | |
327 | { | |
328 | /* Linear search for now; FIXME! */ | |
329 | for (i = i_start; i >= 0; i--) | |
330 | if (bidi_cache[i].charpos == charpos | |
331 | && (level == -1 || bidi_cache[i].resolved_level <= level)) | |
332 | return i; | |
333 | } | |
334 | else | |
335 | { | |
336 | for (i = i_start; i < bidi_cache_idx; i++) | |
337 | if (bidi_cache[i].charpos == charpos | |
338 | && (level == -1 || bidi_cache[i].resolved_level <= level)) | |
339 | return i; | |
340 | } | |
341 | } | |
342 | ||
343 | return -1; | |
344 | } | |
345 | ||
346 | /* Find a cached state where the resolved level changes to a value | |
347 | that is lower than LEVEL, and return its cache slot index. DIR is | |
348 | the direction to search, starting with the last used cache slot. | |
349 | BEFORE, if non-zero, means return the index of the slot that is | |
350 | ``before'' the level change in the search direction. That is, | |
351 | given the cached levels like this: | |
352 | ||
353 | 1122333442211 | |
354 | AB C | |
355 | ||
356 | and assuming we are at the position cached at the slot marked with | |
357 | C, searching backwards (DIR = -1) for LEVEL = 2 will return the | |
358 | index of slot B or A, depending whether BEFORE is, respectively, | |
359 | non-zero or zero. */ | |
360 | static int | |
361 | bidi_cache_find_level_change (int level, int dir, int before) | |
362 | { | |
363 | if (bidi_cache_idx) | |
364 | { | |
365 | int i = dir ? bidi_cache_last_idx : bidi_cache_idx - 1; | |
366 | int incr = before ? 1 : 0; | |
367 | ||
368 | if (!dir) | |
369 | dir = -1; | |
370 | else if (!incr) | |
371 | i += dir; | |
372 | ||
373 | if (dir < 0) | |
374 | { | |
375 | while (i >= incr) | |
376 | { | |
377 | if (bidi_cache[i - incr].resolved_level >= 0 | |
378 | && bidi_cache[i - incr].resolved_level < level) | |
379 | return i; | |
380 | i--; | |
381 | } | |
382 | } | |
383 | else | |
384 | { | |
385 | while (i < bidi_cache_idx - incr) | |
386 | { | |
387 | if (bidi_cache[i + incr].resolved_level >= 0 | |
388 | && bidi_cache[i + incr].resolved_level < level) | |
389 | return i; | |
390 | i++; | |
391 | } | |
392 | } | |
393 | } | |
394 | ||
395 | return -1; | |
396 | } | |
397 | ||
fd3998ff | 398 | static INLINE void |
b7b65b15 EZ |
399 | bidi_cache_iterator_state (struct bidi_it *bidi_it, int resolved) |
400 | { | |
401 | int idx; | |
402 | ||
403 | /* We should never cache on backward scans. */ | |
404 | if (bidi_it->scan_dir == -1) | |
405 | abort (); | |
406 | idx = bidi_cache_search (bidi_it->charpos, -1, 1); | |
407 | ||
408 | if (idx < 0) | |
409 | { | |
410 | idx = bidi_cache_idx; | |
2fe72643 EZ |
411 | /* Enlarge the cache as needed. */ |
412 | if (idx >= bidi_cache_size) | |
413 | { | |
0416466c | 414 | bidi_cache_size += BIDI_CACHE_CHUNK; |
2fe72643 | 415 | bidi_cache = |
0416466c | 416 | (struct bidi_it *) xrealloc (bidi_cache, bidi_cache_size * elsz); |
2fe72643 | 417 | } |
bd924a5d EZ |
418 | /* Character positions should correspond to cache positions 1:1. |
419 | If we are outside the range of cached positions, the cache is | |
420 | useless and must be reset. */ | |
421 | if (idx > 0 && | |
422 | (bidi_it->charpos > bidi_cache[idx - 1].charpos + 1 | |
423 | || bidi_it->charpos < bidi_cache[0].charpos)) | |
424 | { | |
425 | bidi_cache_reset (); | |
426 | idx = 0; | |
427 | } | |
b7b65b15 EZ |
428 | bidi_copy_it (&bidi_cache[idx], bidi_it); |
429 | if (!resolved) | |
430 | bidi_cache[idx].resolved_level = -1; | |
431 | } | |
432 | else | |
433 | { | |
434 | /* Copy only the members which could have changed, to avoid | |
435 | costly copying of the entire struct. */ | |
436 | bidi_cache[idx].type = bidi_it->type; | |
2d6e4628 | 437 | bidi_check_type (bidi_it->type); |
89d3374a EZ |
438 | bidi_cache[idx].type_after_w1 = bidi_it->type_after_w1; |
439 | bidi_check_type (bidi_it->type_after_w1); | |
b7b65b15 EZ |
440 | if (resolved) |
441 | bidi_cache[idx].resolved_level = bidi_it->resolved_level; | |
442 | else | |
443 | bidi_cache[idx].resolved_level = -1; | |
444 | bidi_cache[idx].invalid_levels = bidi_it->invalid_levels; | |
445 | bidi_cache[idx].invalid_rl_levels = bidi_it->invalid_rl_levels; | |
446 | bidi_cache[idx].next_for_neutral = bidi_it->next_for_neutral; | |
447 | bidi_cache[idx].next_for_ws = bidi_it->next_for_ws; | |
448 | bidi_cache[idx].ignore_bn_limit = bidi_it->ignore_bn_limit; | |
449 | } | |
450 | ||
451 | bidi_cache_last_idx = idx; | |
452 | if (idx >= bidi_cache_idx) | |
453 | bidi_cache_idx = idx + 1; | |
454 | } | |
455 | ||
fd3998ff | 456 | static INLINE bidi_type_t |
b7b65b15 EZ |
457 | bidi_cache_find (int charpos, int level, struct bidi_it *bidi_it) |
458 | { | |
459 | int i = bidi_cache_search (charpos, level, bidi_it->scan_dir); | |
460 | ||
461 | if (i >= 0) | |
462 | { | |
463 | bidi_dir_t current_scan_dir = bidi_it->scan_dir; | |
464 | ||
5009f85e | 465 | bidi_copy_it (bidi_it, &bidi_cache[i]); |
b7b65b15 EZ |
466 | bidi_cache_last_idx = i; |
467 | /* Don't let scan direction from from the cached state override | |
468 | the current scan direction. */ | |
469 | bidi_it->scan_dir = current_scan_dir; | |
470 | return bidi_it->type; | |
471 | } | |
472 | ||
473 | return UNKNOWN_BT; | |
474 | } | |
475 | ||
fd3998ff | 476 | static INLINE int |
b7b65b15 EZ |
477 | bidi_peek_at_next_level (struct bidi_it *bidi_it) |
478 | { | |
479 | if (bidi_cache_idx == 0 || bidi_cache_last_idx == -1) | |
480 | abort (); | |
481 | return bidi_cache[bidi_cache_last_idx + bidi_it->scan_dir].resolved_level; | |
482 | } | |
483 | ||
be39f003 EZ |
484 | /* Check if buffer position CHARPOS/BYTEPOS is the end of a paragraph. |
485 | Value is the non-negative length of the paragraph separator | |
486 | following the buffer position, -1 if position is at the beginning | |
487 | of a new paragraph, or -2 if position is neither at beginning nor | |
488 | at end of a paragraph. */ | |
fd3998ff | 489 | static EMACS_INT |
6bff6497 | 490 | bidi_at_paragraph_end (EMACS_INT charpos, EMACS_INT bytepos) |
b7b65b15 | 491 | { |
b4bf28b7 | 492 | /* FIXME: Why Fbuffer_local_value rather than just Fsymbol_value? */ |
372b7a95 EZ |
493 | Lisp_Object sep_re; |
494 | Lisp_Object start_re; | |
be39f003 EZ |
495 | EMACS_INT val; |
496 | ||
372b7a95 EZ |
497 | sep_re = paragraph_separate_re; |
498 | start_re = paragraph_start_re; | |
be39f003 EZ |
499 | |
500 | val = fast_looking_at (sep_re, charpos, bytepos, ZV, ZV_BYTE, Qnil); | |
501 | if (val < 0) | |
502 | { | |
503 | if (fast_looking_at (start_re, charpos, bytepos, ZV, ZV_BYTE, Qnil) >= 0) | |
504 | val = -1; | |
505 | else | |
506 | val = -2; | |
507 | } | |
b7b65b15 | 508 | |
be39f003 | 509 | return val; |
b7b65b15 EZ |
510 | } |
511 | ||
512 | /* Determine the start-of-run (sor) directional type given the two | |
513 | embedding levels on either side of the run boundary. Also, update | |
514 | the saved info about previously seen characters, since that info is | |
515 | generally valid for a single level run. */ | |
fd3998ff | 516 | static INLINE void |
b7b65b15 EZ |
517 | bidi_set_sor_type (struct bidi_it *bidi_it, int level_before, int level_after) |
518 | { | |
519 | int higher_level = level_before > level_after ? level_before : level_after; | |
520 | ||
521 | /* The prev_was_pdf gork is required for when we have several PDFs | |
522 | in a row. In that case, we want to compute the sor type for the | |
523 | next level run only once: when we see the first PDF. That's | |
524 | because the sor type depends only on the higher of the two levels | |
525 | that we find on the two sides of the level boundary (see UAX#9, | |
526 | clause X10), and so we don't need to know the final embedding | |
527 | level to which we descend after processing all the PDFs. */ | |
e342a24d | 528 | if (!bidi_it->prev_was_pdf || level_before < level_after) |
b7b65b15 EZ |
529 | /* FIXME: should the default sor direction be user selectable? */ |
530 | bidi_it->sor = (higher_level & 1) != 0 ? R2L : L2R; | |
531 | if (level_before > level_after) | |
532 | bidi_it->prev_was_pdf = 1; | |
533 | ||
534 | bidi_it->prev.type = UNKNOWN_BT; | |
89d3374a EZ |
535 | bidi_it->last_strong.type = bidi_it->last_strong.type_after_w1 = |
536 | bidi_it->last_strong.orig_type = UNKNOWN_BT; | |
b7b65b15 EZ |
537 | bidi_it->prev_for_neutral.type = bidi_it->sor == R2L ? STRONG_R : STRONG_L; |
538 | bidi_it->prev_for_neutral.charpos = bidi_it->charpos; | |
539 | bidi_it->prev_for_neutral.bytepos = bidi_it->bytepos; | |
89d3374a EZ |
540 | bidi_it->next_for_neutral.type = bidi_it->next_for_neutral.type_after_w1 = |
541 | bidi_it->next_for_neutral.orig_type = UNKNOWN_BT; | |
b7b65b15 EZ |
542 | bidi_it->ignore_bn_limit = 0; /* meaning it's unknown */ |
543 | } | |
544 | ||
6bff6497 | 545 | static void |
be39f003 EZ |
546 | bidi_line_init (struct bidi_it *bidi_it) |
547 | { | |
548 | bidi_it->scan_dir = 1; /* FIXME: do we need to have control on this? */ | |
549 | bidi_it->resolved_level = bidi_it->level_stack[0].level; | |
550 | bidi_it->level_stack[0].override = NEUTRAL_DIR; /* X1 */ | |
551 | bidi_it->invalid_levels = 0; | |
552 | bidi_it->invalid_rl_levels = -1; | |
553 | bidi_it->next_en_pos = -1; | |
554 | bidi_it->next_for_ws.type = UNKNOWN_BT; | |
b44d9321 EZ |
555 | bidi_set_sor_type (bidi_it, |
556 | bidi_it->paragraph_dir == R2L ? 1 : 0, | |
be39f003 EZ |
557 | bidi_it->level_stack[0].level); /* X10 */ |
558 | ||
559 | bidi_cache_reset (); | |
560 | } | |
561 | ||
562 | /* Find the beginning of this paragraph by looking back in the buffer. | |
563 | Value is the byte position of the paragraph's beginning. */ | |
564 | static EMACS_INT | |
b44d9321 | 565 | bidi_find_paragraph_start (EMACS_INT pos, EMACS_INT pos_byte) |
6bff6497 | 566 | { |
372b7a95 | 567 | Lisp_Object re = paragraph_start_re; |
6bff6497 EZ |
568 | EMACS_INT limit = ZV, limit_byte = ZV_BYTE; |
569 | ||
6bff6497 EZ |
570 | while (pos_byte > BEGV_BYTE |
571 | && fast_looking_at (re, pos, pos_byte, limit, limit_byte, Qnil) < 0) | |
572 | { | |
be39f003 EZ |
573 | pos = find_next_newline_no_quit (pos - 1, -1); |
574 | pos_byte = CHAR_TO_BYTE (pos); | |
6bff6497 | 575 | } |
be39f003 | 576 | return pos_byte; |
6bff6497 EZ |
577 | } |
578 | ||
be39f003 | 579 | /* Determine the direction, a.k.a. base embedding level, of the |
b44d9321 EZ |
580 | paragraph we are about to iterate through. If DIR is either L2R or |
581 | R2L, just use that. Otherwise, determine the paragraph direction | |
582 | from the first strong character of the paragraph. | |
583 | ||
584 | Note that this gives the paragraph separator the same direction as | |
585 | the preceding paragraph, even though Emacs generally views the | |
586 | separartor as not belonging to any paragraph. */ | |
b7b65b15 EZ |
587 | void |
588 | bidi_paragraph_init (bidi_dir_t dir, struct bidi_it *bidi_it) | |
589 | { | |
6bff6497 | 590 | EMACS_INT bytepos = bidi_it->bytepos; |
e7402cb2 | 591 | |
5e65aec0 EZ |
592 | /* Special case for an empty buffer. */ |
593 | if (bytepos == BEGV_BYTE && bytepos == ZV_BYTE) | |
594 | dir = L2R; | |
9c82e145 | 595 | /* We should never be called at EOB or before BEGV. */ |
5e65aec0 | 596 | else if (bytepos >= ZV_BYTE || bytepos < BEGV_BYTE) |
9c82e145 EZ |
597 | abort (); |
598 | ||
be39f003 EZ |
599 | if (dir == L2R) |
600 | { | |
601 | bidi_it->paragraph_dir = L2R; | |
602 | bidi_it->new_paragraph = 0; | |
603 | } | |
604 | else if (dir == R2L) | |
605 | { | |
606 | bidi_it->paragraph_dir = R2L; | |
607 | bidi_it->new_paragraph = 0; | |
608 | } | |
b7b65b15 EZ |
609 | else if (dir == NEUTRAL_DIR) /* P2 */ |
610 | { | |
6bff6497 EZ |
611 | int ch, ch_len; |
612 | EMACS_INT pos; | |
613 | bidi_type_t type; | |
be39f003 | 614 | |
d20e1419 EZ |
615 | if (!bidi_initialized) |
616 | bidi_initialize (); | |
617 | ||
be39f003 EZ |
618 | /* If we are inside a paragraph separator, we are just waiting |
619 | for the separator to be exhausted; use the previous paragraph | |
e5a2fec7 EZ |
620 | direction. But don't do that if we have been just reseated, |
621 | because we need to reinitialize below in that case. */ | |
622 | if (!bidi_it->first_elt | |
623 | && bidi_it->charpos < bidi_it->separator_limit) | |
be39f003 EZ |
624 | return; |
625 | ||
b44d9321 | 626 | /* If we are on a newline, get past it to where the next |
5e65aec0 EZ |
627 | paragraph might start. But don't do that at BEGV since then |
628 | we are potentially in a new paragraph that doesn't yet | |
629 | exist. */ | |
c143c213 | 630 | pos = bidi_it->charpos; |
5e65aec0 | 631 | if (bytepos > BEGV_BYTE && FETCH_CHAR (bytepos) == '\n') |
be39f003 | 632 | { |
b44d9321 | 633 | bytepos++; |
c143c213 | 634 | pos++; |
be39f003 | 635 | } |
b44d9321 EZ |
636 | |
637 | /* We are either at the beginning of a paragraph or in the | |
638 | middle of it. Find where this paragraph starts. */ | |
639 | bytepos = bidi_find_paragraph_start (pos, bytepos); | |
6bff6497 | 640 | |
be39f003 EZ |
641 | bidi_it->separator_limit = -1; |
642 | bidi_it->new_paragraph = 0; | |
6bff6497 EZ |
643 | ch = FETCH_CHAR (bytepos); |
644 | ch_len = CHAR_BYTES (ch); | |
be39f003 | 645 | pos = BYTE_TO_CHAR (bytepos); |
6bff6497 | 646 | type = bidi_get_type (ch, NEUTRAL_DIR); |
b7b65b15 | 647 | |
e342a24d | 648 | for (pos++, bytepos += ch_len; |
b7b65b15 EZ |
649 | /* NOTE: UAX#9 says to search only for L, AL, or R types of |
650 | characters, and ignore RLE, RLO, LRE, and LRO. However, | |
651 | I'm not sure it makes sense to omit those 4; should try | |
652 | with and without that to see the effect. */ | |
653 | (bidi_get_category (type) != STRONG) | |
654 | || (bidi_ignore_explicit_marks_for_paragraph_level | |
655 | && (type == RLE || type == RLO | |
656 | || type == LRE || type == LRO)); | |
6bff6497 | 657 | type = bidi_get_type (ch, NEUTRAL_DIR)) |
b7b65b15 | 658 | { |
be39f003 | 659 | if (type == NEUTRAL_B && bidi_at_paragraph_end (pos, bytepos) >= -1) |
b7b65b15 | 660 | break; |
21fce5ab EZ |
661 | if (bytepos >= ZV_BYTE) |
662 | { | |
663 | /* Pretend there's a paragraph separator at end of buffer. */ | |
664 | type = NEUTRAL_B; | |
665 | break; | |
666 | } | |
b7b65b15 EZ |
667 | FETCH_CHAR_ADVANCE (ch, pos, bytepos); |
668 | } | |
669 | if (type == STRONG_R || type == STRONG_AL) /* P3 */ | |
be39f003 EZ |
670 | bidi_it->paragraph_dir = R2L; |
671 | else if (type == STRONG_L) | |
672 | bidi_it->paragraph_dir = L2R; | |
b7b65b15 | 673 | } |
be39f003 EZ |
674 | else |
675 | abort (); | |
b7b65b15 | 676 | |
b44d9321 EZ |
677 | /* Contrary to UAX#9 clause P3, we only default the paragraph |
678 | direction to L2R if we have no previous usable paragraph | |
679 | direction. */ | |
d20e1419 | 680 | if (bidi_it->paragraph_dir != L2R && bidi_it->paragraph_dir != R2L) |
b44d9321 | 681 | bidi_it->paragraph_dir = L2R; /* P3 and ``higher protocols'' */ |
be39f003 | 682 | if (bidi_it->paragraph_dir == R2L) |
b44d9321 | 683 | bidi_it->level_stack[0].level = 1; |
be39f003 | 684 | else |
b44d9321 | 685 | bidi_it->level_stack[0].level = 0; |
be39f003 EZ |
686 | |
687 | bidi_line_init (bidi_it); | |
b7b65b15 EZ |
688 | } |
689 | ||
6bff6497 EZ |
690 | /* Do whatever UAX#9 clause X8 says should be done at paragraph's |
691 | end. */ | |
fd3998ff | 692 | static INLINE void |
b7b65b15 EZ |
693 | bidi_set_paragraph_end (struct bidi_it *bidi_it) |
694 | { | |
695 | bidi_it->invalid_levels = 0; | |
696 | bidi_it->invalid_rl_levels = -1; | |
697 | bidi_it->stack_idx = 0; | |
698 | bidi_it->resolved_level = bidi_it->level_stack[0].level; | |
b7b65b15 EZ |
699 | } |
700 | ||
89d3374a | 701 | /* Initialize the bidi iterator from buffer position CHARPOS. */ |
b7b65b15 | 702 | void |
6bff6497 | 703 | bidi_init_it (EMACS_INT charpos, EMACS_INT bytepos, struct bidi_it *bidi_it) |
b7b65b15 EZ |
704 | { |
705 | if (! bidi_initialized) | |
706 | bidi_initialize (); | |
89d3374a EZ |
707 | bidi_it->charpos = charpos; |
708 | bidi_it->bytepos = bytepos; | |
6bff6497 EZ |
709 | bidi_it->first_elt = 1; |
710 | bidi_set_paragraph_end (bidi_it); | |
711 | bidi_it->new_paragraph = 1; | |
be39f003 | 712 | bidi_it->separator_limit = -1; |
b7b65b15 | 713 | bidi_it->type = NEUTRAL_B; |
ebb5722e EZ |
714 | bidi_it->type_after_w1 = NEUTRAL_B; |
715 | bidi_it->orig_type = NEUTRAL_B; | |
b7b65b15 | 716 | bidi_it->prev_was_pdf = 0; |
ebb5722e EZ |
717 | bidi_it->prev.type = bidi_it->prev.type_after_w1 = |
718 | bidi_it->prev.orig_type = UNKNOWN_BT; | |
89d3374a EZ |
719 | bidi_it->last_strong.type = bidi_it->last_strong.type_after_w1 = |
720 | bidi_it->last_strong.orig_type = UNKNOWN_BT; | |
b7b65b15 EZ |
721 | bidi_it->next_for_neutral.charpos = -1; |
722 | bidi_it->next_for_neutral.type = | |
89d3374a EZ |
723 | bidi_it->next_for_neutral.type_after_w1 = |
724 | bidi_it->next_for_neutral.orig_type = UNKNOWN_BT; | |
b7b65b15 EZ |
725 | bidi_it->prev_for_neutral.charpos = -1; |
726 | bidi_it->prev_for_neutral.type = | |
89d3374a EZ |
727 | bidi_it->prev_for_neutral.type_after_w1 = |
728 | bidi_it->prev_for_neutral.orig_type = UNKNOWN_BT; | |
b7b65b15 | 729 | bidi_it->sor = L2R; /* FIXME: should it be user-selectable? */ |
2fe72643 | 730 | bidi_cache_shrink (); |
b7b65b15 EZ |
731 | } |
732 | ||
733 | /* Push the current embedding level and override status; reset the | |
734 | current level to LEVEL and the current override status to OVERRIDE. */ | |
fd3998ff | 735 | static INLINE void |
b7b65b15 EZ |
736 | bidi_push_embedding_level (struct bidi_it *bidi_it, |
737 | int level, bidi_dir_t override) | |
738 | { | |
739 | bidi_it->stack_idx++; | |
740 | if (bidi_it->stack_idx >= BIDI_MAXLEVEL) | |
741 | abort (); | |
742 | bidi_it->level_stack[bidi_it->stack_idx].level = level; | |
743 | bidi_it->level_stack[bidi_it->stack_idx].override = override; | |
744 | } | |
745 | ||
746 | /* Pop the embedding level and directional override status from the | |
747 | stack, and return the new level. */ | |
fd3998ff | 748 | static INLINE int |
b7b65b15 EZ |
749 | bidi_pop_embedding_level (struct bidi_it *bidi_it) |
750 | { | |
751 | /* UAX#9 says to ignore invalid PDFs. */ | |
752 | if (bidi_it->stack_idx > 0) | |
753 | bidi_it->stack_idx--; | |
754 | return bidi_it->level_stack[bidi_it->stack_idx].level; | |
755 | } | |
756 | ||
757 | /* Record in SAVED_INFO the information about the current character. */ | |
fd3998ff | 758 | static INLINE void |
b7b65b15 EZ |
759 | bidi_remember_char (struct bidi_saved_info *saved_info, |
760 | struct bidi_it *bidi_it) | |
761 | { | |
762 | saved_info->charpos = bidi_it->charpos; | |
763 | saved_info->bytepos = bidi_it->bytepos; | |
764 | saved_info->type = bidi_it->type; | |
2d6e4628 | 765 | bidi_check_type (bidi_it->type); |
89d3374a EZ |
766 | saved_info->type_after_w1 = bidi_it->type_after_w1; |
767 | bidi_check_type (bidi_it->type_after_w1); | |
b7b65b15 | 768 | saved_info->orig_type = bidi_it->orig_type; |
2d6e4628 | 769 | bidi_check_type (bidi_it->orig_type); |
b7b65b15 EZ |
770 | } |
771 | ||
772 | /* Resolve the type of a neutral character according to the type of | |
773 | surrounding strong text and the current embedding level. */ | |
fd3998ff | 774 | static INLINE bidi_type_t |
b7b65b15 EZ |
775 | bidi_resolve_neutral_1 (bidi_type_t prev_type, bidi_type_t next_type, int lev) |
776 | { | |
777 | /* N1: European and Arabic numbers are treated as though they were R. */ | |
778 | if (next_type == WEAK_EN || next_type == WEAK_AN) | |
779 | next_type = STRONG_R; | |
780 | if (prev_type == WEAK_EN || prev_type == WEAK_AN) | |
781 | prev_type = STRONG_R; | |
782 | ||
783 | if (next_type == prev_type) /* N1 */ | |
784 | return next_type; | |
785 | else if ((lev & 1) == 0) /* N2 */ | |
786 | return STRONG_L; | |
787 | else | |
788 | return STRONG_R; | |
789 | } | |
790 | ||
fd3998ff | 791 | static INLINE int |
b7b65b15 EZ |
792 | bidi_explicit_dir_char (int c) |
793 | { | |
794 | /* FIXME: this should be replaced with a lookup table with suitable | |
795 | bits set, like standard C ctype macros do. */ | |
796 | return (c == LRE_CHAR || c == LRO_CHAR | |
797 | || c == RLE_CHAR || c == RLO_CHAR || c == PDF_CHAR); | |
798 | } | |
799 | ||
800 | /* A helper function for bidi_resolve_explicit. It advances to the | |
801 | next character in logical order and determines the new embedding | |
802 | level and directional override, but does not take into account | |
803 | empty embeddings. */ | |
804 | static int | |
805 | bidi_resolve_explicit_1 (struct bidi_it *bidi_it) | |
806 | { | |
807 | int curchar; | |
808 | bidi_type_t type; | |
809 | int current_level; | |
810 | int new_level; | |
811 | bidi_dir_t override; | |
812 | ||
9c82e145 EZ |
813 | if (bidi_it->bytepos < BEGV_BYTE /* after reseat to BEGV? */ |
814 | || bidi_it->first_elt) | |
e7402cb2 | 815 | { |
9c82e145 EZ |
816 | bidi_it->first_elt = 0; |
817 | if (bidi_it->charpos < BEGV) | |
818 | bidi_it->charpos = BEGV; | |
819 | bidi_it->bytepos = CHAR_TO_BYTE (bidi_it->charpos); | |
e7402cb2 | 820 | } |
9c82e145 | 821 | else if (bidi_it->bytepos < ZV_BYTE) /* don't move at ZV */ |
b7b65b15 EZ |
822 | { |
823 | bidi_it->charpos++; | |
e7402cb2 EZ |
824 | if (bidi_it->ch_len == 0) |
825 | abort (); | |
b7b65b15 EZ |
826 | bidi_it->bytepos += bidi_it->ch_len; |
827 | } | |
828 | ||
829 | current_level = bidi_it->level_stack[bidi_it->stack_idx].level; /* X1 */ | |
830 | override = bidi_it->level_stack[bidi_it->stack_idx].override; | |
831 | new_level = current_level; | |
832 | ||
833 | /* in case it is a unibyte character (not yet implemented) */ | |
834 | /* _fetch_multibyte_char_len = 1; */ | |
e7402cb2 EZ |
835 | if (bidi_it->bytepos >= ZV_BYTE) |
836 | { | |
837 | curchar = BIDI_EOB; | |
838 | bidi_it->ch_len = 1; | |
839 | } | |
840 | else | |
841 | { | |
842 | curchar = FETCH_CHAR (bidi_it->bytepos); | |
843 | bidi_it->ch_len = CHAR_BYTES (curchar); | |
844 | } | |
b7b65b15 | 845 | bidi_it->ch = curchar; |
b7b65b15 | 846 | |
6bff6497 EZ |
847 | /* Don't apply directional override here, as all the types we handle |
848 | below will not be affected by the override anyway, and we need | |
849 | the original type unaltered. The override will be applied in | |
850 | bidi_resolve_weak. */ | |
851 | type = bidi_get_type (curchar, NEUTRAL_DIR); | |
89d3374a EZ |
852 | bidi_it->orig_type = type; |
853 | bidi_check_type (bidi_it->orig_type); | |
b7b65b15 EZ |
854 | |
855 | if (type != PDF) | |
856 | bidi_it->prev_was_pdf = 0; | |
857 | ||
89d3374a | 858 | bidi_it->type_after_w1 = UNKNOWN_BT; |
b7b65b15 EZ |
859 | |
860 | switch (type) | |
861 | { | |
862 | case RLE: /* X2 */ | |
863 | case RLO: /* X4 */ | |
89d3374a EZ |
864 | bidi_it->type_after_w1 = type; |
865 | bidi_check_type (bidi_it->type_after_w1); | |
b7b65b15 EZ |
866 | type = WEAK_BN; /* X9/Retaining */ |
867 | if (bidi_it->ignore_bn_limit <= 0) | |
868 | { | |
869 | if (current_level <= BIDI_MAXLEVEL - 4) | |
870 | { | |
871 | /* Compute the least odd embedding level greater than | |
872 | the current level. */ | |
873 | new_level = ((current_level + 1) & ~1) + 1; | |
89d3374a | 874 | if (bidi_it->type_after_w1 == RLE) |
b7b65b15 EZ |
875 | override = NEUTRAL_DIR; |
876 | else | |
877 | override = R2L; | |
878 | if (current_level == BIDI_MAXLEVEL - 4) | |
879 | bidi_it->invalid_rl_levels = 0; | |
880 | bidi_push_embedding_level (bidi_it, new_level, override); | |
881 | } | |
882 | else | |
883 | { | |
884 | bidi_it->invalid_levels++; | |
885 | /* See the commentary about invalid_rl_levels below. */ | |
886 | if (bidi_it->invalid_rl_levels < 0) | |
887 | bidi_it->invalid_rl_levels = 0; | |
888 | bidi_it->invalid_rl_levels++; | |
889 | } | |
890 | } | |
89d3374a | 891 | else if (bidi_it->prev.type_after_w1 == WEAK_EN /* W5/Retaining */ |
b7b65b15 EZ |
892 | || bidi_it->next_en_pos > bidi_it->charpos) |
893 | type = WEAK_EN; | |
894 | break; | |
895 | case LRE: /* X3 */ | |
896 | case LRO: /* X5 */ | |
89d3374a EZ |
897 | bidi_it->type_after_w1 = type; |
898 | bidi_check_type (bidi_it->type_after_w1); | |
b7b65b15 EZ |
899 | type = WEAK_BN; /* X9/Retaining */ |
900 | if (bidi_it->ignore_bn_limit <= 0) | |
901 | { | |
902 | if (current_level <= BIDI_MAXLEVEL - 5) | |
903 | { | |
904 | /* Compute the least even embedding level greater than | |
905 | the current level. */ | |
906 | new_level = ((current_level + 2) & ~1); | |
89d3374a | 907 | if (bidi_it->type_after_w1 == LRE) |
b7b65b15 EZ |
908 | override = NEUTRAL_DIR; |
909 | else | |
910 | override = L2R; | |
911 | bidi_push_embedding_level (bidi_it, new_level, override); | |
912 | } | |
913 | else | |
914 | { | |
915 | bidi_it->invalid_levels++; | |
916 | /* invalid_rl_levels counts invalid levels encountered | |
917 | while the embedding level was already too high for | |
918 | LRE/LRO, but not for RLE/RLO. That is because | |
919 | there may be exactly one PDF which we should not | |
920 | ignore even though invalid_levels is non-zero. | |
921 | invalid_rl_levels helps to know what PDF is | |
922 | that. */ | |
923 | if (bidi_it->invalid_rl_levels >= 0) | |
924 | bidi_it->invalid_rl_levels++; | |
925 | } | |
926 | } | |
89d3374a | 927 | else if (bidi_it->prev.type_after_w1 == WEAK_EN /* W5/Retaining */ |
b7b65b15 EZ |
928 | || bidi_it->next_en_pos > bidi_it->charpos) |
929 | type = WEAK_EN; | |
930 | break; | |
931 | case PDF: /* X7 */ | |
89d3374a EZ |
932 | bidi_it->type_after_w1 = type; |
933 | bidi_check_type (bidi_it->type_after_w1); | |
b7b65b15 EZ |
934 | type = WEAK_BN; /* X9/Retaining */ |
935 | if (bidi_it->ignore_bn_limit <= 0) | |
936 | { | |
937 | if (!bidi_it->invalid_rl_levels) | |
938 | { | |
939 | new_level = bidi_pop_embedding_level (bidi_it); | |
940 | bidi_it->invalid_rl_levels = -1; | |
941 | if (bidi_it->invalid_levels) | |
942 | bidi_it->invalid_levels--; | |
943 | /* else nothing: UAX#9 says to ignore invalid PDFs */ | |
944 | } | |
945 | if (!bidi_it->invalid_levels) | |
946 | new_level = bidi_pop_embedding_level (bidi_it); | |
947 | else | |
948 | { | |
949 | bidi_it->invalid_levels--; | |
950 | bidi_it->invalid_rl_levels--; | |
951 | } | |
952 | } | |
89d3374a | 953 | else if (bidi_it->prev.type_after_w1 == WEAK_EN /* W5/Retaining */ |
b7b65b15 EZ |
954 | || bidi_it->next_en_pos > bidi_it->charpos) |
955 | type = WEAK_EN; | |
956 | break; | |
957 | default: | |
958 | /* Nothing. */ | |
959 | break; | |
960 | } | |
961 | ||
962 | bidi_it->type = type; | |
2d6e4628 | 963 | bidi_check_type (bidi_it->type); |
b7b65b15 EZ |
964 | |
965 | return new_level; | |
966 | } | |
967 | ||
968 | /* Given an iterator state in BIDI_IT, advance one character position | |
969 | in the buffer to the next character (in the logical order), resolve | |
970 | any explicit embeddings and directional overrides, and return the | |
971 | embedding level of the character after resolving explicit | |
972 | directives and ignoring empty embeddings. */ | |
973 | static int | |
974 | bidi_resolve_explicit (struct bidi_it *bidi_it) | |
975 | { | |
976 | int prev_level = bidi_it->level_stack[bidi_it->stack_idx].level; | |
977 | int new_level = bidi_resolve_explicit_1 (bidi_it); | |
978 | ||
979 | if (prev_level < new_level | |
980 | && bidi_it->type == WEAK_BN | |
981 | && bidi_it->ignore_bn_limit == 0 /* only if not already known */ | |
1502b819 | 982 | && bidi_it->bytepos < ZV_BYTE /* not already at EOB */ |
b7b65b15 EZ |
983 | && bidi_explicit_dir_char (FETCH_CHAR (bidi_it->bytepos |
984 | + bidi_it->ch_len))) | |
985 | { | |
986 | /* Avoid pushing and popping embedding levels if the level run | |
987 | is empty, as this breaks level runs where it shouldn't. | |
988 | UAX#9 removes all the explicit embedding and override codes, | |
989 | so empty embeddings disappear without a trace. We need to | |
990 | behave as if we did the same. */ | |
991 | struct bidi_it saved_it; | |
992 | int level = prev_level; | |
993 | ||
994 | bidi_copy_it (&saved_it, bidi_it); | |
995 | ||
996 | while (bidi_explicit_dir_char (FETCH_CHAR (bidi_it->bytepos | |
997 | + bidi_it->ch_len))) | |
998 | { | |
999 | level = bidi_resolve_explicit_1 (bidi_it); | |
1000 | } | |
1001 | ||
1002 | if (level == prev_level) /* empty embedding */ | |
1003 | saved_it.ignore_bn_limit = bidi_it->charpos + 1; | |
1004 | else /* this embedding is non-empty */ | |
1005 | saved_it.ignore_bn_limit = -1; | |
1006 | ||
1007 | bidi_copy_it (bidi_it, &saved_it); | |
1008 | if (bidi_it->ignore_bn_limit > 0) | |
1009 | { | |
1010 | /* We pushed a level, but we shouldn't have. Undo that. */ | |
1011 | if (!bidi_it->invalid_rl_levels) | |
1012 | { | |
1013 | new_level = bidi_pop_embedding_level (bidi_it); | |
1014 | bidi_it->invalid_rl_levels = -1; | |
1015 | if (bidi_it->invalid_levels) | |
1016 | bidi_it->invalid_levels--; | |
1017 | } | |
1018 | if (!bidi_it->invalid_levels) | |
1019 | new_level = bidi_pop_embedding_level (bidi_it); | |
1020 | else | |
1021 | { | |
1022 | bidi_it->invalid_levels--; | |
1023 | bidi_it->invalid_rl_levels--; | |
1024 | } | |
1025 | } | |
1026 | } | |
1027 | ||
b7b65b15 EZ |
1028 | if (bidi_it->type == NEUTRAL_B) /* X8 */ |
1029 | { | |
21fce5ab | 1030 | bidi_set_paragraph_end (bidi_it); |
6bff6497 EZ |
1031 | /* This is needed by bidi_resolve_weak below, and in L1. */ |
1032 | bidi_it->type_after_w1 = bidi_it->type; | |
89d3374a | 1033 | bidi_check_type (bidi_it->type_after_w1); |
b7b65b15 EZ |
1034 | } |
1035 | ||
1036 | return new_level; | |
1037 | } | |
1038 | ||
1039 | /* Advance in the buffer, resolve weak types and return the type of | |
1040 | the next character after weak type resolution. */ | |
fd3998ff | 1041 | static bidi_type_t |
b7b65b15 EZ |
1042 | bidi_resolve_weak (struct bidi_it *bidi_it) |
1043 | { | |
1044 | bidi_type_t type; | |
1045 | bidi_dir_t override; | |
1046 | int prev_level = bidi_it->level_stack[bidi_it->stack_idx].level; | |
1047 | int new_level = bidi_resolve_explicit (bidi_it); | |
1048 | int next_char; | |
1049 | bidi_type_t type_of_next; | |
1050 | struct bidi_it saved_it; | |
1051 | ||
1052 | type = bidi_it->type; | |
1053 | override = bidi_it->level_stack[bidi_it->stack_idx].override; | |
1054 | ||
1055 | if (type == UNKNOWN_BT | |
1056 | || type == LRE | |
1057 | || type == LRO | |
1058 | || type == RLE | |
1059 | || type == RLO | |
1060 | || type == PDF) | |
1061 | abort (); | |
1062 | ||
1063 | if (new_level != prev_level | |
1064 | || bidi_it->type == NEUTRAL_B) | |
1065 | { | |
1066 | /* We've got a new embedding level run, compute the directional | |
1067 | type of sor and initialize per-run variables (UAX#9, clause | |
1068 | X10). */ | |
1069 | bidi_set_sor_type (bidi_it, prev_level, new_level); | |
1070 | } | |
1071 | else if (type == NEUTRAL_S || type == NEUTRAL_WS | |
1072 | || type == WEAK_BN || type == STRONG_AL) | |
89d3374a EZ |
1073 | bidi_it->type_after_w1 = type; /* needed in L1 */ |
1074 | bidi_check_type (bidi_it->type_after_w1); | |
b7b65b15 EZ |
1075 | |
1076 | /* Level and directional override status are already recorded in | |
1077 | bidi_it, and do not need any change; see X6. */ | |
1078 | if (override == R2L) /* X6 */ | |
1079 | type = STRONG_R; | |
1080 | else if (override == L2R) | |
1081 | type = STRONG_L; | |
bc5a45f3 | 1082 | else |
b7b65b15 | 1083 | { |
bc5a45f3 | 1084 | if (type == WEAK_NSM) /* W1 */ |
b7b65b15 | 1085 | { |
bc5a45f3 | 1086 | /* Note that we don't need to consider the case where the |
5930fe97 EZ |
1087 | prev character has its type overridden by an RLO or LRO, |
1088 | because then either the type of this NSM would have been | |
1089 | also overridden, or the previous character is outside the | |
1090 | current level run, and thus not relevant to this NSM. | |
1091 | This is why NSM gets the type_after_w1 of the previous | |
1092 | character. */ | |
ebb5722e EZ |
1093 | if (bidi_it->prev.type_after_w1 != UNKNOWN_BT |
1094 | /* if type_after_w1 is NEUTRAL_B, this NSM is at sor */ | |
1095 | && bidi_it->prev.type_after_w1 != NEUTRAL_B) | |
5930fe97 | 1096 | type = bidi_it->prev.type_after_w1; |
bc5a45f3 EZ |
1097 | else if (bidi_it->sor == R2L) |
1098 | type = STRONG_R; | |
1099 | else if (bidi_it->sor == L2R) | |
1100 | type = STRONG_L; | |
1101 | else /* shouldn't happen! */ | |
1102 | abort (); | |
b7b65b15 | 1103 | } |
bc5a45f3 EZ |
1104 | if (type == WEAK_EN /* W2 */ |
1105 | && bidi_it->last_strong.type_after_w1 == STRONG_AL) | |
1106 | type = WEAK_AN; | |
1107 | else if (type == STRONG_AL) /* W3 */ | |
1108 | type = STRONG_R; | |
1109 | else if ((type == WEAK_ES /* W4 */ | |
1110 | && bidi_it->prev.type_after_w1 == WEAK_EN | |
1111 | && bidi_it->prev.orig_type == WEAK_EN) | |
1112 | || (type == WEAK_CS | |
1113 | && ((bidi_it->prev.type_after_w1 == WEAK_EN | |
1114 | && bidi_it->prev.orig_type == WEAK_EN) | |
1115 | || bidi_it->prev.type_after_w1 == WEAK_AN))) | |
b7b65b15 | 1116 | { |
e7402cb2 EZ |
1117 | next_char = |
1118 | bidi_it->bytepos + bidi_it->ch_len >= ZV_BYTE | |
1119 | ? BIDI_EOB : FETCH_CHAR (bidi_it->bytepos + bidi_it->ch_len); | |
6bff6497 | 1120 | type_of_next = bidi_get_type (next_char, override); |
b7b65b15 | 1121 | |
bc5a45f3 | 1122 | if (type_of_next == WEAK_BN |
b7b65b15 EZ |
1123 | || bidi_explicit_dir_char (next_char)) |
1124 | { | |
1125 | bidi_copy_it (&saved_it, bidi_it); | |
1126 | while (bidi_resolve_explicit (bidi_it) == new_level | |
bc5a45f3 | 1127 | && bidi_it->type == WEAK_BN) |
b7b65b15 EZ |
1128 | ; |
1129 | type_of_next = bidi_it->type; | |
b7b65b15 EZ |
1130 | bidi_copy_it (bidi_it, &saved_it); |
1131 | } | |
bc5a45f3 EZ |
1132 | |
1133 | /* If the next character is EN, but the last strong-type | |
1134 | character is AL, that next EN will be changed to AN when | |
1135 | we process it in W2 above. So in that case, this ES | |
1136 | should not be changed into EN. */ | |
1137 | if (type == WEAK_ES | |
1138 | && type_of_next == WEAK_EN | |
1139 | && bidi_it->last_strong.type_after_w1 != STRONG_AL) | |
1140 | type = WEAK_EN; | |
1141 | else if (type == WEAK_CS) | |
b7b65b15 | 1142 | { |
bc5a45f3 EZ |
1143 | if (bidi_it->prev.type_after_w1 == WEAK_AN |
1144 | && (type_of_next == WEAK_AN | |
1145 | /* If the next character is EN, but the last | |
1146 | strong-type character is AL, EN will be later | |
1147 | changed to AN when we process it in W2 above. | |
1148 | So in that case, this ES should not be | |
1149 | changed into EN. */ | |
1150 | || (type_of_next == WEAK_EN | |
1151 | && bidi_it->last_strong.type_after_w1 == STRONG_AL))) | |
1152 | type = WEAK_AN; | |
1153 | else if (bidi_it->prev.type_after_w1 == WEAK_EN | |
1154 | && type_of_next == WEAK_EN | |
1155 | && bidi_it->last_strong.type_after_w1 != STRONG_AL) | |
1156 | type = WEAK_EN; | |
1157 | } | |
1158 | } | |
1159 | else if (type == WEAK_ET /* W5: ET with EN before or after it */ | |
1160 | || type == WEAK_BN) /* W5/Retaining */ | |
1161 | { | |
1162 | if (bidi_it->prev.type_after_w1 == WEAK_EN /* ET/BN w/EN before it */ | |
1163 | || bidi_it->next_en_pos > bidi_it->charpos) | |
1164 | type = WEAK_EN; | |
1165 | else /* W5: ET/BN with EN after it. */ | |
1166 | { | |
1167 | EMACS_INT en_pos = bidi_it->charpos + 1; | |
1168 | ||
1169 | next_char = | |
1170 | bidi_it->bytepos + bidi_it->ch_len >= ZV_BYTE | |
1171 | ? BIDI_EOB : FETCH_CHAR (bidi_it->bytepos + bidi_it->ch_len); | |
1172 | type_of_next = bidi_get_type (next_char, override); | |
1173 | ||
1174 | if (type_of_next == WEAK_ET | |
1175 | || type_of_next == WEAK_BN | |
1176 | || bidi_explicit_dir_char (next_char)) | |
1177 | { | |
1178 | bidi_copy_it (&saved_it, bidi_it); | |
1179 | while (bidi_resolve_explicit (bidi_it) == new_level | |
1180 | && (bidi_it->type == WEAK_BN | |
1181 | || bidi_it->type == WEAK_ET)) | |
1182 | ; | |
1183 | type_of_next = bidi_it->type; | |
1184 | en_pos = bidi_it->charpos; | |
1185 | bidi_copy_it (bidi_it, &saved_it); | |
1186 | } | |
1187 | if (type_of_next == WEAK_EN) | |
b7b65b15 | 1188 | { |
bc5a45f3 EZ |
1189 | /* If the last strong character is AL, the EN we've |
1190 | found will become AN when we get to it (W2). */ | |
1191 | if (bidi_it->last_strong.type_after_w1 != STRONG_AL) | |
1192 | { | |
1193 | type = WEAK_EN; | |
1194 | /* Remember this EN position, to speed up processing | |
1195 | of the next ETs. */ | |
1196 | bidi_it->next_en_pos = en_pos; | |
1197 | } | |
1198 | else if (type == WEAK_BN) | |
1199 | type = NEUTRAL_ON; /* W6/Retaining */ | |
b7b65b15 | 1200 | } |
b7b65b15 EZ |
1201 | } |
1202 | } | |
1203 | } | |
1204 | ||
1205 | if (type == WEAK_ES || type == WEAK_ET || type == WEAK_CS /* W6 */ | |
89d3374a EZ |
1206 | || (type == WEAK_BN |
1207 | && (bidi_it->prev.type_after_w1 == WEAK_CS /* W6/Retaining */ | |
1208 | || bidi_it->prev.type_after_w1 == WEAK_ES | |
1209 | || bidi_it->prev.type_after_w1 == WEAK_ET))) | |
b7b65b15 EZ |
1210 | type = NEUTRAL_ON; |
1211 | ||
1212 | /* Store the type we've got so far, before we clobber it with strong | |
1213 | types in W7 and while resolving neutral types. But leave alone | |
1214 | the original types that were recorded above, because we will need | |
1215 | them for the L1 clause. */ | |
89d3374a EZ |
1216 | if (bidi_it->type_after_w1 == UNKNOWN_BT) |
1217 | bidi_it->type_after_w1 = type; | |
1218 | bidi_check_type (bidi_it->type_after_w1); | |
b7b65b15 EZ |
1219 | |
1220 | if (type == WEAK_EN) /* W7 */ | |
1221 | { | |
89d3374a | 1222 | if ((bidi_it->last_strong.type_after_w1 == STRONG_L) |
b7b65b15 EZ |
1223 | || (bidi_it->last_strong.type == UNKNOWN_BT && bidi_it->sor == L2R)) |
1224 | type = STRONG_L; | |
1225 | } | |
1226 | ||
1227 | bidi_it->type = type; | |
2d6e4628 | 1228 | bidi_check_type (bidi_it->type); |
b7b65b15 EZ |
1229 | return type; |
1230 | } | |
1231 | ||
fd3998ff | 1232 | static bidi_type_t |
b7b65b15 EZ |
1233 | bidi_resolve_neutral (struct bidi_it *bidi_it) |
1234 | { | |
1235 | int prev_level = bidi_it->level_stack[bidi_it->stack_idx].level; | |
1236 | bidi_type_t type = bidi_resolve_weak (bidi_it); | |
1237 | int current_level = bidi_it->level_stack[bidi_it->stack_idx].level; | |
1238 | ||
1239 | if (!(type == STRONG_R | |
1240 | || type == STRONG_L | |
1241 | || type == WEAK_BN | |
1242 | || type == WEAK_EN | |
1243 | || type == WEAK_AN | |
1244 | || type == NEUTRAL_B | |
1245 | || type == NEUTRAL_S | |
1246 | || type == NEUTRAL_WS | |
1247 | || type == NEUTRAL_ON)) | |
1248 | abort (); | |
1249 | ||
1250 | if (bidi_get_category (type) == NEUTRAL | |
1251 | || (type == WEAK_BN && prev_level == current_level)) | |
1252 | { | |
1253 | if (bidi_it->next_for_neutral.type != UNKNOWN_BT) | |
1254 | type = bidi_resolve_neutral_1 (bidi_it->prev_for_neutral.type, | |
1255 | bidi_it->next_for_neutral.type, | |
1256 | current_level); | |
1257 | else | |
1258 | { | |
1259 | /* Arrrgh!! The UAX#9 algorithm is too deeply entrenched in | |
1260 | the assumption of batch-style processing; see clauses W4, | |
1261 | W5, and especially N1, which require to look far forward | |
1262 | (as well as back) in the buffer. May the fleas of a | |
1263 | thousand camels infest the armpits of those who design | |
1264 | supposedly general-purpose algorithms by looking at their | |
1265 | own implementations, and fail to consider other possible | |
1266 | implementations! */ | |
1267 | struct bidi_it saved_it; | |
1268 | bidi_type_t next_type; | |
1269 | ||
1270 | if (bidi_it->scan_dir == -1) | |
1271 | abort (); | |
1272 | ||
1273 | bidi_copy_it (&saved_it, bidi_it); | |
1274 | /* Scan the text forward until we find the first non-neutral | |
1275 | character, and then use that to resolve the neutral we | |
1276 | are dealing with now. We also cache the scanned iterator | |
1277 | states, to salvage some of the effort later. */ | |
1278 | bidi_cache_iterator_state (bidi_it, 0); | |
1279 | do { | |
1280 | /* Record the info about the previous character, so that | |
1281 | it will be cached below with this state. */ | |
89d3374a | 1282 | if (bidi_it->type_after_w1 != WEAK_BN /* W1/Retaining */ |
b7b65b15 EZ |
1283 | && bidi_it->type != WEAK_BN) |
1284 | bidi_remember_char (&bidi_it->prev, bidi_it); | |
1285 | type = bidi_resolve_weak (bidi_it); | |
1286 | /* Paragraph separators have their levels fully resolved | |
1287 | at this point, so cache them as resolved. */ | |
1288 | bidi_cache_iterator_state (bidi_it, type == NEUTRAL_B); | |
1289 | /* FIXME: implement L1 here, by testing for a newline and | |
1290 | resetting the level for any sequence of whitespace | |
1291 | characters adjacent to it. */ | |
1292 | } while (!(type == NEUTRAL_B | |
1293 | || (type != WEAK_BN | |
1294 | && bidi_get_category (type) != NEUTRAL) | |
1295 | /* This is all per level run, so stop when we | |
1296 | reach the end of this level run. */ | |
1297 | || bidi_it->level_stack[bidi_it->stack_idx].level != | |
1298 | current_level)); | |
1299 | ||
1300 | bidi_remember_char (&saved_it.next_for_neutral, bidi_it); | |
1301 | ||
1302 | switch (type) | |
1303 | { | |
1304 | case STRONG_L: | |
1305 | case STRONG_R: | |
1306 | case STRONG_AL: | |
1307 | next_type = type; | |
1308 | break; | |
1309 | case WEAK_EN: | |
1310 | case WEAK_AN: | |
1311 | /* N1: ``European and Arabic numbers are treated as | |
1312 | though they were R.'' */ | |
1313 | next_type = STRONG_R; | |
1314 | saved_it.next_for_neutral.type = STRONG_R; | |
1315 | break; | |
1316 | case WEAK_BN: | |
1317 | if (!bidi_explicit_dir_char (bidi_it->ch)) | |
1318 | abort (); /* can't happen: BNs are skipped */ | |
1319 | /* FALLTHROUGH */ | |
1320 | case NEUTRAL_B: | |
1321 | /* Marched all the way to the end of this level run. | |
1322 | We need to use the eor type, whose information is | |
1323 | stored by bidi_set_sor_type in the prev_for_neutral | |
1324 | member. */ | |
1325 | if (saved_it.type != WEAK_BN | |
89d3374a | 1326 | || bidi_get_category (bidi_it->prev.type_after_w1) == NEUTRAL) |
b7b65b15 EZ |
1327 | { |
1328 | next_type = bidi_it->prev_for_neutral.type; | |
1329 | saved_it.next_for_neutral.type = next_type; | |
2d6e4628 | 1330 | bidi_check_type (next_type); |
b7b65b15 EZ |
1331 | } |
1332 | else | |
1333 | { | |
1334 | /* This is a BN which does not adjoin neutrals. | |
1335 | Leave its type alone. */ | |
1336 | bidi_copy_it (bidi_it, &saved_it); | |
1337 | return bidi_it->type; | |
1338 | } | |
1339 | break; | |
1340 | default: | |
1341 | abort (); | |
1342 | } | |
1343 | type = bidi_resolve_neutral_1 (saved_it.prev_for_neutral.type, | |
1344 | next_type, current_level); | |
1345 | saved_it.type = type; | |
2d6e4628 | 1346 | bidi_check_type (type); |
b7b65b15 EZ |
1347 | bidi_copy_it (bidi_it, &saved_it); |
1348 | } | |
1349 | } | |
1350 | return type; | |
1351 | } | |
1352 | ||
1353 | /* Given an iterator state in BIDI_IT, advance one character position | |
1354 | in the buffer to the next character (in the logical order), resolve | |
1355 | the bidi type of that next character, and return that type. */ | |
fd3998ff | 1356 | static bidi_type_t |
b7b65b15 EZ |
1357 | bidi_type_of_next_char (struct bidi_it *bidi_it) |
1358 | { | |
1359 | bidi_type_t type; | |
1360 | ||
1361 | /* This should always be called during a forward scan. */ | |
1362 | if (bidi_it->scan_dir != 1) | |
1363 | abort (); | |
1364 | ||
1365 | /* Reset the limit until which to ignore BNs if we step out of the | |
1366 | area where we found only empty levels. */ | |
1367 | if ((bidi_it->ignore_bn_limit > 0 | |
1368 | && bidi_it->ignore_bn_limit <= bidi_it->charpos) | |
1369 | || (bidi_it->ignore_bn_limit == -1 | |
1370 | && !bidi_explicit_dir_char (bidi_it->ch))) | |
1371 | bidi_it->ignore_bn_limit = 0; | |
1372 | ||
1373 | type = bidi_resolve_neutral (bidi_it); | |
1374 | ||
1375 | return type; | |
1376 | } | |
1377 | ||
1378 | /* Given an iterator state BIDI_IT, advance one character position in | |
1379 | the buffer to the next character (in the logical order), resolve | |
1380 | the embedding and implicit levels of that next character, and | |
1381 | return the resulting level. */ | |
fd3998ff | 1382 | static int |
b7b65b15 EZ |
1383 | bidi_level_of_next_char (struct bidi_it *bidi_it) |
1384 | { | |
1385 | bidi_type_t type; | |
1386 | int level, prev_level = -1; | |
1387 | struct bidi_saved_info next_for_neutral; | |
1388 | ||
1389 | if (bidi_it->scan_dir == 1) | |
1390 | { | |
1391 | /* There's no sense in trying to advance if we hit end of text. */ | |
1502b819 | 1392 | if (bidi_it->bytepos >= ZV_BYTE) |
b7b65b15 EZ |
1393 | return bidi_it->resolved_level; |
1394 | ||
1395 | /* Record the info about the previous character. */ | |
89d3374a | 1396 | if (bidi_it->type_after_w1 != WEAK_BN /* W1/Retaining */ |
b7b65b15 EZ |
1397 | && bidi_it->type != WEAK_BN) |
1398 | bidi_remember_char (&bidi_it->prev, bidi_it); | |
89d3374a EZ |
1399 | if (bidi_it->type_after_w1 == STRONG_R |
1400 | || bidi_it->type_after_w1 == STRONG_L | |
1401 | || bidi_it->type_after_w1 == STRONG_AL) | |
b7b65b15 EZ |
1402 | bidi_remember_char (&bidi_it->last_strong, bidi_it); |
1403 | /* FIXME: it sounds like we don't need both prev and | |
1404 | prev_for_neutral members, but I'm leaving them both for now. */ | |
1405 | if (bidi_it->type == STRONG_R || bidi_it->type == STRONG_L | |
1406 | || bidi_it->type == WEAK_EN || bidi_it->type == WEAK_AN) | |
1407 | bidi_remember_char (&bidi_it->prev_for_neutral, bidi_it); | |
1408 | ||
1409 | /* If we overstepped the characters used for resolving neutrals | |
1410 | and whitespace, invalidate their info in the iterator. */ | |
1411 | if (bidi_it->charpos >= bidi_it->next_for_neutral.charpos) | |
1412 | bidi_it->next_for_neutral.type = UNKNOWN_BT; | |
1413 | if (bidi_it->next_en_pos >= 0 | |
1414 | && bidi_it->charpos >= bidi_it->next_en_pos) | |
1415 | bidi_it->next_en_pos = -1; | |
1416 | if (bidi_it->next_for_ws.type != UNKNOWN_BT | |
1417 | && bidi_it->charpos >= bidi_it->next_for_ws.charpos) | |
1418 | bidi_it->next_for_ws.type = UNKNOWN_BT; | |
1419 | ||
1420 | /* This must be taken before we fill the iterator with the info | |
1421 | about the next char. If we scan backwards, the iterator | |
1422 | state must be already cached, so there's no need to know the | |
1423 | embedding level of the previous character, since we will be | |
1424 | returning to our caller shortly. */ | |
1425 | prev_level = bidi_it->level_stack[bidi_it->stack_idx].level; | |
1426 | } | |
1427 | next_for_neutral = bidi_it->next_for_neutral; | |
1428 | ||
1429 | /* Perhaps it is already cached. */ | |
1430 | type = bidi_cache_find (bidi_it->charpos + bidi_it->scan_dir, -1, bidi_it); | |
1431 | if (type != UNKNOWN_BT) | |
1432 | { | |
1433 | /* Don't lose the information for resolving neutrals! The | |
1434 | cached states could have been cached before their | |
1435 | next_for_neutral member was computed. If we are on our way | |
1436 | forward, we can simply take the info from the previous | |
1437 | state. */ | |
1438 | if (bidi_it->scan_dir == 1 | |
1439 | && bidi_it->next_for_neutral.type == UNKNOWN_BT) | |
1440 | bidi_it->next_for_neutral = next_for_neutral; | |
1441 | ||
1442 | /* If resolved_level is -1, it means this state was cached | |
1443 | before it was completely resolved, so we cannot return | |
1444 | it. */ | |
1445 | if (bidi_it->resolved_level != -1) | |
1446 | return bidi_it->resolved_level; | |
1447 | } | |
1448 | if (bidi_it->scan_dir == -1) | |
1449 | /* If we are going backwards, the iterator state is already cached | |
1450 | from previous scans, and should be fully resolved. */ | |
1451 | abort (); | |
1452 | ||
1453 | if (type == UNKNOWN_BT) | |
1454 | type = bidi_type_of_next_char (bidi_it); | |
1455 | ||
1456 | if (type == NEUTRAL_B) | |
1457 | return bidi_it->resolved_level; | |
1458 | ||
1459 | level = bidi_it->level_stack[bidi_it->stack_idx].level; | |
1460 | if ((bidi_get_category (type) == NEUTRAL /* && type != NEUTRAL_B */) | |
1461 | || (type == WEAK_BN && prev_level == level)) | |
1462 | { | |
1463 | if (bidi_it->next_for_neutral.type == UNKNOWN_BT) | |
1464 | abort (); | |
1465 | ||
1466 | /* If the cached state shows a neutral character, it was not | |
1467 | resolved by bidi_resolve_neutral, so do it now. */ | |
1468 | type = bidi_resolve_neutral_1 (bidi_it->prev_for_neutral.type, | |
1469 | bidi_it->next_for_neutral.type, | |
1470 | level); | |
1471 | } | |
1472 | ||
1473 | if (!(type == STRONG_R | |
1474 | || type == STRONG_L | |
1475 | || type == WEAK_BN | |
1476 | || type == WEAK_EN | |
1477 | || type == WEAK_AN)) | |
1478 | abort (); | |
1479 | bidi_it->type = type; | |
2d6e4628 | 1480 | bidi_check_type (bidi_it->type); |
b7b65b15 EZ |
1481 | |
1482 | /* For L1 below, we need to know, for each WS character, whether | |
1483 | it belongs to a sequence of WS characters preceeding a newline | |
1484 | or a TAB or a paragraph separator. */ | |
89d3374a | 1485 | if (bidi_it->orig_type == NEUTRAL_WS |
b7b65b15 EZ |
1486 | && bidi_it->next_for_ws.type == UNKNOWN_BT) |
1487 | { | |
1488 | int ch; | |
1489 | int clen = bidi_it->ch_len; | |
6bff6497 EZ |
1490 | EMACS_INT bpos = bidi_it->bytepos; |
1491 | EMACS_INT cpos = bidi_it->charpos; | |
b7b65b15 EZ |
1492 | bidi_type_t chtype; |
1493 | ||
1494 | do { | |
1495 | /*_fetch_multibyte_char_len = 1;*/ | |
e7402cb2 | 1496 | ch = bpos + clen >= ZV_BYTE ? BIDI_EOB : FETCH_CHAR (bpos + clen); |
b7b65b15 EZ |
1497 | bpos += clen; |
1498 | cpos++; | |
e7402cb2 EZ |
1499 | clen = (ch == BIDI_EOB ? 1 : CHAR_BYTES (ch)); |
1500 | if (ch == '\n' || ch == BIDI_EOB /* || ch == LINESEP_CHAR */) | |
b7b65b15 EZ |
1501 | chtype = NEUTRAL_B; |
1502 | else | |
6bff6497 | 1503 | chtype = bidi_get_type (ch, NEUTRAL_DIR); |
b7b65b15 EZ |
1504 | } while (chtype == NEUTRAL_WS || chtype == WEAK_BN |
1505 | || bidi_explicit_dir_char (ch)); /* L1/Retaining */ | |
1506 | bidi_it->next_for_ws.type = chtype; | |
2d6e4628 | 1507 | bidi_check_type (bidi_it->next_for_ws.type); |
b7b65b15 EZ |
1508 | bidi_it->next_for_ws.charpos = cpos; |
1509 | bidi_it->next_for_ws.bytepos = bpos; | |
1510 | } | |
1511 | ||
1512 | /* Resolve implicit levels, with a twist: PDFs get the embedding | |
1513 | level of the enbedding they terminate. See below for the | |
1514 | reason. */ | |
89d3374a | 1515 | if (bidi_it->orig_type == PDF |
b7b65b15 EZ |
1516 | /* Don't do this if this formatting code didn't change the |
1517 | embedding level due to invalid or empty embeddings. */ | |
1518 | && prev_level != level) | |
1519 | { | |
1520 | /* Don't look in UAX#9 for the reason for this: it's our own | |
1521 | private quirk. The reason is that we want the formatting | |
1522 | codes to be delivered so that they bracket the text of their | |
1523 | embedding. For example, given the text | |
1524 | ||
1525 | {RLO}teST{PDF} | |
1526 | ||
1527 | we want it to be displayed as | |
1528 | ||
1529 | {RLO}STet{PDF} | |
1530 | ||
1531 | not as | |
1532 | ||
1533 | STet{RLO}{PDF} | |
1534 | ||
1535 | which will result because we bump up the embedding level as | |
1536 | soon as we see the RLO and pop it as soon as we see the PDF, | |
1537 | so RLO itself has the same embedding level as "teST", and | |
1538 | thus would be normally delivered last, just before the PDF. | |
1539 | The switch below fiddles with the level of PDF so that this | |
1540 | ugly side effect does not happen. | |
1541 | ||
1542 | (This is, of course, only important if the formatting codes | |
e7402cb2 EZ |
1543 | are actually displayed, but Emacs does need to display them |
1544 | if the user wants to.) */ | |
b7b65b15 EZ |
1545 | level = prev_level; |
1546 | } | |
89d3374a EZ |
1547 | else if (bidi_it->orig_type == NEUTRAL_B /* L1 */ |
1548 | || bidi_it->orig_type == NEUTRAL_S | |
e7402cb2 EZ |
1549 | || bidi_it->ch == '\n' || bidi_it->ch == BIDI_EOB |
1550 | /* || bidi_it->ch == LINESEP_CHAR */ | |
89d3374a | 1551 | || (bidi_it->orig_type == NEUTRAL_WS |
b7b65b15 EZ |
1552 | && (bidi_it->next_for_ws.type == NEUTRAL_B |
1553 | || bidi_it->next_for_ws.type == NEUTRAL_S))) | |
1554 | level = bidi_it->level_stack[0].level; | |
1555 | else if ((level & 1) == 0) /* I1 */ | |
1556 | { | |
1557 | if (type == STRONG_R) | |
1558 | level++; | |
1559 | else if (type == WEAK_EN || type == WEAK_AN) | |
1560 | level += 2; | |
1561 | } | |
1562 | else /* I2 */ | |
1563 | { | |
1564 | if (type == STRONG_L || type == WEAK_EN || type == WEAK_AN) | |
1565 | level++; | |
1566 | } | |
1567 | ||
1568 | bidi_it->resolved_level = level; | |
1569 | return level; | |
1570 | } | |
1571 | ||
1572 | /* Move to the other edge of a level given by LEVEL. If END_FLAG is | |
1573 | non-zero, we are at the end of a level, and we need to prepare to | |
1574 | resume the scan of the lower level. | |
1575 | ||
1576 | If this level's other edge is cached, we simply jump to it, filling | |
1577 | the iterator structure with the iterator state on the other edge. | |
1578 | Otherwise, we walk the buffer until we come back to the same level | |
1579 | as LEVEL. | |
1580 | ||
1581 | Note: we are not talking here about a ``level run'' in the UAX#9 | |
1582 | sense of the term, but rather about a ``level'' which includes | |
1583 | all the levels higher than it. In other words, given the levels | |
1584 | like this: | |
1585 | ||
1586 | 11111112222222333333334443343222222111111112223322111 | |
1587 | A B C | |
1588 | ||
1589 | and assuming we are at point A scanning left to right, this | |
1590 | function moves to point C, whereas the UAX#9 ``level 2 run'' ends | |
1591 | at point B. */ | |
1592 | static void | |
1593 | bidi_find_other_level_edge (struct bidi_it *bidi_it, int level, int end_flag) | |
1594 | { | |
1595 | int dir = end_flag ? -bidi_it->scan_dir : bidi_it->scan_dir; | |
1596 | int idx; | |
1597 | ||
1598 | /* Try the cache first. */ | |
1599 | if ((idx = bidi_cache_find_level_change (level, dir, end_flag)) >= 0) | |
1600 | bidi_cache_fetch_state (idx, bidi_it); | |
1601 | else | |
1602 | { | |
1603 | int new_level; | |
1604 | ||
1605 | if (end_flag) | |
1606 | abort (); /* if we are at end of level, its edges must be cached */ | |
1607 | ||
1608 | bidi_cache_iterator_state (bidi_it, 1); | |
1609 | do { | |
1610 | new_level = bidi_level_of_next_char (bidi_it); | |
1611 | bidi_cache_iterator_state (bidi_it, 1); | |
1612 | } while (new_level >= level); | |
1613 | } | |
1614 | } | |
1615 | ||
1616 | void | |
4b292a22 | 1617 | bidi_move_to_visually_next (struct bidi_it *bidi_it) |
b7b65b15 EZ |
1618 | { |
1619 | int old_level, new_level, next_level; | |
9c82e145 | 1620 | struct bidi_it sentinel; |
b7b65b15 EZ |
1621 | |
1622 | if (bidi_it->scan_dir == 0) | |
1623 | { | |
1624 | bidi_it->scan_dir = 1; /* default to logical order */ | |
1625 | } | |
1626 | ||
be39f003 EZ |
1627 | /* If we just passed a newline, initialize for the next line. */ |
1628 | if (!bidi_it->first_elt && bidi_it->orig_type == NEUTRAL_B) | |
1629 | bidi_line_init (bidi_it); | |
1630 | ||
6dcfd253 EZ |
1631 | /* Prepare the sentinel iterator state, and cache it. When we bump |
1632 | into it, scanning backwards, we'll know that the last non-base | |
1633 | level is exhausted. */ | |
b7b65b15 | 1634 | if (bidi_cache_idx == 0) |
9c82e145 EZ |
1635 | { |
1636 | bidi_copy_it (&sentinel, bidi_it); | |
1637 | if (bidi_it->first_elt) | |
1638 | { | |
1639 | sentinel.charpos--; /* cached charpos needs to be monotonic */ | |
1640 | sentinel.bytepos--; | |
1641 | sentinel.ch = '\n'; /* doesn't matter, but why not? */ | |
1642 | sentinel.ch_len = 1; | |
1643 | } | |
6dcfd253 | 1644 | bidi_cache_iterator_state (&sentinel, 1); |
9c82e145 | 1645 | } |
b7b65b15 EZ |
1646 | |
1647 | old_level = bidi_it->resolved_level; | |
1648 | new_level = bidi_level_of_next_char (bidi_it); | |
b7b65b15 EZ |
1649 | |
1650 | /* Reordering of resolved levels (clause L2) is implemented by | |
1651 | jumping to the other edge of the level and flipping direction of | |
c0546589 | 1652 | scanning the text whenever we find a level change. */ |
b7b65b15 EZ |
1653 | if (new_level != old_level) |
1654 | { | |
1655 | int ascending = new_level > old_level; | |
1656 | int level_to_search = ascending ? old_level + 1 : old_level; | |
1657 | int incr = ascending ? 1 : -1; | |
1658 | int expected_next_level = old_level + incr; | |
1659 | ||
b7b65b15 EZ |
1660 | /* Jump (or walk) to the other edge of this level. */ |
1661 | bidi_find_other_level_edge (bidi_it, level_to_search, !ascending); | |
1662 | /* Switch scan direction and peek at the next character in the | |
1663 | new direction. */ | |
1664 | bidi_it->scan_dir = -bidi_it->scan_dir; | |
1665 | ||
1666 | /* The following loop handles the case where the resolved level | |
1667 | jumps by more than one. This is typical for numbers inside a | |
1668 | run of text with left-to-right embedding direction, but can | |
1669 | also happen in other situations. In those cases the decision | |
1670 | where to continue after a level change, and in what direction, | |
1671 | is tricky. For example, given a text like below: | |
1672 | ||
1673 | abcdefgh | |
1674 | 11336622 | |
1675 | ||
1676 | (where the numbers below the text show the resolved levels), | |
1677 | the result of reordering according to UAX#9 should be this: | |
1678 | ||
1679 | efdcghba | |
1680 | ||
1681 | This is implemented by the loop below which flips direction | |
1682 | and jumps to the other edge of the level each time it finds | |
1683 | the new level not to be the expected one. The expected level | |
1684 | is always one more or one less than the previous one. */ | |
1685 | next_level = bidi_peek_at_next_level (bidi_it); | |
1686 | while (next_level != expected_next_level) | |
1687 | { | |
1688 | expected_next_level += incr; | |
1689 | level_to_search += incr; | |
1690 | bidi_find_other_level_edge (bidi_it, level_to_search, !ascending); | |
1691 | bidi_it->scan_dir = -bidi_it->scan_dir; | |
1692 | next_level = bidi_peek_at_next_level (bidi_it); | |
1693 | } | |
1694 | ||
1695 | /* Finally, deliver the next character in the new direction. */ | |
1696 | next_level = bidi_level_of_next_char (bidi_it); | |
1697 | } | |
1698 | ||
b44d9321 EZ |
1699 | /* Take note when we have just processed the newline that precedes |
1700 | the end of the paragraph. The next time we are about to be | |
1701 | called, set_iterator_to_next will automatically reinit the | |
1702 | paragraph direction, if needed. We do this at the newline before | |
1703 | the paragraph separator, because the next character might not be | |
1704 | the first character of the next paragraph, due to the bidi | |
c0546589 EZ |
1705 | reordering, whereas we _must_ know the paragraph base direction |
1706 | _before_ we process the paragraph's text, since the base | |
1707 | direction affects the reordering. */ | |
6bff6497 | 1708 | if (bidi_it->scan_dir == 1 |
be39f003 EZ |
1709 | && bidi_it->orig_type == NEUTRAL_B |
1710 | && bidi_it->bytepos < ZV_BYTE) | |
1711 | { | |
1712 | EMACS_INT sep_len = | |
1713 | bidi_at_paragraph_end (bidi_it->charpos + 1, | |
1714 | bidi_it->bytepos + bidi_it->ch_len); | |
1715 | if (sep_len >= 0) | |
1716 | { | |
1717 | bidi_it->new_paragraph = 1; | |
b44d9321 EZ |
1718 | /* Record the buffer position of the last character of the |
1719 | paragraph separator. */ | |
1720 | bidi_it->separator_limit = bidi_it->charpos + 1 + sep_len; | |
be39f003 EZ |
1721 | } |
1722 | } | |
6bff6497 | 1723 | |
b7b65b15 EZ |
1724 | if (bidi_it->scan_dir == 1 && bidi_cache_idx) |
1725 | { | |
1726 | /* If we are at paragraph's base embedding level and beyond the | |
1727 | last cached position, the cache's job is done and we can | |
1728 | discard it. */ | |
1729 | if (bidi_it->resolved_level == bidi_it->level_stack[0].level | |
1730 | && bidi_it->charpos > bidi_cache[bidi_cache_idx - 1].charpos) | |
1731 | bidi_cache_reset (); | |
1732 | /* But as long as we are caching during forward scan, we must | |
1733 | cache each state, or else the cache integrity will be | |
1734 | compromised: it assumes cached states correspond to buffer | |
1735 | positions 1:1. */ | |
1736 | else | |
1737 | bidi_cache_iterator_state (bidi_it, 1); | |
1738 | } | |
1739 | } | |
1740 | ||
1741 | /* This is meant to be called from within the debugger, whenever you | |
1742 | wish to examine the cache contents. */ | |
1743 | void | |
1744 | bidi_dump_cached_states (void) | |
1745 | { | |
1746 | int i; | |
1747 | int ndigits = 1; | |
1748 | ||
1749 | if (bidi_cache_idx == 0) | |
1750 | { | |
1751 | fprintf (stderr, "The cache is empty.\n"); | |
1752 | return; | |
1753 | } | |
1754 | fprintf (stderr, "Total of %d state%s in cache:\n", | |
1755 | bidi_cache_idx, bidi_cache_idx == 1 ? "" : "s"); | |
1756 | ||
1757 | for (i = bidi_cache[bidi_cache_idx - 1].charpos; i > 0; i /= 10) | |
1758 | ndigits++; | |
1759 | fputs ("ch ", stderr); | |
1760 | for (i = 0; i < bidi_cache_idx; i++) | |
1761 | fprintf (stderr, "%*c", ndigits, bidi_cache[i].ch); | |
1762 | fputs ("\n", stderr); | |
1763 | fputs ("lvl ", stderr); | |
1764 | for (i = 0; i < bidi_cache_idx; i++) | |
1765 | fprintf (stderr, "%*d", ndigits, bidi_cache[i].resolved_level); | |
1766 | fputs ("\n", stderr); | |
1767 | fputs ("pos ", stderr); | |
1768 | for (i = 0; i < bidi_cache_idx; i++) | |
1769 | fprintf (stderr, "%*d", ndigits, bidi_cache[i].charpos); | |
1770 | fputs ("\n", stderr); | |
1771 | } |