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 | ||
cbc4fd20 | 71 | static Lisp_Object bidi_type_table, bidi_mirror_table; |
b7b65b15 | 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 | 108 | static void |
971de7fb | 109 | bidi_initialize (void) |
b7b65b15 | 110 | { |
317fbf33 EZ |
111 | |
112 | #include "biditype.h" | |
cbc4fd20 | 113 | #include "bidimirror.h" |
317fbf33 | 114 | |
b7b65b15 EZ |
115 | int i; |
116 | ||
117 | bidi_type_table = Fmake_char_table (Qnil, make_number (STRONG_L)); | |
2d6e4628 | 118 | staticpro (&bidi_type_table); |
b7b65b15 EZ |
119 | |
120 | for (i = 0; i < sizeof bidi_type / sizeof bidi_type[0]; i++) | |
317fbf33 | 121 | char_table_set_range (bidi_type_table, bidi_type[i].from, bidi_type[i].to, |
b7b65b15 | 122 | make_number (bidi_type[i].type)); |
6bff6497 | 123 | |
cbc4fd20 EZ |
124 | bidi_mirror_table = Fmake_char_table (Qnil, Qnil); |
125 | staticpro (&bidi_mirror_table); | |
126 | ||
127 | for (i = 0; i < sizeof bidi_mirror / sizeof bidi_mirror[0]; i++) | |
128 | char_table_set (bidi_mirror_table, bidi_mirror[i].from, | |
129 | make_number (bidi_mirror[i].to)); | |
130 | ||
b4bf28b7 SM |
131 | Qparagraph_start = intern ("paragraph-start"); |
132 | staticpro (&Qparagraph_start); | |
372b7a95 EZ |
133 | paragraph_start_re = Fsymbol_value (Qparagraph_start); |
134 | if (!STRINGP (paragraph_start_re)) | |
135 | paragraph_start_re = build_string ("\f\\|[ \t]*$"); | |
136 | staticpro (¶graph_start_re); | |
b4bf28b7 SM |
137 | Qparagraph_separate = intern ("paragraph-separate"); |
138 | staticpro (&Qparagraph_separate); | |
372b7a95 EZ |
139 | paragraph_separate_re = Fsymbol_value (Qparagraph_separate); |
140 | if (!STRINGP (paragraph_separate_re)) | |
141 | paragraph_separate_re = build_string ("[ \t\f]*$"); | |
142 | staticpro (¶graph_separate_re); | |
b7b65b15 EZ |
143 | bidi_initialized = 1; |
144 | } | |
145 | ||
6bff6497 EZ |
146 | /* Return the bidi type of a character CH, subject to the current |
147 | directional OVERRIDE. */ | |
fd3998ff | 148 | static INLINE bidi_type_t |
6bff6497 | 149 | bidi_get_type (int ch, bidi_dir_t override) |
b7b65b15 | 150 | { |
6bff6497 EZ |
151 | bidi_type_t default_type; |
152 | ||
e7402cb2 EZ |
153 | if (ch == BIDI_EOB) |
154 | return NEUTRAL_B; | |
e342a24d EZ |
155 | if (ch < 0 || ch > MAX_CHAR) |
156 | abort (); | |
6bff6497 EZ |
157 | |
158 | default_type = (bidi_type_t) XINT (CHAR_TABLE_REF (bidi_type_table, ch)); | |
159 | ||
160 | if (override == NEUTRAL_DIR) | |
161 | return default_type; | |
162 | ||
163 | switch (default_type) | |
164 | { | |
165 | /* Although UAX#9 does not tell, it doesn't make sense to | |
166 | override NEUTRAL_B and LRM/RLM characters. */ | |
167 | case NEUTRAL_B: | |
168 | case LRE: | |
169 | case LRO: | |
170 | case RLE: | |
171 | case RLO: | |
172 | case PDF: | |
173 | return default_type; | |
174 | default: | |
175 | switch (ch) | |
176 | { | |
177 | case LRM_CHAR: | |
178 | case RLM_CHAR: | |
179 | return default_type; | |
180 | default: | |
181 | if (override == L2R) /* X6 */ | |
182 | return STRONG_L; | |
183 | else if (override == R2L) | |
184 | return STRONG_R; | |
185 | else | |
186 | abort (); /* can't happen: handled above */ | |
187 | } | |
188 | } | |
b7b65b15 EZ |
189 | } |
190 | ||
2d6e4628 EZ |
191 | void |
192 | bidi_check_type (bidi_type_t type) | |
193 | { | |
194 | if (type < UNKNOWN_BT || type > NEUTRAL_ON) | |
195 | abort (); | |
196 | } | |
197 | ||
b7b65b15 | 198 | /* Given a bidi TYPE of a character, return its category. */ |
fd3998ff | 199 | static INLINE bidi_category_t |
b7b65b15 EZ |
200 | bidi_get_category (bidi_type_t type) |
201 | { | |
202 | switch (type) | |
203 | { | |
204 | case UNKNOWN_BT: | |
205 | return UNKNOWN_BC; | |
206 | case STRONG_L: | |
207 | case STRONG_R: | |
208 | case STRONG_AL: | |
209 | case LRE: | |
210 | case LRO: | |
211 | case RLE: | |
212 | case RLO: | |
213 | return STRONG; | |
214 | case PDF: /* ??? really?? */ | |
215 | case WEAK_EN: | |
216 | case WEAK_ES: | |
217 | case WEAK_ET: | |
218 | case WEAK_AN: | |
219 | case WEAK_CS: | |
220 | case WEAK_NSM: | |
221 | case WEAK_BN: | |
222 | return WEAK; | |
223 | case NEUTRAL_B: | |
224 | case NEUTRAL_S: | |
225 | case NEUTRAL_WS: | |
226 | case NEUTRAL_ON: | |
227 | return NEUTRAL; | |
228 | default: | |
229 | abort (); | |
230 | } | |
231 | } | |
232 | ||
a6e8d97c EZ |
233 | /* Return the mirrored character of C, if it has one. If C has no |
234 | mirrored counterpart, return C. | |
235 | Note: The conditions in UAX#9 clause L4 regarding the surrounding | |
236 | context must be tested by the caller. */ | |
b7b65b15 EZ |
237 | int |
238 | bidi_mirror_char (int c) | |
239 | { | |
cbc4fd20 EZ |
240 | Lisp_Object val; |
241 | ||
242 | if (c == BIDI_EOB) | |
243 | return c; | |
244 | if (c < 0 || c > MAX_CHAR) | |
245 | abort (); | |
b7b65b15 | 246 | |
cbc4fd20 EZ |
247 | val = CHAR_TABLE_REF (bidi_mirror_table, c); |
248 | if (INTEGERP (val)) | |
b7b65b15 | 249 | { |
cbc4fd20 | 250 | int v = XINT (val); |
b7b65b15 | 251 | |
cbc4fd20 EZ |
252 | if (v < 0 || v > MAX_CHAR) |
253 | abort (); | |
254 | ||
255 | return v; | |
b7b65b15 | 256 | } |
cbc4fd20 | 257 | |
b7b65b15 EZ |
258 | return c; |
259 | } | |
260 | ||
261 | /* Copy the bidi iterator from FROM to TO. To save cycles, this only | |
262 | copies the part of the level stack that is actually in use. */ | |
fd3998ff | 263 | static INLINE void |
b7b65b15 EZ |
264 | bidi_copy_it (struct bidi_it *to, struct bidi_it *from) |
265 | { | |
266 | int i; | |
267 | ||
e69a9370 EZ |
268 | /* Copy everything except the level stack and beyond. */ |
269 | memcpy (to, from, ((size_t)&((struct bidi_it *)0)->level_stack[0])); | |
b7b65b15 EZ |
270 | |
271 | /* Copy the active part of the level stack. */ | |
272 | to->level_stack[0] = from->level_stack[0]; /* level zero is always in use */ | |
273 | for (i = 1; i <= from->stack_idx; i++) | |
274 | to->level_stack[i] = from->level_stack[i]; | |
275 | } | |
276 | ||
277 | /* Caching the bidi iterator states. */ | |
278 | ||
2fe72643 EZ |
279 | #define BIDI_CACHE_CHUNK 200 |
280 | static struct bidi_it *bidi_cache; | |
281 | static size_t bidi_cache_size = 0; | |
0416466c | 282 | static size_t elsz = sizeof (struct bidi_it); |
2fe72643 EZ |
283 | static int bidi_cache_idx; /* next unused cache slot */ |
284 | static int bidi_cache_last_idx; /* slot of last cache hit */ | |
b7b65b15 | 285 | |
fd3998ff | 286 | static INLINE void |
b7b65b15 EZ |
287 | bidi_cache_reset (void) |
288 | { | |
289 | bidi_cache_idx = 0; | |
290 | bidi_cache_last_idx = -1; | |
291 | } | |
292 | ||
2fe72643 EZ |
293 | static INLINE void |
294 | bidi_cache_shrink (void) | |
295 | { | |
296 | if (bidi_cache_size > BIDI_CACHE_CHUNK) | |
297 | { | |
0416466c EZ |
298 | bidi_cache_size = BIDI_CACHE_CHUNK; |
299 | bidi_cache = | |
300 | (struct bidi_it *) xrealloc (bidi_cache, bidi_cache_size * elsz); | |
2fe72643 EZ |
301 | } |
302 | bidi_cache_reset (); | |
303 | } | |
304 | ||
fd3998ff | 305 | static INLINE void |
b7b65b15 EZ |
306 | bidi_cache_fetch_state (int idx, struct bidi_it *bidi_it) |
307 | { | |
308 | int current_scan_dir = bidi_it->scan_dir; | |
309 | ||
310 | if (idx < 0 || idx >= bidi_cache_idx) | |
311 | abort (); | |
312 | ||
313 | bidi_copy_it (bidi_it, &bidi_cache[idx]); | |
314 | bidi_it->scan_dir = current_scan_dir; | |
315 | bidi_cache_last_idx = idx; | |
316 | } | |
317 | ||
318 | /* Find a cached state with a given CHARPOS and resolved embedding | |
319 | level less or equal to LEVEL. if LEVEL is -1, disregard the | |
320 | resolved levels in cached states. DIR, if non-zero, means search | |
321 | in that direction from the last cache hit. */ | |
fd3998ff | 322 | static INLINE int |
b7b65b15 EZ |
323 | bidi_cache_search (int charpos, int level, int dir) |
324 | { | |
325 | int i, i_start; | |
326 | ||
327 | if (bidi_cache_idx) | |
328 | { | |
329 | if (charpos < bidi_cache[bidi_cache_last_idx].charpos) | |
330 | dir = -1; | |
331 | else if (charpos > bidi_cache[bidi_cache_last_idx].charpos) | |
332 | dir = 1; | |
333 | if (dir) | |
334 | i_start = bidi_cache_last_idx; | |
335 | else | |
336 | { | |
337 | dir = -1; | |
338 | i_start = bidi_cache_idx - 1; | |
339 | } | |
340 | ||
341 | if (dir < 0) | |
342 | { | |
343 | /* Linear search for now; FIXME! */ | |
344 | for (i = i_start; i >= 0; i--) | |
345 | if (bidi_cache[i].charpos == charpos | |
346 | && (level == -1 || bidi_cache[i].resolved_level <= level)) | |
347 | return i; | |
348 | } | |
349 | else | |
350 | { | |
351 | for (i = i_start; i < bidi_cache_idx; i++) | |
352 | if (bidi_cache[i].charpos == charpos | |
353 | && (level == -1 || bidi_cache[i].resolved_level <= level)) | |
354 | return i; | |
355 | } | |
356 | } | |
357 | ||
358 | return -1; | |
359 | } | |
360 | ||
361 | /* Find a cached state where the resolved level changes to a value | |
362 | that is lower than LEVEL, and return its cache slot index. DIR is | |
363 | the direction to search, starting with the last used cache slot. | |
364 | BEFORE, if non-zero, means return the index of the slot that is | |
365 | ``before'' the level change in the search direction. That is, | |
366 | given the cached levels like this: | |
367 | ||
368 | 1122333442211 | |
369 | AB C | |
370 | ||
371 | and assuming we are at the position cached at the slot marked with | |
372 | C, searching backwards (DIR = -1) for LEVEL = 2 will return the | |
373 | index of slot B or A, depending whether BEFORE is, respectively, | |
374 | non-zero or zero. */ | |
375 | static int | |
376 | bidi_cache_find_level_change (int level, int dir, int before) | |
377 | { | |
378 | if (bidi_cache_idx) | |
379 | { | |
380 | int i = dir ? bidi_cache_last_idx : bidi_cache_idx - 1; | |
381 | int incr = before ? 1 : 0; | |
382 | ||
383 | if (!dir) | |
384 | dir = -1; | |
385 | else if (!incr) | |
386 | i += dir; | |
387 | ||
388 | if (dir < 0) | |
389 | { | |
390 | while (i >= incr) | |
391 | { | |
392 | if (bidi_cache[i - incr].resolved_level >= 0 | |
393 | && bidi_cache[i - incr].resolved_level < level) | |
394 | return i; | |
395 | i--; | |
396 | } | |
397 | } | |
398 | else | |
399 | { | |
400 | while (i < bidi_cache_idx - incr) | |
401 | { | |
402 | if (bidi_cache[i + incr].resolved_level >= 0 | |
403 | && bidi_cache[i + incr].resolved_level < level) | |
404 | return i; | |
405 | i++; | |
406 | } | |
407 | } | |
408 | } | |
409 | ||
410 | return -1; | |
411 | } | |
412 | ||
fd3998ff | 413 | static INLINE void |
b7b65b15 EZ |
414 | bidi_cache_iterator_state (struct bidi_it *bidi_it, int resolved) |
415 | { | |
416 | int idx; | |
417 | ||
418 | /* We should never cache on backward scans. */ | |
419 | if (bidi_it->scan_dir == -1) | |
420 | abort (); | |
421 | idx = bidi_cache_search (bidi_it->charpos, -1, 1); | |
422 | ||
423 | if (idx < 0) | |
424 | { | |
425 | idx = bidi_cache_idx; | |
2fe72643 EZ |
426 | /* Enlarge the cache as needed. */ |
427 | if (idx >= bidi_cache_size) | |
428 | { | |
0416466c | 429 | bidi_cache_size += BIDI_CACHE_CHUNK; |
2fe72643 | 430 | bidi_cache = |
0416466c | 431 | (struct bidi_it *) xrealloc (bidi_cache, bidi_cache_size * elsz); |
2fe72643 | 432 | } |
bd924a5d EZ |
433 | /* Character positions should correspond to cache positions 1:1. |
434 | If we are outside the range of cached positions, the cache is | |
435 | useless and must be reset. */ | |
436 | if (idx > 0 && | |
437 | (bidi_it->charpos > bidi_cache[idx - 1].charpos + 1 | |
438 | || bidi_it->charpos < bidi_cache[0].charpos)) | |
439 | { | |
440 | bidi_cache_reset (); | |
441 | idx = 0; | |
442 | } | |
b7b65b15 EZ |
443 | bidi_copy_it (&bidi_cache[idx], bidi_it); |
444 | if (!resolved) | |
445 | bidi_cache[idx].resolved_level = -1; | |
446 | } | |
447 | else | |
448 | { | |
449 | /* Copy only the members which could have changed, to avoid | |
450 | costly copying of the entire struct. */ | |
451 | bidi_cache[idx].type = bidi_it->type; | |
2d6e4628 | 452 | bidi_check_type (bidi_it->type); |
89d3374a EZ |
453 | bidi_cache[idx].type_after_w1 = bidi_it->type_after_w1; |
454 | bidi_check_type (bidi_it->type_after_w1); | |
b7b65b15 EZ |
455 | if (resolved) |
456 | bidi_cache[idx].resolved_level = bidi_it->resolved_level; | |
457 | else | |
458 | bidi_cache[idx].resolved_level = -1; | |
459 | bidi_cache[idx].invalid_levels = bidi_it->invalid_levels; | |
460 | bidi_cache[idx].invalid_rl_levels = bidi_it->invalid_rl_levels; | |
461 | bidi_cache[idx].next_for_neutral = bidi_it->next_for_neutral; | |
462 | bidi_cache[idx].next_for_ws = bidi_it->next_for_ws; | |
463 | bidi_cache[idx].ignore_bn_limit = bidi_it->ignore_bn_limit; | |
464 | } | |
465 | ||
466 | bidi_cache_last_idx = idx; | |
467 | if (idx >= bidi_cache_idx) | |
468 | bidi_cache_idx = idx + 1; | |
469 | } | |
470 | ||
fd3998ff | 471 | static INLINE bidi_type_t |
b7b65b15 EZ |
472 | bidi_cache_find (int charpos, int level, struct bidi_it *bidi_it) |
473 | { | |
474 | int i = bidi_cache_search (charpos, level, bidi_it->scan_dir); | |
475 | ||
476 | if (i >= 0) | |
477 | { | |
478 | bidi_dir_t current_scan_dir = bidi_it->scan_dir; | |
479 | ||
5009f85e | 480 | bidi_copy_it (bidi_it, &bidi_cache[i]); |
b7b65b15 EZ |
481 | bidi_cache_last_idx = i; |
482 | /* Don't let scan direction from from the cached state override | |
483 | the current scan direction. */ | |
484 | bidi_it->scan_dir = current_scan_dir; | |
485 | return bidi_it->type; | |
486 | } | |
487 | ||
488 | return UNKNOWN_BT; | |
489 | } | |
490 | ||
fd3998ff | 491 | static INLINE int |
b7b65b15 EZ |
492 | bidi_peek_at_next_level (struct bidi_it *bidi_it) |
493 | { | |
494 | if (bidi_cache_idx == 0 || bidi_cache_last_idx == -1) | |
495 | abort (); | |
496 | return bidi_cache[bidi_cache_last_idx + bidi_it->scan_dir].resolved_level; | |
497 | } | |
498 | ||
be39f003 EZ |
499 | /* Check if buffer position CHARPOS/BYTEPOS is the end of a paragraph. |
500 | Value is the non-negative length of the paragraph separator | |
501 | following the buffer position, -1 if position is at the beginning | |
502 | of a new paragraph, or -2 if position is neither at beginning nor | |
503 | at end of a paragraph. */ | |
fd3998ff | 504 | static EMACS_INT |
6bff6497 | 505 | bidi_at_paragraph_end (EMACS_INT charpos, EMACS_INT bytepos) |
b7b65b15 | 506 | { |
b4bf28b7 | 507 | /* FIXME: Why Fbuffer_local_value rather than just Fsymbol_value? */ |
372b7a95 EZ |
508 | Lisp_Object sep_re; |
509 | Lisp_Object start_re; | |
be39f003 EZ |
510 | EMACS_INT val; |
511 | ||
372b7a95 EZ |
512 | sep_re = paragraph_separate_re; |
513 | start_re = paragraph_start_re; | |
be39f003 EZ |
514 | |
515 | val = fast_looking_at (sep_re, charpos, bytepos, ZV, ZV_BYTE, Qnil); | |
516 | if (val < 0) | |
517 | { | |
518 | if (fast_looking_at (start_re, charpos, bytepos, ZV, ZV_BYTE, Qnil) >= 0) | |
519 | val = -1; | |
520 | else | |
521 | val = -2; | |
522 | } | |
b7b65b15 | 523 | |
be39f003 | 524 | return val; |
b7b65b15 EZ |
525 | } |
526 | ||
527 | /* Determine the start-of-run (sor) directional type given the two | |
528 | embedding levels on either side of the run boundary. Also, update | |
529 | the saved info about previously seen characters, since that info is | |
530 | generally valid for a single level run. */ | |
fd3998ff | 531 | static INLINE void |
b7b65b15 EZ |
532 | bidi_set_sor_type (struct bidi_it *bidi_it, int level_before, int level_after) |
533 | { | |
534 | int higher_level = level_before > level_after ? level_before : level_after; | |
535 | ||
536 | /* The prev_was_pdf gork is required for when we have several PDFs | |
537 | in a row. In that case, we want to compute the sor type for the | |
538 | next level run only once: when we see the first PDF. That's | |
539 | because the sor type depends only on the higher of the two levels | |
540 | that we find on the two sides of the level boundary (see UAX#9, | |
541 | clause X10), and so we don't need to know the final embedding | |
542 | level to which we descend after processing all the PDFs. */ | |
e342a24d | 543 | if (!bidi_it->prev_was_pdf || level_before < level_after) |
b7b65b15 EZ |
544 | /* FIXME: should the default sor direction be user selectable? */ |
545 | bidi_it->sor = (higher_level & 1) != 0 ? R2L : L2R; | |
546 | if (level_before > level_after) | |
547 | bidi_it->prev_was_pdf = 1; | |
548 | ||
549 | bidi_it->prev.type = UNKNOWN_BT; | |
89d3374a EZ |
550 | bidi_it->last_strong.type = bidi_it->last_strong.type_after_w1 = |
551 | bidi_it->last_strong.orig_type = UNKNOWN_BT; | |
b7b65b15 EZ |
552 | bidi_it->prev_for_neutral.type = bidi_it->sor == R2L ? STRONG_R : STRONG_L; |
553 | bidi_it->prev_for_neutral.charpos = bidi_it->charpos; | |
554 | bidi_it->prev_for_neutral.bytepos = bidi_it->bytepos; | |
89d3374a EZ |
555 | bidi_it->next_for_neutral.type = bidi_it->next_for_neutral.type_after_w1 = |
556 | bidi_it->next_for_neutral.orig_type = UNKNOWN_BT; | |
b7b65b15 EZ |
557 | bidi_it->ignore_bn_limit = 0; /* meaning it's unknown */ |
558 | } | |
559 | ||
6bff6497 | 560 | static void |
be39f003 EZ |
561 | bidi_line_init (struct bidi_it *bidi_it) |
562 | { | |
563 | bidi_it->scan_dir = 1; /* FIXME: do we need to have control on this? */ | |
564 | bidi_it->resolved_level = bidi_it->level_stack[0].level; | |
565 | bidi_it->level_stack[0].override = NEUTRAL_DIR; /* X1 */ | |
566 | bidi_it->invalid_levels = 0; | |
567 | bidi_it->invalid_rl_levels = -1; | |
568 | bidi_it->next_en_pos = -1; | |
569 | bidi_it->next_for_ws.type = UNKNOWN_BT; | |
b44d9321 EZ |
570 | bidi_set_sor_type (bidi_it, |
571 | bidi_it->paragraph_dir == R2L ? 1 : 0, | |
be39f003 EZ |
572 | bidi_it->level_stack[0].level); /* X10 */ |
573 | ||
574 | bidi_cache_reset (); | |
575 | } | |
576 | ||
577 | /* Find the beginning of this paragraph by looking back in the buffer. | |
578 | Value is the byte position of the paragraph's beginning. */ | |
579 | static EMACS_INT | |
b44d9321 | 580 | bidi_find_paragraph_start (EMACS_INT pos, EMACS_INT pos_byte) |
6bff6497 | 581 | { |
372b7a95 | 582 | Lisp_Object re = paragraph_start_re; |
6bff6497 EZ |
583 | EMACS_INT limit = ZV, limit_byte = ZV_BYTE; |
584 | ||
6bff6497 EZ |
585 | while (pos_byte > BEGV_BYTE |
586 | && fast_looking_at (re, pos, pos_byte, limit, limit_byte, Qnil) < 0) | |
587 | { | |
be39f003 EZ |
588 | pos = find_next_newline_no_quit (pos - 1, -1); |
589 | pos_byte = CHAR_TO_BYTE (pos); | |
6bff6497 | 590 | } |
be39f003 | 591 | return pos_byte; |
6bff6497 EZ |
592 | } |
593 | ||
be39f003 | 594 | /* Determine the direction, a.k.a. base embedding level, of the |
b44d9321 EZ |
595 | paragraph we are about to iterate through. If DIR is either L2R or |
596 | R2L, just use that. Otherwise, determine the paragraph direction | |
597 | from the first strong character of the paragraph. | |
598 | ||
599 | Note that this gives the paragraph separator the same direction as | |
600 | the preceding paragraph, even though Emacs generally views the | |
601 | separartor as not belonging to any paragraph. */ | |
b7b65b15 EZ |
602 | void |
603 | bidi_paragraph_init (bidi_dir_t dir, struct bidi_it *bidi_it) | |
604 | { | |
6bff6497 | 605 | EMACS_INT bytepos = bidi_it->bytepos; |
e7402cb2 | 606 | |
5e65aec0 EZ |
607 | /* Special case for an empty buffer. */ |
608 | if (bytepos == BEGV_BYTE && bytepos == ZV_BYTE) | |
609 | dir = L2R; | |
9c82e145 | 610 | /* We should never be called at EOB or before BEGV. */ |
5e65aec0 | 611 | else if (bytepos >= ZV_BYTE || bytepos < BEGV_BYTE) |
9c82e145 EZ |
612 | abort (); |
613 | ||
be39f003 EZ |
614 | if (dir == L2R) |
615 | { | |
616 | bidi_it->paragraph_dir = L2R; | |
617 | bidi_it->new_paragraph = 0; | |
618 | } | |
619 | else if (dir == R2L) | |
620 | { | |
621 | bidi_it->paragraph_dir = R2L; | |
622 | bidi_it->new_paragraph = 0; | |
623 | } | |
b7b65b15 EZ |
624 | else if (dir == NEUTRAL_DIR) /* P2 */ |
625 | { | |
6bff6497 EZ |
626 | int ch, ch_len; |
627 | EMACS_INT pos; | |
628 | bidi_type_t type; | |
be39f003 | 629 | |
d20e1419 EZ |
630 | if (!bidi_initialized) |
631 | bidi_initialize (); | |
632 | ||
be39f003 EZ |
633 | /* If we are inside a paragraph separator, we are just waiting |
634 | for the separator to be exhausted; use the previous paragraph | |
e5a2fec7 EZ |
635 | direction. But don't do that if we have been just reseated, |
636 | because we need to reinitialize below in that case. */ | |
637 | if (!bidi_it->first_elt | |
638 | && bidi_it->charpos < bidi_it->separator_limit) | |
be39f003 EZ |
639 | return; |
640 | ||
b44d9321 | 641 | /* If we are on a newline, get past it to where the next |
5e65aec0 EZ |
642 | paragraph might start. But don't do that at BEGV since then |
643 | we are potentially in a new paragraph that doesn't yet | |
644 | exist. */ | |
c143c213 | 645 | pos = bidi_it->charpos; |
5e65aec0 | 646 | if (bytepos > BEGV_BYTE && FETCH_CHAR (bytepos) == '\n') |
be39f003 | 647 | { |
b44d9321 | 648 | bytepos++; |
c143c213 | 649 | pos++; |
be39f003 | 650 | } |
b44d9321 EZ |
651 | |
652 | /* We are either at the beginning of a paragraph or in the | |
653 | middle of it. Find where this paragraph starts. */ | |
654 | bytepos = bidi_find_paragraph_start (pos, bytepos); | |
6bff6497 | 655 | |
be39f003 EZ |
656 | bidi_it->separator_limit = -1; |
657 | bidi_it->new_paragraph = 0; | |
6bff6497 EZ |
658 | ch = FETCH_CHAR (bytepos); |
659 | ch_len = CHAR_BYTES (ch); | |
be39f003 | 660 | pos = BYTE_TO_CHAR (bytepos); |
6bff6497 | 661 | type = bidi_get_type (ch, NEUTRAL_DIR); |
b7b65b15 | 662 | |
e342a24d | 663 | for (pos++, bytepos += ch_len; |
b7b65b15 EZ |
664 | /* NOTE: UAX#9 says to search only for L, AL, or R types of |
665 | characters, and ignore RLE, RLO, LRE, and LRO. However, | |
666 | I'm not sure it makes sense to omit those 4; should try | |
667 | with and without that to see the effect. */ | |
668 | (bidi_get_category (type) != STRONG) | |
669 | || (bidi_ignore_explicit_marks_for_paragraph_level | |
670 | && (type == RLE || type == RLO | |
671 | || type == LRE || type == LRO)); | |
6bff6497 | 672 | type = bidi_get_type (ch, NEUTRAL_DIR)) |
b7b65b15 | 673 | { |
be39f003 | 674 | if (type == NEUTRAL_B && bidi_at_paragraph_end (pos, bytepos) >= -1) |
b7b65b15 | 675 | break; |
21fce5ab EZ |
676 | if (bytepos >= ZV_BYTE) |
677 | { | |
678 | /* Pretend there's a paragraph separator at end of buffer. */ | |
679 | type = NEUTRAL_B; | |
680 | break; | |
681 | } | |
b7b65b15 EZ |
682 | FETCH_CHAR_ADVANCE (ch, pos, bytepos); |
683 | } | |
684 | if (type == STRONG_R || type == STRONG_AL) /* P3 */ | |
be39f003 EZ |
685 | bidi_it->paragraph_dir = R2L; |
686 | else if (type == STRONG_L) | |
687 | bidi_it->paragraph_dir = L2R; | |
b7b65b15 | 688 | } |
be39f003 EZ |
689 | else |
690 | abort (); | |
b7b65b15 | 691 | |
b44d9321 EZ |
692 | /* Contrary to UAX#9 clause P3, we only default the paragraph |
693 | direction to L2R if we have no previous usable paragraph | |
694 | direction. */ | |
d20e1419 | 695 | if (bidi_it->paragraph_dir != L2R && bidi_it->paragraph_dir != R2L) |
b44d9321 | 696 | bidi_it->paragraph_dir = L2R; /* P3 and ``higher protocols'' */ |
be39f003 | 697 | if (bidi_it->paragraph_dir == R2L) |
b44d9321 | 698 | bidi_it->level_stack[0].level = 1; |
be39f003 | 699 | else |
b44d9321 | 700 | bidi_it->level_stack[0].level = 0; |
be39f003 EZ |
701 | |
702 | bidi_line_init (bidi_it); | |
b7b65b15 EZ |
703 | } |
704 | ||
6bff6497 EZ |
705 | /* Do whatever UAX#9 clause X8 says should be done at paragraph's |
706 | end. */ | |
fd3998ff | 707 | static INLINE void |
b7b65b15 EZ |
708 | bidi_set_paragraph_end (struct bidi_it *bidi_it) |
709 | { | |
710 | bidi_it->invalid_levels = 0; | |
711 | bidi_it->invalid_rl_levels = -1; | |
712 | bidi_it->stack_idx = 0; | |
713 | bidi_it->resolved_level = bidi_it->level_stack[0].level; | |
b7b65b15 EZ |
714 | } |
715 | ||
89d3374a | 716 | /* Initialize the bidi iterator from buffer position CHARPOS. */ |
b7b65b15 | 717 | void |
6bff6497 | 718 | bidi_init_it (EMACS_INT charpos, EMACS_INT bytepos, struct bidi_it *bidi_it) |
b7b65b15 EZ |
719 | { |
720 | if (! bidi_initialized) | |
721 | bidi_initialize (); | |
89d3374a EZ |
722 | bidi_it->charpos = charpos; |
723 | bidi_it->bytepos = bytepos; | |
6bff6497 EZ |
724 | bidi_it->first_elt = 1; |
725 | bidi_set_paragraph_end (bidi_it); | |
726 | bidi_it->new_paragraph = 1; | |
be39f003 | 727 | bidi_it->separator_limit = -1; |
b7b65b15 | 728 | bidi_it->type = NEUTRAL_B; |
ebb5722e EZ |
729 | bidi_it->type_after_w1 = NEUTRAL_B; |
730 | bidi_it->orig_type = NEUTRAL_B; | |
b7b65b15 | 731 | bidi_it->prev_was_pdf = 0; |
ebb5722e EZ |
732 | bidi_it->prev.type = bidi_it->prev.type_after_w1 = |
733 | bidi_it->prev.orig_type = UNKNOWN_BT; | |
89d3374a EZ |
734 | bidi_it->last_strong.type = bidi_it->last_strong.type_after_w1 = |
735 | bidi_it->last_strong.orig_type = UNKNOWN_BT; | |
b7b65b15 EZ |
736 | bidi_it->next_for_neutral.charpos = -1; |
737 | bidi_it->next_for_neutral.type = | |
89d3374a EZ |
738 | bidi_it->next_for_neutral.type_after_w1 = |
739 | bidi_it->next_for_neutral.orig_type = UNKNOWN_BT; | |
b7b65b15 EZ |
740 | bidi_it->prev_for_neutral.charpos = -1; |
741 | bidi_it->prev_for_neutral.type = | |
89d3374a EZ |
742 | bidi_it->prev_for_neutral.type_after_w1 = |
743 | bidi_it->prev_for_neutral.orig_type = UNKNOWN_BT; | |
b7b65b15 | 744 | bidi_it->sor = L2R; /* FIXME: should it be user-selectable? */ |
2fe72643 | 745 | bidi_cache_shrink (); |
b7b65b15 EZ |
746 | } |
747 | ||
748 | /* Push the current embedding level and override status; reset the | |
749 | current level to LEVEL and the current override status to OVERRIDE. */ | |
fd3998ff | 750 | static INLINE void |
b7b65b15 EZ |
751 | bidi_push_embedding_level (struct bidi_it *bidi_it, |
752 | int level, bidi_dir_t override) | |
753 | { | |
754 | bidi_it->stack_idx++; | |
755 | if (bidi_it->stack_idx >= BIDI_MAXLEVEL) | |
756 | abort (); | |
757 | bidi_it->level_stack[bidi_it->stack_idx].level = level; | |
758 | bidi_it->level_stack[bidi_it->stack_idx].override = override; | |
759 | } | |
760 | ||
761 | /* Pop the embedding level and directional override status from the | |
762 | stack, and return the new level. */ | |
fd3998ff | 763 | static INLINE int |
b7b65b15 EZ |
764 | bidi_pop_embedding_level (struct bidi_it *bidi_it) |
765 | { | |
766 | /* UAX#9 says to ignore invalid PDFs. */ | |
767 | if (bidi_it->stack_idx > 0) | |
768 | bidi_it->stack_idx--; | |
769 | return bidi_it->level_stack[bidi_it->stack_idx].level; | |
770 | } | |
771 | ||
772 | /* Record in SAVED_INFO the information about the current character. */ | |
fd3998ff | 773 | static INLINE void |
b7b65b15 EZ |
774 | bidi_remember_char (struct bidi_saved_info *saved_info, |
775 | struct bidi_it *bidi_it) | |
776 | { | |
777 | saved_info->charpos = bidi_it->charpos; | |
778 | saved_info->bytepos = bidi_it->bytepos; | |
779 | saved_info->type = bidi_it->type; | |
2d6e4628 | 780 | bidi_check_type (bidi_it->type); |
89d3374a EZ |
781 | saved_info->type_after_w1 = bidi_it->type_after_w1; |
782 | bidi_check_type (bidi_it->type_after_w1); | |
b7b65b15 | 783 | saved_info->orig_type = bidi_it->orig_type; |
2d6e4628 | 784 | bidi_check_type (bidi_it->orig_type); |
b7b65b15 EZ |
785 | } |
786 | ||
787 | /* Resolve the type of a neutral character according to the type of | |
788 | surrounding strong text and the current embedding level. */ | |
fd3998ff | 789 | static INLINE bidi_type_t |
b7b65b15 EZ |
790 | bidi_resolve_neutral_1 (bidi_type_t prev_type, bidi_type_t next_type, int lev) |
791 | { | |
792 | /* N1: European and Arabic numbers are treated as though they were R. */ | |
793 | if (next_type == WEAK_EN || next_type == WEAK_AN) | |
794 | next_type = STRONG_R; | |
795 | if (prev_type == WEAK_EN || prev_type == WEAK_AN) | |
796 | prev_type = STRONG_R; | |
797 | ||
798 | if (next_type == prev_type) /* N1 */ | |
799 | return next_type; | |
800 | else if ((lev & 1) == 0) /* N2 */ | |
801 | return STRONG_L; | |
802 | else | |
803 | return STRONG_R; | |
804 | } | |
805 | ||
fd3998ff | 806 | static INLINE int |
b7b65b15 EZ |
807 | bidi_explicit_dir_char (int c) |
808 | { | |
809 | /* FIXME: this should be replaced with a lookup table with suitable | |
810 | bits set, like standard C ctype macros do. */ | |
811 | return (c == LRE_CHAR || c == LRO_CHAR | |
812 | || c == RLE_CHAR || c == RLO_CHAR || c == PDF_CHAR); | |
813 | } | |
814 | ||
815 | /* A helper function for bidi_resolve_explicit. It advances to the | |
816 | next character in logical order and determines the new embedding | |
817 | level and directional override, but does not take into account | |
818 | empty embeddings. */ | |
819 | static int | |
820 | bidi_resolve_explicit_1 (struct bidi_it *bidi_it) | |
821 | { | |
822 | int curchar; | |
823 | bidi_type_t type; | |
824 | int current_level; | |
825 | int new_level; | |
826 | bidi_dir_t override; | |
827 | ||
9c82e145 EZ |
828 | if (bidi_it->bytepos < BEGV_BYTE /* after reseat to BEGV? */ |
829 | || bidi_it->first_elt) | |
e7402cb2 | 830 | { |
9c82e145 EZ |
831 | bidi_it->first_elt = 0; |
832 | if (bidi_it->charpos < BEGV) | |
833 | bidi_it->charpos = BEGV; | |
834 | bidi_it->bytepos = CHAR_TO_BYTE (bidi_it->charpos); | |
e7402cb2 | 835 | } |
9c82e145 | 836 | else if (bidi_it->bytepos < ZV_BYTE) /* don't move at ZV */ |
b7b65b15 EZ |
837 | { |
838 | bidi_it->charpos++; | |
e7402cb2 EZ |
839 | if (bidi_it->ch_len == 0) |
840 | abort (); | |
b7b65b15 EZ |
841 | bidi_it->bytepos += bidi_it->ch_len; |
842 | } | |
843 | ||
844 | current_level = bidi_it->level_stack[bidi_it->stack_idx].level; /* X1 */ | |
845 | override = bidi_it->level_stack[bidi_it->stack_idx].override; | |
846 | new_level = current_level; | |
847 | ||
848 | /* in case it is a unibyte character (not yet implemented) */ | |
849 | /* _fetch_multibyte_char_len = 1; */ | |
e7402cb2 EZ |
850 | if (bidi_it->bytepos >= ZV_BYTE) |
851 | { | |
852 | curchar = BIDI_EOB; | |
853 | bidi_it->ch_len = 1; | |
854 | } | |
855 | else | |
856 | { | |
857 | curchar = FETCH_CHAR (bidi_it->bytepos); | |
858 | bidi_it->ch_len = CHAR_BYTES (curchar); | |
859 | } | |
b7b65b15 | 860 | bidi_it->ch = curchar; |
b7b65b15 | 861 | |
6bff6497 EZ |
862 | /* Don't apply directional override here, as all the types we handle |
863 | below will not be affected by the override anyway, and we need | |
864 | the original type unaltered. The override will be applied in | |
865 | bidi_resolve_weak. */ | |
866 | type = bidi_get_type (curchar, NEUTRAL_DIR); | |
89d3374a EZ |
867 | bidi_it->orig_type = type; |
868 | bidi_check_type (bidi_it->orig_type); | |
b7b65b15 EZ |
869 | |
870 | if (type != PDF) | |
871 | bidi_it->prev_was_pdf = 0; | |
872 | ||
89d3374a | 873 | bidi_it->type_after_w1 = UNKNOWN_BT; |
b7b65b15 EZ |
874 | |
875 | switch (type) | |
876 | { | |
877 | case RLE: /* X2 */ | |
878 | case RLO: /* X4 */ | |
89d3374a EZ |
879 | bidi_it->type_after_w1 = type; |
880 | bidi_check_type (bidi_it->type_after_w1); | |
b7b65b15 EZ |
881 | type = WEAK_BN; /* X9/Retaining */ |
882 | if (bidi_it->ignore_bn_limit <= 0) | |
883 | { | |
884 | if (current_level <= BIDI_MAXLEVEL - 4) | |
885 | { | |
886 | /* Compute the least odd embedding level greater than | |
887 | the current level. */ | |
888 | new_level = ((current_level + 1) & ~1) + 1; | |
89d3374a | 889 | if (bidi_it->type_after_w1 == RLE) |
b7b65b15 EZ |
890 | override = NEUTRAL_DIR; |
891 | else | |
892 | override = R2L; | |
893 | if (current_level == BIDI_MAXLEVEL - 4) | |
894 | bidi_it->invalid_rl_levels = 0; | |
895 | bidi_push_embedding_level (bidi_it, new_level, override); | |
896 | } | |
897 | else | |
898 | { | |
899 | bidi_it->invalid_levels++; | |
900 | /* See the commentary about invalid_rl_levels below. */ | |
901 | if (bidi_it->invalid_rl_levels < 0) | |
902 | bidi_it->invalid_rl_levels = 0; | |
903 | bidi_it->invalid_rl_levels++; | |
904 | } | |
905 | } | |
89d3374a | 906 | else if (bidi_it->prev.type_after_w1 == WEAK_EN /* W5/Retaining */ |
b7b65b15 EZ |
907 | || bidi_it->next_en_pos > bidi_it->charpos) |
908 | type = WEAK_EN; | |
909 | break; | |
910 | case LRE: /* X3 */ | |
911 | case LRO: /* X5 */ | |
89d3374a EZ |
912 | bidi_it->type_after_w1 = type; |
913 | bidi_check_type (bidi_it->type_after_w1); | |
b7b65b15 EZ |
914 | type = WEAK_BN; /* X9/Retaining */ |
915 | if (bidi_it->ignore_bn_limit <= 0) | |
916 | { | |
917 | if (current_level <= BIDI_MAXLEVEL - 5) | |
918 | { | |
919 | /* Compute the least even embedding level greater than | |
920 | the current level. */ | |
921 | new_level = ((current_level + 2) & ~1); | |
89d3374a | 922 | if (bidi_it->type_after_w1 == LRE) |
b7b65b15 EZ |
923 | override = NEUTRAL_DIR; |
924 | else | |
925 | override = L2R; | |
926 | bidi_push_embedding_level (bidi_it, new_level, override); | |
927 | } | |
928 | else | |
929 | { | |
930 | bidi_it->invalid_levels++; | |
931 | /* invalid_rl_levels counts invalid levels encountered | |
932 | while the embedding level was already too high for | |
933 | LRE/LRO, but not for RLE/RLO. That is because | |
934 | there may be exactly one PDF which we should not | |
935 | ignore even though invalid_levels is non-zero. | |
936 | invalid_rl_levels helps to know what PDF is | |
937 | that. */ | |
938 | if (bidi_it->invalid_rl_levels >= 0) | |
939 | bidi_it->invalid_rl_levels++; | |
940 | } | |
941 | } | |
89d3374a | 942 | else if (bidi_it->prev.type_after_w1 == WEAK_EN /* W5/Retaining */ |
b7b65b15 EZ |
943 | || bidi_it->next_en_pos > bidi_it->charpos) |
944 | type = WEAK_EN; | |
945 | break; | |
946 | case PDF: /* X7 */ | |
89d3374a EZ |
947 | bidi_it->type_after_w1 = type; |
948 | bidi_check_type (bidi_it->type_after_w1); | |
b7b65b15 EZ |
949 | type = WEAK_BN; /* X9/Retaining */ |
950 | if (bidi_it->ignore_bn_limit <= 0) | |
951 | { | |
952 | if (!bidi_it->invalid_rl_levels) | |
953 | { | |
954 | new_level = bidi_pop_embedding_level (bidi_it); | |
955 | bidi_it->invalid_rl_levels = -1; | |
956 | if (bidi_it->invalid_levels) | |
957 | bidi_it->invalid_levels--; | |
958 | /* else nothing: UAX#9 says to ignore invalid PDFs */ | |
959 | } | |
960 | if (!bidi_it->invalid_levels) | |
961 | new_level = bidi_pop_embedding_level (bidi_it); | |
962 | else | |
963 | { | |
964 | bidi_it->invalid_levels--; | |
965 | bidi_it->invalid_rl_levels--; | |
966 | } | |
967 | } | |
89d3374a | 968 | else if (bidi_it->prev.type_after_w1 == WEAK_EN /* W5/Retaining */ |
b7b65b15 EZ |
969 | || bidi_it->next_en_pos > bidi_it->charpos) |
970 | type = WEAK_EN; | |
971 | break; | |
972 | default: | |
973 | /* Nothing. */ | |
974 | break; | |
975 | } | |
976 | ||
977 | bidi_it->type = type; | |
2d6e4628 | 978 | bidi_check_type (bidi_it->type); |
b7b65b15 EZ |
979 | |
980 | return new_level; | |
981 | } | |
982 | ||
983 | /* Given an iterator state in BIDI_IT, advance one character position | |
984 | in the buffer to the next character (in the logical order), resolve | |
985 | any explicit embeddings and directional overrides, and return the | |
986 | embedding level of the character after resolving explicit | |
987 | directives and ignoring empty embeddings. */ | |
988 | static int | |
989 | bidi_resolve_explicit (struct bidi_it *bidi_it) | |
990 | { | |
991 | int prev_level = bidi_it->level_stack[bidi_it->stack_idx].level; | |
992 | int new_level = bidi_resolve_explicit_1 (bidi_it); | |
993 | ||
994 | if (prev_level < new_level | |
995 | && bidi_it->type == WEAK_BN | |
996 | && bidi_it->ignore_bn_limit == 0 /* only if not already known */ | |
1502b819 | 997 | && bidi_it->bytepos < ZV_BYTE /* not already at EOB */ |
b7b65b15 EZ |
998 | && bidi_explicit_dir_char (FETCH_CHAR (bidi_it->bytepos |
999 | + bidi_it->ch_len))) | |
1000 | { | |
1001 | /* Avoid pushing and popping embedding levels if the level run | |
1002 | is empty, as this breaks level runs where it shouldn't. | |
1003 | UAX#9 removes all the explicit embedding and override codes, | |
1004 | so empty embeddings disappear without a trace. We need to | |
1005 | behave as if we did the same. */ | |
1006 | struct bidi_it saved_it; | |
1007 | int level = prev_level; | |
1008 | ||
1009 | bidi_copy_it (&saved_it, bidi_it); | |
1010 | ||
1011 | while (bidi_explicit_dir_char (FETCH_CHAR (bidi_it->bytepos | |
1012 | + bidi_it->ch_len))) | |
1013 | { | |
1014 | level = bidi_resolve_explicit_1 (bidi_it); | |
1015 | } | |
1016 | ||
1017 | if (level == prev_level) /* empty embedding */ | |
1018 | saved_it.ignore_bn_limit = bidi_it->charpos + 1; | |
1019 | else /* this embedding is non-empty */ | |
1020 | saved_it.ignore_bn_limit = -1; | |
1021 | ||
1022 | bidi_copy_it (bidi_it, &saved_it); | |
1023 | if (bidi_it->ignore_bn_limit > 0) | |
1024 | { | |
1025 | /* We pushed a level, but we shouldn't have. Undo that. */ | |
1026 | if (!bidi_it->invalid_rl_levels) | |
1027 | { | |
1028 | new_level = bidi_pop_embedding_level (bidi_it); | |
1029 | bidi_it->invalid_rl_levels = -1; | |
1030 | if (bidi_it->invalid_levels) | |
1031 | bidi_it->invalid_levels--; | |
1032 | } | |
1033 | if (!bidi_it->invalid_levels) | |
1034 | new_level = bidi_pop_embedding_level (bidi_it); | |
1035 | else | |
1036 | { | |
1037 | bidi_it->invalid_levels--; | |
1038 | bidi_it->invalid_rl_levels--; | |
1039 | } | |
1040 | } | |
1041 | } | |
1042 | ||
b7b65b15 EZ |
1043 | if (bidi_it->type == NEUTRAL_B) /* X8 */ |
1044 | { | |
21fce5ab | 1045 | bidi_set_paragraph_end (bidi_it); |
6bff6497 EZ |
1046 | /* This is needed by bidi_resolve_weak below, and in L1. */ |
1047 | bidi_it->type_after_w1 = bidi_it->type; | |
89d3374a | 1048 | bidi_check_type (bidi_it->type_after_w1); |
b7b65b15 EZ |
1049 | } |
1050 | ||
1051 | return new_level; | |
1052 | } | |
1053 | ||
1054 | /* Advance in the buffer, resolve weak types and return the type of | |
1055 | the next character after weak type resolution. */ | |
fd3998ff | 1056 | static bidi_type_t |
b7b65b15 EZ |
1057 | bidi_resolve_weak (struct bidi_it *bidi_it) |
1058 | { | |
1059 | bidi_type_t type; | |
1060 | bidi_dir_t override; | |
1061 | int prev_level = bidi_it->level_stack[bidi_it->stack_idx].level; | |
1062 | int new_level = bidi_resolve_explicit (bidi_it); | |
1063 | int next_char; | |
1064 | bidi_type_t type_of_next; | |
1065 | struct bidi_it saved_it; | |
1066 | ||
1067 | type = bidi_it->type; | |
1068 | override = bidi_it->level_stack[bidi_it->stack_idx].override; | |
1069 | ||
1070 | if (type == UNKNOWN_BT | |
1071 | || type == LRE | |
1072 | || type == LRO | |
1073 | || type == RLE | |
1074 | || type == RLO | |
1075 | || type == PDF) | |
1076 | abort (); | |
1077 | ||
1078 | if (new_level != prev_level | |
1079 | || bidi_it->type == NEUTRAL_B) | |
1080 | { | |
1081 | /* We've got a new embedding level run, compute the directional | |
1082 | type of sor and initialize per-run variables (UAX#9, clause | |
1083 | X10). */ | |
1084 | bidi_set_sor_type (bidi_it, prev_level, new_level); | |
1085 | } | |
1086 | else if (type == NEUTRAL_S || type == NEUTRAL_WS | |
1087 | || type == WEAK_BN || type == STRONG_AL) | |
89d3374a EZ |
1088 | bidi_it->type_after_w1 = type; /* needed in L1 */ |
1089 | bidi_check_type (bidi_it->type_after_w1); | |
b7b65b15 EZ |
1090 | |
1091 | /* Level and directional override status are already recorded in | |
1092 | bidi_it, and do not need any change; see X6. */ | |
1093 | if (override == R2L) /* X6 */ | |
1094 | type = STRONG_R; | |
1095 | else if (override == L2R) | |
1096 | type = STRONG_L; | |
bc5a45f3 | 1097 | else |
b7b65b15 | 1098 | { |
bc5a45f3 | 1099 | if (type == WEAK_NSM) /* W1 */ |
b7b65b15 | 1100 | { |
bc5a45f3 | 1101 | /* Note that we don't need to consider the case where the |
5930fe97 EZ |
1102 | prev character has its type overridden by an RLO or LRO, |
1103 | because then either the type of this NSM would have been | |
1104 | also overridden, or the previous character is outside the | |
1105 | current level run, and thus not relevant to this NSM. | |
1106 | This is why NSM gets the type_after_w1 of the previous | |
1107 | character. */ | |
ebb5722e EZ |
1108 | if (bidi_it->prev.type_after_w1 != UNKNOWN_BT |
1109 | /* if type_after_w1 is NEUTRAL_B, this NSM is at sor */ | |
1110 | && bidi_it->prev.type_after_w1 != NEUTRAL_B) | |
5930fe97 | 1111 | type = bidi_it->prev.type_after_w1; |
bc5a45f3 EZ |
1112 | else if (bidi_it->sor == R2L) |
1113 | type = STRONG_R; | |
1114 | else if (bidi_it->sor == L2R) | |
1115 | type = STRONG_L; | |
1116 | else /* shouldn't happen! */ | |
1117 | abort (); | |
b7b65b15 | 1118 | } |
bc5a45f3 EZ |
1119 | if (type == WEAK_EN /* W2 */ |
1120 | && bidi_it->last_strong.type_after_w1 == STRONG_AL) | |
1121 | type = WEAK_AN; | |
1122 | else if (type == STRONG_AL) /* W3 */ | |
1123 | type = STRONG_R; | |
1124 | else if ((type == WEAK_ES /* W4 */ | |
1125 | && bidi_it->prev.type_after_w1 == WEAK_EN | |
1126 | && bidi_it->prev.orig_type == WEAK_EN) | |
1127 | || (type == WEAK_CS | |
1128 | && ((bidi_it->prev.type_after_w1 == WEAK_EN | |
1129 | && bidi_it->prev.orig_type == WEAK_EN) | |
1130 | || bidi_it->prev.type_after_w1 == WEAK_AN))) | |
b7b65b15 | 1131 | { |
e7402cb2 EZ |
1132 | next_char = |
1133 | bidi_it->bytepos + bidi_it->ch_len >= ZV_BYTE | |
1134 | ? BIDI_EOB : FETCH_CHAR (bidi_it->bytepos + bidi_it->ch_len); | |
6bff6497 | 1135 | type_of_next = bidi_get_type (next_char, override); |
b7b65b15 | 1136 | |
bc5a45f3 | 1137 | if (type_of_next == WEAK_BN |
b7b65b15 EZ |
1138 | || bidi_explicit_dir_char (next_char)) |
1139 | { | |
1140 | bidi_copy_it (&saved_it, bidi_it); | |
1141 | while (bidi_resolve_explicit (bidi_it) == new_level | |
bc5a45f3 | 1142 | && bidi_it->type == WEAK_BN) |
b7b65b15 EZ |
1143 | ; |
1144 | type_of_next = bidi_it->type; | |
b7b65b15 EZ |
1145 | bidi_copy_it (bidi_it, &saved_it); |
1146 | } | |
bc5a45f3 EZ |
1147 | |
1148 | /* If the next character is EN, but the last strong-type | |
1149 | character is AL, that next EN will be changed to AN when | |
1150 | we process it in W2 above. So in that case, this ES | |
1151 | should not be changed into EN. */ | |
1152 | if (type == WEAK_ES | |
1153 | && type_of_next == WEAK_EN | |
1154 | && bidi_it->last_strong.type_after_w1 != STRONG_AL) | |
1155 | type = WEAK_EN; | |
1156 | else if (type == WEAK_CS) | |
b7b65b15 | 1157 | { |
bc5a45f3 EZ |
1158 | if (bidi_it->prev.type_after_w1 == WEAK_AN |
1159 | && (type_of_next == WEAK_AN | |
1160 | /* If the next character is EN, but the last | |
1161 | strong-type character is AL, EN will be later | |
1162 | changed to AN when we process it in W2 above. | |
1163 | So in that case, this ES should not be | |
1164 | changed into EN. */ | |
1165 | || (type_of_next == WEAK_EN | |
1166 | && bidi_it->last_strong.type_after_w1 == STRONG_AL))) | |
1167 | type = WEAK_AN; | |
1168 | else if (bidi_it->prev.type_after_w1 == WEAK_EN | |
1169 | && type_of_next == WEAK_EN | |
1170 | && bidi_it->last_strong.type_after_w1 != STRONG_AL) | |
1171 | type = WEAK_EN; | |
1172 | } | |
1173 | } | |
1174 | else if (type == WEAK_ET /* W5: ET with EN before or after it */ | |
1175 | || type == WEAK_BN) /* W5/Retaining */ | |
1176 | { | |
1177 | if (bidi_it->prev.type_after_w1 == WEAK_EN /* ET/BN w/EN before it */ | |
1178 | || bidi_it->next_en_pos > bidi_it->charpos) | |
1179 | type = WEAK_EN; | |
1180 | else /* W5: ET/BN with EN after it. */ | |
1181 | { | |
1182 | EMACS_INT en_pos = bidi_it->charpos + 1; | |
1183 | ||
1184 | next_char = | |
1185 | bidi_it->bytepos + bidi_it->ch_len >= ZV_BYTE | |
1186 | ? BIDI_EOB : FETCH_CHAR (bidi_it->bytepos + bidi_it->ch_len); | |
1187 | type_of_next = bidi_get_type (next_char, override); | |
1188 | ||
1189 | if (type_of_next == WEAK_ET | |
1190 | || type_of_next == WEAK_BN | |
1191 | || bidi_explicit_dir_char (next_char)) | |
1192 | { | |
1193 | bidi_copy_it (&saved_it, bidi_it); | |
1194 | while (bidi_resolve_explicit (bidi_it) == new_level | |
1195 | && (bidi_it->type == WEAK_BN | |
1196 | || bidi_it->type == WEAK_ET)) | |
1197 | ; | |
1198 | type_of_next = bidi_it->type; | |
1199 | en_pos = bidi_it->charpos; | |
1200 | bidi_copy_it (bidi_it, &saved_it); | |
1201 | } | |
1202 | if (type_of_next == WEAK_EN) | |
b7b65b15 | 1203 | { |
bc5a45f3 EZ |
1204 | /* If the last strong character is AL, the EN we've |
1205 | found will become AN when we get to it (W2). */ | |
1206 | if (bidi_it->last_strong.type_after_w1 != STRONG_AL) | |
1207 | { | |
1208 | type = WEAK_EN; | |
1209 | /* Remember this EN position, to speed up processing | |
1210 | of the next ETs. */ | |
1211 | bidi_it->next_en_pos = en_pos; | |
1212 | } | |
1213 | else if (type == WEAK_BN) | |
1214 | type = NEUTRAL_ON; /* W6/Retaining */ | |
b7b65b15 | 1215 | } |
b7b65b15 EZ |
1216 | } |
1217 | } | |
1218 | } | |
1219 | ||
1220 | if (type == WEAK_ES || type == WEAK_ET || type == WEAK_CS /* W6 */ | |
89d3374a EZ |
1221 | || (type == WEAK_BN |
1222 | && (bidi_it->prev.type_after_w1 == WEAK_CS /* W6/Retaining */ | |
1223 | || bidi_it->prev.type_after_w1 == WEAK_ES | |
1224 | || bidi_it->prev.type_after_w1 == WEAK_ET))) | |
b7b65b15 EZ |
1225 | type = NEUTRAL_ON; |
1226 | ||
1227 | /* Store the type we've got so far, before we clobber it with strong | |
1228 | types in W7 and while resolving neutral types. But leave alone | |
1229 | the original types that were recorded above, because we will need | |
1230 | them for the L1 clause. */ | |
89d3374a EZ |
1231 | if (bidi_it->type_after_w1 == UNKNOWN_BT) |
1232 | bidi_it->type_after_w1 = type; | |
1233 | bidi_check_type (bidi_it->type_after_w1); | |
b7b65b15 EZ |
1234 | |
1235 | if (type == WEAK_EN) /* W7 */ | |
1236 | { | |
89d3374a | 1237 | if ((bidi_it->last_strong.type_after_w1 == STRONG_L) |
b7b65b15 EZ |
1238 | || (bidi_it->last_strong.type == UNKNOWN_BT && bidi_it->sor == L2R)) |
1239 | type = STRONG_L; | |
1240 | } | |
1241 | ||
1242 | bidi_it->type = type; | |
2d6e4628 | 1243 | bidi_check_type (bidi_it->type); |
b7b65b15 EZ |
1244 | return type; |
1245 | } | |
1246 | ||
fd3998ff | 1247 | static bidi_type_t |
b7b65b15 EZ |
1248 | bidi_resolve_neutral (struct bidi_it *bidi_it) |
1249 | { | |
1250 | int prev_level = bidi_it->level_stack[bidi_it->stack_idx].level; | |
1251 | bidi_type_t type = bidi_resolve_weak (bidi_it); | |
1252 | int current_level = bidi_it->level_stack[bidi_it->stack_idx].level; | |
1253 | ||
1254 | if (!(type == STRONG_R | |
1255 | || type == STRONG_L | |
1256 | || type == WEAK_BN | |
1257 | || type == WEAK_EN | |
1258 | || type == WEAK_AN | |
1259 | || type == NEUTRAL_B | |
1260 | || type == NEUTRAL_S | |
1261 | || type == NEUTRAL_WS | |
1262 | || type == NEUTRAL_ON)) | |
1263 | abort (); | |
1264 | ||
1265 | if (bidi_get_category (type) == NEUTRAL | |
1266 | || (type == WEAK_BN && prev_level == current_level)) | |
1267 | { | |
1268 | if (bidi_it->next_for_neutral.type != UNKNOWN_BT) | |
1269 | type = bidi_resolve_neutral_1 (bidi_it->prev_for_neutral.type, | |
1270 | bidi_it->next_for_neutral.type, | |
1271 | current_level); | |
1272 | else | |
1273 | { | |
1274 | /* Arrrgh!! The UAX#9 algorithm is too deeply entrenched in | |
1275 | the assumption of batch-style processing; see clauses W4, | |
1276 | W5, and especially N1, which require to look far forward | |
1277 | (as well as back) in the buffer. May the fleas of a | |
1278 | thousand camels infest the armpits of those who design | |
1279 | supposedly general-purpose algorithms by looking at their | |
1280 | own implementations, and fail to consider other possible | |
1281 | implementations! */ | |
1282 | struct bidi_it saved_it; | |
1283 | bidi_type_t next_type; | |
1284 | ||
1285 | if (bidi_it->scan_dir == -1) | |
1286 | abort (); | |
1287 | ||
1288 | bidi_copy_it (&saved_it, bidi_it); | |
1289 | /* Scan the text forward until we find the first non-neutral | |
1290 | character, and then use that to resolve the neutral we | |
1291 | are dealing with now. We also cache the scanned iterator | |
1292 | states, to salvage some of the effort later. */ | |
1293 | bidi_cache_iterator_state (bidi_it, 0); | |
1294 | do { | |
1295 | /* Record the info about the previous character, so that | |
1296 | it will be cached below with this state. */ | |
89d3374a | 1297 | if (bidi_it->type_after_w1 != WEAK_BN /* W1/Retaining */ |
b7b65b15 EZ |
1298 | && bidi_it->type != WEAK_BN) |
1299 | bidi_remember_char (&bidi_it->prev, bidi_it); | |
1300 | type = bidi_resolve_weak (bidi_it); | |
1301 | /* Paragraph separators have their levels fully resolved | |
1302 | at this point, so cache them as resolved. */ | |
1303 | bidi_cache_iterator_state (bidi_it, type == NEUTRAL_B); | |
1304 | /* FIXME: implement L1 here, by testing for a newline and | |
1305 | resetting the level for any sequence of whitespace | |
1306 | characters adjacent to it. */ | |
1307 | } while (!(type == NEUTRAL_B | |
1308 | || (type != WEAK_BN | |
1309 | && bidi_get_category (type) != NEUTRAL) | |
1310 | /* This is all per level run, so stop when we | |
1311 | reach the end of this level run. */ | |
1312 | || bidi_it->level_stack[bidi_it->stack_idx].level != | |
1313 | current_level)); | |
1314 | ||
1315 | bidi_remember_char (&saved_it.next_for_neutral, bidi_it); | |
1316 | ||
1317 | switch (type) | |
1318 | { | |
1319 | case STRONG_L: | |
1320 | case STRONG_R: | |
1321 | case STRONG_AL: | |
1322 | next_type = type; | |
1323 | break; | |
1324 | case WEAK_EN: | |
1325 | case WEAK_AN: | |
1326 | /* N1: ``European and Arabic numbers are treated as | |
1327 | though they were R.'' */ | |
1328 | next_type = STRONG_R; | |
1329 | saved_it.next_for_neutral.type = STRONG_R; | |
1330 | break; | |
1331 | case WEAK_BN: | |
1332 | if (!bidi_explicit_dir_char (bidi_it->ch)) | |
1333 | abort (); /* can't happen: BNs are skipped */ | |
1334 | /* FALLTHROUGH */ | |
1335 | case NEUTRAL_B: | |
1336 | /* Marched all the way to the end of this level run. | |
1337 | We need to use the eor type, whose information is | |
1338 | stored by bidi_set_sor_type in the prev_for_neutral | |
1339 | member. */ | |
1340 | if (saved_it.type != WEAK_BN | |
89d3374a | 1341 | || bidi_get_category (bidi_it->prev.type_after_w1) == NEUTRAL) |
b7b65b15 EZ |
1342 | { |
1343 | next_type = bidi_it->prev_for_neutral.type; | |
1344 | saved_it.next_for_neutral.type = next_type; | |
2d6e4628 | 1345 | bidi_check_type (next_type); |
b7b65b15 EZ |
1346 | } |
1347 | else | |
1348 | { | |
1349 | /* This is a BN which does not adjoin neutrals. | |
1350 | Leave its type alone. */ | |
1351 | bidi_copy_it (bidi_it, &saved_it); | |
1352 | return bidi_it->type; | |
1353 | } | |
1354 | break; | |
1355 | default: | |
1356 | abort (); | |
1357 | } | |
1358 | type = bidi_resolve_neutral_1 (saved_it.prev_for_neutral.type, | |
1359 | next_type, current_level); | |
1360 | saved_it.type = type; | |
2d6e4628 | 1361 | bidi_check_type (type); |
b7b65b15 EZ |
1362 | bidi_copy_it (bidi_it, &saved_it); |
1363 | } | |
1364 | } | |
1365 | return type; | |
1366 | } | |
1367 | ||
1368 | /* Given an iterator state in BIDI_IT, advance one character position | |
1369 | in the buffer to the next character (in the logical order), resolve | |
1370 | the bidi type of that next character, and return that type. */ | |
fd3998ff | 1371 | static bidi_type_t |
b7b65b15 EZ |
1372 | bidi_type_of_next_char (struct bidi_it *bidi_it) |
1373 | { | |
1374 | bidi_type_t type; | |
1375 | ||
1376 | /* This should always be called during a forward scan. */ | |
1377 | if (bidi_it->scan_dir != 1) | |
1378 | abort (); | |
1379 | ||
1380 | /* Reset the limit until which to ignore BNs if we step out of the | |
1381 | area where we found only empty levels. */ | |
1382 | if ((bidi_it->ignore_bn_limit > 0 | |
1383 | && bidi_it->ignore_bn_limit <= bidi_it->charpos) | |
1384 | || (bidi_it->ignore_bn_limit == -1 | |
1385 | && !bidi_explicit_dir_char (bidi_it->ch))) | |
1386 | bidi_it->ignore_bn_limit = 0; | |
1387 | ||
1388 | type = bidi_resolve_neutral (bidi_it); | |
1389 | ||
1390 | return type; | |
1391 | } | |
1392 | ||
1393 | /* Given an iterator state BIDI_IT, advance one character position in | |
1394 | the buffer to the next character (in the logical order), resolve | |
1395 | the embedding and implicit levels of that next character, and | |
1396 | return the resulting level. */ | |
fd3998ff | 1397 | static int |
b7b65b15 EZ |
1398 | bidi_level_of_next_char (struct bidi_it *bidi_it) |
1399 | { | |
1400 | bidi_type_t type; | |
1401 | int level, prev_level = -1; | |
1402 | struct bidi_saved_info next_for_neutral; | |
1403 | ||
1404 | if (bidi_it->scan_dir == 1) | |
1405 | { | |
1406 | /* There's no sense in trying to advance if we hit end of text. */ | |
1502b819 | 1407 | if (bidi_it->bytepos >= ZV_BYTE) |
b7b65b15 EZ |
1408 | return bidi_it->resolved_level; |
1409 | ||
1410 | /* Record the info about the previous character. */ | |
89d3374a | 1411 | if (bidi_it->type_after_w1 != WEAK_BN /* W1/Retaining */ |
b7b65b15 EZ |
1412 | && bidi_it->type != WEAK_BN) |
1413 | bidi_remember_char (&bidi_it->prev, bidi_it); | |
89d3374a EZ |
1414 | if (bidi_it->type_after_w1 == STRONG_R |
1415 | || bidi_it->type_after_w1 == STRONG_L | |
1416 | || bidi_it->type_after_w1 == STRONG_AL) | |
b7b65b15 EZ |
1417 | bidi_remember_char (&bidi_it->last_strong, bidi_it); |
1418 | /* FIXME: it sounds like we don't need both prev and | |
1419 | prev_for_neutral members, but I'm leaving them both for now. */ | |
1420 | if (bidi_it->type == STRONG_R || bidi_it->type == STRONG_L | |
1421 | || bidi_it->type == WEAK_EN || bidi_it->type == WEAK_AN) | |
1422 | bidi_remember_char (&bidi_it->prev_for_neutral, bidi_it); | |
1423 | ||
1424 | /* If we overstepped the characters used for resolving neutrals | |
1425 | and whitespace, invalidate their info in the iterator. */ | |
1426 | if (bidi_it->charpos >= bidi_it->next_for_neutral.charpos) | |
1427 | bidi_it->next_for_neutral.type = UNKNOWN_BT; | |
1428 | if (bidi_it->next_en_pos >= 0 | |
1429 | && bidi_it->charpos >= bidi_it->next_en_pos) | |
1430 | bidi_it->next_en_pos = -1; | |
1431 | if (bidi_it->next_for_ws.type != UNKNOWN_BT | |
1432 | && bidi_it->charpos >= bidi_it->next_for_ws.charpos) | |
1433 | bidi_it->next_for_ws.type = UNKNOWN_BT; | |
1434 | ||
1435 | /* This must be taken before we fill the iterator with the info | |
1436 | about the next char. If we scan backwards, the iterator | |
1437 | state must be already cached, so there's no need to know the | |
1438 | embedding level of the previous character, since we will be | |
1439 | returning to our caller shortly. */ | |
1440 | prev_level = bidi_it->level_stack[bidi_it->stack_idx].level; | |
1441 | } | |
1442 | next_for_neutral = bidi_it->next_for_neutral; | |
1443 | ||
1444 | /* Perhaps it is already cached. */ | |
1445 | type = bidi_cache_find (bidi_it->charpos + bidi_it->scan_dir, -1, bidi_it); | |
1446 | if (type != UNKNOWN_BT) | |
1447 | { | |
1448 | /* Don't lose the information for resolving neutrals! The | |
1449 | cached states could have been cached before their | |
1450 | next_for_neutral member was computed. If we are on our way | |
1451 | forward, we can simply take the info from the previous | |
1452 | state. */ | |
1453 | if (bidi_it->scan_dir == 1 | |
1454 | && bidi_it->next_for_neutral.type == UNKNOWN_BT) | |
1455 | bidi_it->next_for_neutral = next_for_neutral; | |
1456 | ||
1457 | /* If resolved_level is -1, it means this state was cached | |
1458 | before it was completely resolved, so we cannot return | |
1459 | it. */ | |
1460 | if (bidi_it->resolved_level != -1) | |
1461 | return bidi_it->resolved_level; | |
1462 | } | |
1463 | if (bidi_it->scan_dir == -1) | |
1464 | /* If we are going backwards, the iterator state is already cached | |
1465 | from previous scans, and should be fully resolved. */ | |
1466 | abort (); | |
1467 | ||
1468 | if (type == UNKNOWN_BT) | |
1469 | type = bidi_type_of_next_char (bidi_it); | |
1470 | ||
1471 | if (type == NEUTRAL_B) | |
1472 | return bidi_it->resolved_level; | |
1473 | ||
1474 | level = bidi_it->level_stack[bidi_it->stack_idx].level; | |
1475 | if ((bidi_get_category (type) == NEUTRAL /* && type != NEUTRAL_B */) | |
1476 | || (type == WEAK_BN && prev_level == level)) | |
1477 | { | |
1478 | if (bidi_it->next_for_neutral.type == UNKNOWN_BT) | |
1479 | abort (); | |
1480 | ||
1481 | /* If the cached state shows a neutral character, it was not | |
1482 | resolved by bidi_resolve_neutral, so do it now. */ | |
1483 | type = bidi_resolve_neutral_1 (bidi_it->prev_for_neutral.type, | |
1484 | bidi_it->next_for_neutral.type, | |
1485 | level); | |
1486 | } | |
1487 | ||
1488 | if (!(type == STRONG_R | |
1489 | || type == STRONG_L | |
1490 | || type == WEAK_BN | |
1491 | || type == WEAK_EN | |
1492 | || type == WEAK_AN)) | |
1493 | abort (); | |
1494 | bidi_it->type = type; | |
2d6e4628 | 1495 | bidi_check_type (bidi_it->type); |
b7b65b15 EZ |
1496 | |
1497 | /* For L1 below, we need to know, for each WS character, whether | |
1498 | it belongs to a sequence of WS characters preceeding a newline | |
1499 | or a TAB or a paragraph separator. */ | |
89d3374a | 1500 | if (bidi_it->orig_type == NEUTRAL_WS |
b7b65b15 EZ |
1501 | && bidi_it->next_for_ws.type == UNKNOWN_BT) |
1502 | { | |
1503 | int ch; | |
1504 | int clen = bidi_it->ch_len; | |
6bff6497 EZ |
1505 | EMACS_INT bpos = bidi_it->bytepos; |
1506 | EMACS_INT cpos = bidi_it->charpos; | |
b7b65b15 EZ |
1507 | bidi_type_t chtype; |
1508 | ||
1509 | do { | |
1510 | /*_fetch_multibyte_char_len = 1;*/ | |
e7402cb2 | 1511 | ch = bpos + clen >= ZV_BYTE ? BIDI_EOB : FETCH_CHAR (bpos + clen); |
b7b65b15 EZ |
1512 | bpos += clen; |
1513 | cpos++; | |
e7402cb2 EZ |
1514 | clen = (ch == BIDI_EOB ? 1 : CHAR_BYTES (ch)); |
1515 | if (ch == '\n' || ch == BIDI_EOB /* || ch == LINESEP_CHAR */) | |
b7b65b15 EZ |
1516 | chtype = NEUTRAL_B; |
1517 | else | |
6bff6497 | 1518 | chtype = bidi_get_type (ch, NEUTRAL_DIR); |
b7b65b15 EZ |
1519 | } while (chtype == NEUTRAL_WS || chtype == WEAK_BN |
1520 | || bidi_explicit_dir_char (ch)); /* L1/Retaining */ | |
1521 | bidi_it->next_for_ws.type = chtype; | |
2d6e4628 | 1522 | bidi_check_type (bidi_it->next_for_ws.type); |
b7b65b15 EZ |
1523 | bidi_it->next_for_ws.charpos = cpos; |
1524 | bidi_it->next_for_ws.bytepos = bpos; | |
1525 | } | |
1526 | ||
1527 | /* Resolve implicit levels, with a twist: PDFs get the embedding | |
1528 | level of the enbedding they terminate. See below for the | |
1529 | reason. */ | |
89d3374a | 1530 | if (bidi_it->orig_type == PDF |
b7b65b15 EZ |
1531 | /* Don't do this if this formatting code didn't change the |
1532 | embedding level due to invalid or empty embeddings. */ | |
1533 | && prev_level != level) | |
1534 | { | |
1535 | /* Don't look in UAX#9 for the reason for this: it's our own | |
1536 | private quirk. The reason is that we want the formatting | |
1537 | codes to be delivered so that they bracket the text of their | |
1538 | embedding. For example, given the text | |
1539 | ||
1540 | {RLO}teST{PDF} | |
1541 | ||
1542 | we want it to be displayed as | |
1543 | ||
1544 | {RLO}STet{PDF} | |
1545 | ||
1546 | not as | |
1547 | ||
1548 | STet{RLO}{PDF} | |
1549 | ||
1550 | which will result because we bump up the embedding level as | |
1551 | soon as we see the RLO and pop it as soon as we see the PDF, | |
1552 | so RLO itself has the same embedding level as "teST", and | |
1553 | thus would be normally delivered last, just before the PDF. | |
1554 | The switch below fiddles with the level of PDF so that this | |
1555 | ugly side effect does not happen. | |
1556 | ||
1557 | (This is, of course, only important if the formatting codes | |
e7402cb2 EZ |
1558 | are actually displayed, but Emacs does need to display them |
1559 | if the user wants to.) */ | |
b7b65b15 EZ |
1560 | level = prev_level; |
1561 | } | |
89d3374a EZ |
1562 | else if (bidi_it->orig_type == NEUTRAL_B /* L1 */ |
1563 | || bidi_it->orig_type == NEUTRAL_S | |
e7402cb2 EZ |
1564 | || bidi_it->ch == '\n' || bidi_it->ch == BIDI_EOB |
1565 | /* || bidi_it->ch == LINESEP_CHAR */ | |
89d3374a | 1566 | || (bidi_it->orig_type == NEUTRAL_WS |
b7b65b15 EZ |
1567 | && (bidi_it->next_for_ws.type == NEUTRAL_B |
1568 | || bidi_it->next_for_ws.type == NEUTRAL_S))) | |
1569 | level = bidi_it->level_stack[0].level; | |
1570 | else if ((level & 1) == 0) /* I1 */ | |
1571 | { | |
1572 | if (type == STRONG_R) | |
1573 | level++; | |
1574 | else if (type == WEAK_EN || type == WEAK_AN) | |
1575 | level += 2; | |
1576 | } | |
1577 | else /* I2 */ | |
1578 | { | |
1579 | if (type == STRONG_L || type == WEAK_EN || type == WEAK_AN) | |
1580 | level++; | |
1581 | } | |
1582 | ||
1583 | bidi_it->resolved_level = level; | |
1584 | return level; | |
1585 | } | |
1586 | ||
1587 | /* Move to the other edge of a level given by LEVEL. If END_FLAG is | |
1588 | non-zero, we are at the end of a level, and we need to prepare to | |
1589 | resume the scan of the lower level. | |
1590 | ||
1591 | If this level's other edge is cached, we simply jump to it, filling | |
1592 | the iterator structure with the iterator state on the other edge. | |
1593 | Otherwise, we walk the buffer until we come back to the same level | |
1594 | as LEVEL. | |
1595 | ||
1596 | Note: we are not talking here about a ``level run'' in the UAX#9 | |
1597 | sense of the term, but rather about a ``level'' which includes | |
1598 | all the levels higher than it. In other words, given the levels | |
1599 | like this: | |
1600 | ||
1601 | 11111112222222333333334443343222222111111112223322111 | |
1602 | A B C | |
1603 | ||
1604 | and assuming we are at point A scanning left to right, this | |
1605 | function moves to point C, whereas the UAX#9 ``level 2 run'' ends | |
1606 | at point B. */ | |
1607 | static void | |
1608 | bidi_find_other_level_edge (struct bidi_it *bidi_it, int level, int end_flag) | |
1609 | { | |
1610 | int dir = end_flag ? -bidi_it->scan_dir : bidi_it->scan_dir; | |
1611 | int idx; | |
1612 | ||
1613 | /* Try the cache first. */ | |
1614 | if ((idx = bidi_cache_find_level_change (level, dir, end_flag)) >= 0) | |
1615 | bidi_cache_fetch_state (idx, bidi_it); | |
1616 | else | |
1617 | { | |
1618 | int new_level; | |
1619 | ||
1620 | if (end_flag) | |
1621 | abort (); /* if we are at end of level, its edges must be cached */ | |
1622 | ||
1623 | bidi_cache_iterator_state (bidi_it, 1); | |
1624 | do { | |
1625 | new_level = bidi_level_of_next_char (bidi_it); | |
1626 | bidi_cache_iterator_state (bidi_it, 1); | |
1627 | } while (new_level >= level); | |
1628 | } | |
1629 | } | |
1630 | ||
1631 | void | |
4b292a22 | 1632 | bidi_move_to_visually_next (struct bidi_it *bidi_it) |
b7b65b15 EZ |
1633 | { |
1634 | int old_level, new_level, next_level; | |
9c82e145 | 1635 | struct bidi_it sentinel; |
b7b65b15 EZ |
1636 | |
1637 | if (bidi_it->scan_dir == 0) | |
1638 | { | |
1639 | bidi_it->scan_dir = 1; /* default to logical order */ | |
1640 | } | |
1641 | ||
be39f003 EZ |
1642 | /* If we just passed a newline, initialize for the next line. */ |
1643 | if (!bidi_it->first_elt && bidi_it->orig_type == NEUTRAL_B) | |
1644 | bidi_line_init (bidi_it); | |
1645 | ||
6dcfd253 EZ |
1646 | /* Prepare the sentinel iterator state, and cache it. When we bump |
1647 | into it, scanning backwards, we'll know that the last non-base | |
1648 | level is exhausted. */ | |
b7b65b15 | 1649 | if (bidi_cache_idx == 0) |
9c82e145 EZ |
1650 | { |
1651 | bidi_copy_it (&sentinel, bidi_it); | |
1652 | if (bidi_it->first_elt) | |
1653 | { | |
1654 | sentinel.charpos--; /* cached charpos needs to be monotonic */ | |
1655 | sentinel.bytepos--; | |
1656 | sentinel.ch = '\n'; /* doesn't matter, but why not? */ | |
1657 | sentinel.ch_len = 1; | |
1658 | } | |
6dcfd253 | 1659 | bidi_cache_iterator_state (&sentinel, 1); |
9c82e145 | 1660 | } |
b7b65b15 EZ |
1661 | |
1662 | old_level = bidi_it->resolved_level; | |
1663 | new_level = bidi_level_of_next_char (bidi_it); | |
b7b65b15 EZ |
1664 | |
1665 | /* Reordering of resolved levels (clause L2) is implemented by | |
1666 | jumping to the other edge of the level and flipping direction of | |
c0546589 | 1667 | scanning the text whenever we find a level change. */ |
b7b65b15 EZ |
1668 | if (new_level != old_level) |
1669 | { | |
1670 | int ascending = new_level > old_level; | |
1671 | int level_to_search = ascending ? old_level + 1 : old_level; | |
1672 | int incr = ascending ? 1 : -1; | |
1673 | int expected_next_level = old_level + incr; | |
1674 | ||
b7b65b15 EZ |
1675 | /* Jump (or walk) to the other edge of this level. */ |
1676 | bidi_find_other_level_edge (bidi_it, level_to_search, !ascending); | |
1677 | /* Switch scan direction and peek at the next character in the | |
1678 | new direction. */ | |
1679 | bidi_it->scan_dir = -bidi_it->scan_dir; | |
1680 | ||
1681 | /* The following loop handles the case where the resolved level | |
1682 | jumps by more than one. This is typical for numbers inside a | |
1683 | run of text with left-to-right embedding direction, but can | |
1684 | also happen in other situations. In those cases the decision | |
1685 | where to continue after a level change, and in what direction, | |
1686 | is tricky. For example, given a text like below: | |
1687 | ||
1688 | abcdefgh | |
1689 | 11336622 | |
1690 | ||
1691 | (where the numbers below the text show the resolved levels), | |
1692 | the result of reordering according to UAX#9 should be this: | |
1693 | ||
1694 | efdcghba | |
1695 | ||
1696 | This is implemented by the loop below which flips direction | |
1697 | and jumps to the other edge of the level each time it finds | |
1698 | the new level not to be the expected one. The expected level | |
1699 | is always one more or one less than the previous one. */ | |
1700 | next_level = bidi_peek_at_next_level (bidi_it); | |
1701 | while (next_level != expected_next_level) | |
1702 | { | |
1703 | expected_next_level += incr; | |
1704 | level_to_search += incr; | |
1705 | bidi_find_other_level_edge (bidi_it, level_to_search, !ascending); | |
1706 | bidi_it->scan_dir = -bidi_it->scan_dir; | |
1707 | next_level = bidi_peek_at_next_level (bidi_it); | |
1708 | } | |
1709 | ||
1710 | /* Finally, deliver the next character in the new direction. */ | |
1711 | next_level = bidi_level_of_next_char (bidi_it); | |
1712 | } | |
1713 | ||
b44d9321 EZ |
1714 | /* Take note when we have just processed the newline that precedes |
1715 | the end of the paragraph. The next time we are about to be | |
1716 | called, set_iterator_to_next will automatically reinit the | |
1717 | paragraph direction, if needed. We do this at the newline before | |
1718 | the paragraph separator, because the next character might not be | |
1719 | the first character of the next paragraph, due to the bidi | |
c0546589 EZ |
1720 | reordering, whereas we _must_ know the paragraph base direction |
1721 | _before_ we process the paragraph's text, since the base | |
1722 | direction affects the reordering. */ | |
6bff6497 | 1723 | if (bidi_it->scan_dir == 1 |
be39f003 EZ |
1724 | && bidi_it->orig_type == NEUTRAL_B |
1725 | && bidi_it->bytepos < ZV_BYTE) | |
1726 | { | |
1727 | EMACS_INT sep_len = | |
1728 | bidi_at_paragraph_end (bidi_it->charpos + 1, | |
1729 | bidi_it->bytepos + bidi_it->ch_len); | |
1730 | if (sep_len >= 0) | |
1731 | { | |
1732 | bidi_it->new_paragraph = 1; | |
b44d9321 EZ |
1733 | /* Record the buffer position of the last character of the |
1734 | paragraph separator. */ | |
1735 | bidi_it->separator_limit = bidi_it->charpos + 1 + sep_len; | |
be39f003 EZ |
1736 | } |
1737 | } | |
6bff6497 | 1738 | |
b7b65b15 EZ |
1739 | if (bidi_it->scan_dir == 1 && bidi_cache_idx) |
1740 | { | |
1741 | /* If we are at paragraph's base embedding level and beyond the | |
1742 | last cached position, the cache's job is done and we can | |
1743 | discard it. */ | |
1744 | if (bidi_it->resolved_level == bidi_it->level_stack[0].level | |
1745 | && bidi_it->charpos > bidi_cache[bidi_cache_idx - 1].charpos) | |
1746 | bidi_cache_reset (); | |
1747 | /* But as long as we are caching during forward scan, we must | |
1748 | cache each state, or else the cache integrity will be | |
1749 | compromised: it assumes cached states correspond to buffer | |
1750 | positions 1:1. */ | |
1751 | else | |
1752 | bidi_cache_iterator_state (bidi_it, 1); | |
1753 | } | |
1754 | } | |
1755 | ||
1756 | /* This is meant to be called from within the debugger, whenever you | |
1757 | wish to examine the cache contents. */ | |
1758 | void | |
1759 | bidi_dump_cached_states (void) | |
1760 | { | |
1761 | int i; | |
1762 | int ndigits = 1; | |
1763 | ||
1764 | if (bidi_cache_idx == 0) | |
1765 | { | |
1766 | fprintf (stderr, "The cache is empty.\n"); | |
1767 | return; | |
1768 | } | |
1769 | fprintf (stderr, "Total of %d state%s in cache:\n", | |
1770 | bidi_cache_idx, bidi_cache_idx == 1 ? "" : "s"); | |
1771 | ||
1772 | for (i = bidi_cache[bidi_cache_idx - 1].charpos; i > 0; i /= 10) | |
1773 | ndigits++; | |
1774 | fputs ("ch ", stderr); | |
1775 | for (i = 0; i < bidi_cache_idx; i++) | |
1776 | fprintf (stderr, "%*c", ndigits, bidi_cache[i].ch); | |
1777 | fputs ("\n", stderr); | |
1778 | fputs ("lvl ", stderr); | |
1779 | for (i = 0; i < bidi_cache_idx; i++) | |
1780 | fprintf (stderr, "%*d", ndigits, bidi_cache[i].resolved_level); | |
1781 | fputs ("\n", stderr); | |
1782 | fputs ("pos ", stderr); | |
1783 | for (i = 0; i < bidi_cache_idx; i++) | |
1784 | fprintf (stderr, "%*d", ndigits, bidi_cache[i].charpos); | |
1785 | fputs ("\n", stderr); | |
1786 | } |