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cbb09f04 | 1 | /* Low-level bidirectional buffer/string-scanning functions for GNU Emacs. |
ab422c4d PE |
2 | Copyright (C) 2000-2001, 2004-2005, 2009-2013 Free Software |
3 | 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, | |
cbb09f04 | 23 | (UBA) as per UAX#9, a part of the Unicode Standard. |
b7b65b15 EZ |
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 | ||
95e1afc6 | 38 | Two other entry points are bidi_paragraph_init and |
940afb59 EZ |
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 | ||
95e1afc6 EZ |
43 | A few auxiliary entry points are used to initialize the bidi |
44 | iterator for iterating an object (buffer or string), push and pop | |
45 | the bidi iterator state, and save and restore the state of the bidi | |
46 | cache. | |
47 | ||
89d3374a EZ |
48 | If you want to understand the code, you will have to read it |
49 | together with the relevant portions of UAX#9. The comments include | |
50 | references to UAX#9 rules, for that very reason. | |
51 | ||
b7b65b15 EZ |
52 | A note about references to UAX#9 rules: if the reference says |
53 | something like "X9/Retaining", it means that you need to refer to | |
cd1181db | 54 | rule X9 and to its modifications described in the "Implementation |
b7b65b15 EZ |
55 | Notes" section of UAX#9, under "Retaining Format Codes". */ |
56 | ||
b7b65b15 | 57 | #include <config.h> |
b7b65b15 | 58 | #include <stdio.h> |
29e3d8d1 | 59 | |
b7b65b15 | 60 | #include "lisp.h" |
b7b65b15 | 61 | #include "character.h" |
e5560ff7 | 62 | #include "buffer.h" |
b7b65b15 EZ |
63 | #include "dispextern.h" |
64 | ||
2cc21167 | 65 | static bool bidi_initialized = 0; |
b7b65b15 | 66 | |
cbc4fd20 | 67 | static Lisp_Object bidi_type_table, bidi_mirror_table; |
b7b65b15 EZ |
68 | |
69 | #define LRM_CHAR 0x200E | |
70 | #define RLM_CHAR 0x200F | |
b7b65b15 | 71 | #define BIDI_EOB -1 |
b7b65b15 | 72 | |
b7b65b15 EZ |
73 | /* Data type for describing the bidirectional character categories. */ |
74 | typedef enum { | |
75 | UNKNOWN_BC, | |
76 | NEUTRAL, | |
77 | WEAK, | |
78 | STRONG | |
79 | } bidi_category_t; | |
80 | ||
32413314 EZ |
81 | /* UAX#9 says to search only for L, AL, or R types of characters, and |
82 | ignore RLE, RLO, LRE, and LRO, when determining the base paragraph | |
83 | level. Yudit indeed ignores them. This variable is therefore set | |
2cc21167 PE |
84 | by default to ignore them, but clearing it will take them into |
85 | account. */ | |
86 | extern bool bidi_ignore_explicit_marks_for_paragraph_level EXTERNALLY_VISIBLE; | |
87 | bool bidi_ignore_explicit_marks_for_paragraph_level = 1; | |
b7b65b15 | 88 | |
372b7a95 | 89 | static Lisp_Object paragraph_start_re, paragraph_separate_re; |
6bff6497 | 90 | static Lisp_Object Qparagraph_start, Qparagraph_separate; |
b7b65b15 | 91 | |
cbb09f04 EZ |
92 | \f |
93 | /*********************************************************************** | |
94 | Utilities | |
95 | ***********************************************************************/ | |
b7b65b15 | 96 | |
6bff6497 EZ |
97 | /* Return the bidi type of a character CH, subject to the current |
98 | directional OVERRIDE. */ | |
0a99eee1 | 99 | static bidi_type_t |
6bff6497 | 100 | bidi_get_type (int ch, bidi_dir_t override) |
b7b65b15 | 101 | { |
6bff6497 EZ |
102 | bidi_type_t default_type; |
103 | ||
e7402cb2 EZ |
104 | if (ch == BIDI_EOB) |
105 | return NEUTRAL_B; | |
e342a24d | 106 | if (ch < 0 || ch > MAX_CHAR) |
1088b922 | 107 | emacs_abort (); |
6bff6497 EZ |
108 | |
109 | default_type = (bidi_type_t) XINT (CHAR_TABLE_REF (bidi_type_table, ch)); | |
bca633fb EZ |
110 | /* Every valid character code, even those that are unassigned by the |
111 | UCD, have some bidi-class property, according to | |
112 | DerivedBidiClass.txt file. Therefore, if we ever get UNKNOWN_BT | |
113 | (= zero) code from CHAR_TABLE_REF, that's a bug. */ | |
114 | if (default_type == UNKNOWN_BT) | |
1088b922 | 115 | emacs_abort (); |
6bff6497 EZ |
116 | |
117 | if (override == NEUTRAL_DIR) | |
118 | return default_type; | |
119 | ||
120 | switch (default_type) | |
121 | { | |
122 | /* Although UAX#9 does not tell, it doesn't make sense to | |
123 | override NEUTRAL_B and LRM/RLM characters. */ | |
124 | case NEUTRAL_B: | |
125 | case LRE: | |
126 | case LRO: | |
127 | case RLE: | |
128 | case RLO: | |
129 | case PDF: | |
130 | return default_type; | |
131 | default: | |
132 | switch (ch) | |
133 | { | |
134 | case LRM_CHAR: | |
135 | case RLM_CHAR: | |
136 | return default_type; | |
137 | default: | |
138 | if (override == L2R) /* X6 */ | |
139 | return STRONG_L; | |
140 | else if (override == R2L) | |
141 | return STRONG_R; | |
142 | else | |
1088b922 | 143 | emacs_abort (); /* can't happen: handled above */ |
6bff6497 EZ |
144 | } |
145 | } | |
b7b65b15 EZ |
146 | } |
147 | ||
0a99eee1 | 148 | static void |
2d6e4628 EZ |
149 | bidi_check_type (bidi_type_t type) |
150 | { | |
a54e2c05 | 151 | eassert (UNKNOWN_BT <= type && type <= NEUTRAL_ON); |
2d6e4628 EZ |
152 | } |
153 | ||
b7b65b15 | 154 | /* Given a bidi TYPE of a character, return its category. */ |
0a99eee1 | 155 | static bidi_category_t |
b7b65b15 EZ |
156 | bidi_get_category (bidi_type_t type) |
157 | { | |
158 | switch (type) | |
159 | { | |
160 | case UNKNOWN_BT: | |
161 | return UNKNOWN_BC; | |
162 | case STRONG_L: | |
163 | case STRONG_R: | |
164 | case STRONG_AL: | |
165 | case LRE: | |
166 | case LRO: | |
167 | case RLE: | |
168 | case RLO: | |
169 | return STRONG; | |
170 | case PDF: /* ??? really?? */ | |
171 | case WEAK_EN: | |
172 | case WEAK_ES: | |
173 | case WEAK_ET: | |
174 | case WEAK_AN: | |
175 | case WEAK_CS: | |
176 | case WEAK_NSM: | |
177 | case WEAK_BN: | |
178 | return WEAK; | |
179 | case NEUTRAL_B: | |
180 | case NEUTRAL_S: | |
181 | case NEUTRAL_WS: | |
182 | case NEUTRAL_ON: | |
183 | return NEUTRAL; | |
184 | default: | |
1088b922 | 185 | emacs_abort (); |
b7b65b15 EZ |
186 | } |
187 | } | |
188 | ||
a6e8d97c EZ |
189 | /* Return the mirrored character of C, if it has one. If C has no |
190 | mirrored counterpart, return C. | |
191 | Note: The conditions in UAX#9 clause L4 regarding the surrounding | |
192 | context must be tested by the caller. */ | |
b7b65b15 EZ |
193 | int |
194 | bidi_mirror_char (int c) | |
195 | { | |
cbc4fd20 EZ |
196 | Lisp_Object val; |
197 | ||
198 | if (c == BIDI_EOB) | |
199 | return c; | |
200 | if (c < 0 || c > MAX_CHAR) | |
1088b922 | 201 | emacs_abort (); |
b7b65b15 | 202 | |
cbc4fd20 EZ |
203 | val = CHAR_TABLE_REF (bidi_mirror_table, c); |
204 | if (INTEGERP (val)) | |
b7b65b15 | 205 | { |
da92a98c | 206 | int v; |
9e1a06fc | 207 | |
da92a98c PE |
208 | /* When debugging, check before assigning to V, so that the check |
209 | isn't broken by undefined behavior due to int overflow. */ | |
81899c91 | 210 | eassert (CHAR_VALID_P (XINT (val))); |
9e1a06fc | 211 | |
da92a98c PE |
212 | v = XINT (val); |
213 | ||
9e1a06fc EZ |
214 | /* Minimal test we must do in optimized builds, to prevent weird |
215 | crashes further down the road. */ | |
216 | if (v < 0 || v > MAX_CHAR) | |
1088b922 | 217 | emacs_abort (); |
9e1a06fc EZ |
218 | |
219 | return v; | |
b7b65b15 | 220 | } |
cbc4fd20 | 221 | |
b7b65b15 EZ |
222 | return c; |
223 | } | |
224 | ||
cbb09f04 EZ |
225 | /* Determine the start-of-run (sor) directional type given the two |
226 | embedding levels on either side of the run boundary. Also, update | |
227 | the saved info about previously seen characters, since that info is | |
228 | generally valid for a single level run. */ | |
0a99eee1 | 229 | static void |
cbb09f04 EZ |
230 | bidi_set_sor_type (struct bidi_it *bidi_it, int level_before, int level_after) |
231 | { | |
512a289d | 232 | int higher_level = (level_before > level_after ? level_before : level_after); |
cbb09f04 EZ |
233 | |
234 | /* The prev_was_pdf gork is required for when we have several PDFs | |
235 | in a row. In that case, we want to compute the sor type for the | |
236 | next level run only once: when we see the first PDF. That's | |
237 | because the sor type depends only on the higher of the two levels | |
238 | that we find on the two sides of the level boundary (see UAX#9, | |
239 | clause X10), and so we don't need to know the final embedding | |
240 | level to which we descend after processing all the PDFs. */ | |
241 | if (!bidi_it->prev_was_pdf || level_before < level_after) | |
242 | /* FIXME: should the default sor direction be user selectable? */ | |
512a289d | 243 | bidi_it->sor = ((higher_level & 1) != 0 ? R2L : L2R); |
cbb09f04 EZ |
244 | if (level_before > level_after) |
245 | bidi_it->prev_was_pdf = 1; | |
246 | ||
247 | bidi_it->prev.type = UNKNOWN_BT; | |
512a289d RS |
248 | bidi_it->last_strong.type = bidi_it->last_strong.type_after_w1 |
249 | = bidi_it->last_strong.orig_type = UNKNOWN_BT; | |
250 | bidi_it->prev_for_neutral.type = (bidi_it->sor == R2L ? STRONG_R : STRONG_L); | |
cbb09f04 EZ |
251 | bidi_it->prev_for_neutral.charpos = bidi_it->charpos; |
252 | bidi_it->prev_for_neutral.bytepos = bidi_it->bytepos; | |
512a289d RS |
253 | bidi_it->next_for_neutral.type = bidi_it->next_for_neutral.type_after_w1 |
254 | = bidi_it->next_for_neutral.orig_type = UNKNOWN_BT; | |
cbb09f04 EZ |
255 | bidi_it->ignore_bn_limit = -1; /* meaning it's unknown */ |
256 | } | |
257 | ||
258 | /* Push the current embedding level and override status; reset the | |
259 | current level to LEVEL and the current override status to OVERRIDE. */ | |
0a99eee1 | 260 | static void |
cbb09f04 EZ |
261 | bidi_push_embedding_level (struct bidi_it *bidi_it, |
262 | int level, bidi_dir_t override) | |
263 | { | |
264 | bidi_it->stack_idx++; | |
a54e2c05 | 265 | eassert (bidi_it->stack_idx < BIDI_MAXLEVEL); |
cbb09f04 EZ |
266 | bidi_it->level_stack[bidi_it->stack_idx].level = level; |
267 | bidi_it->level_stack[bidi_it->stack_idx].override = override; | |
268 | } | |
269 | ||
270 | /* Pop the embedding level and directional override status from the | |
271 | stack, and return the new level. */ | |
0a99eee1 | 272 | static int |
cbb09f04 EZ |
273 | bidi_pop_embedding_level (struct bidi_it *bidi_it) |
274 | { | |
275 | /* UAX#9 says to ignore invalid PDFs. */ | |
276 | if (bidi_it->stack_idx > 0) | |
277 | bidi_it->stack_idx--; | |
278 | return bidi_it->level_stack[bidi_it->stack_idx].level; | |
279 | } | |
280 | ||
281 | /* Record in SAVED_INFO the information about the current character. */ | |
0a99eee1 | 282 | static void |
cbb09f04 EZ |
283 | bidi_remember_char (struct bidi_saved_info *saved_info, |
284 | struct bidi_it *bidi_it) | |
285 | { | |
286 | saved_info->charpos = bidi_it->charpos; | |
287 | saved_info->bytepos = bidi_it->bytepos; | |
288 | saved_info->type = bidi_it->type; | |
289 | bidi_check_type (bidi_it->type); | |
290 | saved_info->type_after_w1 = bidi_it->type_after_w1; | |
291 | bidi_check_type (bidi_it->type_after_w1); | |
292 | saved_info->orig_type = bidi_it->orig_type; | |
293 | bidi_check_type (bidi_it->orig_type); | |
294 | } | |
295 | ||
b7b65b15 EZ |
296 | /* Copy the bidi iterator from FROM to TO. To save cycles, this only |
297 | copies the part of the level stack that is actually in use. */ | |
0a99eee1 | 298 | static void |
b7b65b15 EZ |
299 | bidi_copy_it (struct bidi_it *to, struct bidi_it *from) |
300 | { | |
05584c31 PE |
301 | /* Copy everything from the start through the active part of |
302 | the level stack. */ | |
303 | memcpy (to, from, | |
304 | (offsetof (struct bidi_it, level_stack[1]) | |
305 | + from->stack_idx * sizeof from->level_stack[0])); | |
b7b65b15 EZ |
306 | } |
307 | ||
cbb09f04 EZ |
308 | \f |
309 | /*********************************************************************** | |
310 | Caching the bidi iterator states | |
311 | ***********************************************************************/ | |
b7b65b15 | 312 | |
2fe72643 EZ |
313 | #define BIDI_CACHE_CHUNK 200 |
314 | static struct bidi_it *bidi_cache; | |
39e378da | 315 | static ptrdiff_t bidi_cache_size = 0; |
ad6042bb | 316 | enum { elsz = sizeof (struct bidi_it) }; |
39e378da PE |
317 | static ptrdiff_t bidi_cache_idx; /* next unused cache slot */ |
318 | static ptrdiff_t bidi_cache_last_idx; /* slot of last cache hit */ | |
319 | static ptrdiff_t bidi_cache_start = 0; /* start of cache for this | |
87e67904 EZ |
320 | "stack" level */ |
321 | ||
bc18e09d PE |
322 | /* 5-slot stack for saving the start of the previous level of the |
323 | cache. xdisp.c maintains a 5-slot stack for its iterator state, | |
324 | and we need the same size of our stack. */ | |
325 | static ptrdiff_t bidi_cache_start_stack[IT_STACK_SIZE]; | |
326 | static int bidi_cache_sp; | |
327 | ||
328 | /* Size of header used by bidi_shelve_cache. */ | |
329 | enum | |
330 | { | |
512a289d RS |
331 | bidi_shelve_header_size |
332 | = (sizeof (bidi_cache_idx) + sizeof (bidi_cache_start_stack) | |
333 | + sizeof (bidi_cache_sp) + sizeof (bidi_cache_start) | |
334 | + sizeof (bidi_cache_last_idx)) | |
bc18e09d PE |
335 | }; |
336 | ||
87e67904 EZ |
337 | /* Reset the cache state to the empty state. We only reset the part |
338 | of the cache relevant to iteration of the current object. Previous | |
339 | objects, which are pushed on the display iterator's stack, are left | |
340 | intact. This is called when the cached information is no more | |
341 | useful for the current iteration, e.g. when we were reseated to a | |
342 | new position on the same object. */ | |
0a99eee1 | 343 | static void |
b7b65b15 EZ |
344 | bidi_cache_reset (void) |
345 | { | |
87e67904 | 346 | bidi_cache_idx = bidi_cache_start; |
b7b65b15 EZ |
347 | bidi_cache_last_idx = -1; |
348 | } | |
349 | ||
87e67904 EZ |
350 | /* Shrink the cache to its minimal size. Called when we init the bidi |
351 | iterator for reordering a buffer or a string that does not come | |
352 | from display properties, because that means all the previously | |
353 | cached info is of no further use. */ | |
0a99eee1 | 354 | static void |
2fe72643 EZ |
355 | bidi_cache_shrink (void) |
356 | { | |
357 | if (bidi_cache_size > BIDI_CACHE_CHUNK) | |
358 | { | |
38182d90 | 359 | bidi_cache = xrealloc (bidi_cache, BIDI_CACHE_CHUNK * elsz); |
51f30bc5 | 360 | bidi_cache_size = BIDI_CACHE_CHUNK; |
2fe72643 EZ |
361 | } |
362 | bidi_cache_reset (); | |
363 | } | |
364 | ||
0a99eee1 | 365 | static void |
39e378da | 366 | bidi_cache_fetch_state (ptrdiff_t idx, struct bidi_it *bidi_it) |
b7b65b15 EZ |
367 | { |
368 | int current_scan_dir = bidi_it->scan_dir; | |
369 | ||
87e67904 | 370 | if (idx < bidi_cache_start || idx >= bidi_cache_idx) |
1088b922 | 371 | emacs_abort (); |
b7b65b15 EZ |
372 | |
373 | bidi_copy_it (bidi_it, &bidi_cache[idx]); | |
374 | bidi_it->scan_dir = current_scan_dir; | |
375 | bidi_cache_last_idx = idx; | |
376 | } | |
377 | ||
378 | /* Find a cached state with a given CHARPOS and resolved embedding | |
379 | level less or equal to LEVEL. if LEVEL is -1, disregard the | |
380 | resolved levels in cached states. DIR, if non-zero, means search | |
381 | in that direction from the last cache hit. */ | |
0a99eee1 | 382 | static ptrdiff_t |
d311d28c | 383 | bidi_cache_search (ptrdiff_t charpos, int level, int dir) |
b7b65b15 | 384 | { |
39e378da | 385 | ptrdiff_t i, i_start; |
b7b65b15 | 386 | |
6eec7596 | 387 | if (bidi_cache_idx > bidi_cache_start) |
b7b65b15 | 388 | { |
6eec7596 EZ |
389 | if (bidi_cache_last_idx == -1) |
390 | bidi_cache_last_idx = bidi_cache_idx - 1; | |
b7b65b15 | 391 | if (charpos < bidi_cache[bidi_cache_last_idx].charpos) |
182ce2d2 EZ |
392 | { |
393 | dir = -1; | |
394 | i_start = bidi_cache_last_idx - 1; | |
395 | } | |
396 | else if (charpos > (bidi_cache[bidi_cache_last_idx].charpos | |
397 | + bidi_cache[bidi_cache_last_idx].nchars - 1)) | |
398 | { | |
399 | dir = 1; | |
400 | i_start = bidi_cache_last_idx + 1; | |
401 | } | |
402 | else if (dir) | |
b7b65b15 EZ |
403 | i_start = bidi_cache_last_idx; |
404 | else | |
405 | { | |
406 | dir = -1; | |
407 | i_start = bidi_cache_idx - 1; | |
408 | } | |
409 | ||
410 | if (dir < 0) | |
411 | { | |
412 | /* Linear search for now; FIXME! */ | |
87e67904 | 413 | for (i = i_start; i >= bidi_cache_start; i--) |
182ce2d2 EZ |
414 | if (bidi_cache[i].charpos <= charpos |
415 | && charpos < bidi_cache[i].charpos + bidi_cache[i].nchars | |
b7b65b15 EZ |
416 | && (level == -1 || bidi_cache[i].resolved_level <= level)) |
417 | return i; | |
418 | } | |
419 | else | |
420 | { | |
421 | for (i = i_start; i < bidi_cache_idx; i++) | |
182ce2d2 EZ |
422 | if (bidi_cache[i].charpos <= charpos |
423 | && charpos < bidi_cache[i].charpos + bidi_cache[i].nchars | |
b7b65b15 EZ |
424 | && (level == -1 || bidi_cache[i].resolved_level <= level)) |
425 | return i; | |
426 | } | |
427 | } | |
428 | ||
429 | return -1; | |
430 | } | |
431 | ||
432 | /* Find a cached state where the resolved level changes to a value | |
433 | that is lower than LEVEL, and return its cache slot index. DIR is | |
434 | the direction to search, starting with the last used cache slot. | |
87e67904 | 435 | If DIR is zero, we search backwards from the last occupied cache |
2cc21167 | 436 | slot. BEFORE means return the index of the slot that |
87e67904 | 437 | is ``before'' the level change in the search direction. That is, |
b7b65b15 EZ |
438 | given the cached levels like this: |
439 | ||
440 | 1122333442211 | |
441 | AB C | |
442 | ||
443 | and assuming we are at the position cached at the slot marked with | |
444 | C, searching backwards (DIR = -1) for LEVEL = 2 will return the | |
445 | index of slot B or A, depending whether BEFORE is, respectively, | |
2cc21167 | 446 | true or false. */ |
39e378da | 447 | static ptrdiff_t |
2cc21167 | 448 | bidi_cache_find_level_change (int level, int dir, bool before) |
b7b65b15 EZ |
449 | { |
450 | if (bidi_cache_idx) | |
451 | { | |
39e378da | 452 | ptrdiff_t i = dir ? bidi_cache_last_idx : bidi_cache_idx - 1; |
b7b65b15 EZ |
453 | int incr = before ? 1 : 0; |
454 | ||
a54e2c05 | 455 | eassert (!dir || bidi_cache_last_idx >= 0); |
6eec7596 | 456 | |
b7b65b15 EZ |
457 | if (!dir) |
458 | dir = -1; | |
459 | else if (!incr) | |
460 | i += dir; | |
461 | ||
462 | if (dir < 0) | |
463 | { | |
87e67904 | 464 | while (i >= bidi_cache_start + incr) |
b7b65b15 EZ |
465 | { |
466 | if (bidi_cache[i - incr].resolved_level >= 0 | |
467 | && bidi_cache[i - incr].resolved_level < level) | |
468 | return i; | |
469 | i--; | |
470 | } | |
471 | } | |
472 | else | |
473 | { | |
474 | while (i < bidi_cache_idx - incr) | |
475 | { | |
476 | if (bidi_cache[i + incr].resolved_level >= 0 | |
477 | && bidi_cache[i + incr].resolved_level < level) | |
478 | return i; | |
479 | i++; | |
480 | } | |
481 | } | |
482 | } | |
483 | ||
484 | return -1; | |
485 | } | |
486 | ||
0a99eee1 | 487 | static void |
39e378da | 488 | bidi_cache_ensure_space (ptrdiff_t idx) |
58b9f433 EZ |
489 | { |
490 | /* Enlarge the cache as needed. */ | |
491 | if (idx >= bidi_cache_size) | |
492 | { | |
f0eb61e9 PE |
493 | /* The bidi cache cannot be larger than the largest Lisp string |
494 | or buffer. */ | |
512a289d RS |
495 | ptrdiff_t string_or_buffer_bound |
496 | = max (BUF_BYTES_MAX, STRING_BYTES_BOUND); | |
f0eb61e9 PE |
497 | |
498 | /* Also, it cannot be larger than what C can represent. */ | |
512a289d RS |
499 | ptrdiff_t c_bound |
500 | = (min (PTRDIFF_MAX, SIZE_MAX) - bidi_shelve_header_size) / elsz; | |
f0eb61e9 | 501 | |
512a289d RS |
502 | bidi_cache |
503 | = xpalloc (bidi_cache, &bidi_cache_size, | |
504 | max (BIDI_CACHE_CHUNK, idx - bidi_cache_size + 1), | |
505 | min (string_or_buffer_bound, c_bound), elsz); | |
58b9f433 EZ |
506 | } |
507 | } | |
508 | ||
0a99eee1 | 509 | static void |
2cc21167 | 510 | bidi_cache_iterator_state (struct bidi_it *bidi_it, bool resolved) |
b7b65b15 | 511 | { |
39e378da | 512 | ptrdiff_t idx; |
b7b65b15 EZ |
513 | |
514 | /* We should never cache on backward scans. */ | |
515 | if (bidi_it->scan_dir == -1) | |
1088b922 | 516 | emacs_abort (); |
b7b65b15 EZ |
517 | idx = bidi_cache_search (bidi_it->charpos, -1, 1); |
518 | ||
519 | if (idx < 0) | |
520 | { | |
521 | idx = bidi_cache_idx; | |
58b9f433 | 522 | bidi_cache_ensure_space (idx); |
bd924a5d EZ |
523 | /* Character positions should correspond to cache positions 1:1. |
524 | If we are outside the range of cached positions, the cache is | |
525 | useless and must be reset. */ | |
87e67904 | 526 | if (idx > bidi_cache_start && |
182ce2d2 EZ |
527 | (bidi_it->charpos > (bidi_cache[idx - 1].charpos |
528 | + bidi_cache[idx - 1].nchars) | |
a1344e7d | 529 | || bidi_it->charpos < bidi_cache[bidi_cache_start].charpos)) |
bd924a5d EZ |
530 | { |
531 | bidi_cache_reset (); | |
87e67904 | 532 | idx = bidi_cache_start; |
bd924a5d | 533 | } |
102ebb00 | 534 | if (bidi_it->nchars <= 0) |
1088b922 | 535 | emacs_abort (); |
b7b65b15 EZ |
536 | bidi_copy_it (&bidi_cache[idx], bidi_it); |
537 | if (!resolved) | |
538 | bidi_cache[idx].resolved_level = -1; | |
539 | } | |
540 | else | |
541 | { | |
542 | /* Copy only the members which could have changed, to avoid | |
543 | costly copying of the entire struct. */ | |
544 | bidi_cache[idx].type = bidi_it->type; | |
2d6e4628 | 545 | bidi_check_type (bidi_it->type); |
89d3374a EZ |
546 | bidi_cache[idx].type_after_w1 = bidi_it->type_after_w1; |
547 | bidi_check_type (bidi_it->type_after_w1); | |
b7b65b15 EZ |
548 | if (resolved) |
549 | bidi_cache[idx].resolved_level = bidi_it->resolved_level; | |
550 | else | |
551 | bidi_cache[idx].resolved_level = -1; | |
552 | bidi_cache[idx].invalid_levels = bidi_it->invalid_levels; | |
553 | bidi_cache[idx].invalid_rl_levels = bidi_it->invalid_rl_levels; | |
554 | bidi_cache[idx].next_for_neutral = bidi_it->next_for_neutral; | |
555 | bidi_cache[idx].next_for_ws = bidi_it->next_for_ws; | |
556 | bidi_cache[idx].ignore_bn_limit = bidi_it->ignore_bn_limit; | |
f67cdd7f | 557 | bidi_cache[idx].disp_pos = bidi_it->disp_pos; |
0c95fcf7 | 558 | bidi_cache[idx].disp_prop = bidi_it->disp_prop; |
b7b65b15 EZ |
559 | } |
560 | ||
561 | bidi_cache_last_idx = idx; | |
562 | if (idx >= bidi_cache_idx) | |
563 | bidi_cache_idx = idx + 1; | |
564 | } | |
565 | ||
0a99eee1 | 566 | static bidi_type_t |
d311d28c | 567 | bidi_cache_find (ptrdiff_t charpos, int level, struct bidi_it *bidi_it) |
b7b65b15 | 568 | { |
39e378da | 569 | ptrdiff_t i = bidi_cache_search (charpos, level, bidi_it->scan_dir); |
b7b65b15 | 570 | |
87e67904 | 571 | if (i >= bidi_cache_start) |
b7b65b15 EZ |
572 | { |
573 | bidi_dir_t current_scan_dir = bidi_it->scan_dir; | |
574 | ||
5009f85e | 575 | bidi_copy_it (bidi_it, &bidi_cache[i]); |
b7b65b15 | 576 | bidi_cache_last_idx = i; |
5a5fa834 | 577 | /* Don't let scan direction from the cached state override |
b7b65b15 EZ |
578 | the current scan direction. */ |
579 | bidi_it->scan_dir = current_scan_dir; | |
580 | return bidi_it->type; | |
581 | } | |
582 | ||
583 | return UNKNOWN_BT; | |
584 | } | |
585 | ||
0a99eee1 | 586 | static int |
b7b65b15 EZ |
587 | bidi_peek_at_next_level (struct bidi_it *bidi_it) |
588 | { | |
87e67904 | 589 | if (bidi_cache_idx == bidi_cache_start || bidi_cache_last_idx == -1) |
1088b922 | 590 | emacs_abort (); |
b7b65b15 EZ |
591 | return bidi_cache[bidi_cache_last_idx + bidi_it->scan_dir].resolved_level; |
592 | } | |
593 | ||
cbb09f04 | 594 | \f |
58b9f433 EZ |
595 | /*********************************************************************** |
596 | Pushing and popping the bidi iterator state | |
597 | ***********************************************************************/ | |
58b9f433 EZ |
598 | |
599 | /* Push the bidi iterator state in preparation for reordering a | |
600 | different object, e.g. display string found at certain buffer | |
7e2ad32c EZ |
601 | position. Pushing the bidi iterator boils down to saving its |
602 | entire state on the cache and starting a new cache "stacked" on top | |
603 | of the current cache. */ | |
58b9f433 EZ |
604 | void |
605 | bidi_push_it (struct bidi_it *bidi_it) | |
b7b65b15 | 606 | { |
58b9f433 EZ |
607 | /* Save the current iterator state in its entirety after the last |
608 | used cache slot. */ | |
609 | bidi_cache_ensure_space (bidi_cache_idx); | |
ae1d87e2 | 610 | bidi_cache[bidi_cache_idx++] = *bidi_it; |
be39f003 | 611 | |
58b9f433 | 612 | /* Push the current cache start onto the stack. */ |
a54e2c05 | 613 | eassert (bidi_cache_sp < IT_STACK_SIZE); |
58b9f433 | 614 | bidi_cache_start_stack[bidi_cache_sp++] = bidi_cache_start; |
be39f003 | 615 | |
58b9f433 EZ |
616 | /* Start a new level of cache, and make it empty. */ |
617 | bidi_cache_start = bidi_cache_idx; | |
618 | bidi_cache_last_idx = -1; | |
619 | } | |
620 | ||
621 | /* Restore the iterator state saved by bidi_push_it and return the | |
622 | cache to the corresponding state. */ | |
623 | void | |
624 | bidi_pop_it (struct bidi_it *bidi_it) | |
625 | { | |
626 | if (bidi_cache_start <= 0) | |
1088b922 | 627 | emacs_abort (); |
58b9f433 EZ |
628 | |
629 | /* Reset the next free cache slot index to what it was before the | |
630 | call to bidi_push_it. */ | |
631 | bidi_cache_idx = bidi_cache_start - 1; | |
632 | ||
633 | /* Restore the bidi iterator state saved in the cache. */ | |
ae1d87e2 | 634 | *bidi_it = bidi_cache[bidi_cache_idx]; |
58b9f433 EZ |
635 | |
636 | /* Pop the previous cache start from the stack. */ | |
637 | if (bidi_cache_sp <= 0) | |
1088b922 | 638 | emacs_abort (); |
58b9f433 EZ |
639 | bidi_cache_start = bidi_cache_start_stack[--bidi_cache_sp]; |
640 | ||
641 | /* Invalidate the last-used cache slot data. */ | |
642 | bidi_cache_last_idx = -1; | |
643 | } | |
644 | ||
ec7cc85b | 645 | static ptrdiff_t bidi_cache_total_alloc; |
35928349 | 646 | |
ed94e6d7 EZ |
647 | /* Stash away a copy of the cache and its control variables. */ |
648 | void * | |
649 | bidi_shelve_cache (void) | |
650 | { | |
651 | unsigned char *databuf; | |
458bfed3 | 652 | ptrdiff_t alloc; |
ed94e6d7 | 653 | |
35928349 | 654 | /* Empty cache. */ |
ed94e6d7 EZ |
655 | if (bidi_cache_idx == 0) |
656 | return NULL; | |
657 | ||
458bfed3 PE |
658 | alloc = (bidi_shelve_header_size |
659 | + bidi_cache_idx * sizeof (struct bidi_it)); | |
660 | databuf = xmalloc (alloc); | |
661 | bidi_cache_total_alloc += alloc; | |
35928349 | 662 | |
ed94e6d7 EZ |
663 | memcpy (databuf, &bidi_cache_idx, sizeof (bidi_cache_idx)); |
664 | memcpy (databuf + sizeof (bidi_cache_idx), | |
665 | bidi_cache, bidi_cache_idx * sizeof (struct bidi_it)); | |
666 | memcpy (databuf + sizeof (bidi_cache_idx) | |
667 | + bidi_cache_idx * sizeof (struct bidi_it), | |
668 | bidi_cache_start_stack, sizeof (bidi_cache_start_stack)); | |
669 | memcpy (databuf + sizeof (bidi_cache_idx) | |
670 | + bidi_cache_idx * sizeof (struct bidi_it) | |
671 | + sizeof (bidi_cache_start_stack), | |
672 | &bidi_cache_sp, sizeof (bidi_cache_sp)); | |
673 | memcpy (databuf + sizeof (bidi_cache_idx) | |
674 | + bidi_cache_idx * sizeof (struct bidi_it) | |
675 | + sizeof (bidi_cache_start_stack) + sizeof (bidi_cache_sp), | |
676 | &bidi_cache_start, sizeof (bidi_cache_start)); | |
677 | memcpy (databuf + sizeof (bidi_cache_idx) | |
678 | + bidi_cache_idx * sizeof (struct bidi_it) | |
679 | + sizeof (bidi_cache_start_stack) + sizeof (bidi_cache_sp) | |
680 | + sizeof (bidi_cache_start), | |
681 | &bidi_cache_last_idx, sizeof (bidi_cache_last_idx)); | |
682 | ||
683 | return databuf; | |
684 | } | |
685 | ||
d1410150 EZ |
686 | /* Restore the cache state from a copy stashed away by |
687 | bidi_shelve_cache, and free the buffer used to stash that copy. | |
2cc21167 | 688 | JUST_FREE means free the buffer, but don't restore the |
d1410150 EZ |
689 | cache; used when the corresponding iterator is discarded instead of |
690 | being restored. */ | |
ed94e6d7 | 691 | void |
2cc21167 | 692 | bidi_unshelve_cache (void *databuf, bool just_free) |
ed94e6d7 EZ |
693 | { |
694 | unsigned char *p = databuf; | |
695 | ||
696 | if (!p) | |
be39f003 | 697 | { |
d1410150 EZ |
698 | if (!just_free) |
699 | { | |
700 | /* A NULL pointer means an empty cache. */ | |
701 | bidi_cache_start = 0; | |
702 | bidi_cache_sp = 0; | |
703 | bidi_cache_reset (); | |
704 | } | |
be39f003 | 705 | } |
ed94e6d7 EZ |
706 | else |
707 | { | |
35928349 EZ |
708 | if (just_free) |
709 | { | |
710 | ptrdiff_t idx; | |
711 | ||
712 | memcpy (&idx, p, sizeof (bidi_cache_idx)); | |
512a289d RS |
713 | bidi_cache_total_alloc |
714 | -= bidi_shelve_header_size + idx * sizeof (struct bidi_it); | |
35928349 EZ |
715 | } |
716 | else | |
717 | { | |
718 | memcpy (&bidi_cache_idx, p, sizeof (bidi_cache_idx)); | |
719 | bidi_cache_ensure_space (bidi_cache_idx); | |
720 | memcpy (bidi_cache, p + sizeof (bidi_cache_idx), | |
721 | bidi_cache_idx * sizeof (struct bidi_it)); | |
722 | memcpy (bidi_cache_start_stack, | |
723 | p + sizeof (bidi_cache_idx) | |
724 | + bidi_cache_idx * sizeof (struct bidi_it), | |
725 | sizeof (bidi_cache_start_stack)); | |
726 | memcpy (&bidi_cache_sp, | |
727 | p + sizeof (bidi_cache_idx) | |
728 | + bidi_cache_idx * sizeof (struct bidi_it) | |
729 | + sizeof (bidi_cache_start_stack), | |
730 | sizeof (bidi_cache_sp)); | |
731 | memcpy (&bidi_cache_start, | |
732 | p + sizeof (bidi_cache_idx) | |
733 | + bidi_cache_idx * sizeof (struct bidi_it) | |
734 | + sizeof (bidi_cache_start_stack) + sizeof (bidi_cache_sp), | |
735 | sizeof (bidi_cache_start)); | |
736 | memcpy (&bidi_cache_last_idx, | |
737 | p + sizeof (bidi_cache_idx) | |
738 | + bidi_cache_idx * sizeof (struct bidi_it) | |
739 | + sizeof (bidi_cache_start_stack) + sizeof (bidi_cache_sp) | |
740 | + sizeof (bidi_cache_start), | |
741 | sizeof (bidi_cache_last_idx)); | |
512a289d RS |
742 | bidi_cache_total_alloc |
743 | -= (bidi_shelve_header_size | |
744 | + bidi_cache_idx * sizeof (struct bidi_it)); | |
35928349 | 745 | } |
ed94e6d7 EZ |
746 | |
747 | xfree (p); | |
748 | } | |
749 | } | |
b7b65b15 | 750 | |
58b9f433 | 751 | \f |
cbb09f04 EZ |
752 | /*********************************************************************** |
753 | Initialization | |
754 | ***********************************************************************/ | |
755 | static void | |
756 | bidi_initialize (void) | |
b7b65b15 | 757 | { |
474a8465 EZ |
758 | bidi_type_table = uniprop_table (intern ("bidi-class")); |
759 | if (NILP (bidi_type_table)) | |
1088b922 | 760 | emacs_abort (); |
cbb09f04 EZ |
761 | staticpro (&bidi_type_table); |
762 | ||
474a8465 EZ |
763 | bidi_mirror_table = uniprop_table (intern ("mirroring")); |
764 | if (NILP (bidi_mirror_table)) | |
1088b922 | 765 | emacs_abort (); |
cbb09f04 EZ |
766 | staticpro (&bidi_mirror_table); |
767 | ||
cbb09f04 EZ |
768 | Qparagraph_start = intern ("paragraph-start"); |
769 | staticpro (&Qparagraph_start); | |
770 | paragraph_start_re = Fsymbol_value (Qparagraph_start); | |
771 | if (!STRINGP (paragraph_start_re)) | |
772 | paragraph_start_re = build_string ("\f\\|[ \t]*$"); | |
773 | staticpro (¶graph_start_re); | |
774 | Qparagraph_separate = intern ("paragraph-separate"); | |
775 | staticpro (&Qparagraph_separate); | |
776 | paragraph_separate_re = Fsymbol_value (Qparagraph_separate); | |
777 | if (!STRINGP (paragraph_separate_re)) | |
778 | paragraph_separate_re = build_string ("[ \t\f]*$"); | |
779 | staticpro (¶graph_separate_re); | |
58b9f433 EZ |
780 | |
781 | bidi_cache_sp = 0; | |
ec7cc85b | 782 | bidi_cache_total_alloc = 0; |
58b9f433 | 783 | |
cbb09f04 | 784 | bidi_initialized = 1; |
b7b65b15 EZ |
785 | } |
786 | ||
cbb09f04 EZ |
787 | /* Do whatever UAX#9 clause X8 says should be done at paragraph's |
788 | end. */ | |
0a99eee1 | 789 | static void |
cbb09f04 | 790 | bidi_set_paragraph_end (struct bidi_it *bidi_it) |
b7b65b15 | 791 | { |
cbb09f04 EZ |
792 | bidi_it->invalid_levels = 0; |
793 | bidi_it->invalid_rl_levels = -1; | |
794 | bidi_it->stack_idx = 0; | |
795 | bidi_it->resolved_level = bidi_it->level_stack[0].level; | |
796 | } | |
b7b65b15 | 797 | |
cbb09f04 EZ |
798 | /* Initialize the bidi iterator from buffer/string position CHARPOS. */ |
799 | void | |
2cc21167 | 800 | bidi_init_it (ptrdiff_t charpos, ptrdiff_t bytepos, bool frame_window_p, |
cbb09f04 EZ |
801 | struct bidi_it *bidi_it) |
802 | { | |
803 | if (! bidi_initialized) | |
804 | bidi_initialize (); | |
805 | if (charpos >= 0) | |
806 | bidi_it->charpos = charpos; | |
807 | if (bytepos >= 0) | |
808 | bidi_it->bytepos = bytepos; | |
809 | bidi_it->frame_window_p = frame_window_p; | |
810 | bidi_it->nchars = -1; /* to be computed in bidi_resolve_explicit_1 */ | |
811 | bidi_it->first_elt = 1; | |
812 | bidi_set_paragraph_end (bidi_it); | |
813 | bidi_it->new_paragraph = 1; | |
814 | bidi_it->separator_limit = -1; | |
815 | bidi_it->type = NEUTRAL_B; | |
816 | bidi_it->type_after_w1 = NEUTRAL_B; | |
817 | bidi_it->orig_type = NEUTRAL_B; | |
818 | bidi_it->prev_was_pdf = 0; | |
512a289d RS |
819 | bidi_it->prev.type = bidi_it->prev.type_after_w1 |
820 | = bidi_it->prev.orig_type = UNKNOWN_BT; | |
821 | bidi_it->last_strong.type = bidi_it->last_strong.type_after_w1 | |
822 | = bidi_it->last_strong.orig_type = UNKNOWN_BT; | |
cbb09f04 | 823 | bidi_it->next_for_neutral.charpos = -1; |
512a289d RS |
824 | bidi_it->next_for_neutral.type |
825 | = bidi_it->next_for_neutral.type_after_w1 | |
826 | = bidi_it->next_for_neutral.orig_type = UNKNOWN_BT; | |
cbb09f04 | 827 | bidi_it->prev_for_neutral.charpos = -1; |
512a289d RS |
828 | bidi_it->prev_for_neutral.type |
829 | = bidi_it->prev_for_neutral.type_after_w1 | |
830 | = bidi_it->prev_for_neutral.orig_type = UNKNOWN_BT; | |
cbb09f04 EZ |
831 | bidi_it->sor = L2R; /* FIXME: should it be user-selectable? */ |
832 | bidi_it->disp_pos = -1; /* invalid/unknown */ | |
0c95fcf7 | 833 | bidi_it->disp_prop = 0; |
cbb09f04 EZ |
834 | /* We can only shrink the cache if we are at the bottom level of its |
835 | "stack". */ | |
836 | if (bidi_cache_start == 0) | |
837 | bidi_cache_shrink (); | |
58b9f433 EZ |
838 | else |
839 | bidi_cache_reset (); | |
b7b65b15 EZ |
840 | } |
841 | ||
182ce2d2 | 842 | /* Perform initializations for reordering a new line of bidi text. */ |
6bff6497 | 843 | static void |
be39f003 EZ |
844 | bidi_line_init (struct bidi_it *bidi_it) |
845 | { | |
846 | bidi_it->scan_dir = 1; /* FIXME: do we need to have control on this? */ | |
847 | bidi_it->resolved_level = bidi_it->level_stack[0].level; | |
848 | bidi_it->level_stack[0].override = NEUTRAL_DIR; /* X1 */ | |
849 | bidi_it->invalid_levels = 0; | |
850 | bidi_it->invalid_rl_levels = -1; | |
4787455f EZ |
851 | /* Setting this to zero will force its recomputation the first time |
852 | we need it for W5. */ | |
853 | bidi_it->next_en_pos = 0; | |
7b5d6677 | 854 | bidi_it->next_en_type = UNKNOWN_BT; |
be39f003 | 855 | bidi_it->next_for_ws.type = UNKNOWN_BT; |
b44d9321 | 856 | bidi_set_sor_type (bidi_it, |
512a289d | 857 | (bidi_it->paragraph_dir == R2L ? 1 : 0), |
be39f003 EZ |
858 | bidi_it->level_stack[0].level); /* X10 */ |
859 | ||
860 | bidi_cache_reset (); | |
861 | } | |
862 | ||
cbb09f04 EZ |
863 | \f |
864 | /*********************************************************************** | |
865 | Fetching characters | |
866 | ***********************************************************************/ | |
867 | ||
f3014ef5 EZ |
868 | /* Count bytes in string S between BEG/BEGBYTE and END. BEG and END |
869 | are zero-based character positions in S, BEGBYTE is byte position | |
2cc21167 | 870 | corresponding to BEG. UNIBYTE means S is a unibyte string. */ |
0a99eee1 | 871 | static ptrdiff_t |
d311d28c | 872 | bidi_count_bytes (const unsigned char *s, const ptrdiff_t beg, |
2cc21167 | 873 | const ptrdiff_t begbyte, const ptrdiff_t end, bool unibyte) |
87e67904 | 874 | { |
d311d28c | 875 | ptrdiff_t pos = beg; |
87e67904 EZ |
876 | const unsigned char *p = s + begbyte, *start = p; |
877 | ||
f3014ef5 EZ |
878 | if (unibyte) |
879 | p = s + end; | |
880 | else | |
87e67904 | 881 | { |
f3014ef5 | 882 | if (!CHAR_HEAD_P (*p)) |
1088b922 | 883 | emacs_abort (); |
f3014ef5 EZ |
884 | |
885 | while (pos < end) | |
886 | { | |
887 | p += BYTES_BY_CHAR_HEAD (*p); | |
888 | pos++; | |
889 | } | |
87e67904 EZ |
890 | } |
891 | ||
892 | return p - start; | |
893 | } | |
894 | ||
05584c31 | 895 | /* Fetch and return the character at byte position BYTEPOS. If S is |
87e67904 | 896 | non-NULL, fetch the character from string S; otherwise fetch the |
2cc21167 | 897 | character from the current buffer. UNIBYTE means S is a |
f3014ef5 | 898 | unibyte string. */ |
0a99eee1 | 899 | static int |
2cc21167 | 900 | bidi_char_at_pos (ptrdiff_t bytepos, const unsigned char *s, bool unibyte) |
87e67904 EZ |
901 | { |
902 | if (s) | |
f3014ef5 | 903 | { |
05584c31 | 904 | s += bytepos; |
f3014ef5 | 905 | if (unibyte) |
05584c31 | 906 | return *s; |
f3014ef5 | 907 | } |
87e67904 | 908 | else |
05584c31 PE |
909 | s = BYTE_POS_ADDR (bytepos); |
910 | return STRING_CHAR (s); | |
87e67904 EZ |
911 | } |
912 | ||
36075a19 | 913 | /* Fetch and return the character at CHARPOS/BYTEPOS. If that |
102ebb00 | 914 | character is covered by a display string, treat the entire run of |
0c95fcf7 EZ |
915 | covered characters as a single character, either u+2029 or u+FFFC, |
916 | and return their combined length in CH_LEN and NCHARS. DISP_POS | |
917 | specifies the character position of the next display string, or -1 | |
b75258b3 EZ |
918 | if not yet computed. When the next character is at or beyond that |
919 | position, the function updates DISP_POS with the position of the | |
2cc21167 | 920 | next display string. *DISP_PROP non-zero means that there's really |
0c95fcf7 | 921 | a display string at DISP_POS, as opposed to when we searched till |
2cc21167 | 922 | DISP_POS without finding one. If *DISP_PROP is 2, it means the |
0c95fcf7 | 923 | display spec is of the form `(space ...)', which is replaced with |
b75258b3 EZ |
924 | u+2029 to handle it as a paragraph separator. STRING->s is the C |
925 | string to iterate, or NULL if iterating over a buffer or a Lisp | |
926 | string; in the latter case, STRING->lstring is the Lisp string. */ | |
0a99eee1 | 927 | static int |
36075a19 | 928 | bidi_fetch_char (ptrdiff_t charpos, ptrdiff_t bytepos, ptrdiff_t *disp_pos, |
0c95fcf7 | 929 | int *disp_prop, struct bidi_string_data *string, |
5bf97bfc | 930 | struct window *w, |
2cc21167 | 931 | bool frame_window_p, ptrdiff_t *ch_len, ptrdiff_t *nchars) |
182ce2d2 EZ |
932 | { |
933 | int ch; | |
5895d7b9 | 934 | ptrdiff_t endpos |
512a289d | 935 | = (string->s || STRINGP (string->lstring)) ? string->schars : ZV; |
6db161be | 936 | struct text_pos pos; |
e99a9b8b | 937 | int len; |
182ce2d2 | 938 | |
182ce2d2 | 939 | /* If we got past the last known position of display string, compute |
87e67904 EZ |
940 | the position of the next one. That position could be at CHARPOS. */ |
941 | if (charpos < endpos && charpos > *disp_pos) | |
6db161be EZ |
942 | { |
943 | SET_TEXT_POS (pos, charpos, bytepos); | |
5bf97bfc | 944 | *disp_pos = compute_display_string_pos (&pos, string, w, frame_window_p, |
0c95fcf7 | 945 | disp_prop); |
6db161be | 946 | } |
102ebb00 EZ |
947 | |
948 | /* Fetch the character at BYTEPOS. */ | |
87e67904 | 949 | if (charpos >= endpos) |
182ce2d2 EZ |
950 | { |
951 | ch = BIDI_EOB; | |
952 | *ch_len = 1; | |
953 | *nchars = 1; | |
87e67904 | 954 | *disp_pos = endpos; |
0c95fcf7 | 955 | *disp_prop = 0; |
182ce2d2 | 956 | } |
0c95fcf7 | 957 | else if (charpos >= *disp_pos && *disp_prop) |
182ce2d2 | 958 | { |
d311d28c | 959 | ptrdiff_t disp_end_pos; |
7b600102 EZ |
960 | |
961 | /* We don't expect to find ourselves in the middle of a display | |
962 | property. Hopefully, it will never be needed. */ | |
963 | if (charpos > *disp_pos) | |
1088b922 | 964 | emacs_abort (); |
0c95fcf7 EZ |
965 | /* Text covered by `display' properties and overlays with |
966 | display properties or display strings is handled as a single | |
967 | character that represents the entire run of characters | |
968 | covered by the display property. */ | |
969 | if (*disp_prop == 2) | |
970 | { | |
971 | /* `(space ...)' display specs are handled as paragraph | |
972 | separators for the purposes of the reordering; see UAX#9 | |
973 | section 3 and clause HL1 in section 4.3 there. */ | |
974 | ch = 0x2029; | |
975 | } | |
976 | else | |
977 | { | |
978 | /* All other display specs are handled as the Unicode Object | |
979 | Replacement Character. */ | |
980 | ch = 0xFFFC; | |
981 | } | |
87e67904 | 982 | disp_end_pos = compute_display_string_end (*disp_pos, string); |
fbcaa2f3 EZ |
983 | if (disp_end_pos < 0) |
984 | { | |
985 | /* Somebody removed the display string from the buffer | |
986 | behind our back. Recover by processing this buffer | |
987 | position as if no display property were present there to | |
988 | begin with. */ | |
989 | *disp_prop = 0; | |
990 | goto normal_char; | |
991 | } | |
7b600102 | 992 | *nchars = disp_end_pos - *disp_pos; |
f3014ef5 | 993 | if (*nchars <= 0) |
1088b922 | 994 | emacs_abort (); |
87e67904 EZ |
995 | if (string->s) |
996 | *ch_len = bidi_count_bytes (string->s, *disp_pos, bytepos, | |
f3014ef5 | 997 | disp_end_pos, string->unibyte); |
9f257352 EZ |
998 | else if (STRINGP (string->lstring)) |
999 | *ch_len = bidi_count_bytes (SDATA (string->lstring), *disp_pos, | |
f3014ef5 | 1000 | bytepos, disp_end_pos, string->unibyte); |
87e67904 EZ |
1001 | else |
1002 | *ch_len = CHAR_TO_BYTE (disp_end_pos) - bytepos; | |
182ce2d2 | 1003 | } |
182ce2d2 EZ |
1004 | else |
1005 | { | |
fbcaa2f3 | 1006 | normal_char: |
87e67904 EZ |
1007 | if (string->s) |
1008 | { | |
87e67904 | 1009 | |
f3014ef5 EZ |
1010 | if (!string->unibyte) |
1011 | { | |
1012 | ch = STRING_CHAR_AND_LENGTH (string->s + bytepos, len); | |
1013 | *ch_len = len; | |
1014 | } | |
1015 | else | |
1016 | { | |
1017 | ch = UNIBYTE_TO_CHAR (string->s[bytepos]); | |
1018 | *ch_len = 1; | |
1019 | } | |
87e67904 | 1020 | } |
9f257352 EZ |
1021 | else if (STRINGP (string->lstring)) |
1022 | { | |
f3014ef5 EZ |
1023 | if (!string->unibyte) |
1024 | { | |
1025 | ch = STRING_CHAR_AND_LENGTH (SDATA (string->lstring) + bytepos, | |
1026 | len); | |
1027 | *ch_len = len; | |
1028 | } | |
1029 | else | |
1030 | { | |
1031 | ch = UNIBYTE_TO_CHAR (SREF (string->lstring, bytepos)); | |
1032 | *ch_len = 1; | |
1033 | } | |
9f257352 | 1034 | } |
87e67904 EZ |
1035 | else |
1036 | { | |
e99a9b8b EZ |
1037 | ch = STRING_CHAR_AND_LENGTH (BYTE_POS_ADDR (bytepos), len); |
1038 | *ch_len = len; | |
87e67904 | 1039 | } |
182ce2d2 EZ |
1040 | *nchars = 1; |
1041 | } | |
1042 | ||
1043 | /* If we just entered a run of characters covered by a display | |
1044 | string, compute the position of the next display string. */ | |
55439c61 | 1045 | if (charpos + *nchars <= endpos && charpos + *nchars > *disp_pos |
0c95fcf7 | 1046 | && *disp_prop) |
6db161be EZ |
1047 | { |
1048 | SET_TEXT_POS (pos, charpos + *nchars, bytepos + *ch_len); | |
5bf97bfc | 1049 | *disp_pos = compute_display_string_pos (&pos, string, w, frame_window_p, |
0c95fcf7 | 1050 | disp_prop); |
6db161be | 1051 | } |
182ce2d2 EZ |
1052 | |
1053 | return ch; | |
1054 | } | |
1055 | ||
cbb09f04 EZ |
1056 | \f |
1057 | /*********************************************************************** | |
1058 | Determining paragraph direction | |
1059 | ***********************************************************************/ | |
1060 | ||
1061 | /* Check if buffer position CHARPOS/BYTEPOS is the end of a paragraph. | |
1062 | Value is the non-negative length of the paragraph separator | |
1063 | following the buffer position, -1 if position is at the beginning | |
1064 | of a new paragraph, or -2 if position is neither at beginning nor | |
1065 | at end of a paragraph. */ | |
d311d28c PE |
1066 | static ptrdiff_t |
1067 | bidi_at_paragraph_end (ptrdiff_t charpos, ptrdiff_t bytepos) | |
cbb09f04 EZ |
1068 | { |
1069 | Lisp_Object sep_re; | |
1070 | Lisp_Object start_re; | |
d311d28c | 1071 | ptrdiff_t val; |
cbb09f04 EZ |
1072 | |
1073 | sep_re = paragraph_separate_re; | |
1074 | start_re = paragraph_start_re; | |
1075 | ||
1076 | val = fast_looking_at (sep_re, charpos, bytepos, ZV, ZV_BYTE, Qnil); | |
1077 | if (val < 0) | |
1078 | { | |
1079 | if (fast_looking_at (start_re, charpos, bytepos, ZV, ZV_BYTE, Qnil) >= 0) | |
1080 | val = -1; | |
1081 | else | |
1082 | val = -2; | |
1083 | } | |
1084 | ||
1085 | return val; | |
1086 | } | |
1087 | ||
1137e8b8 EZ |
1088 | /* On my 2005-vintage machine, searching back for paragraph start |
1089 | takes ~1 ms per line. And bidi_paragraph_init is called 4 times | |
1090 | when user types C-p. The number below limits each call to | |
1091 | bidi_paragraph_init to about 10 ms. */ | |
1092 | #define MAX_PARAGRAPH_SEARCH 7500 | |
1093 | ||
be39f003 | 1094 | /* Find the beginning of this paragraph by looking back in the buffer. |
1137e8b8 EZ |
1095 | Value is the byte position of the paragraph's beginning, or |
1096 | BEGV_BYTE if paragraph_start_re is still not found after looking | |
1097 | back MAX_PARAGRAPH_SEARCH lines in the buffer. */ | |
d311d28c PE |
1098 | static ptrdiff_t |
1099 | bidi_find_paragraph_start (ptrdiff_t pos, ptrdiff_t pos_byte) | |
6bff6497 | 1100 | { |
372b7a95 | 1101 | Lisp_Object re = paragraph_start_re; |
d311d28c | 1102 | ptrdiff_t limit = ZV, limit_byte = ZV_BYTE; |
4c0078d4 | 1103 | ptrdiff_t n = 0; |
6bff6497 | 1104 | |
6bff6497 | 1105 | while (pos_byte > BEGV_BYTE |
1137e8b8 | 1106 | && n++ < MAX_PARAGRAPH_SEARCH |
6bff6497 | 1107 | && fast_looking_at (re, pos, pos_byte, limit, limit_byte, Qnil) < 0) |
b5426561 DA |
1108 | { |
1109 | /* FIXME: What if the paragraph beginning is covered by a | |
1110 | display string? And what if a display string covering some | |
1111 | of the text over which we scan back includes | |
1112 | paragraph_start_re? */ | |
1113 | DEC_BOTH (pos, pos_byte); | |
1114 | pos = find_newline_no_quit (pos, pos_byte, -1, &pos_byte); | |
1115 | } | |
1137e8b8 EZ |
1116 | if (n >= MAX_PARAGRAPH_SEARCH) |
1117 | pos_byte = BEGV_BYTE; | |
be39f003 | 1118 | return pos_byte; |
6bff6497 EZ |
1119 | } |
1120 | ||
ce811ad9 EZ |
1121 | /* On a 3.4 GHz machine, searching forward for a strong directional |
1122 | character in a long paragraph full of weaks or neutrals takes about | |
1123 | 1 ms for each 20K characters. The number below limits each call to | |
1124 | bidi_paragraph_init to less than 10 ms even on slow machines. */ | |
1125 | #define MAX_STRONG_CHAR_SEARCH 100000 | |
1126 | ||
bea4f10c | 1127 | /* Determine the base direction, a.k.a. base embedding level, of the |
b44d9321 EZ |
1128 | paragraph we are about to iterate through. If DIR is either L2R or |
1129 | R2L, just use that. Otherwise, determine the paragraph direction | |
bea4f10c EZ |
1130 | from the first strong directional character of the paragraph. |
1131 | ||
2cc21167 | 1132 | NO_DEFAULT_P means don't default to L2R if the paragraph |
bea4f10c EZ |
1133 | has no strong directional characters and both DIR and |
1134 | bidi_it->paragraph_dir are NEUTRAL_DIR. In that case, search back | |
1135 | in the buffer until a paragraph is found with a strong character, | |
1136 | or until hitting BEGV. In the latter case, fall back to L2R. This | |
1137 | flag is used in current-bidi-paragraph-direction. | |
1138 | ||
1139 | Note that this function gives the paragraph separator the same | |
1140 | direction as the preceding paragraph, even though Emacs generally | |
9858f6c3 | 1141 | views the separator as not belonging to any paragraph. */ |
b7b65b15 | 1142 | void |
2cc21167 | 1143 | bidi_paragraph_init (bidi_dir_t dir, struct bidi_it *bidi_it, bool no_default_p) |
b7b65b15 | 1144 | { |
d311d28c | 1145 | ptrdiff_t bytepos = bidi_it->bytepos; |
2cc21167 | 1146 | bool string_p = bidi_it->string.s || STRINGP (bidi_it->string.lstring); |
d311d28c | 1147 | ptrdiff_t pstartbyte; |
87e67904 EZ |
1148 | /* Note that begbyte is a byte position, while end is a character |
1149 | position. Yes, this is ugly, but we are trying to avoid costly | |
1150 | calls to BYTE_TO_CHAR and its ilk. */ | |
d311d28c PE |
1151 | ptrdiff_t begbyte = string_p ? 0 : BEGV_BYTE; |
1152 | ptrdiff_t end = string_p ? bidi_it->string.schars : ZV; | |
e7402cb2 | 1153 | |
5e65aec0 | 1154 | /* Special case for an empty buffer. */ |
87e67904 | 1155 | if (bytepos == begbyte && bidi_it->charpos == end) |
5e65aec0 | 1156 | dir = L2R; |
9c82e145 | 1157 | /* We should never be called at EOB or before BEGV. */ |
87e67904 | 1158 | else if (bidi_it->charpos >= end || bytepos < begbyte) |
1088b922 | 1159 | emacs_abort (); |
9c82e145 | 1160 | |
be39f003 EZ |
1161 | if (dir == L2R) |
1162 | { | |
1163 | bidi_it->paragraph_dir = L2R; | |
1164 | bidi_it->new_paragraph = 0; | |
1165 | } | |
1166 | else if (dir == R2L) | |
1167 | { | |
1168 | bidi_it->paragraph_dir = R2L; | |
1169 | bidi_it->new_paragraph = 0; | |
1170 | } | |
b7b65b15 EZ |
1171 | else if (dir == NEUTRAL_DIR) /* P2 */ |
1172 | { | |
182ce2d2 | 1173 | int ch; |
d311d28c PE |
1174 | ptrdiff_t ch_len, nchars; |
1175 | ptrdiff_t pos, disp_pos = -1; | |
0c95fcf7 | 1176 | int disp_prop = 0; |
6bff6497 | 1177 | bidi_type_t type; |
9f257352 | 1178 | const unsigned char *s; |
be39f003 | 1179 | |
d20e1419 EZ |
1180 | if (!bidi_initialized) |
1181 | bidi_initialize (); | |
1182 | ||
be39f003 EZ |
1183 | /* If we are inside a paragraph separator, we are just waiting |
1184 | for the separator to be exhausted; use the previous paragraph | |
e5a2fec7 EZ |
1185 | direction. But don't do that if we have been just reseated, |
1186 | because we need to reinitialize below in that case. */ | |
1187 | if (!bidi_it->first_elt | |
1188 | && bidi_it->charpos < bidi_it->separator_limit) | |
be39f003 EZ |
1189 | return; |
1190 | ||
b44d9321 | 1191 | /* If we are on a newline, get past it to where the next |
5e65aec0 EZ |
1192 | paragraph might start. But don't do that at BEGV since then |
1193 | we are potentially in a new paragraph that doesn't yet | |
1194 | exist. */ | |
c143c213 | 1195 | pos = bidi_it->charpos; |
512a289d RS |
1196 | s = (STRINGP (bidi_it->string.lstring) |
1197 | ? SDATA (bidi_it->string.lstring) | |
1198 | : bidi_it->string.s); | |
f3014ef5 EZ |
1199 | if (bytepos > begbyte |
1200 | && bidi_char_at_pos (bytepos, s, bidi_it->string.unibyte) == '\n') | |
be39f003 | 1201 | { |
b44d9321 | 1202 | bytepos++; |
c143c213 | 1203 | pos++; |
be39f003 | 1204 | } |
b44d9321 EZ |
1205 | |
1206 | /* We are either at the beginning of a paragraph or in the | |
1207 | middle of it. Find where this paragraph starts. */ | |
87e67904 EZ |
1208 | if (string_p) |
1209 | { | |
1210 | /* We don't support changes of paragraph direction inside a | |
1211 | string. It is treated as a single paragraph. */ | |
1212 | pstartbyte = 0; | |
1213 | } | |
1214 | else | |
1215 | pstartbyte = bidi_find_paragraph_start (pos, bytepos); | |
be39f003 EZ |
1216 | bidi_it->separator_limit = -1; |
1217 | bidi_it->new_paragraph = 0; | |
bea4f10c | 1218 | |
2cc21167 PE |
1219 | /* The following loop is run more than once only if NO_DEFAULT_P, |
1220 | and only if we are iterating on a buffer. */ | |
bea4f10c | 1221 | do { |
ce811ad9 EZ |
1222 | ptrdiff_t pos1; |
1223 | ||
bea4f10c | 1224 | bytepos = pstartbyte; |
87e67904 EZ |
1225 | if (!string_p) |
1226 | pos = BYTE_TO_CHAR (bytepos); | |
36075a19 | 1227 | ch = bidi_fetch_char (pos, bytepos, &disp_pos, &disp_prop, |
5bf97bfc | 1228 | &bidi_it->string, bidi_it->w, |
87e67904 | 1229 | bidi_it->frame_window_p, &ch_len, &nchars); |
bea4f10c EZ |
1230 | type = bidi_get_type (ch, NEUTRAL_DIR); |
1231 | ||
ce811ad9 | 1232 | pos1 = pos; |
182ce2d2 | 1233 | for (pos += nchars, bytepos += ch_len; |
ce811ad9 EZ |
1234 | ((bidi_get_category (type) != STRONG) |
1235 | || (bidi_ignore_explicit_marks_for_paragraph_level | |
1236 | && (type == RLE || type == RLO | |
1237 | || type == LRE || type == LRO))) | |
1238 | /* Stop when searched too far into an abnormally large | |
1239 | paragraph full of weak or neutral characters. */ | |
1240 | && pos - pos1 < MAX_STRONG_CHAR_SEARCH; | |
bea4f10c EZ |
1241 | type = bidi_get_type (ch, NEUTRAL_DIR)) |
1242 | { | |
87e67904 | 1243 | if (pos >= end) |
bea4f10c EZ |
1244 | { |
1245 | /* Pretend there's a paragraph separator at end of | |
87e67904 | 1246 | buffer/string. */ |
bea4f10c EZ |
1247 | type = NEUTRAL_B; |
1248 | break; | |
1249 | } | |
0bb23927 EZ |
1250 | if (!string_p |
1251 | && type == NEUTRAL_B | |
1252 | && bidi_at_paragraph_end (pos, bytepos) >= -1) | |
cf99dcf8 | 1253 | break; |
102ebb00 | 1254 | /* Fetch next character and advance to get past it. */ |
36075a19 | 1255 | ch = bidi_fetch_char (pos, bytepos, &disp_pos, |
5bf97bfc | 1256 | &disp_prop, &bidi_it->string, bidi_it->w, |
fc6f18ce | 1257 | bidi_it->frame_window_p, &ch_len, &nchars); |
182ce2d2 EZ |
1258 | pos += nchars; |
1259 | bytepos += ch_len; | |
bea4f10c | 1260 | } |
32413314 EZ |
1261 | if ((type == STRONG_R || type == STRONG_AL) /* P3 */ |
1262 | || (!bidi_ignore_explicit_marks_for_paragraph_level | |
1263 | && (type == RLO || type == RLE))) | |
bea4f10c | 1264 | bidi_it->paragraph_dir = R2L; |
32413314 EZ |
1265 | else if (type == STRONG_L |
1266 | || (!bidi_ignore_explicit_marks_for_paragraph_level | |
1267 | && (type == LRO || type == LRE))) | |
bea4f10c | 1268 | bidi_it->paragraph_dir = L2R; |
87e67904 EZ |
1269 | if (!string_p |
1270 | && no_default_p && bidi_it->paragraph_dir == NEUTRAL_DIR) | |
bea4f10c EZ |
1271 | { |
1272 | /* If this paragraph is at BEGV, default to L2R. */ | |
1273 | if (pstartbyte == BEGV_BYTE) | |
1274 | bidi_it->paragraph_dir = L2R; /* P3 and HL1 */ | |
1275 | else | |
1276 | { | |
d311d28c PE |
1277 | ptrdiff_t prevpbyte = pstartbyte; |
1278 | ptrdiff_t p = BYTE_TO_CHAR (pstartbyte), pbyte = pstartbyte; | |
bea4f10c EZ |
1279 | |
1280 | /* Find the beginning of the previous paragraph, if any. */ | |
1281 | while (pbyte > BEGV_BYTE && prevpbyte >= pstartbyte) | |
1282 | { | |
182ce2d2 EZ |
1283 | /* FXIME: What if p is covered by a display |
1284 | string? See also a FIXME inside | |
1285 | bidi_find_paragraph_start. */ | |
36075a19 | 1286 | DEC_BOTH (p, pbyte); |
bea4f10c EZ |
1287 | prevpbyte = bidi_find_paragraph_start (p, pbyte); |
1288 | } | |
1289 | pstartbyte = prevpbyte; | |
1290 | } | |
1291 | } | |
87e67904 EZ |
1292 | } while (!string_p |
1293 | && no_default_p && bidi_it->paragraph_dir == NEUTRAL_DIR); | |
b7b65b15 | 1294 | } |
be39f003 | 1295 | else |
1088b922 | 1296 | emacs_abort (); |
b7b65b15 | 1297 | |
b44d9321 EZ |
1298 | /* Contrary to UAX#9 clause P3, we only default the paragraph |
1299 | direction to L2R if we have no previous usable paragraph | |
bea4f10c | 1300 | direction. This is allowed by the HL1 clause. */ |
d20e1419 | 1301 | if (bidi_it->paragraph_dir != L2R && bidi_it->paragraph_dir != R2L) |
bea4f10c | 1302 | bidi_it->paragraph_dir = L2R; /* P3 and HL1 ``higher-level protocols'' */ |
be39f003 | 1303 | if (bidi_it->paragraph_dir == R2L) |
b44d9321 | 1304 | bidi_it->level_stack[0].level = 1; |
be39f003 | 1305 | else |
b44d9321 | 1306 | bidi_it->level_stack[0].level = 0; |
be39f003 EZ |
1307 | |
1308 | bidi_line_init (bidi_it); | |
b7b65b15 EZ |
1309 | } |
1310 | ||
cbb09f04 EZ |
1311 | \f |
1312 | /*********************************************************************** | |
1313 | Resolving explicit and implicit levels. | |
58b9f433 | 1314 | The rest of this file constitutes the core of the UBA implementation. |
cbb09f04 | 1315 | ***********************************************************************/ |
b7b65b15 | 1316 | |
0a99eee1 | 1317 | static bool |
182ce2d2 | 1318 | bidi_explicit_dir_char (int ch) |
b7b65b15 | 1319 | { |
182ce2d2 EZ |
1320 | bidi_type_t ch_type; |
1321 | ||
1322 | if (!bidi_initialized) | |
1088b922 | 1323 | emacs_abort (); |
182ce2d2 EZ |
1324 | ch_type = (bidi_type_t) XINT (CHAR_TABLE_REF (bidi_type_table, ch)); |
1325 | return (ch_type == LRE || ch_type == LRO | |
1326 | || ch_type == RLE || ch_type == RLO | |
1327 | || ch_type == PDF); | |
b7b65b15 EZ |
1328 | } |
1329 | ||
1330 | /* A helper function for bidi_resolve_explicit. It advances to the | |
1331 | next character in logical order and determines the new embedding | |
1332 | level and directional override, but does not take into account | |
1333 | empty embeddings. */ | |
1334 | static int | |
1335 | bidi_resolve_explicit_1 (struct bidi_it *bidi_it) | |
1336 | { | |
1337 | int curchar; | |
1338 | bidi_type_t type; | |
1339 | int current_level; | |
1340 | int new_level; | |
1341 | bidi_dir_t override; | |
2cc21167 | 1342 | bool string_p = bidi_it->string.s || STRINGP (bidi_it->string.lstring); |
b7b65b15 | 1343 | |
182ce2d2 EZ |
1344 | /* If reseat()'ed, don't advance, so as to start iteration from the |
1345 | position where we were reseated. bidi_it->bytepos can be less | |
1346 | than BEGV_BYTE after reseat to BEGV. */ | |
87e67904 | 1347 | if (bidi_it->bytepos < (string_p ? 0 : BEGV_BYTE) |
9c82e145 | 1348 | || bidi_it->first_elt) |
e7402cb2 | 1349 | { |
9c82e145 | 1350 | bidi_it->first_elt = 0; |
87e67904 EZ |
1351 | if (string_p) |
1352 | { | |
512a289d RS |
1353 | const unsigned char *p |
1354 | = (STRINGP (bidi_it->string.lstring) | |
1355 | ? SDATA (bidi_it->string.lstring) | |
1356 | : bidi_it->string.s); | |
9f257352 | 1357 | |
87e67904 | 1358 | if (bidi_it->charpos < 0) |
05e193f1 EZ |
1359 | bidi_it->charpos = bidi_it->bytepos = 0; |
1360 | eassert (bidi_it->bytepos == bidi_count_bytes (p, 0, 0, | |
1361 | bidi_it->charpos, | |
1362 | bidi_it->string.unibyte)); | |
87e67904 EZ |
1363 | } |
1364 | else | |
1365 | { | |
1366 | if (bidi_it->charpos < BEGV) | |
05e193f1 EZ |
1367 | { |
1368 | bidi_it->charpos = BEGV; | |
1369 | bidi_it->bytepos = BEGV_BYTE; | |
1370 | } | |
1371 | eassert (bidi_it->bytepos == CHAR_TO_BYTE (bidi_it->charpos)); | |
87e67904 | 1372 | } |
e7402cb2 | 1373 | } |
87e67904 EZ |
1374 | /* Don't move at end of buffer/string. */ |
1375 | else if (bidi_it->charpos < (string_p ? bidi_it->string.schars : ZV)) | |
b7b65b15 | 1376 | { |
182ce2d2 EZ |
1377 | /* Advance to the next character, skipping characters covered by |
1378 | display strings (nchars > 1). */ | |
102ebb00 | 1379 | if (bidi_it->nchars <= 0) |
1088b922 | 1380 | emacs_abort (); |
182ce2d2 | 1381 | bidi_it->charpos += bidi_it->nchars; |
e7402cb2 | 1382 | if (bidi_it->ch_len == 0) |
1088b922 | 1383 | emacs_abort (); |
b7b65b15 EZ |
1384 | bidi_it->bytepos += bidi_it->ch_len; |
1385 | } | |
1386 | ||
1387 | current_level = bidi_it->level_stack[bidi_it->stack_idx].level; /* X1 */ | |
1388 | override = bidi_it->level_stack[bidi_it->stack_idx].override; | |
1389 | new_level = current_level; | |
1390 | ||
87e67904 | 1391 | if (bidi_it->charpos >= (string_p ? bidi_it->string.schars : ZV)) |
e7402cb2 EZ |
1392 | { |
1393 | curchar = BIDI_EOB; | |
1394 | bidi_it->ch_len = 1; | |
182ce2d2 | 1395 | bidi_it->nchars = 1; |
87e67904 | 1396 | bidi_it->disp_pos = (string_p ? bidi_it->string.schars : ZV); |
0c95fcf7 | 1397 | bidi_it->disp_prop = 0; |
e7402cb2 EZ |
1398 | } |
1399 | else | |
1400 | { | |
182ce2d2 EZ |
1401 | /* Fetch the character at BYTEPOS. If it is covered by a |
1402 | display string, treat the entire run of covered characters as | |
1403 | a single character u+FFFC. */ | |
36075a19 | 1404 | curchar = bidi_fetch_char (bidi_it->charpos, bidi_it->bytepos, |
0c95fcf7 | 1405 | &bidi_it->disp_pos, &bidi_it->disp_prop, |
5bf97bfc EZ |
1406 | &bidi_it->string, bidi_it->w, |
1407 | bidi_it->frame_window_p, | |
102ebb00 | 1408 | &bidi_it->ch_len, &bidi_it->nchars); |
e7402cb2 | 1409 | } |
b7b65b15 | 1410 | bidi_it->ch = curchar; |
b7b65b15 | 1411 | |
6bff6497 EZ |
1412 | /* Don't apply directional override here, as all the types we handle |
1413 | below will not be affected by the override anyway, and we need | |
1414 | the original type unaltered. The override will be applied in | |
1415 | bidi_resolve_weak. */ | |
1416 | type = bidi_get_type (curchar, NEUTRAL_DIR); | |
89d3374a EZ |
1417 | bidi_it->orig_type = type; |
1418 | bidi_check_type (bidi_it->orig_type); | |
b7b65b15 EZ |
1419 | |
1420 | if (type != PDF) | |
1421 | bidi_it->prev_was_pdf = 0; | |
1422 | ||
89d3374a | 1423 | bidi_it->type_after_w1 = UNKNOWN_BT; |
b7b65b15 EZ |
1424 | |
1425 | switch (type) | |
1426 | { | |
1427 | case RLE: /* X2 */ | |
1428 | case RLO: /* X4 */ | |
89d3374a EZ |
1429 | bidi_it->type_after_w1 = type; |
1430 | bidi_check_type (bidi_it->type_after_w1); | |
b7b65b15 | 1431 | type = WEAK_BN; /* X9/Retaining */ |
87e67904 | 1432 | if (bidi_it->ignore_bn_limit <= -1) |
b7b65b15 EZ |
1433 | { |
1434 | if (current_level <= BIDI_MAXLEVEL - 4) | |
1435 | { | |
1436 | /* Compute the least odd embedding level greater than | |
1437 | the current level. */ | |
1438 | new_level = ((current_level + 1) & ~1) + 1; | |
89d3374a | 1439 | if (bidi_it->type_after_w1 == RLE) |
b7b65b15 EZ |
1440 | override = NEUTRAL_DIR; |
1441 | else | |
1442 | override = R2L; | |
1443 | if (current_level == BIDI_MAXLEVEL - 4) | |
1444 | bidi_it->invalid_rl_levels = 0; | |
1445 | bidi_push_embedding_level (bidi_it, new_level, override); | |
1446 | } | |
1447 | else | |
1448 | { | |
1449 | bidi_it->invalid_levels++; | |
1450 | /* See the commentary about invalid_rl_levels below. */ | |
1451 | if (bidi_it->invalid_rl_levels < 0) | |
1452 | bidi_it->invalid_rl_levels = 0; | |
1453 | bidi_it->invalid_rl_levels++; | |
1454 | } | |
1455 | } | |
89d3374a | 1456 | else if (bidi_it->prev.type_after_w1 == WEAK_EN /* W5/Retaining */ |
7b5d6677 EZ |
1457 | || (bidi_it->next_en_pos > bidi_it->charpos |
1458 | && bidi_it->next_en_type == WEAK_EN)) | |
b7b65b15 EZ |
1459 | type = WEAK_EN; |
1460 | break; | |
1461 | case LRE: /* X3 */ | |
1462 | case LRO: /* X5 */ | |
89d3374a EZ |
1463 | bidi_it->type_after_w1 = type; |
1464 | bidi_check_type (bidi_it->type_after_w1); | |
b7b65b15 | 1465 | type = WEAK_BN; /* X9/Retaining */ |
87e67904 | 1466 | if (bidi_it->ignore_bn_limit <= -1) |
b7b65b15 EZ |
1467 | { |
1468 | if (current_level <= BIDI_MAXLEVEL - 5) | |
1469 | { | |
1470 | /* Compute the least even embedding level greater than | |
1471 | the current level. */ | |
1472 | new_level = ((current_level + 2) & ~1); | |
89d3374a | 1473 | if (bidi_it->type_after_w1 == LRE) |
b7b65b15 EZ |
1474 | override = NEUTRAL_DIR; |
1475 | else | |
1476 | override = L2R; | |
1477 | bidi_push_embedding_level (bidi_it, new_level, override); | |
1478 | } | |
1479 | else | |
1480 | { | |
1481 | bidi_it->invalid_levels++; | |
1482 | /* invalid_rl_levels counts invalid levels encountered | |
1483 | while the embedding level was already too high for | |
1484 | LRE/LRO, but not for RLE/RLO. That is because | |
1485 | there may be exactly one PDF which we should not | |
1486 | ignore even though invalid_levels is non-zero. | |
1487 | invalid_rl_levels helps to know what PDF is | |
1488 | that. */ | |
1489 | if (bidi_it->invalid_rl_levels >= 0) | |
1490 | bidi_it->invalid_rl_levels++; | |
1491 | } | |
1492 | } | |
89d3374a | 1493 | else if (bidi_it->prev.type_after_w1 == WEAK_EN /* W5/Retaining */ |
7b5d6677 EZ |
1494 | || (bidi_it->next_en_pos > bidi_it->charpos |
1495 | && bidi_it->next_en_type == WEAK_EN)) | |
b7b65b15 EZ |
1496 | type = WEAK_EN; |
1497 | break; | |
1498 | case PDF: /* X7 */ | |
89d3374a EZ |
1499 | bidi_it->type_after_w1 = type; |
1500 | bidi_check_type (bidi_it->type_after_w1); | |
b7b65b15 | 1501 | type = WEAK_BN; /* X9/Retaining */ |
87e67904 | 1502 | if (bidi_it->ignore_bn_limit <= -1) |
b7b65b15 EZ |
1503 | { |
1504 | if (!bidi_it->invalid_rl_levels) | |
1505 | { | |
1506 | new_level = bidi_pop_embedding_level (bidi_it); | |
1507 | bidi_it->invalid_rl_levels = -1; | |
1508 | if (bidi_it->invalid_levels) | |
1509 | bidi_it->invalid_levels--; | |
1510 | /* else nothing: UAX#9 says to ignore invalid PDFs */ | |
1511 | } | |
1512 | if (!bidi_it->invalid_levels) | |
1513 | new_level = bidi_pop_embedding_level (bidi_it); | |
1514 | else | |
1515 | { | |
1516 | bidi_it->invalid_levels--; | |
1517 | bidi_it->invalid_rl_levels--; | |
1518 | } | |
1519 | } | |
89d3374a | 1520 | else if (bidi_it->prev.type_after_w1 == WEAK_EN /* W5/Retaining */ |
7b5d6677 EZ |
1521 | || (bidi_it->next_en_pos > bidi_it->charpos |
1522 | && bidi_it->next_en_type == WEAK_EN)) | |
b7b65b15 EZ |
1523 | type = WEAK_EN; |
1524 | break; | |
1525 | default: | |
1526 | /* Nothing. */ | |
1527 | break; | |
1528 | } | |
1529 | ||
1530 | bidi_it->type = type; | |
2d6e4628 | 1531 | bidi_check_type (bidi_it->type); |
b7b65b15 EZ |
1532 | |
1533 | return new_level; | |
1534 | } | |
1535 | ||
1536 | /* Given an iterator state in BIDI_IT, advance one character position | |
182ce2d2 EZ |
1537 | in the buffer/string to the next character (in the logical order), |
1538 | resolve any explicit embeddings and directional overrides, and | |
1539 | return the embedding level of the character after resolving | |
1540 | explicit directives and ignoring empty embeddings. */ | |
b7b65b15 EZ |
1541 | static int |
1542 | bidi_resolve_explicit (struct bidi_it *bidi_it) | |
1543 | { | |
1544 | int prev_level = bidi_it->level_stack[bidi_it->stack_idx].level; | |
1545 | int new_level = bidi_resolve_explicit_1 (bidi_it); | |
d311d28c | 1546 | ptrdiff_t eob = bidi_it->string.s ? bidi_it->string.schars : ZV; |
512a289d RS |
1547 | const unsigned char *s |
1548 | = (STRINGP (bidi_it->string.lstring) | |
1549 | ? SDATA (bidi_it->string.lstring) | |
1550 | : bidi_it->string.s); | |
b7b65b15 EZ |
1551 | |
1552 | if (prev_level < new_level | |
1553 | && bidi_it->type == WEAK_BN | |
87e67904 EZ |
1554 | && bidi_it->ignore_bn_limit == -1 /* only if not already known */ |
1555 | && bidi_it->charpos < eob /* not already at EOB */ | |
1556 | && bidi_explicit_dir_char (bidi_char_at_pos (bidi_it->bytepos | |
f3014ef5 EZ |
1557 | + bidi_it->ch_len, s, |
1558 | bidi_it->string.unibyte))) | |
b7b65b15 EZ |
1559 | { |
1560 | /* Avoid pushing and popping embedding levels if the level run | |
1561 | is empty, as this breaks level runs where it shouldn't. | |
1562 | UAX#9 removes all the explicit embedding and override codes, | |
1563 | so empty embeddings disappear without a trace. We need to | |
1564 | behave as if we did the same. */ | |
1565 | struct bidi_it saved_it; | |
1566 | int level = prev_level; | |
1567 | ||
1568 | bidi_copy_it (&saved_it, bidi_it); | |
1569 | ||
87e67904 | 1570 | while (bidi_explicit_dir_char (bidi_char_at_pos (bidi_it->bytepos |
f3014ef5 EZ |
1571 | + bidi_it->ch_len, s, |
1572 | bidi_it->string.unibyte))) | |
b7b65b15 | 1573 | { |
182ce2d2 EZ |
1574 | /* This advances to the next character, skipping any |
1575 | characters covered by display strings. */ | |
b7b65b15 | 1576 | level = bidi_resolve_explicit_1 (bidi_it); |
9f257352 EZ |
1577 | /* If string.lstring was relocated inside bidi_resolve_explicit_1, |
1578 | a pointer to its data is no longer valid. */ | |
1579 | if (STRINGP (bidi_it->string.lstring)) | |
1580 | s = SDATA (bidi_it->string.lstring); | |
b7b65b15 EZ |
1581 | } |
1582 | ||
102ebb00 | 1583 | if (bidi_it->nchars <= 0) |
1088b922 | 1584 | emacs_abort (); |
b7b65b15 | 1585 | if (level == prev_level) /* empty embedding */ |
182ce2d2 | 1586 | saved_it.ignore_bn_limit = bidi_it->charpos + bidi_it->nchars; |
b7b65b15 | 1587 | else /* this embedding is non-empty */ |
87e67904 | 1588 | saved_it.ignore_bn_limit = -2; |
b7b65b15 EZ |
1589 | |
1590 | bidi_copy_it (bidi_it, &saved_it); | |
87e67904 | 1591 | if (bidi_it->ignore_bn_limit > -1) |
b7b65b15 EZ |
1592 | { |
1593 | /* We pushed a level, but we shouldn't have. Undo that. */ | |
1594 | if (!bidi_it->invalid_rl_levels) | |
1595 | { | |
1596 | new_level = bidi_pop_embedding_level (bidi_it); | |
1597 | bidi_it->invalid_rl_levels = -1; | |
1598 | if (bidi_it->invalid_levels) | |
1599 | bidi_it->invalid_levels--; | |
1600 | } | |
1601 | if (!bidi_it->invalid_levels) | |
1602 | new_level = bidi_pop_embedding_level (bidi_it); | |
1603 | else | |
1604 | { | |
1605 | bidi_it->invalid_levels--; | |
1606 | bidi_it->invalid_rl_levels--; | |
1607 | } | |
1608 | } | |
1609 | } | |
1610 | ||
b7b65b15 EZ |
1611 | if (bidi_it->type == NEUTRAL_B) /* X8 */ |
1612 | { | |
21fce5ab | 1613 | bidi_set_paragraph_end (bidi_it); |
6bff6497 EZ |
1614 | /* This is needed by bidi_resolve_weak below, and in L1. */ |
1615 | bidi_it->type_after_w1 = bidi_it->type; | |
89d3374a | 1616 | bidi_check_type (bidi_it->type_after_w1); |
b7b65b15 EZ |
1617 | } |
1618 | ||
1619 | return new_level; | |
1620 | } | |
1621 | ||
182ce2d2 EZ |
1622 | /* Advance in the buffer/string, resolve weak types and return the |
1623 | type of the next character after weak type resolution. */ | |
fd3998ff | 1624 | static bidi_type_t |
b7b65b15 EZ |
1625 | bidi_resolve_weak (struct bidi_it *bidi_it) |
1626 | { | |
1627 | bidi_type_t type; | |
1628 | bidi_dir_t override; | |
1629 | int prev_level = bidi_it->level_stack[bidi_it->stack_idx].level; | |
1630 | int new_level = bidi_resolve_explicit (bidi_it); | |
1631 | int next_char; | |
1632 | bidi_type_t type_of_next; | |
1633 | struct bidi_it saved_it; | |
5895d7b9 | 1634 | ptrdiff_t eob |
512a289d RS |
1635 | = ((STRINGP (bidi_it->string.lstring) || bidi_it->string.s) |
1636 | ? bidi_it->string.schars : ZV); | |
b7b65b15 EZ |
1637 | |
1638 | type = bidi_it->type; | |
1639 | override = bidi_it->level_stack[bidi_it->stack_idx].override; | |
1640 | ||
1641 | if (type == UNKNOWN_BT | |
1642 | || type == LRE | |
1643 | || type == LRO | |
1644 | || type == RLE | |
1645 | || type == RLO | |
1646 | || type == PDF) | |
1088b922 | 1647 | emacs_abort (); |
b7b65b15 EZ |
1648 | |
1649 | if (new_level != prev_level | |
1650 | || bidi_it->type == NEUTRAL_B) | |
1651 | { | |
1652 | /* We've got a new embedding level run, compute the directional | |
1653 | type of sor and initialize per-run variables (UAX#9, clause | |
1654 | X10). */ | |
1655 | bidi_set_sor_type (bidi_it, prev_level, new_level); | |
1656 | } | |
1657 | else if (type == NEUTRAL_S || type == NEUTRAL_WS | |
1658 | || type == WEAK_BN || type == STRONG_AL) | |
89d3374a EZ |
1659 | bidi_it->type_after_w1 = type; /* needed in L1 */ |
1660 | bidi_check_type (bidi_it->type_after_w1); | |
b7b65b15 EZ |
1661 | |
1662 | /* Level and directional override status are already recorded in | |
1663 | bidi_it, and do not need any change; see X6. */ | |
1664 | if (override == R2L) /* X6 */ | |
1665 | type = STRONG_R; | |
1666 | else if (override == L2R) | |
1667 | type = STRONG_L; | |
bc5a45f3 | 1668 | else |
b7b65b15 | 1669 | { |
bc5a45f3 | 1670 | if (type == WEAK_NSM) /* W1 */ |
b7b65b15 | 1671 | { |
bc5a45f3 | 1672 | /* Note that we don't need to consider the case where the |
5930fe97 EZ |
1673 | prev character has its type overridden by an RLO or LRO, |
1674 | because then either the type of this NSM would have been | |
1675 | also overridden, or the previous character is outside the | |
1676 | current level run, and thus not relevant to this NSM. | |
1677 | This is why NSM gets the type_after_w1 of the previous | |
1678 | character. */ | |
ebb5722e EZ |
1679 | if (bidi_it->prev.type_after_w1 != UNKNOWN_BT |
1680 | /* if type_after_w1 is NEUTRAL_B, this NSM is at sor */ | |
1681 | && bidi_it->prev.type_after_w1 != NEUTRAL_B) | |
5930fe97 | 1682 | type = bidi_it->prev.type_after_w1; |
bc5a45f3 EZ |
1683 | else if (bidi_it->sor == R2L) |
1684 | type = STRONG_R; | |
1685 | else if (bidi_it->sor == L2R) | |
1686 | type = STRONG_L; | |
1687 | else /* shouldn't happen! */ | |
1088b922 | 1688 | emacs_abort (); |
b7b65b15 | 1689 | } |
bc5a45f3 EZ |
1690 | if (type == WEAK_EN /* W2 */ |
1691 | && bidi_it->last_strong.type_after_w1 == STRONG_AL) | |
1692 | type = WEAK_AN; | |
1693 | else if (type == STRONG_AL) /* W3 */ | |
1694 | type = STRONG_R; | |
1695 | else if ((type == WEAK_ES /* W4 */ | |
1696 | && bidi_it->prev.type_after_w1 == WEAK_EN | |
1697 | && bidi_it->prev.orig_type == WEAK_EN) | |
1698 | || (type == WEAK_CS | |
1699 | && ((bidi_it->prev.type_after_w1 == WEAK_EN | |
1700 | && bidi_it->prev.orig_type == WEAK_EN) | |
1701 | || bidi_it->prev.type_after_w1 == WEAK_AN))) | |
b7b65b15 | 1702 | { |
512a289d RS |
1703 | const unsigned char *s |
1704 | = (STRINGP (bidi_it->string.lstring) | |
1705 | ? SDATA (bidi_it->string.lstring) | |
1706 | : bidi_it->string.s); | |
1707 | ||
1708 | next_char = (bidi_it->charpos + bidi_it->nchars >= eob | |
1709 | ? BIDI_EOB | |
1710 | : bidi_char_at_pos (bidi_it->bytepos + bidi_it->ch_len, | |
1711 | s, bidi_it->string.unibyte)); | |
6bff6497 | 1712 | type_of_next = bidi_get_type (next_char, override); |
b7b65b15 | 1713 | |
bc5a45f3 | 1714 | if (type_of_next == WEAK_BN |
b7b65b15 EZ |
1715 | || bidi_explicit_dir_char (next_char)) |
1716 | { | |
1717 | bidi_copy_it (&saved_it, bidi_it); | |
1718 | while (bidi_resolve_explicit (bidi_it) == new_level | |
bc5a45f3 | 1719 | && bidi_it->type == WEAK_BN) |
b7b65b15 EZ |
1720 | ; |
1721 | type_of_next = bidi_it->type; | |
b7b65b15 EZ |
1722 | bidi_copy_it (bidi_it, &saved_it); |
1723 | } | |
bc5a45f3 EZ |
1724 | |
1725 | /* If the next character is EN, but the last strong-type | |
1726 | character is AL, that next EN will be changed to AN when | |
1727 | we process it in W2 above. So in that case, this ES | |
1728 | should not be changed into EN. */ | |
1729 | if (type == WEAK_ES | |
1730 | && type_of_next == WEAK_EN | |
1731 | && bidi_it->last_strong.type_after_w1 != STRONG_AL) | |
1732 | type = WEAK_EN; | |
1733 | else if (type == WEAK_CS) | |
b7b65b15 | 1734 | { |
bc5a45f3 EZ |
1735 | if (bidi_it->prev.type_after_w1 == WEAK_AN |
1736 | && (type_of_next == WEAK_AN | |
1737 | /* If the next character is EN, but the last | |
1738 | strong-type character is AL, EN will be later | |
1739 | changed to AN when we process it in W2 above. | |
1740 | So in that case, this ES should not be | |
1741 | changed into EN. */ | |
1742 | || (type_of_next == WEAK_EN | |
1743 | && bidi_it->last_strong.type_after_w1 == STRONG_AL))) | |
1744 | type = WEAK_AN; | |
1745 | else if (bidi_it->prev.type_after_w1 == WEAK_EN | |
1746 | && type_of_next == WEAK_EN | |
1747 | && bidi_it->last_strong.type_after_w1 != STRONG_AL) | |
1748 | type = WEAK_EN; | |
1749 | } | |
1750 | } | |
1751 | else if (type == WEAK_ET /* W5: ET with EN before or after it */ | |
1752 | || type == WEAK_BN) /* W5/Retaining */ | |
1753 | { | |
7b5d6677 | 1754 | if (bidi_it->prev.type_after_w1 == WEAK_EN) /* ET/BN w/EN before it */ |
bc5a45f3 | 1755 | type = WEAK_EN; |
7b5d6677 EZ |
1756 | else if (bidi_it->next_en_pos > bidi_it->charpos |
1757 | && bidi_it->next_en_type != WEAK_BN) | |
1758 | { | |
1759 | if (bidi_it->next_en_type == WEAK_EN) /* ET/BN with EN after it */ | |
1760 | type = WEAK_EN; | |
1761 | } | |
1762 | else if (bidi_it->next_en_pos >=0) | |
bc5a45f3 | 1763 | { |
d311d28c | 1764 | ptrdiff_t en_pos = bidi_it->charpos + bidi_it->nchars; |
512a289d RS |
1765 | const unsigned char *s = (STRINGP (bidi_it->string.lstring) |
1766 | ? SDATA (bidi_it->string.lstring) | |
1767 | : bidi_it->string.s); | |
bc5a45f3 | 1768 | |
102ebb00 | 1769 | if (bidi_it->nchars <= 0) |
1088b922 | 1770 | emacs_abort (); |
512a289d RS |
1771 | next_char |
1772 | = (bidi_it->charpos + bidi_it->nchars >= eob | |
1773 | ? BIDI_EOB | |
1774 | : bidi_char_at_pos (bidi_it->bytepos + bidi_it->ch_len, s, | |
1775 | bidi_it->string.unibyte)); | |
bc5a45f3 EZ |
1776 | type_of_next = bidi_get_type (next_char, override); |
1777 | ||
1778 | if (type_of_next == WEAK_ET | |
1779 | || type_of_next == WEAK_BN | |
1780 | || bidi_explicit_dir_char (next_char)) | |
1781 | { | |
1782 | bidi_copy_it (&saved_it, bidi_it); | |
1783 | while (bidi_resolve_explicit (bidi_it) == new_level | |
1784 | && (bidi_it->type == WEAK_BN | |
1785 | || bidi_it->type == WEAK_ET)) | |
1786 | ; | |
1787 | type_of_next = bidi_it->type; | |
1788 | en_pos = bidi_it->charpos; | |
1789 | bidi_copy_it (bidi_it, &saved_it); | |
1790 | } | |
7b5d6677 EZ |
1791 | /* Remember this position, to speed up processing of the |
1792 | next ETs. */ | |
1793 | bidi_it->next_en_pos = en_pos; | |
bc5a45f3 | 1794 | if (type_of_next == WEAK_EN) |
b7b65b15 | 1795 | { |
bc5a45f3 EZ |
1796 | /* If the last strong character is AL, the EN we've |
1797 | found will become AN when we get to it (W2). */ | |
7b5d6677 EZ |
1798 | if (bidi_it->last_strong.type_after_w1 == STRONG_AL) |
1799 | type_of_next = WEAK_AN; | |
bc5a45f3 EZ |
1800 | else if (type == WEAK_BN) |
1801 | type = NEUTRAL_ON; /* W6/Retaining */ | |
7b5d6677 EZ |
1802 | else |
1803 | type = WEAK_EN; | |
b7b65b15 | 1804 | } |
4787455f EZ |
1805 | else if (type_of_next == NEUTRAL_B) |
1806 | /* Record the fact that there are no more ENs from | |
1807 | here to the end of paragraph, to avoid entering the | |
1808 | loop above ever again in this paragraph. */ | |
1809 | bidi_it->next_en_pos = -1; | |
7b5d6677 EZ |
1810 | /* Record the type of the character where we ended our search. */ |
1811 | bidi_it->next_en_type = type_of_next; | |
b7b65b15 EZ |
1812 | } |
1813 | } | |
1814 | } | |
1815 | ||
1816 | if (type == WEAK_ES || type == WEAK_ET || type == WEAK_CS /* W6 */ | |
89d3374a EZ |
1817 | || (type == WEAK_BN |
1818 | && (bidi_it->prev.type_after_w1 == WEAK_CS /* W6/Retaining */ | |
1819 | || bidi_it->prev.type_after_w1 == WEAK_ES | |
1820 | || bidi_it->prev.type_after_w1 == WEAK_ET))) | |
b7b65b15 EZ |
1821 | type = NEUTRAL_ON; |
1822 | ||
1823 | /* Store the type we've got so far, before we clobber it with strong | |
1824 | types in W7 and while resolving neutral types. But leave alone | |
1825 | the original types that were recorded above, because we will need | |
1826 | them for the L1 clause. */ | |
89d3374a EZ |
1827 | if (bidi_it->type_after_w1 == UNKNOWN_BT) |
1828 | bidi_it->type_after_w1 = type; | |
1829 | bidi_check_type (bidi_it->type_after_w1); | |
b7b65b15 EZ |
1830 | |
1831 | if (type == WEAK_EN) /* W7 */ | |
1832 | { | |
89d3374a | 1833 | if ((bidi_it->last_strong.type_after_w1 == STRONG_L) |
b7b65b15 EZ |
1834 | || (bidi_it->last_strong.type == UNKNOWN_BT && bidi_it->sor == L2R)) |
1835 | type = STRONG_L; | |
1836 | } | |
1837 | ||
1838 | bidi_it->type = type; | |
2d6e4628 | 1839 | bidi_check_type (bidi_it->type); |
b7b65b15 EZ |
1840 | return type; |
1841 | } | |
1842 | ||
cbb09f04 EZ |
1843 | /* Resolve the type of a neutral character according to the type of |
1844 | surrounding strong text and the current embedding level. */ | |
0a99eee1 | 1845 | static bidi_type_t |
cbb09f04 EZ |
1846 | bidi_resolve_neutral_1 (bidi_type_t prev_type, bidi_type_t next_type, int lev) |
1847 | { | |
1848 | /* N1: European and Arabic numbers are treated as though they were R. */ | |
1849 | if (next_type == WEAK_EN || next_type == WEAK_AN) | |
1850 | next_type = STRONG_R; | |
1851 | if (prev_type == WEAK_EN || prev_type == WEAK_AN) | |
1852 | prev_type = STRONG_R; | |
1853 | ||
1854 | if (next_type == prev_type) /* N1 */ | |
1855 | return next_type; | |
1856 | else if ((lev & 1) == 0) /* N2 */ | |
1857 | return STRONG_L; | |
1858 | else | |
1859 | return STRONG_R; | |
1860 | } | |
1861 | ||
fd3998ff | 1862 | static bidi_type_t |
b7b65b15 EZ |
1863 | bidi_resolve_neutral (struct bidi_it *bidi_it) |
1864 | { | |
1865 | int prev_level = bidi_it->level_stack[bidi_it->stack_idx].level; | |
1866 | bidi_type_t type = bidi_resolve_weak (bidi_it); | |
1867 | int current_level = bidi_it->level_stack[bidi_it->stack_idx].level; | |
1868 | ||
1869 | if (!(type == STRONG_R | |
1870 | || type == STRONG_L | |
1871 | || type == WEAK_BN | |
1872 | || type == WEAK_EN | |
1873 | || type == WEAK_AN | |
1874 | || type == NEUTRAL_B | |
1875 | || type == NEUTRAL_S | |
1876 | || type == NEUTRAL_WS | |
1877 | || type == NEUTRAL_ON)) | |
1088b922 | 1878 | emacs_abort (); |
b7b65b15 | 1879 | |
4787455f EZ |
1880 | if ((type != NEUTRAL_B /* Don't risk entering the long loop below if |
1881 | we are already at paragraph end. */ | |
1882 | && bidi_get_category (type) == NEUTRAL) | |
b7b65b15 EZ |
1883 | || (type == WEAK_BN && prev_level == current_level)) |
1884 | { | |
1885 | if (bidi_it->next_for_neutral.type != UNKNOWN_BT) | |
1886 | type = bidi_resolve_neutral_1 (bidi_it->prev_for_neutral.type, | |
1887 | bidi_it->next_for_neutral.type, | |
1888 | current_level); | |
4787455f EZ |
1889 | /* The next two "else if" clauses are shortcuts for the |
1890 | important special case when we have a long sequence of | |
1891 | neutral or WEAK_BN characters, such as whitespace or nulls or | |
1892 | other control characters, on the base embedding level of the | |
1893 | paragraph, and that sequence goes all the way to the end of | |
1894 | the paragraph and follows a character whose resolved | |
1895 | directionality is identical to the base embedding level. | |
1896 | (This is what happens in a buffer with plain L2R text that | |
1897 | happens to include long sequences of control characters.) By | |
1898 | virtue of N1, the result of examining this long sequence will | |
1899 | always be either STRONG_L or STRONG_R, depending on the base | |
1900 | embedding level. So we use this fact directly instead of | |
1901 | entering the expensive loop in the "else" clause. */ | |
1902 | else if (current_level == 0 | |
1903 | && bidi_it->prev_for_neutral.type == STRONG_L | |
1904 | && !bidi_explicit_dir_char (bidi_it->ch)) | |
1905 | type = bidi_resolve_neutral_1 (bidi_it->prev_for_neutral.type, | |
1906 | STRONG_L, current_level); | |
1907 | else if (/* current level is 1 */ | |
1908 | current_level == 1 | |
1909 | /* base embedding level is also 1 */ | |
1910 | && bidi_it->level_stack[0].level == 1 | |
1911 | /* previous character is one of those considered R for | |
1912 | the purposes of W5 */ | |
1913 | && (bidi_it->prev_for_neutral.type == STRONG_R | |
1914 | || bidi_it->prev_for_neutral.type == WEAK_EN | |
1915 | || bidi_it->prev_for_neutral.type == WEAK_AN) | |
1916 | && !bidi_explicit_dir_char (bidi_it->ch)) | |
1917 | type = bidi_resolve_neutral_1 (bidi_it->prev_for_neutral.type, | |
1918 | STRONG_R, current_level); | |
b7b65b15 EZ |
1919 | else |
1920 | { | |
1921 | /* Arrrgh!! The UAX#9 algorithm is too deeply entrenched in | |
1922 | the assumption of batch-style processing; see clauses W4, | |
1923 | W5, and especially N1, which require to look far forward | |
182ce2d2 EZ |
1924 | (as well as back) in the buffer/string. May the fleas of |
1925 | a thousand camels infest the armpits of those who design | |
b7b65b15 EZ |
1926 | supposedly general-purpose algorithms by looking at their |
1927 | own implementations, and fail to consider other possible | |
1928 | implementations! */ | |
1929 | struct bidi_it saved_it; | |
1930 | bidi_type_t next_type; | |
1931 | ||
1932 | if (bidi_it->scan_dir == -1) | |
1088b922 | 1933 | emacs_abort (); |
b7b65b15 EZ |
1934 | |
1935 | bidi_copy_it (&saved_it, bidi_it); | |
1936 | /* Scan the text forward until we find the first non-neutral | |
1937 | character, and then use that to resolve the neutral we | |
1938 | are dealing with now. We also cache the scanned iterator | |
1939 | states, to salvage some of the effort later. */ | |
1940 | bidi_cache_iterator_state (bidi_it, 0); | |
1941 | do { | |
1942 | /* Record the info about the previous character, so that | |
1943 | it will be cached below with this state. */ | |
89d3374a | 1944 | if (bidi_it->type_after_w1 != WEAK_BN /* W1/Retaining */ |
b7b65b15 EZ |
1945 | && bidi_it->type != WEAK_BN) |
1946 | bidi_remember_char (&bidi_it->prev, bidi_it); | |
1947 | type = bidi_resolve_weak (bidi_it); | |
1948 | /* Paragraph separators have their levels fully resolved | |
1949 | at this point, so cache them as resolved. */ | |
1950 | bidi_cache_iterator_state (bidi_it, type == NEUTRAL_B); | |
1951 | /* FIXME: implement L1 here, by testing for a newline and | |
1952 | resetting the level for any sequence of whitespace | |
1953 | characters adjacent to it. */ | |
1954 | } while (!(type == NEUTRAL_B | |
1955 | || (type != WEAK_BN | |
1956 | && bidi_get_category (type) != NEUTRAL) | |
1957 | /* This is all per level run, so stop when we | |
1958 | reach the end of this level run. */ | |
512a289d RS |
1959 | || (bidi_it->level_stack[bidi_it->stack_idx].level |
1960 | != current_level))); | |
b7b65b15 EZ |
1961 | |
1962 | bidi_remember_char (&saved_it.next_for_neutral, bidi_it); | |
1963 | ||
1964 | switch (type) | |
1965 | { | |
1966 | case STRONG_L: | |
1967 | case STRONG_R: | |
1968 | case STRONG_AL: | |
4787455f EZ |
1969 | /* Actually, STRONG_AL cannot happen here, because |
1970 | bidi_resolve_weak converts it to STRONG_R, per W3. */ | |
a54e2c05 | 1971 | eassert (type != STRONG_AL); |
b7b65b15 EZ |
1972 | next_type = type; |
1973 | break; | |
1974 | case WEAK_EN: | |
1975 | case WEAK_AN: | |
1976 | /* N1: ``European and Arabic numbers are treated as | |
1977 | though they were R.'' */ | |
1978 | next_type = STRONG_R; | |
b7b65b15 EZ |
1979 | break; |
1980 | case WEAK_BN: | |
713bfeaa | 1981 | case NEUTRAL_ON: /* W6/Retaining */ |
b7b65b15 | 1982 | if (!bidi_explicit_dir_char (bidi_it->ch)) |
1088b922 | 1983 | emacs_abort (); /* can't happen: BNs are skipped */ |
b7b65b15 EZ |
1984 | /* FALLTHROUGH */ |
1985 | case NEUTRAL_B: | |
1986 | /* Marched all the way to the end of this level run. | |
1987 | We need to use the eor type, whose information is | |
1988 | stored by bidi_set_sor_type in the prev_for_neutral | |
1989 | member. */ | |
1990 | if (saved_it.type != WEAK_BN | |
89d3374a | 1991 | || bidi_get_category (bidi_it->prev.type_after_w1) == NEUTRAL) |
4787455f | 1992 | next_type = bidi_it->prev_for_neutral.type; |
b7b65b15 EZ |
1993 | else |
1994 | { | |
1995 | /* This is a BN which does not adjoin neutrals. | |
1996 | Leave its type alone. */ | |
1997 | bidi_copy_it (bidi_it, &saved_it); | |
1998 | return bidi_it->type; | |
1999 | } | |
2000 | break; | |
2001 | default: | |
1088b922 | 2002 | emacs_abort (); |
b7b65b15 EZ |
2003 | } |
2004 | type = bidi_resolve_neutral_1 (saved_it.prev_for_neutral.type, | |
2005 | next_type, current_level); | |
4787455f | 2006 | saved_it.next_for_neutral.type = next_type; |
b7b65b15 | 2007 | saved_it.type = type; |
4787455f | 2008 | bidi_check_type (next_type); |
2d6e4628 | 2009 | bidi_check_type (type); |
b7b65b15 EZ |
2010 | bidi_copy_it (bidi_it, &saved_it); |
2011 | } | |
2012 | } | |
2013 | return type; | |
2014 | } | |
2015 | ||
2016 | /* Given an iterator state in BIDI_IT, advance one character position | |
182ce2d2 EZ |
2017 | in the buffer/string to the next character (in the logical order), |
2018 | resolve the bidi type of that next character, and return that | |
2019 | type. */ | |
fd3998ff | 2020 | static bidi_type_t |
b7b65b15 EZ |
2021 | bidi_type_of_next_char (struct bidi_it *bidi_it) |
2022 | { | |
2023 | bidi_type_t type; | |
2024 | ||
2025 | /* This should always be called during a forward scan. */ | |
2026 | if (bidi_it->scan_dir != 1) | |
1088b922 | 2027 | emacs_abort (); |
b7b65b15 EZ |
2028 | |
2029 | /* Reset the limit until which to ignore BNs if we step out of the | |
2030 | area where we found only empty levels. */ | |
87e67904 | 2031 | if ((bidi_it->ignore_bn_limit > -1 |
b7b65b15 | 2032 | && bidi_it->ignore_bn_limit <= bidi_it->charpos) |
87e67904 | 2033 | || (bidi_it->ignore_bn_limit == -2 |
b7b65b15 | 2034 | && !bidi_explicit_dir_char (bidi_it->ch))) |
87e67904 | 2035 | bidi_it->ignore_bn_limit = -1; |
b7b65b15 EZ |
2036 | |
2037 | type = bidi_resolve_neutral (bidi_it); | |
2038 | ||
2039 | return type; | |
2040 | } | |
2041 | ||
2042 | /* Given an iterator state BIDI_IT, advance one character position in | |
182ce2d2 EZ |
2043 | the buffer/string to the next character (in the current scan |
2044 | direction), resolve the embedding and implicit levels of that next | |
2045 | character, and return the resulting level. */ | |
fd3998ff | 2046 | static int |
b7b65b15 EZ |
2047 | bidi_level_of_next_char (struct bidi_it *bidi_it) |
2048 | { | |
2049 | bidi_type_t type; | |
2050 | int level, prev_level = -1; | |
2051 | struct bidi_saved_info next_for_neutral; | |
d311d28c | 2052 | ptrdiff_t next_char_pos = -2; |
b7b65b15 EZ |
2053 | |
2054 | if (bidi_it->scan_dir == 1) | |
2055 | { | |
5895d7b9 | 2056 | ptrdiff_t eob |
512a289d RS |
2057 | = ((bidi_it->string.s || STRINGP (bidi_it->string.lstring)) |
2058 | ? bidi_it->string.schars : ZV); | |
9f257352 | 2059 | |
b7b65b15 | 2060 | /* There's no sense in trying to advance if we hit end of text. */ |
9f257352 | 2061 | if (bidi_it->charpos >= eob) |
b7b65b15 EZ |
2062 | return bidi_it->resolved_level; |
2063 | ||
2064 | /* Record the info about the previous character. */ | |
89d3374a | 2065 | if (bidi_it->type_after_w1 != WEAK_BN /* W1/Retaining */ |
b7b65b15 EZ |
2066 | && bidi_it->type != WEAK_BN) |
2067 | bidi_remember_char (&bidi_it->prev, bidi_it); | |
89d3374a EZ |
2068 | if (bidi_it->type_after_w1 == STRONG_R |
2069 | || bidi_it->type_after_w1 == STRONG_L | |
2070 | || bidi_it->type_after_w1 == STRONG_AL) | |
b7b65b15 EZ |
2071 | bidi_remember_char (&bidi_it->last_strong, bidi_it); |
2072 | /* FIXME: it sounds like we don't need both prev and | |
2073 | prev_for_neutral members, but I'm leaving them both for now. */ | |
2074 | if (bidi_it->type == STRONG_R || bidi_it->type == STRONG_L | |
2075 | || bidi_it->type == WEAK_EN || bidi_it->type == WEAK_AN) | |
2076 | bidi_remember_char (&bidi_it->prev_for_neutral, bidi_it); | |
2077 | ||
2078 | /* If we overstepped the characters used for resolving neutrals | |
2079 | and whitespace, invalidate their info in the iterator. */ | |
2080 | if (bidi_it->charpos >= bidi_it->next_for_neutral.charpos) | |
2081 | bidi_it->next_for_neutral.type = UNKNOWN_BT; | |
2082 | if (bidi_it->next_en_pos >= 0 | |
2083 | && bidi_it->charpos >= bidi_it->next_en_pos) | |
7b5d6677 EZ |
2084 | { |
2085 | bidi_it->next_en_pos = 0; | |
2086 | bidi_it->next_en_type = UNKNOWN_BT; | |
2087 | } | |
b7b65b15 EZ |
2088 | if (bidi_it->next_for_ws.type != UNKNOWN_BT |
2089 | && bidi_it->charpos >= bidi_it->next_for_ws.charpos) | |
2090 | bidi_it->next_for_ws.type = UNKNOWN_BT; | |
2091 | ||
2092 | /* This must be taken before we fill the iterator with the info | |
2093 | about the next char. If we scan backwards, the iterator | |
2094 | state must be already cached, so there's no need to know the | |
2095 | embedding level of the previous character, since we will be | |
2096 | returning to our caller shortly. */ | |
2097 | prev_level = bidi_it->level_stack[bidi_it->stack_idx].level; | |
2098 | } | |
2099 | next_for_neutral = bidi_it->next_for_neutral; | |
2100 | ||
182ce2d2 EZ |
2101 | /* Perhaps the character we want is already cached. If it is, the |
2102 | call to bidi_cache_find below will return a type other than | |
2103 | UNKNOWN_BT. */ | |
87e67904 | 2104 | if (bidi_cache_idx > bidi_cache_start && !bidi_it->first_elt) |
102ebb00 | 2105 | { |
512a289d RS |
2106 | int bob = ((bidi_it->string.s || STRINGP (bidi_it->string.lstring)) |
2107 | ? 0 : 1); | |
102ebb00 EZ |
2108 | if (bidi_it->scan_dir > 0) |
2109 | { | |
2110 | if (bidi_it->nchars <= 0) | |
1088b922 | 2111 | emacs_abort (); |
102ebb00 EZ |
2112 | next_char_pos = bidi_it->charpos + bidi_it->nchars; |
2113 | } | |
9f257352 | 2114 | else if (bidi_it->charpos >= bob) |
bb269206 EZ |
2115 | /* Implementation note: we allow next_char_pos to be as low as |
2116 | 0 for buffers or -1 for strings, and that is okay because | |
2117 | that's the "position" of the sentinel iterator state we | |
2118 | cached at the beginning of the iteration. */ | |
102ebb00 | 2119 | next_char_pos = bidi_it->charpos - 1; |
578b494e | 2120 | if (next_char_pos >= bob - 1) |
87e67904 EZ |
2121 | type = bidi_cache_find (next_char_pos, -1, bidi_it); |
2122 | else | |
2123 | type = UNKNOWN_BT; | |
102ebb00 | 2124 | } |
182ce2d2 | 2125 | else |
102ebb00 | 2126 | type = UNKNOWN_BT; |
b7b65b15 EZ |
2127 | if (type != UNKNOWN_BT) |
2128 | { | |
2129 | /* Don't lose the information for resolving neutrals! The | |
2130 | cached states could have been cached before their | |
2131 | next_for_neutral member was computed. If we are on our way | |
2132 | forward, we can simply take the info from the previous | |
2133 | state. */ | |
2134 | if (bidi_it->scan_dir == 1 | |
2135 | && bidi_it->next_for_neutral.type == UNKNOWN_BT) | |
2136 | bidi_it->next_for_neutral = next_for_neutral; | |
2137 | ||
2138 | /* If resolved_level is -1, it means this state was cached | |
2139 | before it was completely resolved, so we cannot return | |
2140 | it. */ | |
2141 | if (bidi_it->resolved_level != -1) | |
2142 | return bidi_it->resolved_level; | |
2143 | } | |
2144 | if (bidi_it->scan_dir == -1) | |
2145 | /* If we are going backwards, the iterator state is already cached | |
2146 | from previous scans, and should be fully resolved. */ | |
1088b922 | 2147 | emacs_abort (); |
b7b65b15 EZ |
2148 | |
2149 | if (type == UNKNOWN_BT) | |
2150 | type = bidi_type_of_next_char (bidi_it); | |
2151 | ||
2152 | if (type == NEUTRAL_B) | |
2153 | return bidi_it->resolved_level; | |
2154 | ||
2155 | level = bidi_it->level_stack[bidi_it->stack_idx].level; | |
2156 | if ((bidi_get_category (type) == NEUTRAL /* && type != NEUTRAL_B */) | |
2157 | || (type == WEAK_BN && prev_level == level)) | |
2158 | { | |
2159 | if (bidi_it->next_for_neutral.type == UNKNOWN_BT) | |
1088b922 | 2160 | emacs_abort (); |
b7b65b15 EZ |
2161 | |
2162 | /* If the cached state shows a neutral character, it was not | |
2163 | resolved by bidi_resolve_neutral, so do it now. */ | |
2164 | type = bidi_resolve_neutral_1 (bidi_it->prev_for_neutral.type, | |
2165 | bidi_it->next_for_neutral.type, | |
2166 | level); | |
2167 | } | |
2168 | ||
2169 | if (!(type == STRONG_R | |
2170 | || type == STRONG_L | |
2171 | || type == WEAK_BN | |
2172 | || type == WEAK_EN | |
2173 | || type == WEAK_AN)) | |
1088b922 | 2174 | emacs_abort (); |
b7b65b15 | 2175 | bidi_it->type = type; |
2d6e4628 | 2176 | bidi_check_type (bidi_it->type); |
b7b65b15 EZ |
2177 | |
2178 | /* For L1 below, we need to know, for each WS character, whether | |
0d327994 | 2179 | it belongs to a sequence of WS characters preceding a newline |
b7b65b15 | 2180 | or a TAB or a paragraph separator. */ |
89d3374a | 2181 | if (bidi_it->orig_type == NEUTRAL_WS |
b7b65b15 EZ |
2182 | && bidi_it->next_for_ws.type == UNKNOWN_BT) |
2183 | { | |
2184 | int ch; | |
d311d28c PE |
2185 | ptrdiff_t clen = bidi_it->ch_len; |
2186 | ptrdiff_t bpos = bidi_it->bytepos; | |
2187 | ptrdiff_t cpos = bidi_it->charpos; | |
2188 | ptrdiff_t disp_pos = bidi_it->disp_pos; | |
2189 | ptrdiff_t nc = bidi_it->nchars; | |
87e67904 | 2190 | struct bidi_string_data bs = bidi_it->string; |
b7b65b15 | 2191 | bidi_type_t chtype; |
2cc21167 | 2192 | bool fwp = bidi_it->frame_window_p; |
0c95fcf7 | 2193 | int dpp = bidi_it->disp_prop; |
b7b65b15 | 2194 | |
102ebb00 | 2195 | if (bidi_it->nchars <= 0) |
1088b922 | 2196 | emacs_abort (); |
b7b65b15 | 2197 | do { |
36075a19 | 2198 | ch = bidi_fetch_char (cpos += nc, bpos += clen, &disp_pos, &dpp, &bs, |
5bf97bfc | 2199 | bidi_it->w, fwp, &clen, &nc); |
79beb178 | 2200 | if (ch == '\n' || ch == BIDI_EOB) |
b7b65b15 EZ |
2201 | chtype = NEUTRAL_B; |
2202 | else | |
6bff6497 | 2203 | chtype = bidi_get_type (ch, NEUTRAL_DIR); |
b7b65b15 EZ |
2204 | } while (chtype == NEUTRAL_WS || chtype == WEAK_BN |
2205 | || bidi_explicit_dir_char (ch)); /* L1/Retaining */ | |
2206 | bidi_it->next_for_ws.type = chtype; | |
2d6e4628 | 2207 | bidi_check_type (bidi_it->next_for_ws.type); |
b7b65b15 EZ |
2208 | bidi_it->next_for_ws.charpos = cpos; |
2209 | bidi_it->next_for_ws.bytepos = bpos; | |
2210 | } | |
2211 | ||
2212 | /* Resolve implicit levels, with a twist: PDFs get the embedding | |
55622b93 | 2213 | level of the embedding they terminate. See below for the |
b7b65b15 | 2214 | reason. */ |
89d3374a | 2215 | if (bidi_it->orig_type == PDF |
b7b65b15 EZ |
2216 | /* Don't do this if this formatting code didn't change the |
2217 | embedding level due to invalid or empty embeddings. */ | |
2218 | && prev_level != level) | |
2219 | { | |
2220 | /* Don't look in UAX#9 for the reason for this: it's our own | |
2221 | private quirk. The reason is that we want the formatting | |
2222 | codes to be delivered so that they bracket the text of their | |
2223 | embedding. For example, given the text | |
2224 | ||
2225 | {RLO}teST{PDF} | |
2226 | ||
2227 | we want it to be displayed as | |
2228 | ||
0d68907d | 2229 | {PDF}STet{RLO} |
b7b65b15 EZ |
2230 | |
2231 | not as | |
2232 | ||
2233 | STet{RLO}{PDF} | |
2234 | ||
2235 | which will result because we bump up the embedding level as | |
2236 | soon as we see the RLO and pop it as soon as we see the PDF, | |
2237 | so RLO itself has the same embedding level as "teST", and | |
2238 | thus would be normally delivered last, just before the PDF. | |
2239 | The switch below fiddles with the level of PDF so that this | |
2240 | ugly side effect does not happen. | |
2241 | ||
2242 | (This is, of course, only important if the formatting codes | |
e7402cb2 EZ |
2243 | are actually displayed, but Emacs does need to display them |
2244 | if the user wants to.) */ | |
b7b65b15 EZ |
2245 | level = prev_level; |
2246 | } | |
89d3374a EZ |
2247 | else if (bidi_it->orig_type == NEUTRAL_B /* L1 */ |
2248 | || bidi_it->orig_type == NEUTRAL_S | |
e7402cb2 | 2249 | || bidi_it->ch == '\n' || bidi_it->ch == BIDI_EOB |
89d3374a | 2250 | || (bidi_it->orig_type == NEUTRAL_WS |
b7b65b15 EZ |
2251 | && (bidi_it->next_for_ws.type == NEUTRAL_B |
2252 | || bidi_it->next_for_ws.type == NEUTRAL_S))) | |
2253 | level = bidi_it->level_stack[0].level; | |
2254 | else if ((level & 1) == 0) /* I1 */ | |
2255 | { | |
2256 | if (type == STRONG_R) | |
2257 | level++; | |
2258 | else if (type == WEAK_EN || type == WEAK_AN) | |
2259 | level += 2; | |
2260 | } | |
2261 | else /* I2 */ | |
2262 | { | |
2263 | if (type == STRONG_L || type == WEAK_EN || type == WEAK_AN) | |
2264 | level++; | |
2265 | } | |
2266 | ||
2267 | bidi_it->resolved_level = level; | |
2268 | return level; | |
2269 | } | |
2270 | ||
2cc21167 PE |
2271 | /* Move to the other edge of a level given by LEVEL. If END_FLAG, |
2272 | we are at the end of a level, and we need to prepare to | |
b7b65b15 EZ |
2273 | resume the scan of the lower level. |
2274 | ||
2275 | If this level's other edge is cached, we simply jump to it, filling | |
2276 | the iterator structure with the iterator state on the other edge. | |
182ce2d2 EZ |
2277 | Otherwise, we walk the buffer or string until we come back to the |
2278 | same level as LEVEL. | |
b7b65b15 EZ |
2279 | |
2280 | Note: we are not talking here about a ``level run'' in the UAX#9 | |
2281 | sense of the term, but rather about a ``level'' which includes | |
2282 | all the levels higher than it. In other words, given the levels | |
2283 | like this: | |
2284 | ||
2285 | 11111112222222333333334443343222222111111112223322111 | |
2286 | A B C | |
2287 | ||
2288 | and assuming we are at point A scanning left to right, this | |
2289 | function moves to point C, whereas the UAX#9 ``level 2 run'' ends | |
2290 | at point B. */ | |
2291 | static void | |
2cc21167 | 2292 | bidi_find_other_level_edge (struct bidi_it *bidi_it, int level, bool end_flag) |
b7b65b15 EZ |
2293 | { |
2294 | int dir = end_flag ? -bidi_it->scan_dir : bidi_it->scan_dir; | |
39e378da | 2295 | ptrdiff_t idx; |
b7b65b15 EZ |
2296 | |
2297 | /* Try the cache first. */ | |
87e67904 EZ |
2298 | if ((idx = bidi_cache_find_level_change (level, dir, end_flag)) |
2299 | >= bidi_cache_start) | |
b7b65b15 EZ |
2300 | bidi_cache_fetch_state (idx, bidi_it); |
2301 | else | |
2302 | { | |
2303 | int new_level; | |
2304 | ||
1088b922 | 2305 | /* If we are at end of level, its edges must be cached. */ |
b7b65b15 | 2306 | if (end_flag) |
1088b922 | 2307 | emacs_abort (); |
b7b65b15 EZ |
2308 | |
2309 | bidi_cache_iterator_state (bidi_it, 1); | |
2310 | do { | |
2311 | new_level = bidi_level_of_next_char (bidi_it); | |
2312 | bidi_cache_iterator_state (bidi_it, 1); | |
2313 | } while (new_level >= level); | |
2314 | } | |
2315 | } | |
2316 | ||
2317 | void | |
4b292a22 | 2318 | bidi_move_to_visually_next (struct bidi_it *bidi_it) |
b7b65b15 EZ |
2319 | { |
2320 | int old_level, new_level, next_level; | |
9c82e145 | 2321 | struct bidi_it sentinel; |
acb28818 | 2322 | struct gcpro gcpro1; |
b7b65b15 | 2323 | |
87e67904 | 2324 | if (bidi_it->charpos < 0 || bidi_it->bytepos < 0) |
1088b922 | 2325 | emacs_abort (); |
b7b65b15 EZ |
2326 | |
2327 | if (bidi_it->scan_dir == 0) | |
2328 | { | |
2329 | bidi_it->scan_dir = 1; /* default to logical order */ | |
2330 | } | |
2331 | ||
acb28818 | 2332 | /* The code below can call eval, and thus cause GC. If we are |
7e2ad32c | 2333 | iterating a Lisp string, make sure it won't be GCed. */ |
acb28818 EZ |
2334 | if (STRINGP (bidi_it->string.lstring)) |
2335 | GCPRO1 (bidi_it->string.lstring); | |
2336 | ||
be39f003 | 2337 | /* If we just passed a newline, initialize for the next line. */ |
1137e8b8 EZ |
2338 | if (!bidi_it->first_elt |
2339 | && (bidi_it->ch == '\n' || bidi_it->ch == BIDI_EOB)) | |
be39f003 EZ |
2340 | bidi_line_init (bidi_it); |
2341 | ||
6dcfd253 EZ |
2342 | /* Prepare the sentinel iterator state, and cache it. When we bump |
2343 | into it, scanning backwards, we'll know that the last non-base | |
2344 | level is exhausted. */ | |
87e67904 | 2345 | if (bidi_cache_idx == bidi_cache_start) |
9c82e145 EZ |
2346 | { |
2347 | bidi_copy_it (&sentinel, bidi_it); | |
2348 | if (bidi_it->first_elt) | |
2349 | { | |
2350 | sentinel.charpos--; /* cached charpos needs to be monotonic */ | |
2351 | sentinel.bytepos--; | |
2352 | sentinel.ch = '\n'; /* doesn't matter, but why not? */ | |
2353 | sentinel.ch_len = 1; | |
182ce2d2 | 2354 | sentinel.nchars = 1; |
9c82e145 | 2355 | } |
6dcfd253 | 2356 | bidi_cache_iterator_state (&sentinel, 1); |
9c82e145 | 2357 | } |
b7b65b15 EZ |
2358 | |
2359 | old_level = bidi_it->resolved_level; | |
2360 | new_level = bidi_level_of_next_char (bidi_it); | |
b7b65b15 EZ |
2361 | |
2362 | /* Reordering of resolved levels (clause L2) is implemented by | |
2363 | jumping to the other edge of the level and flipping direction of | |
c0546589 | 2364 | scanning the text whenever we find a level change. */ |
b7b65b15 EZ |
2365 | if (new_level != old_level) |
2366 | { | |
2cc21167 | 2367 | bool ascending = new_level > old_level; |
b7b65b15 EZ |
2368 | int level_to_search = ascending ? old_level + 1 : old_level; |
2369 | int incr = ascending ? 1 : -1; | |
2370 | int expected_next_level = old_level + incr; | |
2371 | ||
b7b65b15 EZ |
2372 | /* Jump (or walk) to the other edge of this level. */ |
2373 | bidi_find_other_level_edge (bidi_it, level_to_search, !ascending); | |
2374 | /* Switch scan direction and peek at the next character in the | |
2375 | new direction. */ | |
2376 | bidi_it->scan_dir = -bidi_it->scan_dir; | |
2377 | ||
2378 | /* The following loop handles the case where the resolved level | |
2379 | jumps by more than one. This is typical for numbers inside a | |
2380 | run of text with left-to-right embedding direction, but can | |
2381 | also happen in other situations. In those cases the decision | |
2382 | where to continue after a level change, and in what direction, | |
2383 | is tricky. For example, given a text like below: | |
2384 | ||
2385 | abcdefgh | |
2386 | 11336622 | |
2387 | ||
2388 | (where the numbers below the text show the resolved levels), | |
2389 | the result of reordering according to UAX#9 should be this: | |
2390 | ||
2391 | efdcghba | |
2392 | ||
2393 | This is implemented by the loop below which flips direction | |
2394 | and jumps to the other edge of the level each time it finds | |
2395 | the new level not to be the expected one. The expected level | |
2396 | is always one more or one less than the previous one. */ | |
2397 | next_level = bidi_peek_at_next_level (bidi_it); | |
2398 | while (next_level != expected_next_level) | |
2399 | { | |
713bfeaa EZ |
2400 | /* If next_level is -1, it means we have an unresolved level |
2401 | in the cache, which at this point should not happen. If | |
2402 | it does, we will infloop. */ | |
2403 | eassert (next_level >= 0); | |
b7b65b15 EZ |
2404 | expected_next_level += incr; |
2405 | level_to_search += incr; | |
2406 | bidi_find_other_level_edge (bidi_it, level_to_search, !ascending); | |
2407 | bidi_it->scan_dir = -bidi_it->scan_dir; | |
2408 | next_level = bidi_peek_at_next_level (bidi_it); | |
2409 | } | |
2410 | ||
2411 | /* Finally, deliver the next character in the new direction. */ | |
2412 | next_level = bidi_level_of_next_char (bidi_it); | |
2413 | } | |
2414 | ||
b44d9321 EZ |
2415 | /* Take note when we have just processed the newline that precedes |
2416 | the end of the paragraph. The next time we are about to be | |
2417 | called, set_iterator_to_next will automatically reinit the | |
2418 | paragraph direction, if needed. We do this at the newline before | |
2419 | the paragraph separator, because the next character might not be | |
2420 | the first character of the next paragraph, due to the bidi | |
c0546589 EZ |
2421 | reordering, whereas we _must_ know the paragraph base direction |
2422 | _before_ we process the paragraph's text, since the base | |
2423 | direction affects the reordering. */ | |
1137e8b8 EZ |
2424 | if (bidi_it->scan_dir == 1 |
2425 | && (bidi_it->ch == '\n' || bidi_it->ch == BIDI_EOB)) | |
be39f003 | 2426 | { |
87e67904 EZ |
2427 | /* The paragraph direction of the entire string, once |
2428 | determined, is in effect for the entire string. Setting the | |
2429 | separator limit to the end of the string prevents | |
2430 | bidi_paragraph_init from being called automatically on this | |
2431 | string. */ | |
9f257352 | 2432 | if (bidi_it->string.s || STRINGP (bidi_it->string.lstring)) |
87e67904 EZ |
2433 | bidi_it->separator_limit = bidi_it->string.schars; |
2434 | else if (bidi_it->bytepos < ZV_BYTE) | |
be39f003 | 2435 | { |
5895d7b9 | 2436 | ptrdiff_t sep_len |
512a289d RS |
2437 | = bidi_at_paragraph_end (bidi_it->charpos + bidi_it->nchars, |
2438 | bidi_it->bytepos + bidi_it->ch_len); | |
87e67904 | 2439 | if (bidi_it->nchars <= 0) |
1088b922 | 2440 | emacs_abort (); |
87e67904 EZ |
2441 | if (sep_len >= 0) |
2442 | { | |
2443 | bidi_it->new_paragraph = 1; | |
2444 | /* Record the buffer position of the last character of the | |
2445 | paragraph separator. */ | |
512a289d RS |
2446 | bidi_it->separator_limit |
2447 | = bidi_it->charpos + bidi_it->nchars + sep_len; | |
87e67904 | 2448 | } |
be39f003 EZ |
2449 | } |
2450 | } | |
6bff6497 | 2451 | |
87e67904 | 2452 | if (bidi_it->scan_dir == 1 && bidi_cache_idx > bidi_cache_start) |
b7b65b15 EZ |
2453 | { |
2454 | /* If we are at paragraph's base embedding level and beyond the | |
2455 | last cached position, the cache's job is done and we can | |
2456 | discard it. */ | |
2457 | if (bidi_it->resolved_level == bidi_it->level_stack[0].level | |
182ce2d2 EZ |
2458 | && bidi_it->charpos > (bidi_cache[bidi_cache_idx - 1].charpos |
2459 | + bidi_cache[bidi_cache_idx - 1].nchars - 1)) | |
b7b65b15 EZ |
2460 | bidi_cache_reset (); |
2461 | /* But as long as we are caching during forward scan, we must | |
2462 | cache each state, or else the cache integrity will be | |
2463 | compromised: it assumes cached states correspond to buffer | |
2464 | positions 1:1. */ | |
2465 | else | |
2466 | bidi_cache_iterator_state (bidi_it, 1); | |
2467 | } | |
acb28818 EZ |
2468 | |
2469 | if (STRINGP (bidi_it->string.lstring)) | |
2470 | UNGCPRO; | |
b7b65b15 EZ |
2471 | } |
2472 | ||
2473 | /* This is meant to be called from within the debugger, whenever you | |
2474 | wish to examine the cache contents. */ | |
e78aecca | 2475 | void bidi_dump_cached_states (void) EXTERNALLY_VISIBLE; |
b7b65b15 EZ |
2476 | void |
2477 | bidi_dump_cached_states (void) | |
2478 | { | |
39e378da | 2479 | ptrdiff_t i; |
b7b65b15 EZ |
2480 | int ndigits = 1; |
2481 | ||
2482 | if (bidi_cache_idx == 0) | |
2483 | { | |
2484 | fprintf (stderr, "The cache is empty.\n"); | |
2485 | return; | |
2486 | } | |
df9733bf | 2487 | fprintf (stderr, "Total of %"pD"d state%s in cache:\n", |
b7b65b15 EZ |
2488 | bidi_cache_idx, bidi_cache_idx == 1 ? "" : "s"); |
2489 | ||
2490 | for (i = bidi_cache[bidi_cache_idx - 1].charpos; i > 0; i /= 10) | |
2491 | ndigits++; | |
2492 | fputs ("ch ", stderr); | |
2493 | for (i = 0; i < bidi_cache_idx; i++) | |
2494 | fprintf (stderr, "%*c", ndigits, bidi_cache[i].ch); | |
2495 | fputs ("\n", stderr); | |
2496 | fputs ("lvl ", stderr); | |
2497 | for (i = 0; i < bidi_cache_idx; i++) | |
2498 | fprintf (stderr, "%*d", ndigits, bidi_cache[i].resolved_level); | |
2499 | fputs ("\n", stderr); | |
2500 | fputs ("pos ", stderr); | |
2501 | for (i = 0; i < bidi_cache_idx; i++) | |
7c85f529 | 2502 | fprintf (stderr, "%*"pD"d", ndigits, bidi_cache[i].charpos); |
b7b65b15 EZ |
2503 | fputs ("\n", stderr); |
2504 | } |