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cbb09f04 | 1 | /* Low-level bidirectional buffer/string-scanning functions for GNU Emacs. |
acaf905b | 2 | Copyright (C) 2000-2001, 2004-2005, 2009-2012 |
b118e65f | 3 | Free Software Foundation, Inc. |
b7b65b15 EZ |
4 | |
5 | This file is part of GNU Emacs. | |
6 | ||
a8d11bd3 | 7 | GNU Emacs is free software: you can redistribute it and/or modify |
b7b65b15 | 8 | it under the terms of the GNU General Public License as published by |
a8d11bd3 EZ |
9 | the Free Software Foundation, either version 3 of the License, or |
10 | (at your option) any later version. | |
b7b65b15 EZ |
11 | |
12 | GNU Emacs is distributed in the hope that it will be useful, | |
13 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | GNU General Public License for more details. | |
16 | ||
b7b65b15 | 17 | You should have received a copy of the GNU General Public License |
a8d11bd3 | 18 | along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. */ |
b7b65b15 | 19 | |
2d6e4628 EZ |
20 | /* Written by Eli Zaretskii <eliz@gnu.org>. |
21 | ||
22 | A sequential implementation of the Unicode Bidirectional algorithm, | |
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 EZ |
59 | #include <setjmp.h> |
60 | ||
b7b65b15 | 61 | #include "lisp.h" |
b7b65b15 | 62 | #include "character.h" |
e5560ff7 | 63 | #include "buffer.h" |
b7b65b15 EZ |
64 | #include "dispextern.h" |
65 | ||
2cc21167 | 66 | static bool bidi_initialized = 0; |
b7b65b15 | 67 | |
cbc4fd20 | 68 | static Lisp_Object bidi_type_table, bidi_mirror_table; |
b7b65b15 EZ |
69 | |
70 | #define LRM_CHAR 0x200E | |
71 | #define RLM_CHAR 0x200F | |
b7b65b15 | 72 | #define BIDI_EOB -1 |
b7b65b15 | 73 | |
b7b65b15 EZ |
74 | /* Data type for describing the bidirectional character categories. */ |
75 | typedef enum { | |
76 | UNKNOWN_BC, | |
77 | NEUTRAL, | |
78 | WEAK, | |
79 | STRONG | |
80 | } bidi_category_t; | |
81 | ||
32413314 EZ |
82 | /* UAX#9 says to search only for L, AL, or R types of characters, and |
83 | ignore RLE, RLO, LRE, and LRO, when determining the base paragraph | |
84 | level. Yudit indeed ignores them. This variable is therefore set | |
2cc21167 PE |
85 | by default to ignore them, but clearing it will take them into |
86 | account. */ | |
87 | extern bool bidi_ignore_explicit_marks_for_paragraph_level EXTERNALLY_VISIBLE; | |
88 | bool bidi_ignore_explicit_marks_for_paragraph_level = 1; | |
b7b65b15 | 89 | |
372b7a95 | 90 | static Lisp_Object paragraph_start_re, paragraph_separate_re; |
6bff6497 | 91 | static Lisp_Object Qparagraph_start, Qparagraph_separate; |
b7b65b15 | 92 | |
cbb09f04 EZ |
93 | \f |
94 | /*********************************************************************** | |
95 | Utilities | |
96 | ***********************************************************************/ | |
b7b65b15 | 97 | |
6bff6497 EZ |
98 | /* Return the bidi type of a character CH, subject to the current |
99 | directional OVERRIDE. */ | |
55d4c1b2 | 100 | static inline bidi_type_t |
6bff6497 | 101 | bidi_get_type (int ch, bidi_dir_t override) |
b7b65b15 | 102 | { |
6bff6497 EZ |
103 | bidi_type_t default_type; |
104 | ||
e7402cb2 EZ |
105 | if (ch == BIDI_EOB) |
106 | return NEUTRAL_B; | |
e342a24d | 107 | if (ch < 0 || ch > MAX_CHAR) |
1088b922 | 108 | emacs_abort (); |
6bff6497 EZ |
109 | |
110 | default_type = (bidi_type_t) XINT (CHAR_TABLE_REF (bidi_type_table, ch)); | |
bca633fb EZ |
111 | /* Every valid character code, even those that are unassigned by the |
112 | UCD, have some bidi-class property, according to | |
113 | DerivedBidiClass.txt file. Therefore, if we ever get UNKNOWN_BT | |
114 | (= zero) code from CHAR_TABLE_REF, that's a bug. */ | |
115 | if (default_type == UNKNOWN_BT) | |
1088b922 | 116 | emacs_abort (); |
6bff6497 EZ |
117 | |
118 | if (override == NEUTRAL_DIR) | |
119 | return default_type; | |
120 | ||
121 | switch (default_type) | |
122 | { | |
123 | /* Although UAX#9 does not tell, it doesn't make sense to | |
124 | override NEUTRAL_B and LRM/RLM characters. */ | |
125 | case NEUTRAL_B: | |
126 | case LRE: | |
127 | case LRO: | |
128 | case RLE: | |
129 | case RLO: | |
130 | case PDF: | |
131 | return default_type; | |
132 | default: | |
133 | switch (ch) | |
134 | { | |
135 | case LRM_CHAR: | |
136 | case RLM_CHAR: | |
137 | return default_type; | |
138 | default: | |
139 | if (override == L2R) /* X6 */ | |
140 | return STRONG_L; | |
141 | else if (override == R2L) | |
142 | return STRONG_R; | |
143 | else | |
1088b922 | 144 | emacs_abort (); /* can't happen: handled above */ |
6bff6497 EZ |
145 | } |
146 | } | |
b7b65b15 EZ |
147 | } |
148 | ||
f67cdd7f | 149 | static inline void |
2d6e4628 EZ |
150 | bidi_check_type (bidi_type_t type) |
151 | { | |
a54e2c05 | 152 | eassert (UNKNOWN_BT <= type && type <= NEUTRAL_ON); |
2d6e4628 EZ |
153 | } |
154 | ||
b7b65b15 | 155 | /* Given a bidi TYPE of a character, return its category. */ |
55d4c1b2 | 156 | static inline bidi_category_t |
b7b65b15 EZ |
157 | bidi_get_category (bidi_type_t type) |
158 | { | |
159 | switch (type) | |
160 | { | |
161 | case UNKNOWN_BT: | |
162 | return UNKNOWN_BC; | |
163 | case STRONG_L: | |
164 | case STRONG_R: | |
165 | case STRONG_AL: | |
166 | case LRE: | |
167 | case LRO: | |
168 | case RLE: | |
169 | case RLO: | |
170 | return STRONG; | |
171 | case PDF: /* ??? really?? */ | |
172 | case WEAK_EN: | |
173 | case WEAK_ES: | |
174 | case WEAK_ET: | |
175 | case WEAK_AN: | |
176 | case WEAK_CS: | |
177 | case WEAK_NSM: | |
178 | case WEAK_BN: | |
179 | return WEAK; | |
180 | case NEUTRAL_B: | |
181 | case NEUTRAL_S: | |
182 | case NEUTRAL_WS: | |
183 | case NEUTRAL_ON: | |
184 | return NEUTRAL; | |
185 | default: | |
1088b922 | 186 | emacs_abort (); |
b7b65b15 EZ |
187 | } |
188 | } | |
189 | ||
a6e8d97c EZ |
190 | /* Return the mirrored character of C, if it has one. If C has no |
191 | mirrored counterpart, return C. | |
192 | Note: The conditions in UAX#9 clause L4 regarding the surrounding | |
193 | context must be tested by the caller. */ | |
b7b65b15 EZ |
194 | int |
195 | bidi_mirror_char (int c) | |
196 | { | |
cbc4fd20 EZ |
197 | Lisp_Object val; |
198 | ||
199 | if (c == BIDI_EOB) | |
200 | return c; | |
201 | if (c < 0 || c > MAX_CHAR) | |
1088b922 | 202 | emacs_abort (); |
b7b65b15 | 203 | |
cbc4fd20 EZ |
204 | val = CHAR_TABLE_REF (bidi_mirror_table, c); |
205 | if (INTEGERP (val)) | |
b7b65b15 | 206 | { |
da92a98c | 207 | int v; |
9e1a06fc | 208 | |
da92a98c PE |
209 | /* When debugging, check before assigning to V, so that the check |
210 | isn't broken by undefined behavior due to int overflow. */ | |
81899c91 | 211 | eassert (CHAR_VALID_P (XINT (val))); |
9e1a06fc | 212 | |
da92a98c PE |
213 | v = XINT (val); |
214 | ||
9e1a06fc EZ |
215 | /* Minimal test we must do in optimized builds, to prevent weird |
216 | crashes further down the road. */ | |
217 | if (v < 0 || v > MAX_CHAR) | |
1088b922 | 218 | emacs_abort (); |
9e1a06fc EZ |
219 | |
220 | return v; | |
b7b65b15 | 221 | } |
cbc4fd20 | 222 | |
b7b65b15 EZ |
223 | return c; |
224 | } | |
225 | ||
cbb09f04 EZ |
226 | /* Determine the start-of-run (sor) directional type given the two |
227 | embedding levels on either side of the run boundary. Also, update | |
228 | the saved info about previously seen characters, since that info is | |
229 | generally valid for a single level run. */ | |
58b9f433 | 230 | static inline void |
cbb09f04 EZ |
231 | bidi_set_sor_type (struct bidi_it *bidi_it, int level_before, int level_after) |
232 | { | |
512a289d | 233 | int higher_level = (level_before > level_after ? level_before : level_after); |
cbb09f04 EZ |
234 | |
235 | /* The prev_was_pdf gork is required for when we have several PDFs | |
236 | in a row. In that case, we want to compute the sor type for the | |
237 | next level run only once: when we see the first PDF. That's | |
238 | because the sor type depends only on the higher of the two levels | |
239 | that we find on the two sides of the level boundary (see UAX#9, | |
240 | clause X10), and so we don't need to know the final embedding | |
241 | level to which we descend after processing all the PDFs. */ | |
242 | if (!bidi_it->prev_was_pdf || level_before < level_after) | |
243 | /* FIXME: should the default sor direction be user selectable? */ | |
512a289d | 244 | bidi_it->sor = ((higher_level & 1) != 0 ? R2L : L2R); |
cbb09f04 EZ |
245 | if (level_before > level_after) |
246 | bidi_it->prev_was_pdf = 1; | |
247 | ||
248 | bidi_it->prev.type = UNKNOWN_BT; | |
512a289d RS |
249 | bidi_it->last_strong.type = bidi_it->last_strong.type_after_w1 |
250 | = bidi_it->last_strong.orig_type = UNKNOWN_BT; | |
251 | bidi_it->prev_for_neutral.type = (bidi_it->sor == R2L ? STRONG_R : STRONG_L); | |
cbb09f04 EZ |
252 | bidi_it->prev_for_neutral.charpos = bidi_it->charpos; |
253 | bidi_it->prev_for_neutral.bytepos = bidi_it->bytepos; | |
512a289d RS |
254 | bidi_it->next_for_neutral.type = bidi_it->next_for_neutral.type_after_w1 |
255 | = bidi_it->next_for_neutral.orig_type = UNKNOWN_BT; | |
cbb09f04 EZ |
256 | bidi_it->ignore_bn_limit = -1; /* meaning it's unknown */ |
257 | } | |
258 | ||
259 | /* Push the current embedding level and override status; reset the | |
260 | current level to LEVEL and the current override status to OVERRIDE. */ | |
58b9f433 | 261 | static inline void |
cbb09f04 EZ |
262 | bidi_push_embedding_level (struct bidi_it *bidi_it, |
263 | int level, bidi_dir_t override) | |
264 | { | |
265 | bidi_it->stack_idx++; | |
a54e2c05 | 266 | eassert (bidi_it->stack_idx < BIDI_MAXLEVEL); |
cbb09f04 EZ |
267 | bidi_it->level_stack[bidi_it->stack_idx].level = level; |
268 | bidi_it->level_stack[bidi_it->stack_idx].override = override; | |
269 | } | |
270 | ||
271 | /* Pop the embedding level and directional override status from the | |
272 | stack, and return the new level. */ | |
58b9f433 | 273 | static inline int |
cbb09f04 EZ |
274 | bidi_pop_embedding_level (struct bidi_it *bidi_it) |
275 | { | |
276 | /* UAX#9 says to ignore invalid PDFs. */ | |
277 | if (bidi_it->stack_idx > 0) | |
278 | bidi_it->stack_idx--; | |
279 | return bidi_it->level_stack[bidi_it->stack_idx].level; | |
280 | } | |
281 | ||
282 | /* Record in SAVED_INFO the information about the current character. */ | |
58b9f433 | 283 | static inline void |
cbb09f04 EZ |
284 | bidi_remember_char (struct bidi_saved_info *saved_info, |
285 | struct bidi_it *bidi_it) | |
286 | { | |
287 | saved_info->charpos = bidi_it->charpos; | |
288 | saved_info->bytepos = bidi_it->bytepos; | |
289 | saved_info->type = bidi_it->type; | |
290 | bidi_check_type (bidi_it->type); | |
291 | saved_info->type_after_w1 = bidi_it->type_after_w1; | |
292 | bidi_check_type (bidi_it->type_after_w1); | |
293 | saved_info->orig_type = bidi_it->orig_type; | |
294 | bidi_check_type (bidi_it->orig_type); | |
295 | } | |
296 | ||
b7b65b15 EZ |
297 | /* Copy the bidi iterator from FROM to TO. To save cycles, this only |
298 | copies the part of the level stack that is actually in use. */ | |
55d4c1b2 | 299 | static inline void |
b7b65b15 EZ |
300 | bidi_copy_it (struct bidi_it *to, struct bidi_it *from) |
301 | { | |
302 | int i; | |
303 | ||
e69a9370 | 304 | /* Copy everything except the level stack and beyond. */ |
182ce2d2 | 305 | memcpy (to, from, offsetof (struct bidi_it, level_stack[0])); |
b7b65b15 EZ |
306 | |
307 | /* Copy the active part of the level stack. */ | |
308 | to->level_stack[0] = from->level_stack[0]; /* level zero is always in use */ | |
309 | for (i = 1; i <= from->stack_idx; i++) | |
310 | to->level_stack[i] = from->level_stack[i]; | |
311 | } | |
312 | ||
cbb09f04 EZ |
313 | \f |
314 | /*********************************************************************** | |
315 | Caching the bidi iterator states | |
316 | ***********************************************************************/ | |
b7b65b15 | 317 | |
2fe72643 EZ |
318 | #define BIDI_CACHE_CHUNK 200 |
319 | static struct bidi_it *bidi_cache; | |
39e378da | 320 | static ptrdiff_t bidi_cache_size = 0; |
ad6042bb | 321 | enum { elsz = sizeof (struct bidi_it) }; |
39e378da PE |
322 | static ptrdiff_t bidi_cache_idx; /* next unused cache slot */ |
323 | static ptrdiff_t bidi_cache_last_idx; /* slot of last cache hit */ | |
324 | static ptrdiff_t bidi_cache_start = 0; /* start of cache for this | |
87e67904 EZ |
325 | "stack" level */ |
326 | ||
bc18e09d PE |
327 | /* 5-slot stack for saving the start of the previous level of the |
328 | cache. xdisp.c maintains a 5-slot stack for its iterator state, | |
329 | and we need the same size of our stack. */ | |
330 | static ptrdiff_t bidi_cache_start_stack[IT_STACK_SIZE]; | |
331 | static int bidi_cache_sp; | |
332 | ||
333 | /* Size of header used by bidi_shelve_cache. */ | |
334 | enum | |
335 | { | |
512a289d RS |
336 | bidi_shelve_header_size |
337 | = (sizeof (bidi_cache_idx) + sizeof (bidi_cache_start_stack) | |
338 | + sizeof (bidi_cache_sp) + sizeof (bidi_cache_start) | |
339 | + sizeof (bidi_cache_last_idx)) | |
bc18e09d PE |
340 | }; |
341 | ||
87e67904 EZ |
342 | /* Reset the cache state to the empty state. We only reset the part |
343 | of the cache relevant to iteration of the current object. Previous | |
344 | objects, which are pushed on the display iterator's stack, are left | |
345 | intact. This is called when the cached information is no more | |
346 | useful for the current iteration, e.g. when we were reseated to a | |
347 | new position on the same object. */ | |
55d4c1b2 | 348 | static inline void |
b7b65b15 EZ |
349 | bidi_cache_reset (void) |
350 | { | |
87e67904 | 351 | bidi_cache_idx = bidi_cache_start; |
b7b65b15 EZ |
352 | bidi_cache_last_idx = -1; |
353 | } | |
354 | ||
87e67904 EZ |
355 | /* Shrink the cache to its minimal size. Called when we init the bidi |
356 | iterator for reordering a buffer or a string that does not come | |
357 | from display properties, because that means all the previously | |
358 | cached info is of no further use. */ | |
55d4c1b2 | 359 | static inline void |
2fe72643 EZ |
360 | bidi_cache_shrink (void) |
361 | { | |
362 | if (bidi_cache_size > BIDI_CACHE_CHUNK) | |
363 | { | |
38182d90 | 364 | bidi_cache = xrealloc (bidi_cache, BIDI_CACHE_CHUNK * elsz); |
51f30bc5 | 365 | bidi_cache_size = BIDI_CACHE_CHUNK; |
2fe72643 EZ |
366 | } |
367 | bidi_cache_reset (); | |
368 | } | |
369 | ||
55d4c1b2 | 370 | static inline void |
39e378da | 371 | bidi_cache_fetch_state (ptrdiff_t idx, struct bidi_it *bidi_it) |
b7b65b15 EZ |
372 | { |
373 | int current_scan_dir = bidi_it->scan_dir; | |
374 | ||
87e67904 | 375 | if (idx < bidi_cache_start || idx >= bidi_cache_idx) |
1088b922 | 376 | emacs_abort (); |
b7b65b15 EZ |
377 | |
378 | bidi_copy_it (bidi_it, &bidi_cache[idx]); | |
379 | bidi_it->scan_dir = current_scan_dir; | |
380 | bidi_cache_last_idx = idx; | |
381 | } | |
382 | ||
383 | /* Find a cached state with a given CHARPOS and resolved embedding | |
384 | level less or equal to LEVEL. if LEVEL is -1, disregard the | |
385 | resolved levels in cached states. DIR, if non-zero, means search | |
386 | in that direction from the last cache hit. */ | |
39e378da | 387 | static inline ptrdiff_t |
d311d28c | 388 | bidi_cache_search (ptrdiff_t charpos, int level, int dir) |
b7b65b15 | 389 | { |
39e378da | 390 | ptrdiff_t i, i_start; |
b7b65b15 | 391 | |
6eec7596 | 392 | if (bidi_cache_idx > bidi_cache_start) |
b7b65b15 | 393 | { |
6eec7596 EZ |
394 | if (bidi_cache_last_idx == -1) |
395 | bidi_cache_last_idx = bidi_cache_idx - 1; | |
b7b65b15 | 396 | if (charpos < bidi_cache[bidi_cache_last_idx].charpos) |
182ce2d2 EZ |
397 | { |
398 | dir = -1; | |
399 | i_start = bidi_cache_last_idx - 1; | |
400 | } | |
401 | else if (charpos > (bidi_cache[bidi_cache_last_idx].charpos | |
402 | + bidi_cache[bidi_cache_last_idx].nchars - 1)) | |
403 | { | |
404 | dir = 1; | |
405 | i_start = bidi_cache_last_idx + 1; | |
406 | } | |
407 | else if (dir) | |
b7b65b15 EZ |
408 | i_start = bidi_cache_last_idx; |
409 | else | |
410 | { | |
411 | dir = -1; | |
412 | i_start = bidi_cache_idx - 1; | |
413 | } | |
414 | ||
415 | if (dir < 0) | |
416 | { | |
417 | /* Linear search for now; FIXME! */ | |
87e67904 | 418 | for (i = i_start; i >= bidi_cache_start; i--) |
182ce2d2 EZ |
419 | if (bidi_cache[i].charpos <= charpos |
420 | && charpos < bidi_cache[i].charpos + bidi_cache[i].nchars | |
b7b65b15 EZ |
421 | && (level == -1 || bidi_cache[i].resolved_level <= level)) |
422 | return i; | |
423 | } | |
424 | else | |
425 | { | |
426 | for (i = i_start; i < bidi_cache_idx; i++) | |
182ce2d2 EZ |
427 | if (bidi_cache[i].charpos <= charpos |
428 | && charpos < bidi_cache[i].charpos + bidi_cache[i].nchars | |
b7b65b15 EZ |
429 | && (level == -1 || bidi_cache[i].resolved_level <= level)) |
430 | return i; | |
431 | } | |
432 | } | |
433 | ||
434 | return -1; | |
435 | } | |
436 | ||
437 | /* Find a cached state where the resolved level changes to a value | |
438 | that is lower than LEVEL, and return its cache slot index. DIR is | |
439 | the direction to search, starting with the last used cache slot. | |
87e67904 | 440 | If DIR is zero, we search backwards from the last occupied cache |
2cc21167 | 441 | slot. BEFORE means return the index of the slot that |
87e67904 | 442 | is ``before'' the level change in the search direction. That is, |
b7b65b15 EZ |
443 | given the cached levels like this: |
444 | ||
445 | 1122333442211 | |
446 | AB C | |
447 | ||
448 | and assuming we are at the position cached at the slot marked with | |
449 | C, searching backwards (DIR = -1) for LEVEL = 2 will return the | |
450 | index of slot B or A, depending whether BEFORE is, respectively, | |
2cc21167 | 451 | true or false. */ |
39e378da | 452 | static ptrdiff_t |
2cc21167 | 453 | bidi_cache_find_level_change (int level, int dir, bool before) |
b7b65b15 EZ |
454 | { |
455 | if (bidi_cache_idx) | |
456 | { | |
39e378da | 457 | ptrdiff_t i = dir ? bidi_cache_last_idx : bidi_cache_idx - 1; |
b7b65b15 EZ |
458 | int incr = before ? 1 : 0; |
459 | ||
a54e2c05 | 460 | eassert (!dir || bidi_cache_last_idx >= 0); |
6eec7596 | 461 | |
b7b65b15 EZ |
462 | if (!dir) |
463 | dir = -1; | |
464 | else if (!incr) | |
465 | i += dir; | |
466 | ||
467 | if (dir < 0) | |
468 | { | |
87e67904 | 469 | while (i >= bidi_cache_start + incr) |
b7b65b15 EZ |
470 | { |
471 | if (bidi_cache[i - incr].resolved_level >= 0 | |
472 | && bidi_cache[i - incr].resolved_level < level) | |
473 | return i; | |
474 | i--; | |
475 | } | |
476 | } | |
477 | else | |
478 | { | |
479 | while (i < bidi_cache_idx - incr) | |
480 | { | |
481 | if (bidi_cache[i + incr].resolved_level >= 0 | |
482 | && bidi_cache[i + incr].resolved_level < level) | |
483 | return i; | |
484 | i++; | |
485 | } | |
486 | } | |
487 | } | |
488 | ||
489 | return -1; | |
490 | } | |
491 | ||
58b9f433 | 492 | static inline void |
39e378da | 493 | bidi_cache_ensure_space (ptrdiff_t idx) |
58b9f433 EZ |
494 | { |
495 | /* Enlarge the cache as needed. */ | |
496 | if (idx >= bidi_cache_size) | |
497 | { | |
f0eb61e9 PE |
498 | /* The bidi cache cannot be larger than the largest Lisp string |
499 | or buffer. */ | |
512a289d RS |
500 | ptrdiff_t string_or_buffer_bound |
501 | = max (BUF_BYTES_MAX, STRING_BYTES_BOUND); | |
f0eb61e9 PE |
502 | |
503 | /* Also, it cannot be larger than what C can represent. */ | |
512a289d RS |
504 | ptrdiff_t c_bound |
505 | = (min (PTRDIFF_MAX, SIZE_MAX) - bidi_shelve_header_size) / elsz; | |
f0eb61e9 | 506 | |
512a289d RS |
507 | bidi_cache |
508 | = xpalloc (bidi_cache, &bidi_cache_size, | |
509 | max (BIDI_CACHE_CHUNK, idx - bidi_cache_size + 1), | |
510 | min (string_or_buffer_bound, c_bound), elsz); | |
58b9f433 EZ |
511 | } |
512 | } | |
513 | ||
55d4c1b2 | 514 | static inline void |
2cc21167 | 515 | bidi_cache_iterator_state (struct bidi_it *bidi_it, bool resolved) |
b7b65b15 | 516 | { |
39e378da | 517 | ptrdiff_t idx; |
b7b65b15 EZ |
518 | |
519 | /* We should never cache on backward scans. */ | |
520 | if (bidi_it->scan_dir == -1) | |
1088b922 | 521 | emacs_abort (); |
b7b65b15 EZ |
522 | idx = bidi_cache_search (bidi_it->charpos, -1, 1); |
523 | ||
524 | if (idx < 0) | |
525 | { | |
526 | idx = bidi_cache_idx; | |
58b9f433 | 527 | bidi_cache_ensure_space (idx); |
bd924a5d EZ |
528 | /* Character positions should correspond to cache positions 1:1. |
529 | If we are outside the range of cached positions, the cache is | |
530 | useless and must be reset. */ | |
87e67904 | 531 | if (idx > bidi_cache_start && |
182ce2d2 EZ |
532 | (bidi_it->charpos > (bidi_cache[idx - 1].charpos |
533 | + bidi_cache[idx - 1].nchars) | |
a1344e7d | 534 | || bidi_it->charpos < bidi_cache[bidi_cache_start].charpos)) |
bd924a5d EZ |
535 | { |
536 | bidi_cache_reset (); | |
87e67904 | 537 | idx = bidi_cache_start; |
bd924a5d | 538 | } |
102ebb00 | 539 | if (bidi_it->nchars <= 0) |
1088b922 | 540 | emacs_abort (); |
b7b65b15 EZ |
541 | bidi_copy_it (&bidi_cache[idx], bidi_it); |
542 | if (!resolved) | |
543 | bidi_cache[idx].resolved_level = -1; | |
544 | } | |
545 | else | |
546 | { | |
547 | /* Copy only the members which could have changed, to avoid | |
548 | costly copying of the entire struct. */ | |
549 | bidi_cache[idx].type = bidi_it->type; | |
2d6e4628 | 550 | bidi_check_type (bidi_it->type); |
89d3374a EZ |
551 | bidi_cache[idx].type_after_w1 = bidi_it->type_after_w1; |
552 | bidi_check_type (bidi_it->type_after_w1); | |
b7b65b15 EZ |
553 | if (resolved) |
554 | bidi_cache[idx].resolved_level = bidi_it->resolved_level; | |
555 | else | |
556 | bidi_cache[idx].resolved_level = -1; | |
557 | bidi_cache[idx].invalid_levels = bidi_it->invalid_levels; | |
558 | bidi_cache[idx].invalid_rl_levels = bidi_it->invalid_rl_levels; | |
559 | bidi_cache[idx].next_for_neutral = bidi_it->next_for_neutral; | |
560 | bidi_cache[idx].next_for_ws = bidi_it->next_for_ws; | |
561 | bidi_cache[idx].ignore_bn_limit = bidi_it->ignore_bn_limit; | |
f67cdd7f | 562 | bidi_cache[idx].disp_pos = bidi_it->disp_pos; |
0c95fcf7 | 563 | bidi_cache[idx].disp_prop = bidi_it->disp_prop; |
b7b65b15 EZ |
564 | } |
565 | ||
566 | bidi_cache_last_idx = idx; | |
567 | if (idx >= bidi_cache_idx) | |
568 | bidi_cache_idx = idx + 1; | |
569 | } | |
570 | ||
55d4c1b2 | 571 | static inline bidi_type_t |
d311d28c | 572 | bidi_cache_find (ptrdiff_t charpos, int level, struct bidi_it *bidi_it) |
b7b65b15 | 573 | { |
39e378da | 574 | ptrdiff_t i = bidi_cache_search (charpos, level, bidi_it->scan_dir); |
b7b65b15 | 575 | |
87e67904 | 576 | if (i >= bidi_cache_start) |
b7b65b15 EZ |
577 | { |
578 | bidi_dir_t current_scan_dir = bidi_it->scan_dir; | |
579 | ||
5009f85e | 580 | bidi_copy_it (bidi_it, &bidi_cache[i]); |
b7b65b15 | 581 | bidi_cache_last_idx = i; |
5a5fa834 | 582 | /* Don't let scan direction from the cached state override |
b7b65b15 EZ |
583 | the current scan direction. */ |
584 | bidi_it->scan_dir = current_scan_dir; | |
585 | return bidi_it->type; | |
586 | } | |
587 | ||
588 | return UNKNOWN_BT; | |
589 | } | |
590 | ||
55d4c1b2 | 591 | static inline int |
b7b65b15 EZ |
592 | bidi_peek_at_next_level (struct bidi_it *bidi_it) |
593 | { | |
87e67904 | 594 | if (bidi_cache_idx == bidi_cache_start || bidi_cache_last_idx == -1) |
1088b922 | 595 | emacs_abort (); |
b7b65b15 EZ |
596 | return bidi_cache[bidi_cache_last_idx + bidi_it->scan_dir].resolved_level; |
597 | } | |
598 | ||
cbb09f04 | 599 | \f |
58b9f433 EZ |
600 | /*********************************************************************** |
601 | Pushing and popping the bidi iterator state | |
602 | ***********************************************************************/ | |
58b9f433 EZ |
603 | |
604 | /* Push the bidi iterator state in preparation for reordering a | |
605 | different object, e.g. display string found at certain buffer | |
7e2ad32c EZ |
606 | position. Pushing the bidi iterator boils down to saving its |
607 | entire state on the cache and starting a new cache "stacked" on top | |
608 | of the current cache. */ | |
58b9f433 EZ |
609 | void |
610 | bidi_push_it (struct bidi_it *bidi_it) | |
b7b65b15 | 611 | { |
58b9f433 EZ |
612 | /* Save the current iterator state in its entirety after the last |
613 | used cache slot. */ | |
614 | bidi_cache_ensure_space (bidi_cache_idx); | |
615 | memcpy (&bidi_cache[bidi_cache_idx++], bidi_it, sizeof (struct bidi_it)); | |
be39f003 | 616 | |
58b9f433 | 617 | /* Push the current cache start onto the stack. */ |
a54e2c05 | 618 | eassert (bidi_cache_sp < IT_STACK_SIZE); |
58b9f433 | 619 | bidi_cache_start_stack[bidi_cache_sp++] = bidi_cache_start; |
be39f003 | 620 | |
58b9f433 EZ |
621 | /* Start a new level of cache, and make it empty. */ |
622 | bidi_cache_start = bidi_cache_idx; | |
623 | bidi_cache_last_idx = -1; | |
624 | } | |
625 | ||
626 | /* Restore the iterator state saved by bidi_push_it and return the | |
627 | cache to the corresponding state. */ | |
628 | void | |
629 | bidi_pop_it (struct bidi_it *bidi_it) | |
630 | { | |
631 | if (bidi_cache_start <= 0) | |
1088b922 | 632 | emacs_abort (); |
58b9f433 EZ |
633 | |
634 | /* Reset the next free cache slot index to what it was before the | |
635 | call to bidi_push_it. */ | |
636 | bidi_cache_idx = bidi_cache_start - 1; | |
637 | ||
638 | /* Restore the bidi iterator state saved in the cache. */ | |
639 | memcpy (bidi_it, &bidi_cache[bidi_cache_idx], sizeof (struct bidi_it)); | |
640 | ||
641 | /* Pop the previous cache start from the stack. */ | |
642 | if (bidi_cache_sp <= 0) | |
1088b922 | 643 | emacs_abort (); |
58b9f433 EZ |
644 | bidi_cache_start = bidi_cache_start_stack[--bidi_cache_sp]; |
645 | ||
646 | /* Invalidate the last-used cache slot data. */ | |
647 | bidi_cache_last_idx = -1; | |
648 | } | |
649 | ||
ec7cc85b | 650 | static ptrdiff_t bidi_cache_total_alloc; |
35928349 | 651 | |
ed94e6d7 EZ |
652 | /* Stash away a copy of the cache and its control variables. */ |
653 | void * | |
654 | bidi_shelve_cache (void) | |
655 | { | |
656 | unsigned char *databuf; | |
458bfed3 | 657 | ptrdiff_t alloc; |
ed94e6d7 | 658 | |
35928349 | 659 | /* Empty cache. */ |
ed94e6d7 EZ |
660 | if (bidi_cache_idx == 0) |
661 | return NULL; | |
662 | ||
458bfed3 PE |
663 | alloc = (bidi_shelve_header_size |
664 | + bidi_cache_idx * sizeof (struct bidi_it)); | |
665 | databuf = xmalloc (alloc); | |
666 | bidi_cache_total_alloc += alloc; | |
35928349 | 667 | |
ed94e6d7 EZ |
668 | memcpy (databuf, &bidi_cache_idx, sizeof (bidi_cache_idx)); |
669 | memcpy (databuf + sizeof (bidi_cache_idx), | |
670 | bidi_cache, bidi_cache_idx * sizeof (struct bidi_it)); | |
671 | memcpy (databuf + sizeof (bidi_cache_idx) | |
672 | + bidi_cache_idx * sizeof (struct bidi_it), | |
673 | bidi_cache_start_stack, sizeof (bidi_cache_start_stack)); | |
674 | memcpy (databuf + sizeof (bidi_cache_idx) | |
675 | + bidi_cache_idx * sizeof (struct bidi_it) | |
676 | + sizeof (bidi_cache_start_stack), | |
677 | &bidi_cache_sp, sizeof (bidi_cache_sp)); | |
678 | memcpy (databuf + sizeof (bidi_cache_idx) | |
679 | + bidi_cache_idx * sizeof (struct bidi_it) | |
680 | + sizeof (bidi_cache_start_stack) + sizeof (bidi_cache_sp), | |
681 | &bidi_cache_start, sizeof (bidi_cache_start)); | |
682 | memcpy (databuf + sizeof (bidi_cache_idx) | |
683 | + bidi_cache_idx * sizeof (struct bidi_it) | |
684 | + sizeof (bidi_cache_start_stack) + sizeof (bidi_cache_sp) | |
685 | + sizeof (bidi_cache_start), | |
686 | &bidi_cache_last_idx, sizeof (bidi_cache_last_idx)); | |
687 | ||
688 | return databuf; | |
689 | } | |
690 | ||
d1410150 EZ |
691 | /* Restore the cache state from a copy stashed away by |
692 | bidi_shelve_cache, and free the buffer used to stash that copy. | |
2cc21167 | 693 | JUST_FREE means free the buffer, but don't restore the |
d1410150 EZ |
694 | cache; used when the corresponding iterator is discarded instead of |
695 | being restored. */ | |
ed94e6d7 | 696 | void |
2cc21167 | 697 | bidi_unshelve_cache (void *databuf, bool just_free) |
ed94e6d7 EZ |
698 | { |
699 | unsigned char *p = databuf; | |
700 | ||
701 | if (!p) | |
be39f003 | 702 | { |
d1410150 EZ |
703 | if (!just_free) |
704 | { | |
705 | /* A NULL pointer means an empty cache. */ | |
706 | bidi_cache_start = 0; | |
707 | bidi_cache_sp = 0; | |
708 | bidi_cache_reset (); | |
709 | } | |
be39f003 | 710 | } |
ed94e6d7 EZ |
711 | else |
712 | { | |
35928349 EZ |
713 | if (just_free) |
714 | { | |
715 | ptrdiff_t idx; | |
716 | ||
717 | memcpy (&idx, p, sizeof (bidi_cache_idx)); | |
512a289d RS |
718 | bidi_cache_total_alloc |
719 | -= bidi_shelve_header_size + idx * sizeof (struct bidi_it); | |
35928349 EZ |
720 | } |
721 | else | |
722 | { | |
723 | memcpy (&bidi_cache_idx, p, sizeof (bidi_cache_idx)); | |
724 | bidi_cache_ensure_space (bidi_cache_idx); | |
725 | memcpy (bidi_cache, p + sizeof (bidi_cache_idx), | |
726 | bidi_cache_idx * sizeof (struct bidi_it)); | |
727 | memcpy (bidi_cache_start_stack, | |
728 | p + sizeof (bidi_cache_idx) | |
729 | + bidi_cache_idx * sizeof (struct bidi_it), | |
730 | sizeof (bidi_cache_start_stack)); | |
731 | memcpy (&bidi_cache_sp, | |
732 | p + sizeof (bidi_cache_idx) | |
733 | + bidi_cache_idx * sizeof (struct bidi_it) | |
734 | + sizeof (bidi_cache_start_stack), | |
735 | sizeof (bidi_cache_sp)); | |
736 | memcpy (&bidi_cache_start, | |
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 | memcpy (&bidi_cache_last_idx, | |
742 | p + sizeof (bidi_cache_idx) | |
743 | + bidi_cache_idx * sizeof (struct bidi_it) | |
744 | + sizeof (bidi_cache_start_stack) + sizeof (bidi_cache_sp) | |
745 | + sizeof (bidi_cache_start), | |
746 | sizeof (bidi_cache_last_idx)); | |
512a289d RS |
747 | bidi_cache_total_alloc |
748 | -= (bidi_shelve_header_size | |
749 | + bidi_cache_idx * sizeof (struct bidi_it)); | |
35928349 | 750 | } |
ed94e6d7 EZ |
751 | |
752 | xfree (p); | |
753 | } | |
754 | } | |
b7b65b15 | 755 | |
58b9f433 | 756 | \f |
cbb09f04 EZ |
757 | /*********************************************************************** |
758 | Initialization | |
759 | ***********************************************************************/ | |
760 | static void | |
761 | bidi_initialize (void) | |
b7b65b15 | 762 | { |
474a8465 EZ |
763 | bidi_type_table = uniprop_table (intern ("bidi-class")); |
764 | if (NILP (bidi_type_table)) | |
1088b922 | 765 | emacs_abort (); |
cbb09f04 EZ |
766 | staticpro (&bidi_type_table); |
767 | ||
474a8465 EZ |
768 | bidi_mirror_table = uniprop_table (intern ("mirroring")); |
769 | if (NILP (bidi_mirror_table)) | |
1088b922 | 770 | emacs_abort (); |
cbb09f04 EZ |
771 | staticpro (&bidi_mirror_table); |
772 | ||
cbb09f04 EZ |
773 | Qparagraph_start = intern ("paragraph-start"); |
774 | staticpro (&Qparagraph_start); | |
775 | paragraph_start_re = Fsymbol_value (Qparagraph_start); | |
776 | if (!STRINGP (paragraph_start_re)) | |
777 | paragraph_start_re = build_string ("\f\\|[ \t]*$"); | |
778 | staticpro (¶graph_start_re); | |
779 | Qparagraph_separate = intern ("paragraph-separate"); | |
780 | staticpro (&Qparagraph_separate); | |
781 | paragraph_separate_re = Fsymbol_value (Qparagraph_separate); | |
782 | if (!STRINGP (paragraph_separate_re)) | |
783 | paragraph_separate_re = build_string ("[ \t\f]*$"); | |
784 | staticpro (¶graph_separate_re); | |
58b9f433 EZ |
785 | |
786 | bidi_cache_sp = 0; | |
ec7cc85b | 787 | bidi_cache_total_alloc = 0; |
58b9f433 | 788 | |
cbb09f04 | 789 | bidi_initialized = 1; |
b7b65b15 EZ |
790 | } |
791 | ||
cbb09f04 EZ |
792 | /* Do whatever UAX#9 clause X8 says should be done at paragraph's |
793 | end. */ | |
55d4c1b2 | 794 | static inline void |
cbb09f04 | 795 | bidi_set_paragraph_end (struct bidi_it *bidi_it) |
b7b65b15 | 796 | { |
cbb09f04 EZ |
797 | bidi_it->invalid_levels = 0; |
798 | bidi_it->invalid_rl_levels = -1; | |
799 | bidi_it->stack_idx = 0; | |
800 | bidi_it->resolved_level = bidi_it->level_stack[0].level; | |
801 | } | |
b7b65b15 | 802 | |
cbb09f04 EZ |
803 | /* Initialize the bidi iterator from buffer/string position CHARPOS. */ |
804 | void | |
2cc21167 | 805 | bidi_init_it (ptrdiff_t charpos, ptrdiff_t bytepos, bool frame_window_p, |
cbb09f04 EZ |
806 | struct bidi_it *bidi_it) |
807 | { | |
808 | if (! bidi_initialized) | |
809 | bidi_initialize (); | |
810 | if (charpos >= 0) | |
811 | bidi_it->charpos = charpos; | |
812 | if (bytepos >= 0) | |
813 | bidi_it->bytepos = bytepos; | |
814 | bidi_it->frame_window_p = frame_window_p; | |
815 | bidi_it->nchars = -1; /* to be computed in bidi_resolve_explicit_1 */ | |
816 | bidi_it->first_elt = 1; | |
817 | bidi_set_paragraph_end (bidi_it); | |
818 | bidi_it->new_paragraph = 1; | |
819 | bidi_it->separator_limit = -1; | |
820 | bidi_it->type = NEUTRAL_B; | |
821 | bidi_it->type_after_w1 = NEUTRAL_B; | |
822 | bidi_it->orig_type = NEUTRAL_B; | |
823 | bidi_it->prev_was_pdf = 0; | |
512a289d RS |
824 | bidi_it->prev.type = bidi_it->prev.type_after_w1 |
825 | = bidi_it->prev.orig_type = UNKNOWN_BT; | |
826 | bidi_it->last_strong.type = bidi_it->last_strong.type_after_w1 | |
827 | = bidi_it->last_strong.orig_type = UNKNOWN_BT; | |
cbb09f04 | 828 | bidi_it->next_for_neutral.charpos = -1; |
512a289d RS |
829 | bidi_it->next_for_neutral.type |
830 | = bidi_it->next_for_neutral.type_after_w1 | |
831 | = bidi_it->next_for_neutral.orig_type = UNKNOWN_BT; | |
cbb09f04 | 832 | bidi_it->prev_for_neutral.charpos = -1; |
512a289d RS |
833 | bidi_it->prev_for_neutral.type |
834 | = bidi_it->prev_for_neutral.type_after_w1 | |
835 | = bidi_it->prev_for_neutral.orig_type = UNKNOWN_BT; | |
cbb09f04 EZ |
836 | bidi_it->sor = L2R; /* FIXME: should it be user-selectable? */ |
837 | bidi_it->disp_pos = -1; /* invalid/unknown */ | |
0c95fcf7 | 838 | bidi_it->disp_prop = 0; |
cbb09f04 EZ |
839 | /* We can only shrink the cache if we are at the bottom level of its |
840 | "stack". */ | |
841 | if (bidi_cache_start == 0) | |
842 | bidi_cache_shrink (); | |
58b9f433 EZ |
843 | else |
844 | bidi_cache_reset (); | |
b7b65b15 EZ |
845 | } |
846 | ||
182ce2d2 | 847 | /* Perform initializations for reordering a new line of bidi text. */ |
6bff6497 | 848 | static void |
be39f003 EZ |
849 | bidi_line_init (struct bidi_it *bidi_it) |
850 | { | |
851 | bidi_it->scan_dir = 1; /* FIXME: do we need to have control on this? */ | |
852 | bidi_it->resolved_level = bidi_it->level_stack[0].level; | |
853 | bidi_it->level_stack[0].override = NEUTRAL_DIR; /* X1 */ | |
854 | bidi_it->invalid_levels = 0; | |
855 | bidi_it->invalid_rl_levels = -1; | |
4787455f EZ |
856 | /* Setting this to zero will force its recomputation the first time |
857 | we need it for W5. */ | |
858 | bidi_it->next_en_pos = 0; | |
7b5d6677 | 859 | bidi_it->next_en_type = UNKNOWN_BT; |
be39f003 | 860 | bidi_it->next_for_ws.type = UNKNOWN_BT; |
b44d9321 | 861 | bidi_set_sor_type (bidi_it, |
512a289d | 862 | (bidi_it->paragraph_dir == R2L ? 1 : 0), |
be39f003 EZ |
863 | bidi_it->level_stack[0].level); /* X10 */ |
864 | ||
865 | bidi_cache_reset (); | |
866 | } | |
867 | ||
cbb09f04 EZ |
868 | \f |
869 | /*********************************************************************** | |
870 | Fetching characters | |
871 | ***********************************************************************/ | |
872 | ||
f3014ef5 EZ |
873 | /* Count bytes in string S between BEG/BEGBYTE and END. BEG and END |
874 | are zero-based character positions in S, BEGBYTE is byte position | |
2cc21167 | 875 | corresponding to BEG. UNIBYTE means S is a unibyte string. */ |
d311d28c PE |
876 | static inline ptrdiff_t |
877 | bidi_count_bytes (const unsigned char *s, const ptrdiff_t beg, | |
2cc21167 | 878 | const ptrdiff_t begbyte, const ptrdiff_t end, bool unibyte) |
87e67904 | 879 | { |
d311d28c | 880 | ptrdiff_t pos = beg; |
87e67904 EZ |
881 | const unsigned char *p = s + begbyte, *start = p; |
882 | ||
f3014ef5 EZ |
883 | if (unibyte) |
884 | p = s + end; | |
885 | else | |
87e67904 | 886 | { |
f3014ef5 | 887 | if (!CHAR_HEAD_P (*p)) |
1088b922 | 888 | emacs_abort (); |
f3014ef5 EZ |
889 | |
890 | while (pos < end) | |
891 | { | |
892 | p += BYTES_BY_CHAR_HEAD (*p); | |
893 | pos++; | |
894 | } | |
87e67904 EZ |
895 | } |
896 | ||
897 | return p - start; | |
898 | } | |
899 | ||
900 | /* Fetch and returns the character at byte position BYTEPOS. If S is | |
901 | non-NULL, fetch the character from string S; otherwise fetch the | |
2cc21167 | 902 | character from the current buffer. UNIBYTE means S is a |
f3014ef5 | 903 | unibyte string. */ |
87e67904 | 904 | static inline int |
2cc21167 | 905 | bidi_char_at_pos (ptrdiff_t bytepos, const unsigned char *s, bool unibyte) |
87e67904 EZ |
906 | { |
907 | if (s) | |
f3014ef5 EZ |
908 | { |
909 | if (unibyte) | |
910 | return s[bytepos]; | |
911 | else | |
912 | return STRING_CHAR (s + bytepos); | |
913 | } | |
87e67904 EZ |
914 | else |
915 | return FETCH_MULTIBYTE_CHAR (bytepos); | |
916 | } | |
917 | ||
102ebb00 EZ |
918 | /* Fetch and return the character at BYTEPOS/CHARPOS. If that |
919 | character is covered by a display string, treat the entire run of | |
0c95fcf7 EZ |
920 | covered characters as a single character, either u+2029 or u+FFFC, |
921 | and return their combined length in CH_LEN and NCHARS. DISP_POS | |
922 | specifies the character position of the next display string, or -1 | |
b75258b3 EZ |
923 | if not yet computed. When the next character is at or beyond that |
924 | position, the function updates DISP_POS with the position of the | |
2cc21167 | 925 | next display string. *DISP_PROP non-zero means that there's really |
0c95fcf7 | 926 | a display string at DISP_POS, as opposed to when we searched till |
2cc21167 | 927 | DISP_POS without finding one. If *DISP_PROP is 2, it means the |
0c95fcf7 | 928 | display spec is of the form `(space ...)', which is replaced with |
b75258b3 EZ |
929 | u+2029 to handle it as a paragraph separator. STRING->s is the C |
930 | string to iterate, or NULL if iterating over a buffer or a Lisp | |
931 | string; in the latter case, STRING->lstring is the Lisp string. */ | |
fec2107c | 932 | static inline int |
d311d28c | 933 | bidi_fetch_char (ptrdiff_t bytepos, ptrdiff_t charpos, ptrdiff_t *disp_pos, |
0c95fcf7 | 934 | int *disp_prop, struct bidi_string_data *string, |
2cc21167 | 935 | bool frame_window_p, ptrdiff_t *ch_len, ptrdiff_t *nchars) |
182ce2d2 EZ |
936 | { |
937 | int ch; | |
5895d7b9 | 938 | ptrdiff_t endpos |
512a289d | 939 | = (string->s || STRINGP (string->lstring)) ? string->schars : ZV; |
6db161be | 940 | struct text_pos pos; |
e99a9b8b | 941 | int len; |
182ce2d2 | 942 | |
182ce2d2 | 943 | /* If we got past the last known position of display string, compute |
87e67904 EZ |
944 | the position of the next one. That position could be at CHARPOS. */ |
945 | if (charpos < endpos && charpos > *disp_pos) | |
6db161be EZ |
946 | { |
947 | SET_TEXT_POS (pos, charpos, bytepos); | |
55439c61 | 948 | *disp_pos = compute_display_string_pos (&pos, string, frame_window_p, |
0c95fcf7 | 949 | disp_prop); |
6db161be | 950 | } |
102ebb00 EZ |
951 | |
952 | /* Fetch the character at BYTEPOS. */ | |
87e67904 | 953 | if (charpos >= endpos) |
182ce2d2 EZ |
954 | { |
955 | ch = BIDI_EOB; | |
956 | *ch_len = 1; | |
957 | *nchars = 1; | |
87e67904 | 958 | *disp_pos = endpos; |
0c95fcf7 | 959 | *disp_prop = 0; |
182ce2d2 | 960 | } |
0c95fcf7 | 961 | else if (charpos >= *disp_pos && *disp_prop) |
182ce2d2 | 962 | { |
d311d28c | 963 | ptrdiff_t disp_end_pos; |
7b600102 EZ |
964 | |
965 | /* We don't expect to find ourselves in the middle of a display | |
966 | property. Hopefully, it will never be needed. */ | |
967 | if (charpos > *disp_pos) | |
1088b922 | 968 | emacs_abort (); |
0c95fcf7 EZ |
969 | /* Text covered by `display' properties and overlays with |
970 | display properties or display strings is handled as a single | |
971 | character that represents the entire run of characters | |
972 | covered by the display property. */ | |
973 | if (*disp_prop == 2) | |
974 | { | |
975 | /* `(space ...)' display specs are handled as paragraph | |
976 | separators for the purposes of the reordering; see UAX#9 | |
977 | section 3 and clause HL1 in section 4.3 there. */ | |
978 | ch = 0x2029; | |
979 | } | |
980 | else | |
981 | { | |
982 | /* All other display specs are handled as the Unicode Object | |
983 | Replacement Character. */ | |
984 | ch = 0xFFFC; | |
985 | } | |
87e67904 | 986 | disp_end_pos = compute_display_string_end (*disp_pos, string); |
fbcaa2f3 EZ |
987 | if (disp_end_pos < 0) |
988 | { | |
989 | /* Somebody removed the display string from the buffer | |
990 | behind our back. Recover by processing this buffer | |
991 | position as if no display property were present there to | |
992 | begin with. */ | |
993 | *disp_prop = 0; | |
994 | goto normal_char; | |
995 | } | |
7b600102 | 996 | *nchars = disp_end_pos - *disp_pos; |
f3014ef5 | 997 | if (*nchars <= 0) |
1088b922 | 998 | emacs_abort (); |
87e67904 EZ |
999 | if (string->s) |
1000 | *ch_len = bidi_count_bytes (string->s, *disp_pos, bytepos, | |
f3014ef5 | 1001 | disp_end_pos, string->unibyte); |
9f257352 EZ |
1002 | else if (STRINGP (string->lstring)) |
1003 | *ch_len = bidi_count_bytes (SDATA (string->lstring), *disp_pos, | |
f3014ef5 | 1004 | bytepos, disp_end_pos, string->unibyte); |
87e67904 EZ |
1005 | else |
1006 | *ch_len = CHAR_TO_BYTE (disp_end_pos) - bytepos; | |
182ce2d2 | 1007 | } |
182ce2d2 EZ |
1008 | else |
1009 | { | |
fbcaa2f3 | 1010 | normal_char: |
87e67904 EZ |
1011 | if (string->s) |
1012 | { | |
87e67904 | 1013 | |
f3014ef5 EZ |
1014 | if (!string->unibyte) |
1015 | { | |
1016 | ch = STRING_CHAR_AND_LENGTH (string->s + bytepos, len); | |
1017 | *ch_len = len; | |
1018 | } | |
1019 | else | |
1020 | { | |
1021 | ch = UNIBYTE_TO_CHAR (string->s[bytepos]); | |
1022 | *ch_len = 1; | |
1023 | } | |
87e67904 | 1024 | } |
9f257352 EZ |
1025 | else if (STRINGP (string->lstring)) |
1026 | { | |
f3014ef5 EZ |
1027 | if (!string->unibyte) |
1028 | { | |
1029 | ch = STRING_CHAR_AND_LENGTH (SDATA (string->lstring) + bytepos, | |
1030 | len); | |
1031 | *ch_len = len; | |
1032 | } | |
1033 | else | |
1034 | { | |
1035 | ch = UNIBYTE_TO_CHAR (SREF (string->lstring, bytepos)); | |
1036 | *ch_len = 1; | |
1037 | } | |
9f257352 | 1038 | } |
87e67904 EZ |
1039 | else |
1040 | { | |
e99a9b8b EZ |
1041 | ch = STRING_CHAR_AND_LENGTH (BYTE_POS_ADDR (bytepos), len); |
1042 | *ch_len = len; | |
87e67904 | 1043 | } |
182ce2d2 EZ |
1044 | *nchars = 1; |
1045 | } | |
1046 | ||
1047 | /* If we just entered a run of characters covered by a display | |
1048 | string, compute the position of the next display string. */ | |
55439c61 | 1049 | if (charpos + *nchars <= endpos && charpos + *nchars > *disp_pos |
0c95fcf7 | 1050 | && *disp_prop) |
6db161be EZ |
1051 | { |
1052 | SET_TEXT_POS (pos, charpos + *nchars, bytepos + *ch_len); | |
55439c61 | 1053 | *disp_pos = compute_display_string_pos (&pos, string, frame_window_p, |
0c95fcf7 | 1054 | disp_prop); |
6db161be | 1055 | } |
182ce2d2 EZ |
1056 | |
1057 | return ch; | |
1058 | } | |
1059 | ||
cbb09f04 EZ |
1060 | \f |
1061 | /*********************************************************************** | |
1062 | Determining paragraph direction | |
1063 | ***********************************************************************/ | |
1064 | ||
1065 | /* Check if buffer position CHARPOS/BYTEPOS is the end of a paragraph. | |
1066 | Value is the non-negative length of the paragraph separator | |
1067 | following the buffer position, -1 if position is at the beginning | |
1068 | of a new paragraph, or -2 if position is neither at beginning nor | |
1069 | at end of a paragraph. */ | |
d311d28c PE |
1070 | static ptrdiff_t |
1071 | bidi_at_paragraph_end (ptrdiff_t charpos, ptrdiff_t bytepos) | |
cbb09f04 EZ |
1072 | { |
1073 | Lisp_Object sep_re; | |
1074 | Lisp_Object start_re; | |
d311d28c | 1075 | ptrdiff_t val; |
cbb09f04 EZ |
1076 | |
1077 | sep_re = paragraph_separate_re; | |
1078 | start_re = paragraph_start_re; | |
1079 | ||
1080 | val = fast_looking_at (sep_re, charpos, bytepos, ZV, ZV_BYTE, Qnil); | |
1081 | if (val < 0) | |
1082 | { | |
1083 | if (fast_looking_at (start_re, charpos, bytepos, ZV, ZV_BYTE, Qnil) >= 0) | |
1084 | val = -1; | |
1085 | else | |
1086 | val = -2; | |
1087 | } | |
1088 | ||
1089 | return val; | |
1090 | } | |
1091 | ||
1137e8b8 EZ |
1092 | /* On my 2005-vintage machine, searching back for paragraph start |
1093 | takes ~1 ms per line. And bidi_paragraph_init is called 4 times | |
1094 | when user types C-p. The number below limits each call to | |
1095 | bidi_paragraph_init to about 10 ms. */ | |
1096 | #define MAX_PARAGRAPH_SEARCH 7500 | |
1097 | ||
be39f003 | 1098 | /* Find the beginning of this paragraph by looking back in the buffer. |
1137e8b8 EZ |
1099 | Value is the byte position of the paragraph's beginning, or |
1100 | BEGV_BYTE if paragraph_start_re is still not found after looking | |
1101 | back MAX_PARAGRAPH_SEARCH lines in the buffer. */ | |
d311d28c PE |
1102 | static ptrdiff_t |
1103 | bidi_find_paragraph_start (ptrdiff_t pos, ptrdiff_t pos_byte) | |
6bff6497 | 1104 | { |
372b7a95 | 1105 | Lisp_Object re = paragraph_start_re; |
d311d28c | 1106 | ptrdiff_t limit = ZV, limit_byte = ZV_BYTE; |
4c0078d4 | 1107 | ptrdiff_t n = 0; |
6bff6497 | 1108 | |
6bff6497 | 1109 | while (pos_byte > BEGV_BYTE |
1137e8b8 | 1110 | && n++ < MAX_PARAGRAPH_SEARCH |
6bff6497 EZ |
1111 | && fast_looking_at (re, pos, pos_byte, limit, limit_byte, Qnil) < 0) |
1112 | { | |
182ce2d2 EZ |
1113 | /* FIXME: What if the paragraph beginning is covered by a |
1114 | display string? And what if a display string covering some | |
1115 | of the text over which we scan back includes | |
1116 | paragraph_start_re? */ | |
be39f003 EZ |
1117 | pos = find_next_newline_no_quit (pos - 1, -1); |
1118 | pos_byte = CHAR_TO_BYTE (pos); | |
6bff6497 | 1119 | } |
1137e8b8 EZ |
1120 | if (n >= MAX_PARAGRAPH_SEARCH) |
1121 | pos_byte = BEGV_BYTE; | |
be39f003 | 1122 | return pos_byte; |
6bff6497 EZ |
1123 | } |
1124 | ||
ce811ad9 EZ |
1125 | /* On a 3.4 GHz machine, searching forward for a strong directional |
1126 | character in a long paragraph full of weaks or neutrals takes about | |
1127 | 1 ms for each 20K characters. The number below limits each call to | |
1128 | bidi_paragraph_init to less than 10 ms even on slow machines. */ | |
1129 | #define MAX_STRONG_CHAR_SEARCH 100000 | |
1130 | ||
bea4f10c | 1131 | /* Determine the base direction, a.k.a. base embedding level, of the |
b44d9321 EZ |
1132 | paragraph we are about to iterate through. If DIR is either L2R or |
1133 | R2L, just use that. Otherwise, determine the paragraph direction | |
bea4f10c EZ |
1134 | from the first strong directional character of the paragraph. |
1135 | ||
2cc21167 | 1136 | NO_DEFAULT_P means don't default to L2R if the paragraph |
bea4f10c EZ |
1137 | has no strong directional characters and both DIR and |
1138 | bidi_it->paragraph_dir are NEUTRAL_DIR. In that case, search back | |
1139 | in the buffer until a paragraph is found with a strong character, | |
1140 | or until hitting BEGV. In the latter case, fall back to L2R. This | |
1141 | flag is used in current-bidi-paragraph-direction. | |
1142 | ||
1143 | Note that this function gives the paragraph separator the same | |
1144 | direction as the preceding paragraph, even though Emacs generally | |
9858f6c3 | 1145 | views the separator as not belonging to any paragraph. */ |
b7b65b15 | 1146 | void |
2cc21167 | 1147 | bidi_paragraph_init (bidi_dir_t dir, struct bidi_it *bidi_it, bool no_default_p) |
b7b65b15 | 1148 | { |
d311d28c | 1149 | ptrdiff_t bytepos = bidi_it->bytepos; |
2cc21167 | 1150 | bool string_p = bidi_it->string.s || STRINGP (bidi_it->string.lstring); |
d311d28c | 1151 | ptrdiff_t pstartbyte; |
87e67904 EZ |
1152 | /* Note that begbyte is a byte position, while end is a character |
1153 | position. Yes, this is ugly, but we are trying to avoid costly | |
1154 | calls to BYTE_TO_CHAR and its ilk. */ | |
d311d28c PE |
1155 | ptrdiff_t begbyte = string_p ? 0 : BEGV_BYTE; |
1156 | ptrdiff_t end = string_p ? bidi_it->string.schars : ZV; | |
e7402cb2 | 1157 | |
5e65aec0 | 1158 | /* Special case for an empty buffer. */ |
87e67904 | 1159 | if (bytepos == begbyte && bidi_it->charpos == end) |
5e65aec0 | 1160 | dir = L2R; |
9c82e145 | 1161 | /* We should never be called at EOB or before BEGV. */ |
87e67904 | 1162 | else if (bidi_it->charpos >= end || bytepos < begbyte) |
1088b922 | 1163 | emacs_abort (); |
9c82e145 | 1164 | |
be39f003 EZ |
1165 | if (dir == L2R) |
1166 | { | |
1167 | bidi_it->paragraph_dir = L2R; | |
1168 | bidi_it->new_paragraph = 0; | |
1169 | } | |
1170 | else if (dir == R2L) | |
1171 | { | |
1172 | bidi_it->paragraph_dir = R2L; | |
1173 | bidi_it->new_paragraph = 0; | |
1174 | } | |
b7b65b15 EZ |
1175 | else if (dir == NEUTRAL_DIR) /* P2 */ |
1176 | { | |
182ce2d2 | 1177 | int ch; |
d311d28c PE |
1178 | ptrdiff_t ch_len, nchars; |
1179 | ptrdiff_t pos, disp_pos = -1; | |
0c95fcf7 | 1180 | int disp_prop = 0; |
6bff6497 | 1181 | bidi_type_t type; |
9f257352 | 1182 | const unsigned char *s; |
be39f003 | 1183 | |
d20e1419 EZ |
1184 | if (!bidi_initialized) |
1185 | bidi_initialize (); | |
1186 | ||
be39f003 EZ |
1187 | /* If we are inside a paragraph separator, we are just waiting |
1188 | for the separator to be exhausted; use the previous paragraph | |
e5a2fec7 EZ |
1189 | direction. But don't do that if we have been just reseated, |
1190 | because we need to reinitialize below in that case. */ | |
1191 | if (!bidi_it->first_elt | |
1192 | && bidi_it->charpos < bidi_it->separator_limit) | |
be39f003 EZ |
1193 | return; |
1194 | ||
b44d9321 | 1195 | /* If we are on a newline, get past it to where the next |
5e65aec0 EZ |
1196 | paragraph might start. But don't do that at BEGV since then |
1197 | we are potentially in a new paragraph that doesn't yet | |
1198 | exist. */ | |
c143c213 | 1199 | pos = bidi_it->charpos; |
512a289d RS |
1200 | s = (STRINGP (bidi_it->string.lstring) |
1201 | ? SDATA (bidi_it->string.lstring) | |
1202 | : bidi_it->string.s); | |
f3014ef5 EZ |
1203 | if (bytepos > begbyte |
1204 | && bidi_char_at_pos (bytepos, s, bidi_it->string.unibyte) == '\n') | |
be39f003 | 1205 | { |
b44d9321 | 1206 | bytepos++; |
c143c213 | 1207 | pos++; |
be39f003 | 1208 | } |
b44d9321 EZ |
1209 | |
1210 | /* We are either at the beginning of a paragraph or in the | |
1211 | middle of it. Find where this paragraph starts. */ | |
87e67904 EZ |
1212 | if (string_p) |
1213 | { | |
1214 | /* We don't support changes of paragraph direction inside a | |
1215 | string. It is treated as a single paragraph. */ | |
1216 | pstartbyte = 0; | |
1217 | } | |
1218 | else | |
1219 | pstartbyte = bidi_find_paragraph_start (pos, bytepos); | |
be39f003 EZ |
1220 | bidi_it->separator_limit = -1; |
1221 | bidi_it->new_paragraph = 0; | |
bea4f10c | 1222 | |
2cc21167 PE |
1223 | /* The following loop is run more than once only if NO_DEFAULT_P, |
1224 | and only if we are iterating on a buffer. */ | |
bea4f10c | 1225 | do { |
ce811ad9 EZ |
1226 | ptrdiff_t pos1; |
1227 | ||
bea4f10c | 1228 | bytepos = pstartbyte; |
87e67904 EZ |
1229 | if (!string_p) |
1230 | pos = BYTE_TO_CHAR (bytepos); | |
0c95fcf7 | 1231 | ch = bidi_fetch_char (bytepos, pos, &disp_pos, &disp_prop, |
55439c61 | 1232 | &bidi_it->string, |
87e67904 | 1233 | bidi_it->frame_window_p, &ch_len, &nchars); |
bea4f10c EZ |
1234 | type = bidi_get_type (ch, NEUTRAL_DIR); |
1235 | ||
ce811ad9 | 1236 | pos1 = pos; |
182ce2d2 | 1237 | for (pos += nchars, bytepos += ch_len; |
ce811ad9 EZ |
1238 | ((bidi_get_category (type) != STRONG) |
1239 | || (bidi_ignore_explicit_marks_for_paragraph_level | |
1240 | && (type == RLE || type == RLO | |
1241 | || type == LRE || type == LRO))) | |
1242 | /* Stop when searched too far into an abnormally large | |
1243 | paragraph full of weak or neutral characters. */ | |
1244 | && pos - pos1 < MAX_STRONG_CHAR_SEARCH; | |
bea4f10c EZ |
1245 | type = bidi_get_type (ch, NEUTRAL_DIR)) |
1246 | { | |
87e67904 | 1247 | if (pos >= end) |
bea4f10c EZ |
1248 | { |
1249 | /* Pretend there's a paragraph separator at end of | |
87e67904 | 1250 | buffer/string. */ |
bea4f10c EZ |
1251 | type = NEUTRAL_B; |
1252 | break; | |
1253 | } | |
0bb23927 EZ |
1254 | if (!string_p |
1255 | && type == NEUTRAL_B | |
1256 | && bidi_at_paragraph_end (pos, bytepos) >= -1) | |
cf99dcf8 | 1257 | break; |
102ebb00 | 1258 | /* Fetch next character and advance to get past it. */ |
55439c61 | 1259 | ch = bidi_fetch_char (bytepos, pos, &disp_pos, |
0c95fcf7 | 1260 | &disp_prop, &bidi_it->string, |
fc6f18ce | 1261 | bidi_it->frame_window_p, &ch_len, &nchars); |
182ce2d2 EZ |
1262 | pos += nchars; |
1263 | bytepos += ch_len; | |
bea4f10c | 1264 | } |
32413314 EZ |
1265 | if ((type == STRONG_R || type == STRONG_AL) /* P3 */ |
1266 | || (!bidi_ignore_explicit_marks_for_paragraph_level | |
1267 | && (type == RLO || type == RLE))) | |
bea4f10c | 1268 | bidi_it->paragraph_dir = R2L; |
32413314 EZ |
1269 | else if (type == STRONG_L |
1270 | || (!bidi_ignore_explicit_marks_for_paragraph_level | |
1271 | && (type == LRO || type == LRE))) | |
bea4f10c | 1272 | bidi_it->paragraph_dir = L2R; |
87e67904 EZ |
1273 | if (!string_p |
1274 | && no_default_p && bidi_it->paragraph_dir == NEUTRAL_DIR) | |
bea4f10c EZ |
1275 | { |
1276 | /* If this paragraph is at BEGV, default to L2R. */ | |
1277 | if (pstartbyte == BEGV_BYTE) | |
1278 | bidi_it->paragraph_dir = L2R; /* P3 and HL1 */ | |
1279 | else | |
1280 | { | |
d311d28c PE |
1281 | ptrdiff_t prevpbyte = pstartbyte; |
1282 | ptrdiff_t p = BYTE_TO_CHAR (pstartbyte), pbyte = pstartbyte; | |
bea4f10c EZ |
1283 | |
1284 | /* Find the beginning of the previous paragraph, if any. */ | |
1285 | while (pbyte > BEGV_BYTE && prevpbyte >= pstartbyte) | |
1286 | { | |
182ce2d2 EZ |
1287 | /* FXIME: What if p is covered by a display |
1288 | string? See also a FIXME inside | |
1289 | bidi_find_paragraph_start. */ | |
bea4f10c EZ |
1290 | p--; |
1291 | pbyte = CHAR_TO_BYTE (p); | |
1292 | prevpbyte = bidi_find_paragraph_start (p, pbyte); | |
1293 | } | |
1294 | pstartbyte = prevpbyte; | |
1295 | } | |
1296 | } | |
87e67904 EZ |
1297 | } while (!string_p |
1298 | && no_default_p && bidi_it->paragraph_dir == NEUTRAL_DIR); | |
b7b65b15 | 1299 | } |
be39f003 | 1300 | else |
1088b922 | 1301 | emacs_abort (); |
b7b65b15 | 1302 | |
b44d9321 EZ |
1303 | /* Contrary to UAX#9 clause P3, we only default the paragraph |
1304 | direction to L2R if we have no previous usable paragraph | |
bea4f10c | 1305 | direction. This is allowed by the HL1 clause. */ |
d20e1419 | 1306 | if (bidi_it->paragraph_dir != L2R && bidi_it->paragraph_dir != R2L) |
bea4f10c | 1307 | bidi_it->paragraph_dir = L2R; /* P3 and HL1 ``higher-level protocols'' */ |
be39f003 | 1308 | if (bidi_it->paragraph_dir == R2L) |
b44d9321 | 1309 | bidi_it->level_stack[0].level = 1; |
be39f003 | 1310 | else |
b44d9321 | 1311 | bidi_it->level_stack[0].level = 0; |
be39f003 EZ |
1312 | |
1313 | bidi_line_init (bidi_it); | |
b7b65b15 EZ |
1314 | } |
1315 | ||
cbb09f04 EZ |
1316 | \f |
1317 | /*********************************************************************** | |
1318 | Resolving explicit and implicit levels. | |
58b9f433 | 1319 | The rest of this file constitutes the core of the UBA implementation. |
cbb09f04 | 1320 | ***********************************************************************/ |
b7b65b15 | 1321 | |
2cc21167 | 1322 | static inline bool |
182ce2d2 | 1323 | bidi_explicit_dir_char (int ch) |
b7b65b15 | 1324 | { |
182ce2d2 EZ |
1325 | bidi_type_t ch_type; |
1326 | ||
1327 | if (!bidi_initialized) | |
1088b922 | 1328 | emacs_abort (); |
182ce2d2 EZ |
1329 | ch_type = (bidi_type_t) XINT (CHAR_TABLE_REF (bidi_type_table, ch)); |
1330 | return (ch_type == LRE || ch_type == LRO | |
1331 | || ch_type == RLE || ch_type == RLO | |
1332 | || ch_type == PDF); | |
b7b65b15 EZ |
1333 | } |
1334 | ||
1335 | /* A helper function for bidi_resolve_explicit. It advances to the | |
1336 | next character in logical order and determines the new embedding | |
1337 | level and directional override, but does not take into account | |
1338 | empty embeddings. */ | |
1339 | static int | |
1340 | bidi_resolve_explicit_1 (struct bidi_it *bidi_it) | |
1341 | { | |
1342 | int curchar; | |
1343 | bidi_type_t type; | |
1344 | int current_level; | |
1345 | int new_level; | |
1346 | bidi_dir_t override; | |
2cc21167 | 1347 | bool string_p = bidi_it->string.s || STRINGP (bidi_it->string.lstring); |
b7b65b15 | 1348 | |
182ce2d2 EZ |
1349 | /* If reseat()'ed, don't advance, so as to start iteration from the |
1350 | position where we were reseated. bidi_it->bytepos can be less | |
1351 | than BEGV_BYTE after reseat to BEGV. */ | |
87e67904 | 1352 | if (bidi_it->bytepos < (string_p ? 0 : BEGV_BYTE) |
9c82e145 | 1353 | || bidi_it->first_elt) |
e7402cb2 | 1354 | { |
9c82e145 | 1355 | bidi_it->first_elt = 0; |
87e67904 EZ |
1356 | if (string_p) |
1357 | { | |
512a289d RS |
1358 | const unsigned char *p |
1359 | = (STRINGP (bidi_it->string.lstring) | |
1360 | ? SDATA (bidi_it->string.lstring) | |
1361 | : bidi_it->string.s); | |
9f257352 | 1362 | |
87e67904 EZ |
1363 | if (bidi_it->charpos < 0) |
1364 | bidi_it->charpos = 0; | |
f3014ef5 EZ |
1365 | bidi_it->bytepos = bidi_count_bytes (p, 0, 0, bidi_it->charpos, |
1366 | bidi_it->string.unibyte); | |
87e67904 EZ |
1367 | } |
1368 | else | |
1369 | { | |
1370 | if (bidi_it->charpos < BEGV) | |
1371 | bidi_it->charpos = BEGV; | |
1372 | bidi_it->bytepos = CHAR_TO_BYTE (bidi_it->charpos); | |
1373 | } | |
e7402cb2 | 1374 | } |
87e67904 EZ |
1375 | /* Don't move at end of buffer/string. */ |
1376 | else if (bidi_it->charpos < (string_p ? bidi_it->string.schars : ZV)) | |
b7b65b15 | 1377 | { |
182ce2d2 EZ |
1378 | /* Advance to the next character, skipping characters covered by |
1379 | display strings (nchars > 1). */ | |
102ebb00 | 1380 | if (bidi_it->nchars <= 0) |
1088b922 | 1381 | emacs_abort (); |
182ce2d2 | 1382 | bidi_it->charpos += bidi_it->nchars; |
e7402cb2 | 1383 | if (bidi_it->ch_len == 0) |
1088b922 | 1384 | emacs_abort (); |
b7b65b15 EZ |
1385 | bidi_it->bytepos += bidi_it->ch_len; |
1386 | } | |
1387 | ||
1388 | current_level = bidi_it->level_stack[bidi_it->stack_idx].level; /* X1 */ | |
1389 | override = bidi_it->level_stack[bidi_it->stack_idx].override; | |
1390 | new_level = current_level; | |
1391 | ||
87e67904 | 1392 | if (bidi_it->charpos >= (string_p ? bidi_it->string.schars : ZV)) |
e7402cb2 EZ |
1393 | { |
1394 | curchar = BIDI_EOB; | |
1395 | bidi_it->ch_len = 1; | |
182ce2d2 | 1396 | bidi_it->nchars = 1; |
87e67904 | 1397 | bidi_it->disp_pos = (string_p ? bidi_it->string.schars : ZV); |
0c95fcf7 | 1398 | bidi_it->disp_prop = 0; |
e7402cb2 EZ |
1399 | } |
1400 | else | |
1401 | { | |
182ce2d2 EZ |
1402 | /* Fetch the character at BYTEPOS. If it is covered by a |
1403 | display string, treat the entire run of covered characters as | |
1404 | a single character u+FFFC. */ | |
102ebb00 | 1405 | curchar = bidi_fetch_char (bidi_it->bytepos, bidi_it->charpos, |
0c95fcf7 | 1406 | &bidi_it->disp_pos, &bidi_it->disp_prop, |
55439c61 | 1407 | &bidi_it->string, 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. */ | |
58b9f433 | 1845 | static inline 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: | |
1981 | if (!bidi_explicit_dir_char (bidi_it->ch)) | |
1088b922 | 1982 | emacs_abort (); /* can't happen: BNs are skipped */ |
b7b65b15 EZ |
1983 | /* FALLTHROUGH */ |
1984 | case NEUTRAL_B: | |
1985 | /* Marched all the way to the end of this level run. | |
1986 | We need to use the eor type, whose information is | |
1987 | stored by bidi_set_sor_type in the prev_for_neutral | |
1988 | member. */ | |
1989 | if (saved_it.type != WEAK_BN | |
89d3374a | 1990 | || bidi_get_category (bidi_it->prev.type_after_w1) == NEUTRAL) |
4787455f | 1991 | next_type = bidi_it->prev_for_neutral.type; |
b7b65b15 EZ |
1992 | else |
1993 | { | |
1994 | /* This is a BN which does not adjoin neutrals. | |
1995 | Leave its type alone. */ | |
1996 | bidi_copy_it (bidi_it, &saved_it); | |
1997 | return bidi_it->type; | |
1998 | } | |
1999 | break; | |
2000 | default: | |
1088b922 | 2001 | emacs_abort (); |
b7b65b15 EZ |
2002 | } |
2003 | type = bidi_resolve_neutral_1 (saved_it.prev_for_neutral.type, | |
2004 | next_type, current_level); | |
4787455f | 2005 | saved_it.next_for_neutral.type = next_type; |
b7b65b15 | 2006 | saved_it.type = type; |
4787455f | 2007 | bidi_check_type (next_type); |
2d6e4628 | 2008 | bidi_check_type (type); |
b7b65b15 EZ |
2009 | bidi_copy_it (bidi_it, &saved_it); |
2010 | } | |
2011 | } | |
2012 | return type; | |
2013 | } | |
2014 | ||
2015 | /* Given an iterator state in BIDI_IT, advance one character position | |
182ce2d2 EZ |
2016 | in the buffer/string to the next character (in the logical order), |
2017 | resolve the bidi type of that next character, and return that | |
2018 | type. */ | |
fd3998ff | 2019 | static bidi_type_t |
b7b65b15 EZ |
2020 | bidi_type_of_next_char (struct bidi_it *bidi_it) |
2021 | { | |
2022 | bidi_type_t type; | |
2023 | ||
2024 | /* This should always be called during a forward scan. */ | |
2025 | if (bidi_it->scan_dir != 1) | |
1088b922 | 2026 | emacs_abort (); |
b7b65b15 EZ |
2027 | |
2028 | /* Reset the limit until which to ignore BNs if we step out of the | |
2029 | area where we found only empty levels. */ | |
87e67904 | 2030 | if ((bidi_it->ignore_bn_limit > -1 |
b7b65b15 | 2031 | && bidi_it->ignore_bn_limit <= bidi_it->charpos) |
87e67904 | 2032 | || (bidi_it->ignore_bn_limit == -2 |
b7b65b15 | 2033 | && !bidi_explicit_dir_char (bidi_it->ch))) |
87e67904 | 2034 | bidi_it->ignore_bn_limit = -1; |
b7b65b15 EZ |
2035 | |
2036 | type = bidi_resolve_neutral (bidi_it); | |
2037 | ||
2038 | return type; | |
2039 | } | |
2040 | ||
2041 | /* Given an iterator state BIDI_IT, advance one character position in | |
182ce2d2 EZ |
2042 | the buffer/string to the next character (in the current scan |
2043 | direction), resolve the embedding and implicit levels of that next | |
2044 | character, and return the resulting level. */ | |
fd3998ff | 2045 | static int |
b7b65b15 EZ |
2046 | bidi_level_of_next_char (struct bidi_it *bidi_it) |
2047 | { | |
2048 | bidi_type_t type; | |
2049 | int level, prev_level = -1; | |
2050 | struct bidi_saved_info next_for_neutral; | |
d311d28c | 2051 | ptrdiff_t next_char_pos = -2; |
b7b65b15 EZ |
2052 | |
2053 | if (bidi_it->scan_dir == 1) | |
2054 | { | |
5895d7b9 | 2055 | ptrdiff_t eob |
512a289d RS |
2056 | = ((bidi_it->string.s || STRINGP (bidi_it->string.lstring)) |
2057 | ? bidi_it->string.schars : ZV); | |
9f257352 | 2058 | |
b7b65b15 | 2059 | /* There's no sense in trying to advance if we hit end of text. */ |
9f257352 | 2060 | if (bidi_it->charpos >= eob) |
b7b65b15 EZ |
2061 | return bidi_it->resolved_level; |
2062 | ||
2063 | /* Record the info about the previous character. */ | |
89d3374a | 2064 | if (bidi_it->type_after_w1 != WEAK_BN /* W1/Retaining */ |
b7b65b15 EZ |
2065 | && bidi_it->type != WEAK_BN) |
2066 | bidi_remember_char (&bidi_it->prev, bidi_it); | |
89d3374a EZ |
2067 | if (bidi_it->type_after_w1 == STRONG_R |
2068 | || bidi_it->type_after_w1 == STRONG_L | |
2069 | || bidi_it->type_after_w1 == STRONG_AL) | |
b7b65b15 EZ |
2070 | bidi_remember_char (&bidi_it->last_strong, bidi_it); |
2071 | /* FIXME: it sounds like we don't need both prev and | |
2072 | prev_for_neutral members, but I'm leaving them both for now. */ | |
2073 | if (bidi_it->type == STRONG_R || bidi_it->type == STRONG_L | |
2074 | || bidi_it->type == WEAK_EN || bidi_it->type == WEAK_AN) | |
2075 | bidi_remember_char (&bidi_it->prev_for_neutral, bidi_it); | |
2076 | ||
2077 | /* If we overstepped the characters used for resolving neutrals | |
2078 | and whitespace, invalidate their info in the iterator. */ | |
2079 | if (bidi_it->charpos >= bidi_it->next_for_neutral.charpos) | |
2080 | bidi_it->next_for_neutral.type = UNKNOWN_BT; | |
2081 | if (bidi_it->next_en_pos >= 0 | |
2082 | && bidi_it->charpos >= bidi_it->next_en_pos) | |
7b5d6677 EZ |
2083 | { |
2084 | bidi_it->next_en_pos = 0; | |
2085 | bidi_it->next_en_type = UNKNOWN_BT; | |
2086 | } | |
b7b65b15 EZ |
2087 | if (bidi_it->next_for_ws.type != UNKNOWN_BT |
2088 | && bidi_it->charpos >= bidi_it->next_for_ws.charpos) | |
2089 | bidi_it->next_for_ws.type = UNKNOWN_BT; | |
2090 | ||
2091 | /* This must be taken before we fill the iterator with the info | |
2092 | about the next char. If we scan backwards, the iterator | |
2093 | state must be already cached, so there's no need to know the | |
2094 | embedding level of the previous character, since we will be | |
2095 | returning to our caller shortly. */ | |
2096 | prev_level = bidi_it->level_stack[bidi_it->stack_idx].level; | |
2097 | } | |
2098 | next_for_neutral = bidi_it->next_for_neutral; | |
2099 | ||
182ce2d2 EZ |
2100 | /* Perhaps the character we want is already cached. If it is, the |
2101 | call to bidi_cache_find below will return a type other than | |
2102 | UNKNOWN_BT. */ | |
87e67904 | 2103 | if (bidi_cache_idx > bidi_cache_start && !bidi_it->first_elt) |
102ebb00 | 2104 | { |
512a289d RS |
2105 | int bob = ((bidi_it->string.s || STRINGP (bidi_it->string.lstring)) |
2106 | ? 0 : 1); | |
102ebb00 EZ |
2107 | if (bidi_it->scan_dir > 0) |
2108 | { | |
2109 | if (bidi_it->nchars <= 0) | |
1088b922 | 2110 | emacs_abort (); |
102ebb00 EZ |
2111 | next_char_pos = bidi_it->charpos + bidi_it->nchars; |
2112 | } | |
9f257352 | 2113 | else if (bidi_it->charpos >= bob) |
bb269206 EZ |
2114 | /* Implementation note: we allow next_char_pos to be as low as |
2115 | 0 for buffers or -1 for strings, and that is okay because | |
2116 | that's the "position" of the sentinel iterator state we | |
2117 | cached at the beginning of the iteration. */ | |
102ebb00 | 2118 | next_char_pos = bidi_it->charpos - 1; |
578b494e | 2119 | if (next_char_pos >= bob - 1) |
87e67904 EZ |
2120 | type = bidi_cache_find (next_char_pos, -1, bidi_it); |
2121 | else | |
2122 | type = UNKNOWN_BT; | |
102ebb00 | 2123 | } |
182ce2d2 | 2124 | else |
102ebb00 | 2125 | type = UNKNOWN_BT; |
b7b65b15 EZ |
2126 | if (type != UNKNOWN_BT) |
2127 | { | |
2128 | /* Don't lose the information for resolving neutrals! The | |
2129 | cached states could have been cached before their | |
2130 | next_for_neutral member was computed. If we are on our way | |
2131 | forward, we can simply take the info from the previous | |
2132 | state. */ | |
2133 | if (bidi_it->scan_dir == 1 | |
2134 | && bidi_it->next_for_neutral.type == UNKNOWN_BT) | |
2135 | bidi_it->next_for_neutral = next_for_neutral; | |
2136 | ||
2137 | /* If resolved_level is -1, it means this state was cached | |
2138 | before it was completely resolved, so we cannot return | |
2139 | it. */ | |
2140 | if (bidi_it->resolved_level != -1) | |
2141 | return bidi_it->resolved_level; | |
2142 | } | |
2143 | if (bidi_it->scan_dir == -1) | |
2144 | /* If we are going backwards, the iterator state is already cached | |
2145 | from previous scans, and should be fully resolved. */ | |
1088b922 | 2146 | emacs_abort (); |
b7b65b15 EZ |
2147 | |
2148 | if (type == UNKNOWN_BT) | |
2149 | type = bidi_type_of_next_char (bidi_it); | |
2150 | ||
2151 | if (type == NEUTRAL_B) | |
2152 | return bidi_it->resolved_level; | |
2153 | ||
2154 | level = bidi_it->level_stack[bidi_it->stack_idx].level; | |
2155 | if ((bidi_get_category (type) == NEUTRAL /* && type != NEUTRAL_B */) | |
2156 | || (type == WEAK_BN && prev_level == level)) | |
2157 | { | |
2158 | if (bidi_it->next_for_neutral.type == UNKNOWN_BT) | |
1088b922 | 2159 | emacs_abort (); |
b7b65b15 EZ |
2160 | |
2161 | /* If the cached state shows a neutral character, it was not | |
2162 | resolved by bidi_resolve_neutral, so do it now. */ | |
2163 | type = bidi_resolve_neutral_1 (bidi_it->prev_for_neutral.type, | |
2164 | bidi_it->next_for_neutral.type, | |
2165 | level); | |
2166 | } | |
2167 | ||
2168 | if (!(type == STRONG_R | |
2169 | || type == STRONG_L | |
2170 | || type == WEAK_BN | |
2171 | || type == WEAK_EN | |
2172 | || type == WEAK_AN)) | |
1088b922 | 2173 | emacs_abort (); |
b7b65b15 | 2174 | bidi_it->type = type; |
2d6e4628 | 2175 | bidi_check_type (bidi_it->type); |
b7b65b15 EZ |
2176 | |
2177 | /* For L1 below, we need to know, for each WS character, whether | |
0d327994 | 2178 | it belongs to a sequence of WS characters preceding a newline |
b7b65b15 | 2179 | or a TAB or a paragraph separator. */ |
89d3374a | 2180 | if (bidi_it->orig_type == NEUTRAL_WS |
b7b65b15 EZ |
2181 | && bidi_it->next_for_ws.type == UNKNOWN_BT) |
2182 | { | |
2183 | int ch; | |
d311d28c PE |
2184 | ptrdiff_t clen = bidi_it->ch_len; |
2185 | ptrdiff_t bpos = bidi_it->bytepos; | |
2186 | ptrdiff_t cpos = bidi_it->charpos; | |
2187 | ptrdiff_t disp_pos = bidi_it->disp_pos; | |
2188 | ptrdiff_t nc = bidi_it->nchars; | |
87e67904 | 2189 | struct bidi_string_data bs = bidi_it->string; |
b7b65b15 | 2190 | bidi_type_t chtype; |
2cc21167 | 2191 | bool fwp = bidi_it->frame_window_p; |
0c95fcf7 | 2192 | int dpp = bidi_it->disp_prop; |
b7b65b15 | 2193 | |
102ebb00 | 2194 | if (bidi_it->nchars <= 0) |
1088b922 | 2195 | emacs_abort (); |
b7b65b15 | 2196 | do { |
55439c61 EZ |
2197 | ch = bidi_fetch_char (bpos += clen, cpos += nc, &disp_pos, &dpp, &bs, |
2198 | fwp, &clen, &nc); | |
79beb178 | 2199 | if (ch == '\n' || ch == BIDI_EOB) |
b7b65b15 EZ |
2200 | chtype = NEUTRAL_B; |
2201 | else | |
6bff6497 | 2202 | chtype = bidi_get_type (ch, NEUTRAL_DIR); |
b7b65b15 EZ |
2203 | } while (chtype == NEUTRAL_WS || chtype == WEAK_BN |
2204 | || bidi_explicit_dir_char (ch)); /* L1/Retaining */ | |
2205 | bidi_it->next_for_ws.type = chtype; | |
2d6e4628 | 2206 | bidi_check_type (bidi_it->next_for_ws.type); |
b7b65b15 EZ |
2207 | bidi_it->next_for_ws.charpos = cpos; |
2208 | bidi_it->next_for_ws.bytepos = bpos; | |
2209 | } | |
2210 | ||
2211 | /* Resolve implicit levels, with a twist: PDFs get the embedding | |
55622b93 | 2212 | level of the embedding they terminate. See below for the |
b7b65b15 | 2213 | reason. */ |
89d3374a | 2214 | if (bidi_it->orig_type == PDF |
b7b65b15 EZ |
2215 | /* Don't do this if this formatting code didn't change the |
2216 | embedding level due to invalid or empty embeddings. */ | |
2217 | && prev_level != level) | |
2218 | { | |
2219 | /* Don't look in UAX#9 for the reason for this: it's our own | |
2220 | private quirk. The reason is that we want the formatting | |
2221 | codes to be delivered so that they bracket the text of their | |
2222 | embedding. For example, given the text | |
2223 | ||
2224 | {RLO}teST{PDF} | |
2225 | ||
2226 | we want it to be displayed as | |
2227 | ||
0d68907d | 2228 | {PDF}STet{RLO} |
b7b65b15 EZ |
2229 | |
2230 | not as | |
2231 | ||
2232 | STet{RLO}{PDF} | |
2233 | ||
2234 | which will result because we bump up the embedding level as | |
2235 | soon as we see the RLO and pop it as soon as we see the PDF, | |
2236 | so RLO itself has the same embedding level as "teST", and | |
2237 | thus would be normally delivered last, just before the PDF. | |
2238 | The switch below fiddles with the level of PDF so that this | |
2239 | ugly side effect does not happen. | |
2240 | ||
2241 | (This is, of course, only important if the formatting codes | |
e7402cb2 EZ |
2242 | are actually displayed, but Emacs does need to display them |
2243 | if the user wants to.) */ | |
b7b65b15 EZ |
2244 | level = prev_level; |
2245 | } | |
89d3374a EZ |
2246 | else if (bidi_it->orig_type == NEUTRAL_B /* L1 */ |
2247 | || bidi_it->orig_type == NEUTRAL_S | |
e7402cb2 | 2248 | || bidi_it->ch == '\n' || bidi_it->ch == BIDI_EOB |
89d3374a | 2249 | || (bidi_it->orig_type == NEUTRAL_WS |
b7b65b15 EZ |
2250 | && (bidi_it->next_for_ws.type == NEUTRAL_B |
2251 | || bidi_it->next_for_ws.type == NEUTRAL_S))) | |
2252 | level = bidi_it->level_stack[0].level; | |
2253 | else if ((level & 1) == 0) /* I1 */ | |
2254 | { | |
2255 | if (type == STRONG_R) | |
2256 | level++; | |
2257 | else if (type == WEAK_EN || type == WEAK_AN) | |
2258 | level += 2; | |
2259 | } | |
2260 | else /* I2 */ | |
2261 | { | |
2262 | if (type == STRONG_L || type == WEAK_EN || type == WEAK_AN) | |
2263 | level++; | |
2264 | } | |
2265 | ||
2266 | bidi_it->resolved_level = level; | |
2267 | return level; | |
2268 | } | |
2269 | ||
2cc21167 PE |
2270 | /* Move to the other edge of a level given by LEVEL. If END_FLAG, |
2271 | we are at the end of a level, and we need to prepare to | |
b7b65b15 EZ |
2272 | resume the scan of the lower level. |
2273 | ||
2274 | If this level's other edge is cached, we simply jump to it, filling | |
2275 | the iterator structure with the iterator state on the other edge. | |
182ce2d2 EZ |
2276 | Otherwise, we walk the buffer or string until we come back to the |
2277 | same level as LEVEL. | |
b7b65b15 EZ |
2278 | |
2279 | Note: we are not talking here about a ``level run'' in the UAX#9 | |
2280 | sense of the term, but rather about a ``level'' which includes | |
2281 | all the levels higher than it. In other words, given the levels | |
2282 | like this: | |
2283 | ||
2284 | 11111112222222333333334443343222222111111112223322111 | |
2285 | A B C | |
2286 | ||
2287 | and assuming we are at point A scanning left to right, this | |
2288 | function moves to point C, whereas the UAX#9 ``level 2 run'' ends | |
2289 | at point B. */ | |
2290 | static void | |
2cc21167 | 2291 | bidi_find_other_level_edge (struct bidi_it *bidi_it, int level, bool end_flag) |
b7b65b15 EZ |
2292 | { |
2293 | int dir = end_flag ? -bidi_it->scan_dir : bidi_it->scan_dir; | |
39e378da | 2294 | ptrdiff_t idx; |
b7b65b15 EZ |
2295 | |
2296 | /* Try the cache first. */ | |
87e67904 EZ |
2297 | if ((idx = bidi_cache_find_level_change (level, dir, end_flag)) |
2298 | >= bidi_cache_start) | |
b7b65b15 EZ |
2299 | bidi_cache_fetch_state (idx, bidi_it); |
2300 | else | |
2301 | { | |
2302 | int new_level; | |
2303 | ||
1088b922 | 2304 | /* If we are at end of level, its edges must be cached. */ |
b7b65b15 | 2305 | if (end_flag) |
1088b922 | 2306 | emacs_abort (); |
b7b65b15 EZ |
2307 | |
2308 | bidi_cache_iterator_state (bidi_it, 1); | |
2309 | do { | |
2310 | new_level = bidi_level_of_next_char (bidi_it); | |
2311 | bidi_cache_iterator_state (bidi_it, 1); | |
2312 | } while (new_level >= level); | |
2313 | } | |
2314 | } | |
2315 | ||
2316 | void | |
4b292a22 | 2317 | bidi_move_to_visually_next (struct bidi_it *bidi_it) |
b7b65b15 EZ |
2318 | { |
2319 | int old_level, new_level, next_level; | |
9c82e145 | 2320 | struct bidi_it sentinel; |
acb28818 | 2321 | struct gcpro gcpro1; |
b7b65b15 | 2322 | |
87e67904 | 2323 | if (bidi_it->charpos < 0 || bidi_it->bytepos < 0) |
1088b922 | 2324 | emacs_abort (); |
b7b65b15 EZ |
2325 | |
2326 | if (bidi_it->scan_dir == 0) | |
2327 | { | |
2328 | bidi_it->scan_dir = 1; /* default to logical order */ | |
2329 | } | |
2330 | ||
acb28818 | 2331 | /* The code below can call eval, and thus cause GC. If we are |
7e2ad32c | 2332 | iterating a Lisp string, make sure it won't be GCed. */ |
acb28818 EZ |
2333 | if (STRINGP (bidi_it->string.lstring)) |
2334 | GCPRO1 (bidi_it->string.lstring); | |
2335 | ||
be39f003 | 2336 | /* If we just passed a newline, initialize for the next line. */ |
1137e8b8 EZ |
2337 | if (!bidi_it->first_elt |
2338 | && (bidi_it->ch == '\n' || bidi_it->ch == BIDI_EOB)) | |
be39f003 EZ |
2339 | bidi_line_init (bidi_it); |
2340 | ||
6dcfd253 EZ |
2341 | /* Prepare the sentinel iterator state, and cache it. When we bump |
2342 | into it, scanning backwards, we'll know that the last non-base | |
2343 | level is exhausted. */ | |
87e67904 | 2344 | if (bidi_cache_idx == bidi_cache_start) |
9c82e145 EZ |
2345 | { |
2346 | bidi_copy_it (&sentinel, bidi_it); | |
2347 | if (bidi_it->first_elt) | |
2348 | { | |
2349 | sentinel.charpos--; /* cached charpos needs to be monotonic */ | |
2350 | sentinel.bytepos--; | |
2351 | sentinel.ch = '\n'; /* doesn't matter, but why not? */ | |
2352 | sentinel.ch_len = 1; | |
182ce2d2 | 2353 | sentinel.nchars = 1; |
9c82e145 | 2354 | } |
6dcfd253 | 2355 | bidi_cache_iterator_state (&sentinel, 1); |
9c82e145 | 2356 | } |
b7b65b15 EZ |
2357 | |
2358 | old_level = bidi_it->resolved_level; | |
2359 | new_level = bidi_level_of_next_char (bidi_it); | |
b7b65b15 EZ |
2360 | |
2361 | /* Reordering of resolved levels (clause L2) is implemented by | |
2362 | jumping to the other edge of the level and flipping direction of | |
c0546589 | 2363 | scanning the text whenever we find a level change. */ |
b7b65b15 EZ |
2364 | if (new_level != old_level) |
2365 | { | |
2cc21167 | 2366 | bool ascending = new_level > old_level; |
b7b65b15 EZ |
2367 | int level_to_search = ascending ? old_level + 1 : old_level; |
2368 | int incr = ascending ? 1 : -1; | |
2369 | int expected_next_level = old_level + incr; | |
2370 | ||
b7b65b15 EZ |
2371 | /* Jump (or walk) to the other edge of this level. */ |
2372 | bidi_find_other_level_edge (bidi_it, level_to_search, !ascending); | |
2373 | /* Switch scan direction and peek at the next character in the | |
2374 | new direction. */ | |
2375 | bidi_it->scan_dir = -bidi_it->scan_dir; | |
2376 | ||
2377 | /* The following loop handles the case where the resolved level | |
2378 | jumps by more than one. This is typical for numbers inside a | |
2379 | run of text with left-to-right embedding direction, but can | |
2380 | also happen in other situations. In those cases the decision | |
2381 | where to continue after a level change, and in what direction, | |
2382 | is tricky. For example, given a text like below: | |
2383 | ||
2384 | abcdefgh | |
2385 | 11336622 | |
2386 | ||
2387 | (where the numbers below the text show the resolved levels), | |
2388 | the result of reordering according to UAX#9 should be this: | |
2389 | ||
2390 | efdcghba | |
2391 | ||
2392 | This is implemented by the loop below which flips direction | |
2393 | and jumps to the other edge of the level each time it finds | |
2394 | the new level not to be the expected one. The expected level | |
2395 | is always one more or one less than the previous one. */ | |
2396 | next_level = bidi_peek_at_next_level (bidi_it); | |
2397 | while (next_level != expected_next_level) | |
2398 | { | |
2399 | expected_next_level += incr; | |
2400 | level_to_search += incr; | |
2401 | bidi_find_other_level_edge (bidi_it, level_to_search, !ascending); | |
2402 | bidi_it->scan_dir = -bidi_it->scan_dir; | |
2403 | next_level = bidi_peek_at_next_level (bidi_it); | |
2404 | } | |
2405 | ||
2406 | /* Finally, deliver the next character in the new direction. */ | |
2407 | next_level = bidi_level_of_next_char (bidi_it); | |
2408 | } | |
2409 | ||
b44d9321 EZ |
2410 | /* Take note when we have just processed the newline that precedes |
2411 | the end of the paragraph. The next time we are about to be | |
2412 | called, set_iterator_to_next will automatically reinit the | |
2413 | paragraph direction, if needed. We do this at the newline before | |
2414 | the paragraph separator, because the next character might not be | |
2415 | the first character of the next paragraph, due to the bidi | |
c0546589 EZ |
2416 | reordering, whereas we _must_ know the paragraph base direction |
2417 | _before_ we process the paragraph's text, since the base | |
2418 | direction affects the reordering. */ | |
1137e8b8 EZ |
2419 | if (bidi_it->scan_dir == 1 |
2420 | && (bidi_it->ch == '\n' || bidi_it->ch == BIDI_EOB)) | |
be39f003 | 2421 | { |
87e67904 EZ |
2422 | /* The paragraph direction of the entire string, once |
2423 | determined, is in effect for the entire string. Setting the | |
2424 | separator limit to the end of the string prevents | |
2425 | bidi_paragraph_init from being called automatically on this | |
2426 | string. */ | |
9f257352 | 2427 | if (bidi_it->string.s || STRINGP (bidi_it->string.lstring)) |
87e67904 EZ |
2428 | bidi_it->separator_limit = bidi_it->string.schars; |
2429 | else if (bidi_it->bytepos < ZV_BYTE) | |
be39f003 | 2430 | { |
5895d7b9 | 2431 | ptrdiff_t sep_len |
512a289d RS |
2432 | = bidi_at_paragraph_end (bidi_it->charpos + bidi_it->nchars, |
2433 | bidi_it->bytepos + bidi_it->ch_len); | |
87e67904 | 2434 | if (bidi_it->nchars <= 0) |
1088b922 | 2435 | emacs_abort (); |
87e67904 EZ |
2436 | if (sep_len >= 0) |
2437 | { | |
2438 | bidi_it->new_paragraph = 1; | |
2439 | /* Record the buffer position of the last character of the | |
2440 | paragraph separator. */ | |
512a289d RS |
2441 | bidi_it->separator_limit |
2442 | = bidi_it->charpos + bidi_it->nchars + sep_len; | |
87e67904 | 2443 | } |
be39f003 EZ |
2444 | } |
2445 | } | |
6bff6497 | 2446 | |
87e67904 | 2447 | if (bidi_it->scan_dir == 1 && bidi_cache_idx > bidi_cache_start) |
b7b65b15 EZ |
2448 | { |
2449 | /* If we are at paragraph's base embedding level and beyond the | |
2450 | last cached position, the cache's job is done and we can | |
2451 | discard it. */ | |
2452 | if (bidi_it->resolved_level == bidi_it->level_stack[0].level | |
182ce2d2 EZ |
2453 | && bidi_it->charpos > (bidi_cache[bidi_cache_idx - 1].charpos |
2454 | + bidi_cache[bidi_cache_idx - 1].nchars - 1)) | |
b7b65b15 EZ |
2455 | bidi_cache_reset (); |
2456 | /* But as long as we are caching during forward scan, we must | |
2457 | cache each state, or else the cache integrity will be | |
2458 | compromised: it assumes cached states correspond to buffer | |
2459 | positions 1:1. */ | |
2460 | else | |
2461 | bidi_cache_iterator_state (bidi_it, 1); | |
2462 | } | |
acb28818 EZ |
2463 | |
2464 | if (STRINGP (bidi_it->string.lstring)) | |
2465 | UNGCPRO; | |
b7b65b15 EZ |
2466 | } |
2467 | ||
2468 | /* This is meant to be called from within the debugger, whenever you | |
2469 | wish to examine the cache contents. */ | |
e78aecca | 2470 | void bidi_dump_cached_states (void) EXTERNALLY_VISIBLE; |
b7b65b15 EZ |
2471 | void |
2472 | bidi_dump_cached_states (void) | |
2473 | { | |
39e378da | 2474 | ptrdiff_t i; |
b7b65b15 EZ |
2475 | int ndigits = 1; |
2476 | ||
2477 | if (bidi_cache_idx == 0) | |
2478 | { | |
2479 | fprintf (stderr, "The cache is empty.\n"); | |
2480 | return; | |
2481 | } | |
df9733bf | 2482 | fprintf (stderr, "Total of %"pD"d state%s in cache:\n", |
b7b65b15 EZ |
2483 | bidi_cache_idx, bidi_cache_idx == 1 ? "" : "s"); |
2484 | ||
2485 | for (i = bidi_cache[bidi_cache_idx - 1].charpos; i > 0; i /= 10) | |
2486 | ndigits++; | |
2487 | fputs ("ch ", stderr); | |
2488 | for (i = 0; i < bidi_cache_idx; i++) | |
2489 | fprintf (stderr, "%*c", ndigits, bidi_cache[i].ch); | |
2490 | fputs ("\n", stderr); | |
2491 | fputs ("lvl ", stderr); | |
2492 | for (i = 0; i < bidi_cache_idx; i++) | |
2493 | fprintf (stderr, "%*d", ndigits, bidi_cache[i].resolved_level); | |
2494 | fputs ("\n", stderr); | |
2495 | fputs ("pos ", stderr); | |
2496 | for (i = 0; i < bidi_cache_idx; i++) | |
7c85f529 | 2497 | fprintf (stderr, "%*"pD"d", ndigits, bidi_cache[i].charpos); |
b7b65b15 EZ |
2498 | fputs ("\n", stderr); |
2499 | } |