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cbb09f04 | 1 | /* Low-level bidirectional buffer/string-scanning functions for GNU Emacs. |
ba318903 | 2 | Copyright (C) 2000-2001, 2004-2005, 2009-2014 Free Software |
ab422c4d | 3 | Foundation, Inc. |
b7b65b15 EZ |
4 | |
5 | This file is part of GNU Emacs. | |
6 | ||
a8d11bd3 | 7 | GNU Emacs is free software: you can redistribute it and/or modify |
b7b65b15 | 8 | it under the terms of the GNU General Public License as published by |
a8d11bd3 EZ |
9 | the Free Software Foundation, either version 3 of the License, or |
10 | (at your option) any later version. | |
b7b65b15 EZ |
11 | |
12 | GNU Emacs is distributed in the hope that it will be useful, | |
13 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | GNU General Public License for more details. | |
16 | ||
b7b65b15 | 17 | You should have received a copy of the GNU General Public License |
a8d11bd3 | 18 | along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. */ |
b7b65b15 | 19 | |
2d6e4628 EZ |
20 | /* Written by Eli Zaretskii <eliz@gnu.org>. |
21 | ||
22 | A sequential implementation of the Unicode Bidirectional algorithm, | |
cbb09f04 | 23 | (UBA) as per UAX#9, a part of the Unicode Standard. |
b7b65b15 EZ |
24 | |
25 | Unlike the reference and most other implementations, this one is | |
940afb59 EZ |
26 | designed to be called once for every character in the buffer or |
27 | string. | |
b7b65b15 | 28 | |
4b292a22 | 29 | The main entry point is bidi_move_to_visually_next. Each time it |
b7b65b15 EZ |
30 | is called, it finds the next character in the visual order, and |
31 | returns its information in a special structure. The caller is then | |
32 | expected to process this character for display or any other | |
4b292a22 EZ |
33 | purposes, and call bidi_move_to_visually_next for the next |
34 | character. See the comments in bidi_move_to_visually_next for more | |
35 | details about its algorithm that finds the next visual-order | |
b7b65b15 EZ |
36 | character by resolving their levels on the fly. |
37 | ||
95e1afc6 | 38 | Two other entry points are bidi_paragraph_init and |
940afb59 EZ |
39 | bidi_mirror_char. The first determines the base direction of a |
40 | paragraph, while the second returns the mirrored version of its | |
41 | argument character. | |
42 | ||
95e1afc6 EZ |
43 | A few auxiliary entry points are used to initialize the bidi |
44 | iterator for iterating an object (buffer or string), push and pop | |
45 | the bidi iterator state, and save and restore the state of the bidi | |
46 | cache. | |
47 | ||
89d3374a EZ |
48 | If you want to understand the code, you will have to read it |
49 | together with the relevant portions of UAX#9. The comments include | |
50 | references to UAX#9 rules, for that very reason. | |
51 | ||
b7b65b15 EZ |
52 | A note about references to UAX#9 rules: if the reference says |
53 | something like "X9/Retaining", it means that you need to refer to | |
cd1181db | 54 | rule X9 and to its modifications described in the "Implementation |
b7b65b15 EZ |
55 | Notes" section of UAX#9, under "Retaining Format Codes". */ |
56 | ||
b7b65b15 | 57 | #include <config.h> |
b7b65b15 | 58 | #include <stdio.h> |
29e3d8d1 | 59 | |
b7b65b15 | 60 | #include "lisp.h" |
b7b65b15 | 61 | #include "character.h" |
e5560ff7 | 62 | #include "buffer.h" |
b7b65b15 | 63 | #include "dispextern.h" |
e30b79c1 | 64 | #include "region-cache.h" |
b7b65b15 | 65 | |
2cc21167 | 66 | static bool bidi_initialized = 0; |
b7b65b15 | 67 | |
cbc4fd20 | 68 | static Lisp_Object bidi_type_table, bidi_mirror_table; |
b7b65b15 | 69 | |
c521fe29 | 70 | #define BIDI_EOB (-1) |
b7b65b15 | 71 | |
b7b65b15 EZ |
72 | /* Data type for describing the bidirectional character categories. */ |
73 | typedef enum { | |
74 | UNKNOWN_BC, | |
75 | NEUTRAL, | |
76 | WEAK, | |
ad826124 EZ |
77 | STRONG, |
78 | EXPLICIT_FORMATTING | |
b7b65b15 EZ |
79 | } bidi_category_t; |
80 | ||
32413314 EZ |
81 | /* UAX#9 says to search only for L, AL, or R types of characters, and |
82 | ignore RLE, RLO, LRE, and LRO, when determining the base paragraph | |
83 | level. Yudit indeed ignores them. This variable is therefore set | |
2cc21167 PE |
84 | by default to ignore them, but clearing it will take them into |
85 | account. */ | |
86 | extern bool bidi_ignore_explicit_marks_for_paragraph_level EXTERNALLY_VISIBLE; | |
87 | bool bidi_ignore_explicit_marks_for_paragraph_level = 1; | |
b7b65b15 | 88 | |
372b7a95 | 89 | static Lisp_Object paragraph_start_re, paragraph_separate_re; |
6bff6497 | 90 | static Lisp_Object Qparagraph_start, Qparagraph_separate; |
b7b65b15 | 91 | |
cbb09f04 EZ |
92 | \f |
93 | /*********************************************************************** | |
94 | Utilities | |
95 | ***********************************************************************/ | |
b7b65b15 | 96 | |
6bff6497 EZ |
97 | /* Return the bidi type of a character CH, subject to the current |
98 | directional OVERRIDE. */ | |
0a99eee1 | 99 | static bidi_type_t |
6bff6497 | 100 | bidi_get_type (int ch, bidi_dir_t override) |
b7b65b15 | 101 | { |
6bff6497 EZ |
102 | bidi_type_t default_type; |
103 | ||
e7402cb2 EZ |
104 | if (ch == BIDI_EOB) |
105 | return NEUTRAL_B; | |
e342a24d | 106 | if (ch < 0 || ch > MAX_CHAR) |
1088b922 | 107 | emacs_abort (); |
6bff6497 EZ |
108 | |
109 | default_type = (bidi_type_t) XINT (CHAR_TABLE_REF (bidi_type_table, ch)); | |
bca633fb EZ |
110 | /* Every valid character code, even those that are unassigned by the |
111 | UCD, have some bidi-class property, according to | |
112 | DerivedBidiClass.txt file. Therefore, if we ever get UNKNOWN_BT | |
113 | (= zero) code from CHAR_TABLE_REF, that's a bug. */ | |
114 | if (default_type == UNKNOWN_BT) | |
1088b922 | 115 | emacs_abort (); |
6bff6497 | 116 | |
6bff6497 EZ |
117 | switch (default_type) |
118 | { | |
ad826124 | 119 | case WEAK_BN: |
6bff6497 EZ |
120 | case NEUTRAL_B: |
121 | case LRE: | |
122 | case LRO: | |
123 | case RLE: | |
124 | case RLO: | |
125 | case PDF: | |
126 | return default_type; | |
ad826124 EZ |
127 | /* FIXME: The isolate controls are treated as BN until we add |
128 | support for UBA v6.3. */ | |
129 | case LRI: | |
130 | case RLI: | |
131 | case FSI: | |
132 | case PDI: | |
133 | return WEAK_BN; | |
6bff6497 | 134 | default: |
ad826124 EZ |
135 | if (override == L2R) |
136 | return STRONG_L; | |
137 | else if (override == R2L) | |
138 | return STRONG_R; | |
139 | else | |
140 | return default_type; | |
6bff6497 | 141 | } |
b7b65b15 EZ |
142 | } |
143 | ||
0a99eee1 | 144 | static void |
2d6e4628 EZ |
145 | bidi_check_type (bidi_type_t type) |
146 | { | |
a54e2c05 | 147 | eassert (UNKNOWN_BT <= type && type <= NEUTRAL_ON); |
2d6e4628 EZ |
148 | } |
149 | ||
b7b65b15 | 150 | /* Given a bidi TYPE of a character, return its category. */ |
0a99eee1 | 151 | static bidi_category_t |
b7b65b15 EZ |
152 | bidi_get_category (bidi_type_t type) |
153 | { | |
154 | switch (type) | |
155 | { | |
156 | case UNKNOWN_BT: | |
157 | return UNKNOWN_BC; | |
158 | case STRONG_L: | |
159 | case STRONG_R: | |
160 | case STRONG_AL: | |
b7b65b15 | 161 | return STRONG; |
b7b65b15 EZ |
162 | case WEAK_EN: |
163 | case WEAK_ES: | |
164 | case WEAK_ET: | |
165 | case WEAK_AN: | |
166 | case WEAK_CS: | |
167 | case WEAK_NSM: | |
168 | case WEAK_BN: | |
ad826124 EZ |
169 | /* FIXME */ |
170 | case LRI: | |
171 | case RLI: | |
172 | case FSI: | |
173 | case PDI: | |
b7b65b15 EZ |
174 | return WEAK; |
175 | case NEUTRAL_B: | |
176 | case NEUTRAL_S: | |
177 | case NEUTRAL_WS: | |
178 | case NEUTRAL_ON: | |
179 | return NEUTRAL; | |
ad826124 EZ |
180 | case LRE: |
181 | case LRO: | |
182 | case RLE: | |
183 | case RLO: | |
184 | case PDF: | |
185 | #if 0 | |
186 | /* FIXME: This awaits implementation of isolate support. */ | |
187 | case LRI: | |
188 | case RLI: | |
189 | case FSI: | |
190 | case PDI: | |
191 | #endif | |
192 | return EXPLICIT_FORMATTING; | |
b7b65b15 | 193 | default: |
1088b922 | 194 | emacs_abort (); |
b7b65b15 EZ |
195 | } |
196 | } | |
197 | ||
a6e8d97c EZ |
198 | /* Return the mirrored character of C, if it has one. If C has no |
199 | mirrored counterpart, return C. | |
200 | Note: The conditions in UAX#9 clause L4 regarding the surrounding | |
201 | context must be tested by the caller. */ | |
b7b65b15 EZ |
202 | int |
203 | bidi_mirror_char (int c) | |
204 | { | |
cbc4fd20 EZ |
205 | Lisp_Object val; |
206 | ||
207 | if (c == BIDI_EOB) | |
208 | return c; | |
209 | if (c < 0 || c > MAX_CHAR) | |
1088b922 | 210 | emacs_abort (); |
b7b65b15 | 211 | |
cbc4fd20 EZ |
212 | val = CHAR_TABLE_REF (bidi_mirror_table, c); |
213 | if (INTEGERP (val)) | |
b7b65b15 | 214 | { |
da92a98c | 215 | int v; |
9e1a06fc | 216 | |
da92a98c PE |
217 | /* When debugging, check before assigning to V, so that the check |
218 | isn't broken by undefined behavior due to int overflow. */ | |
81899c91 | 219 | eassert (CHAR_VALID_P (XINT (val))); |
9e1a06fc | 220 | |
da92a98c PE |
221 | v = XINT (val); |
222 | ||
9e1a06fc EZ |
223 | /* Minimal test we must do in optimized builds, to prevent weird |
224 | crashes further down the road. */ | |
225 | if (v < 0 || v > MAX_CHAR) | |
1088b922 | 226 | emacs_abort (); |
9e1a06fc EZ |
227 | |
228 | return v; | |
b7b65b15 | 229 | } |
cbc4fd20 | 230 | |
b7b65b15 EZ |
231 | return c; |
232 | } | |
233 | ||
cbb09f04 EZ |
234 | /* Determine the start-of-run (sor) directional type given the two |
235 | embedding levels on either side of the run boundary. Also, update | |
236 | the saved info about previously seen characters, since that info is | |
237 | generally valid for a single level run. */ | |
0a99eee1 | 238 | static void |
cbb09f04 EZ |
239 | bidi_set_sor_type (struct bidi_it *bidi_it, int level_before, int level_after) |
240 | { | |
512a289d | 241 | int higher_level = (level_before > level_after ? level_before : level_after); |
cbb09f04 EZ |
242 | |
243 | /* The prev_was_pdf gork is required for when we have several PDFs | |
244 | in a row. In that case, we want to compute the sor type for the | |
245 | next level run only once: when we see the first PDF. That's | |
246 | because the sor type depends only on the higher of the two levels | |
247 | that we find on the two sides of the level boundary (see UAX#9, | |
248 | clause X10), and so we don't need to know the final embedding | |
249 | level to which we descend after processing all the PDFs. */ | |
250 | if (!bidi_it->prev_was_pdf || level_before < level_after) | |
251 | /* FIXME: should the default sor direction be user selectable? */ | |
512a289d | 252 | bidi_it->sor = ((higher_level & 1) != 0 ? R2L : L2R); |
cbb09f04 EZ |
253 | if (level_before > level_after) |
254 | bidi_it->prev_was_pdf = 1; | |
255 | ||
256 | bidi_it->prev.type = UNKNOWN_BT; | |
512a289d RS |
257 | bidi_it->last_strong.type = bidi_it->last_strong.type_after_w1 |
258 | = bidi_it->last_strong.orig_type = UNKNOWN_BT; | |
259 | bidi_it->prev_for_neutral.type = (bidi_it->sor == R2L ? STRONG_R : STRONG_L); | |
cbb09f04 EZ |
260 | bidi_it->prev_for_neutral.charpos = bidi_it->charpos; |
261 | bidi_it->prev_for_neutral.bytepos = bidi_it->bytepos; | |
512a289d RS |
262 | bidi_it->next_for_neutral.type = bidi_it->next_for_neutral.type_after_w1 |
263 | = bidi_it->next_for_neutral.orig_type = UNKNOWN_BT; | |
cbb09f04 EZ |
264 | bidi_it->ignore_bn_limit = -1; /* meaning it's unknown */ |
265 | } | |
266 | ||
267 | /* Push the current embedding level and override status; reset the | |
268 | current level to LEVEL and the current override status to OVERRIDE. */ | |
0a99eee1 | 269 | static void |
cbb09f04 EZ |
270 | bidi_push_embedding_level (struct bidi_it *bidi_it, |
271 | int level, bidi_dir_t override) | |
272 | { | |
273 | bidi_it->stack_idx++; | |
a54e2c05 | 274 | eassert (bidi_it->stack_idx < BIDI_MAXLEVEL); |
cbb09f04 EZ |
275 | bidi_it->level_stack[bidi_it->stack_idx].level = level; |
276 | bidi_it->level_stack[bidi_it->stack_idx].override = override; | |
277 | } | |
278 | ||
279 | /* Pop the embedding level and directional override status from the | |
280 | stack, and return the new level. */ | |
0a99eee1 | 281 | static int |
cbb09f04 EZ |
282 | bidi_pop_embedding_level (struct bidi_it *bidi_it) |
283 | { | |
284 | /* UAX#9 says to ignore invalid PDFs. */ | |
285 | if (bidi_it->stack_idx > 0) | |
286 | bidi_it->stack_idx--; | |
287 | return bidi_it->level_stack[bidi_it->stack_idx].level; | |
288 | } | |
289 | ||
290 | /* Record in SAVED_INFO the information about the current character. */ | |
0a99eee1 | 291 | static void |
cbb09f04 EZ |
292 | bidi_remember_char (struct bidi_saved_info *saved_info, |
293 | struct bidi_it *bidi_it) | |
294 | { | |
295 | saved_info->charpos = bidi_it->charpos; | |
296 | saved_info->bytepos = bidi_it->bytepos; | |
297 | saved_info->type = bidi_it->type; | |
298 | bidi_check_type (bidi_it->type); | |
299 | saved_info->type_after_w1 = bidi_it->type_after_w1; | |
300 | bidi_check_type (bidi_it->type_after_w1); | |
301 | saved_info->orig_type = bidi_it->orig_type; | |
302 | bidi_check_type (bidi_it->orig_type); | |
303 | } | |
304 | ||
b7b65b15 EZ |
305 | /* Copy the bidi iterator from FROM to TO. To save cycles, this only |
306 | copies the part of the level stack that is actually in use. */ | |
0a99eee1 | 307 | static void |
b7b65b15 EZ |
308 | bidi_copy_it (struct bidi_it *to, struct bidi_it *from) |
309 | { | |
05584c31 PE |
310 | /* Copy everything from the start through the active part of |
311 | the level stack. */ | |
312 | memcpy (to, from, | |
313 | (offsetof (struct bidi_it, level_stack[1]) | |
314 | + from->stack_idx * sizeof from->level_stack[0])); | |
b7b65b15 EZ |
315 | } |
316 | ||
cbb09f04 EZ |
317 | \f |
318 | /*********************************************************************** | |
319 | Caching the bidi iterator states | |
320 | ***********************************************************************/ | |
b7b65b15 | 321 | |
2fe72643 EZ |
322 | #define BIDI_CACHE_CHUNK 200 |
323 | static struct bidi_it *bidi_cache; | |
39e378da | 324 | static ptrdiff_t bidi_cache_size = 0; |
ad6042bb | 325 | enum { elsz = sizeof (struct bidi_it) }; |
39e378da PE |
326 | static ptrdiff_t bidi_cache_idx; /* next unused cache slot */ |
327 | static ptrdiff_t bidi_cache_last_idx; /* slot of last cache hit */ | |
328 | static ptrdiff_t bidi_cache_start = 0; /* start of cache for this | |
87e67904 EZ |
329 | "stack" level */ |
330 | ||
bc18e09d PE |
331 | /* 5-slot stack for saving the start of the previous level of the |
332 | cache. xdisp.c maintains a 5-slot stack for its iterator state, | |
333 | and we need the same size of our stack. */ | |
334 | static ptrdiff_t bidi_cache_start_stack[IT_STACK_SIZE]; | |
335 | static int bidi_cache_sp; | |
336 | ||
337 | /* Size of header used by bidi_shelve_cache. */ | |
338 | enum | |
339 | { | |
512a289d RS |
340 | bidi_shelve_header_size |
341 | = (sizeof (bidi_cache_idx) + sizeof (bidi_cache_start_stack) | |
342 | + sizeof (bidi_cache_sp) + sizeof (bidi_cache_start) | |
343 | + sizeof (bidi_cache_last_idx)) | |
bc18e09d PE |
344 | }; |
345 | ||
87e67904 EZ |
346 | /* Reset the cache state to the empty state. We only reset the part |
347 | of the cache relevant to iteration of the current object. Previous | |
348 | objects, which are pushed on the display iterator's stack, are left | |
349 | intact. This is called when the cached information is no more | |
350 | useful for the current iteration, e.g. when we were reseated to a | |
351 | new position on the same object. */ | |
0a99eee1 | 352 | static void |
b7b65b15 EZ |
353 | bidi_cache_reset (void) |
354 | { | |
87e67904 | 355 | bidi_cache_idx = bidi_cache_start; |
b7b65b15 EZ |
356 | bidi_cache_last_idx = -1; |
357 | } | |
358 | ||
87e67904 EZ |
359 | /* Shrink the cache to its minimal size. Called when we init the bidi |
360 | iterator for reordering a buffer or a string that does not come | |
361 | from display properties, because that means all the previously | |
362 | cached info is of no further use. */ | |
0a99eee1 | 363 | static void |
2fe72643 EZ |
364 | bidi_cache_shrink (void) |
365 | { | |
366 | if (bidi_cache_size > BIDI_CACHE_CHUNK) | |
367 | { | |
38182d90 | 368 | bidi_cache = xrealloc (bidi_cache, BIDI_CACHE_CHUNK * elsz); |
51f30bc5 | 369 | bidi_cache_size = BIDI_CACHE_CHUNK; |
2fe72643 EZ |
370 | } |
371 | bidi_cache_reset (); | |
372 | } | |
373 | ||
0a99eee1 | 374 | static void |
39e378da | 375 | bidi_cache_fetch_state (ptrdiff_t idx, struct bidi_it *bidi_it) |
b7b65b15 EZ |
376 | { |
377 | int current_scan_dir = bidi_it->scan_dir; | |
378 | ||
87e67904 | 379 | if (idx < bidi_cache_start || idx >= bidi_cache_idx) |
1088b922 | 380 | emacs_abort (); |
b7b65b15 EZ |
381 | |
382 | bidi_copy_it (bidi_it, &bidi_cache[idx]); | |
383 | bidi_it->scan_dir = current_scan_dir; | |
384 | bidi_cache_last_idx = idx; | |
385 | } | |
386 | ||
387 | /* Find a cached state with a given CHARPOS and resolved embedding | |
388 | level less or equal to LEVEL. if LEVEL is -1, disregard the | |
389 | resolved levels in cached states. DIR, if non-zero, means search | |
390 | in that direction from the last cache hit. */ | |
0a99eee1 | 391 | static ptrdiff_t |
d311d28c | 392 | bidi_cache_search (ptrdiff_t charpos, int level, int dir) |
b7b65b15 | 393 | { |
39e378da | 394 | ptrdiff_t i, i_start; |
b7b65b15 | 395 | |
6eec7596 | 396 | if (bidi_cache_idx > bidi_cache_start) |
b7b65b15 | 397 | { |
6eec7596 EZ |
398 | if (bidi_cache_last_idx == -1) |
399 | bidi_cache_last_idx = bidi_cache_idx - 1; | |
b7b65b15 | 400 | if (charpos < bidi_cache[bidi_cache_last_idx].charpos) |
182ce2d2 EZ |
401 | { |
402 | dir = -1; | |
403 | i_start = bidi_cache_last_idx - 1; | |
404 | } | |
405 | else if (charpos > (bidi_cache[bidi_cache_last_idx].charpos | |
406 | + bidi_cache[bidi_cache_last_idx].nchars - 1)) | |
407 | { | |
408 | dir = 1; | |
409 | i_start = bidi_cache_last_idx + 1; | |
410 | } | |
411 | else if (dir) | |
b7b65b15 EZ |
412 | i_start = bidi_cache_last_idx; |
413 | else | |
414 | { | |
415 | dir = -1; | |
416 | i_start = bidi_cache_idx - 1; | |
417 | } | |
418 | ||
419 | if (dir < 0) | |
420 | { | |
421 | /* Linear search for now; FIXME! */ | |
87e67904 | 422 | for (i = i_start; i >= bidi_cache_start; i--) |
182ce2d2 EZ |
423 | if (bidi_cache[i].charpos <= charpos |
424 | && charpos < bidi_cache[i].charpos + bidi_cache[i].nchars | |
b7b65b15 EZ |
425 | && (level == -1 || bidi_cache[i].resolved_level <= level)) |
426 | return i; | |
427 | } | |
428 | else | |
429 | { | |
430 | for (i = i_start; i < bidi_cache_idx; i++) | |
182ce2d2 EZ |
431 | if (bidi_cache[i].charpos <= charpos |
432 | && charpos < bidi_cache[i].charpos + bidi_cache[i].nchars | |
b7b65b15 EZ |
433 | && (level == -1 || bidi_cache[i].resolved_level <= level)) |
434 | return i; | |
435 | } | |
436 | } | |
437 | ||
438 | return -1; | |
439 | } | |
440 | ||
441 | /* Find a cached state where the resolved level changes to a value | |
442 | that is lower than LEVEL, and return its cache slot index. DIR is | |
443 | the direction to search, starting with the last used cache slot. | |
87e67904 | 444 | If DIR is zero, we search backwards from the last occupied cache |
2cc21167 | 445 | slot. BEFORE means return the index of the slot that |
87e67904 | 446 | is ``before'' the level change in the search direction. That is, |
b7b65b15 EZ |
447 | given the cached levels like this: |
448 | ||
449 | 1122333442211 | |
450 | AB C | |
451 | ||
452 | and assuming we are at the position cached at the slot marked with | |
453 | C, searching backwards (DIR = -1) for LEVEL = 2 will return the | |
454 | index of slot B or A, depending whether BEFORE is, respectively, | |
2cc21167 | 455 | true or false. */ |
39e378da | 456 | static ptrdiff_t |
2cc21167 | 457 | bidi_cache_find_level_change (int level, int dir, bool before) |
b7b65b15 EZ |
458 | { |
459 | if (bidi_cache_idx) | |
460 | { | |
39e378da | 461 | ptrdiff_t i = dir ? bidi_cache_last_idx : bidi_cache_idx - 1; |
b7b65b15 EZ |
462 | int incr = before ? 1 : 0; |
463 | ||
a54e2c05 | 464 | eassert (!dir || bidi_cache_last_idx >= 0); |
6eec7596 | 465 | |
b7b65b15 EZ |
466 | if (!dir) |
467 | dir = -1; | |
468 | else if (!incr) | |
469 | i += dir; | |
470 | ||
471 | if (dir < 0) | |
472 | { | |
87e67904 | 473 | while (i >= bidi_cache_start + incr) |
b7b65b15 EZ |
474 | { |
475 | if (bidi_cache[i - incr].resolved_level >= 0 | |
476 | && bidi_cache[i - incr].resolved_level < level) | |
477 | return i; | |
478 | i--; | |
479 | } | |
480 | } | |
481 | else | |
482 | { | |
483 | while (i < bidi_cache_idx - incr) | |
484 | { | |
485 | if (bidi_cache[i + incr].resolved_level >= 0 | |
486 | && bidi_cache[i + incr].resolved_level < level) | |
487 | return i; | |
488 | i++; | |
489 | } | |
490 | } | |
491 | } | |
492 | ||
493 | return -1; | |
494 | } | |
495 | ||
0a99eee1 | 496 | static void |
39e378da | 497 | bidi_cache_ensure_space (ptrdiff_t idx) |
58b9f433 EZ |
498 | { |
499 | /* Enlarge the cache as needed. */ | |
500 | if (idx >= bidi_cache_size) | |
501 | { | |
f0eb61e9 PE |
502 | /* The bidi cache cannot be larger than the largest Lisp string |
503 | or buffer. */ | |
512a289d RS |
504 | ptrdiff_t string_or_buffer_bound |
505 | = max (BUF_BYTES_MAX, STRING_BYTES_BOUND); | |
f0eb61e9 PE |
506 | |
507 | /* Also, it cannot be larger than what C can represent. */ | |
512a289d RS |
508 | ptrdiff_t c_bound |
509 | = (min (PTRDIFF_MAX, SIZE_MAX) - bidi_shelve_header_size) / elsz; | |
f0eb61e9 | 510 | |
512a289d RS |
511 | bidi_cache |
512 | = xpalloc (bidi_cache, &bidi_cache_size, | |
513 | max (BIDI_CACHE_CHUNK, idx - bidi_cache_size + 1), | |
514 | min (string_or_buffer_bound, c_bound), elsz); | |
58b9f433 EZ |
515 | } |
516 | } | |
517 | ||
0a99eee1 | 518 | static void |
2cc21167 | 519 | bidi_cache_iterator_state (struct bidi_it *bidi_it, bool resolved) |
b7b65b15 | 520 | { |
39e378da | 521 | ptrdiff_t idx; |
b7b65b15 EZ |
522 | |
523 | /* We should never cache on backward scans. */ | |
524 | if (bidi_it->scan_dir == -1) | |
1088b922 | 525 | emacs_abort (); |
b7b65b15 EZ |
526 | idx = bidi_cache_search (bidi_it->charpos, -1, 1); |
527 | ||
528 | if (idx < 0) | |
529 | { | |
530 | idx = bidi_cache_idx; | |
58b9f433 | 531 | bidi_cache_ensure_space (idx); |
bd924a5d EZ |
532 | /* Character positions should correspond to cache positions 1:1. |
533 | If we are outside the range of cached positions, the cache is | |
534 | useless and must be reset. */ | |
87e67904 | 535 | if (idx > bidi_cache_start && |
182ce2d2 EZ |
536 | (bidi_it->charpos > (bidi_cache[idx - 1].charpos |
537 | + bidi_cache[idx - 1].nchars) | |
a1344e7d | 538 | || bidi_it->charpos < bidi_cache[bidi_cache_start].charpos)) |
bd924a5d EZ |
539 | { |
540 | bidi_cache_reset (); | |
87e67904 | 541 | idx = bidi_cache_start; |
bd924a5d | 542 | } |
102ebb00 | 543 | if (bidi_it->nchars <= 0) |
1088b922 | 544 | emacs_abort (); |
b7b65b15 EZ |
545 | bidi_copy_it (&bidi_cache[idx], bidi_it); |
546 | if (!resolved) | |
547 | bidi_cache[idx].resolved_level = -1; | |
548 | } | |
549 | else | |
550 | { | |
551 | /* Copy only the members which could have changed, to avoid | |
552 | costly copying of the entire struct. */ | |
553 | bidi_cache[idx].type = bidi_it->type; | |
2d6e4628 | 554 | bidi_check_type (bidi_it->type); |
89d3374a EZ |
555 | bidi_cache[idx].type_after_w1 = bidi_it->type_after_w1; |
556 | bidi_check_type (bidi_it->type_after_w1); | |
b7b65b15 EZ |
557 | if (resolved) |
558 | bidi_cache[idx].resolved_level = bidi_it->resolved_level; | |
559 | else | |
560 | bidi_cache[idx].resolved_level = -1; | |
561 | bidi_cache[idx].invalid_levels = bidi_it->invalid_levels; | |
562 | bidi_cache[idx].invalid_rl_levels = bidi_it->invalid_rl_levels; | |
563 | bidi_cache[idx].next_for_neutral = bidi_it->next_for_neutral; | |
564 | bidi_cache[idx].next_for_ws = bidi_it->next_for_ws; | |
565 | bidi_cache[idx].ignore_bn_limit = bidi_it->ignore_bn_limit; | |
f67cdd7f | 566 | bidi_cache[idx].disp_pos = bidi_it->disp_pos; |
0c95fcf7 | 567 | bidi_cache[idx].disp_prop = bidi_it->disp_prop; |
b7b65b15 EZ |
568 | } |
569 | ||
570 | bidi_cache_last_idx = idx; | |
571 | if (idx >= bidi_cache_idx) | |
572 | bidi_cache_idx = idx + 1; | |
573 | } | |
574 | ||
0a99eee1 | 575 | static bidi_type_t |
d311d28c | 576 | bidi_cache_find (ptrdiff_t charpos, int level, struct bidi_it *bidi_it) |
b7b65b15 | 577 | { |
39e378da | 578 | ptrdiff_t i = bidi_cache_search (charpos, level, bidi_it->scan_dir); |
b7b65b15 | 579 | |
87e67904 | 580 | if (i >= bidi_cache_start) |
b7b65b15 EZ |
581 | { |
582 | bidi_dir_t current_scan_dir = bidi_it->scan_dir; | |
583 | ||
5009f85e | 584 | bidi_copy_it (bidi_it, &bidi_cache[i]); |
b7b65b15 | 585 | bidi_cache_last_idx = i; |
5a5fa834 | 586 | /* Don't let scan direction from the cached state override |
b7b65b15 EZ |
587 | the current scan direction. */ |
588 | bidi_it->scan_dir = current_scan_dir; | |
589 | return bidi_it->type; | |
590 | } | |
591 | ||
592 | return UNKNOWN_BT; | |
593 | } | |
594 | ||
0a99eee1 | 595 | static int |
b7b65b15 EZ |
596 | bidi_peek_at_next_level (struct bidi_it *bidi_it) |
597 | { | |
87e67904 | 598 | if (bidi_cache_idx == bidi_cache_start || bidi_cache_last_idx == -1) |
1088b922 | 599 | emacs_abort (); |
b7b65b15 EZ |
600 | return bidi_cache[bidi_cache_last_idx + bidi_it->scan_dir].resolved_level; |
601 | } | |
602 | ||
cbb09f04 | 603 | \f |
58b9f433 EZ |
604 | /*********************************************************************** |
605 | Pushing and popping the bidi iterator state | |
606 | ***********************************************************************/ | |
58b9f433 EZ |
607 | |
608 | /* Push the bidi iterator state in preparation for reordering a | |
609 | different object, e.g. display string found at certain buffer | |
7e2ad32c EZ |
610 | position. Pushing the bidi iterator boils down to saving its |
611 | entire state on the cache and starting a new cache "stacked" on top | |
612 | of the current cache. */ | |
58b9f433 EZ |
613 | void |
614 | bidi_push_it (struct bidi_it *bidi_it) | |
b7b65b15 | 615 | { |
58b9f433 EZ |
616 | /* Save the current iterator state in its entirety after the last |
617 | used cache slot. */ | |
618 | bidi_cache_ensure_space (bidi_cache_idx); | |
ae1d87e2 | 619 | bidi_cache[bidi_cache_idx++] = *bidi_it; |
be39f003 | 620 | |
58b9f433 | 621 | /* Push the current cache start onto the stack. */ |
a54e2c05 | 622 | eassert (bidi_cache_sp < IT_STACK_SIZE); |
58b9f433 | 623 | bidi_cache_start_stack[bidi_cache_sp++] = bidi_cache_start; |
be39f003 | 624 | |
58b9f433 EZ |
625 | /* Start a new level of cache, and make it empty. */ |
626 | bidi_cache_start = bidi_cache_idx; | |
627 | bidi_cache_last_idx = -1; | |
628 | } | |
629 | ||
630 | /* Restore the iterator state saved by bidi_push_it and return the | |
631 | cache to the corresponding state. */ | |
632 | void | |
633 | bidi_pop_it (struct bidi_it *bidi_it) | |
634 | { | |
635 | if (bidi_cache_start <= 0) | |
1088b922 | 636 | emacs_abort (); |
58b9f433 EZ |
637 | |
638 | /* Reset the next free cache slot index to what it was before the | |
639 | call to bidi_push_it. */ | |
640 | bidi_cache_idx = bidi_cache_start - 1; | |
641 | ||
642 | /* Restore the bidi iterator state saved in the cache. */ | |
ae1d87e2 | 643 | *bidi_it = bidi_cache[bidi_cache_idx]; |
58b9f433 EZ |
644 | |
645 | /* Pop the previous cache start from the stack. */ | |
646 | if (bidi_cache_sp <= 0) | |
1088b922 | 647 | emacs_abort (); |
58b9f433 EZ |
648 | bidi_cache_start = bidi_cache_start_stack[--bidi_cache_sp]; |
649 | ||
650 | /* Invalidate the last-used cache slot data. */ | |
651 | bidi_cache_last_idx = -1; | |
652 | } | |
653 | ||
ec7cc85b | 654 | static ptrdiff_t bidi_cache_total_alloc; |
35928349 | 655 | |
ed94e6d7 EZ |
656 | /* Stash away a copy of the cache and its control variables. */ |
657 | void * | |
658 | bidi_shelve_cache (void) | |
659 | { | |
660 | unsigned char *databuf; | |
458bfed3 | 661 | ptrdiff_t alloc; |
ed94e6d7 | 662 | |
35928349 | 663 | /* Empty cache. */ |
ed94e6d7 EZ |
664 | if (bidi_cache_idx == 0) |
665 | return NULL; | |
666 | ||
458bfed3 PE |
667 | alloc = (bidi_shelve_header_size |
668 | + bidi_cache_idx * sizeof (struct bidi_it)); | |
669 | databuf = xmalloc (alloc); | |
670 | bidi_cache_total_alloc += alloc; | |
35928349 | 671 | |
ed94e6d7 EZ |
672 | memcpy (databuf, &bidi_cache_idx, sizeof (bidi_cache_idx)); |
673 | memcpy (databuf + sizeof (bidi_cache_idx), | |
674 | bidi_cache, bidi_cache_idx * sizeof (struct bidi_it)); | |
675 | memcpy (databuf + sizeof (bidi_cache_idx) | |
676 | + bidi_cache_idx * sizeof (struct bidi_it), | |
677 | bidi_cache_start_stack, sizeof (bidi_cache_start_stack)); | |
678 | memcpy (databuf + sizeof (bidi_cache_idx) | |
679 | + bidi_cache_idx * sizeof (struct bidi_it) | |
680 | + sizeof (bidi_cache_start_stack), | |
681 | &bidi_cache_sp, sizeof (bidi_cache_sp)); | |
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 | &bidi_cache_start, sizeof (bidi_cache_start)); | |
686 | memcpy (databuf + sizeof (bidi_cache_idx) | |
687 | + bidi_cache_idx * sizeof (struct bidi_it) | |
688 | + sizeof (bidi_cache_start_stack) + sizeof (bidi_cache_sp) | |
689 | + sizeof (bidi_cache_start), | |
690 | &bidi_cache_last_idx, sizeof (bidi_cache_last_idx)); | |
691 | ||
692 | return databuf; | |
693 | } | |
694 | ||
d1410150 EZ |
695 | /* Restore the cache state from a copy stashed away by |
696 | bidi_shelve_cache, and free the buffer used to stash that copy. | |
2cc21167 | 697 | JUST_FREE means free the buffer, but don't restore the |
d1410150 EZ |
698 | cache; used when the corresponding iterator is discarded instead of |
699 | being restored. */ | |
ed94e6d7 | 700 | void |
2cc21167 | 701 | bidi_unshelve_cache (void *databuf, bool just_free) |
ed94e6d7 EZ |
702 | { |
703 | unsigned char *p = databuf; | |
704 | ||
705 | if (!p) | |
be39f003 | 706 | { |
d1410150 EZ |
707 | if (!just_free) |
708 | { | |
709 | /* A NULL pointer means an empty cache. */ | |
710 | bidi_cache_start = 0; | |
711 | bidi_cache_sp = 0; | |
712 | bidi_cache_reset (); | |
713 | } | |
be39f003 | 714 | } |
ed94e6d7 EZ |
715 | else |
716 | { | |
35928349 EZ |
717 | if (just_free) |
718 | { | |
719 | ptrdiff_t idx; | |
720 | ||
721 | memcpy (&idx, p, sizeof (bidi_cache_idx)); | |
512a289d RS |
722 | bidi_cache_total_alloc |
723 | -= bidi_shelve_header_size + idx * sizeof (struct bidi_it); | |
35928349 EZ |
724 | } |
725 | else | |
726 | { | |
727 | memcpy (&bidi_cache_idx, p, sizeof (bidi_cache_idx)); | |
728 | bidi_cache_ensure_space (bidi_cache_idx); | |
729 | memcpy (bidi_cache, p + sizeof (bidi_cache_idx), | |
730 | bidi_cache_idx * sizeof (struct bidi_it)); | |
731 | memcpy (bidi_cache_start_stack, | |
732 | p + sizeof (bidi_cache_idx) | |
733 | + bidi_cache_idx * sizeof (struct bidi_it), | |
734 | sizeof (bidi_cache_start_stack)); | |
735 | memcpy (&bidi_cache_sp, | |
736 | p + sizeof (bidi_cache_idx) | |
737 | + bidi_cache_idx * sizeof (struct bidi_it) | |
738 | + sizeof (bidi_cache_start_stack), | |
739 | sizeof (bidi_cache_sp)); | |
740 | memcpy (&bidi_cache_start, | |
741 | p + sizeof (bidi_cache_idx) | |
742 | + bidi_cache_idx * sizeof (struct bidi_it) | |
743 | + sizeof (bidi_cache_start_stack) + sizeof (bidi_cache_sp), | |
744 | sizeof (bidi_cache_start)); | |
745 | memcpy (&bidi_cache_last_idx, | |
746 | p + sizeof (bidi_cache_idx) | |
747 | + bidi_cache_idx * sizeof (struct bidi_it) | |
748 | + sizeof (bidi_cache_start_stack) + sizeof (bidi_cache_sp) | |
749 | + sizeof (bidi_cache_start), | |
750 | sizeof (bidi_cache_last_idx)); | |
512a289d RS |
751 | bidi_cache_total_alloc |
752 | -= (bidi_shelve_header_size | |
753 | + bidi_cache_idx * sizeof (struct bidi_it)); | |
35928349 | 754 | } |
ed94e6d7 EZ |
755 | |
756 | xfree (p); | |
757 | } | |
758 | } | |
b7b65b15 | 759 | |
58b9f433 | 760 | \f |
cbb09f04 EZ |
761 | /*********************************************************************** |
762 | Initialization | |
763 | ***********************************************************************/ | |
764 | static void | |
765 | bidi_initialize (void) | |
b7b65b15 | 766 | { |
474a8465 EZ |
767 | bidi_type_table = uniprop_table (intern ("bidi-class")); |
768 | if (NILP (bidi_type_table)) | |
1088b922 | 769 | emacs_abort (); |
cbb09f04 EZ |
770 | staticpro (&bidi_type_table); |
771 | ||
474a8465 EZ |
772 | bidi_mirror_table = uniprop_table (intern ("mirroring")); |
773 | if (NILP (bidi_mirror_table)) | |
1088b922 | 774 | emacs_abort (); |
cbb09f04 EZ |
775 | staticpro (&bidi_mirror_table); |
776 | ||
cbb09f04 EZ |
777 | Qparagraph_start = intern ("paragraph-start"); |
778 | staticpro (&Qparagraph_start); | |
779 | paragraph_start_re = Fsymbol_value (Qparagraph_start); | |
780 | if (!STRINGP (paragraph_start_re)) | |
781 | paragraph_start_re = build_string ("\f\\|[ \t]*$"); | |
782 | staticpro (¶graph_start_re); | |
783 | Qparagraph_separate = intern ("paragraph-separate"); | |
784 | staticpro (&Qparagraph_separate); | |
785 | paragraph_separate_re = Fsymbol_value (Qparagraph_separate); | |
786 | if (!STRINGP (paragraph_separate_re)) | |
787 | paragraph_separate_re = build_string ("[ \t\f]*$"); | |
788 | staticpro (¶graph_separate_re); | |
58b9f433 EZ |
789 | |
790 | bidi_cache_sp = 0; | |
ec7cc85b | 791 | bidi_cache_total_alloc = 0; |
58b9f433 | 792 | |
cbb09f04 | 793 | bidi_initialized = 1; |
b7b65b15 EZ |
794 | } |
795 | ||
cbb09f04 EZ |
796 | /* Do whatever UAX#9 clause X8 says should be done at paragraph's |
797 | end. */ | |
0a99eee1 | 798 | static void |
cbb09f04 | 799 | bidi_set_paragraph_end (struct bidi_it *bidi_it) |
b7b65b15 | 800 | { |
cbb09f04 EZ |
801 | bidi_it->invalid_levels = 0; |
802 | bidi_it->invalid_rl_levels = -1; | |
803 | bidi_it->stack_idx = 0; | |
804 | bidi_it->resolved_level = bidi_it->level_stack[0].level; | |
805 | } | |
b7b65b15 | 806 | |
cbb09f04 EZ |
807 | /* Initialize the bidi iterator from buffer/string position CHARPOS. */ |
808 | void | |
2cc21167 | 809 | bidi_init_it (ptrdiff_t charpos, ptrdiff_t bytepos, bool frame_window_p, |
cbb09f04 EZ |
810 | struct bidi_it *bidi_it) |
811 | { | |
812 | if (! bidi_initialized) | |
813 | bidi_initialize (); | |
814 | if (charpos >= 0) | |
815 | bidi_it->charpos = charpos; | |
816 | if (bytepos >= 0) | |
817 | bidi_it->bytepos = bytepos; | |
818 | bidi_it->frame_window_p = frame_window_p; | |
819 | bidi_it->nchars = -1; /* to be computed in bidi_resolve_explicit_1 */ | |
820 | bidi_it->first_elt = 1; | |
821 | bidi_set_paragraph_end (bidi_it); | |
822 | bidi_it->new_paragraph = 1; | |
823 | bidi_it->separator_limit = -1; | |
824 | bidi_it->type = NEUTRAL_B; | |
825 | bidi_it->type_after_w1 = NEUTRAL_B; | |
826 | bidi_it->orig_type = NEUTRAL_B; | |
827 | bidi_it->prev_was_pdf = 0; | |
512a289d RS |
828 | bidi_it->prev.type = bidi_it->prev.type_after_w1 |
829 | = bidi_it->prev.orig_type = UNKNOWN_BT; | |
830 | bidi_it->last_strong.type = bidi_it->last_strong.type_after_w1 | |
831 | = bidi_it->last_strong.orig_type = UNKNOWN_BT; | |
cbb09f04 | 832 | bidi_it->next_for_neutral.charpos = -1; |
512a289d RS |
833 | bidi_it->next_for_neutral.type |
834 | = bidi_it->next_for_neutral.type_after_w1 | |
835 | = bidi_it->next_for_neutral.orig_type = UNKNOWN_BT; | |
cbb09f04 | 836 | bidi_it->prev_for_neutral.charpos = -1; |
512a289d RS |
837 | bidi_it->prev_for_neutral.type |
838 | = bidi_it->prev_for_neutral.type_after_w1 | |
839 | = bidi_it->prev_for_neutral.orig_type = UNKNOWN_BT; | |
cbb09f04 EZ |
840 | bidi_it->sor = L2R; /* FIXME: should it be user-selectable? */ |
841 | bidi_it->disp_pos = -1; /* invalid/unknown */ | |
0c95fcf7 | 842 | bidi_it->disp_prop = 0; |
cbb09f04 EZ |
843 | /* We can only shrink the cache if we are at the bottom level of its |
844 | "stack". */ | |
845 | if (bidi_cache_start == 0) | |
846 | bidi_cache_shrink (); | |
58b9f433 EZ |
847 | else |
848 | bidi_cache_reset (); | |
b7b65b15 EZ |
849 | } |
850 | ||
182ce2d2 | 851 | /* Perform initializations for reordering a new line of bidi text. */ |
6bff6497 | 852 | static void |
be39f003 EZ |
853 | bidi_line_init (struct bidi_it *bidi_it) |
854 | { | |
855 | bidi_it->scan_dir = 1; /* FIXME: do we need to have control on this? */ | |
856 | bidi_it->resolved_level = bidi_it->level_stack[0].level; | |
857 | bidi_it->level_stack[0].override = NEUTRAL_DIR; /* X1 */ | |
858 | bidi_it->invalid_levels = 0; | |
859 | bidi_it->invalid_rl_levels = -1; | |
4787455f EZ |
860 | /* Setting this to zero will force its recomputation the first time |
861 | we need it for W5. */ | |
862 | bidi_it->next_en_pos = 0; | |
7b5d6677 | 863 | bidi_it->next_en_type = UNKNOWN_BT; |
be39f003 | 864 | bidi_it->next_for_ws.type = UNKNOWN_BT; |
b44d9321 | 865 | bidi_set_sor_type (bidi_it, |
512a289d | 866 | (bidi_it->paragraph_dir == R2L ? 1 : 0), |
be39f003 EZ |
867 | bidi_it->level_stack[0].level); /* X10 */ |
868 | ||
869 | bidi_cache_reset (); | |
870 | } | |
871 | ||
cbb09f04 EZ |
872 | \f |
873 | /*********************************************************************** | |
874 | Fetching characters | |
875 | ***********************************************************************/ | |
876 | ||
f3014ef5 EZ |
877 | /* Count bytes in string S between BEG/BEGBYTE and END. BEG and END |
878 | are zero-based character positions in S, BEGBYTE is byte position | |
2cc21167 | 879 | corresponding to BEG. UNIBYTE means S is a unibyte string. */ |
0a99eee1 | 880 | static ptrdiff_t |
b7ad2f74 PE |
881 | bidi_count_bytes (const unsigned char *s, ptrdiff_t beg, |
882 | ptrdiff_t begbyte, ptrdiff_t end, bool unibyte) | |
87e67904 | 883 | { |
d311d28c | 884 | ptrdiff_t pos = beg; |
87e67904 EZ |
885 | const unsigned char *p = s + begbyte, *start = p; |
886 | ||
f3014ef5 EZ |
887 | if (unibyte) |
888 | p = s + end; | |
889 | else | |
87e67904 | 890 | { |
f3014ef5 | 891 | if (!CHAR_HEAD_P (*p)) |
1088b922 | 892 | emacs_abort (); |
f3014ef5 EZ |
893 | |
894 | while (pos < end) | |
895 | { | |
896 | p += BYTES_BY_CHAR_HEAD (*p); | |
897 | pos++; | |
898 | } | |
87e67904 EZ |
899 | } |
900 | ||
901 | return p - start; | |
902 | } | |
903 | ||
05584c31 | 904 | /* Fetch and return the character at byte position BYTEPOS. If S is |
87e67904 | 905 | non-NULL, fetch the character from string S; otherwise fetch the |
2cc21167 | 906 | character from the current buffer. UNIBYTE means S is a |
f3014ef5 | 907 | unibyte string. */ |
0a99eee1 | 908 | static int |
2cc21167 | 909 | bidi_char_at_pos (ptrdiff_t bytepos, const unsigned char *s, bool unibyte) |
87e67904 EZ |
910 | { |
911 | if (s) | |
f3014ef5 | 912 | { |
05584c31 | 913 | s += bytepos; |
f3014ef5 | 914 | if (unibyte) |
05584c31 | 915 | return *s; |
f3014ef5 | 916 | } |
87e67904 | 917 | else |
05584c31 PE |
918 | s = BYTE_POS_ADDR (bytepos); |
919 | return STRING_CHAR (s); | |
87e67904 EZ |
920 | } |
921 | ||
36075a19 | 922 | /* Fetch and return the character at CHARPOS/BYTEPOS. If that |
102ebb00 | 923 | character is covered by a display string, treat the entire run of |
0c95fcf7 EZ |
924 | covered characters as a single character, either u+2029 or u+FFFC, |
925 | and return their combined length in CH_LEN and NCHARS. DISP_POS | |
926 | specifies the character position of the next display string, or -1 | |
b75258b3 EZ |
927 | if not yet computed. When the next character is at or beyond that |
928 | position, the function updates DISP_POS with the position of the | |
2cc21167 | 929 | next display string. *DISP_PROP non-zero means that there's really |
0c95fcf7 | 930 | a display string at DISP_POS, as opposed to when we searched till |
2cc21167 | 931 | DISP_POS without finding one. If *DISP_PROP is 2, it means the |
0c95fcf7 | 932 | display spec is of the form `(space ...)', which is replaced with |
b75258b3 EZ |
933 | u+2029 to handle it as a paragraph separator. STRING->s is the C |
934 | string to iterate, or NULL if iterating over a buffer or a Lisp | |
935 | string; in the latter case, STRING->lstring is the Lisp string. */ | |
0a99eee1 | 936 | static int |
36075a19 | 937 | bidi_fetch_char (ptrdiff_t charpos, ptrdiff_t bytepos, ptrdiff_t *disp_pos, |
0c95fcf7 | 938 | int *disp_prop, struct bidi_string_data *string, |
5bf97bfc | 939 | struct window *w, |
2cc21167 | 940 | bool frame_window_p, ptrdiff_t *ch_len, ptrdiff_t *nchars) |
182ce2d2 EZ |
941 | { |
942 | int ch; | |
5895d7b9 | 943 | ptrdiff_t endpos |
512a289d | 944 | = (string->s || STRINGP (string->lstring)) ? string->schars : ZV; |
6db161be | 945 | struct text_pos pos; |
e99a9b8b | 946 | int len; |
182ce2d2 | 947 | |
182ce2d2 | 948 | /* If we got past the last known position of display string, compute |
87e67904 EZ |
949 | the position of the next one. That position could be at CHARPOS. */ |
950 | if (charpos < endpos && charpos > *disp_pos) | |
6db161be EZ |
951 | { |
952 | SET_TEXT_POS (pos, charpos, bytepos); | |
5bf97bfc | 953 | *disp_pos = compute_display_string_pos (&pos, string, w, frame_window_p, |
0c95fcf7 | 954 | disp_prop); |
6db161be | 955 | } |
102ebb00 EZ |
956 | |
957 | /* Fetch the character at BYTEPOS. */ | |
87e67904 | 958 | if (charpos >= endpos) |
182ce2d2 EZ |
959 | { |
960 | ch = BIDI_EOB; | |
961 | *ch_len = 1; | |
962 | *nchars = 1; | |
87e67904 | 963 | *disp_pos = endpos; |
0c95fcf7 | 964 | *disp_prop = 0; |
182ce2d2 | 965 | } |
0c95fcf7 | 966 | else if (charpos >= *disp_pos && *disp_prop) |
182ce2d2 | 967 | { |
d311d28c | 968 | ptrdiff_t disp_end_pos; |
7b600102 EZ |
969 | |
970 | /* We don't expect to find ourselves in the middle of a display | |
971 | property. Hopefully, it will never be needed. */ | |
972 | if (charpos > *disp_pos) | |
1088b922 | 973 | emacs_abort (); |
0c95fcf7 EZ |
974 | /* Text covered by `display' properties and overlays with |
975 | display properties or display strings is handled as a single | |
976 | character that represents the entire run of characters | |
977 | covered by the display property. */ | |
978 | if (*disp_prop == 2) | |
979 | { | |
980 | /* `(space ...)' display specs are handled as paragraph | |
981 | separators for the purposes of the reordering; see UAX#9 | |
982 | section 3 and clause HL1 in section 4.3 there. */ | |
983 | ch = 0x2029; | |
984 | } | |
985 | else | |
986 | { | |
987 | /* All other display specs are handled as the Unicode Object | |
988 | Replacement Character. */ | |
989 | ch = 0xFFFC; | |
990 | } | |
87e67904 | 991 | disp_end_pos = compute_display_string_end (*disp_pos, string); |
fbcaa2f3 EZ |
992 | if (disp_end_pos < 0) |
993 | { | |
994 | /* Somebody removed the display string from the buffer | |
995 | behind our back. Recover by processing this buffer | |
996 | position as if no display property were present there to | |
997 | begin with. */ | |
998 | *disp_prop = 0; | |
999 | goto normal_char; | |
1000 | } | |
7b600102 | 1001 | *nchars = disp_end_pos - *disp_pos; |
f3014ef5 | 1002 | if (*nchars <= 0) |
1088b922 | 1003 | emacs_abort (); |
87e67904 EZ |
1004 | if (string->s) |
1005 | *ch_len = bidi_count_bytes (string->s, *disp_pos, bytepos, | |
f3014ef5 | 1006 | disp_end_pos, string->unibyte); |
9f257352 EZ |
1007 | else if (STRINGP (string->lstring)) |
1008 | *ch_len = bidi_count_bytes (SDATA (string->lstring), *disp_pos, | |
f3014ef5 | 1009 | bytepos, disp_end_pos, string->unibyte); |
87e67904 EZ |
1010 | else |
1011 | *ch_len = CHAR_TO_BYTE (disp_end_pos) - bytepos; | |
182ce2d2 | 1012 | } |
182ce2d2 EZ |
1013 | else |
1014 | { | |
fbcaa2f3 | 1015 | normal_char: |
87e67904 EZ |
1016 | if (string->s) |
1017 | { | |
87e67904 | 1018 | |
f3014ef5 EZ |
1019 | if (!string->unibyte) |
1020 | { | |
1021 | ch = STRING_CHAR_AND_LENGTH (string->s + bytepos, len); | |
1022 | *ch_len = len; | |
1023 | } | |
1024 | else | |
1025 | { | |
1026 | ch = UNIBYTE_TO_CHAR (string->s[bytepos]); | |
1027 | *ch_len = 1; | |
1028 | } | |
87e67904 | 1029 | } |
9f257352 EZ |
1030 | else if (STRINGP (string->lstring)) |
1031 | { | |
f3014ef5 EZ |
1032 | if (!string->unibyte) |
1033 | { | |
1034 | ch = STRING_CHAR_AND_LENGTH (SDATA (string->lstring) + bytepos, | |
1035 | len); | |
1036 | *ch_len = len; | |
1037 | } | |
1038 | else | |
1039 | { | |
1040 | ch = UNIBYTE_TO_CHAR (SREF (string->lstring, bytepos)); | |
1041 | *ch_len = 1; | |
1042 | } | |
9f257352 | 1043 | } |
87e67904 EZ |
1044 | else |
1045 | { | |
e99a9b8b EZ |
1046 | ch = STRING_CHAR_AND_LENGTH (BYTE_POS_ADDR (bytepos), len); |
1047 | *ch_len = len; | |
87e67904 | 1048 | } |
182ce2d2 EZ |
1049 | *nchars = 1; |
1050 | } | |
1051 | ||
1052 | /* If we just entered a run of characters covered by a display | |
1053 | string, compute the position of the next display string. */ | |
55439c61 | 1054 | if (charpos + *nchars <= endpos && charpos + *nchars > *disp_pos |
0c95fcf7 | 1055 | && *disp_prop) |
6db161be EZ |
1056 | { |
1057 | SET_TEXT_POS (pos, charpos + *nchars, bytepos + *ch_len); | |
5bf97bfc | 1058 | *disp_pos = compute_display_string_pos (&pos, string, w, frame_window_p, |
0c95fcf7 | 1059 | disp_prop); |
6db161be | 1060 | } |
182ce2d2 EZ |
1061 | |
1062 | return ch; | |
1063 | } | |
1064 | ||
cbb09f04 EZ |
1065 | \f |
1066 | /*********************************************************************** | |
1067 | Determining paragraph direction | |
1068 | ***********************************************************************/ | |
1069 | ||
1070 | /* Check if buffer position CHARPOS/BYTEPOS is the end of a paragraph. | |
1071 | Value is the non-negative length of the paragraph separator | |
1072 | following the buffer position, -1 if position is at the beginning | |
1073 | of a new paragraph, or -2 if position is neither at beginning nor | |
1074 | at end of a paragraph. */ | |
d311d28c PE |
1075 | static ptrdiff_t |
1076 | bidi_at_paragraph_end (ptrdiff_t charpos, ptrdiff_t bytepos) | |
cbb09f04 EZ |
1077 | { |
1078 | Lisp_Object sep_re; | |
1079 | Lisp_Object start_re; | |
d311d28c | 1080 | ptrdiff_t val; |
cbb09f04 EZ |
1081 | |
1082 | sep_re = paragraph_separate_re; | |
1083 | start_re = paragraph_start_re; | |
1084 | ||
1085 | val = fast_looking_at (sep_re, charpos, bytepos, ZV, ZV_BYTE, Qnil); | |
1086 | if (val < 0) | |
1087 | { | |
1088 | if (fast_looking_at (start_re, charpos, bytepos, ZV, ZV_BYTE, Qnil) >= 0) | |
1089 | val = -1; | |
1090 | else | |
1091 | val = -2; | |
1092 | } | |
1093 | ||
1094 | return val; | |
1095 | } | |
1096 | ||
e30b79c1 DA |
1097 | /* If the user has requested the long scans caching, make sure that |
1098 | BIDI cache is enabled. Otherwise, make sure it's disabled. */ | |
1099 | ||
1100 | static struct region_cache * | |
1101 | bidi_paragraph_cache_on_off (void) | |
1102 | { | |
c10e9ece EZ |
1103 | struct buffer *cache_buffer = current_buffer; |
1104 | bool indirect_p = false; | |
1105 | ||
1106 | /* For indirect buffers, make sure to use the cache of their base | |
1107 | buffer. */ | |
1108 | if (cache_buffer->base_buffer) | |
1109 | { | |
1110 | cache_buffer = cache_buffer->base_buffer; | |
1111 | indirect_p = true; | |
1112 | } | |
1113 | ||
1114 | /* Don't turn on or off the cache in the base buffer, if the value | |
1115 | of cache-long-scans of the base buffer is inconsistent with that. | |
1116 | This is because doing so will just make the cache pure overhead, | |
1117 | since if we turn it on via indirect buffer, it will be | |
1118 | immediately turned off by its base buffer. */ | |
e30b79c1 DA |
1119 | if (NILP (BVAR (current_buffer, cache_long_scans))) |
1120 | { | |
c10e9ece EZ |
1121 | if (!indirect_p |
1122 | || NILP (BVAR (cache_buffer, cache_long_scans))) | |
e30b79c1 | 1123 | { |
c10e9ece EZ |
1124 | if (cache_buffer->bidi_paragraph_cache) |
1125 | { | |
1126 | free_region_cache (cache_buffer->bidi_paragraph_cache); | |
1127 | cache_buffer->bidi_paragraph_cache = 0; | |
1128 | } | |
e30b79c1 DA |
1129 | } |
1130 | return NULL; | |
1131 | } | |
1132 | else | |
1133 | { | |
c10e9ece EZ |
1134 | if (!indirect_p |
1135 | || !NILP (BVAR (cache_buffer, cache_long_scans))) | |
1136 | { | |
1137 | if (!cache_buffer->bidi_paragraph_cache) | |
1138 | cache_buffer->bidi_paragraph_cache = new_region_cache (); | |
1139 | } | |
1140 | return cache_buffer->bidi_paragraph_cache; | |
e30b79c1 DA |
1141 | } |
1142 | } | |
1143 | ||
1137e8b8 EZ |
1144 | /* On my 2005-vintage machine, searching back for paragraph start |
1145 | takes ~1 ms per line. And bidi_paragraph_init is called 4 times | |
1146 | when user types C-p. The number below limits each call to | |
1147 | bidi_paragraph_init to about 10 ms. */ | |
1148 | #define MAX_PARAGRAPH_SEARCH 7500 | |
1149 | ||
be39f003 | 1150 | /* Find the beginning of this paragraph by looking back in the buffer. |
1137e8b8 EZ |
1151 | Value is the byte position of the paragraph's beginning, or |
1152 | BEGV_BYTE if paragraph_start_re is still not found after looking | |
1153 | back MAX_PARAGRAPH_SEARCH lines in the buffer. */ | |
d311d28c PE |
1154 | static ptrdiff_t |
1155 | bidi_find_paragraph_start (ptrdiff_t pos, ptrdiff_t pos_byte) | |
6bff6497 | 1156 | { |
372b7a95 | 1157 | Lisp_Object re = paragraph_start_re; |
d311d28c | 1158 | ptrdiff_t limit = ZV, limit_byte = ZV_BYTE; |
e30b79c1 DA |
1159 | struct region_cache *bpc = bidi_paragraph_cache_on_off (); |
1160 | ptrdiff_t n = 0, oldpos = pos, next; | |
c10e9ece EZ |
1161 | struct buffer *cache_buffer = current_buffer; |
1162 | ||
1163 | if (cache_buffer->base_buffer) | |
1164 | cache_buffer = cache_buffer->base_buffer; | |
6bff6497 | 1165 | |
6bff6497 | 1166 | while (pos_byte > BEGV_BYTE |
1137e8b8 | 1167 | && n++ < MAX_PARAGRAPH_SEARCH |
6bff6497 | 1168 | && fast_looking_at (re, pos, pos_byte, limit, limit_byte, Qnil) < 0) |
b5426561 DA |
1169 | { |
1170 | /* FIXME: What if the paragraph beginning is covered by a | |
1171 | display string? And what if a display string covering some | |
1172 | of the text over which we scan back includes | |
1173 | paragraph_start_re? */ | |
1174 | DEC_BOTH (pos, pos_byte); | |
c10e9ece | 1175 | if (bpc && region_cache_backward (cache_buffer, bpc, pos, &next)) |
e30b79c1 DA |
1176 | { |
1177 | pos = next, pos_byte = CHAR_TO_BYTE (pos); | |
1178 | break; | |
1179 | } | |
1180 | else | |
1181 | pos = find_newline_no_quit (pos, pos_byte, -1, &pos_byte); | |
b5426561 | 1182 | } |
1137e8b8 | 1183 | if (n >= MAX_PARAGRAPH_SEARCH) |
e30b79c1 DA |
1184 | pos = BEGV, pos_byte = BEGV_BYTE; |
1185 | if (bpc) | |
c10e9ece | 1186 | know_region_cache (cache_buffer, bpc, pos, oldpos); |
cd88d682 EZ |
1187 | /* Positions returned by the region cache are not limited to |
1188 | BEGV..ZV range, so we limit them here. */ | |
1189 | pos_byte = clip_to_bounds (BEGV_BYTE, pos_byte, ZV_BYTE); | |
be39f003 | 1190 | return pos_byte; |
6bff6497 EZ |
1191 | } |
1192 | ||
ce811ad9 EZ |
1193 | /* On a 3.4 GHz machine, searching forward for a strong directional |
1194 | character in a long paragraph full of weaks or neutrals takes about | |
1195 | 1 ms for each 20K characters. The number below limits each call to | |
1196 | bidi_paragraph_init to less than 10 ms even on slow machines. */ | |
1197 | #define MAX_STRONG_CHAR_SEARCH 100000 | |
1198 | ||
bea4f10c | 1199 | /* Determine the base direction, a.k.a. base embedding level, of the |
b44d9321 EZ |
1200 | paragraph we are about to iterate through. If DIR is either L2R or |
1201 | R2L, just use that. Otherwise, determine the paragraph direction | |
bea4f10c EZ |
1202 | from the first strong directional character of the paragraph. |
1203 | ||
2cc21167 | 1204 | NO_DEFAULT_P means don't default to L2R if the paragraph |
bea4f10c EZ |
1205 | has no strong directional characters and both DIR and |
1206 | bidi_it->paragraph_dir are NEUTRAL_DIR. In that case, search back | |
1207 | in the buffer until a paragraph is found with a strong character, | |
1208 | or until hitting BEGV. In the latter case, fall back to L2R. This | |
1209 | flag is used in current-bidi-paragraph-direction. | |
1210 | ||
1211 | Note that this function gives the paragraph separator the same | |
1212 | direction as the preceding paragraph, even though Emacs generally | |
9858f6c3 | 1213 | views the separator as not belonging to any paragraph. */ |
b7b65b15 | 1214 | void |
2cc21167 | 1215 | bidi_paragraph_init (bidi_dir_t dir, struct bidi_it *bidi_it, bool no_default_p) |
b7b65b15 | 1216 | { |
d311d28c | 1217 | ptrdiff_t bytepos = bidi_it->bytepos; |
2cc21167 | 1218 | bool string_p = bidi_it->string.s || STRINGP (bidi_it->string.lstring); |
d311d28c | 1219 | ptrdiff_t pstartbyte; |
87e67904 EZ |
1220 | /* Note that begbyte is a byte position, while end is a character |
1221 | position. Yes, this is ugly, but we are trying to avoid costly | |
1222 | calls to BYTE_TO_CHAR and its ilk. */ | |
d311d28c PE |
1223 | ptrdiff_t begbyte = string_p ? 0 : BEGV_BYTE; |
1224 | ptrdiff_t end = string_p ? bidi_it->string.schars : ZV; | |
e7402cb2 | 1225 | |
5e65aec0 | 1226 | /* Special case for an empty buffer. */ |
87e67904 | 1227 | if (bytepos == begbyte && bidi_it->charpos == end) |
5e65aec0 | 1228 | dir = L2R; |
9c82e145 | 1229 | /* We should never be called at EOB or before BEGV. */ |
87e67904 | 1230 | else if (bidi_it->charpos >= end || bytepos < begbyte) |
1088b922 | 1231 | emacs_abort (); |
9c82e145 | 1232 | |
be39f003 EZ |
1233 | if (dir == L2R) |
1234 | { | |
1235 | bidi_it->paragraph_dir = L2R; | |
1236 | bidi_it->new_paragraph = 0; | |
1237 | } | |
1238 | else if (dir == R2L) | |
1239 | { | |
1240 | bidi_it->paragraph_dir = R2L; | |
1241 | bidi_it->new_paragraph = 0; | |
1242 | } | |
b7b65b15 EZ |
1243 | else if (dir == NEUTRAL_DIR) /* P2 */ |
1244 | { | |
182ce2d2 | 1245 | int ch; |
d311d28c PE |
1246 | ptrdiff_t ch_len, nchars; |
1247 | ptrdiff_t pos, disp_pos = -1; | |
0c95fcf7 | 1248 | int disp_prop = 0; |
6bff6497 | 1249 | bidi_type_t type; |
9f257352 | 1250 | const unsigned char *s; |
be39f003 | 1251 | |
d20e1419 EZ |
1252 | if (!bidi_initialized) |
1253 | bidi_initialize (); | |
1254 | ||
be39f003 EZ |
1255 | /* If we are inside a paragraph separator, we are just waiting |
1256 | for the separator to be exhausted; use the previous paragraph | |
e5a2fec7 EZ |
1257 | direction. But don't do that if we have been just reseated, |
1258 | because we need to reinitialize below in that case. */ | |
1259 | if (!bidi_it->first_elt | |
1260 | && bidi_it->charpos < bidi_it->separator_limit) | |
be39f003 EZ |
1261 | return; |
1262 | ||
b44d9321 | 1263 | /* If we are on a newline, get past it to where the next |
5e65aec0 EZ |
1264 | paragraph might start. But don't do that at BEGV since then |
1265 | we are potentially in a new paragraph that doesn't yet | |
1266 | exist. */ | |
c143c213 | 1267 | pos = bidi_it->charpos; |
512a289d RS |
1268 | s = (STRINGP (bidi_it->string.lstring) |
1269 | ? SDATA (bidi_it->string.lstring) | |
1270 | : bidi_it->string.s); | |
f3014ef5 EZ |
1271 | if (bytepos > begbyte |
1272 | && bidi_char_at_pos (bytepos, s, bidi_it->string.unibyte) == '\n') | |
be39f003 | 1273 | { |
b44d9321 | 1274 | bytepos++; |
c143c213 | 1275 | pos++; |
be39f003 | 1276 | } |
b44d9321 EZ |
1277 | |
1278 | /* We are either at the beginning of a paragraph or in the | |
1279 | middle of it. Find where this paragraph starts. */ | |
87e67904 EZ |
1280 | if (string_p) |
1281 | { | |
1282 | /* We don't support changes of paragraph direction inside a | |
1283 | string. It is treated as a single paragraph. */ | |
1284 | pstartbyte = 0; | |
1285 | } | |
1286 | else | |
1287 | pstartbyte = bidi_find_paragraph_start (pos, bytepos); | |
be39f003 EZ |
1288 | bidi_it->separator_limit = -1; |
1289 | bidi_it->new_paragraph = 0; | |
bea4f10c | 1290 | |
2cc21167 PE |
1291 | /* The following loop is run more than once only if NO_DEFAULT_P, |
1292 | and only if we are iterating on a buffer. */ | |
bea4f10c | 1293 | do { |
ce811ad9 EZ |
1294 | ptrdiff_t pos1; |
1295 | ||
bea4f10c | 1296 | bytepos = pstartbyte; |
87e67904 EZ |
1297 | if (!string_p) |
1298 | pos = BYTE_TO_CHAR (bytepos); | |
36075a19 | 1299 | ch = bidi_fetch_char (pos, bytepos, &disp_pos, &disp_prop, |
5bf97bfc | 1300 | &bidi_it->string, bidi_it->w, |
87e67904 | 1301 | bidi_it->frame_window_p, &ch_len, &nchars); |
bea4f10c EZ |
1302 | type = bidi_get_type (ch, NEUTRAL_DIR); |
1303 | ||
ce811ad9 | 1304 | pos1 = pos; |
182ce2d2 | 1305 | for (pos += nchars, bytepos += ch_len; |
ce811ad9 EZ |
1306 | ((bidi_get_category (type) != STRONG) |
1307 | || (bidi_ignore_explicit_marks_for_paragraph_level | |
1308 | && (type == RLE || type == RLO | |
1309 | || type == LRE || type == LRO))) | |
1310 | /* Stop when searched too far into an abnormally large | |
1311 | paragraph full of weak or neutral characters. */ | |
1312 | && pos - pos1 < MAX_STRONG_CHAR_SEARCH; | |
bea4f10c EZ |
1313 | type = bidi_get_type (ch, NEUTRAL_DIR)) |
1314 | { | |
87e67904 | 1315 | if (pos >= end) |
bea4f10c EZ |
1316 | { |
1317 | /* Pretend there's a paragraph separator at end of | |
87e67904 | 1318 | buffer/string. */ |
bea4f10c EZ |
1319 | type = NEUTRAL_B; |
1320 | break; | |
1321 | } | |
0bb23927 EZ |
1322 | if (!string_p |
1323 | && type == NEUTRAL_B | |
1324 | && bidi_at_paragraph_end (pos, bytepos) >= -1) | |
cf99dcf8 | 1325 | break; |
102ebb00 | 1326 | /* Fetch next character and advance to get past it. */ |
36075a19 | 1327 | ch = bidi_fetch_char (pos, bytepos, &disp_pos, |
5bf97bfc | 1328 | &disp_prop, &bidi_it->string, bidi_it->w, |
fc6f18ce | 1329 | bidi_it->frame_window_p, &ch_len, &nchars); |
182ce2d2 EZ |
1330 | pos += nchars; |
1331 | bytepos += ch_len; | |
bea4f10c | 1332 | } |
32413314 EZ |
1333 | if ((type == STRONG_R || type == STRONG_AL) /* P3 */ |
1334 | || (!bidi_ignore_explicit_marks_for_paragraph_level | |
1335 | && (type == RLO || type == RLE))) | |
bea4f10c | 1336 | bidi_it->paragraph_dir = R2L; |
32413314 EZ |
1337 | else if (type == STRONG_L |
1338 | || (!bidi_ignore_explicit_marks_for_paragraph_level | |
1339 | && (type == LRO || type == LRE))) | |
bea4f10c | 1340 | bidi_it->paragraph_dir = L2R; |
87e67904 EZ |
1341 | if (!string_p |
1342 | && no_default_p && bidi_it->paragraph_dir == NEUTRAL_DIR) | |
bea4f10c EZ |
1343 | { |
1344 | /* If this paragraph is at BEGV, default to L2R. */ | |
1345 | if (pstartbyte == BEGV_BYTE) | |
1346 | bidi_it->paragraph_dir = L2R; /* P3 and HL1 */ | |
1347 | else | |
1348 | { | |
d311d28c PE |
1349 | ptrdiff_t prevpbyte = pstartbyte; |
1350 | ptrdiff_t p = BYTE_TO_CHAR (pstartbyte), pbyte = pstartbyte; | |
bea4f10c EZ |
1351 | |
1352 | /* Find the beginning of the previous paragraph, if any. */ | |
1353 | while (pbyte > BEGV_BYTE && prevpbyte >= pstartbyte) | |
1354 | { | |
182ce2d2 EZ |
1355 | /* FXIME: What if p is covered by a display |
1356 | string? See also a FIXME inside | |
1357 | bidi_find_paragraph_start. */ | |
36075a19 | 1358 | DEC_BOTH (p, pbyte); |
bea4f10c EZ |
1359 | prevpbyte = bidi_find_paragraph_start (p, pbyte); |
1360 | } | |
1361 | pstartbyte = prevpbyte; | |
1362 | } | |
1363 | } | |
87e67904 EZ |
1364 | } while (!string_p |
1365 | && no_default_p && bidi_it->paragraph_dir == NEUTRAL_DIR); | |
b7b65b15 | 1366 | } |
be39f003 | 1367 | else |
1088b922 | 1368 | emacs_abort (); |
b7b65b15 | 1369 | |
b44d9321 EZ |
1370 | /* Contrary to UAX#9 clause P3, we only default the paragraph |
1371 | direction to L2R if we have no previous usable paragraph | |
bea4f10c | 1372 | direction. This is allowed by the HL1 clause. */ |
d20e1419 | 1373 | if (bidi_it->paragraph_dir != L2R && bidi_it->paragraph_dir != R2L) |
bea4f10c | 1374 | bidi_it->paragraph_dir = L2R; /* P3 and HL1 ``higher-level protocols'' */ |
be39f003 | 1375 | if (bidi_it->paragraph_dir == R2L) |
b44d9321 | 1376 | bidi_it->level_stack[0].level = 1; |
be39f003 | 1377 | else |
b44d9321 | 1378 | bidi_it->level_stack[0].level = 0; |
be39f003 EZ |
1379 | |
1380 | bidi_line_init (bidi_it); | |
b7b65b15 EZ |
1381 | } |
1382 | ||
cbb09f04 EZ |
1383 | \f |
1384 | /*********************************************************************** | |
1385 | Resolving explicit and implicit levels. | |
58b9f433 | 1386 | The rest of this file constitutes the core of the UBA implementation. |
cbb09f04 | 1387 | ***********************************************************************/ |
b7b65b15 | 1388 | |
0a99eee1 | 1389 | static bool |
182ce2d2 | 1390 | bidi_explicit_dir_char (int ch) |
b7b65b15 | 1391 | { |
182ce2d2 EZ |
1392 | bidi_type_t ch_type; |
1393 | ||
1394 | if (!bidi_initialized) | |
1088b922 | 1395 | emacs_abort (); |
182ce2d2 EZ |
1396 | ch_type = (bidi_type_t) XINT (CHAR_TABLE_REF (bidi_type_table, ch)); |
1397 | return (ch_type == LRE || ch_type == LRO | |
1398 | || ch_type == RLE || ch_type == RLO | |
1399 | || ch_type == PDF); | |
b7b65b15 EZ |
1400 | } |
1401 | ||
1402 | /* A helper function for bidi_resolve_explicit. It advances to the | |
1403 | next character in logical order and determines the new embedding | |
1404 | level and directional override, but does not take into account | |
1405 | empty embeddings. */ | |
1406 | static int | |
1407 | bidi_resolve_explicit_1 (struct bidi_it *bidi_it) | |
1408 | { | |
1409 | int curchar; | |
1410 | bidi_type_t type; | |
1411 | int current_level; | |
1412 | int new_level; | |
1413 | bidi_dir_t override; | |
2cc21167 | 1414 | bool string_p = bidi_it->string.s || STRINGP (bidi_it->string.lstring); |
b7b65b15 | 1415 | |
182ce2d2 EZ |
1416 | /* If reseat()'ed, don't advance, so as to start iteration from the |
1417 | position where we were reseated. bidi_it->bytepos can be less | |
1418 | than BEGV_BYTE after reseat to BEGV. */ | |
87e67904 | 1419 | if (bidi_it->bytepos < (string_p ? 0 : BEGV_BYTE) |
9c82e145 | 1420 | || bidi_it->first_elt) |
e7402cb2 | 1421 | { |
9c82e145 | 1422 | bidi_it->first_elt = 0; |
87e67904 EZ |
1423 | if (string_p) |
1424 | { | |
512a289d RS |
1425 | const unsigned char *p |
1426 | = (STRINGP (bidi_it->string.lstring) | |
1427 | ? SDATA (bidi_it->string.lstring) | |
1428 | : bidi_it->string.s); | |
9f257352 | 1429 | |
87e67904 | 1430 | if (bidi_it->charpos < 0) |
05e193f1 EZ |
1431 | bidi_it->charpos = bidi_it->bytepos = 0; |
1432 | eassert (bidi_it->bytepos == bidi_count_bytes (p, 0, 0, | |
1433 | bidi_it->charpos, | |
1434 | bidi_it->string.unibyte)); | |
87e67904 EZ |
1435 | } |
1436 | else | |
1437 | { | |
1438 | if (bidi_it->charpos < BEGV) | |
05e193f1 EZ |
1439 | { |
1440 | bidi_it->charpos = BEGV; | |
1441 | bidi_it->bytepos = BEGV_BYTE; | |
1442 | } | |
1443 | eassert (bidi_it->bytepos == CHAR_TO_BYTE (bidi_it->charpos)); | |
87e67904 | 1444 | } |
e7402cb2 | 1445 | } |
87e67904 EZ |
1446 | /* Don't move at end of buffer/string. */ |
1447 | else if (bidi_it->charpos < (string_p ? bidi_it->string.schars : ZV)) | |
b7b65b15 | 1448 | { |
182ce2d2 EZ |
1449 | /* Advance to the next character, skipping characters covered by |
1450 | display strings (nchars > 1). */ | |
102ebb00 | 1451 | if (bidi_it->nchars <= 0) |
1088b922 | 1452 | emacs_abort (); |
182ce2d2 | 1453 | bidi_it->charpos += bidi_it->nchars; |
e7402cb2 | 1454 | if (bidi_it->ch_len == 0) |
1088b922 | 1455 | emacs_abort (); |
b7b65b15 EZ |
1456 | bidi_it->bytepos += bidi_it->ch_len; |
1457 | } | |
1458 | ||
1459 | current_level = bidi_it->level_stack[bidi_it->stack_idx].level; /* X1 */ | |
1460 | override = bidi_it->level_stack[bidi_it->stack_idx].override; | |
1461 | new_level = current_level; | |
1462 | ||
87e67904 | 1463 | if (bidi_it->charpos >= (string_p ? bidi_it->string.schars : ZV)) |
e7402cb2 EZ |
1464 | { |
1465 | curchar = BIDI_EOB; | |
1466 | bidi_it->ch_len = 1; | |
182ce2d2 | 1467 | bidi_it->nchars = 1; |
87e67904 | 1468 | bidi_it->disp_pos = (string_p ? bidi_it->string.schars : ZV); |
0c95fcf7 | 1469 | bidi_it->disp_prop = 0; |
e7402cb2 EZ |
1470 | } |
1471 | else | |
1472 | { | |
182ce2d2 EZ |
1473 | /* Fetch the character at BYTEPOS. If it is covered by a |
1474 | display string, treat the entire run of covered characters as | |
1475 | a single character u+FFFC. */ | |
36075a19 | 1476 | curchar = bidi_fetch_char (bidi_it->charpos, bidi_it->bytepos, |
0c95fcf7 | 1477 | &bidi_it->disp_pos, &bidi_it->disp_prop, |
5bf97bfc EZ |
1478 | &bidi_it->string, bidi_it->w, |
1479 | bidi_it->frame_window_p, | |
102ebb00 | 1480 | &bidi_it->ch_len, &bidi_it->nchars); |
e7402cb2 | 1481 | } |
b7b65b15 | 1482 | bidi_it->ch = curchar; |
b7b65b15 | 1483 | |
6bff6497 EZ |
1484 | /* Don't apply directional override here, as all the types we handle |
1485 | below will not be affected by the override anyway, and we need | |
1486 | the original type unaltered. The override will be applied in | |
1487 | bidi_resolve_weak. */ | |
1488 | type = bidi_get_type (curchar, NEUTRAL_DIR); | |
89d3374a EZ |
1489 | bidi_it->orig_type = type; |
1490 | bidi_check_type (bidi_it->orig_type); | |
b7b65b15 EZ |
1491 | |
1492 | if (type != PDF) | |
1493 | bidi_it->prev_was_pdf = 0; | |
1494 | ||
89d3374a | 1495 | bidi_it->type_after_w1 = UNKNOWN_BT; |
b7b65b15 EZ |
1496 | |
1497 | switch (type) | |
1498 | { | |
1499 | case RLE: /* X2 */ | |
1500 | case RLO: /* X4 */ | |
89d3374a EZ |
1501 | bidi_it->type_after_w1 = type; |
1502 | bidi_check_type (bidi_it->type_after_w1); | |
b7b65b15 | 1503 | type = WEAK_BN; /* X9/Retaining */ |
87e67904 | 1504 | if (bidi_it->ignore_bn_limit <= -1) |
b7b65b15 EZ |
1505 | { |
1506 | if (current_level <= BIDI_MAXLEVEL - 4) | |
1507 | { | |
1508 | /* Compute the least odd embedding level greater than | |
1509 | the current level. */ | |
1510 | new_level = ((current_level + 1) & ~1) + 1; | |
89d3374a | 1511 | if (bidi_it->type_after_w1 == RLE) |
b7b65b15 EZ |
1512 | override = NEUTRAL_DIR; |
1513 | else | |
1514 | override = R2L; | |
1515 | if (current_level == BIDI_MAXLEVEL - 4) | |
1516 | bidi_it->invalid_rl_levels = 0; | |
1517 | bidi_push_embedding_level (bidi_it, new_level, override); | |
1518 | } | |
1519 | else | |
1520 | { | |
1521 | bidi_it->invalid_levels++; | |
1522 | /* See the commentary about invalid_rl_levels below. */ | |
1523 | if (bidi_it->invalid_rl_levels < 0) | |
1524 | bidi_it->invalid_rl_levels = 0; | |
1525 | bidi_it->invalid_rl_levels++; | |
1526 | } | |
1527 | } | |
89d3374a | 1528 | else if (bidi_it->prev.type_after_w1 == WEAK_EN /* W5/Retaining */ |
7b5d6677 EZ |
1529 | || (bidi_it->next_en_pos > bidi_it->charpos |
1530 | && bidi_it->next_en_type == WEAK_EN)) | |
b7b65b15 EZ |
1531 | type = WEAK_EN; |
1532 | break; | |
1533 | case LRE: /* X3 */ | |
1534 | case LRO: /* X5 */ | |
89d3374a EZ |
1535 | bidi_it->type_after_w1 = type; |
1536 | bidi_check_type (bidi_it->type_after_w1); | |
b7b65b15 | 1537 | type = WEAK_BN; /* X9/Retaining */ |
87e67904 | 1538 | if (bidi_it->ignore_bn_limit <= -1) |
b7b65b15 EZ |
1539 | { |
1540 | if (current_level <= BIDI_MAXLEVEL - 5) | |
1541 | { | |
1542 | /* Compute the least even embedding level greater than | |
1543 | the current level. */ | |
1544 | new_level = ((current_level + 2) & ~1); | |
89d3374a | 1545 | if (bidi_it->type_after_w1 == LRE) |
b7b65b15 EZ |
1546 | override = NEUTRAL_DIR; |
1547 | else | |
1548 | override = L2R; | |
1549 | bidi_push_embedding_level (bidi_it, new_level, override); | |
1550 | } | |
1551 | else | |
1552 | { | |
1553 | bidi_it->invalid_levels++; | |
1554 | /* invalid_rl_levels counts invalid levels encountered | |
1555 | while the embedding level was already too high for | |
1556 | LRE/LRO, but not for RLE/RLO. That is because | |
1557 | there may be exactly one PDF which we should not | |
1558 | ignore even though invalid_levels is non-zero. | |
1559 | invalid_rl_levels helps to know what PDF is | |
1560 | that. */ | |
1561 | if (bidi_it->invalid_rl_levels >= 0) | |
1562 | bidi_it->invalid_rl_levels++; | |
1563 | } | |
1564 | } | |
89d3374a | 1565 | else if (bidi_it->prev.type_after_w1 == WEAK_EN /* W5/Retaining */ |
7b5d6677 EZ |
1566 | || (bidi_it->next_en_pos > bidi_it->charpos |
1567 | && bidi_it->next_en_type == WEAK_EN)) | |
b7b65b15 EZ |
1568 | type = WEAK_EN; |
1569 | break; | |
1570 | case PDF: /* X7 */ | |
89d3374a EZ |
1571 | bidi_it->type_after_w1 = type; |
1572 | bidi_check_type (bidi_it->type_after_w1); | |
b7b65b15 | 1573 | type = WEAK_BN; /* X9/Retaining */ |
87e67904 | 1574 | if (bidi_it->ignore_bn_limit <= -1) |
b7b65b15 EZ |
1575 | { |
1576 | if (!bidi_it->invalid_rl_levels) | |
1577 | { | |
1578 | new_level = bidi_pop_embedding_level (bidi_it); | |
1579 | bidi_it->invalid_rl_levels = -1; | |
1580 | if (bidi_it->invalid_levels) | |
1581 | bidi_it->invalid_levels--; | |
1582 | /* else nothing: UAX#9 says to ignore invalid PDFs */ | |
1583 | } | |
1584 | if (!bidi_it->invalid_levels) | |
1585 | new_level = bidi_pop_embedding_level (bidi_it); | |
1586 | else | |
1587 | { | |
1588 | bidi_it->invalid_levels--; | |
1589 | bidi_it->invalid_rl_levels--; | |
1590 | } | |
1591 | } | |
89d3374a | 1592 | else if (bidi_it->prev.type_after_w1 == WEAK_EN /* W5/Retaining */ |
7b5d6677 EZ |
1593 | || (bidi_it->next_en_pos > bidi_it->charpos |
1594 | && bidi_it->next_en_type == WEAK_EN)) | |
b7b65b15 EZ |
1595 | type = WEAK_EN; |
1596 | break; | |
1597 | default: | |
1598 | /* Nothing. */ | |
1599 | break; | |
1600 | } | |
1601 | ||
1602 | bidi_it->type = type; | |
2d6e4628 | 1603 | bidi_check_type (bidi_it->type); |
b7b65b15 EZ |
1604 | |
1605 | return new_level; | |
1606 | } | |
1607 | ||
1608 | /* Given an iterator state in BIDI_IT, advance one character position | |
182ce2d2 EZ |
1609 | in the buffer/string to the next character (in the logical order), |
1610 | resolve any explicit embeddings and directional overrides, and | |
1611 | return the embedding level of the character after resolving | |
1612 | explicit directives and ignoring empty embeddings. */ | |
b7b65b15 EZ |
1613 | static int |
1614 | bidi_resolve_explicit (struct bidi_it *bidi_it) | |
1615 | { | |
1616 | int prev_level = bidi_it->level_stack[bidi_it->stack_idx].level; | |
1617 | int new_level = bidi_resolve_explicit_1 (bidi_it); | |
d311d28c | 1618 | ptrdiff_t eob = bidi_it->string.s ? bidi_it->string.schars : ZV; |
512a289d RS |
1619 | const unsigned char *s |
1620 | = (STRINGP (bidi_it->string.lstring) | |
1621 | ? SDATA (bidi_it->string.lstring) | |
1622 | : bidi_it->string.s); | |
b7b65b15 EZ |
1623 | |
1624 | if (prev_level < new_level | |
1625 | && bidi_it->type == WEAK_BN | |
87e67904 EZ |
1626 | && bidi_it->ignore_bn_limit == -1 /* only if not already known */ |
1627 | && bidi_it->charpos < eob /* not already at EOB */ | |
1628 | && bidi_explicit_dir_char (bidi_char_at_pos (bidi_it->bytepos | |
f3014ef5 EZ |
1629 | + bidi_it->ch_len, s, |
1630 | bidi_it->string.unibyte))) | |
b7b65b15 EZ |
1631 | { |
1632 | /* Avoid pushing and popping embedding levels if the level run | |
1633 | is empty, as this breaks level runs where it shouldn't. | |
1634 | UAX#9 removes all the explicit embedding and override codes, | |
1635 | so empty embeddings disappear without a trace. We need to | |
1636 | behave as if we did the same. */ | |
1637 | struct bidi_it saved_it; | |
1638 | int level = prev_level; | |
1639 | ||
1640 | bidi_copy_it (&saved_it, bidi_it); | |
1641 | ||
87e67904 | 1642 | while (bidi_explicit_dir_char (bidi_char_at_pos (bidi_it->bytepos |
f3014ef5 EZ |
1643 | + bidi_it->ch_len, s, |
1644 | bidi_it->string.unibyte))) | |
b7b65b15 | 1645 | { |
182ce2d2 EZ |
1646 | /* This advances to the next character, skipping any |
1647 | characters covered by display strings. */ | |
b7b65b15 | 1648 | level = bidi_resolve_explicit_1 (bidi_it); |
9f257352 EZ |
1649 | /* If string.lstring was relocated inside bidi_resolve_explicit_1, |
1650 | a pointer to its data is no longer valid. */ | |
1651 | if (STRINGP (bidi_it->string.lstring)) | |
1652 | s = SDATA (bidi_it->string.lstring); | |
b7b65b15 EZ |
1653 | } |
1654 | ||
102ebb00 | 1655 | if (bidi_it->nchars <= 0) |
1088b922 | 1656 | emacs_abort (); |
b7b65b15 | 1657 | if (level == prev_level) /* empty embedding */ |
182ce2d2 | 1658 | saved_it.ignore_bn_limit = bidi_it->charpos + bidi_it->nchars; |
b7b65b15 | 1659 | else /* this embedding is non-empty */ |
87e67904 | 1660 | saved_it.ignore_bn_limit = -2; |
b7b65b15 EZ |
1661 | |
1662 | bidi_copy_it (bidi_it, &saved_it); | |
87e67904 | 1663 | if (bidi_it->ignore_bn_limit > -1) |
b7b65b15 EZ |
1664 | { |
1665 | /* We pushed a level, but we shouldn't have. Undo that. */ | |
1666 | if (!bidi_it->invalid_rl_levels) | |
1667 | { | |
1668 | new_level = bidi_pop_embedding_level (bidi_it); | |
1669 | bidi_it->invalid_rl_levels = -1; | |
1670 | if (bidi_it->invalid_levels) | |
1671 | bidi_it->invalid_levels--; | |
1672 | } | |
1673 | if (!bidi_it->invalid_levels) | |
1674 | new_level = bidi_pop_embedding_level (bidi_it); | |
1675 | else | |
1676 | { | |
1677 | bidi_it->invalid_levels--; | |
1678 | bidi_it->invalid_rl_levels--; | |
1679 | } | |
1680 | } | |
1681 | } | |
1682 | ||
b7b65b15 EZ |
1683 | if (bidi_it->type == NEUTRAL_B) /* X8 */ |
1684 | { | |
21fce5ab | 1685 | bidi_set_paragraph_end (bidi_it); |
6bff6497 EZ |
1686 | /* This is needed by bidi_resolve_weak below, and in L1. */ |
1687 | bidi_it->type_after_w1 = bidi_it->type; | |
89d3374a | 1688 | bidi_check_type (bidi_it->type_after_w1); |
b7b65b15 EZ |
1689 | } |
1690 | ||
1691 | return new_level; | |
1692 | } | |
1693 | ||
182ce2d2 EZ |
1694 | /* Advance in the buffer/string, resolve weak types and return the |
1695 | type of the next character after weak type resolution. */ | |
fd3998ff | 1696 | static bidi_type_t |
b7b65b15 EZ |
1697 | bidi_resolve_weak (struct bidi_it *bidi_it) |
1698 | { | |
1699 | bidi_type_t type; | |
1700 | bidi_dir_t override; | |
1701 | int prev_level = bidi_it->level_stack[bidi_it->stack_idx].level; | |
1702 | int new_level = bidi_resolve_explicit (bidi_it); | |
1703 | int next_char; | |
1704 | bidi_type_t type_of_next; | |
1705 | struct bidi_it saved_it; | |
5895d7b9 | 1706 | ptrdiff_t eob |
512a289d RS |
1707 | = ((STRINGP (bidi_it->string.lstring) || bidi_it->string.s) |
1708 | ? bidi_it->string.schars : ZV); | |
b7b65b15 EZ |
1709 | |
1710 | type = bidi_it->type; | |
1711 | override = bidi_it->level_stack[bidi_it->stack_idx].override; | |
1712 | ||
1713 | if (type == UNKNOWN_BT | |
1714 | || type == LRE | |
1715 | || type == LRO | |
1716 | || type == RLE | |
1717 | || type == RLO | |
1718 | || type == PDF) | |
1088b922 | 1719 | emacs_abort (); |
b7b65b15 EZ |
1720 | |
1721 | if (new_level != prev_level | |
1722 | || bidi_it->type == NEUTRAL_B) | |
1723 | { | |
1724 | /* We've got a new embedding level run, compute the directional | |
1725 | type of sor and initialize per-run variables (UAX#9, clause | |
1726 | X10). */ | |
1727 | bidi_set_sor_type (bidi_it, prev_level, new_level); | |
1728 | } | |
1729 | else if (type == NEUTRAL_S || type == NEUTRAL_WS | |
1730 | || type == WEAK_BN || type == STRONG_AL) | |
89d3374a EZ |
1731 | bidi_it->type_after_w1 = type; /* needed in L1 */ |
1732 | bidi_check_type (bidi_it->type_after_w1); | |
b7b65b15 EZ |
1733 | |
1734 | /* Level and directional override status are already recorded in | |
1735 | bidi_it, and do not need any change; see X6. */ | |
1736 | if (override == R2L) /* X6 */ | |
1737 | type = STRONG_R; | |
1738 | else if (override == L2R) | |
1739 | type = STRONG_L; | |
bc5a45f3 | 1740 | else |
b7b65b15 | 1741 | { |
bc5a45f3 | 1742 | if (type == WEAK_NSM) /* W1 */ |
b7b65b15 | 1743 | { |
bc5a45f3 | 1744 | /* Note that we don't need to consider the case where the |
5930fe97 EZ |
1745 | prev character has its type overridden by an RLO or LRO, |
1746 | because then either the type of this NSM would have been | |
1747 | also overridden, or the previous character is outside the | |
1748 | current level run, and thus not relevant to this NSM. | |
1749 | This is why NSM gets the type_after_w1 of the previous | |
1750 | character. */ | |
ebb5722e EZ |
1751 | if (bidi_it->prev.type_after_w1 != UNKNOWN_BT |
1752 | /* if type_after_w1 is NEUTRAL_B, this NSM is at sor */ | |
1753 | && bidi_it->prev.type_after_w1 != NEUTRAL_B) | |
5930fe97 | 1754 | type = bidi_it->prev.type_after_w1; |
bc5a45f3 EZ |
1755 | else if (bidi_it->sor == R2L) |
1756 | type = STRONG_R; | |
1757 | else if (bidi_it->sor == L2R) | |
1758 | type = STRONG_L; | |
1759 | else /* shouldn't happen! */ | |
1088b922 | 1760 | emacs_abort (); |
b7b65b15 | 1761 | } |
bc5a45f3 EZ |
1762 | if (type == WEAK_EN /* W2 */ |
1763 | && bidi_it->last_strong.type_after_w1 == STRONG_AL) | |
1764 | type = WEAK_AN; | |
1765 | else if (type == STRONG_AL) /* W3 */ | |
1766 | type = STRONG_R; | |
1767 | else if ((type == WEAK_ES /* W4 */ | |
1768 | && bidi_it->prev.type_after_w1 == WEAK_EN | |
1769 | && bidi_it->prev.orig_type == WEAK_EN) | |
1770 | || (type == WEAK_CS | |
1771 | && ((bidi_it->prev.type_after_w1 == WEAK_EN | |
1772 | && bidi_it->prev.orig_type == WEAK_EN) | |
1773 | || bidi_it->prev.type_after_w1 == WEAK_AN))) | |
b7b65b15 | 1774 | { |
512a289d RS |
1775 | const unsigned char *s |
1776 | = (STRINGP (bidi_it->string.lstring) | |
1777 | ? SDATA (bidi_it->string.lstring) | |
1778 | : bidi_it->string.s); | |
1779 | ||
1780 | next_char = (bidi_it->charpos + bidi_it->nchars >= eob | |
1781 | ? BIDI_EOB | |
1782 | : bidi_char_at_pos (bidi_it->bytepos + bidi_it->ch_len, | |
1783 | s, bidi_it->string.unibyte)); | |
6bff6497 | 1784 | type_of_next = bidi_get_type (next_char, override); |
b7b65b15 | 1785 | |
bc5a45f3 | 1786 | if (type_of_next == WEAK_BN |
b7b65b15 EZ |
1787 | || bidi_explicit_dir_char (next_char)) |
1788 | { | |
1789 | bidi_copy_it (&saved_it, bidi_it); | |
1790 | while (bidi_resolve_explicit (bidi_it) == new_level | |
bc5a45f3 | 1791 | && bidi_it->type == WEAK_BN) |
b7b65b15 EZ |
1792 | ; |
1793 | type_of_next = bidi_it->type; | |
b7b65b15 EZ |
1794 | bidi_copy_it (bidi_it, &saved_it); |
1795 | } | |
bc5a45f3 EZ |
1796 | |
1797 | /* If the next character is EN, but the last strong-type | |
1798 | character is AL, that next EN will be changed to AN when | |
1799 | we process it in W2 above. So in that case, this ES | |
1800 | should not be changed into EN. */ | |
1801 | if (type == WEAK_ES | |
1802 | && type_of_next == WEAK_EN | |
1803 | && bidi_it->last_strong.type_after_w1 != STRONG_AL) | |
1804 | type = WEAK_EN; | |
1805 | else if (type == WEAK_CS) | |
b7b65b15 | 1806 | { |
bc5a45f3 EZ |
1807 | if (bidi_it->prev.type_after_w1 == WEAK_AN |
1808 | && (type_of_next == WEAK_AN | |
1809 | /* If the next character is EN, but the last | |
1810 | strong-type character is AL, EN will be later | |
1811 | changed to AN when we process it in W2 above. | |
1812 | So in that case, this ES should not be | |
1813 | changed into EN. */ | |
1814 | || (type_of_next == WEAK_EN | |
1815 | && bidi_it->last_strong.type_after_w1 == STRONG_AL))) | |
1816 | type = WEAK_AN; | |
1817 | else if (bidi_it->prev.type_after_w1 == WEAK_EN | |
1818 | && type_of_next == WEAK_EN | |
1819 | && bidi_it->last_strong.type_after_w1 != STRONG_AL) | |
1820 | type = WEAK_EN; | |
1821 | } | |
1822 | } | |
1823 | else if (type == WEAK_ET /* W5: ET with EN before or after it */ | |
1824 | || type == WEAK_BN) /* W5/Retaining */ | |
1825 | { | |
7b5d6677 | 1826 | if (bidi_it->prev.type_after_w1 == WEAK_EN) /* ET/BN w/EN before it */ |
bc5a45f3 | 1827 | type = WEAK_EN; |
7b5d6677 EZ |
1828 | else if (bidi_it->next_en_pos > bidi_it->charpos |
1829 | && bidi_it->next_en_type != WEAK_BN) | |
1830 | { | |
1831 | if (bidi_it->next_en_type == WEAK_EN) /* ET/BN with EN after it */ | |
1832 | type = WEAK_EN; | |
1833 | } | |
1834 | else if (bidi_it->next_en_pos >=0) | |
bc5a45f3 | 1835 | { |
d311d28c | 1836 | ptrdiff_t en_pos = bidi_it->charpos + bidi_it->nchars; |
512a289d RS |
1837 | const unsigned char *s = (STRINGP (bidi_it->string.lstring) |
1838 | ? SDATA (bidi_it->string.lstring) | |
1839 | : bidi_it->string.s); | |
bc5a45f3 | 1840 | |
102ebb00 | 1841 | if (bidi_it->nchars <= 0) |
1088b922 | 1842 | emacs_abort (); |
512a289d RS |
1843 | next_char |
1844 | = (bidi_it->charpos + bidi_it->nchars >= eob | |
1845 | ? BIDI_EOB | |
1846 | : bidi_char_at_pos (bidi_it->bytepos + bidi_it->ch_len, s, | |
1847 | bidi_it->string.unibyte)); | |
bc5a45f3 EZ |
1848 | type_of_next = bidi_get_type (next_char, override); |
1849 | ||
1850 | if (type_of_next == WEAK_ET | |
1851 | || type_of_next == WEAK_BN | |
1852 | || bidi_explicit_dir_char (next_char)) | |
1853 | { | |
1854 | bidi_copy_it (&saved_it, bidi_it); | |
1855 | while (bidi_resolve_explicit (bidi_it) == new_level | |
1856 | && (bidi_it->type == WEAK_BN | |
1857 | || bidi_it->type == WEAK_ET)) | |
1858 | ; | |
1859 | type_of_next = bidi_it->type; | |
1860 | en_pos = bidi_it->charpos; | |
1861 | bidi_copy_it (bidi_it, &saved_it); | |
1862 | } | |
7b5d6677 EZ |
1863 | /* Remember this position, to speed up processing of the |
1864 | next ETs. */ | |
1865 | bidi_it->next_en_pos = en_pos; | |
bc5a45f3 | 1866 | if (type_of_next == WEAK_EN) |
b7b65b15 | 1867 | { |
bc5a45f3 EZ |
1868 | /* If the last strong character is AL, the EN we've |
1869 | found will become AN when we get to it (W2). */ | |
7b5d6677 EZ |
1870 | if (bidi_it->last_strong.type_after_w1 == STRONG_AL) |
1871 | type_of_next = WEAK_AN; | |
bc5a45f3 EZ |
1872 | else if (type == WEAK_BN) |
1873 | type = NEUTRAL_ON; /* W6/Retaining */ | |
7b5d6677 EZ |
1874 | else |
1875 | type = WEAK_EN; | |
b7b65b15 | 1876 | } |
4787455f EZ |
1877 | else if (type_of_next == NEUTRAL_B) |
1878 | /* Record the fact that there are no more ENs from | |
1879 | here to the end of paragraph, to avoid entering the | |
1880 | loop above ever again in this paragraph. */ | |
1881 | bidi_it->next_en_pos = -1; | |
7b5d6677 EZ |
1882 | /* Record the type of the character where we ended our search. */ |
1883 | bidi_it->next_en_type = type_of_next; | |
b7b65b15 EZ |
1884 | } |
1885 | } | |
1886 | } | |
1887 | ||
1888 | if (type == WEAK_ES || type == WEAK_ET || type == WEAK_CS /* W6 */ | |
89d3374a EZ |
1889 | || (type == WEAK_BN |
1890 | && (bidi_it->prev.type_after_w1 == WEAK_CS /* W6/Retaining */ | |
1891 | || bidi_it->prev.type_after_w1 == WEAK_ES | |
1892 | || bidi_it->prev.type_after_w1 == WEAK_ET))) | |
b7b65b15 EZ |
1893 | type = NEUTRAL_ON; |
1894 | ||
1895 | /* Store the type we've got so far, before we clobber it with strong | |
1896 | types in W7 and while resolving neutral types. But leave alone | |
1897 | the original types that were recorded above, because we will need | |
1898 | them for the L1 clause. */ | |
89d3374a EZ |
1899 | if (bidi_it->type_after_w1 == UNKNOWN_BT) |
1900 | bidi_it->type_after_w1 = type; | |
1901 | bidi_check_type (bidi_it->type_after_w1); | |
b7b65b15 EZ |
1902 | |
1903 | if (type == WEAK_EN) /* W7 */ | |
1904 | { | |
89d3374a | 1905 | if ((bidi_it->last_strong.type_after_w1 == STRONG_L) |
b7b65b15 EZ |
1906 | || (bidi_it->last_strong.type == UNKNOWN_BT && bidi_it->sor == L2R)) |
1907 | type = STRONG_L; | |
1908 | } | |
1909 | ||
1910 | bidi_it->type = type; | |
2d6e4628 | 1911 | bidi_check_type (bidi_it->type); |
b7b65b15 EZ |
1912 | return type; |
1913 | } | |
1914 | ||
cbb09f04 EZ |
1915 | /* Resolve the type of a neutral character according to the type of |
1916 | surrounding strong text and the current embedding level. */ | |
0a99eee1 | 1917 | static bidi_type_t |
cbb09f04 EZ |
1918 | bidi_resolve_neutral_1 (bidi_type_t prev_type, bidi_type_t next_type, int lev) |
1919 | { | |
1920 | /* N1: European and Arabic numbers are treated as though they were R. */ | |
1921 | if (next_type == WEAK_EN || next_type == WEAK_AN) | |
1922 | next_type = STRONG_R; | |
1923 | if (prev_type == WEAK_EN || prev_type == WEAK_AN) | |
1924 | prev_type = STRONG_R; | |
1925 | ||
1926 | if (next_type == prev_type) /* N1 */ | |
1927 | return next_type; | |
1928 | else if ((lev & 1) == 0) /* N2 */ | |
1929 | return STRONG_L; | |
1930 | else | |
1931 | return STRONG_R; | |
1932 | } | |
1933 | ||
fd3998ff | 1934 | static bidi_type_t |
b7b65b15 EZ |
1935 | bidi_resolve_neutral (struct bidi_it *bidi_it) |
1936 | { | |
1937 | int prev_level = bidi_it->level_stack[bidi_it->stack_idx].level; | |
1938 | bidi_type_t type = bidi_resolve_weak (bidi_it); | |
1939 | int current_level = bidi_it->level_stack[bidi_it->stack_idx].level; | |
1940 | ||
1941 | if (!(type == STRONG_R | |
1942 | || type == STRONG_L | |
1943 | || type == WEAK_BN | |
1944 | || type == WEAK_EN | |
1945 | || type == WEAK_AN | |
1946 | || type == NEUTRAL_B | |
1947 | || type == NEUTRAL_S | |
1948 | || type == NEUTRAL_WS | |
1949 | || type == NEUTRAL_ON)) | |
1088b922 | 1950 | emacs_abort (); |
b7b65b15 | 1951 | |
4787455f EZ |
1952 | if ((type != NEUTRAL_B /* Don't risk entering the long loop below if |
1953 | we are already at paragraph end. */ | |
1954 | && bidi_get_category (type) == NEUTRAL) | |
b7b65b15 EZ |
1955 | || (type == WEAK_BN && prev_level == current_level)) |
1956 | { | |
1957 | if (bidi_it->next_for_neutral.type != UNKNOWN_BT) | |
1958 | type = bidi_resolve_neutral_1 (bidi_it->prev_for_neutral.type, | |
1959 | bidi_it->next_for_neutral.type, | |
1960 | current_level); | |
4787455f EZ |
1961 | /* The next two "else if" clauses are shortcuts for the |
1962 | important special case when we have a long sequence of | |
1963 | neutral or WEAK_BN characters, such as whitespace or nulls or | |
1964 | other control characters, on the base embedding level of the | |
1965 | paragraph, and that sequence goes all the way to the end of | |
1966 | the paragraph and follows a character whose resolved | |
1967 | directionality is identical to the base embedding level. | |
1968 | (This is what happens in a buffer with plain L2R text that | |
1969 | happens to include long sequences of control characters.) By | |
1970 | virtue of N1, the result of examining this long sequence will | |
1971 | always be either STRONG_L or STRONG_R, depending on the base | |
1972 | embedding level. So we use this fact directly instead of | |
1973 | entering the expensive loop in the "else" clause. */ | |
1974 | else if (current_level == 0 | |
1975 | && bidi_it->prev_for_neutral.type == STRONG_L | |
1976 | && !bidi_explicit_dir_char (bidi_it->ch)) | |
1977 | type = bidi_resolve_neutral_1 (bidi_it->prev_for_neutral.type, | |
1978 | STRONG_L, current_level); | |
1979 | else if (/* current level is 1 */ | |
1980 | current_level == 1 | |
1981 | /* base embedding level is also 1 */ | |
1982 | && bidi_it->level_stack[0].level == 1 | |
1983 | /* previous character is one of those considered R for | |
1984 | the purposes of W5 */ | |
1985 | && (bidi_it->prev_for_neutral.type == STRONG_R | |
1986 | || bidi_it->prev_for_neutral.type == WEAK_EN | |
1987 | || bidi_it->prev_for_neutral.type == WEAK_AN) | |
1988 | && !bidi_explicit_dir_char (bidi_it->ch)) | |
1989 | type = bidi_resolve_neutral_1 (bidi_it->prev_for_neutral.type, | |
1990 | STRONG_R, current_level); | |
b7b65b15 EZ |
1991 | else |
1992 | { | |
1993 | /* Arrrgh!! The UAX#9 algorithm is too deeply entrenched in | |
1994 | the assumption of batch-style processing; see clauses W4, | |
1995 | W5, and especially N1, which require to look far forward | |
182ce2d2 EZ |
1996 | (as well as back) in the buffer/string. May the fleas of |
1997 | a thousand camels infest the armpits of those who design | |
b7b65b15 EZ |
1998 | supposedly general-purpose algorithms by looking at their |
1999 | own implementations, and fail to consider other possible | |
2000 | implementations! */ | |
2001 | struct bidi_it saved_it; | |
2002 | bidi_type_t next_type; | |
2003 | ||
2004 | if (bidi_it->scan_dir == -1) | |
1088b922 | 2005 | emacs_abort (); |
b7b65b15 EZ |
2006 | |
2007 | bidi_copy_it (&saved_it, bidi_it); | |
2008 | /* Scan the text forward until we find the first non-neutral | |
2009 | character, and then use that to resolve the neutral we | |
2010 | are dealing with now. We also cache the scanned iterator | |
2011 | states, to salvage some of the effort later. */ | |
2012 | bidi_cache_iterator_state (bidi_it, 0); | |
2013 | do { | |
2014 | /* Record the info about the previous character, so that | |
2015 | it will be cached below with this state. */ | |
89d3374a | 2016 | if (bidi_it->type_after_w1 != WEAK_BN /* W1/Retaining */ |
b7b65b15 EZ |
2017 | && bidi_it->type != WEAK_BN) |
2018 | bidi_remember_char (&bidi_it->prev, bidi_it); | |
2019 | type = bidi_resolve_weak (bidi_it); | |
2020 | /* Paragraph separators have their levels fully resolved | |
2021 | at this point, so cache them as resolved. */ | |
2022 | bidi_cache_iterator_state (bidi_it, type == NEUTRAL_B); | |
2023 | /* FIXME: implement L1 here, by testing for a newline and | |
2024 | resetting the level for any sequence of whitespace | |
2025 | characters adjacent to it. */ | |
2026 | } while (!(type == NEUTRAL_B | |
2027 | || (type != WEAK_BN | |
2028 | && bidi_get_category (type) != NEUTRAL) | |
2029 | /* This is all per level run, so stop when we | |
2030 | reach the end of this level run. */ | |
512a289d RS |
2031 | || (bidi_it->level_stack[bidi_it->stack_idx].level |
2032 | != current_level))); | |
b7b65b15 EZ |
2033 | |
2034 | bidi_remember_char (&saved_it.next_for_neutral, bidi_it); | |
2035 | ||
2036 | switch (type) | |
2037 | { | |
2038 | case STRONG_L: | |
2039 | case STRONG_R: | |
2040 | case STRONG_AL: | |
4787455f EZ |
2041 | /* Actually, STRONG_AL cannot happen here, because |
2042 | bidi_resolve_weak converts it to STRONG_R, per W3. */ | |
a54e2c05 | 2043 | eassert (type != STRONG_AL); |
b7b65b15 EZ |
2044 | next_type = type; |
2045 | break; | |
2046 | case WEAK_EN: | |
2047 | case WEAK_AN: | |
2048 | /* N1: ``European and Arabic numbers are treated as | |
2049 | though they were R.'' */ | |
2050 | next_type = STRONG_R; | |
b7b65b15 EZ |
2051 | break; |
2052 | case WEAK_BN: | |
713bfeaa | 2053 | case NEUTRAL_ON: /* W6/Retaining */ |
b7b65b15 | 2054 | if (!bidi_explicit_dir_char (bidi_it->ch)) |
1088b922 | 2055 | emacs_abort (); /* can't happen: BNs are skipped */ |
b7b65b15 EZ |
2056 | /* FALLTHROUGH */ |
2057 | case NEUTRAL_B: | |
2058 | /* Marched all the way to the end of this level run. | |
2059 | We need to use the eor type, whose information is | |
2060 | stored by bidi_set_sor_type in the prev_for_neutral | |
2061 | member. */ | |
2062 | if (saved_it.type != WEAK_BN | |
89d3374a | 2063 | || bidi_get_category (bidi_it->prev.type_after_w1) == NEUTRAL) |
4787455f | 2064 | next_type = bidi_it->prev_for_neutral.type; |
b7b65b15 EZ |
2065 | else |
2066 | { | |
2067 | /* This is a BN which does not adjoin neutrals. | |
2068 | Leave its type alone. */ | |
2069 | bidi_copy_it (bidi_it, &saved_it); | |
2070 | return bidi_it->type; | |
2071 | } | |
2072 | break; | |
2073 | default: | |
1088b922 | 2074 | emacs_abort (); |
b7b65b15 EZ |
2075 | } |
2076 | type = bidi_resolve_neutral_1 (saved_it.prev_for_neutral.type, | |
2077 | next_type, current_level); | |
4787455f | 2078 | saved_it.next_for_neutral.type = next_type; |
b7b65b15 | 2079 | saved_it.type = type; |
4787455f | 2080 | bidi_check_type (next_type); |
2d6e4628 | 2081 | bidi_check_type (type); |
b7b65b15 EZ |
2082 | bidi_copy_it (bidi_it, &saved_it); |
2083 | } | |
2084 | } | |
2085 | return type; | |
2086 | } | |
2087 | ||
2088 | /* Given an iterator state in BIDI_IT, advance one character position | |
182ce2d2 EZ |
2089 | in the buffer/string to the next character (in the logical order), |
2090 | resolve the bidi type of that next character, and return that | |
2091 | type. */ | |
fd3998ff | 2092 | static bidi_type_t |
b7b65b15 EZ |
2093 | bidi_type_of_next_char (struct bidi_it *bidi_it) |
2094 | { | |
2095 | bidi_type_t type; | |
2096 | ||
2097 | /* This should always be called during a forward scan. */ | |
2098 | if (bidi_it->scan_dir != 1) | |
1088b922 | 2099 | emacs_abort (); |
b7b65b15 EZ |
2100 | |
2101 | /* Reset the limit until which to ignore BNs if we step out of the | |
2102 | area where we found only empty levels. */ | |
87e67904 | 2103 | if ((bidi_it->ignore_bn_limit > -1 |
b7b65b15 | 2104 | && bidi_it->ignore_bn_limit <= bidi_it->charpos) |
87e67904 | 2105 | || (bidi_it->ignore_bn_limit == -2 |
b7b65b15 | 2106 | && !bidi_explicit_dir_char (bidi_it->ch))) |
87e67904 | 2107 | bidi_it->ignore_bn_limit = -1; |
b7b65b15 EZ |
2108 | |
2109 | type = bidi_resolve_neutral (bidi_it); | |
2110 | ||
2111 | return type; | |
2112 | } | |
2113 | ||
2114 | /* Given an iterator state BIDI_IT, advance one character position in | |
182ce2d2 EZ |
2115 | the buffer/string to the next character (in the current scan |
2116 | direction), resolve the embedding and implicit levels of that next | |
2117 | character, and return the resulting level. */ | |
fd3998ff | 2118 | static int |
b7b65b15 EZ |
2119 | bidi_level_of_next_char (struct bidi_it *bidi_it) |
2120 | { | |
2121 | bidi_type_t type; | |
2122 | int level, prev_level = -1; | |
2123 | struct bidi_saved_info next_for_neutral; | |
d311d28c | 2124 | ptrdiff_t next_char_pos = -2; |
b7b65b15 EZ |
2125 | |
2126 | if (bidi_it->scan_dir == 1) | |
2127 | { | |
5895d7b9 | 2128 | ptrdiff_t eob |
512a289d RS |
2129 | = ((bidi_it->string.s || STRINGP (bidi_it->string.lstring)) |
2130 | ? bidi_it->string.schars : ZV); | |
9f257352 | 2131 | |
b7b65b15 | 2132 | /* There's no sense in trying to advance if we hit end of text. */ |
9f257352 | 2133 | if (bidi_it->charpos >= eob) |
b7b65b15 EZ |
2134 | return bidi_it->resolved_level; |
2135 | ||
2136 | /* Record the info about the previous character. */ | |
89d3374a | 2137 | if (bidi_it->type_after_w1 != WEAK_BN /* W1/Retaining */ |
b7b65b15 EZ |
2138 | && bidi_it->type != WEAK_BN) |
2139 | bidi_remember_char (&bidi_it->prev, bidi_it); | |
89d3374a EZ |
2140 | if (bidi_it->type_after_w1 == STRONG_R |
2141 | || bidi_it->type_after_w1 == STRONG_L | |
2142 | || bidi_it->type_after_w1 == STRONG_AL) | |
b7b65b15 EZ |
2143 | bidi_remember_char (&bidi_it->last_strong, bidi_it); |
2144 | /* FIXME: it sounds like we don't need both prev and | |
2145 | prev_for_neutral members, but I'm leaving them both for now. */ | |
2146 | if (bidi_it->type == STRONG_R || bidi_it->type == STRONG_L | |
2147 | || bidi_it->type == WEAK_EN || bidi_it->type == WEAK_AN) | |
2148 | bidi_remember_char (&bidi_it->prev_for_neutral, bidi_it); | |
2149 | ||
2150 | /* If we overstepped the characters used for resolving neutrals | |
2151 | and whitespace, invalidate their info in the iterator. */ | |
2152 | if (bidi_it->charpos >= bidi_it->next_for_neutral.charpos) | |
2153 | bidi_it->next_for_neutral.type = UNKNOWN_BT; | |
2154 | if (bidi_it->next_en_pos >= 0 | |
2155 | && bidi_it->charpos >= bidi_it->next_en_pos) | |
7b5d6677 EZ |
2156 | { |
2157 | bidi_it->next_en_pos = 0; | |
2158 | bidi_it->next_en_type = UNKNOWN_BT; | |
2159 | } | |
b7b65b15 EZ |
2160 | if (bidi_it->next_for_ws.type != UNKNOWN_BT |
2161 | && bidi_it->charpos >= bidi_it->next_for_ws.charpos) | |
2162 | bidi_it->next_for_ws.type = UNKNOWN_BT; | |
2163 | ||
2164 | /* This must be taken before we fill the iterator with the info | |
2165 | about the next char. If we scan backwards, the iterator | |
2166 | state must be already cached, so there's no need to know the | |
2167 | embedding level of the previous character, since we will be | |
2168 | returning to our caller shortly. */ | |
2169 | prev_level = bidi_it->level_stack[bidi_it->stack_idx].level; | |
2170 | } | |
2171 | next_for_neutral = bidi_it->next_for_neutral; | |
2172 | ||
182ce2d2 EZ |
2173 | /* Perhaps the character we want is already cached. If it is, the |
2174 | call to bidi_cache_find below will return a type other than | |
2175 | UNKNOWN_BT. */ | |
87e67904 | 2176 | if (bidi_cache_idx > bidi_cache_start && !bidi_it->first_elt) |
102ebb00 | 2177 | { |
512a289d RS |
2178 | int bob = ((bidi_it->string.s || STRINGP (bidi_it->string.lstring)) |
2179 | ? 0 : 1); | |
102ebb00 EZ |
2180 | if (bidi_it->scan_dir > 0) |
2181 | { | |
2182 | if (bidi_it->nchars <= 0) | |
1088b922 | 2183 | emacs_abort (); |
102ebb00 EZ |
2184 | next_char_pos = bidi_it->charpos + bidi_it->nchars; |
2185 | } | |
9f257352 | 2186 | else if (bidi_it->charpos >= bob) |
bb269206 EZ |
2187 | /* Implementation note: we allow next_char_pos to be as low as |
2188 | 0 for buffers or -1 for strings, and that is okay because | |
2189 | that's the "position" of the sentinel iterator state we | |
2190 | cached at the beginning of the iteration. */ | |
102ebb00 | 2191 | next_char_pos = bidi_it->charpos - 1; |
578b494e | 2192 | if (next_char_pos >= bob - 1) |
87e67904 EZ |
2193 | type = bidi_cache_find (next_char_pos, -1, bidi_it); |
2194 | else | |
2195 | type = UNKNOWN_BT; | |
102ebb00 | 2196 | } |
182ce2d2 | 2197 | else |
102ebb00 | 2198 | type = UNKNOWN_BT; |
b7b65b15 EZ |
2199 | if (type != UNKNOWN_BT) |
2200 | { | |
2201 | /* Don't lose the information for resolving neutrals! The | |
2202 | cached states could have been cached before their | |
2203 | next_for_neutral member was computed. If we are on our way | |
2204 | forward, we can simply take the info from the previous | |
2205 | state. */ | |
2206 | if (bidi_it->scan_dir == 1 | |
2207 | && bidi_it->next_for_neutral.type == UNKNOWN_BT) | |
2208 | bidi_it->next_for_neutral = next_for_neutral; | |
2209 | ||
2210 | /* If resolved_level is -1, it means this state was cached | |
2211 | before it was completely resolved, so we cannot return | |
2212 | it. */ | |
2213 | if (bidi_it->resolved_level != -1) | |
2214 | return bidi_it->resolved_level; | |
2215 | } | |
2216 | if (bidi_it->scan_dir == -1) | |
2217 | /* If we are going backwards, the iterator state is already cached | |
2218 | from previous scans, and should be fully resolved. */ | |
1088b922 | 2219 | emacs_abort (); |
b7b65b15 EZ |
2220 | |
2221 | if (type == UNKNOWN_BT) | |
2222 | type = bidi_type_of_next_char (bidi_it); | |
2223 | ||
2224 | if (type == NEUTRAL_B) | |
2225 | return bidi_it->resolved_level; | |
2226 | ||
2227 | level = bidi_it->level_stack[bidi_it->stack_idx].level; | |
2228 | if ((bidi_get_category (type) == NEUTRAL /* && type != NEUTRAL_B */) | |
2229 | || (type == WEAK_BN && prev_level == level)) | |
2230 | { | |
2231 | if (bidi_it->next_for_neutral.type == UNKNOWN_BT) | |
1088b922 | 2232 | emacs_abort (); |
b7b65b15 EZ |
2233 | |
2234 | /* If the cached state shows a neutral character, it was not | |
2235 | resolved by bidi_resolve_neutral, so do it now. */ | |
2236 | type = bidi_resolve_neutral_1 (bidi_it->prev_for_neutral.type, | |
2237 | bidi_it->next_for_neutral.type, | |
2238 | level); | |
2239 | } | |
2240 | ||
2241 | if (!(type == STRONG_R | |
2242 | || type == STRONG_L | |
2243 | || type == WEAK_BN | |
2244 | || type == WEAK_EN | |
2245 | || type == WEAK_AN)) | |
1088b922 | 2246 | emacs_abort (); |
b7b65b15 | 2247 | bidi_it->type = type; |
2d6e4628 | 2248 | bidi_check_type (bidi_it->type); |
b7b65b15 EZ |
2249 | |
2250 | /* For L1 below, we need to know, for each WS character, whether | |
0d327994 | 2251 | it belongs to a sequence of WS characters preceding a newline |
b7b65b15 | 2252 | or a TAB or a paragraph separator. */ |
89d3374a | 2253 | if (bidi_it->orig_type == NEUTRAL_WS |
b7b65b15 EZ |
2254 | && bidi_it->next_for_ws.type == UNKNOWN_BT) |
2255 | { | |
2256 | int ch; | |
d311d28c PE |
2257 | ptrdiff_t clen = bidi_it->ch_len; |
2258 | ptrdiff_t bpos = bidi_it->bytepos; | |
2259 | ptrdiff_t cpos = bidi_it->charpos; | |
2260 | ptrdiff_t disp_pos = bidi_it->disp_pos; | |
2261 | ptrdiff_t nc = bidi_it->nchars; | |
87e67904 | 2262 | struct bidi_string_data bs = bidi_it->string; |
b7b65b15 | 2263 | bidi_type_t chtype; |
2cc21167 | 2264 | bool fwp = bidi_it->frame_window_p; |
0c95fcf7 | 2265 | int dpp = bidi_it->disp_prop; |
b7b65b15 | 2266 | |
102ebb00 | 2267 | if (bidi_it->nchars <= 0) |
1088b922 | 2268 | emacs_abort (); |
b7b65b15 | 2269 | do { |
36075a19 | 2270 | ch = bidi_fetch_char (cpos += nc, bpos += clen, &disp_pos, &dpp, &bs, |
5bf97bfc | 2271 | bidi_it->w, fwp, &clen, &nc); |
79beb178 | 2272 | if (ch == '\n' || ch == BIDI_EOB) |
b7b65b15 EZ |
2273 | chtype = NEUTRAL_B; |
2274 | else | |
6bff6497 | 2275 | chtype = bidi_get_type (ch, NEUTRAL_DIR); |
b7b65b15 EZ |
2276 | } while (chtype == NEUTRAL_WS || chtype == WEAK_BN |
2277 | || bidi_explicit_dir_char (ch)); /* L1/Retaining */ | |
2278 | bidi_it->next_for_ws.type = chtype; | |
2d6e4628 | 2279 | bidi_check_type (bidi_it->next_for_ws.type); |
b7b65b15 EZ |
2280 | bidi_it->next_for_ws.charpos = cpos; |
2281 | bidi_it->next_for_ws.bytepos = bpos; | |
2282 | } | |
2283 | ||
2284 | /* Resolve implicit levels, with a twist: PDFs get the embedding | |
55622b93 | 2285 | level of the embedding they terminate. See below for the |
b7b65b15 | 2286 | reason. */ |
89d3374a | 2287 | if (bidi_it->orig_type == PDF |
b7b65b15 EZ |
2288 | /* Don't do this if this formatting code didn't change the |
2289 | embedding level due to invalid or empty embeddings. */ | |
2290 | && prev_level != level) | |
2291 | { | |
2292 | /* Don't look in UAX#9 for the reason for this: it's our own | |
2293 | private quirk. The reason is that we want the formatting | |
2294 | codes to be delivered so that they bracket the text of their | |
2295 | embedding. For example, given the text | |
2296 | ||
2297 | {RLO}teST{PDF} | |
2298 | ||
2299 | we want it to be displayed as | |
2300 | ||
0d68907d | 2301 | {PDF}STet{RLO} |
b7b65b15 EZ |
2302 | |
2303 | not as | |
2304 | ||
2305 | STet{RLO}{PDF} | |
2306 | ||
2307 | which will result because we bump up the embedding level as | |
2308 | soon as we see the RLO and pop it as soon as we see the PDF, | |
2309 | so RLO itself has the same embedding level as "teST", and | |
2310 | thus would be normally delivered last, just before the PDF. | |
2311 | The switch below fiddles with the level of PDF so that this | |
2312 | ugly side effect does not happen. | |
2313 | ||
2314 | (This is, of course, only important if the formatting codes | |
e7402cb2 EZ |
2315 | are actually displayed, but Emacs does need to display them |
2316 | if the user wants to.) */ | |
b7b65b15 EZ |
2317 | level = prev_level; |
2318 | } | |
89d3374a EZ |
2319 | else if (bidi_it->orig_type == NEUTRAL_B /* L1 */ |
2320 | || bidi_it->orig_type == NEUTRAL_S | |
e7402cb2 | 2321 | || bidi_it->ch == '\n' || bidi_it->ch == BIDI_EOB |
89d3374a | 2322 | || (bidi_it->orig_type == NEUTRAL_WS |
b7b65b15 EZ |
2323 | && (bidi_it->next_for_ws.type == NEUTRAL_B |
2324 | || bidi_it->next_for_ws.type == NEUTRAL_S))) | |
2325 | level = bidi_it->level_stack[0].level; | |
2326 | else if ((level & 1) == 0) /* I1 */ | |
2327 | { | |
2328 | if (type == STRONG_R) | |
2329 | level++; | |
2330 | else if (type == WEAK_EN || type == WEAK_AN) | |
2331 | level += 2; | |
2332 | } | |
2333 | else /* I2 */ | |
2334 | { | |
2335 | if (type == STRONG_L || type == WEAK_EN || type == WEAK_AN) | |
2336 | level++; | |
2337 | } | |
2338 | ||
2339 | bidi_it->resolved_level = level; | |
2340 | return level; | |
2341 | } | |
2342 | ||
2cc21167 PE |
2343 | /* Move to the other edge of a level given by LEVEL. If END_FLAG, |
2344 | we are at the end of a level, and we need to prepare to | |
b7b65b15 EZ |
2345 | resume the scan of the lower level. |
2346 | ||
2347 | If this level's other edge is cached, we simply jump to it, filling | |
2348 | the iterator structure with the iterator state on the other edge. | |
182ce2d2 EZ |
2349 | Otherwise, we walk the buffer or string until we come back to the |
2350 | same level as LEVEL. | |
b7b65b15 EZ |
2351 | |
2352 | Note: we are not talking here about a ``level run'' in the UAX#9 | |
2353 | sense of the term, but rather about a ``level'' which includes | |
2354 | all the levels higher than it. In other words, given the levels | |
2355 | like this: | |
2356 | ||
2357 | 11111112222222333333334443343222222111111112223322111 | |
2358 | A B C | |
2359 | ||
2360 | and assuming we are at point A scanning left to right, this | |
2361 | function moves to point C, whereas the UAX#9 ``level 2 run'' ends | |
2362 | at point B. */ | |
2363 | static void | |
2cc21167 | 2364 | bidi_find_other_level_edge (struct bidi_it *bidi_it, int level, bool end_flag) |
b7b65b15 EZ |
2365 | { |
2366 | int dir = end_flag ? -bidi_it->scan_dir : bidi_it->scan_dir; | |
39e378da | 2367 | ptrdiff_t idx; |
b7b65b15 EZ |
2368 | |
2369 | /* Try the cache first. */ | |
87e67904 EZ |
2370 | if ((idx = bidi_cache_find_level_change (level, dir, end_flag)) |
2371 | >= bidi_cache_start) | |
b7b65b15 EZ |
2372 | bidi_cache_fetch_state (idx, bidi_it); |
2373 | else | |
2374 | { | |
2375 | int new_level; | |
2376 | ||
1088b922 | 2377 | /* If we are at end of level, its edges must be cached. */ |
b7b65b15 | 2378 | if (end_flag) |
1088b922 | 2379 | emacs_abort (); |
b7b65b15 EZ |
2380 | |
2381 | bidi_cache_iterator_state (bidi_it, 1); | |
2382 | do { | |
2383 | new_level = bidi_level_of_next_char (bidi_it); | |
2384 | bidi_cache_iterator_state (bidi_it, 1); | |
2385 | } while (new_level >= level); | |
2386 | } | |
2387 | } | |
2388 | ||
2389 | void | |
4b292a22 | 2390 | bidi_move_to_visually_next (struct bidi_it *bidi_it) |
b7b65b15 EZ |
2391 | { |
2392 | int old_level, new_level, next_level; | |
9c82e145 | 2393 | struct bidi_it sentinel; |
acb28818 | 2394 | struct gcpro gcpro1; |
b7b65b15 | 2395 | |
87e67904 | 2396 | if (bidi_it->charpos < 0 || bidi_it->bytepos < 0) |
1088b922 | 2397 | emacs_abort (); |
b7b65b15 EZ |
2398 | |
2399 | if (bidi_it->scan_dir == 0) | |
2400 | { | |
2401 | bidi_it->scan_dir = 1; /* default to logical order */ | |
2402 | } | |
2403 | ||
acb28818 | 2404 | /* The code below can call eval, and thus cause GC. If we are |
7e2ad32c | 2405 | iterating a Lisp string, make sure it won't be GCed. */ |
acb28818 EZ |
2406 | if (STRINGP (bidi_it->string.lstring)) |
2407 | GCPRO1 (bidi_it->string.lstring); | |
2408 | ||
be39f003 | 2409 | /* If we just passed a newline, initialize for the next line. */ |
1137e8b8 EZ |
2410 | if (!bidi_it->first_elt |
2411 | && (bidi_it->ch == '\n' || bidi_it->ch == BIDI_EOB)) | |
be39f003 EZ |
2412 | bidi_line_init (bidi_it); |
2413 | ||
6dcfd253 EZ |
2414 | /* Prepare the sentinel iterator state, and cache it. When we bump |
2415 | into it, scanning backwards, we'll know that the last non-base | |
2416 | level is exhausted. */ | |
87e67904 | 2417 | if (bidi_cache_idx == bidi_cache_start) |
9c82e145 EZ |
2418 | { |
2419 | bidi_copy_it (&sentinel, bidi_it); | |
2420 | if (bidi_it->first_elt) | |
2421 | { | |
2422 | sentinel.charpos--; /* cached charpos needs to be monotonic */ | |
2423 | sentinel.bytepos--; | |
2424 | sentinel.ch = '\n'; /* doesn't matter, but why not? */ | |
2425 | sentinel.ch_len = 1; | |
182ce2d2 | 2426 | sentinel.nchars = 1; |
9c82e145 | 2427 | } |
6dcfd253 | 2428 | bidi_cache_iterator_state (&sentinel, 1); |
9c82e145 | 2429 | } |
b7b65b15 EZ |
2430 | |
2431 | old_level = bidi_it->resolved_level; | |
2432 | new_level = bidi_level_of_next_char (bidi_it); | |
b7b65b15 EZ |
2433 | |
2434 | /* Reordering of resolved levels (clause L2) is implemented by | |
2435 | jumping to the other edge of the level and flipping direction of | |
c0546589 | 2436 | scanning the text whenever we find a level change. */ |
b7b65b15 EZ |
2437 | if (new_level != old_level) |
2438 | { | |
2cc21167 | 2439 | bool ascending = new_level > old_level; |
b7b65b15 EZ |
2440 | int level_to_search = ascending ? old_level + 1 : old_level; |
2441 | int incr = ascending ? 1 : -1; | |
2442 | int expected_next_level = old_level + incr; | |
2443 | ||
b7b65b15 EZ |
2444 | /* Jump (or walk) to the other edge of this level. */ |
2445 | bidi_find_other_level_edge (bidi_it, level_to_search, !ascending); | |
2446 | /* Switch scan direction and peek at the next character in the | |
2447 | new direction. */ | |
2448 | bidi_it->scan_dir = -bidi_it->scan_dir; | |
2449 | ||
2450 | /* The following loop handles the case where the resolved level | |
2451 | jumps by more than one. This is typical for numbers inside a | |
2452 | run of text with left-to-right embedding direction, but can | |
2453 | also happen in other situations. In those cases the decision | |
2454 | where to continue after a level change, and in what direction, | |
2455 | is tricky. For example, given a text like below: | |
2456 | ||
2457 | abcdefgh | |
2458 | 11336622 | |
2459 | ||
2460 | (where the numbers below the text show the resolved levels), | |
2461 | the result of reordering according to UAX#9 should be this: | |
2462 | ||
2463 | efdcghba | |
2464 | ||
2465 | This is implemented by the loop below which flips direction | |
2466 | and jumps to the other edge of the level each time it finds | |
2467 | the new level not to be the expected one. The expected level | |
2468 | is always one more or one less than the previous one. */ | |
2469 | next_level = bidi_peek_at_next_level (bidi_it); | |
2470 | while (next_level != expected_next_level) | |
2471 | { | |
713bfeaa EZ |
2472 | /* If next_level is -1, it means we have an unresolved level |
2473 | in the cache, which at this point should not happen. If | |
2474 | it does, we will infloop. */ | |
2475 | eassert (next_level >= 0); | |
b7b65b15 EZ |
2476 | expected_next_level += incr; |
2477 | level_to_search += incr; | |
2478 | bidi_find_other_level_edge (bidi_it, level_to_search, !ascending); | |
2479 | bidi_it->scan_dir = -bidi_it->scan_dir; | |
2480 | next_level = bidi_peek_at_next_level (bidi_it); | |
2481 | } | |
2482 | ||
2483 | /* Finally, deliver the next character in the new direction. */ | |
2484 | next_level = bidi_level_of_next_char (bidi_it); | |
2485 | } | |
2486 | ||
b44d9321 EZ |
2487 | /* Take note when we have just processed the newline that precedes |
2488 | the end of the paragraph. The next time we are about to be | |
2489 | called, set_iterator_to_next will automatically reinit the | |
2490 | paragraph direction, if needed. We do this at the newline before | |
2491 | the paragraph separator, because the next character might not be | |
2492 | the first character of the next paragraph, due to the bidi | |
c0546589 EZ |
2493 | reordering, whereas we _must_ know the paragraph base direction |
2494 | _before_ we process the paragraph's text, since the base | |
2495 | direction affects the reordering. */ | |
1137e8b8 EZ |
2496 | if (bidi_it->scan_dir == 1 |
2497 | && (bidi_it->ch == '\n' || bidi_it->ch == BIDI_EOB)) | |
be39f003 | 2498 | { |
87e67904 EZ |
2499 | /* The paragraph direction of the entire string, once |
2500 | determined, is in effect for the entire string. Setting the | |
2501 | separator limit to the end of the string prevents | |
2502 | bidi_paragraph_init from being called automatically on this | |
2503 | string. */ | |
9f257352 | 2504 | if (bidi_it->string.s || STRINGP (bidi_it->string.lstring)) |
87e67904 EZ |
2505 | bidi_it->separator_limit = bidi_it->string.schars; |
2506 | else if (bidi_it->bytepos < ZV_BYTE) | |
be39f003 | 2507 | { |
5895d7b9 | 2508 | ptrdiff_t sep_len |
512a289d RS |
2509 | = bidi_at_paragraph_end (bidi_it->charpos + bidi_it->nchars, |
2510 | bidi_it->bytepos + bidi_it->ch_len); | |
87e67904 | 2511 | if (bidi_it->nchars <= 0) |
1088b922 | 2512 | emacs_abort (); |
87e67904 EZ |
2513 | if (sep_len >= 0) |
2514 | { | |
2515 | bidi_it->new_paragraph = 1; | |
2516 | /* Record the buffer position of the last character of the | |
2517 | paragraph separator. */ | |
512a289d RS |
2518 | bidi_it->separator_limit |
2519 | = bidi_it->charpos + bidi_it->nchars + sep_len; | |
87e67904 | 2520 | } |
be39f003 EZ |
2521 | } |
2522 | } | |
6bff6497 | 2523 | |
87e67904 | 2524 | if (bidi_it->scan_dir == 1 && bidi_cache_idx > bidi_cache_start) |
b7b65b15 EZ |
2525 | { |
2526 | /* If we are at paragraph's base embedding level and beyond the | |
2527 | last cached position, the cache's job is done and we can | |
2528 | discard it. */ | |
2529 | if (bidi_it->resolved_level == bidi_it->level_stack[0].level | |
182ce2d2 EZ |
2530 | && bidi_it->charpos > (bidi_cache[bidi_cache_idx - 1].charpos |
2531 | + bidi_cache[bidi_cache_idx - 1].nchars - 1)) | |
b7b65b15 EZ |
2532 | bidi_cache_reset (); |
2533 | /* But as long as we are caching during forward scan, we must | |
2534 | cache each state, or else the cache integrity will be | |
2535 | compromised: it assumes cached states correspond to buffer | |
2536 | positions 1:1. */ | |
2537 | else | |
2538 | bidi_cache_iterator_state (bidi_it, 1); | |
2539 | } | |
acb28818 EZ |
2540 | |
2541 | if (STRINGP (bidi_it->string.lstring)) | |
2542 | UNGCPRO; | |
b7b65b15 EZ |
2543 | } |
2544 | ||
2545 | /* This is meant to be called from within the debugger, whenever you | |
2546 | wish to examine the cache contents. */ | |
e78aecca | 2547 | void bidi_dump_cached_states (void) EXTERNALLY_VISIBLE; |
b7b65b15 EZ |
2548 | void |
2549 | bidi_dump_cached_states (void) | |
2550 | { | |
39e378da | 2551 | ptrdiff_t i; |
b7b65b15 EZ |
2552 | int ndigits = 1; |
2553 | ||
2554 | if (bidi_cache_idx == 0) | |
2555 | { | |
2556 | fprintf (stderr, "The cache is empty.\n"); | |
2557 | return; | |
2558 | } | |
df9733bf | 2559 | fprintf (stderr, "Total of %"pD"d state%s in cache:\n", |
b7b65b15 EZ |
2560 | bidi_cache_idx, bidi_cache_idx == 1 ? "" : "s"); |
2561 | ||
2562 | for (i = bidi_cache[bidi_cache_idx - 1].charpos; i > 0; i /= 10) | |
2563 | ndigits++; | |
2564 | fputs ("ch ", stderr); | |
2565 | for (i = 0; i < bidi_cache_idx; i++) | |
2566 | fprintf (stderr, "%*c", ndigits, bidi_cache[i].ch); | |
2567 | fputs ("\n", stderr); | |
2568 | fputs ("lvl ", stderr); | |
2569 | for (i = 0; i < bidi_cache_idx; i++) | |
2570 | fprintf (stderr, "%*d", ndigits, bidi_cache[i].resolved_level); | |
2571 | fputs ("\n", stderr); | |
2572 | fputs ("pos ", stderr); | |
2573 | for (i = 0; i < bidi_cache_idx; i++) | |
7c85f529 | 2574 | fprintf (stderr, "%*"pD"d", ndigits, bidi_cache[i].charpos); |
b7b65b15 EZ |
2575 | fputs ("\n", stderr); |
2576 | } |