1 /* Low-level bidirectional buffer/string-scanning functions for GNU Emacs.
2 Copyright (C) 2000-2001, 2004-2005, 2009-2011
3 Free Software Foundation, Inc.
5 This file is part of GNU Emacs.
7 GNU Emacs is free software: you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation, either version 3 of the License, or
10 (at your option) any later version.
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.
17 You should have received a copy of the GNU General Public License
18 along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. */
20 /* Written by Eli Zaretskii <eliz@gnu.org>.
22 A sequential implementation of the Unicode Bidirectional algorithm,
23 (UBA) as per UAX#9, a part of the Unicode Standard.
25 Unlike the reference and most other implementations, this one is
26 designed to be called once for every character in the buffer or
29 The main entry point is bidi_move_to_visually_next. Each time it
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
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
36 character by resolving their levels on the fly.
38 Two other entry points are bidi_paragraph_init and
39 bidi_mirror_char. The first determines the base direction of a
40 paragraph, while the second returns the mirrored version of its
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
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.
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
54 rule X9 and to its modifications decribed in the "Implementation
55 Notes" section of UAX#9, under "Retaining Format Codes". */
63 #include "character.h"
64 #include "dispextern.h"
66 static int bidi_initialized
= 0;
68 static Lisp_Object bidi_type_table
, bidi_mirror_table
;
70 #define LRM_CHAR 0x200E
71 #define RLM_CHAR 0x200F
74 /* Data type for describing the bidirectional character categories. */
82 /* UAX#9 says to search only for L, AL, or R types of characters, and
83 ignore RLE, RLO, LRE, and LRO, when determining the base paragraph
84 level. Yudit indeed ignores them. This variable is therefore set
85 by default to ignore them, but setting it to zero will take them
87 extern int bidi_ignore_explicit_marks_for_paragraph_level EXTERNALLY_VISIBLE
;
88 int bidi_ignore_explicit_marks_for_paragraph_level
= 1;
90 static Lisp_Object paragraph_start_re
, paragraph_separate_re
;
91 static Lisp_Object Qparagraph_start
, Qparagraph_separate
;
94 /***********************************************************************
96 ***********************************************************************/
98 /* Return the bidi type of a character CH, subject to the current
99 directional OVERRIDE. */
100 static inline bidi_type_t
101 bidi_get_type (int ch
, bidi_dir_t override
)
103 bidi_type_t default_type
;
107 if (ch
< 0 || ch
> MAX_CHAR
)
110 default_type
= (bidi_type_t
) XINT (CHAR_TABLE_REF (bidi_type_table
, ch
));
111 /* Every valid character code, even those that are unassigned by the
112 UCD, have some bidi-class property, according to
113 DerivedBidiClass.txt file. Therefore, if we ever get UNKNOWN_BT
114 (= zero) code from CHAR_TABLE_REF, that's a bug. */
115 if (default_type
== UNKNOWN_BT
)
118 if (override
== NEUTRAL_DIR
)
121 switch (default_type
)
123 /* Although UAX#9 does not tell, it doesn't make sense to
124 override NEUTRAL_B and LRM/RLM characters. */
139 if (override
== L2R
) /* X6 */
141 else if (override
== R2L
)
144 abort (); /* can't happen: handled above */
150 bidi_check_type (bidi_type_t type
)
152 xassert (UNKNOWN_BT
<= type
&& type
<= NEUTRAL_ON
);
155 /* Given a bidi TYPE of a character, return its category. */
156 static inline bidi_category_t
157 bidi_get_category (bidi_type_t type
)
171 case PDF
: /* ??? really?? */
190 /* Return the mirrored character of C, if it has one. If C has no
191 mirrored counterpart, return C.
192 Note: The conditions in UAX#9 clause L4 regarding the surrounding
193 context must be tested by the caller. */
195 bidi_mirror_char (int c
)
201 if (c
< 0 || c
> MAX_CHAR
)
204 val
= CHAR_TABLE_REF (bidi_mirror_table
, c
);
209 if (v
< 0 || v
> MAX_CHAR
)
218 /* Determine the start-of-run (sor) directional type given the two
219 embedding levels on either side of the run boundary. Also, update
220 the saved info about previously seen characters, since that info is
221 generally valid for a single level run. */
223 bidi_set_sor_type (struct bidi_it
*bidi_it
, int level_before
, int level_after
)
225 int higher_level
= level_before
> level_after
? level_before
: level_after
;
227 /* The prev_was_pdf gork is required for when we have several PDFs
228 in a row. In that case, we want to compute the sor type for the
229 next level run only once: when we see the first PDF. That's
230 because the sor type depends only on the higher of the two levels
231 that we find on the two sides of the level boundary (see UAX#9,
232 clause X10), and so we don't need to know the final embedding
233 level to which we descend after processing all the PDFs. */
234 if (!bidi_it
->prev_was_pdf
|| level_before
< level_after
)
235 /* FIXME: should the default sor direction be user selectable? */
236 bidi_it
->sor
= (higher_level
& 1) != 0 ? R2L
: L2R
;
237 if (level_before
> level_after
)
238 bidi_it
->prev_was_pdf
= 1;
240 bidi_it
->prev
.type
= UNKNOWN_BT
;
241 bidi_it
->last_strong
.type
= bidi_it
->last_strong
.type_after_w1
=
242 bidi_it
->last_strong
.orig_type
= UNKNOWN_BT
;
243 bidi_it
->prev_for_neutral
.type
= bidi_it
->sor
== R2L
? STRONG_R
: STRONG_L
;
244 bidi_it
->prev_for_neutral
.charpos
= bidi_it
->charpos
;
245 bidi_it
->prev_for_neutral
.bytepos
= bidi_it
->bytepos
;
246 bidi_it
->next_for_neutral
.type
= bidi_it
->next_for_neutral
.type_after_w1
=
247 bidi_it
->next_for_neutral
.orig_type
= UNKNOWN_BT
;
248 bidi_it
->ignore_bn_limit
= -1; /* meaning it's unknown */
251 /* Push the current embedding level and override status; reset the
252 current level to LEVEL and the current override status to OVERRIDE. */
254 bidi_push_embedding_level (struct bidi_it
*bidi_it
,
255 int level
, bidi_dir_t override
)
257 bidi_it
->stack_idx
++;
258 xassert (bidi_it
->stack_idx
< BIDI_MAXLEVEL
);
259 bidi_it
->level_stack
[bidi_it
->stack_idx
].level
= level
;
260 bidi_it
->level_stack
[bidi_it
->stack_idx
].override
= override
;
263 /* Pop the embedding level and directional override status from the
264 stack, and return the new level. */
266 bidi_pop_embedding_level (struct bidi_it
*bidi_it
)
268 /* UAX#9 says to ignore invalid PDFs. */
269 if (bidi_it
->stack_idx
> 0)
270 bidi_it
->stack_idx
--;
271 return bidi_it
->level_stack
[bidi_it
->stack_idx
].level
;
274 /* Record in SAVED_INFO the information about the current character. */
276 bidi_remember_char (struct bidi_saved_info
*saved_info
,
277 struct bidi_it
*bidi_it
)
279 saved_info
->charpos
= bidi_it
->charpos
;
280 saved_info
->bytepos
= bidi_it
->bytepos
;
281 saved_info
->type
= bidi_it
->type
;
282 bidi_check_type (bidi_it
->type
);
283 saved_info
->type_after_w1
= bidi_it
->type_after_w1
;
284 bidi_check_type (bidi_it
->type_after_w1
);
285 saved_info
->orig_type
= bidi_it
->orig_type
;
286 bidi_check_type (bidi_it
->orig_type
);
289 /* Copy the bidi iterator from FROM to TO. To save cycles, this only
290 copies the part of the level stack that is actually in use. */
292 bidi_copy_it (struct bidi_it
*to
, struct bidi_it
*from
)
296 /* Copy everything except the level stack and beyond. */
297 memcpy (to
, from
, offsetof (struct bidi_it
, level_stack
[0]));
299 /* Copy the active part of the level stack. */
300 to
->level_stack
[0] = from
->level_stack
[0]; /* level zero is always in use */
301 for (i
= 1; i
<= from
->stack_idx
; i
++)
302 to
->level_stack
[i
] = from
->level_stack
[i
];
306 /***********************************************************************
307 Caching the bidi iterator states
308 ***********************************************************************/
310 #define BIDI_CACHE_CHUNK 200
311 static struct bidi_it
*bidi_cache
;
312 static ptrdiff_t bidi_cache_size
= 0;
313 enum { elsz
= sizeof (struct bidi_it
) };
314 static ptrdiff_t bidi_cache_idx
; /* next unused cache slot */
315 static ptrdiff_t bidi_cache_last_idx
; /* slot of last cache hit */
316 static ptrdiff_t bidi_cache_start
= 0; /* start of cache for this
319 /* 5-slot stack for saving the start of the previous level of the
320 cache. xdisp.c maintains a 5-slot stack for its iterator state,
321 and we need the same size of our stack. */
322 static ptrdiff_t bidi_cache_start_stack
[IT_STACK_SIZE
];
323 static int bidi_cache_sp
;
325 /* Size of header used by bidi_shelve_cache. */
328 bidi_shelve_header_size
=
329 (sizeof (bidi_cache_idx
) + sizeof (bidi_cache_start_stack
)
330 + sizeof (bidi_cache_sp
) + sizeof (bidi_cache_start
)
331 + sizeof (bidi_cache_last_idx
))
334 /* Reset the cache state to the empty state. We only reset the part
335 of the cache relevant to iteration of the current object. Previous
336 objects, which are pushed on the display iterator's stack, are left
337 intact. This is called when the cached information is no more
338 useful for the current iteration, e.g. when we were reseated to a
339 new position on the same object. */
341 bidi_cache_reset (void)
343 bidi_cache_idx
= bidi_cache_start
;
344 bidi_cache_last_idx
= -1;
347 /* Shrink the cache to its minimal size. Called when we init the bidi
348 iterator for reordering a buffer or a string that does not come
349 from display properties, because that means all the previously
350 cached info is of no further use. */
352 bidi_cache_shrink (void)
354 if (bidi_cache_size
> BIDI_CACHE_CHUNK
)
357 (struct bidi_it
*) xrealloc (bidi_cache
, BIDI_CACHE_CHUNK
* elsz
);
358 bidi_cache_size
= BIDI_CACHE_CHUNK
;
364 bidi_cache_fetch_state (ptrdiff_t idx
, struct bidi_it
*bidi_it
)
366 int current_scan_dir
= bidi_it
->scan_dir
;
368 if (idx
< bidi_cache_start
|| idx
>= bidi_cache_idx
)
371 bidi_copy_it (bidi_it
, &bidi_cache
[idx
]);
372 bidi_it
->scan_dir
= current_scan_dir
;
373 bidi_cache_last_idx
= idx
;
376 /* Find a cached state with a given CHARPOS and resolved embedding
377 level less or equal to LEVEL. if LEVEL is -1, disregard the
378 resolved levels in cached states. DIR, if non-zero, means search
379 in that direction from the last cache hit. */
380 static inline ptrdiff_t
381 bidi_cache_search (EMACS_INT charpos
, int level
, int dir
)
383 ptrdiff_t i
, i_start
;
385 if (bidi_cache_idx
> bidi_cache_start
)
387 if (bidi_cache_last_idx
== -1)
388 bidi_cache_last_idx
= bidi_cache_idx
- 1;
389 if (charpos
< bidi_cache
[bidi_cache_last_idx
].charpos
)
392 i_start
= bidi_cache_last_idx
- 1;
394 else if (charpos
> (bidi_cache
[bidi_cache_last_idx
].charpos
395 + bidi_cache
[bidi_cache_last_idx
].nchars
- 1))
398 i_start
= bidi_cache_last_idx
+ 1;
401 i_start
= bidi_cache_last_idx
;
405 i_start
= bidi_cache_idx
- 1;
410 /* Linear search for now; FIXME! */
411 for (i
= i_start
; i
>= bidi_cache_start
; i
--)
412 if (bidi_cache
[i
].charpos
<= charpos
413 && charpos
< bidi_cache
[i
].charpos
+ bidi_cache
[i
].nchars
414 && (level
== -1 || bidi_cache
[i
].resolved_level
<= level
))
419 for (i
= i_start
; i
< bidi_cache_idx
; i
++)
420 if (bidi_cache
[i
].charpos
<= charpos
421 && charpos
< bidi_cache
[i
].charpos
+ bidi_cache
[i
].nchars
422 && (level
== -1 || bidi_cache
[i
].resolved_level
<= level
))
430 /* Find a cached state where the resolved level changes to a value
431 that is lower than LEVEL, and return its cache slot index. DIR is
432 the direction to search, starting with the last used cache slot.
433 If DIR is zero, we search backwards from the last occupied cache
434 slot. BEFORE, if non-zero, means return the index of the slot that
435 is ``before'' the level change in the search direction. That is,
436 given the cached levels like this:
441 and assuming we are at the position cached at the slot marked with
442 C, searching backwards (DIR = -1) for LEVEL = 2 will return the
443 index of slot B or A, depending whether BEFORE is, respectively,
446 bidi_cache_find_level_change (int level
, int dir
, int before
)
450 ptrdiff_t i
= dir
? bidi_cache_last_idx
: bidi_cache_idx
- 1;
451 int incr
= before
? 1 : 0;
453 xassert (!dir
|| bidi_cache_last_idx
>= 0);
462 while (i
>= bidi_cache_start
+ incr
)
464 if (bidi_cache
[i
- incr
].resolved_level
>= 0
465 && bidi_cache
[i
- incr
].resolved_level
< level
)
472 while (i
< bidi_cache_idx
- incr
)
474 if (bidi_cache
[i
+ incr
].resolved_level
>= 0
475 && bidi_cache
[i
+ incr
].resolved_level
< level
)
486 bidi_cache_ensure_space (ptrdiff_t idx
)
488 /* Enlarge the cache as needed. */
489 if (idx
>= bidi_cache_size
)
491 /* The bidi cache cannot be larger than the largest Lisp string
493 ptrdiff_t string_or_buffer_bound
=
494 max (BUF_BYTES_MAX
, STRING_BYTES_BOUND
);
496 /* Also, it cannot be larger than what C can represent. */
498 (min (PTRDIFF_MAX
, SIZE_MAX
) - bidi_shelve_header_size
) / elsz
;
501 xpalloc (bidi_cache
, &bidi_cache_size
,
502 max (BIDI_CACHE_CHUNK
, idx
- bidi_cache_size
+ 1),
503 min (string_or_buffer_bound
, c_bound
), elsz
);
508 bidi_cache_iterator_state (struct bidi_it
*bidi_it
, int resolved
)
512 /* We should never cache on backward scans. */
513 if (bidi_it
->scan_dir
== -1)
515 idx
= bidi_cache_search (bidi_it
->charpos
, -1, 1);
519 idx
= bidi_cache_idx
;
520 bidi_cache_ensure_space (idx
);
521 /* Character positions should correspond to cache positions 1:1.
522 If we are outside the range of cached positions, the cache is
523 useless and must be reset. */
524 if (idx
> bidi_cache_start
&&
525 (bidi_it
->charpos
> (bidi_cache
[idx
- 1].charpos
526 + bidi_cache
[idx
- 1].nchars
)
527 || bidi_it
->charpos
< bidi_cache
[bidi_cache_start
].charpos
))
530 idx
= bidi_cache_start
;
532 if (bidi_it
->nchars
<= 0)
534 bidi_copy_it (&bidi_cache
[idx
], bidi_it
);
536 bidi_cache
[idx
].resolved_level
= -1;
540 /* Copy only the members which could have changed, to avoid
541 costly copying of the entire struct. */
542 bidi_cache
[idx
].type
= bidi_it
->type
;
543 bidi_check_type (bidi_it
->type
);
544 bidi_cache
[idx
].type_after_w1
= bidi_it
->type_after_w1
;
545 bidi_check_type (bidi_it
->type_after_w1
);
547 bidi_cache
[idx
].resolved_level
= bidi_it
->resolved_level
;
549 bidi_cache
[idx
].resolved_level
= -1;
550 bidi_cache
[idx
].invalid_levels
= bidi_it
->invalid_levels
;
551 bidi_cache
[idx
].invalid_rl_levels
= bidi_it
->invalid_rl_levels
;
552 bidi_cache
[idx
].next_for_neutral
= bidi_it
->next_for_neutral
;
553 bidi_cache
[idx
].next_for_ws
= bidi_it
->next_for_ws
;
554 bidi_cache
[idx
].ignore_bn_limit
= bidi_it
->ignore_bn_limit
;
555 bidi_cache
[idx
].disp_pos
= bidi_it
->disp_pos
;
556 bidi_cache
[idx
].disp_prop
= bidi_it
->disp_prop
;
559 bidi_cache_last_idx
= idx
;
560 if (idx
>= bidi_cache_idx
)
561 bidi_cache_idx
= idx
+ 1;
564 static inline bidi_type_t
565 bidi_cache_find (EMACS_INT charpos
, int level
, struct bidi_it
*bidi_it
)
567 ptrdiff_t i
= bidi_cache_search (charpos
, level
, bidi_it
->scan_dir
);
569 if (i
>= bidi_cache_start
)
571 bidi_dir_t current_scan_dir
= bidi_it
->scan_dir
;
573 bidi_copy_it (bidi_it
, &bidi_cache
[i
]);
574 bidi_cache_last_idx
= i
;
575 /* Don't let scan direction from from the cached state override
576 the current scan direction. */
577 bidi_it
->scan_dir
= current_scan_dir
;
578 return bidi_it
->type
;
585 bidi_peek_at_next_level (struct bidi_it
*bidi_it
)
587 if (bidi_cache_idx
== bidi_cache_start
|| bidi_cache_last_idx
== -1)
589 return bidi_cache
[bidi_cache_last_idx
+ bidi_it
->scan_dir
].resolved_level
;
593 /***********************************************************************
594 Pushing and popping the bidi iterator state
595 ***********************************************************************/
597 /* Push the bidi iterator state in preparation for reordering a
598 different object, e.g. display string found at certain buffer
599 position. Pushing the bidi iterator boils down to saving its
600 entire state on the cache and starting a new cache "stacked" on top
601 of the current cache. */
603 bidi_push_it (struct bidi_it
*bidi_it
)
605 /* Save the current iterator state in its entirety after the last
607 bidi_cache_ensure_space (bidi_cache_idx
);
608 memcpy (&bidi_cache
[bidi_cache_idx
++], bidi_it
, sizeof (struct bidi_it
));
610 /* Push the current cache start onto the stack. */
611 xassert (bidi_cache_sp
< IT_STACK_SIZE
);
612 bidi_cache_start_stack
[bidi_cache_sp
++] = bidi_cache_start
;
614 /* Start a new level of cache, and make it empty. */
615 bidi_cache_start
= bidi_cache_idx
;
616 bidi_cache_last_idx
= -1;
619 /* Restore the iterator state saved by bidi_push_it and return the
620 cache to the corresponding state. */
622 bidi_pop_it (struct bidi_it
*bidi_it
)
624 if (bidi_cache_start
<= 0)
627 /* Reset the next free cache slot index to what it was before the
628 call to bidi_push_it. */
629 bidi_cache_idx
= bidi_cache_start
- 1;
631 /* Restore the bidi iterator state saved in the cache. */
632 memcpy (bidi_it
, &bidi_cache
[bidi_cache_idx
], sizeof (struct bidi_it
));
634 /* Pop the previous cache start from the stack. */
635 if (bidi_cache_sp
<= 0)
637 bidi_cache_start
= bidi_cache_start_stack
[--bidi_cache_sp
];
639 /* Invalidate the last-used cache slot data. */
640 bidi_cache_last_idx
= -1;
643 static ptrdiff_t bidi_cache_total_alloc
;
645 /* Stash away a copy of the cache and its control variables. */
647 bidi_shelve_cache (void)
649 unsigned char *databuf
;
653 if (bidi_cache_idx
== 0)
656 alloc
= (bidi_shelve_header_size
657 + bidi_cache_idx
* sizeof (struct bidi_it
));
658 databuf
= xmalloc (alloc
);
659 bidi_cache_total_alloc
+= alloc
;
661 memcpy (databuf
, &bidi_cache_idx
, sizeof (bidi_cache_idx
));
662 memcpy (databuf
+ sizeof (bidi_cache_idx
),
663 bidi_cache
, bidi_cache_idx
* sizeof (struct bidi_it
));
664 memcpy (databuf
+ sizeof (bidi_cache_idx
)
665 + bidi_cache_idx
* sizeof (struct bidi_it
),
666 bidi_cache_start_stack
, sizeof (bidi_cache_start_stack
));
667 memcpy (databuf
+ sizeof (bidi_cache_idx
)
668 + bidi_cache_idx
* sizeof (struct bidi_it
)
669 + sizeof (bidi_cache_start_stack
),
670 &bidi_cache_sp
, sizeof (bidi_cache_sp
));
671 memcpy (databuf
+ sizeof (bidi_cache_idx
)
672 + bidi_cache_idx
* sizeof (struct bidi_it
)
673 + sizeof (bidi_cache_start_stack
) + sizeof (bidi_cache_sp
),
674 &bidi_cache_start
, sizeof (bidi_cache_start
));
675 memcpy (databuf
+ sizeof (bidi_cache_idx
)
676 + bidi_cache_idx
* sizeof (struct bidi_it
)
677 + sizeof (bidi_cache_start_stack
) + sizeof (bidi_cache_sp
)
678 + sizeof (bidi_cache_start
),
679 &bidi_cache_last_idx
, sizeof (bidi_cache_last_idx
));
684 /* Restore the cache state from a copy stashed away by
685 bidi_shelve_cache, and free the buffer used to stash that copy.
686 JUST_FREE non-zero means free the buffer, but don't restore the
687 cache; used when the corresponding iterator is discarded instead of
690 bidi_unshelve_cache (void *databuf
, int just_free
)
692 unsigned char *p
= databuf
;
698 /* A NULL pointer means an empty cache. */
699 bidi_cache_start
= 0;
710 memcpy (&idx
, p
, sizeof (bidi_cache_idx
));
711 bidi_cache_total_alloc
-=
712 bidi_shelve_header_size
+ idx
* sizeof (struct bidi_it
);
716 memcpy (&bidi_cache_idx
, p
, sizeof (bidi_cache_idx
));
717 bidi_cache_ensure_space (bidi_cache_idx
);
718 memcpy (bidi_cache
, p
+ sizeof (bidi_cache_idx
),
719 bidi_cache_idx
* sizeof (struct bidi_it
));
720 memcpy (bidi_cache_start_stack
,
721 p
+ sizeof (bidi_cache_idx
)
722 + bidi_cache_idx
* sizeof (struct bidi_it
),
723 sizeof (bidi_cache_start_stack
));
724 memcpy (&bidi_cache_sp
,
725 p
+ sizeof (bidi_cache_idx
)
726 + bidi_cache_idx
* sizeof (struct bidi_it
)
727 + sizeof (bidi_cache_start_stack
),
728 sizeof (bidi_cache_sp
));
729 memcpy (&bidi_cache_start
,
730 p
+ sizeof (bidi_cache_idx
)
731 + bidi_cache_idx
* sizeof (struct bidi_it
)
732 + sizeof (bidi_cache_start_stack
) + sizeof (bidi_cache_sp
),
733 sizeof (bidi_cache_start
));
734 memcpy (&bidi_cache_last_idx
,
735 p
+ sizeof (bidi_cache_idx
)
736 + bidi_cache_idx
* sizeof (struct bidi_it
)
737 + sizeof (bidi_cache_start_stack
) + sizeof (bidi_cache_sp
)
738 + sizeof (bidi_cache_start
),
739 sizeof (bidi_cache_last_idx
));
740 bidi_cache_total_alloc
-=
741 bidi_shelve_header_size
+ bidi_cache_idx
* sizeof (struct bidi_it
);
749 /***********************************************************************
751 ***********************************************************************/
753 bidi_initialize (void)
755 bidi_type_table
= uniprop_table (intern ("bidi-class"));
756 if (NILP (bidi_type_table
))
758 staticpro (&bidi_type_table
);
760 bidi_mirror_table
= uniprop_table (intern ("mirroring"));
761 if (NILP (bidi_mirror_table
))
763 staticpro (&bidi_mirror_table
);
765 Qparagraph_start
= intern ("paragraph-start");
766 staticpro (&Qparagraph_start
);
767 paragraph_start_re
= Fsymbol_value (Qparagraph_start
);
768 if (!STRINGP (paragraph_start_re
))
769 paragraph_start_re
= build_string ("\f\\|[ \t]*$");
770 staticpro (¶graph_start_re
);
771 Qparagraph_separate
= intern ("paragraph-separate");
772 staticpro (&Qparagraph_separate
);
773 paragraph_separate_re
= Fsymbol_value (Qparagraph_separate
);
774 if (!STRINGP (paragraph_separate_re
))
775 paragraph_separate_re
= build_string ("[ \t\f]*$");
776 staticpro (¶graph_separate_re
);
779 bidi_cache_total_alloc
= 0;
781 bidi_initialized
= 1;
784 /* Do whatever UAX#9 clause X8 says should be done at paragraph's
787 bidi_set_paragraph_end (struct bidi_it
*bidi_it
)
789 bidi_it
->invalid_levels
= 0;
790 bidi_it
->invalid_rl_levels
= -1;
791 bidi_it
->stack_idx
= 0;
792 bidi_it
->resolved_level
= bidi_it
->level_stack
[0].level
;
795 /* Initialize the bidi iterator from buffer/string position CHARPOS. */
797 bidi_init_it (EMACS_INT charpos
, EMACS_INT bytepos
, int frame_window_p
,
798 struct bidi_it
*bidi_it
)
800 if (! bidi_initialized
)
803 bidi_it
->charpos
= charpos
;
805 bidi_it
->bytepos
= bytepos
;
806 bidi_it
->frame_window_p
= frame_window_p
;
807 bidi_it
->nchars
= -1; /* to be computed in bidi_resolve_explicit_1 */
808 bidi_it
->first_elt
= 1;
809 bidi_set_paragraph_end (bidi_it
);
810 bidi_it
->new_paragraph
= 1;
811 bidi_it
->separator_limit
= -1;
812 bidi_it
->type
= NEUTRAL_B
;
813 bidi_it
->type_after_w1
= NEUTRAL_B
;
814 bidi_it
->orig_type
= NEUTRAL_B
;
815 bidi_it
->prev_was_pdf
= 0;
816 bidi_it
->prev
.type
= bidi_it
->prev
.type_after_w1
=
817 bidi_it
->prev
.orig_type
= UNKNOWN_BT
;
818 bidi_it
->last_strong
.type
= bidi_it
->last_strong
.type_after_w1
=
819 bidi_it
->last_strong
.orig_type
= UNKNOWN_BT
;
820 bidi_it
->next_for_neutral
.charpos
= -1;
821 bidi_it
->next_for_neutral
.type
=
822 bidi_it
->next_for_neutral
.type_after_w1
=
823 bidi_it
->next_for_neutral
.orig_type
= UNKNOWN_BT
;
824 bidi_it
->prev_for_neutral
.charpos
= -1;
825 bidi_it
->prev_for_neutral
.type
=
826 bidi_it
->prev_for_neutral
.type_after_w1
=
827 bidi_it
->prev_for_neutral
.orig_type
= UNKNOWN_BT
;
828 bidi_it
->sor
= L2R
; /* FIXME: should it be user-selectable? */
829 bidi_it
->disp_pos
= -1; /* invalid/unknown */
830 bidi_it
->disp_prop
= 0;
831 /* We can only shrink the cache if we are at the bottom level of its
833 if (bidi_cache_start
== 0)
834 bidi_cache_shrink ();
839 /* Perform initializations for reordering a new line of bidi text. */
841 bidi_line_init (struct bidi_it
*bidi_it
)
843 bidi_it
->scan_dir
= 1; /* FIXME: do we need to have control on this? */
844 bidi_it
->resolved_level
= bidi_it
->level_stack
[0].level
;
845 bidi_it
->level_stack
[0].override
= NEUTRAL_DIR
; /* X1 */
846 bidi_it
->invalid_levels
= 0;
847 bidi_it
->invalid_rl_levels
= -1;
848 bidi_it
->next_en_pos
= -1;
849 bidi_it
->next_for_ws
.type
= UNKNOWN_BT
;
850 bidi_set_sor_type (bidi_it
,
851 bidi_it
->paragraph_dir
== R2L
? 1 : 0,
852 bidi_it
->level_stack
[0].level
); /* X10 */
858 /***********************************************************************
860 ***********************************************************************/
862 /* Count bytes in string S between BEG/BEGBYTE and END. BEG and END
863 are zero-based character positions in S, BEGBYTE is byte position
864 corresponding to BEG. UNIBYTE, if non-zero, means S is a unibyte
866 static inline EMACS_INT
867 bidi_count_bytes (const unsigned char *s
, const EMACS_INT beg
,
868 const EMACS_INT begbyte
, const EMACS_INT end
, int unibyte
)
871 const unsigned char *p
= s
+ begbyte
, *start
= p
;
877 if (!CHAR_HEAD_P (*p
))
882 p
+= BYTES_BY_CHAR_HEAD (*p
);
890 /* Fetch and returns the character at byte position BYTEPOS. If S is
891 non-NULL, fetch the character from string S; otherwise fetch the
892 character from the current buffer. UNIBYTE non-zero means S is a
895 bidi_char_at_pos (EMACS_INT bytepos
, const unsigned char *s
, int unibyte
)
902 return STRING_CHAR (s
+ bytepos
);
905 return FETCH_MULTIBYTE_CHAR (bytepos
);
908 /* Fetch and return the character at BYTEPOS/CHARPOS. If that
909 character is covered by a display string, treat the entire run of
910 covered characters as a single character, either u+2029 or u+FFFC,
911 and return their combined length in CH_LEN and NCHARS. DISP_POS
912 specifies the character position of the next display string, or -1
913 if not yet computed. When the next character is at or beyond that
914 position, the function updates DISP_POS with the position of the
915 next display string. DISP_PROP non-zero means that there's really
916 a display string at DISP_POS, as opposed to when we searched till
917 DISP_POS without finding one. If DISP_PROP is 2, it means the
918 display spec is of the form `(space ...)', which is replaced with
919 u+2029 to handle it as a paragraph separator. STRING->s is the C
920 string to iterate, or NULL if iterating over a buffer or a Lisp
921 string; in the latter case, STRING->lstring is the Lisp string. */
923 bidi_fetch_char (EMACS_INT bytepos
, EMACS_INT charpos
, EMACS_INT
*disp_pos
,
924 int *disp_prop
, struct bidi_string_data
*string
,
925 int frame_window_p
, EMACS_INT
*ch_len
, EMACS_INT
*nchars
)
929 (string
->s
|| STRINGP (string
->lstring
)) ? string
->schars
: ZV
;
932 /* If we got past the last known position of display string, compute
933 the position of the next one. That position could be at CHARPOS. */
934 if (charpos
< endpos
&& charpos
> *disp_pos
)
936 SET_TEXT_POS (pos
, charpos
, bytepos
);
937 *disp_pos
= compute_display_string_pos (&pos
, string
, frame_window_p
,
941 /* Fetch the character at BYTEPOS. */
942 if (charpos
>= endpos
)
950 else if (charpos
>= *disp_pos
&& *disp_prop
)
952 EMACS_INT disp_end_pos
;
954 /* We don't expect to find ourselves in the middle of a display
955 property. Hopefully, it will never be needed. */
956 if (charpos
> *disp_pos
)
958 /* Text covered by `display' properties and overlays with
959 display properties or display strings is handled as a single
960 character that represents the entire run of characters
961 covered by the display property. */
964 /* `(space ...)' display specs are handled as paragraph
965 separators for the purposes of the reordering; see UAX#9
966 section 3 and clause HL1 in section 4.3 there. */
971 /* All other display specs are handled as the Unicode Object
972 Replacement Character. */
975 disp_end_pos
= compute_display_string_end (*disp_pos
, string
);
976 *nchars
= disp_end_pos
- *disp_pos
;
980 *ch_len
= bidi_count_bytes (string
->s
, *disp_pos
, bytepos
,
981 disp_end_pos
, string
->unibyte
);
982 else if (STRINGP (string
->lstring
))
983 *ch_len
= bidi_count_bytes (SDATA (string
->lstring
), *disp_pos
,
984 bytepos
, disp_end_pos
, string
->unibyte
);
986 *ch_len
= CHAR_TO_BYTE (disp_end_pos
) - bytepos
;
994 if (!string
->unibyte
)
996 ch
= STRING_CHAR_AND_LENGTH (string
->s
+ bytepos
, len
);
1001 ch
= UNIBYTE_TO_CHAR (string
->s
[bytepos
]);
1005 else if (STRINGP (string
->lstring
))
1009 if (!string
->unibyte
)
1011 ch
= STRING_CHAR_AND_LENGTH (SDATA (string
->lstring
) + bytepos
,
1017 ch
= UNIBYTE_TO_CHAR (SREF (string
->lstring
, bytepos
));
1023 ch
= FETCH_MULTIBYTE_CHAR (bytepos
);
1024 *ch_len
= CHAR_BYTES (ch
);
1029 /* If we just entered a run of characters covered by a display
1030 string, compute the position of the next display string. */
1031 if (charpos
+ *nchars
<= endpos
&& charpos
+ *nchars
> *disp_pos
1034 SET_TEXT_POS (pos
, charpos
+ *nchars
, bytepos
+ *ch_len
);
1035 *disp_pos
= compute_display_string_pos (&pos
, string
, frame_window_p
,
1043 /***********************************************************************
1044 Determining paragraph direction
1045 ***********************************************************************/
1047 /* Check if buffer position CHARPOS/BYTEPOS is the end of a paragraph.
1048 Value is the non-negative length of the paragraph separator
1049 following the buffer position, -1 if position is at the beginning
1050 of a new paragraph, or -2 if position is neither at beginning nor
1051 at end of a paragraph. */
1053 bidi_at_paragraph_end (EMACS_INT charpos
, EMACS_INT bytepos
)
1056 Lisp_Object start_re
;
1059 sep_re
= paragraph_separate_re
;
1060 start_re
= paragraph_start_re
;
1062 val
= fast_looking_at (sep_re
, charpos
, bytepos
, ZV
, ZV_BYTE
, Qnil
);
1065 if (fast_looking_at (start_re
, charpos
, bytepos
, ZV
, ZV_BYTE
, Qnil
) >= 0)
1074 /* On my 2005-vintage machine, searching back for paragraph start
1075 takes ~1 ms per line. And bidi_paragraph_init is called 4 times
1076 when user types C-p. The number below limits each call to
1077 bidi_paragraph_init to about 10 ms. */
1078 #define MAX_PARAGRAPH_SEARCH 7500
1080 /* Find the beginning of this paragraph by looking back in the buffer.
1081 Value is the byte position of the paragraph's beginning, or
1082 BEGV_BYTE if paragraph_start_re is still not found after looking
1083 back MAX_PARAGRAPH_SEARCH lines in the buffer. */
1085 bidi_find_paragraph_start (EMACS_INT pos
, EMACS_INT pos_byte
)
1087 Lisp_Object re
= paragraph_start_re
;
1088 EMACS_INT limit
= ZV
, limit_byte
= ZV_BYTE
;
1091 while (pos_byte
> BEGV_BYTE
1092 && n
++ < MAX_PARAGRAPH_SEARCH
1093 && fast_looking_at (re
, pos
, pos_byte
, limit
, limit_byte
, Qnil
) < 0)
1095 /* FIXME: What if the paragraph beginning is covered by a
1096 display string? And what if a display string covering some
1097 of the text over which we scan back includes
1098 paragraph_start_re? */
1099 pos
= find_next_newline_no_quit (pos
- 1, -1);
1100 pos_byte
= CHAR_TO_BYTE (pos
);
1102 if (n
>= MAX_PARAGRAPH_SEARCH
)
1103 pos_byte
= BEGV_BYTE
;
1107 /* Determine the base direction, a.k.a. base embedding level, of the
1108 paragraph we are about to iterate through. If DIR is either L2R or
1109 R2L, just use that. Otherwise, determine the paragraph direction
1110 from the first strong directional character of the paragraph.
1112 NO_DEFAULT_P non-zero means don't default to L2R if the paragraph
1113 has no strong directional characters and both DIR and
1114 bidi_it->paragraph_dir are NEUTRAL_DIR. In that case, search back
1115 in the buffer until a paragraph is found with a strong character,
1116 or until hitting BEGV. In the latter case, fall back to L2R. This
1117 flag is used in current-bidi-paragraph-direction.
1119 Note that this function gives the paragraph separator the same
1120 direction as the preceding paragraph, even though Emacs generally
1121 views the separartor as not belonging to any paragraph. */
1123 bidi_paragraph_init (bidi_dir_t dir
, struct bidi_it
*bidi_it
, int no_default_p
)
1125 EMACS_INT bytepos
= bidi_it
->bytepos
;
1126 int string_p
= bidi_it
->string
.s
!= NULL
|| STRINGP (bidi_it
->string
.lstring
);
1127 EMACS_INT pstartbyte
;
1128 /* Note that begbyte is a byte position, while end is a character
1129 position. Yes, this is ugly, but we are trying to avoid costly
1130 calls to BYTE_TO_CHAR and its ilk. */
1131 EMACS_INT begbyte
= string_p
? 0 : BEGV_BYTE
;
1132 EMACS_INT end
= string_p
? bidi_it
->string
.schars
: ZV
;
1134 /* Special case for an empty buffer. */
1135 if (bytepos
== begbyte
&& bidi_it
->charpos
== end
)
1137 /* We should never be called at EOB or before BEGV. */
1138 else if (bidi_it
->charpos
>= end
|| bytepos
< begbyte
)
1143 bidi_it
->paragraph_dir
= L2R
;
1144 bidi_it
->new_paragraph
= 0;
1146 else if (dir
== R2L
)
1148 bidi_it
->paragraph_dir
= R2L
;
1149 bidi_it
->new_paragraph
= 0;
1151 else if (dir
== NEUTRAL_DIR
) /* P2 */
1154 EMACS_INT ch_len
, nchars
;
1155 EMACS_INT pos
, disp_pos
= -1;
1158 const unsigned char *s
;
1160 if (!bidi_initialized
)
1163 /* If we are inside a paragraph separator, we are just waiting
1164 for the separator to be exhausted; use the previous paragraph
1165 direction. But don't do that if we have been just reseated,
1166 because we need to reinitialize below in that case. */
1167 if (!bidi_it
->first_elt
1168 && bidi_it
->charpos
< bidi_it
->separator_limit
)
1171 /* If we are on a newline, get past it to where the next
1172 paragraph might start. But don't do that at BEGV since then
1173 we are potentially in a new paragraph that doesn't yet
1175 pos
= bidi_it
->charpos
;
1176 s
= STRINGP (bidi_it
->string
.lstring
) ?
1177 SDATA (bidi_it
->string
.lstring
) : bidi_it
->string
.s
;
1178 if (bytepos
> begbyte
1179 && bidi_char_at_pos (bytepos
, s
, bidi_it
->string
.unibyte
) == '\n')
1185 /* We are either at the beginning of a paragraph or in the
1186 middle of it. Find where this paragraph starts. */
1189 /* We don't support changes of paragraph direction inside a
1190 string. It is treated as a single paragraph. */
1194 pstartbyte
= bidi_find_paragraph_start (pos
, bytepos
);
1195 bidi_it
->separator_limit
= -1;
1196 bidi_it
->new_paragraph
= 0;
1198 /* The following loop is run more than once only if NO_DEFAULT_P
1199 is non-zero, and only if we are iterating on a buffer. */
1201 bytepos
= pstartbyte
;
1203 pos
= BYTE_TO_CHAR (bytepos
);
1204 ch
= bidi_fetch_char (bytepos
, pos
, &disp_pos
, &disp_prop
,
1206 bidi_it
->frame_window_p
, &ch_len
, &nchars
);
1207 type
= bidi_get_type (ch
, NEUTRAL_DIR
);
1209 for (pos
+= nchars
, bytepos
+= ch_len
;
1210 (bidi_get_category (type
) != STRONG
)
1211 || (bidi_ignore_explicit_marks_for_paragraph_level
1212 && (type
== RLE
|| type
== RLO
1213 || type
== LRE
|| type
== LRO
));
1214 type
= bidi_get_type (ch
, NEUTRAL_DIR
))
1218 /* Pretend there's a paragraph separator at end of
1224 && type
== NEUTRAL_B
1225 && bidi_at_paragraph_end (pos
, bytepos
) >= -1)
1227 /* Fetch next character and advance to get past it. */
1228 ch
= bidi_fetch_char (bytepos
, pos
, &disp_pos
,
1229 &disp_prop
, &bidi_it
->string
,
1230 bidi_it
->frame_window_p
, &ch_len
, &nchars
);
1234 if ((type
== STRONG_R
|| type
== STRONG_AL
) /* P3 */
1235 || (!bidi_ignore_explicit_marks_for_paragraph_level
1236 && (type
== RLO
|| type
== RLE
)))
1237 bidi_it
->paragraph_dir
= R2L
;
1238 else if (type
== STRONG_L
1239 || (!bidi_ignore_explicit_marks_for_paragraph_level
1240 && (type
== LRO
|| type
== LRE
)))
1241 bidi_it
->paragraph_dir
= L2R
;
1243 && no_default_p
&& bidi_it
->paragraph_dir
== NEUTRAL_DIR
)
1245 /* If this paragraph is at BEGV, default to L2R. */
1246 if (pstartbyte
== BEGV_BYTE
)
1247 bidi_it
->paragraph_dir
= L2R
; /* P3 and HL1 */
1250 EMACS_INT prevpbyte
= pstartbyte
;
1251 EMACS_INT p
= BYTE_TO_CHAR (pstartbyte
), pbyte
= pstartbyte
;
1253 /* Find the beginning of the previous paragraph, if any. */
1254 while (pbyte
> BEGV_BYTE
&& prevpbyte
>= pstartbyte
)
1256 /* FXIME: What if p is covered by a display
1257 string? See also a FIXME inside
1258 bidi_find_paragraph_start. */
1260 pbyte
= CHAR_TO_BYTE (p
);
1261 prevpbyte
= bidi_find_paragraph_start (p
, pbyte
);
1263 pstartbyte
= prevpbyte
;
1267 && no_default_p
&& bidi_it
->paragraph_dir
== NEUTRAL_DIR
);
1272 /* Contrary to UAX#9 clause P3, we only default the paragraph
1273 direction to L2R if we have no previous usable paragraph
1274 direction. This is allowed by the HL1 clause. */
1275 if (bidi_it
->paragraph_dir
!= L2R
&& bidi_it
->paragraph_dir
!= R2L
)
1276 bidi_it
->paragraph_dir
= L2R
; /* P3 and HL1 ``higher-level protocols'' */
1277 if (bidi_it
->paragraph_dir
== R2L
)
1278 bidi_it
->level_stack
[0].level
= 1;
1280 bidi_it
->level_stack
[0].level
= 0;
1282 bidi_line_init (bidi_it
);
1286 /***********************************************************************
1287 Resolving explicit and implicit levels.
1288 The rest of this file constitutes the core of the UBA implementation.
1289 ***********************************************************************/
1292 bidi_explicit_dir_char (int ch
)
1294 bidi_type_t ch_type
;
1296 if (!bidi_initialized
)
1298 ch_type
= (bidi_type_t
) XINT (CHAR_TABLE_REF (bidi_type_table
, ch
));
1299 return (ch_type
== LRE
|| ch_type
== LRO
1300 || ch_type
== RLE
|| ch_type
== RLO
1304 /* A helper function for bidi_resolve_explicit. It advances to the
1305 next character in logical order and determines the new embedding
1306 level and directional override, but does not take into account
1307 empty embeddings. */
1309 bidi_resolve_explicit_1 (struct bidi_it
*bidi_it
)
1315 bidi_dir_t override
;
1316 int string_p
= bidi_it
->string
.s
!= NULL
|| STRINGP (bidi_it
->string
.lstring
);
1318 /* If reseat()'ed, don't advance, so as to start iteration from the
1319 position where we were reseated. bidi_it->bytepos can be less
1320 than BEGV_BYTE after reseat to BEGV. */
1321 if (bidi_it
->bytepos
< (string_p
? 0 : BEGV_BYTE
)
1322 || bidi_it
->first_elt
)
1324 bidi_it
->first_elt
= 0;
1327 const unsigned char *p
=
1328 STRINGP (bidi_it
->string
.lstring
)
1329 ? SDATA (bidi_it
->string
.lstring
) : bidi_it
->string
.s
;
1331 if (bidi_it
->charpos
< 0)
1332 bidi_it
->charpos
= 0;
1333 bidi_it
->bytepos
= bidi_count_bytes (p
, 0, 0, bidi_it
->charpos
,
1334 bidi_it
->string
.unibyte
);
1338 if (bidi_it
->charpos
< BEGV
)
1339 bidi_it
->charpos
= BEGV
;
1340 bidi_it
->bytepos
= CHAR_TO_BYTE (bidi_it
->charpos
);
1343 /* Don't move at end of buffer/string. */
1344 else if (bidi_it
->charpos
< (string_p
? bidi_it
->string
.schars
: ZV
))
1346 /* Advance to the next character, skipping characters covered by
1347 display strings (nchars > 1). */
1348 if (bidi_it
->nchars
<= 0)
1350 bidi_it
->charpos
+= bidi_it
->nchars
;
1351 if (bidi_it
->ch_len
== 0)
1353 bidi_it
->bytepos
+= bidi_it
->ch_len
;
1356 current_level
= bidi_it
->level_stack
[bidi_it
->stack_idx
].level
; /* X1 */
1357 override
= bidi_it
->level_stack
[bidi_it
->stack_idx
].override
;
1358 new_level
= current_level
;
1360 if (bidi_it
->charpos
>= (string_p
? bidi_it
->string
.schars
: ZV
))
1363 bidi_it
->ch_len
= 1;
1364 bidi_it
->nchars
= 1;
1365 bidi_it
->disp_pos
= (string_p
? bidi_it
->string
.schars
: ZV
);
1366 bidi_it
->disp_prop
= 0;
1370 /* Fetch the character at BYTEPOS. If it is covered by a
1371 display string, treat the entire run of covered characters as
1372 a single character u+FFFC. */
1373 curchar
= bidi_fetch_char (bidi_it
->bytepos
, bidi_it
->charpos
,
1374 &bidi_it
->disp_pos
, &bidi_it
->disp_prop
,
1375 &bidi_it
->string
, bidi_it
->frame_window_p
,
1376 &bidi_it
->ch_len
, &bidi_it
->nchars
);
1378 bidi_it
->ch
= curchar
;
1380 /* Don't apply directional override here, as all the types we handle
1381 below will not be affected by the override anyway, and we need
1382 the original type unaltered. The override will be applied in
1383 bidi_resolve_weak. */
1384 type
= bidi_get_type (curchar
, NEUTRAL_DIR
);
1385 bidi_it
->orig_type
= type
;
1386 bidi_check_type (bidi_it
->orig_type
);
1389 bidi_it
->prev_was_pdf
= 0;
1391 bidi_it
->type_after_w1
= UNKNOWN_BT
;
1397 bidi_it
->type_after_w1
= type
;
1398 bidi_check_type (bidi_it
->type_after_w1
);
1399 type
= WEAK_BN
; /* X9/Retaining */
1400 if (bidi_it
->ignore_bn_limit
<= -1)
1402 if (current_level
<= BIDI_MAXLEVEL
- 4)
1404 /* Compute the least odd embedding level greater than
1405 the current level. */
1406 new_level
= ((current_level
+ 1) & ~1) + 1;
1407 if (bidi_it
->type_after_w1
== RLE
)
1408 override
= NEUTRAL_DIR
;
1411 if (current_level
== BIDI_MAXLEVEL
- 4)
1412 bidi_it
->invalid_rl_levels
= 0;
1413 bidi_push_embedding_level (bidi_it
, new_level
, override
);
1417 bidi_it
->invalid_levels
++;
1418 /* See the commentary about invalid_rl_levels below. */
1419 if (bidi_it
->invalid_rl_levels
< 0)
1420 bidi_it
->invalid_rl_levels
= 0;
1421 bidi_it
->invalid_rl_levels
++;
1424 else if (bidi_it
->prev
.type_after_w1
== WEAK_EN
/* W5/Retaining */
1425 || bidi_it
->next_en_pos
> bidi_it
->charpos
)
1430 bidi_it
->type_after_w1
= type
;
1431 bidi_check_type (bidi_it
->type_after_w1
);
1432 type
= WEAK_BN
; /* X9/Retaining */
1433 if (bidi_it
->ignore_bn_limit
<= -1)
1435 if (current_level
<= BIDI_MAXLEVEL
- 5)
1437 /* Compute the least even embedding level greater than
1438 the current level. */
1439 new_level
= ((current_level
+ 2) & ~1);
1440 if (bidi_it
->type_after_w1
== LRE
)
1441 override
= NEUTRAL_DIR
;
1444 bidi_push_embedding_level (bidi_it
, new_level
, override
);
1448 bidi_it
->invalid_levels
++;
1449 /* invalid_rl_levels counts invalid levels encountered
1450 while the embedding level was already too high for
1451 LRE/LRO, but not for RLE/RLO. That is because
1452 there may be exactly one PDF which we should not
1453 ignore even though invalid_levels is non-zero.
1454 invalid_rl_levels helps to know what PDF is
1456 if (bidi_it
->invalid_rl_levels
>= 0)
1457 bidi_it
->invalid_rl_levels
++;
1460 else if (bidi_it
->prev
.type_after_w1
== WEAK_EN
/* W5/Retaining */
1461 || bidi_it
->next_en_pos
> bidi_it
->charpos
)
1465 bidi_it
->type_after_w1
= type
;
1466 bidi_check_type (bidi_it
->type_after_w1
);
1467 type
= WEAK_BN
; /* X9/Retaining */
1468 if (bidi_it
->ignore_bn_limit
<= -1)
1470 if (!bidi_it
->invalid_rl_levels
)
1472 new_level
= bidi_pop_embedding_level (bidi_it
);
1473 bidi_it
->invalid_rl_levels
= -1;
1474 if (bidi_it
->invalid_levels
)
1475 bidi_it
->invalid_levels
--;
1476 /* else nothing: UAX#9 says to ignore invalid PDFs */
1478 if (!bidi_it
->invalid_levels
)
1479 new_level
= bidi_pop_embedding_level (bidi_it
);
1482 bidi_it
->invalid_levels
--;
1483 bidi_it
->invalid_rl_levels
--;
1486 else if (bidi_it
->prev
.type_after_w1
== WEAK_EN
/* W5/Retaining */
1487 || bidi_it
->next_en_pos
> bidi_it
->charpos
)
1495 bidi_it
->type
= type
;
1496 bidi_check_type (bidi_it
->type
);
1501 /* Given an iterator state in BIDI_IT, advance one character position
1502 in the buffer/string to the next character (in the logical order),
1503 resolve any explicit embeddings and directional overrides, and
1504 return the embedding level of the character after resolving
1505 explicit directives and ignoring empty embeddings. */
1507 bidi_resolve_explicit (struct bidi_it
*bidi_it
)
1509 int prev_level
= bidi_it
->level_stack
[bidi_it
->stack_idx
].level
;
1510 int new_level
= bidi_resolve_explicit_1 (bidi_it
);
1511 EMACS_INT eob
= bidi_it
->string
.s
? bidi_it
->string
.schars
: ZV
;
1512 const unsigned char *s
= STRINGP (bidi_it
->string
.lstring
)
1513 ? SDATA (bidi_it
->string
.lstring
) : bidi_it
->string
.s
;
1515 if (prev_level
< new_level
1516 && bidi_it
->type
== WEAK_BN
1517 && bidi_it
->ignore_bn_limit
== -1 /* only if not already known */
1518 && bidi_it
->charpos
< eob
/* not already at EOB */
1519 && bidi_explicit_dir_char (bidi_char_at_pos (bidi_it
->bytepos
1520 + bidi_it
->ch_len
, s
,
1521 bidi_it
->string
.unibyte
)))
1523 /* Avoid pushing and popping embedding levels if the level run
1524 is empty, as this breaks level runs where it shouldn't.
1525 UAX#9 removes all the explicit embedding and override codes,
1526 so empty embeddings disappear without a trace. We need to
1527 behave as if we did the same. */
1528 struct bidi_it saved_it
;
1529 int level
= prev_level
;
1531 bidi_copy_it (&saved_it
, bidi_it
);
1533 while (bidi_explicit_dir_char (bidi_char_at_pos (bidi_it
->bytepos
1534 + bidi_it
->ch_len
, s
,
1535 bidi_it
->string
.unibyte
)))
1537 /* This advances to the next character, skipping any
1538 characters covered by display strings. */
1539 level
= bidi_resolve_explicit_1 (bidi_it
);
1540 /* If string.lstring was relocated inside bidi_resolve_explicit_1,
1541 a pointer to its data is no longer valid. */
1542 if (STRINGP (bidi_it
->string
.lstring
))
1543 s
= SDATA (bidi_it
->string
.lstring
);
1546 if (bidi_it
->nchars
<= 0)
1548 if (level
== prev_level
) /* empty embedding */
1549 saved_it
.ignore_bn_limit
= bidi_it
->charpos
+ bidi_it
->nchars
;
1550 else /* this embedding is non-empty */
1551 saved_it
.ignore_bn_limit
= -2;
1553 bidi_copy_it (bidi_it
, &saved_it
);
1554 if (bidi_it
->ignore_bn_limit
> -1)
1556 /* We pushed a level, but we shouldn't have. Undo that. */
1557 if (!bidi_it
->invalid_rl_levels
)
1559 new_level
= bidi_pop_embedding_level (bidi_it
);
1560 bidi_it
->invalid_rl_levels
= -1;
1561 if (bidi_it
->invalid_levels
)
1562 bidi_it
->invalid_levels
--;
1564 if (!bidi_it
->invalid_levels
)
1565 new_level
= bidi_pop_embedding_level (bidi_it
);
1568 bidi_it
->invalid_levels
--;
1569 bidi_it
->invalid_rl_levels
--;
1574 if (bidi_it
->type
== NEUTRAL_B
) /* X8 */
1576 bidi_set_paragraph_end (bidi_it
);
1577 /* This is needed by bidi_resolve_weak below, and in L1. */
1578 bidi_it
->type_after_w1
= bidi_it
->type
;
1579 bidi_check_type (bidi_it
->type_after_w1
);
1585 /* Advance in the buffer/string, resolve weak types and return the
1586 type of the next character after weak type resolution. */
1588 bidi_resolve_weak (struct bidi_it
*bidi_it
)
1591 bidi_dir_t override
;
1592 int prev_level
= bidi_it
->level_stack
[bidi_it
->stack_idx
].level
;
1593 int new_level
= bidi_resolve_explicit (bidi_it
);
1595 bidi_type_t type_of_next
;
1596 struct bidi_it saved_it
;
1598 (STRINGP (bidi_it
->string
.lstring
) || bidi_it
->string
.s
)
1599 ? bidi_it
->string
.schars
: ZV
;
1601 type
= bidi_it
->type
;
1602 override
= bidi_it
->level_stack
[bidi_it
->stack_idx
].override
;
1604 if (type
== UNKNOWN_BT
1612 if (new_level
!= prev_level
1613 || bidi_it
->type
== NEUTRAL_B
)
1615 /* We've got a new embedding level run, compute the directional
1616 type of sor and initialize per-run variables (UAX#9, clause
1618 bidi_set_sor_type (bidi_it
, prev_level
, new_level
);
1620 else if (type
== NEUTRAL_S
|| type
== NEUTRAL_WS
1621 || type
== WEAK_BN
|| type
== STRONG_AL
)
1622 bidi_it
->type_after_w1
= type
; /* needed in L1 */
1623 bidi_check_type (bidi_it
->type_after_w1
);
1625 /* Level and directional override status are already recorded in
1626 bidi_it, and do not need any change; see X6. */
1627 if (override
== R2L
) /* X6 */
1629 else if (override
== L2R
)
1633 if (type
== WEAK_NSM
) /* W1 */
1635 /* Note that we don't need to consider the case where the
1636 prev character has its type overridden by an RLO or LRO,
1637 because then either the type of this NSM would have been
1638 also overridden, or the previous character is outside the
1639 current level run, and thus not relevant to this NSM.
1640 This is why NSM gets the type_after_w1 of the previous
1642 if (bidi_it
->prev
.type_after_w1
!= UNKNOWN_BT
1643 /* if type_after_w1 is NEUTRAL_B, this NSM is at sor */
1644 && bidi_it
->prev
.type_after_w1
!= NEUTRAL_B
)
1645 type
= bidi_it
->prev
.type_after_w1
;
1646 else if (bidi_it
->sor
== R2L
)
1648 else if (bidi_it
->sor
== L2R
)
1650 else /* shouldn't happen! */
1653 if (type
== WEAK_EN
/* W2 */
1654 && bidi_it
->last_strong
.type_after_w1
== STRONG_AL
)
1656 else if (type
== STRONG_AL
) /* W3 */
1658 else if ((type
== WEAK_ES
/* W4 */
1659 && bidi_it
->prev
.type_after_w1
== WEAK_EN
1660 && bidi_it
->prev
.orig_type
== WEAK_EN
)
1662 && ((bidi_it
->prev
.type_after_w1
== WEAK_EN
1663 && bidi_it
->prev
.orig_type
== WEAK_EN
)
1664 || bidi_it
->prev
.type_after_w1
== WEAK_AN
)))
1666 const unsigned char *s
=
1667 STRINGP (bidi_it
->string
.lstring
)
1668 ? SDATA (bidi_it
->string
.lstring
) : bidi_it
->string
.s
;
1671 bidi_it
->charpos
+ bidi_it
->nchars
>= eob
1673 : bidi_char_at_pos (bidi_it
->bytepos
+ bidi_it
->ch_len
, s
,
1674 bidi_it
->string
.unibyte
);
1675 type_of_next
= bidi_get_type (next_char
, override
);
1677 if (type_of_next
== WEAK_BN
1678 || bidi_explicit_dir_char (next_char
))
1680 bidi_copy_it (&saved_it
, bidi_it
);
1681 while (bidi_resolve_explicit (bidi_it
) == new_level
1682 && bidi_it
->type
== WEAK_BN
)
1684 type_of_next
= bidi_it
->type
;
1685 bidi_copy_it (bidi_it
, &saved_it
);
1688 /* If the next character is EN, but the last strong-type
1689 character is AL, that next EN will be changed to AN when
1690 we process it in W2 above. So in that case, this ES
1691 should not be changed into EN. */
1693 && type_of_next
== WEAK_EN
1694 && bidi_it
->last_strong
.type_after_w1
!= STRONG_AL
)
1696 else if (type
== WEAK_CS
)
1698 if (bidi_it
->prev
.type_after_w1
== WEAK_AN
1699 && (type_of_next
== WEAK_AN
1700 /* If the next character is EN, but the last
1701 strong-type character is AL, EN will be later
1702 changed to AN when we process it in W2 above.
1703 So in that case, this ES should not be
1705 || (type_of_next
== WEAK_EN
1706 && bidi_it
->last_strong
.type_after_w1
== STRONG_AL
)))
1708 else if (bidi_it
->prev
.type_after_w1
== WEAK_EN
1709 && type_of_next
== WEAK_EN
1710 && bidi_it
->last_strong
.type_after_w1
!= STRONG_AL
)
1714 else if (type
== WEAK_ET
/* W5: ET with EN before or after it */
1715 || type
== WEAK_BN
) /* W5/Retaining */
1717 if (bidi_it
->prev
.type_after_w1
== WEAK_EN
/* ET/BN w/EN before it */
1718 || bidi_it
->next_en_pos
> bidi_it
->charpos
)
1720 else /* W5: ET/BN with EN after it. */
1722 EMACS_INT en_pos
= bidi_it
->charpos
+ bidi_it
->nchars
;
1723 const unsigned char *s
=
1724 STRINGP (bidi_it
->string
.lstring
)
1725 ? SDATA (bidi_it
->string
.lstring
) : bidi_it
->string
.s
;
1727 if (bidi_it
->nchars
<= 0)
1730 bidi_it
->charpos
+ bidi_it
->nchars
>= eob
1732 : bidi_char_at_pos (bidi_it
->bytepos
+ bidi_it
->ch_len
, s
,
1733 bidi_it
->string
.unibyte
);
1734 type_of_next
= bidi_get_type (next_char
, override
);
1736 if (type_of_next
== WEAK_ET
1737 || type_of_next
== WEAK_BN
1738 || bidi_explicit_dir_char (next_char
))
1740 bidi_copy_it (&saved_it
, bidi_it
);
1741 while (bidi_resolve_explicit (bidi_it
) == new_level
1742 && (bidi_it
->type
== WEAK_BN
1743 || bidi_it
->type
== WEAK_ET
))
1745 type_of_next
= bidi_it
->type
;
1746 en_pos
= bidi_it
->charpos
;
1747 bidi_copy_it (bidi_it
, &saved_it
);
1749 if (type_of_next
== WEAK_EN
)
1751 /* If the last strong character is AL, the EN we've
1752 found will become AN when we get to it (W2). */
1753 if (bidi_it
->last_strong
.type_after_w1
!= STRONG_AL
)
1756 /* Remember this EN position, to speed up processing
1758 bidi_it
->next_en_pos
= en_pos
;
1760 else if (type
== WEAK_BN
)
1761 type
= NEUTRAL_ON
; /* W6/Retaining */
1767 if (type
== WEAK_ES
|| type
== WEAK_ET
|| type
== WEAK_CS
/* W6 */
1769 && (bidi_it
->prev
.type_after_w1
== WEAK_CS
/* W6/Retaining */
1770 || bidi_it
->prev
.type_after_w1
== WEAK_ES
1771 || bidi_it
->prev
.type_after_w1
== WEAK_ET
)))
1774 /* Store the type we've got so far, before we clobber it with strong
1775 types in W7 and while resolving neutral types. But leave alone
1776 the original types that were recorded above, because we will need
1777 them for the L1 clause. */
1778 if (bidi_it
->type_after_w1
== UNKNOWN_BT
)
1779 bidi_it
->type_after_w1
= type
;
1780 bidi_check_type (bidi_it
->type_after_w1
);
1782 if (type
== WEAK_EN
) /* W7 */
1784 if ((bidi_it
->last_strong
.type_after_w1
== STRONG_L
)
1785 || (bidi_it
->last_strong
.type
== UNKNOWN_BT
&& bidi_it
->sor
== L2R
))
1789 bidi_it
->type
= type
;
1790 bidi_check_type (bidi_it
->type
);
1794 /* Resolve the type of a neutral character according to the type of
1795 surrounding strong text and the current embedding level. */
1796 static inline bidi_type_t
1797 bidi_resolve_neutral_1 (bidi_type_t prev_type
, bidi_type_t next_type
, int lev
)
1799 /* N1: European and Arabic numbers are treated as though they were R. */
1800 if (next_type
== WEAK_EN
|| next_type
== WEAK_AN
)
1801 next_type
= STRONG_R
;
1802 if (prev_type
== WEAK_EN
|| prev_type
== WEAK_AN
)
1803 prev_type
= STRONG_R
;
1805 if (next_type
== prev_type
) /* N1 */
1807 else if ((lev
& 1) == 0) /* N2 */
1814 bidi_resolve_neutral (struct bidi_it
*bidi_it
)
1816 int prev_level
= bidi_it
->level_stack
[bidi_it
->stack_idx
].level
;
1817 bidi_type_t type
= bidi_resolve_weak (bidi_it
);
1818 int current_level
= bidi_it
->level_stack
[bidi_it
->stack_idx
].level
;
1820 if (!(type
== STRONG_R
1825 || type
== NEUTRAL_B
1826 || type
== NEUTRAL_S
1827 || type
== NEUTRAL_WS
1828 || type
== NEUTRAL_ON
))
1831 if (bidi_get_category (type
) == NEUTRAL
1832 || (type
== WEAK_BN
&& prev_level
== current_level
))
1834 if (bidi_it
->next_for_neutral
.type
!= UNKNOWN_BT
)
1835 type
= bidi_resolve_neutral_1 (bidi_it
->prev_for_neutral
.type
,
1836 bidi_it
->next_for_neutral
.type
,
1840 /* Arrrgh!! The UAX#9 algorithm is too deeply entrenched in
1841 the assumption of batch-style processing; see clauses W4,
1842 W5, and especially N1, which require to look far forward
1843 (as well as back) in the buffer/string. May the fleas of
1844 a thousand camels infest the armpits of those who design
1845 supposedly general-purpose algorithms by looking at their
1846 own implementations, and fail to consider other possible
1848 struct bidi_it saved_it
;
1849 bidi_type_t next_type
;
1851 if (bidi_it
->scan_dir
== -1)
1854 bidi_copy_it (&saved_it
, bidi_it
);
1855 /* Scan the text forward until we find the first non-neutral
1856 character, and then use that to resolve the neutral we
1857 are dealing with now. We also cache the scanned iterator
1858 states, to salvage some of the effort later. */
1859 bidi_cache_iterator_state (bidi_it
, 0);
1861 /* Record the info about the previous character, so that
1862 it will be cached below with this state. */
1863 if (bidi_it
->type_after_w1
!= WEAK_BN
/* W1/Retaining */
1864 && bidi_it
->type
!= WEAK_BN
)
1865 bidi_remember_char (&bidi_it
->prev
, bidi_it
);
1866 type
= bidi_resolve_weak (bidi_it
);
1867 /* Paragraph separators have their levels fully resolved
1868 at this point, so cache them as resolved. */
1869 bidi_cache_iterator_state (bidi_it
, type
== NEUTRAL_B
);
1870 /* FIXME: implement L1 here, by testing for a newline and
1871 resetting the level for any sequence of whitespace
1872 characters adjacent to it. */
1873 } while (!(type
== NEUTRAL_B
1875 && bidi_get_category (type
) != NEUTRAL
)
1876 /* This is all per level run, so stop when we
1877 reach the end of this level run. */
1878 || bidi_it
->level_stack
[bidi_it
->stack_idx
].level
!=
1881 bidi_remember_char (&saved_it
.next_for_neutral
, bidi_it
);
1892 /* N1: ``European and Arabic numbers are treated as
1893 though they were R.'' */
1894 next_type
= STRONG_R
;
1895 saved_it
.next_for_neutral
.type
= STRONG_R
;
1898 if (!bidi_explicit_dir_char (bidi_it
->ch
))
1899 abort (); /* can't happen: BNs are skipped */
1902 /* Marched all the way to the end of this level run.
1903 We need to use the eor type, whose information is
1904 stored by bidi_set_sor_type in the prev_for_neutral
1906 if (saved_it
.type
!= WEAK_BN
1907 || bidi_get_category (bidi_it
->prev
.type_after_w1
) == NEUTRAL
)
1909 next_type
= bidi_it
->prev_for_neutral
.type
;
1910 saved_it
.next_for_neutral
.type
= next_type
;
1911 bidi_check_type (next_type
);
1915 /* This is a BN which does not adjoin neutrals.
1916 Leave its type alone. */
1917 bidi_copy_it (bidi_it
, &saved_it
);
1918 return bidi_it
->type
;
1924 type
= bidi_resolve_neutral_1 (saved_it
.prev_for_neutral
.type
,
1925 next_type
, current_level
);
1926 saved_it
.type
= type
;
1927 bidi_check_type (type
);
1928 bidi_copy_it (bidi_it
, &saved_it
);
1934 /* Given an iterator state in BIDI_IT, advance one character position
1935 in the buffer/string to the next character (in the logical order),
1936 resolve the bidi type of that next character, and return that
1939 bidi_type_of_next_char (struct bidi_it
*bidi_it
)
1943 /* This should always be called during a forward scan. */
1944 if (bidi_it
->scan_dir
!= 1)
1947 /* Reset the limit until which to ignore BNs if we step out of the
1948 area where we found only empty levels. */
1949 if ((bidi_it
->ignore_bn_limit
> -1
1950 && bidi_it
->ignore_bn_limit
<= bidi_it
->charpos
)
1951 || (bidi_it
->ignore_bn_limit
== -2
1952 && !bidi_explicit_dir_char (bidi_it
->ch
)))
1953 bidi_it
->ignore_bn_limit
= -1;
1955 type
= bidi_resolve_neutral (bidi_it
);
1960 /* Given an iterator state BIDI_IT, advance one character position in
1961 the buffer/string to the next character (in the current scan
1962 direction), resolve the embedding and implicit levels of that next
1963 character, and return the resulting level. */
1965 bidi_level_of_next_char (struct bidi_it
*bidi_it
)
1968 int level
, prev_level
= -1;
1969 struct bidi_saved_info next_for_neutral
;
1970 EMACS_INT next_char_pos
= -2;
1972 if (bidi_it
->scan_dir
== 1)
1975 (bidi_it
->string
.s
|| STRINGP (bidi_it
->string
.lstring
))
1976 ? bidi_it
->string
.schars
: ZV
;
1978 /* There's no sense in trying to advance if we hit end of text. */
1979 if (bidi_it
->charpos
>= eob
)
1980 return bidi_it
->resolved_level
;
1982 /* Record the info about the previous character. */
1983 if (bidi_it
->type_after_w1
!= WEAK_BN
/* W1/Retaining */
1984 && bidi_it
->type
!= WEAK_BN
)
1985 bidi_remember_char (&bidi_it
->prev
, bidi_it
);
1986 if (bidi_it
->type_after_w1
== STRONG_R
1987 || bidi_it
->type_after_w1
== STRONG_L
1988 || bidi_it
->type_after_w1
== STRONG_AL
)
1989 bidi_remember_char (&bidi_it
->last_strong
, bidi_it
);
1990 /* FIXME: it sounds like we don't need both prev and
1991 prev_for_neutral members, but I'm leaving them both for now. */
1992 if (bidi_it
->type
== STRONG_R
|| bidi_it
->type
== STRONG_L
1993 || bidi_it
->type
== WEAK_EN
|| bidi_it
->type
== WEAK_AN
)
1994 bidi_remember_char (&bidi_it
->prev_for_neutral
, bidi_it
);
1996 /* If we overstepped the characters used for resolving neutrals
1997 and whitespace, invalidate their info in the iterator. */
1998 if (bidi_it
->charpos
>= bidi_it
->next_for_neutral
.charpos
)
1999 bidi_it
->next_for_neutral
.type
= UNKNOWN_BT
;
2000 if (bidi_it
->next_en_pos
>= 0
2001 && bidi_it
->charpos
>= bidi_it
->next_en_pos
)
2002 bidi_it
->next_en_pos
= -1;
2003 if (bidi_it
->next_for_ws
.type
!= UNKNOWN_BT
2004 && bidi_it
->charpos
>= bidi_it
->next_for_ws
.charpos
)
2005 bidi_it
->next_for_ws
.type
= UNKNOWN_BT
;
2007 /* This must be taken before we fill the iterator with the info
2008 about the next char. If we scan backwards, the iterator
2009 state must be already cached, so there's no need to know the
2010 embedding level of the previous character, since we will be
2011 returning to our caller shortly. */
2012 prev_level
= bidi_it
->level_stack
[bidi_it
->stack_idx
].level
;
2014 next_for_neutral
= bidi_it
->next_for_neutral
;
2016 /* Perhaps the character we want is already cached. If it is, the
2017 call to bidi_cache_find below will return a type other than
2019 if (bidi_cache_idx
> bidi_cache_start
&& !bidi_it
->first_elt
)
2022 (bidi_it
->string
.s
|| STRINGP (bidi_it
->string
.lstring
)) ? 0 : 1;
2024 if (bidi_it
->scan_dir
> 0)
2026 if (bidi_it
->nchars
<= 0)
2028 next_char_pos
= bidi_it
->charpos
+ bidi_it
->nchars
;
2030 else if (bidi_it
->charpos
>= bob
)
2031 /* Implementation note: we allow next_char_pos to be as low as
2032 0 for buffers or -1 for strings, and that is okay because
2033 that's the "position" of the sentinel iterator state we
2034 cached at the beginning of the iteration. */
2035 next_char_pos
= bidi_it
->charpos
- 1;
2036 if (next_char_pos
>= bob
- 1)
2037 type
= bidi_cache_find (next_char_pos
, -1, bidi_it
);
2043 if (type
!= UNKNOWN_BT
)
2045 /* Don't lose the information for resolving neutrals! The
2046 cached states could have been cached before their
2047 next_for_neutral member was computed. If we are on our way
2048 forward, we can simply take the info from the previous
2050 if (bidi_it
->scan_dir
== 1
2051 && bidi_it
->next_for_neutral
.type
== UNKNOWN_BT
)
2052 bidi_it
->next_for_neutral
= next_for_neutral
;
2054 /* If resolved_level is -1, it means this state was cached
2055 before it was completely resolved, so we cannot return
2057 if (bidi_it
->resolved_level
!= -1)
2058 return bidi_it
->resolved_level
;
2060 if (bidi_it
->scan_dir
== -1)
2061 /* If we are going backwards, the iterator state is already cached
2062 from previous scans, and should be fully resolved. */
2065 if (type
== UNKNOWN_BT
)
2066 type
= bidi_type_of_next_char (bidi_it
);
2068 if (type
== NEUTRAL_B
)
2069 return bidi_it
->resolved_level
;
2071 level
= bidi_it
->level_stack
[bidi_it
->stack_idx
].level
;
2072 if ((bidi_get_category (type
) == NEUTRAL
/* && type != NEUTRAL_B */)
2073 || (type
== WEAK_BN
&& prev_level
== level
))
2075 if (bidi_it
->next_for_neutral
.type
== UNKNOWN_BT
)
2078 /* If the cached state shows a neutral character, it was not
2079 resolved by bidi_resolve_neutral, so do it now. */
2080 type
= bidi_resolve_neutral_1 (bidi_it
->prev_for_neutral
.type
,
2081 bidi_it
->next_for_neutral
.type
,
2085 if (!(type
== STRONG_R
2089 || type
== WEAK_AN
))
2091 bidi_it
->type
= type
;
2092 bidi_check_type (bidi_it
->type
);
2094 /* For L1 below, we need to know, for each WS character, whether
2095 it belongs to a sequence of WS characters preceding a newline
2096 or a TAB or a paragraph separator. */
2097 if (bidi_it
->orig_type
== NEUTRAL_WS
2098 && bidi_it
->next_for_ws
.type
== UNKNOWN_BT
)
2101 EMACS_INT clen
= bidi_it
->ch_len
;
2102 EMACS_INT bpos
= bidi_it
->bytepos
;
2103 EMACS_INT cpos
= bidi_it
->charpos
;
2104 EMACS_INT disp_pos
= bidi_it
->disp_pos
;
2105 EMACS_INT nc
= bidi_it
->nchars
;
2106 struct bidi_string_data bs
= bidi_it
->string
;
2108 int fwp
= bidi_it
->frame_window_p
;
2109 int dpp
= bidi_it
->disp_prop
;
2111 if (bidi_it
->nchars
<= 0)
2114 ch
= bidi_fetch_char (bpos
+= clen
, cpos
+= nc
, &disp_pos
, &dpp
, &bs
,
2116 if (ch
== '\n' || ch
== BIDI_EOB
/* || ch == LINESEP_CHAR */)
2119 chtype
= bidi_get_type (ch
, NEUTRAL_DIR
);
2120 } while (chtype
== NEUTRAL_WS
|| chtype
== WEAK_BN
2121 || bidi_explicit_dir_char (ch
)); /* L1/Retaining */
2122 bidi_it
->next_for_ws
.type
= chtype
;
2123 bidi_check_type (bidi_it
->next_for_ws
.type
);
2124 bidi_it
->next_for_ws
.charpos
= cpos
;
2125 bidi_it
->next_for_ws
.bytepos
= bpos
;
2128 /* Resolve implicit levels, with a twist: PDFs get the embedding
2129 level of the enbedding they terminate. See below for the
2131 if (bidi_it
->orig_type
== PDF
2132 /* Don't do this if this formatting code didn't change the
2133 embedding level due to invalid or empty embeddings. */
2134 && prev_level
!= level
)
2136 /* Don't look in UAX#9 for the reason for this: it's our own
2137 private quirk. The reason is that we want the formatting
2138 codes to be delivered so that they bracket the text of their
2139 embedding. For example, given the text
2143 we want it to be displayed as
2151 which will result because we bump up the embedding level as
2152 soon as we see the RLO and pop it as soon as we see the PDF,
2153 so RLO itself has the same embedding level as "teST", and
2154 thus would be normally delivered last, just before the PDF.
2155 The switch below fiddles with the level of PDF so that this
2156 ugly side effect does not happen.
2158 (This is, of course, only important if the formatting codes
2159 are actually displayed, but Emacs does need to display them
2160 if the user wants to.) */
2163 else if (bidi_it
->orig_type
== NEUTRAL_B
/* L1 */
2164 || bidi_it
->orig_type
== NEUTRAL_S
2165 || bidi_it
->ch
== '\n' || bidi_it
->ch
== BIDI_EOB
2166 /* || bidi_it->ch == LINESEP_CHAR */
2167 || (bidi_it
->orig_type
== NEUTRAL_WS
2168 && (bidi_it
->next_for_ws
.type
== NEUTRAL_B
2169 || bidi_it
->next_for_ws
.type
== NEUTRAL_S
)))
2170 level
= bidi_it
->level_stack
[0].level
;
2171 else if ((level
& 1) == 0) /* I1 */
2173 if (type
== STRONG_R
)
2175 else if (type
== WEAK_EN
|| type
== WEAK_AN
)
2180 if (type
== STRONG_L
|| type
== WEAK_EN
|| type
== WEAK_AN
)
2184 bidi_it
->resolved_level
= level
;
2188 /* Move to the other edge of a level given by LEVEL. If END_FLAG is
2189 non-zero, we are at the end of a level, and we need to prepare to
2190 resume the scan of the lower level.
2192 If this level's other edge is cached, we simply jump to it, filling
2193 the iterator structure with the iterator state on the other edge.
2194 Otherwise, we walk the buffer or string until we come back to the
2195 same level as LEVEL.
2197 Note: we are not talking here about a ``level run'' in the UAX#9
2198 sense of the term, but rather about a ``level'' which includes
2199 all the levels higher than it. In other words, given the levels
2202 11111112222222333333334443343222222111111112223322111
2205 and assuming we are at point A scanning left to right, this
2206 function moves to point C, whereas the UAX#9 ``level 2 run'' ends
2209 bidi_find_other_level_edge (struct bidi_it
*bidi_it
, int level
, int end_flag
)
2211 int dir
= end_flag
? -bidi_it
->scan_dir
: bidi_it
->scan_dir
;
2214 /* Try the cache first. */
2215 if ((idx
= bidi_cache_find_level_change (level
, dir
, end_flag
))
2216 >= bidi_cache_start
)
2217 bidi_cache_fetch_state (idx
, bidi_it
);
2223 abort (); /* if we are at end of level, its edges must be cached */
2225 bidi_cache_iterator_state (bidi_it
, 1);
2227 new_level
= bidi_level_of_next_char (bidi_it
);
2228 bidi_cache_iterator_state (bidi_it
, 1);
2229 } while (new_level
>= level
);
2234 bidi_move_to_visually_next (struct bidi_it
*bidi_it
)
2236 int old_level
, new_level
, next_level
;
2237 struct bidi_it sentinel
;
2238 struct gcpro gcpro1
;
2240 if (bidi_it
->charpos
< 0 || bidi_it
->bytepos
< 0)
2243 if (bidi_it
->scan_dir
== 0)
2245 bidi_it
->scan_dir
= 1; /* default to logical order */
2248 /* The code below can call eval, and thus cause GC. If we are
2249 iterating a Lisp string, make sure it won't be GCed. */
2250 if (STRINGP (bidi_it
->string
.lstring
))
2251 GCPRO1 (bidi_it
->string
.lstring
);
2253 /* If we just passed a newline, initialize for the next line. */
2254 if (!bidi_it
->first_elt
2255 && (bidi_it
->ch
== '\n' || bidi_it
->ch
== BIDI_EOB
))
2256 bidi_line_init (bidi_it
);
2258 /* Prepare the sentinel iterator state, and cache it. When we bump
2259 into it, scanning backwards, we'll know that the last non-base
2260 level is exhausted. */
2261 if (bidi_cache_idx
== bidi_cache_start
)
2263 bidi_copy_it (&sentinel
, bidi_it
);
2264 if (bidi_it
->first_elt
)
2266 sentinel
.charpos
--; /* cached charpos needs to be monotonic */
2268 sentinel
.ch
= '\n'; /* doesn't matter, but why not? */
2269 sentinel
.ch_len
= 1;
2270 sentinel
.nchars
= 1;
2272 bidi_cache_iterator_state (&sentinel
, 1);
2275 old_level
= bidi_it
->resolved_level
;
2276 new_level
= bidi_level_of_next_char (bidi_it
);
2278 /* Reordering of resolved levels (clause L2) is implemented by
2279 jumping to the other edge of the level and flipping direction of
2280 scanning the text whenever we find a level change. */
2281 if (new_level
!= old_level
)
2283 int ascending
= new_level
> old_level
;
2284 int level_to_search
= ascending
? old_level
+ 1 : old_level
;
2285 int incr
= ascending
? 1 : -1;
2286 int expected_next_level
= old_level
+ incr
;
2288 /* Jump (or walk) to the other edge of this level. */
2289 bidi_find_other_level_edge (bidi_it
, level_to_search
, !ascending
);
2290 /* Switch scan direction and peek at the next character in the
2292 bidi_it
->scan_dir
= -bidi_it
->scan_dir
;
2294 /* The following loop handles the case where the resolved level
2295 jumps by more than one. This is typical for numbers inside a
2296 run of text with left-to-right embedding direction, but can
2297 also happen in other situations. In those cases the decision
2298 where to continue after a level change, and in what direction,
2299 is tricky. For example, given a text like below:
2304 (where the numbers below the text show the resolved levels),
2305 the result of reordering according to UAX#9 should be this:
2309 This is implemented by the loop below which flips direction
2310 and jumps to the other edge of the level each time it finds
2311 the new level not to be the expected one. The expected level
2312 is always one more or one less than the previous one. */
2313 next_level
= bidi_peek_at_next_level (bidi_it
);
2314 while (next_level
!= expected_next_level
)
2316 expected_next_level
+= incr
;
2317 level_to_search
+= incr
;
2318 bidi_find_other_level_edge (bidi_it
, level_to_search
, !ascending
);
2319 bidi_it
->scan_dir
= -bidi_it
->scan_dir
;
2320 next_level
= bidi_peek_at_next_level (bidi_it
);
2323 /* Finally, deliver the next character in the new direction. */
2324 next_level
= bidi_level_of_next_char (bidi_it
);
2327 /* Take note when we have just processed the newline that precedes
2328 the end of the paragraph. The next time we are about to be
2329 called, set_iterator_to_next will automatically reinit the
2330 paragraph direction, if needed. We do this at the newline before
2331 the paragraph separator, because the next character might not be
2332 the first character of the next paragraph, due to the bidi
2333 reordering, whereas we _must_ know the paragraph base direction
2334 _before_ we process the paragraph's text, since the base
2335 direction affects the reordering. */
2336 if (bidi_it
->scan_dir
== 1
2337 && (bidi_it
->ch
== '\n' || bidi_it
->ch
== BIDI_EOB
))
2339 /* The paragraph direction of the entire string, once
2340 determined, is in effect for the entire string. Setting the
2341 separator limit to the end of the string prevents
2342 bidi_paragraph_init from being called automatically on this
2344 if (bidi_it
->string
.s
|| STRINGP (bidi_it
->string
.lstring
))
2345 bidi_it
->separator_limit
= bidi_it
->string
.schars
;
2346 else if (bidi_it
->bytepos
< ZV_BYTE
)
2349 bidi_at_paragraph_end (bidi_it
->charpos
+ bidi_it
->nchars
,
2350 bidi_it
->bytepos
+ bidi_it
->ch_len
);
2351 if (bidi_it
->nchars
<= 0)
2355 bidi_it
->new_paragraph
= 1;
2356 /* Record the buffer position of the last character of the
2357 paragraph separator. */
2358 bidi_it
->separator_limit
=
2359 bidi_it
->charpos
+ bidi_it
->nchars
+ sep_len
;
2364 if (bidi_it
->scan_dir
== 1 && bidi_cache_idx
> bidi_cache_start
)
2366 /* If we are at paragraph's base embedding level and beyond the
2367 last cached position, the cache's job is done and we can
2369 if (bidi_it
->resolved_level
== bidi_it
->level_stack
[0].level
2370 && bidi_it
->charpos
> (bidi_cache
[bidi_cache_idx
- 1].charpos
2371 + bidi_cache
[bidi_cache_idx
- 1].nchars
- 1))
2372 bidi_cache_reset ();
2373 /* But as long as we are caching during forward scan, we must
2374 cache each state, or else the cache integrity will be
2375 compromised: it assumes cached states correspond to buffer
2378 bidi_cache_iterator_state (bidi_it
, 1);
2381 if (STRINGP (bidi_it
->string
.lstring
))
2385 /* This is meant to be called from within the debugger, whenever you
2386 wish to examine the cache contents. */
2387 void bidi_dump_cached_states (void) EXTERNALLY_VISIBLE
;
2389 bidi_dump_cached_states (void)
2394 if (bidi_cache_idx
== 0)
2396 fprintf (stderr
, "The cache is empty.\n");
2399 fprintf (stderr
, "Total of %"pD
"d state%s in cache:\n",
2400 bidi_cache_idx
, bidi_cache_idx
== 1 ? "" : "s");
2402 for (i
= bidi_cache
[bidi_cache_idx
- 1].charpos
; i
> 0; i
/= 10)
2404 fputs ("ch ", stderr
);
2405 for (i
= 0; i
< bidi_cache_idx
; i
++)
2406 fprintf (stderr
, "%*c", ndigits
, bidi_cache
[i
].ch
);
2407 fputs ("\n", stderr
);
2408 fputs ("lvl ", stderr
);
2409 for (i
= 0; i
< bidi_cache_idx
; i
++)
2410 fprintf (stderr
, "%*d", ndigits
, bidi_cache
[i
].resolved_level
);
2411 fputs ("\n", stderr
);
2412 fputs ("pos ", stderr
);
2413 for (i
= 0; i
< bidi_cache_idx
; i
++)
2414 fprintf (stderr
, "%*"pI
"d", ndigits
, bidi_cache
[i
].charpos
);
2415 fputs ("\n", stderr
);