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[emacs.git] / src / indent.c
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1 /* Indentation functions.
2 Copyright (C) 1985,86,87,88,93,94,95 Free Software Foundation, Inc.
4 This file is part of GNU Emacs.
6 GNU Emacs is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
9 any later version.
11 GNU Emacs is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GNU Emacs; see the file COPYING. If not, write to
18 the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
19 Boston, MA 02111-1307, USA. */
22 #include <config.h>
23 #include "lisp.h"
24 #include "buffer.h"
25 #include "charset.h"
26 #include "indent.h"
27 #include "frame.h"
28 #include "window.h"
29 #include "termchar.h"
30 #include "termopts.h"
31 #include "disptab.h"
32 #include "intervals.h"
33 #include "region-cache.h"
35 /* Indentation can insert tabs if this is non-zero;
36 otherwise always uses spaces */
37 int indent_tabs_mode;
39 #define min(a, b) ((a) < (b) ? (a) : (b))
40 #define max(a, b) ((a) > (b) ? (a) : (b))
42 #define CR 015
44 /* These three values memoize the current column to avoid recalculation */
45 /* Some things in set last_known_column_point to -1
46 to mark the memoized value as invalid */
47 /* Last value returned by current_column */
48 int last_known_column;
49 /* Value of point when current_column was called */
50 int last_known_column_point;
51 /* Value of MODIFF when current_column was called */
52 int last_known_column_modified;
54 static int current_column_1 ();
56 /* Cache of beginning of line found by the last call of
57 current_column. */
58 int current_column_bol_cache;
60 /* Get the display table to use for the current buffer. */
62 struct Lisp_Char_Table *
63 buffer_display_table ()
65 Lisp_Object thisbuf;
67 thisbuf = current_buffer->display_table;
68 if (DISP_TABLE_P (thisbuf))
69 return XCHAR_TABLE (thisbuf);
70 if (DISP_TABLE_P (Vstandard_display_table))
71 return XCHAR_TABLE (Vstandard_display_table);
72 return 0;
75 /* Width run cache considerations. */
77 /* Return the width of character C under display table DP. */
79 static int
80 character_width (c, dp)
81 int c;
82 struct Lisp_Char_Table *dp;
84 Lisp_Object elt;
86 /* These width computations were determined by examining the cases
87 in display_text_line. */
89 /* Everything can be handled by the display table, if it's
90 present and the element is right. */
91 if (dp && (elt = DISP_CHAR_VECTOR (dp, c), VECTORP (elt)))
92 return XVECTOR (elt)->size;
94 /* Some characters are special. */
95 if (c == '\n' || c == '\t' || c == '\015')
96 return 0;
98 /* Printing characters have width 1. */
99 else if (c >= 040 && c < 0177)
100 return 1;
102 /* Everybody else (control characters, metacharacters) has other
103 widths. We could return their actual widths here, but they
104 depend on things like ctl_arrow and crud like that, and they're
105 not very common at all. So we'll just claim we don't know their
106 widths. */
107 else
108 return 0;
111 /* Return true iff the display table DISPTAB specifies the same widths
112 for characters as WIDTHTAB. We use this to decide when to
113 invalidate the buffer's width_run_cache. */
115 disptab_matches_widthtab (disptab, widthtab)
116 struct Lisp_Char_Table *disptab;
117 struct Lisp_Vector *widthtab;
119 int i;
121 if (widthtab->size != 256)
122 abort ();
124 for (i = 0; i < 256; i++)
125 if (character_width (i, disptab)
126 != XFASTINT (widthtab->contents[i]))
127 return 0;
129 return 1;
132 /* Recompute BUF's width table, using the display table DISPTAB. */
133 void
134 recompute_width_table (buf, disptab)
135 struct buffer *buf;
136 struct Lisp_Char_Table *disptab;
138 int i;
139 struct Lisp_Vector *widthtab;
141 if (!VECTORP (buf->width_table))
142 buf->width_table = Fmake_vector (make_number (256), make_number (0));
143 widthtab = XVECTOR (buf->width_table);
144 if (widthtab->size != 256)
145 abort ();
147 for (i = 0; i < 256; i++)
148 XSETFASTINT (widthtab->contents[i], character_width (i, disptab));
151 /* Allocate or free the width run cache, as requested by the current
152 state of current_buffer's cache_long_line_scans variable. */
153 static void
154 width_run_cache_on_off ()
156 if (NILP (current_buffer->cache_long_line_scans)
157 /* And, for the moment, this feature doesn't work on multibyte
158 characters. */
159 || !NILP (current_buffer->enable_multibyte_characters))
161 /* It should be off. */
162 if (current_buffer->width_run_cache)
164 free_region_cache (current_buffer->width_run_cache);
165 current_buffer->width_run_cache = 0;
166 current_buffer->width_table = Qnil;
169 else
171 /* It should be on. */
172 if (current_buffer->width_run_cache == 0)
174 current_buffer->width_run_cache = new_region_cache ();
175 recompute_width_table (current_buffer, buffer_display_table ());
181 /* Skip some invisible characters starting from POS.
182 This includes characters invisible because of text properties
183 and characters invisible because of overlays.
185 If position POS is followed by invisible characters,
186 skip some of them and return the position after them.
187 Otherwise return POS itself.
189 Set *NEXT_BOUNDARY_P to the next position at which
190 it will be necessary to call this function again.
192 Don't scan past TO, and don't set *NEXT_BOUNDARY_P
193 to a value greater than TO.
195 If WINDOW is non-nil, and this buffer is displayed in WINDOW,
196 take account of overlays that apply only in WINDOW.
198 We don't necessarily skip all the invisible characters after POS
199 because that could take a long time. We skip a reasonable number
200 which can be skipped quickly. If there might be more invisible
201 characters immediately following, then *NEXT_BOUNDARY_P
202 will equal the return value. */
204 static int
205 skip_invisible (pos, next_boundary_p, to, window)
206 int pos;
207 int *next_boundary_p;
208 int to;
209 Lisp_Object window;
211 Lisp_Object prop, position, overlay_limit, proplimit;
212 Lisp_Object buffer;
213 int end;
215 XSETFASTINT (position, pos);
216 XSETBUFFER (buffer, current_buffer);
218 /* Give faster response for overlay lookup near POS. */
219 recenter_overlay_lists (current_buffer, pos);
221 /* We must not advance farther than the next overlay change.
222 The overlay change might change the invisible property;
223 or there might be overlay strings to be displayed there. */
224 overlay_limit = Fnext_overlay_change (position);
225 /* As for text properties, this gives a lower bound
226 for where the invisible text property could change. */
227 proplimit = Fnext_property_change (position, buffer, Qt);
228 if (XFASTINT (overlay_limit) < XFASTINT (proplimit))
229 proplimit = overlay_limit;
230 /* PROPLIMIT is now a lower bound for the next change
231 in invisible status. If that is plenty far away,
232 use that lower bound. */
233 if (XFASTINT (proplimit) > pos + 100 || XFASTINT (proplimit) >= to)
234 *next_boundary_p = XFASTINT (proplimit);
235 /* Otherwise, scan for the next `invisible' property change. */
236 else
238 /* Don't scan terribly far. */
239 XSETFASTINT (proplimit, min (pos + 100, to));
240 /* No matter what. don't go past next overlay change. */
241 if (XFASTINT (overlay_limit) < XFASTINT (proplimit))
242 proplimit = overlay_limit;
243 end = XFASTINT (Fnext_single_property_change (position, Qinvisible,
244 buffer, proplimit));
245 /* Don't put the boundary in the middle of multibyte form if
246 there is no actual property change. */
247 if (end == pos + 100
248 && !NILP (current_buffer->enable_multibyte_characters)
249 && end < ZV)
250 while (pos < end && !CHAR_HEAD_P (POS_ADDR (end)))
251 end--;
252 *next_boundary_p = end;
254 /* if the `invisible' property is set, we can skip to
255 the next property change */
256 if (!NILP (window) && EQ (XWINDOW (window)->buffer, buffer))
257 prop = Fget_char_property (position, Qinvisible, window);
258 else
259 prop = Fget_char_property (position, Qinvisible, buffer);
260 if (TEXT_PROP_MEANS_INVISIBLE (prop))
261 return *next_boundary_p;
262 return pos;
265 DEFUN ("current-column", Fcurrent_column, Scurrent_column, 0, 0, 0,
266 "Return the horizontal position of point. Beginning of line is column 0.\n\
267 This is calculated by adding together the widths of all the displayed\n\
268 representations of the character between the start of the previous line\n\
269 and point. (eg control characters will have a width of 2 or 4, tabs\n\
270 will have a variable width)\n\
271 Ignores finite width of frame, which means that this function may return\n\
272 values greater than (frame-width).\n\
273 Whether the line is visible (if `selective-display' is t) has no effect;\n\
274 however, ^M is treated as end of line when `selective-display' is t.")
277 Lisp_Object temp;
278 XSETFASTINT (temp, current_column ());
279 return temp;
282 /* Cancel any recorded value of the horizontal position. */
284 invalidate_current_column ()
286 last_known_column_point = 0;
290 current_column ()
292 register int col;
293 register unsigned char *ptr, *stop;
294 register int tab_seen;
295 int post_tab;
296 register int c;
297 register int tab_width = XINT (current_buffer->tab_width);
298 int ctl_arrow = !NILP (current_buffer->ctl_arrow);
299 register struct Lisp_Char_Table *dp = buffer_display_table ();
300 int stopchar;
302 if (PT == last_known_column_point
303 && MODIFF == last_known_column_modified)
304 return last_known_column;
306 /* If the buffer has overlays, text properties, or multibyte,
307 use a more general algorithm. */
308 if (BUF_INTERVALS (current_buffer)
309 || !NILP (current_buffer->overlays_before)
310 || !NILP (current_buffer->overlays_after)
311 || !NILP (current_buffer->enable_multibyte_characters))
312 return current_column_1 (PT);
314 /* Scan backwards from point to the previous newline,
315 counting width. Tab characters are the only complicated case. */
317 /* Make a pointer for decrementing through the chars before point. */
318 ptr = POS_ADDR (PT - 1) + 1;
319 /* Make a pointer to where consecutive chars leave off,
320 going backwards from point. */
321 if (PT == BEGV)
322 stop = ptr;
323 else if (PT <= GPT || BEGV > GPT)
324 stop = BEGV_ADDR;
325 else
326 stop = GAP_END_ADDR;
328 if (tab_width <= 0 || tab_width > 1000) tab_width = 8;
330 col = 0, tab_seen = 0, post_tab = 0;
332 while (1)
334 if (ptr == stop)
336 /* We stopped either for the beginning of the buffer
337 or for the gap. */
338 if (ptr == BEGV_ADDR)
339 break;
340 /* It was the gap. Jump back over it. */
341 stop = BEGV_ADDR;
342 ptr = GPT_ADDR;
343 /* Check whether that brings us to beginning of buffer. */
344 if (BEGV >= GPT) break;
347 c = *--ptr;
348 if (dp != 0 && VECTORP (DISP_CHAR_VECTOR (dp, c)))
349 col += XVECTOR (DISP_CHAR_VECTOR (dp, c))->size;
350 else if (c >= 040 && c < 0177)
351 col++;
352 else if (c == '\n'
353 || (c == '\r' && EQ (current_buffer->selective_display, Qt)))
355 ptr++;
356 break;
358 else if (c == '\t')
360 if (tab_seen)
361 col = ((col + tab_width) / tab_width) * tab_width;
363 post_tab += col;
364 col = 0;
365 tab_seen = 1;
367 else
368 col += (ctl_arrow && c < 0200) ? 2 : 4;
371 if (tab_seen)
373 col = ((col + tab_width) / tab_width) * tab_width;
374 col += post_tab;
377 if (ptr == BEGV_ADDR)
378 current_column_bol_cache = BEGV;
379 else
380 current_column_bol_cache = PTR_CHAR_POS (ptr);
381 last_known_column = col;
382 last_known_column_point = PT;
383 last_known_column_modified = MODIFF;
385 return col;
388 /* Return the column number of position POS
389 by scanning forward from the beginning of the line.
390 This function handles characters that are invisible
391 due to text properties or overlays. */
393 static int
394 current_column_1 (pos)
395 int pos;
397 register int tab_width = XINT (current_buffer->tab_width);
398 register int ctl_arrow = !NILP (current_buffer->ctl_arrow);
399 register struct Lisp_Char_Table *dp = buffer_display_table ();
401 /* Start the scan at the beginning of this line with column number 0. */
402 register int col = 0;
403 int scan = current_column_bol_cache = find_next_newline (pos, -1);
404 int next_boundary = scan;
405 int multibyte = !NILP (current_buffer->enable_multibyte_characters);
407 if (tab_width <= 0 || tab_width > 1000) tab_width = 8;
409 /* Scan forward to the target position. */
410 while (scan < pos)
412 int c;
414 /* Occasionally we may need to skip invisible text. */
415 while (scan == next_boundary)
417 /* This updates NEXT_BOUNDARY to the next place
418 where we might need to skip more invisible text. */
419 scan = skip_invisible (scan, &next_boundary, pos, Qnil);
420 if (scan >= pos)
421 goto endloop;
424 c = FETCH_BYTE (scan);
425 if (dp != 0 && VECTORP (DISP_CHAR_VECTOR (dp, c)))
427 col += XVECTOR (DISP_CHAR_VECTOR (dp, c))->size;
428 scan++;
429 continue;
431 if (c == '\n')
432 break;
433 if (c == '\r' && EQ (current_buffer->selective_display, Qt))
434 break;
435 scan++;
436 if (c == '\t')
438 int prev_col = col;
439 col += tab_width;
440 col = col / tab_width * tab_width;
442 else if (multibyte && BASE_LEADING_CODE_P (c))
444 scan--;
445 /* Start of multi-byte form. */
446 if (c == LEADING_CODE_COMPOSITION)
448 unsigned char *ptr = POS_ADDR (scan);
450 int cmpchar_id = str_cmpchar_id (ptr, next_boundary - scan);
451 if (cmpchar_id >= 0)
453 scan += cmpchar_table[cmpchar_id]->len,
454 col += cmpchar_table[cmpchar_id]->width;
456 else
457 { /* invalid composite character */
458 scan++;
459 col += 4;
462 else
464 /* Here, we check that the following bytes are valid
465 constituents of multi-byte form. */
466 int len = BYTES_BY_CHAR_HEAD (c), i;
468 for (i = 1, scan++; i < len; i++, scan++)
469 /* We don't need range checking for PTR because there
470 are anchors (`\0') at GAP and Z. */
471 if (CHAR_HEAD_P (POS_ADDR (scan))) break;
472 if (i < len)
473 col += 4, scan -= i - 1;
474 else
475 col += WIDTH_BY_CHAR_HEAD (c);
478 else if (ctl_arrow && (c < 040 || c == 0177))
479 col += 2;
480 else if (c < 040 || c >= 0177)
481 col += 4;
482 else
483 col++;
485 endloop:
487 last_known_column = col;
488 last_known_column_point = PT;
489 last_known_column_modified = MODIFF;
491 return col;
494 /* Return the width in columns of the part of STRING from BEG to END.
495 If BEG is nil, that stands for the beginning of STRING.
496 If END is nil, that stands for the end of STRING. */
498 static int
499 string_display_width (string, beg, end)
500 Lisp_Object string, beg, end;
502 register int col;
503 register unsigned char *ptr, *stop;
504 register int tab_seen;
505 int post_tab;
506 register int c;
507 register int tab_width = XINT (current_buffer->tab_width);
508 int ctl_arrow = !NILP (current_buffer->ctl_arrow);
509 register struct Lisp_Char_Table *dp = buffer_display_table ();
510 int b, e;
512 if (NILP (end))
513 e = XSTRING (string)->size;
514 else
516 CHECK_NUMBER (end, 0);
517 e = XINT (end);
520 if (NILP (beg))
521 b = 0;
522 else
524 CHECK_NUMBER (beg, 0);
525 b = XINT (beg);
528 /* Make a pointer for decrementing through the chars before point. */
529 ptr = XSTRING (string)->data + e;
530 /* Make a pointer to where consecutive chars leave off,
531 going backwards from point. */
532 stop = XSTRING (string)->data + b;
534 if (tab_width <= 0 || tab_width > 1000) tab_width = 8;
536 col = 0, tab_seen = 0, post_tab = 0;
538 while (1)
540 if (ptr == stop)
541 break;
543 c = *--ptr;
544 if (dp != 0 && VECTORP (DISP_CHAR_VECTOR (dp, c)))
545 col += XVECTOR (DISP_CHAR_VECTOR (dp, c))->size;
546 else if (c >= 040 && c < 0177)
547 col++;
548 else if (c == '\n')
549 break;
550 else if (c == '\t')
552 if (tab_seen)
553 col = ((col + tab_width) / tab_width) * tab_width;
555 post_tab += col;
556 col = 0;
557 tab_seen = 1;
559 else
560 col += (ctl_arrow && c < 0200) ? 2 : 4;
563 if (tab_seen)
565 col = ((col + tab_width) / tab_width) * tab_width;
566 col += post_tab;
569 return col;
572 DEFUN ("indent-to", Findent_to, Sindent_to, 1, 2, "NIndent to column: ",
573 "Indent from point with tabs and spaces until COLUMN is reached.\n\
574 Optional second argument MININUM says always do at least MININUM spaces\n\
575 even if that goes past COLUMN; by default, MININUM is zero.")
576 (column, minimum)
577 Lisp_Object column, minimum;
579 int mincol;
580 register int fromcol;
581 register int tab_width = XINT (current_buffer->tab_width);
583 CHECK_NUMBER (column, 0);
584 if (NILP (minimum))
585 XSETFASTINT (minimum, 0);
586 CHECK_NUMBER (minimum, 1);
588 fromcol = current_column ();
589 mincol = fromcol + XINT (minimum);
590 if (mincol < XINT (column)) mincol = XINT (column);
592 if (fromcol == mincol)
593 return make_number (mincol);
595 if (tab_width <= 0 || tab_width > 1000) tab_width = 8;
597 if (indent_tabs_mode)
599 Lisp_Object n;
600 XSETFASTINT (n, mincol / tab_width - fromcol / tab_width);
601 if (XFASTINT (n) != 0)
603 Finsert_char (make_number ('\t'), n, Qt);
605 fromcol = (mincol / tab_width) * tab_width;
609 XSETFASTINT (column, mincol - fromcol);
610 Finsert_char (make_number (' '), column, Qt);
612 last_known_column = mincol;
613 last_known_column_point = PT;
614 last_known_column_modified = MODIFF;
616 XSETINT (column, mincol);
617 return column;
621 DEFUN ("current-indentation", Fcurrent_indentation, Scurrent_indentation,
622 0, 0, 0,
623 "Return the indentation of the current line.\n\
624 This is the horizontal position of the character\n\
625 following any initial whitespace.")
628 Lisp_Object val;
630 XSETFASTINT (val, position_indentation (find_next_newline (PT, -1)));
631 return val;
634 position_indentation (pos)
635 register int pos;
637 register int column = 0;
638 register int tab_width = XINT (current_buffer->tab_width);
639 register unsigned char *p;
640 register unsigned char *stop;
641 unsigned char *start;
642 int next_boundary = pos;
643 int ceiling = pos;
645 if (tab_width <= 0 || tab_width > 1000) tab_width = 8;
647 p = POS_ADDR (pos);
648 /* STOP records the value of P at which we will need
649 to think about the gap, or about invisible text,
650 or about the end of the buffer. */
651 stop = p;
652 /* START records the starting value of P. */
653 start = p;
654 while (1)
656 while (p == stop)
658 int stop_pos;
660 /* If we have updated P, set POS to match.
661 The first time we enter the loop, POS is already right. */
662 if (p != start)
663 pos = PTR_CHAR_POS (p);
664 /* Consider the various reasons STOP might have been set here. */
665 if (pos == ZV)
666 return column;
667 if (pos == next_boundary)
668 pos = skip_invisible (pos, &next_boundary, ZV, Qnil);
669 if (pos >= ceiling)
670 ceiling = BUFFER_CEILING_OF (pos) + 1;
671 /* Compute the next place we need to stop and think,
672 and set STOP accordingly. */
673 stop_pos = min (ceiling, next_boundary);
674 /* The -1 and +1 arrange to point at the first byte of gap
675 (if STOP_POS is the position of the gap)
676 rather than at the data after the gap. */
678 stop = POS_ADDR (stop_pos - 1) + 1;
679 p = POS_ADDR (pos);
681 switch (*p++)
683 case ' ':
684 column++;
685 break;
686 case '\t':
687 column += tab_width - column % tab_width;
688 break;
689 default:
690 return column;
695 /* Test whether the line beginning at POS is indented beyond COLUMN.
696 Blank lines are treated as if they had the same indentation as the
697 preceding line. */
699 indented_beyond_p (pos, column)
700 int pos, column;
702 while (pos > BEGV && FETCH_BYTE (pos) == '\n')
703 pos = find_next_newline_no_quit (pos - 1, -1);
704 return (position_indentation (pos) >= column);
707 DEFUN ("move-to-column", Fmove_to_column, Smove_to_column, 1, 2, "p",
708 "Move point to column COLUMN in the current line.\n\
709 The column of a character is calculated by adding together the widths\n\
710 as displayed of the previous characters in the line.\n\
711 This function ignores line-continuation;\n\
712 there is no upper limit on the column number a character can have\n\
713 and horizontal scrolling has no effect.\n\
715 If specified column is within a character, point goes after that character.\n\
716 If it's past end of line, point goes to end of line.\n\n\
717 A non-nil second (optional) argument FORCE means, if the line\n\
718 is too short to reach column COLUMN then add spaces/tabs to get there,\n\
719 and if COLUMN is in the middle of a tab character, change it to spaces.\n\
721 The return value is the current column.")
722 (column, force)
723 Lisp_Object column, force;
725 register int pos;
726 register int col = current_column ();
727 register int goal;
728 register int end;
729 register int tab_width = XINT (current_buffer->tab_width);
730 register int ctl_arrow = !NILP (current_buffer->ctl_arrow);
731 register struct Lisp_Char_Table *dp = buffer_display_table ();
732 register int multibyte = !NILP (current_buffer->enable_multibyte_characters);
734 Lisp_Object val;
735 int prev_col;
736 int c;
738 int next_boundary;
740 if (tab_width <= 0 || tab_width > 1000) tab_width = 8;
741 CHECK_NATNUM (column, 0);
742 goal = XINT (column);
744 pos = PT;
745 end = ZV;
746 next_boundary = pos;
748 /* If we're starting past the desired column,
749 back up to beginning of line and scan from there. */
750 if (col > goal)
752 end = pos;
753 pos = current_column_bol_cache;
754 col = 0;
757 while (pos < end)
759 while (pos == next_boundary)
761 pos = skip_invisible (pos, &next_boundary, end, Qnil);
762 if (pos >= end)
763 goto endloop;
766 /* Test reaching the goal column. We do this after skipping
767 invisible characters, so that we put point before the
768 character on which the cursor will appear. */
769 if (col >= goal)
770 break;
772 c = FETCH_BYTE (pos);
773 if (dp != 0 && VECTORP (DISP_CHAR_VECTOR (dp, c)))
775 col += XVECTOR (DISP_CHAR_VECTOR (dp, c))->size;
776 pos++;
777 continue;
779 if (c == '\n')
780 break;
781 if (c == '\r' && EQ (current_buffer->selective_display, Qt))
782 break;
783 pos++;
784 if (c == '\t')
786 prev_col = col;
787 col += tab_width;
788 col = col / tab_width * tab_width;
790 else if (ctl_arrow && (c < 040 || c == 0177))
791 col += 2;
792 else if (c < 040 || c == 0177)
793 col += 4;
794 else if (c < 0177)
795 col++;
796 else if (multibyte && BASE_LEADING_CODE_P (c))
798 /* Start of multi-byte form. */
799 unsigned char *ptr;
801 pos--; /* rewind to the character head */
802 ptr = POS_ADDR (pos);
803 if (c == LEADING_CODE_COMPOSITION)
805 int cmpchar_id = str_cmpchar_id (ptr, end - pos);
807 if (cmpchar_id >= 0)
809 col += cmpchar_table[cmpchar_id]->width;
810 pos += cmpchar_table[cmpchar_id]->len;
812 else
813 { /* invalid composite character */
814 col += 4;
815 pos++;
818 else
820 /* Here, we check that the following bytes are valid
821 constituents of multi-byte form. */
822 int len = BYTES_BY_CHAR_HEAD (c), i;
824 for (i = 1, ptr++; i < len; i++, ptr++)
825 /* We don't need range checking for PTR because there
826 are anchors (`\0') both at GPT and Z. */
827 if (CHAR_HEAD_P (ptr)) break;
828 if (i < len)
829 col += 4, pos++;
830 else
831 col += WIDTH_BY_CHAR_HEAD (c), pos += i;
834 else
835 col += 4;
837 endloop:
839 SET_PT (pos);
841 /* If a tab char made us overshoot, change it to spaces
842 and scan through it again. */
843 if (!NILP (force) && col > goal && c == '\t' && prev_col < goal)
845 int old_point;
847 del_range (PT - 1, PT);
848 Findent_to (make_number (goal), Qnil);
849 old_point = PT;
850 Findent_to (make_number (col), Qnil);
851 SET_PT (old_point);
852 /* Set the last_known... vars consistently. */
853 col = goal;
856 /* If line ends prematurely, add space to the end. */
857 if (col < goal && !NILP (force))
858 Findent_to (make_number (col = goal), Qnil);
860 last_known_column = col;
861 last_known_column_point = PT;
862 last_known_column_modified = MODIFF;
864 XSETFASTINT (val, col);
865 return val;
868 /* compute_motion: compute buffer posn given screen posn and vice versa */
870 struct position val_compute_motion;
872 /* Scan the current buffer forward from offset FROM, pretending that
873 this is at line FROMVPOS, column FROMHPOS, until reaching buffer
874 offset TO or line TOVPOS, column TOHPOS (whichever comes first),
875 and return the ending buffer position and screen location. If we
876 can't hit the requested column exactly (because of a tab or other
877 multi-column character), overshoot.
879 DID_MOTION is 1 if FROMHPOS has already accounted for overlay strings
880 at FROM. This is the case if FROMVPOS and FROMVPOS came from an
881 earlier call to compute_motion. The other common case is that FROMHPOS
882 is zero and FROM is a position that "belongs" at column zero, but might
883 be shifted by overlay strings; in this case DID_MOTION should be 0.
885 WIDTH is the number of columns available to display text;
886 compute_motion uses this to handle continuation lines and such.
887 HSCROLL is the number of columns not being displayed at the left
888 margin; this is usually taken from a window's hscroll member.
889 TAB_OFFSET is the number of columns of the first tab that aren't
890 being displayed, perhaps because of a continuation line or
891 something.
893 compute_motion returns a pointer to a struct position. The bufpos
894 member gives the buffer position at the end of the scan, and hpos
895 and vpos give its cartesian location. prevhpos is the column at
896 which the character before bufpos started, and contin is non-zero
897 if we reached the current line by continuing the previous.
899 Note that FROMHPOS and TOHPOS should be expressed in real screen
900 columns, taking HSCROLL and the truncation glyph at the left margin
901 into account. That is, beginning-of-line moves you to the hpos
902 -HSCROLL + (HSCROLL > 0).
904 For example, to find the buffer position of column COL of line LINE
905 of a certain window, pass the window's starting location as FROM
906 and the window's upper-left coordinates as FROMVPOS and FROMHPOS.
907 Pass the buffer's ZV as TO, to limit the scan to the end of the
908 visible section of the buffer, and pass LINE and COL as TOVPOS and
909 TOHPOS.
911 When displaying in window w, a typical formula for WIDTH is:
913 window_width - 1
914 - (has_vertical_scroll_bars
915 ? FRAME_SCROLL_BAR_COLS (XFRAME (window->frame))
916 : (window_width + window_left != frame_width))
918 where
919 window_width is XFASTINT (w->width),
920 window_left is XFASTINT (w->left),
921 has_vertical_scroll_bars is
922 FRAME_HAS_VERTICAL_SCROLL_BARS (XFRAME (WINDOW_FRAME (window)))
923 and frame_width = FRAME_WIDTH (XFRAME (window->frame))
925 Or you can let window_internal_width do this all for you, and write:
926 window_internal_width (w) - 1
928 The `-1' accounts for the continuation-line backslashes; the rest
929 accounts for window borders if the window is split horizontally, and
930 the scroll bars if they are turned on. */
932 struct position *
933 compute_motion (from, fromvpos, fromhpos, did_motion, to, tovpos, tohpos, width, hscroll, tab_offset, win)
934 int from, fromvpos, fromhpos, to, tovpos, tohpos;
935 int did_motion;
936 register int width;
937 int hscroll, tab_offset;
938 struct window *win;
940 register int hpos = fromhpos;
941 register int vpos = fromvpos;
943 register int pos;
944 register int c;
945 register int tab_width = XFASTINT (current_buffer->tab_width);
946 register int ctl_arrow = !NILP (current_buffer->ctl_arrow);
947 register struct Lisp_Char_Table *dp = window_display_table (win);
948 int selective
949 = (INTEGERP (current_buffer->selective_display)
950 ? XINT (current_buffer->selective_display)
951 : !NILP (current_buffer->selective_display) ? -1 : 0);
952 int prev_hpos = 0;
953 int selective_rlen
954 = (selective && dp && VECTORP (DISP_INVIS_VECTOR (dp))
955 ? XVECTOR (DISP_INVIS_VECTOR (dp))->size : 0);
956 /* The next location where the `invisible' property changes, or an
957 overlay starts or ends. */
958 int next_boundary = from;
960 /* For computing runs of characters with similar widths.
961 Invariant: width_run_width is zero, or all the characters
962 from width_run_start to width_run_end have a fixed width of
963 width_run_width. */
964 int width_run_start = from;
965 int width_run_end = from;
966 int width_run_width = 0;
967 Lisp_Object *width_table;
968 Lisp_Object buffer;
970 /* The next buffer pos where we should consult the width run cache. */
971 int next_width_run = from;
972 Lisp_Object window;
974 int multibyte = !NILP (current_buffer->enable_multibyte_characters);
975 int wide_column = 0; /* Set to 1 when a previous character
976 is wide-colomn. */
977 int prev_pos; /* Previous buffer position. */
978 int contin_hpos; /* HPOS of last column of continued line. */
979 int prev_tab_offset; /* Previous tab offset. */
981 XSETBUFFER (buffer, current_buffer);
982 XSETWINDOW (window, win);
984 width_run_cache_on_off ();
985 if (dp == buffer_display_table ())
986 width_table = (VECTORP (current_buffer->width_table)
987 ? XVECTOR (current_buffer->width_table)->contents
988 : 0);
989 else
990 /* If the window has its own display table, we can't use the width
991 run cache, because that's based on the buffer's display table. */
992 width_table = 0;
994 if (tab_width <= 0 || tab_width > 1000) tab_width = 8;
996 pos = prev_pos = from;
997 contin_hpos = 0;
998 prev_tab_offset = tab_offset;
999 while (1)
1001 while (pos == next_boundary)
1003 int newpos;
1005 /* If the caller says that the screen position came from an earlier
1006 call to compute_motion, then we've already accounted for the
1007 overlay strings at point. This is only true the first time
1008 through, so clear the flag after testing it. */
1009 if (!did_motion)
1010 /* We need to skip past the overlay strings. Currently those
1011 strings must not contain TAB;
1012 if we want to relax that restriction, something will have
1013 to be changed here. */
1015 unsigned char *ovstr;
1016 int ovlen = overlay_strings (pos, win, &ovstr);
1017 hpos += (multibyte ? strwidth (ovstr, ovlen) : ovlen);
1019 did_motion = 0;
1021 if (pos >= to)
1022 break;
1024 /* Advance POS past invisible characters
1025 (but not necessarily all that there are here),
1026 and store in next_boundary the next position where
1027 we need to call skip_invisible. */
1028 newpos = skip_invisible (pos, &next_boundary, to, window);
1030 if (newpos >= to)
1031 goto after_loop;
1033 pos = newpos;
1036 /* Handle right margin. */
1037 /* Note on a wide-column character.
1039 Characters are classified into the following three categories
1040 according to the width (columns occupied on screen).
1042 (1) single-column character: ex. `a'
1043 (2) multi-column character: ex. `^A', TAB, `\033'
1044 (3) wide-column character: ex. Japanese character, Chinese character
1045 (In the following example, `W_' stands for them.)
1047 Multi-column characters can be divided around the right margin,
1048 but wide-column characters cannot.
1050 NOTE:
1052 (*) The cursor is placed on the next character after the point.
1054 ----------
1055 abcdefghi\
1056 j ^---- next after the point
1057 ^--- next char. after the point.
1058 ----------
1059 In case of sigle-column character
1061 ----------
1062 abcdefgh\\
1063 033 ^---- next after the point, next char. after the point.
1064 ----------
1065 In case of multi-column character
1067 ----------
1068 abcdefgh\\
1069 W_ ^---- next after the point
1070 ^---- next char. after the point.
1071 ----------
1072 In case of wide-column character
1074 The problem here is continuation at a wide-column character.
1075 In this case, the line may shorter less than WIDTH.
1076 And we find the continuation AFTER it occurs.
1080 if (hpos > width)
1082 if (hscroll
1083 || (truncate_partial_width_windows
1084 && width + 1 < FRAME_WIDTH (XFRAME (WINDOW_FRAME (win))))
1085 || !NILP (current_buffer->truncate_lines))
1087 /* Truncating: skip to newline. */
1088 if (pos <= to) /* This IF is needed because we may past TO */
1089 pos = find_before_next_newline (pos, to, 1);
1090 hpos = width;
1091 /* If we just skipped next_boundary,
1092 loop around in the main while
1093 and handle it. */
1094 if (pos >= next_boundary)
1095 next_boundary = pos + 1;
1096 prev_hpos = width;
1097 prev_tab_offset = tab_offset;
1099 else
1101 /* Continuing. */
1102 /* Remember the previous value. */
1103 prev_tab_offset = tab_offset;
1105 if (wide_column)
1107 hpos -= prev_hpos;
1108 tab_offset += prev_hpos;
1110 else
1112 tab_offset += width;
1113 hpos -= width;
1115 vpos++;
1116 contin_hpos = prev_hpos;
1117 prev_hpos = 0;
1121 /* Stop if past the target buffer position or screen position. */
1122 if (pos > to)
1124 /* Go back to the previous position. */
1125 pos = prev_pos;
1126 hpos = prev_hpos;
1127 tab_offset = prev_tab_offset;
1129 /* NOTE on contin_hpos, hpos, and prev_hpos.
1131 ----------
1132 abcdefgh\\
1133 W_ ^---- contin_hpos
1134 | ^----- hpos
1135 \---- prev_hpos
1136 ----------
1139 if (contin_hpos && prev_hpos == 0
1140 && contin_hpos < width && !wide_column)
1142 /* Line breaking occurs in the middle of multi-column
1143 character. Go back to previous line. */
1144 hpos = contin_hpos;
1145 vpos = vpos - 1;
1147 else if (c == '\n')
1148 /* If previous character is NEWLINE,
1149 set VPOS back to previous line */
1150 vpos = vpos - 1;
1151 break;
1154 if (vpos > tovpos || vpos == tovpos && hpos >= tohpos)
1156 if (contin_hpos && prev_hpos == 0
1157 && ((hpos > tohpos && contin_hpos == width) || wide_column))
1158 { /* Line breaks because we can't put the character at the
1159 previous line any more. It is not the multi-column
1160 character continued in middle. Go back to previous
1161 buffer position, screen position, and set tab offset
1162 to previous value. It's the beginning of the
1163 line. */
1164 pos = prev_pos;
1165 hpos = prev_hpos;
1166 tab_offset = prev_tab_offset;
1168 break;
1170 if (pos == ZV) /* We cannot go beyond ZV. Stop here. */
1171 break;
1173 prev_hpos = hpos;
1174 prev_pos = pos;
1175 wide_column = 0;
1177 /* Consult the width run cache to see if we can avoid inspecting
1178 the text character-by-character. */
1179 if (current_buffer->width_run_cache && pos >= next_width_run)
1181 int run_end;
1182 int common_width
1183 = region_cache_forward (current_buffer,
1184 current_buffer->width_run_cache,
1185 pos, &run_end);
1187 /* A width of zero means the character's width varies (like
1188 a tab), is meaningless (like a newline), or we just don't
1189 want to skip over it for some other reason. */
1190 if (common_width != 0)
1192 int run_end_hpos;
1194 /* Don't go past the final buffer posn the user
1195 requested. */
1196 if (run_end > to)
1197 run_end = to;
1199 run_end_hpos = hpos + (run_end - pos) * common_width;
1201 /* Don't go past the final horizontal position the user
1202 requested. */
1203 if (vpos == tovpos && run_end_hpos > tohpos)
1205 run_end = pos + (tohpos - hpos) / common_width;
1206 run_end_hpos = hpos + (run_end - pos) * common_width;
1209 /* Don't go past the margin. */
1210 if (run_end_hpos >= width)
1212 run_end = pos + (width - hpos) / common_width;
1213 run_end_hpos = hpos + (run_end - pos) * common_width;
1216 hpos = run_end_hpos;
1217 if (run_end > pos)
1218 prev_hpos = hpos - common_width;
1219 pos = run_end;
1222 next_width_run = run_end + 1;
1225 /* We have to scan the text character-by-character. */
1226 else
1228 c = FETCH_BYTE (pos);
1229 pos++;
1231 /* Perhaps add some info to the width_run_cache. */
1232 if (current_buffer->width_run_cache)
1234 /* Is this character part of the current run? If so, extend
1235 the run. */
1236 if (pos - 1 == width_run_end
1237 && XFASTINT (width_table[c]) == width_run_width)
1238 width_run_end = pos;
1240 /* The previous run is over, since this is a character at a
1241 different position, or a different width. */
1242 else
1244 /* Have we accumulated a run to put in the cache?
1245 (Currently, we only cache runs of width == 1). */
1246 if (width_run_start < width_run_end
1247 && width_run_width == 1)
1248 know_region_cache (current_buffer,
1249 current_buffer->width_run_cache,
1250 width_run_start, width_run_end);
1252 /* Start recording a new width run. */
1253 width_run_width = XFASTINT (width_table[c]);
1254 width_run_start = pos - 1;
1255 width_run_end = pos;
1259 if (dp != 0 && VECTORP (DISP_CHAR_VECTOR (dp, c)))
1260 hpos += XVECTOR (DISP_CHAR_VECTOR (dp, c))->size;
1261 else if (c >= 040 && c < 0177)
1262 hpos++;
1263 else if (c == '\t')
1265 int tem = (hpos + tab_offset + hscroll - (hscroll > 0)) % tab_width;
1266 if (tem < 0)
1267 tem += tab_width;
1268 hpos += tab_width - tem;
1270 else if (c == '\n')
1272 if (selective > 0 && indented_beyond_p (pos, selective))
1274 /* If (pos == to), we don't have to take care of
1275 selective display. */
1276 if (pos < to)
1278 /* Skip any number of invisible lines all at once */
1280 pos = find_before_next_newline (pos, to, 1) + 1;
1281 while (pos < to
1282 && indented_beyond_p (pos, selective));
1283 /* Allow for the " ..." that is displayed for them. */
1284 if (selective_rlen)
1286 hpos += selective_rlen;
1287 if (hpos >= width)
1288 hpos = width;
1290 --pos;
1291 /* We have skipped the invis text, but not the
1292 newline after. */
1295 else
1297 /* A visible line. */
1298 vpos++;
1299 hpos = 0;
1300 hpos -= hscroll;
1301 /* Count the truncation glyph on column 0 */
1302 if (hscroll > 0)
1303 hpos++;
1304 tab_offset = 0;
1306 contin_hpos = 0;
1308 else if (c == CR && selective < 0)
1310 /* In selective display mode,
1311 everything from a ^M to the end of the line is invisible.
1312 Stop *before* the real newline. */
1313 if (pos < to)
1314 pos = find_before_next_newline (pos, to, 1);
1315 /* If we just skipped next_boundary,
1316 loop around in the main while
1317 and handle it. */
1318 if (pos > next_boundary)
1319 next_boundary = pos;
1320 /* Allow for the " ..." that is displayed for them. */
1321 if (selective_rlen)
1323 hpos += selective_rlen;
1324 if (hpos >= width)
1325 hpos = width;
1328 else if (multibyte && BASE_LEADING_CODE_P (c))
1330 /* Start of multi-byte form. */
1331 unsigned char *ptr;
1332 int len, actual_len;
1334 pos--; /* rewind POS */
1336 ptr = (((pos) >= GPT ? GAP_SIZE : 0) + (pos) + BEG_ADDR - 1);
1337 len = ((pos) >= GPT ? ZV : GPT) - (pos);
1339 c = STRING_CHAR_AND_LENGTH (ptr, len, actual_len);
1341 if (dp != 0 && VECTORP (DISP_CHAR_VECTOR (dp, c)))
1342 hpos += XVECTOR (DISP_CHAR_VECTOR (dp, c))->size;
1343 else if (actual_len == 1)
1344 hpos += 4;
1345 else if (COMPOSITE_CHAR_P (c))
1347 int id = COMPOSITE_CHAR_ID (c);
1348 int width = (id < n_cmpchars) ? cmpchar_table[id]->width : 0;
1349 hpos += width;
1350 if (width > 1)
1351 wide_column = 1;
1353 else
1355 int width = WIDTH_BY_CHAR_HEAD (*ptr);
1356 hpos += width;
1357 if (width > 1)
1358 wide_column = 1;
1361 pos += actual_len;
1363 else
1364 hpos += (ctl_arrow && c < 0200) ? 2 : 4;
1368 after_loop:
1370 /* Remember any final width run in the cache. */
1371 if (current_buffer->width_run_cache
1372 && width_run_width == 1
1373 && width_run_start < width_run_end)
1374 know_region_cache (current_buffer, current_buffer->width_run_cache,
1375 width_run_start, width_run_end);
1377 val_compute_motion.bufpos = pos;
1378 val_compute_motion.hpos = hpos;
1379 val_compute_motion.vpos = vpos;
1380 val_compute_motion.prevhpos = prev_hpos;
1381 /* We alalways handle all of them here; none of them remain to do. */
1382 val_compute_motion.ovstring_chars_done = 0;
1384 /* Nonzero if have just continued a line */
1385 val_compute_motion.contin = (contin_hpos && prev_hpos == 0);
1387 return &val_compute_motion;
1390 #if 0 /* The doc string is too long for some compilers,
1391 but make-docfile can find it in this comment. */
1392 DEFUN ("compute-motion", Ffoo, Sfoo, 7, 7, 0,
1393 "Scan through the current buffer, calculating screen position.\n\
1394 Scan the current buffer forward from offset FROM,\n\
1395 assuming it is at position FROMPOS--a cons of the form (HPOS . VPOS)--\n\
1396 to position TO or position TOPOS--another cons of the form (HPOS . VPOS)--\n\
1397 and return the ending buffer position and screen location.\n\
1399 There are three additional arguments:\n\
1401 WIDTH is the number of columns available to display text;\n\
1402 this affects handling of continuation lines.\n\
1403 This is usually the value returned by `window-width', less one (to allow\n\
1404 for the continuation glyph).\n\
1406 OFFSETS is either nil or a cons cell (HSCROLL . TAB-OFFSET).\n\
1407 HSCROLL is the number of columns not being displayed at the left\n\
1408 margin; this is usually taken from a window's hscroll member.\n\
1409 TAB-OFFSET is the number of columns of the first tab that aren't\n\
1410 being displayed, perhaps because the line was continued within it.\n\
1411 If OFFSETS is nil, HSCROLL and TAB-OFFSET are assumed to be zero.\n\
1413 WINDOW is the window to operate on. It is used to choose the display table;\n\
1414 if it is showing the current buffer, it is used also for\n\
1415 deciding which overlay properties apply.\n\
1416 Note that `compute-motion' always operates on the current buffer.\n\
1418 The value is a list of five elements:\n\
1419 (POS HPOS VPOS PREVHPOS CONTIN)\n\
1420 POS is the buffer position where the scan stopped.\n\
1421 VPOS is the vertical position where the scan stopped.\n\
1422 HPOS is the horizontal position where the scan stopped.\n\
1424 PREVHPOS is the horizontal position one character back from POS.\n\
1425 CONTIN is t if a line was continued after (or within) the previous character.\n\
1427 For example, to find the buffer position of column COL of line LINE\n\
1428 of a certain window, pass the window's starting location as FROM\n\
1429 and the window's upper-left coordinates as FROMPOS.\n\
1430 Pass the buffer's (point-max) as TO, to limit the scan to the end of the\n\
1431 visible section of the buffer, and pass LINE and COL as TOPOS.")
1432 (from, frompos, to, topos, width, offsets, window)
1433 #endif
1435 DEFUN ("compute-motion", Fcompute_motion, Scompute_motion, 7, 7, 0,
1437 (from, frompos, to, topos, width, offsets, window)
1438 Lisp_Object from, frompos, to, topos;
1439 Lisp_Object width, offsets, window;
1441 Lisp_Object bufpos, hpos, vpos, prevhpos, contin;
1442 struct position *pos;
1443 int hscroll, tab_offset;
1445 CHECK_NUMBER_COERCE_MARKER (from, 0);
1446 CHECK_CONS (frompos, 0);
1447 CHECK_NUMBER (XCONS (frompos)->car, 0);
1448 CHECK_NUMBER (XCONS (frompos)->cdr, 0);
1449 CHECK_NUMBER_COERCE_MARKER (to, 0);
1450 CHECK_CONS (topos, 0);
1451 CHECK_NUMBER (XCONS (topos)->car, 0);
1452 CHECK_NUMBER (XCONS (topos)->cdr, 0);
1453 CHECK_NUMBER (width, 0);
1454 if (!NILP (offsets))
1456 CHECK_CONS (offsets, 0);
1457 CHECK_NUMBER (XCONS (offsets)->car, 0);
1458 CHECK_NUMBER (XCONS (offsets)->cdr, 0);
1459 hscroll = XINT (XCONS (offsets)->car);
1460 tab_offset = XINT (XCONS (offsets)->cdr);
1462 else
1463 hscroll = tab_offset = 0;
1465 if (NILP (window))
1466 window = Fselected_window ();
1467 else
1468 CHECK_LIVE_WINDOW (window, 0);
1470 pos = compute_motion (XINT (from), XINT (XCONS (frompos)->cdr),
1471 XINT (XCONS (frompos)->car), 0,
1472 XINT (to), XINT (XCONS (topos)->cdr),
1473 XINT (XCONS (topos)->car),
1474 XINT (width), hscroll, tab_offset,
1475 XWINDOW (window));
1477 XSETFASTINT (bufpos, pos->bufpos);
1478 XSETINT (hpos, pos->hpos);
1479 XSETINT (vpos, pos->vpos);
1480 XSETINT (prevhpos, pos->prevhpos);
1482 return Fcons (bufpos,
1483 Fcons (hpos,
1484 Fcons (vpos,
1485 Fcons (prevhpos,
1486 Fcons (pos->contin ? Qt : Qnil, Qnil)))));
1490 /* Return the column of position POS in window W's buffer.
1491 The result is rounded down to a multiple of the internal width of W.
1492 This is the amount of indentation of position POS
1493 that is not visible in its horizontal position in the window. */
1496 pos_tab_offset (w, pos)
1497 struct window *w;
1498 register int pos;
1500 int opoint = PT;
1501 int col;
1502 int width = window_internal_width (w) - 1;
1504 if (pos == BEGV)
1505 return MINI_WINDOW_P (w) ? -minibuf_prompt_width : 0;
1506 if (FETCH_BYTE (pos - 1) == '\n')
1507 return 0;
1508 TEMP_SET_PT (pos);
1509 col = current_column ();
1510 TEMP_SET_PT (opoint);
1511 /* Modulo is no longer valid, as a line may get shorter than WIDTH
1512 columns by continuation of a wide-column character. Just return
1513 COL here. */
1514 #if 0
1515 /* In the continuation of the first line in a minibuffer we must
1516 take the width of the prompt into account. */
1517 if (MINI_WINDOW_P (w) && col >= width - minibuf_prompt_width
1518 && find_next_newline_no_quit (pos, -1) == BEGV)
1519 return col - (col + minibuf_prompt_width) % width;
1520 return col - (col % width);
1521 #endif
1522 return col;
1526 /* Fvertical_motion and vmotion */
1527 struct position val_vmotion;
1529 struct position *
1530 vmotion (from, vtarget, w)
1531 register int from, vtarget;
1532 struct window *w;
1534 int width = window_internal_width (w) - 1;
1535 int hscroll = XINT (w->hscroll);
1536 struct position pos;
1537 /* vpos is cumulative vertical position, changed as from is changed */
1538 register int vpos = 0;
1539 Lisp_Object prevline;
1540 register int first;
1541 int lmargin = hscroll > 0 ? 1 - hscroll : 0;
1542 int selective
1543 = (INTEGERP (current_buffer->selective_display)
1544 ? XINT (current_buffer->selective_display)
1545 : !NILP (current_buffer->selective_display) ? -1 : 0);
1546 Lisp_Object window;
1547 int start_hpos = 0;
1548 int did_motion;
1550 XSETWINDOW (window, w);
1552 /* The omission of the clause
1553 && marker_position (w->start) == BEG
1554 here is deliberate; I think we want to measure from the prompt
1555 position even if the minibuffer window has scrolled. */
1556 if (EQ (window, minibuf_window))
1558 if (minibuf_prompt_width == 0 && STRINGP (minibuf_prompt))
1559 minibuf_prompt_width
1560 = string_display_width (minibuf_prompt, Qnil, Qnil);
1562 start_hpos = minibuf_prompt_width;
1565 if (vpos >= vtarget)
1567 /* To move upward, go a line at a time until
1568 we have gone at least far enough */
1570 first = 1;
1572 while ((vpos > vtarget || first) && from > BEGV)
1574 Lisp_Object propval;
1576 XSETFASTINT (prevline, find_next_newline_no_quit (from - 1, -1));
1577 while (XFASTINT (prevline) > BEGV
1578 && ((selective > 0
1579 && indented_beyond_p (XFASTINT (prevline), selective))
1580 #ifdef USE_TEXT_PROPERTIES
1581 /* watch out for newlines with `invisible' property */
1582 || (propval = Fget_char_property (prevline,
1583 Qinvisible,
1584 window),
1585 TEXT_PROP_MEANS_INVISIBLE (propval))
1586 #endif
1588 XSETFASTINT (prevline,
1589 find_next_newline_no_quit (XFASTINT (prevline) - 1,
1590 -1));
1591 pos = *compute_motion (XFASTINT (prevline), 0,
1592 lmargin + (XFASTINT (prevline) == BEG
1593 ? start_hpos : 0),
1595 from,
1596 /* Don't care for VPOS... */
1597 1 << (BITS_PER_SHORT - 1),
1598 /* ... nor HPOS. */
1599 1 << (BITS_PER_SHORT - 1),
1600 width, hscroll,
1601 /* This compensates for start_hpos
1602 so that a tab as first character
1603 still occupies 8 columns. */
1604 (XFASTINT (prevline) == BEG
1605 ? -start_hpos : 0),
1607 vpos -= pos.vpos;
1608 first = 0;
1609 from = XFASTINT (prevline);
1612 /* If we made exactly the desired vertical distance,
1613 or if we hit beginning of buffer,
1614 return point found */
1615 if (vpos >= vtarget)
1617 val_vmotion.bufpos = from;
1618 val_vmotion.vpos = vpos;
1619 val_vmotion.hpos = lmargin;
1620 val_vmotion.contin = 0;
1621 val_vmotion.prevhpos = 0;
1622 val_vmotion.ovstring_chars_done = 0;
1623 val_vmotion.tab_offset = 0; /* For accumulating tab offset. */
1624 return &val_vmotion;
1627 /* Otherwise find the correct spot by moving down */
1629 /* Moving downward is simple, but must calculate from beg of line
1630 to determine hpos of starting point */
1631 if (from > BEGV && FETCH_BYTE (from - 1) != '\n')
1633 Lisp_Object propval;
1635 XSETFASTINT (prevline, find_next_newline_no_quit (from, -1));
1636 while (XFASTINT (prevline) > BEGV
1637 && ((selective > 0
1638 && indented_beyond_p (XFASTINT (prevline), selective))
1639 #ifdef USE_TEXT_PROPERTIES
1640 /* watch out for newlines with `invisible' property */
1641 || (propval = Fget_char_property (prevline, Qinvisible,
1642 window),
1643 TEXT_PROP_MEANS_INVISIBLE (propval))
1644 #endif
1646 XSETFASTINT (prevline,
1647 find_next_newline_no_quit (XFASTINT (prevline) - 1,
1648 -1));
1649 pos = *compute_motion (XFASTINT (prevline), 0,
1650 lmargin + (XFASTINT (prevline) == BEG
1651 ? start_hpos : 0),
1653 from,
1654 /* Don't care for VPOS... */
1655 1 << (BITS_PER_SHORT - 1),
1656 /* ... nor HPOS. */
1657 1 << (BITS_PER_SHORT - 1),
1658 width, hscroll,
1659 (XFASTINT (prevline) == BEG ? -start_hpos : 0),
1661 did_motion = 1;
1663 else
1665 pos.hpos = lmargin + (from == BEG ? start_hpos : 0);
1666 pos.vpos = 0;
1667 pos.tab_offset = 0;
1668 did_motion = 0;
1670 return compute_motion (from, vpos, pos.hpos, did_motion,
1671 ZV, vtarget, - (1 << (BITS_PER_SHORT - 1)),
1672 width, hscroll,
1673 pos.tab_offset - (from == BEG ? start_hpos : 0),
1677 DEFUN ("vertical-motion", Fvertical_motion, Svertical_motion, 1, 2, 0,
1678 "Move point to start of the screen line LINES lines down.\n\
1679 If LINES is negative, this means moving up.\n\
1681 This function is an ordinary cursor motion function\n\
1682 which calculates the new position based on how text would be displayed.\n\
1683 The new position may be the start of a line,\n\
1684 or just the start of a continuation line.\n\
1685 The function returns number of screen lines moved over;\n\
1686 that usually equals LINES, but may be closer to zero\n\
1687 if beginning or end of buffer was reached.\n\
1689 The optional second argument WINDOW specifies the window to use for\n\
1690 parameters such as width, horizontal scrolling, and so on.\n\
1691 The default is to use the selected window's parameters.\n\
1693 `vertical-motion' always uses the current buffer,\n\
1694 regardless of which buffer is displayed in WINDOW.\n\
1695 This is consistent with other cursor motion functions\n\
1696 and makes it possible to use `vertical-motion' in any buffer,\n\
1697 whether or not it is currently displayed in some window.")
1698 (lines, window)
1699 Lisp_Object lines, window;
1701 struct position pos;
1703 CHECK_NUMBER (lines, 0);
1704 if (! NILP (window))
1705 CHECK_WINDOW (window, 0);
1706 else
1707 window = selected_window;
1709 pos = *vmotion (PT, (int) XINT (lines), XWINDOW (window));
1711 SET_PT (pos.bufpos);
1712 return make_number (pos.vpos);
1715 /* file's initialization. */
1717 syms_of_indent ()
1719 DEFVAR_BOOL ("indent-tabs-mode", &indent_tabs_mode,
1720 "*Indentation can insert tabs if this is non-nil.\n\
1721 Setting this variable automatically makes it local to the current buffer.");
1722 indent_tabs_mode = 1;
1724 defsubr (&Scurrent_indentation);
1725 defsubr (&Sindent_to);
1726 defsubr (&Scurrent_column);
1727 defsubr (&Smove_to_column);
1728 defsubr (&Svertical_motion);
1729 defsubr (&Scompute_motion);