1 /*
2 * Copyright (C) 1984-2019 Mark Nudelman
3 *
4 * You may distribute under the terms of either the GNU General Public
5 * License or the Less License, as specified in the README file.
6 *
7 * For more information, see the README file.
8 */
9
10 /*
11 * Routines to manipulate the "line buffer".
12 * The line buffer holds a line of output as it is being built
13 * in preparation for output to the screen.
14 */
15
16 #include "less.h"
17 #include "charset.h"
18 #include "position.h"
19
20 #if MSDOS_COMPILER==WIN32C
21 #define WIN32_LEAN_AND_MEAN
22 #include <windows.h>
23 #endif
24
25 static char *linebuf = NULL; /* Buffer which holds the current output line */
26 static char *attr = NULL; /* Extension of linebuf to hold attributes */
27 public int size_linebuf = 0; /* Size of line buffer (and attr buffer) */
28
29 static int cshift; /* Current left-shift of output line buffer */
30 public int hshift; /* Desired left-shift of output line buffer */
31 public int tabstops[TABSTOP_MAX] = { 0 }; /* Custom tabstops */
32 public int ntabstops = 1; /* Number of tabstops */
33 public int tabdefault = 8; /* Default repeated tabstops */
34 public POSITION highest_hilite; /* Pos of last hilite in file found so far */
35
36 static int curr; /* Index into linebuf */
37 static int column; /* Printable length, accounting for
38 backspaces, etc. */
39 static int right_curr;
40 static int right_column;
41 static int overstrike; /* Next char should overstrike previous char */
42 static int last_overstrike = AT_NORMAL;
43 static int is_null_line; /* There is no current line */
44 static int lmargin; /* Left margin */
45 static LWCHAR pendc;
46 static POSITION pendpos;
47 static char *end_ansi_chars;
48 static char *mid_ansi_chars;
49
50 static int attr_swidth LESSPARAMS ((int a));
51 static int attr_ewidth LESSPARAMS ((int a));
52 static int do_append LESSPARAMS ((LWCHAR ch, char *rep, POSITION pos));
53
54 extern int sigs;
55 extern int bs_mode;
56 extern int linenums;
57 extern int ctldisp;
58 extern int twiddle;
59 extern int binattr;
60 extern int status_col;
61 extern int auto_wrap, ignaw;
62 extern int bo_s_width, bo_e_width;
63 extern int ul_s_width, ul_e_width;
64 extern int bl_s_width, bl_e_width;
65 extern int so_s_width, so_e_width;
66 extern int sc_width, sc_height;
67 extern int utf_mode;
68 extern POSITION start_attnpos;
69 extern POSITION end_attnpos;
70 extern char rscroll_char;
71 extern int rscroll_attr;
72
73 static char mbc_buf[MAX_UTF_CHAR_LEN];
74 static int mbc_buf_len = 0;
75 static int mbc_buf_index = 0;
76 static POSITION mbc_pos;
77
78 /*
79 * Initialize from environment variables.
80 */
81 public void
init_line(VOID_PARAM)82 init_line(VOID_PARAM)
83 {
84 end_ansi_chars = lgetenv("LESSANSIENDCHARS");
85 if (isnullenv(end_ansi_chars))
86 end_ansi_chars = "m";
87
88 mid_ansi_chars = lgetenv("LESSANSIMIDCHARS");
89 if (isnullenv(mid_ansi_chars))
90 mid_ansi_chars = "0123456789:;[?!\"'#%()*+ ";
91
92 linebuf = (char *) ecalloc(LINEBUF_SIZE, sizeof(char));
93 attr = (char *) ecalloc(LINEBUF_SIZE, sizeof(char));
94 size_linebuf = LINEBUF_SIZE;
95 }
96
97 /*
98 * Expand the line buffer.
99 */
100 static int
expand_linebuf(VOID_PARAM)101 expand_linebuf(VOID_PARAM)
102 {
103 /* Double the size of the line buffer. */
104 int new_size = size_linebuf * 2;
105
106 /* Just realloc to expand the buffer, if we can. */
107 #if HAVE_REALLOC
108 char *new_buf = (char *) realloc(linebuf, new_size);
109 char *new_attr = (char *) realloc(attr, new_size);
110 #else
111 char *new_buf = (char *) calloc(new_size, sizeof(char));
112 char *new_attr = (char *) calloc(new_size, sizeof(char));
113 #endif
114 if (new_buf == NULL || new_attr == NULL)
115 {
116 if (new_attr != NULL)
117 free(new_attr);
118 if (new_buf != NULL)
119 free(new_buf);
120 return 1;
121 }
122 #if !HAVE_REALLOC
123 /*
124 * We just calloc'd the buffers; copy the old contents.
125 */
126 memcpy(new_buf, linebuf, size_linebuf * sizeof(char));
127 memcpy(new_attr, attr, size_linebuf * sizeof(char));
128 free(attr);
129 free(linebuf);
130 #endif
131 linebuf = new_buf;
132 attr = new_attr;
133 size_linebuf = new_size;
134 return 0;
135 }
136
137 /*
138 * Is a character ASCII?
139 */
140 public int
is_ascii_char(ch)141 is_ascii_char(ch)
142 LWCHAR ch;
143 {
144 return (ch <= 0x7F);
145 }
146
147 /*
148 * Rewind the line buffer.
149 */
150 public void
prewind(VOID_PARAM)151 prewind(VOID_PARAM)
152 {
153 curr = 0;
154 column = 0;
155 right_curr = 0;
156 right_column = 0;
157 cshift = 0;
158 overstrike = 0;
159 last_overstrike = AT_NORMAL;
160 mbc_buf_len = 0;
161 is_null_line = 0;
162 pendc = '\0';
163 lmargin = 0;
164 if (status_col)
165 lmargin += 2;
166 }
167
168 /*
169 * Set a character in the line buffer.
170 */
171 static void
set_linebuf(n,ch,a)172 set_linebuf(n, ch, a)
173 int n;
174 char ch;
175 char a;
176 {
177 linebuf[n] = ch;
178 attr[n] = a;
179 }
180
181 /*
182 * Append a character to the line buffer.
183 */
184 static void
add_linebuf(ch,a,w)185 add_linebuf(ch, a, w)
186 char ch;
187 char a;
188 int w;
189 {
190 set_linebuf(curr++, ch, a);
191 column += w;
192 }
193
194 /*
195 * Insert the line number (of the given position) into the line buffer.
196 */
197 public void
plinenum(pos)198 plinenum(pos)
199 POSITION pos;
200 {
201 LINENUM linenum = 0;
202 int i;
203
204 if (linenums == OPT_ONPLUS)
205 {
206 /*
207 * Get the line number and put it in the current line.
208 * {{ Note: since find_linenum calls forw_raw_line,
209 * it may seek in the input file, requiring the caller
210 * of plinenum to re-seek if necessary. }}
211 * {{ Since forw_raw_line modifies linebuf, we must
212 * do this first, before storing anything in linebuf. }}
213 */
214 linenum = find_linenum(pos);
215 }
216
217 /*
218 * Display a status column if the -J option is set.
219 */
220 if (status_col)
221 {
222 int a = AT_NORMAL;
223 char c = posmark(pos);
224 if (c != 0)
225 a |= AT_HILITE;
226 else
227 {
228 c = ' ';
229 if (start_attnpos != NULL_POSITION &&
230 pos >= start_attnpos && pos <= end_attnpos)
231 a |= AT_HILITE;
232 }
233 add_linebuf(c, a, 1); /* column 0: status */
234 add_linebuf(' ', AT_NORMAL, 1); /* column 1: empty */
235 }
236
237 /*
238 * Display the line number at the start of each line
239 * if the -N option is set.
240 */
241 if (linenums == OPT_ONPLUS)
242 {
243 char buf[INT_STRLEN_BOUND(linenum) + 2];
244 int pad = 0;
245 int n;
246
247 linenumtoa(linenum, buf);
248 n = (int) strlen(buf);
249 if (n < MIN_LINENUM_WIDTH)
250 pad = MIN_LINENUM_WIDTH - n;
251 for (i = 0; i < pad; i++)
252 add_linebuf(' ', AT_NORMAL, 1);
253 for (i = 0; i < n; i++)
254 add_linebuf(buf[i], AT_BOLD, 1);
255 add_linebuf(' ', AT_NORMAL, 1);
256 lmargin += n + pad + 1;
257 }
258 /*
259 * Append enough spaces to bring us to the lmargin.
260 */
261 while (column < lmargin)
262 {
263 add_linebuf(' ', AT_NORMAL, 1);
264 }
265 }
266
267 /*
268 * Shift the input line left.
269 * This means discarding N printable chars at the start of the buffer.
270 */
271 static void
pshift(shift)272 pshift(shift)
273 int shift;
274 {
275 LWCHAR prev_ch = 0;
276 unsigned char c;
277 int shifted = 0;
278 int to;
279 int from;
280 int len;
281 int width;
282 int prev_attr;
283 int next_attr;
284
285 if (shift > column - lmargin)
286 shift = column - lmargin;
287 if (shift > curr - lmargin)
288 shift = curr - lmargin;
289
290 to = from = lmargin;
291 /*
292 * We keep on going when shifted == shift
293 * to get all combining chars.
294 */
295 while (shifted <= shift && from < curr)
296 {
297 c = linebuf[from];
298 if (ctldisp == OPT_ONPLUS && IS_CSI_START(c))
299 {
300 /* Keep cumulative effect. */
301 linebuf[to] = c;
302 attr[to++] = attr[from++];
303 while (from < curr && linebuf[from])
304 {
305 linebuf[to] = linebuf[from];
306 attr[to++] = attr[from];
307 if (!is_ansi_middle(linebuf[from++]))
308 break;
309 }
310 continue;
311 }
312
313 width = 0;
314
315 if (!IS_ASCII_OCTET(c) && utf_mode)
316 {
317 /* Assumes well-formedness validation already done. */
318 LWCHAR ch;
319
320 len = utf_len(c);
321 if (from + len > curr)
322 break;
323 ch = get_wchar(linebuf + from);
324 if (!is_composing_char(ch) && !is_combining_char(prev_ch, ch))
325 width = is_wide_char(ch) ? 2 : 1;
326 prev_ch = ch;
327 } else
328 {
329 len = 1;
330 if (c == '\b')
331 /* XXX - Incorrect if several '\b' in a row. */
332 width = (utf_mode && is_wide_char(prev_ch)) ? -2 : -1;
333 else if (!control_char(c))
334 width = 1;
335 prev_ch = 0;
336 }
337
338 if (width == 2 && shift - shifted == 1) {
339 /* Should never happen when called by pshift_all(). */
340 attr[to] = attr[from];
341 /*
342 * Assume a wide_char will never be the first half of a
343 * combining_char pair, so reset prev_ch in case we're
344 * followed by a '\b'.
345 */
346 prev_ch = linebuf[to++] = ' ';
347 from += len;
348 shifted++;
349 continue;
350 }
351
352 /* Adjust width for magic cookies. */
353 prev_attr = (to > 0) ? attr[to-1] : AT_NORMAL;
354 next_attr = (from + len < curr) ? attr[from + len] : prev_attr;
355 if (!is_at_equiv(attr[from], prev_attr) &&
356 !is_at_equiv(attr[from], next_attr))
357 {
358 width += attr_swidth(attr[from]);
359 if (from + len < curr)
360 width += attr_ewidth(attr[from]);
361 if (is_at_equiv(prev_attr, next_attr))
362 {
363 width += attr_ewidth(prev_attr);
364 if (from + len < curr)
365 width += attr_swidth(next_attr);
366 }
367 }
368
369 if (shift - shifted < width)
370 break;
371 from += len;
372 shifted += width;
373 if (shifted < 0)
374 shifted = 0;
375 }
376 while (from < curr)
377 {
378 linebuf[to] = linebuf[from];
379 attr[to++] = attr[from++];
380 }
381 curr = to;
382 column -= shifted;
383 cshift += shifted;
384 }
385
386 /*
387 *
388 */
389 public void
pshift_all(VOID_PARAM)390 pshift_all(VOID_PARAM)
391 {
392 pshift(column);
393 }
394
395 /*
396 * Return the printing width of the start (enter) sequence
397 * for a given character attribute.
398 */
399 static int
attr_swidth(a)400 attr_swidth(a)
401 int a;
402 {
403 int w = 0;
404
405 a = apply_at_specials(a);
406
407 if (a & AT_UNDERLINE)
408 w += ul_s_width;
409 if (a & AT_BOLD)
410 w += bo_s_width;
411 if (a & AT_BLINK)
412 w += bl_s_width;
413 if (a & AT_STANDOUT)
414 w += so_s_width;
415
416 return w;
417 }
418
419 /*
420 * Return the printing width of the end (exit) sequence
421 * for a given character attribute.
422 */
423 static int
attr_ewidth(a)424 attr_ewidth(a)
425 int a;
426 {
427 int w = 0;
428
429 a = apply_at_specials(a);
430
431 if (a & AT_UNDERLINE)
432 w += ul_e_width;
433 if (a & AT_BOLD)
434 w += bo_e_width;
435 if (a & AT_BLINK)
436 w += bl_e_width;
437 if (a & AT_STANDOUT)
438 w += so_e_width;
439
440 return w;
441 }
442
443 /*
444 * Return the printing width of a given character and attribute,
445 * if the character were added to the current position in the line buffer.
446 * Adding a character with a given attribute may cause an enter or exit
447 * attribute sequence to be inserted, so this must be taken into account.
448 */
449 static int
pwidth(ch,a,prev_ch)450 pwidth(ch, a, prev_ch)
451 LWCHAR ch;
452 int a;
453 LWCHAR prev_ch;
454 {
455 int w;
456
457 if (ch == '\b')
458 /*
459 * Backspace moves backwards one or two positions.
460 * XXX - Incorrect if several '\b' in a row.
461 */
462 return (utf_mode && is_wide_char(prev_ch)) ? -2 : -1;
463
464 if (!utf_mode || is_ascii_char(ch))
465 {
466 if (control_char((char)ch))
467 {
468 /*
469 * Control characters do unpredictable things,
470 * so we don't even try to guess; say it doesn't move.
471 * This can only happen if the -r flag is in effect.
472 */
473 return (0);
474 }
475 } else
476 {
477 if (is_composing_char(ch) || is_combining_char(prev_ch, ch))
478 {
479 /*
480 * Composing and combining chars take up no space.
481 *
482 * Some terminals, upon failure to compose a
483 * composing character with the character(s) that
484 * precede(s) it will actually take up one column
485 * for the composing character; there isn't much
486 * we could do short of testing the (complex)
487 * composition process ourselves and printing
488 * a binary representation when it fails.
489 */
490 return (0);
491 }
492 }
493
494 /*
495 * Other characters take one or two columns,
496 * plus the width of any attribute enter/exit sequence.
497 */
498 w = 1;
499 if (is_wide_char(ch))
500 w++;
501 if (curr > 0 && !is_at_equiv(attr[curr-1], a))
502 w += attr_ewidth(attr[curr-1]);
503 if ((apply_at_specials(a) != AT_NORMAL) &&
504 (curr == 0 || !is_at_equiv(attr[curr-1], a)))
505 w += attr_swidth(a);
506 return (w);
507 }
508
509 /*
510 * Delete to the previous base character in the line buffer.
511 * Return 1 if one is found.
512 */
513 static int
backc(VOID_PARAM)514 backc(VOID_PARAM)
515 {
516 LWCHAR prev_ch;
517 char *p = linebuf + curr;
518 LWCHAR ch = step_char(&p, -1, linebuf + lmargin);
519 int width;
520
521 /* This assumes that there is no '\b' in linebuf. */
522 while ( curr > lmargin
523 && column > lmargin
524 && (!(attr[curr - 1] & (AT_ANSI|AT_BINARY))))
525 {
526 curr = (int) (p - linebuf);
527 prev_ch = step_char(&p, -1, linebuf + lmargin);
528 width = pwidth(ch, attr[curr], prev_ch);
529 column -= width;
530 if (width > 0)
531 return 1;
532 ch = prev_ch;
533 }
534
535 return 0;
536 }
537
538 /*
539 * Are we currently within a recognized ANSI escape sequence?
540 */
541 static int
in_ansi_esc_seq(VOID_PARAM)542 in_ansi_esc_seq(VOID_PARAM)
543 {
544 char *p;
545
546 /*
547 * Search backwards for either an ESC (which means we ARE in a seq);
548 * or an end char (which means we're NOT in a seq).
549 */
550 for (p = &linebuf[curr]; p > linebuf; )
551 {
552 LWCHAR ch = step_char(&p, -1, linebuf);
553 if (IS_CSI_START(ch))
554 return (1);
555 if (!is_ansi_middle(ch))
556 return (0);
557 }
558 return (0);
559 }
560
561 /*
562 * Is a character the end of an ANSI escape sequence?
563 */
564 public int
is_ansi_end(ch)565 is_ansi_end(ch)
566 LWCHAR ch;
567 {
568 if (!is_ascii_char(ch))
569 return (0);
570 return (strchr(end_ansi_chars, (char) ch) != NULL);
571 }
572
573 /*
574 * Can a char appear in an ANSI escape sequence, before the end char?
575 */
576 public int
is_ansi_middle(ch)577 is_ansi_middle(ch)
578 LWCHAR ch;
579 {
580 if (!is_ascii_char(ch))
581 return (0);
582 if (is_ansi_end(ch))
583 return (0);
584 return (strchr(mid_ansi_chars, (char) ch) != NULL);
585 }
586
587 /*
588 * Skip past an ANSI escape sequence.
589 * pp is initially positioned just after the CSI_START char.
590 */
591 public void
skip_ansi(pp,limit)592 skip_ansi(pp, limit)
593 char **pp;
594 constant char *limit;
595 {
596 LWCHAR c;
597 do {
598 c = step_char(pp, +1, limit);
599 } while (*pp < limit && is_ansi_middle(c));
600 /* Note that we discard final char, for which is_ansi_middle is false. */
601 }
602
603
604 /*
605 * Append a character and attribute to the line buffer.
606 */
607 #define STORE_CHAR(ch,a,rep,pos) \
608 do { \
609 if (store_char((ch),(a),(rep),(pos))) return (1); \
610 } while (0)
611
612 static int
store_char(ch,a,rep,pos)613 store_char(ch, a, rep, pos)
614 LWCHAR ch;
615 int a;
616 char *rep;
617 POSITION pos;
618 {
619 int w;
620 int replen;
621 char cs;
622
623 w = (a & (AT_UNDERLINE|AT_BOLD)); /* Pre-use w. */
624 if (w != AT_NORMAL)
625 last_overstrike = w;
626
627 #if HILITE_SEARCH
628 {
629 int matches;
630 if (is_hilited(pos, pos+1, 0, &matches))
631 {
632 /*
633 * This character should be highlighted.
634 * Override the attribute passed in.
635 */
636 if (a != AT_ANSI)
637 {
638 if (highest_hilite != NULL_POSITION &&
639 pos > highest_hilite)
640 highest_hilite = pos;
641 a |= AT_HILITE;
642 }
643 }
644 }
645 #endif
646
647 if (ctldisp == OPT_ONPLUS && in_ansi_esc_seq())
648 {
649 if (!is_ansi_end(ch) && !is_ansi_middle(ch)) {
650 /* Remove whole unrecognized sequence. */
651 char *p = &linebuf[curr];
652 LWCHAR bch;
653 do {
654 bch = step_char(&p, -1, linebuf);
655 } while (p > linebuf && !IS_CSI_START(bch));
656 curr = (int) (p - linebuf);
657 return 0;
658 }
659 a = AT_ANSI; /* Will force re-AT_'ing around it. */
660 w = 0;
661 }
662 else if (ctldisp == OPT_ONPLUS && IS_CSI_START(ch))
663 {
664 a = AT_ANSI; /* Will force re-AT_'ing around it. */
665 w = 0;
666 }
667 else
668 {
669 char *p = &linebuf[curr];
670 LWCHAR prev_ch = step_char(&p, -1, linebuf);
671 w = pwidth(ch, a, prev_ch);
672 }
673
674 if (ctldisp != OPT_ON && column + w + attr_ewidth(a) > sc_width)
675 /*
676 * Won't fit on screen.
677 */
678 return (1);
679
680 if (rep == NULL)
681 {
682 cs = (char) ch;
683 rep = &cs;
684 replen = 1;
685 } else
686 {
687 replen = utf_len(rep[0]);
688 }
689 if (curr + replen >= size_linebuf-6)
690 {
691 /*
692 * Won't fit in line buffer.
693 * Try to expand it.
694 */
695 if (expand_linebuf())
696 return (1);
697 }
698
699 if (column > right_column && w > 0)
700 {
701 right_column = column;
702 right_curr = curr;
703 }
704
705 while (replen-- > 0)
706 {
707 add_linebuf(*rep++, a, 0);
708 }
709 column += w;
710 return (0);
711 }
712
713 /*
714 * Append a tab to the line buffer.
715 * Store spaces to represent the tab.
716 */
717 #define STORE_TAB(a,pos) \
718 do { if (store_tab((a),(pos))) return (1); } while (0)
719
720 static int
store_tab(attr,pos)721 store_tab(attr, pos)
722 int attr;
723 POSITION pos;
724 {
725 int to_tab = column + cshift - lmargin;
726 int i;
727
728 if (ntabstops < 2 || to_tab >= tabstops[ntabstops-1])
729 to_tab = tabdefault -
730 ((to_tab - tabstops[ntabstops-1]) % tabdefault);
731 else
732 {
733 for (i = ntabstops - 2; i >= 0; i--)
734 if (to_tab >= tabstops[i])
735 break;
736 to_tab = tabstops[i+1] - to_tab;
737 }
738
739 if (column + to_tab - 1 + pwidth(' ', attr, 0) + attr_ewidth(attr) > sc_width)
740 return 1;
741
742 do {
743 STORE_CHAR(' ', attr, " ", pos);
744 } while (--to_tab > 0);
745 return 0;
746 }
747
748 #define STORE_PRCHAR(c, pos) \
749 do { if (store_prchar((c), (pos))) return 1; } while (0)
750
751 static int
store_prchar(c,pos)752 store_prchar(c, pos)
753 LWCHAR c;
754 POSITION pos;
755 {
756 char *s;
757
758 /*
759 * Convert to printable representation.
760 */
761 s = prchar(c);
762
763 /*
764 * Make sure we can get the entire representation
765 * of the character on this line.
766 */
767 if (column + (int) strlen(s) - 1 +
768 pwidth(' ', binattr, 0) + attr_ewidth(binattr) > sc_width)
769 return 1;
770
771 for ( ; *s != 0; s++)
772 STORE_CHAR(*s, AT_BINARY, NULL, pos);
773
774 return 0;
775 }
776
777 static int
flush_mbc_buf(pos)778 flush_mbc_buf(pos)
779 POSITION pos;
780 {
781 int i;
782
783 for (i = 0; i < mbc_buf_index; i++)
784 if (store_prchar(mbc_buf[i], pos))
785 return mbc_buf_index - i;
786
787 return 0;
788 }
789
790 /*
791 * Append a character to the line buffer.
792 * Expand tabs into spaces, handle underlining, boldfacing, etc.
793 * Returns 0 if ok, 1 if couldn't fit in buffer.
794 */
795 public int
pappend(c,pos)796 pappend(c, pos)
797 unsigned char c;
798 POSITION pos;
799 {
800 int r;
801
802 if (pendc)
803 {
804 if (c == '\r' && pendc == '\r')
805 return (0);
806 if (do_append(pendc, NULL, pendpos))
807 /*
808 * Oops. We've probably lost the char which
809 * was in pendc, since caller won't back up.
810 */
811 return (1);
812 pendc = '\0';
813 }
814
815 if (c == '\r' && bs_mode == BS_SPECIAL)
816 {
817 if (mbc_buf_len > 0) /* utf_mode must be on. */
818 {
819 /* Flush incomplete (truncated) sequence. */
820 r = flush_mbc_buf(mbc_pos);
821 mbc_buf_index = r + 1;
822 mbc_buf_len = 0;
823 if (r)
824 return (mbc_buf_index);
825 }
826
827 /*
828 * Don't put the CR into the buffer until we see
829 * the next char. If the next char is a newline,
830 * discard the CR.
831 */
832 pendc = c;
833 pendpos = pos;
834 return (0);
835 }
836
837 if (!utf_mode)
838 {
839 r = do_append(c, NULL, pos);
840 } else
841 {
842 /* Perform strict validation in all possible cases. */
843 if (mbc_buf_len == 0)
844 {
845 retry:
846 mbc_buf_index = 1;
847 *mbc_buf = c;
848 if (IS_ASCII_OCTET(c))
849 r = do_append(c, NULL, pos);
850 else if (IS_UTF8_LEAD(c))
851 {
852 mbc_buf_len = utf_len(c);
853 mbc_pos = pos;
854 return (0);
855 } else
856 /* UTF8_INVALID or stray UTF8_TRAIL */
857 r = flush_mbc_buf(pos);
858 } else if (IS_UTF8_TRAIL(c))
859 {
860 mbc_buf[mbc_buf_index++] = c;
861 if (mbc_buf_index < mbc_buf_len)
862 return (0);
863 if (is_utf8_well_formed(mbc_buf, mbc_buf_index))
864 r = do_append(get_wchar(mbc_buf), mbc_buf, mbc_pos);
865 else
866 /* Complete, but not shortest form, sequence. */
867 mbc_buf_index = r = flush_mbc_buf(mbc_pos);
868 mbc_buf_len = 0;
869 } else
870 {
871 /* Flush incomplete (truncated) sequence. */
872 r = flush_mbc_buf(mbc_pos);
873 mbc_buf_index = r + 1;
874 mbc_buf_len = 0;
875 /* Handle new char. */
876 if (!r)
877 goto retry;
878 }
879 }
880
881 /*
882 * If we need to shift the line, do it.
883 * But wait until we get to at least the middle of the screen,
884 * so shifting it doesn't affect the chars we're currently
885 * pappending. (Bold & underline can get messed up otherwise.)
886 */
887 if (cshift < hshift && column > sc_width / 2)
888 {
889 linebuf[curr] = '\0';
890 pshift(hshift - cshift);
891 }
892 if (r)
893 {
894 /* How many chars should caller back up? */
895 r = (!utf_mode) ? 1 : mbc_buf_index;
896 }
897 return (r);
898 }
899
900 static int
do_append(ch,rep,pos)901 do_append(ch, rep, pos)
902 LWCHAR ch;
903 char *rep;
904 POSITION pos;
905 {
906 int a;
907 LWCHAR prev_ch;
908
909 a = AT_NORMAL;
910
911 if (ch == '\b')
912 {
913 if (bs_mode == BS_CONTROL)
914 goto do_control_char;
915
916 /*
917 * A better test is needed here so we don't
918 * backspace over part of the printed
919 * representation of a binary character.
920 */
921 if ( curr <= lmargin
922 || column <= lmargin
923 || (attr[curr - 1] & (AT_ANSI|AT_BINARY)))
924 STORE_PRCHAR('\b', pos);
925 else if (bs_mode == BS_NORMAL)
926 STORE_CHAR(ch, AT_NORMAL, NULL, pos);
927 else if (bs_mode == BS_SPECIAL)
928 overstrike = backc();
929
930 return 0;
931 }
932
933 if (overstrike > 0)
934 {
935 /*
936 * Overstrike the character at the current position
937 * in the line buffer. This will cause either
938 * underline (if a "_" is overstruck),
939 * bold (if an identical character is overstruck),
940 * or just deletion of the character in the buffer.
941 */
942 overstrike = utf_mode ? -1 : 0;
943 if (utf_mode)
944 {
945 /* To be correct, this must be a base character. */
946 prev_ch = get_wchar(linebuf + curr);
947 } else
948 {
949 prev_ch = (unsigned char) linebuf[curr];
950 }
951 a = attr[curr];
952 if (ch == prev_ch)
953 {
954 /*
955 * Overstriking a char with itself means make it bold.
956 * But overstriking an underscore with itself is
957 * ambiguous. It could mean make it bold, or
958 * it could mean make it underlined.
959 * Use the previous overstrike to resolve it.
960 */
961 if (ch == '_')
962 {
963 if ((a & (AT_BOLD|AT_UNDERLINE)) != AT_NORMAL)
964 a |= (AT_BOLD|AT_UNDERLINE);
965 else if (last_overstrike != AT_NORMAL)
966 a |= last_overstrike;
967 else
968 a |= AT_BOLD;
969 } else
970 a |= AT_BOLD;
971 } else if (ch == '_')
972 {
973 a |= AT_UNDERLINE;
974 ch = prev_ch;
975 rep = linebuf + curr;
976 } else if (prev_ch == '_')
977 {
978 a |= AT_UNDERLINE;
979 }
980 /* Else we replace prev_ch, but we keep its attributes. */
981 } else if (overstrike < 0)
982 {
983 if ( is_composing_char(ch)
984 || is_combining_char(get_wchar(linebuf + curr), ch))
985 /* Continuation of the same overstrike. */
986 a = last_overstrike;
987 else
988 overstrike = 0;
989 }
990
991 if (ch == '\t')
992 {
993 /*
994 * Expand a tab into spaces.
995 */
996 switch (bs_mode)
997 {
998 case BS_CONTROL:
999 goto do_control_char;
1000 case BS_NORMAL:
1001 case BS_SPECIAL:
1002 STORE_TAB(a, pos);
1003 break;
1004 }
1005 } else if ((!utf_mode || is_ascii_char(ch)) && control_char((char)ch))
1006 {
1007 do_control_char:
1008 if (ctldisp == OPT_ON || (ctldisp == OPT_ONPLUS && IS_CSI_START(ch)))
1009 {
1010 /*
1011 * Output as a normal character.
1012 */
1013 STORE_CHAR(ch, AT_NORMAL, rep, pos);
1014 } else
1015 {
1016 STORE_PRCHAR((char) ch, pos);
1017 }
1018 } else if (utf_mode && ctldisp != OPT_ON && is_ubin_char(ch))
1019 {
1020 char *s;
1021
1022 s = prutfchar(ch);
1023
1024 if (column + (int) strlen(s) - 1 +
1025 pwidth(' ', binattr, 0) + attr_ewidth(binattr) > sc_width)
1026 return (1);
1027
1028 for ( ; *s != 0; s++)
1029 STORE_CHAR(*s, AT_BINARY, NULL, pos);
1030 } else
1031 {
1032 STORE_CHAR(ch, a, rep, pos);
1033 }
1034 return (0);
1035 }
1036
1037 /*
1038 *
1039 */
1040 public int
pflushmbc(VOID_PARAM)1041 pflushmbc(VOID_PARAM)
1042 {
1043 int r = 0;
1044
1045 if (mbc_buf_len > 0)
1046 {
1047 /* Flush incomplete (truncated) sequence. */
1048 r = flush_mbc_buf(mbc_pos);
1049 mbc_buf_len = 0;
1050 }
1051 return r;
1052 }
1053
1054 /*
1055 * Switch to normal attribute at end of line.
1056 */
1057 static void
add_attr_normal(VOID_PARAM)1058 add_attr_normal(VOID_PARAM)
1059 {
1060 char *p = "\033[m";
1061
1062 if (ctldisp != OPT_ONPLUS || !is_ansi_end('m'))
1063 return;
1064 for ( ; *p != '\0'; p++)
1065 add_linebuf(*p, AT_ANSI, 0);
1066 }
1067
1068 /*
1069 * Terminate the line in the line buffer.
1070 */
1071 public void
pdone(endline,chopped,forw)1072 pdone(endline, chopped, forw)
1073 int endline;
1074 int chopped;
1075 int forw;
1076 {
1077 (void) pflushmbc();
1078
1079 if (pendc && (pendc != '\r' || !endline))
1080 /*
1081 * If we had a pending character, put it in the buffer.
1082 * But discard a pending CR if we are at end of line
1083 * (that is, discard the CR in a CR/LF sequence).
1084 */
1085 (void) do_append(pendc, NULL, pendpos);
1086
1087 /*
1088 * Make sure we've shifted the line, if we need to.
1089 */
1090 if (cshift < hshift)
1091 pshift(hshift - cshift);
1092
1093 if (chopped && rscroll_char)
1094 {
1095 /*
1096 * Display the right scrolling char.
1097 * If we've already filled the rightmost screen char
1098 * (in the buffer), overwrite it.
1099 */
1100 if (column >= sc_width)
1101 {
1102 /* We've already written in the rightmost char. */
1103 column = right_column;
1104 curr = right_curr;
1105 }
1106 add_attr_normal();
1107 while (column < sc_width-1)
1108 {
1109 /*
1110 * Space to last (rightmost) char on screen.
1111 * This may be necessary if the char we overwrote
1112 * was double-width.
1113 */
1114 add_linebuf(' ', AT_NORMAL, 1);
1115 }
1116 /* Print rscroll char. It must be single-width. */
1117 add_linebuf(rscroll_char, rscroll_attr, 1);
1118 } else
1119 {
1120 add_attr_normal();
1121 }
1122
1123 /*
1124 * Add a newline if necessary,
1125 * and append a '\0' to the end of the line.
1126 * We output a newline if we're not at the right edge of the screen,
1127 * or if the terminal doesn't auto wrap,
1128 * or if this is really the end of the line AND the terminal ignores
1129 * a newline at the right edge.
1130 * (In the last case we don't want to output a newline if the terminal
1131 * doesn't ignore it since that would produce an extra blank line.
1132 * But we do want to output a newline if the terminal ignores it in case
1133 * the next line is blank. In that case the single newline output for
1134 * that blank line would be ignored!)
1135 */
1136 if (column < sc_width || !auto_wrap || (endline && ignaw) || ctldisp == OPT_ON)
1137 {
1138 add_linebuf('\n', AT_NORMAL, 0);
1139 }
1140 else if (ignaw && column >= sc_width && forw)
1141 {
1142 /*
1143 * Terminals with "ignaw" don't wrap until they *really* need
1144 * to, i.e. when the character *after* the last one to fit on a
1145 * line is output. But they are too hard to deal with when they
1146 * get in the state where a full screen width of characters
1147 * have been output but the cursor is sitting on the right edge
1148 * instead of at the start of the next line.
1149 * So we nudge them into wrapping by outputting a space
1150 * character plus a backspace. But do this only if moving
1151 * forward; if we're moving backward and drawing this line at
1152 * the top of the screen, the space would overwrite the first
1153 * char on the next line. We don't need to do this "nudge"
1154 * at the top of the screen anyway.
1155 */
1156 add_linebuf(' ', AT_NORMAL, 1);
1157 add_linebuf('\b', AT_NORMAL, -1);
1158 }
1159 set_linebuf(curr, '\0', AT_NORMAL);
1160 }
1161
1162 /*
1163 *
1164 */
1165 public void
set_status_col(c)1166 set_status_col(c)
1167 char c;
1168 {
1169 set_linebuf(0, c, AT_NORMAL|AT_HILITE);
1170 }
1171
1172 /*
1173 * Get a character from the current line.
1174 * Return the character as the function return value,
1175 * and the character attribute in *ap.
1176 */
1177 public int
gline(i,ap)1178 gline(i, ap)
1179 int i;
1180 int *ap;
1181 {
1182 if (is_null_line)
1183 {
1184 /*
1185 * If there is no current line, we pretend the line is
1186 * either "~" or "", depending on the "twiddle" flag.
1187 */
1188 if (twiddle)
1189 {
1190 if (i == 0)
1191 {
1192 *ap = AT_BOLD;
1193 return '~';
1194 }
1195 --i;
1196 }
1197 /* Make sure we're back to AT_NORMAL before the '\n'. */
1198 *ap = AT_NORMAL;
1199 return i ? '\0' : '\n';
1200 }
1201
1202 *ap = attr[i];
1203 return (linebuf[i] & 0xFF);
1204 }
1205
1206 /*
1207 * Indicate that there is no current line.
1208 */
1209 public void
null_line(VOID_PARAM)1210 null_line(VOID_PARAM)
1211 {
1212 is_null_line = 1;
1213 cshift = 0;
1214 }
1215
1216 /*
1217 * Analogous to forw_line(), but deals with "raw lines":
1218 * lines which are not split for screen width.
1219 * {{ This is supposed to be more efficient than forw_line(). }}
1220 */
1221 public POSITION
forw_raw_line(curr_pos,linep,line_lenp)1222 forw_raw_line(curr_pos, linep, line_lenp)
1223 POSITION curr_pos;
1224 char **linep;
1225 int *line_lenp;
1226 {
1227 int n;
1228 int c;
1229 POSITION new_pos;
1230
1231 if (curr_pos == NULL_POSITION || ch_seek(curr_pos) ||
1232 (c = ch_forw_get()) == EOI)
1233 return (NULL_POSITION);
1234
1235 n = 0;
1236 for (;;)
1237 {
1238 if (c == '\n' || c == EOI || ABORT_SIGS())
1239 {
1240 new_pos = ch_tell();
1241 break;
1242 }
1243 if (n >= size_linebuf-1)
1244 {
1245 if (expand_linebuf())
1246 {
1247 /*
1248 * Overflowed the input buffer.
1249 * Pretend the line ended here.
1250 */
1251 new_pos = ch_tell() - 1;
1252 break;
1253 }
1254 }
1255 linebuf[n++] = c;
1256 c = ch_forw_get();
1257 }
1258 linebuf[n] = '\0';
1259 if (linep != NULL)
1260 *linep = linebuf;
1261 if (line_lenp != NULL)
1262 *line_lenp = n;
1263 return (new_pos);
1264 }
1265
1266 /*
1267 * Analogous to back_line(), but deals with "raw lines".
1268 * {{ This is supposed to be more efficient than back_line(). }}
1269 */
1270 public POSITION
back_raw_line(curr_pos,linep,line_lenp)1271 back_raw_line(curr_pos, linep, line_lenp)
1272 POSITION curr_pos;
1273 char **linep;
1274 int *line_lenp;
1275 {
1276 int n;
1277 int c;
1278 POSITION new_pos;
1279
1280 if (curr_pos == NULL_POSITION || curr_pos <= ch_zero() ||
1281 ch_seek(curr_pos-1))
1282 return (NULL_POSITION);
1283
1284 n = size_linebuf;
1285 linebuf[--n] = '\0';
1286 for (;;)
1287 {
1288 c = ch_back_get();
1289 if (c == '\n' || ABORT_SIGS())
1290 {
1291 /*
1292 * This is the newline ending the previous line.
1293 * We have hit the beginning of the line.
1294 */
1295 new_pos = ch_tell() + 1;
1296 break;
1297 }
1298 if (c == EOI)
1299 {
1300 /*
1301 * We have hit the beginning of the file.
1302 * This must be the first line in the file.
1303 * This must, of course, be the beginning of the line.
1304 */
1305 new_pos = ch_zero();
1306 break;
1307 }
1308 if (n <= 0)
1309 {
1310 int old_size_linebuf = size_linebuf;
1311 char *fm;
1312 char *to;
1313 if (expand_linebuf())
1314 {
1315 /*
1316 * Overflowed the input buffer.
1317 * Pretend the line ended here.
1318 */
1319 new_pos = ch_tell() + 1;
1320 break;
1321 }
1322 /*
1323 * Shift the data to the end of the new linebuf.
1324 */
1325 for (fm = linebuf + old_size_linebuf - 1,
1326 to = linebuf + size_linebuf - 1;
1327 fm >= linebuf; fm--, to--)
1328 *to = *fm;
1329 n = size_linebuf - old_size_linebuf;
1330 }
1331 linebuf[--n] = c;
1332 }
1333 if (linep != NULL)
1334 *linep = &linebuf[n];
1335 if (line_lenp != NULL)
1336 *line_lenp = size_linebuf - 1 - n;
1337 return (new_pos);
1338 }
1339
1340 /*
1341 * Find the shift necessary to show the end of the longest displayed line.
1342 */
1343 public int
rrshift(VOID_PARAM)1344 rrshift(VOID_PARAM)
1345 {
1346 POSITION pos;
1347 int save_width;
1348 int line;
1349 int longest = 0;
1350
1351 save_width = sc_width;
1352 sc_width = INT_MAX;
1353 hshift = 0;
1354 pos = position(TOP);
1355 for (line = 0; line < sc_height && pos != NULL_POSITION; line++)
1356 {
1357 pos = forw_line(pos);
1358 if (column > longest)
1359 longest = column;
1360 }
1361 sc_width = save_width;
1362 if (longest < sc_width)
1363 return 0;
1364 return longest - sc_width;
1365 }
1366