about summary refs log tree commit diff
path: root/Src/Zle/zle_refresh.c
blob: c33c26119027841199269693b7bf32cadce957de (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
/*
 * zle_refresh.c - screen update
 *
 * This file is part of zsh, the Z shell.
 *
 * Copyright (c) 1992-1997 Paul Falstad
 * All rights reserved.
 *
 * Permission is hereby granted, without written agreement and without
 * license or royalty fees, to use, copy, modify, and distribute this
 * software and to distribute modified versions of this software for any
 * purpose, provided that the above copyright notice and the following
 * two paragraphs appear in all copies of this software.
 *
 * In no event shall Paul Falstad or the Zsh Development Group be liable
 * to any party for direct, indirect, special, incidental, or consequential
 * damages arising out of the use of this software and its documentation,
 * even if Paul Falstad and the Zsh Development Group have been advised of
 * the possibility of such damage.
 *
 * Paul Falstad and the Zsh Development Group specifically disclaim any
 * warranties, including, but not limited to, the implied warranties of
 * merchantability and fitness for a particular purpose.  The software
 * provided hereunder is on an "as is" basis, and Paul Falstad and the
 * Zsh Development Group have no obligation to provide maintenance,
 * support, updates, enhancements, or modifications.
 *
 */

#include "zle.mdh"
#include "zle_refresh.pro"

/* Expanded prompts */

/**/
char *lpromptbuf, *rpromptbuf;

/* Text attributes after displaying prompts */

/**/
unsigned pmpt_attr, rpmpt_attr;

/* number of lines displayed */

/**/
mod_export int nlnct;

/* Most lines of the buffer we've shown at once with the current list *
 * showing.  == 0 if there is no list.  == -1 if a new list has just  *
 * been put on the screen.  == -2 if zrefresh() needs to put up a new *
 * list.                                                              */

/**/
mod_export int showinglist;

/* > 0 if a completion list is displayed below the prompt,
 * < 0 if a list is displayed above the prompt. */

/**/
mod_export int listshown;

/* Length of last list displayed (if it is below the prompt). */

/**/
mod_export int lastlistlen;

/* Non-zero if ALWAYS_LAST_PROMPT has been used, meaning that the *
 * screen below the buffer display should not be cleared by       *
 * zrefresh(), but should be by trashzle().                       */

/**/
mod_export int clearflag;

/* Non-zero if zrefresh() should clear the list below the prompt. */

/**/
mod_export int clearlist;

/* Zle in trashed state - updates may be subtly altered */

/**/
int trashedzle;

/*
 * Information used by PREDISPLAY and POSTDISPLAY parameters which
 * add non-editable text to that being displayed.
 */
/**/
unsigned char *predisplay, *postdisplay;
/**/
int predisplaylen, postdisplaylen;


#ifdef HAVE_SELECT
/* cost of last update */
/**/
int cost;

# define SELECT_ADD_COST(X)	cost += X
# define zputc(a, b)		putc(a, b), cost++
# define zwrite(a, b, c, d)	fwrite(a, b, c, d), cost += (b * c)
#else
# define SELECT_ADD_COST(X)
# define zputc(a, b)		putc(a, b)
# define zwrite(a, b, c, d)	fwrite(a, b, c, d)
#endif

/* Oct/Nov 94: <mason> some code savagely redesigned to fix several bugs -
   refreshline() & tc_rightcurs() majorly rewritten; zrefresh() fixed -
   I've put my fingers into just about every routine in here -
   any queries about updates to mason@primenet.com.au */

static char **nbuf = NULL,	/* new video buffer line-by-line char array */
    **obuf = NULL;		/* old video buffer line-by-line char array */
static int more_start,		/* more text before start of screen?	    */
    more_end,			/* more stuff after end of screen?	    */
    olnct,			/* previous number of lines		    */
    ovln,			/* previous video cursor position line	    */
    lpromptw, rpromptw,		/* prompt widths on screen                  */
    lpromptwof,			/* left prompt width with real end position */
    lprompth,			/* lines taken up by the prompt		    */
    rprompth,			/* right prompt height                      */
    vcs, vln,			/* video cursor position column & line	    */
    vmaxln,			/* video maximum number of lines	    */
    winw, winh, rwinh,		/* window width & height		    */
    winpos;			/* singlelinezle: line's position in window */

/**/
void
resetvideo(void)
{
    int ln;
    static int lwinw = -1, lwinh = -1;	/* last window width & height */
 
    winw = columns;  /* terminal width */
    if (termflags & TERM_SHORT)
	winh = 1;
    else
	winh = (lines < 2) ? 24 : lines;
    rwinh = lines;		/* keep the real number of lines */
    winpos = vln = vmaxln = 0;
    if (lwinw != winw || lwinh != winh) {
	if (nbuf) {
	    for (ln = 0; ln != lwinh; ln++) {
		zfree(nbuf[ln], lwinw + 2);
		zfree(obuf[ln], lwinw + 2);
	    }
	    free(nbuf);
	    free(obuf);
	}
	nbuf = (char **)zcalloc((winh + 1) * sizeof(char *));
	obuf = (char **)zcalloc((winh + 1) * sizeof(char *));
	nbuf[0] = (char *)zalloc(winw + 2);
	obuf[0] = (char *)zalloc(winw + 2);

	lwinw = winw;
	lwinh = winh;
    }
    for (ln = 0; ln != winh + 1; ln++) {
	if (nbuf[ln])
	    *nbuf[ln] = '\0';
	if (obuf[ln])
	    *obuf[ln] = '\0';
    }

    countprompt(lpromptbuf, &lpromptwof, &lprompth, 1);
    countprompt(rpromptbuf, &rpromptw, &rprompth, 0);
    if (lpromptwof != winw)
	lpromptw = lpromptwof;
    else {
	lpromptw = 0;
	lprompth++;
    }

    if (lpromptw) {
    	memset(nbuf[0], ' ', lpromptw);
	memset(obuf[0], ' ', lpromptw);
	nbuf[0][lpromptw] = obuf[0][lpromptw] = '\0';
    }

    vcs = lpromptw;
    olnct = nlnct = 0;
    if (showinglist > 0)
	showinglist = -2;
    trashedzle = 0;
}

/*
 * Nov 96: <mason> changed to single line scroll
 */

/**/
static void
scrollwindow(int tline)
{
    int t0;
    char *s;

    s = nbuf[tline];
    for (t0 = tline; t0 < winh - 1; t0++)
	nbuf[t0] = nbuf[t0 + 1];
    nbuf[winh - 1] = s;
    if (!tline)
	more_start = 1;
    return;
}

/* this is the messy part. */
/* this define belongs where it's used!!! */

#define nextline					\
{							\
    *s = '\0';						\
    if (ln != winh - 1)					\
	ln++;						\
    else {						\
	if (!canscroll)	{				\
	    if (nvln != -1 && nvln != winh - 1		\
		&& (numscrolls != onumscrolls - 1	\
		    || nvln <= winh / 2))		\
	        break;					\
	    numscrolls++;				\
	    canscroll = winh / 2;			\
	}						\
	canscroll--;					\
	scrollwindow(0);				\
	if (nvln != -1)					\
	    nvln--;					\
    }							\
    if (!nbuf[ln])					\
	nbuf[ln] = (char *)zalloc(winw + 2);		\
    s = (unsigned char *)nbuf[ln];			\
    sen = s + winw;					\
}

#define snextline					\
{							\
    *s = '\0';						\
    if (ln != winh - 1)					\
	ln++;						\
    else						\
	if (tosln > ln) {				\
	    tosln--;					\
	    if (nvln > 1) {				\
		scrollwindow(0);			\
		nvln--;					\
	    } else					\
		more_end = 1;				\
	} else if (tosln > 2 && nvln > 1) {		\
	    tosln--;					\
	    if (tosln <= nvln) {			\
		scrollwindow(0);			\
		nvln--;					\
	    } else {					\
		scrollwindow(tosln);			\
		more_end = 1;				\
	    }						\
	} else {					\
	    more_status = 1;				\
	    scrollwindow(tosln + 1);			\
	}						\
    if (!nbuf[ln])					\
	nbuf[ln] = (char *)zalloc(winw + 2);		\
    s = (unsigned char *)nbuf[ln];			\
    sen = s + winw;					\
}

static int cleareol,		/* clear to end-of-line (if can't cleareod) */
    clearf,			/* alwayslastprompt used immediately before */
    put_rpmpt,			/* whether we should display right-prompt   */
    oput_rpmpt,			/* whether displayed right-prompt last time */
    oxtabs,			/* oxtabs - tabs expand to spaces if set    */
    numscrolls, onumscrolls;

/**/
mod_export void
zrefresh(void)
{
    static int inlist;		/* avoiding recursion                        */
    int canscroll = 0,		/* number of lines we are allowed to scroll  */
	ln = 0,			/* current line we're working on	     */
	more_status = 0,	/* more stuff in status line		     */
	nvcs = 0, nvln = -1,	/* video cursor column and line		     */
	t0 = -1,		/* tmp					     */
	tosln = 0;		/* tmp in statusline stuff		     */
    unsigned char *s,		/* pointer into the video buffer	     */
	*t,			/* pointer into the real buffer		     */
	*sen,			/* pointer to end of the video buffer (eol)  */
	*scs;			/* pointer to cursor position in real buffer */
    char **qbuf;		/* tmp					     */
    unsigned char *tmpline;	/* line with added pre/post text */
    int tmpcs, tmpll;		/* ditto cursor position and line length */
    int tmpalloced;		/* flag to free tmpline when finished */
	

    /* If this is called from listmatches() (indirectly via trashzle()), and *
     * that was called from the end of zrefresh(), then we don't need to do  *
     * anything.  All this `inlist' code is actually unnecessary, but it     *
     * improves speed a little in a common case.                             */
    if (inlist)
	return;

    if (predisplaylen || postdisplaylen) {
	/* There is extra text to display at the start or end of the line */
	tmpline = zalloc(ll + predisplaylen + postdisplaylen);
	if (predisplaylen)
	    memcpy(tmpline, predisplay, predisplaylen);
	if (ll)
	    memcpy(tmpline+predisplaylen, line, ll);
	if (postdisplaylen)
	    memcpy(tmpline+predisplaylen+ll, postdisplay, postdisplaylen);
	tmpcs = cs + predisplaylen;
	tmpll = predisplaylen + ll + postdisplaylen;
	tmpalloced = 1;
    } else {
	tmpline = line;
	tmpcs = cs;
	tmpll = ll;
	tmpalloced = 0;
    }

    if (clearlist && listshown > 0) {
	if (tccan(TCCLEAREOD)) {
	    int ovln = vln, ovcs = vcs;
	    char *nb = nbuf[vln];

	    nbuf[vln] = obuf[vln];
	    moveto(nlnct, 0);
	    tcout(TCCLEAREOD);
	    moveto(ovln, ovcs);
	    nbuf[vln] = nb;
	} else {
	    invalidatelist();
	    moveto(0, 0);
	    clearflag = 0;
	    resetneeded = 1;
	}
	listshown = lastlistlen = 0;
	if (showinglist != -2)
	    showinglist = 0;
    }
    clearlist = 0;

#ifdef HAVE_SELECT
    cost = 0;			/* reset */
#endif

/* Nov 96: <mason>  I haven't checked how complete this is.  sgtty stuff may
   or may not work */
#if defined(SGTABTYPE)
    oxtabs = ((SGTTYFLAG & SGTABTYPE) == SGTABTYPE);
#else
    oxtabs = 0;
#endif

    cleareol = 0;		/* unset */
    more_start = more_end = 0;	/* unset */
    if (isset(SINGLELINEZLE) || lines < 3
	|| (termflags & (TERM_NOUP | TERM_BAD | TERM_UNKNOWN)))
	termflags |= TERM_SHORT;
    else
	termflags &= ~TERM_SHORT;
    if (resetneeded) {
	onumscrolls = 0;
	zsetterm();
#ifdef TIOCGWINSZ
	if (winchanged) {
	    moveto(0, 0);
	    t0 = olnct;		/* this is to clear extra lines even when */
	    winchanged = 0;	/* the terminal cannot TCCLEAREOD	  */
	    listshown = 0;
	}
#endif
	resetvideo();
	resetneeded = 0;	/* unset */
	oput_rpmpt = 0;		/* no right-prompt currently on screen */

	/* we probably should only have explicitly set attributes */
	tsetcap(TCALLATTRSOFF, 0);
	tsetcap(TCSTANDOUTEND, 0);
	tsetcap(TCUNDERLINEEND, 0);

        if (!clearflag) {
            if (tccan(TCCLEAREOD))
                tcout(TCCLEAREOD);
            else
                cleareol = 1;   /* request: clear to end of line */
	    if (listshown > 0)
		listshown = 0;
	}
        if (t0 > -1)
            olnct = (t0 < winh) ? t0 : winh;
        if (termflags & TERM_SHORT)
            vcs = 0;
        else if (!clearflag && lpromptbuf[0]) {
            zputs(lpromptbuf, shout);
	    if (lpromptwof == winw)
		zputs("\n", shout);	/* works with both hasam and !hasam */
	} else {
	    txtchange = pmpt_attr;
	    if (txtchangeisset(TXTNOBOLDFACE))
		tsetcap(TCALLATTRSOFF, 0);
	    if (txtchangeisset(TXTNOSTANDOUT))
		tsetcap(TCSTANDOUTEND, 0);
	    if (txtchangeisset(TXTNOUNDERLINE))
		tsetcap(TCUNDERLINEEND, 0);
	    if (txtchangeisset(TXTBOLDFACE))
		tsetcap(TCBOLDFACEBEG, 0);
	    if (txtchangeisset(TXTSTANDOUT))
		tsetcap(TCSTANDOUTBEG, 0);
	    if (txtchangeisset(TXTUNDERLINE))
		tsetcap(TCUNDERLINEBEG, 0);
	}
	if (clearflag) {
	    zputc('\r', shout);
	    vcs = 0;
	    moveto(0, lpromptw);
	}
	fflush(shout);
	clearf = clearflag;
    } else if (winw != columns || rwinh != lines)
	resetvideo();

/* now winw equals columns and winh equals lines 
   width comparisons can be made with winw, height comparisons with winh */

    if (termflags & TERM_SHORT) {
	singlerefresh(tmpline, tmpll, tmpcs);
	goto singlelineout;
    }

    if (tmpcs < 0) {
#ifdef DEBUG
	fprintf(stderr, "BUG: negative cursor position\n");
	fflush(stderr); 
#endif
	tmpcs = 0;
    }
    scs = tmpline + tmpcs;
    numscrolls = 0;

/* first, we generate the video line buffers so we know what to put on
   the screen - also determine final cursor position (nvln, nvcs) */

    /* Deemed necessary by PWS 1995/05/15 due to kill-line problems */
    if (!*nbuf)
	*nbuf = (char *)zalloc(winw + 2);

    s = (unsigned char *)(nbuf[ln = 0] + lpromptw);
    t = tmpline;
    sen = (unsigned char *)(*nbuf + winw);
    for (; t < tmpline+tmpll; t++) {
	if (t == scs)			/* if cursor is here, remember it */
	    nvcs = s - (unsigned char *)(nbuf[nvln = ln]);

	if (*t == '\n')	{		/* newline */
	    nbuf[ln][winw + 1] = '\0';	/* text not wrapped */
	    nextline
	} else if (*t == '\t') {		/* tab */
	    t0 = (char *)s - nbuf[ln];
	    if ((t0 | 7) + 1 >= winw) {
		nbuf[ln][winw + 1] = '\n';	/* text wrapped */
		nextline
	    } else
		do
		    *s++ = ' ';
		while ((++t0) & 7);
	} else if (icntrl(*t)) {	/* other control character */
	    *s++ = '^';
	    if (s == sen) {
		nbuf[ln][winw + 1] = '\n';	/* text wrapped */
		nextline
	    }
	    *s++ = (*t == 127) ? '?' : (*t | '@');
	} else				/* normal character */
	    *s++ = *t;
	if (s == sen) {
	    nbuf[ln][winw + 1] = '\n';	/* text wrapped */
	    nextline
	}
    }

/* if we're really on the next line, don't fake it; do everything properly */
    if (t == scs && (nvcs = s - (unsigned char *)(nbuf[nvln = ln])) == winw) {
	nbuf[ln][winw + 1] = '\n';	/* text wrapped */
	switch ('\0') { 	/* a sad hack to make the break */
	case '\0':		/* in nextline work */
	    nextline
	}
	*s = '\0';
	nvcs = 0;
	nvln++;
    }

    if (t != tmpline + tmpll)
	more_end = 1;

    if (statusline) {
	tosln = ln + 1;
	nbuf[ln][winw + 1] = '\0';	/* text not wrapped */
	snextline
	t = (unsigned char *)statusline;
	for (; t < (unsigned char *)statusline + statusll; t++) {
	    if (icntrl(*t)) {	/* simplified processing in the status line */
		*s++ = '^';
		if (s == sen) {
		    nbuf[ln][winw + 1] = '\n';	/* text wrapped */
		    snextline
		}
		*s++ = (*t == 127) ? '?' : (*t | '@');
	    } else
		*s++ = *t;
	    if (s == sen) {
		nbuf[ln][winw + 1] = '\n';	/* text wrapped */
		snextline
	    }
	}
	if (s == sen)
	    snextline
    }
    *s = '\0';

/* insert <.... at end of last line if there is more text past end of screen */
    if (more_end) {
	if (!statusline)
	    tosln = winh;
	s = nbuf[tosln - 1];
	sen = s + winw - 7;
	for (; s < sen; s++) {
	    if (*s == '\0') {
		for (; s < sen; )
		    *s++ = ' ';
		break;
	    }
	}
	strncpy(sen, " <.... ", 7);
	nbuf[tosln - 1][winw] = nbuf[tosln - 1][winw + 1] = '\0';
    }

/* insert <....> at end of first status line if status is too big */
    if (more_status) {
	s = nbuf[tosln];
	sen = s + winw - 8;
	for (; s < sen; s++) {
	    if (*s == '\0') {
		for (; s < sen; )
		    *s++ = ' ';
		break;
	    }
	}
	strncpy(sen, " <....> ", 8);
	nbuf[tosln][winw] = nbuf[tosln][winw + 1] = '\0';
    }

    nlnct = ln + 1;
    for (ln = nlnct; ln < winh; ln++)
	zfree(nbuf[ln], winw + 2), nbuf[ln] = NULL;

/* determine whether the right-prompt exists and can fit on the screen */
    if (!more_start) {
	if (trashedzle && opts[TRANSIENTRPROMPT])
	    put_rpmpt = 0;
	else
	    put_rpmpt = rprompth == 1 && rpromptbuf[0] &&
		!strchr(rpromptbuf, '\t') &&
		(int)strlen(nbuf[0]) + rpromptw < winw - 1;
    } else {
/* insert >.... on first line if there is more text before start of screen */
	memset(nbuf[0], ' ', lpromptw);
	t0 = winw - lpromptw;
	t0 = t0 > 5 ? 5 : t0;
	strncpy(nbuf[0] + lpromptw, ">....", t0);
	memset(nbuf[0] + lpromptw + t0, ' ', winw - t0 - lpromptw);
	nbuf[0][winw] = nbuf[0][winw + 1] = '\0';
    }

    for (ln = 0; ln < nlnct; ln++) {
	/* if we have more lines than last time, clear the newly-used lines */
	if (ln >= olnct)
	    cleareol = 1;

    /* if old line and new line are different,
       see if we can insert/delete a line to speed up update */

	if (!clearf && ln > 0 && ln < olnct - 1 && !(hasam && vcs == winw) &&
	    nbuf[ln] && obuf[ln] &&
	    strncmp(nbuf[ln], obuf[ln], 16)) {
	    if (tccan(TCDELLINE) && obuf[ln + 1] && obuf[ln + 1][0] &&
		nbuf[ln] && !strncmp(nbuf[ln], obuf[ln + 1], 16)) {
		moveto(ln, 0);
		tcout(TCDELLINE);
		zfree(obuf[ln], winw + 2);
		for (t0 = ln; t0 != olnct; t0++)
		    obuf[t0] = obuf[t0 + 1];
		obuf[--olnct] = NULL;
	    }
	/* don't try to insert a line if olnct = vmaxln (vmaxln is the number
	   of lines that have been displayed by this routine) so that we don't
	   go off the end of the screen. */

	    else if (tccan(TCINSLINE) && olnct < vmaxln && nbuf[ln + 1] &&
		     obuf[ln] && !strncmp(nbuf[ln + 1], obuf[ln], 16)) {
		moveto(ln, 0);
		tcout(TCINSLINE);
		for (t0 = olnct; t0 != ln; t0--)
		    obuf[t0] = obuf[t0 - 1];
		obuf[ln] = NULL;
		olnct++;
	    }
	}

    /* update the single line */
	refreshline(ln);

    /* output the right-prompt if appropriate */
	if (put_rpmpt && !ln && !oput_rpmpt) {
	    moveto(0, winw - 1 - rpromptw);
	    zputs(rpromptbuf, shout);
	    vcs = winw - 1;
	/* reset character attributes to that set by the main prompt */
	    txtchange = pmpt_attr;
	    if (txtchangeisset(TXTNOBOLDFACE) && (rpmpt_attr & TXTBOLDFACE))
		tsetcap(TCALLATTRSOFF, 0);
	    if (txtchangeisset(TXTNOSTANDOUT) && (rpmpt_attr & TXTSTANDOUT))
		tsetcap(TCSTANDOUTEND, 0);
	    if (txtchangeisset(TXTNOUNDERLINE) && (rpmpt_attr & TXTUNDERLINE))
		tsetcap(TCUNDERLINEEND, 0);
	    if (txtchangeisset(TXTBOLDFACE) && (rpmpt_attr & TXTNOBOLDFACE))
		tsetcap(TCBOLDFACEBEG, 0);
	    if (txtchangeisset(TXTSTANDOUT) && (rpmpt_attr & TXTNOSTANDOUT))
		tsetcap(TCSTANDOUTBEG, 0);
	    if (txtchangeisset(TXTUNDERLINE) && (rpmpt_attr & TXTNOUNDERLINE))
		tsetcap(TCUNDERLINEBEG, 0);
	}
    }

/* if old buffer had extra lines, set them to be cleared and refresh them
individually */

    if (olnct > nlnct) {
	cleareol = 1;
	for (ln = nlnct; ln < olnct; ln++)
	    refreshline(ln);
    }

/* reset character attributes */
    if (clearf && postedit) {
	if ((txtchange = pmpt_attr ? pmpt_attr : rpmpt_attr)) {
	    if (txtchangeisset(TXTNOBOLDFACE))
		tsetcap(TCALLATTRSOFF, 0);
	    if (txtchangeisset(TXTNOSTANDOUT))
		tsetcap(TCSTANDOUTEND, 0);
	    if (txtchangeisset(TXTNOUNDERLINE))
		tsetcap(TCUNDERLINEEND, 0);
	    if (txtchangeisset(TXTBOLDFACE))
		tsetcap(TCBOLDFACEBEG, 0);
	    if (txtchangeisset(TXTSTANDOUT))
		tsetcap(TCSTANDOUTBEG, 0);
	    if (txtchangeisset(TXTUNDERLINE))
		tsetcap(TCUNDERLINEBEG, 0);
	}
    }
    clearf = 0;
    oput_rpmpt = put_rpmpt;

/* move to the new cursor position */
    moveto(nvln, nvcs);

/* swap old and new buffers - better than freeing/allocating every time */
    qbuf = nbuf;
    nbuf = obuf;
    obuf = qbuf;
/* store current values so we can use them next time */
    ovln = nvln;
    olnct = nlnct;
    onumscrolls = numscrolls;
    if (nlnct > vmaxln)
	vmaxln = nlnct;
singlelineout:
    fflush(shout);		/* make sure everything is written out */

    if (tmpalloced)
	zfree(tmpline, tmpll);

    /* if we have a new list showing, note it; if part of the list has been
    overwritten, redisplay it. */
    if (showinglist == -2 || (showinglist > 0 && showinglist < nlnct)) {
	inlist = 1;
	listmatches();
	inlist = 0;
	zrefresh();
    }
    if (showinglist == -1)
	showinglist = nlnct;
}

#define tcinscost(X)   (tccan(TCMULTINS) ? tclen[TCMULTINS] : (X)*tclen[TCINS])
#define tcdelcost(X)   (tccan(TCMULTDEL) ? tclen[TCMULTDEL] : (X)*tclen[TCDEL])
#define tc_delchars(X)	(void) tcmultout(TCDEL, TCMULTDEL, (X))
#define tc_inschars(X)	(void) tcmultout(TCINS, TCMULTINS, (X))
#define tc_upcurs(X)	(void) tcmultout(TCUP, TCMULTUP, (X))
#define tc_leftcurs(X)	(void) tcmultout(TCLEFT, TCMULTLEFT, (X))

/* refresh one line, using whatever speed-up tricks are provided by the tty */

/**/
static void
refreshline(int ln)
{
    char *nl, *ol, *p1;		/* line buffer pointers			 */
    int ccs = 0,		/* temporary count for cursor position	 */
	char_ins = 0,		/* number of characters inserted/deleted */
	col_cleareol,		/* clear to end-of-line from this column */
	i, j,			/* tmp					 */
	ins_last,		/* insert pushed last character off line */
	nllen, ollen,		/* new and old line buffer lengths	 */
	rnllen;			/* real new line buffer length		 */

/* 0: setup */
    nl = nbuf[ln];
    rnllen = nllen = nl ? strlen(nl) : 0;
    ol = obuf[ln] ? obuf[ln] : "";
    ollen = strlen(ol);

/* optimisation: can easily happen for clearing old lines.  If the terminal has
   the capability, then this is the easiest way to skip unnecessary stuff */
    if (cleareol && !nllen && !(hasam && ln < nlnct - 1)
	&& tccan(TCCLEAREOL)) {
	moveto(ln, 0);
	tcout(TCCLEAREOL);
	return;	
    }

/* 1: pad out the new buffer with spaces to contain _all_ of the characters
      which need to be written. do this now to allow some pre-processing */

    if (cleareol 		/* request to clear to end of line */
	|| (!nllen && (ln != 0 || !put_rpmpt))	/* no line buffer given */
	|| (ln == 0 && (put_rpmpt != oput_rpmpt))) {	/* prompt changed */
	p1 = zhalloc(winw + 2);
	if (nllen)
	    strncpy(p1, nl, nllen);
	memset(p1 + nllen, ' ', winw - nllen);
	p1[winw] = '\0';
	p1[winw + 1] = (nllen < winw) ? '\0' : nl[winw + 1];
	if (ln && nbuf[ln])
	    memcpy(nl, p1, winw + 2);	/* next time obuf will be up-to-date */
	else
	    nl = p1;		/* don't keep the padding for prompt line */
	nllen = winw;
    } else if (ollen > nllen) { /* make new line at least as long as old */
	p1 = zhalloc(ollen + 1);
	strncpy(p1, nl, nllen);
	memset(p1 + nllen, ' ', ollen - nllen);
	p1[ollen] = '\0';
	nl = p1;
	nllen = ollen;
    }

/* 2: see if we can clear to end-of-line, and if it's faster, work out where
   to do it from - we can normally only do so if there's no right-prompt.
   With automatic margins, we shouldn't do it if there is another line, in
   case it messes up cut and paste. */

    if (hasam && ln < nlnct - 1 && rnllen == winw)
	col_cleareol = -2;	/* clearing eol would be evil so don't */
    else {
	col_cleareol = -1;
	if (tccan(TCCLEAREOL) && (nllen == winw || put_rpmpt != oput_rpmpt)) {
	    for (i = nllen; i && nl[i - 1] == ' '; i--);
	    for (j = ollen; j && ol[j - 1] == ' '; j--);
	    if ((j > i + tclen[TCCLEAREOL])	/* new buf has enough spaces */
		|| (nllen == winw && nl[winw - 1] == ' '))
		col_cleareol = i;
	}
    }

/* 2b: first a new trick for automargin niceness - good for cut and paste */

    if (hasam && vcs == winw) {
	if (nbuf[vln] && nbuf[vln][vcs + 1] == '\n') {
	    vln++, vcs = 1;
            if (nbuf[vln]  && *nbuf[vln])
		zputc(*nbuf[vln], shout);
	    else
		zputc(' ', shout);  /* I don't think this should happen */
	    if (ln == vln) {	/* better safe than sorry */
		nl++;
		if (*ol)
		    ol++;
		ccs = 1;
	    }			/* else  hmmm... I wonder what happened */
	} else {
	    vln++, vcs = 0;
	    zputc('\n', shout);
	}
    }
    ins_last = 0;

/* 2c: if we're on the first line, start checking at the end of the prompt;
   we shouldn't be doing anything within the prompt */

    if (ln == 0 && lpromptw) {
	i = lpromptw - ccs;
	j = strlen(ol);
	nl += i;
	ol += (i > j ? j : i);	/* if ol is too short, point it to '\0' */
	ccs = lpromptw;
    }

/* 3: main display loop - write out the buffer using whatever tricks we can */

    for (;;) {
	if (*nl && *ol && nl[1] == ol[1]) /* skip only if second chars match */
	/* skip past all matching characters */
	    for (; *nl && (*nl == *ol); nl++, ol++, ccs++) ;

	if (!*nl) {
	    if (ccs == winw && hasam && char_ins > 0 && ins_last
		&& vcs != winw) {
		nl--;           /* we can assume we can go back here */
		moveto(ln, winw - 1);
		zputc(*nl, shout);
		vcs++;
		return;         /* write last character in line */
	    }
	    if ((char_ins <= 0) || (ccs >= winw))    /* written everything */
		return;
	    if (tccan(TCCLEAREOL) && (char_ins >= tclen[TCCLEAREOL])
	    	&& col_cleareol != -2)
	    /* we've got junk on the right yet to clear */
		col_cleareol = 0;	/* force a clear to end of line */
	}

	moveto(ln, ccs);	/* move to where we do all output from */

    /* if we can finish quickly, do so */
	if ((col_cleareol >= 0) && (ccs >= col_cleareol)) {
	    tcout(TCCLEAREOL);
	    return;
	}

    /* we've written out the new but yet to clear rubbish due to inserts */
	if (!*nl) {
	    i = (winw - ccs < char_ins) ? (winw - ccs) : char_ins;
	    if (tccan(TCDEL) && (tcdelcost(i) <= i + 1))
		tc_delchars(i);
	    else {
		vcs += i;
		while (i-- > 0)
		    zputc(' ', shout);
	    }
	    return;
	}

    /* if we've reached the end of the old buffer, then there are few tricks
       we can do, so we just dump out what we must and clear if we can */
	if (!*ol) {
	    i = (col_cleareol >= 0) ? col_cleareol : nllen;
	    i -= vcs;
	    zwrite(nl, i, 1, shout);
	    vcs += i;
	    if (col_cleareol >= 0)
		tcout(TCCLEAREOL);
	    return;
	}

    /* inserting & deleting chars: we can if there's no right-prompt */
	if ((ln || !put_rpmpt || !oput_rpmpt) 
	    && (nl[1] && ol[1] && nl[1] != ol[1])) { 

	/* deleting characters - see if we can find a match series that
	   makes it cheaper to delete intermediate characters
	   eg. oldline: hifoobar \ hopefully cheaper here to delete two
	       newline: foobar	 / characters, then we have six matches */
	    if (tccan(TCDEL)) {
		for (i = 1; *(ol + i); i++)
		    if (tcdelcost(i) < pfxlen(ol + i, nl)) {
			tc_delchars(i);
			ol += i;
			char_ins -= i;
			i = 0;
			break;
		    }
		if (!i)
		    continue;
	    }
	/* inserting characters - characters pushed off the right should be
	   annihilated, but we don't do this if we're on the last line lest
	   undesired scrolling occurs due to `illegal' characters on screen */

	    if (tccan(TCINS) && (vln != lines - 1)) {	/* not on last line */
		for (i = 1; *(nl + i); i++)
		    if (tcinscost(i) < pfxlen(nl + i, ol)) {
			tc_inschars(i);
			zwrite(nl, i, 1, shout);
			nl += i;
			char_ins += i;
			ccs = (vcs += i);
		    /* if we've pushed off the right, truncate oldline */
			for (i = 0; *(ol + i) && i < winw - ccs; i++);
			if (i == winw - ccs) {
			    *(ol + i) = '\0';
			    ins_last = 1;
			}
			i = 0;
			break;
		    }
		if (!i)
		    continue;
	    }
	}
    /* we can't do any fancy tricks, so just dump the single character
       and keep on trying */
	zputc(*nl, shout);
	nl++, ol++;
	ccs++, vcs++;
    }
}

/* move the cursor to line ln (relative to the prompt line),
   absolute column cl; update vln, vcs - video line and column */

/**/
void
moveto(int ln, int cl)
{
    int c;

    if (vcs == winw) {
	vln++, vcs = 0;
	if (!hasam) {
	    zputc('\r', shout);
	    zputc('\n', shout);
	} else {
	    if ((vln < nlnct) && nbuf[vln] && *nbuf[vln])
		c = *nbuf[vln];
	    else
		c = ' ';
	    zputc(c, shout);
	    zputc('\r', shout);
	    if ((vln < olnct) && obuf[vln] && *obuf[vln])
		*obuf[vln] = c;
	}
    }

    if (ln == vln && cl == vcs)
	return;

/* move up */
    if (ln < vln) {
	tc_upcurs(vln - ln);
	vln = ln;
    }
/* move down; if we might go off the end of the screen, use newlines
   instead of TCDOWN */

    while (ln > vln) {
	if (vln < vmaxln - 1) {
	    if (ln > vmaxln - 1) {
		if (tc_downcurs(vmaxln - 1 - vln))
		    vcs = 0;
		vln = vmaxln - 1;
	    } else {
		if (tc_downcurs(ln - vln))
		    vcs = 0;
		vln = ln;
		continue;
	    }
	}
	zputc('\r', shout), vcs = 0; /* safety precaution */
	while (ln > vln) {
	    zputc('\n', shout);
	    vln++;
	}
    }

    if (cl != vcs)
        singmoveto(cl);
}

/**/
mod_export int
tcmultout(int cap, int multcap, int ct)
{
    if (tccan(multcap) && (!tccan(cap) || tclen[multcap] <= tclen[cap] * ct)) {
	tcoutarg(multcap, ct);
	return 1;
    } else if (tccan(cap)) {
	while (ct--)
	    tcout(cap);
	return 1;
    }
    return 0;
}

/* ct: number of characters to move across */
/**/
static void
tc_rightcurs(int ct)
{
    int cl,			/* ``desired'' absolute horizontal position */
	i = vcs,		/* cursor position after initial movements  */
	j;
    char *t;

    cl = ct + vcs;

/* do a multright if we can - it's the most reliable */
    if (tccan(TCMULTRIGHT)) {
	tcoutarg(TCMULTRIGHT, ct);
	return;
    }

/* do an absolute horizontal position if we can */
    if (tccan(TCHORIZPOS)) {
	tcoutarg(TCHORIZPOS, cl);
	return;
    }

/* XXX: should really check "it" in termcap and use / and % */
/* try tabs if tabs are non destructive and multright is not possible */
    if (!oxtabs && tccan(TCNEXTTAB) && ((vcs | 7) < cl)) {
	i = (vcs | 7) + 1;
	tcout(TCNEXTTAB);
	for ( ; i + 8 <= cl; i += 8)
	    tcout(TCNEXTTAB);
	if ((ct = cl - i) == 0) /* number of chars still to move across */
	    return;
    }

/* otherwise _carefully_ write the contents of the video buffer.
   if we're anywhere in the prompt, goto the left column and write the whole
   prompt out unless ztrlen(lpromptbuf) == lpromptw : we can cheat then */
    if (vln == 0 && i < lpromptw && !(termflags & TERM_SHORT)) {
	if (strlen(lpromptbuf) == lpromptw)
	    fputs(lpromptbuf + i, shout);
	else if (tccan(TCRIGHT) && (tclen[TCRIGHT] * ct <= ztrlen(lpromptbuf)))
	    /* it is cheaper to send TCRIGHT than reprint the whole prompt */
	    for (ct = lpromptw - i; ct--; )
		tcout(TCRIGHT);
        else {
	    if (i != 0)
		zputc('\r', shout);
	    tc_upcurs(lprompth - 1);
	    zputs(lpromptbuf, shout);
	    if (lpromptwof == winw)
		zputs("\n", shout);	/* works with both hasam and !hasam */
	}
	i = lpromptw;
	ct = cl - i;
    }

    if (nbuf[vln]) {
	for (j = 0, t = nbuf[vln]; *t && (j < i); j++, t++);
	if (j == i)
	    for ( ; *t && ct; ct--, t++)
		zputc(*t, shout);
    }
    while (ct--)
	zputc(' ', shout);	/* not my fault your terminal can't go right */
}

/**/
static int
tc_downcurs(int ct)
{
    int ret = 0;

    if (ct && !tcmultout(TCDOWN, TCMULTDOWN, ct)) {
	while (ct--)
	    zputc('\n', shout);
	zputc('\r', shout), ret = -1;
    }
    return ret;
}

/**/
mod_export void
tcout(int cap)
{
    tputs(tcstr[cap], 1, putshout);
    SELECT_ADD_COST(tclen[cap]);
}

/**/
static void
tcoutarg(int cap, int arg)
{
    char *result;

    result = tgoto(tcstr[cap], arg, arg);
    tputs(result, 1, putshout);
    SELECT_ADD_COST(strlen(result));
}

/**/
mod_export int
clearscreen(char **args)
{
    tcout(TCCLEARSCREEN);
    resetneeded = 1;
    clearflag = 0;
    return 0;
}

/**/
mod_export int
redisplay(char **args)
{
    moveto(0, 0);
    zputc('\r', shout);		/* extra care */
    tc_upcurs(lprompth - 1);
    resetneeded = 1;
    clearflag = 0;
    return 0;
}

/**/
static void
singlerefresh(unsigned char *tmpline, int tmpll, int tmpcs)
{
    char *vbuf, *vp,		/* video buffer and pointer    */
	**qbuf,			/* tmp			       */
	*refreshop = *obuf;	/* pointer to old video buffer */
    int t0,			/* tmp			       */
	vsiz,			/* size of new video buffer    */
	nvcs = 0;		/* new video cursor column     */

    nlnct = 1;
/* generate the new line buffer completely */
    for (vsiz = 1 + lpromptw, t0 = 0; t0 != tmpll; t0++, vsiz++)
	if (tmpline[t0] == '\t')
	    vsiz = (vsiz | 7) + 1;
	else if (icntrl(tmpline[t0]))
	    vsiz++;
    vbuf = (char *)zalloc(vsiz);

    if (tmpcs < 0) {
#ifdef DEBUG
	fprintf(stderr, "BUG: negative cursor position\n");
	fflush(stderr); 
#endif
	tmpcs = 0;
    }

    /* only use last part of prompt */
    memcpy(vbuf, strchr(lpromptbuf, 0) - lpromptw, lpromptw);
    vbuf[lpromptw] = '\0';
    vp = vbuf + lpromptw;

    for (t0 = 0; t0 != tmpll; t0++) {
	if (tmpline[t0] == '\t')
	    for (*vp++ = ' '; (vp - vbuf) & 7; )
		*vp++ = ' ';
	else if (tmpline[t0] == '\n') {
	    *vp++ = '\\';
	    *vp++ = 'n';
	} else if (tmpline[t0] == 0x7f) {
	    *vp++ = '^';
	    *vp++ = '?';
	} else if (icntrl(tmpline[t0])) {
	    *vp++ = '^';
	    *vp++ = tmpline[t0] | '@';
	} else
	    *vp++ = tmpline[t0];
	if (t0 == tmpcs)
	    nvcs = vp - vbuf - 1;
    }
    if (t0 == tmpcs)
	nvcs = vp - vbuf;
    *vp = '\0';

/* determine which part of the new line buffer we want for the display */
    if ((winpos && nvcs < winpos + 1) || (nvcs > winpos + winw - 2)) {
	if ((winpos = nvcs - ((winw - hasam) / 2)) < 0)
	    winpos = 0;
    }
    if (winpos)
	vbuf[winpos] = '<';	/* line continues to the left */
    if ((int)strlen(vbuf + winpos) > (winw - hasam)) {
	vbuf[winpos + winw - hasam - 1] = '>';	/* line continues to right */
	vbuf[winpos + winw - hasam] = '\0';
    }
    strcpy(nbuf[0], vbuf + winpos);
    zfree(vbuf, vsiz);
    nvcs -= winpos;

/* display the `visable' portion of the line buffer */
    for (t0 = 0, vp = *nbuf;;) {
    /* skip past all matching characters */
	for (; *vp && *vp == *refreshop; t0++, vp++, refreshop++) ;

	if (!*vp && !*refreshop)
	    break;

	singmoveto(t0);		/* move to where we do all output from */

	if (!*refreshop) {
	    if ((t0 = strlen(vp)))
		zwrite(vp, t0, 1, shout);
	    vcs += t0;
	    break;
	}
	if (!*vp) {
	    if (tccan(TCCLEAREOL))
		tcout(TCCLEAREOL);
	    else
		for (; *refreshop++; vcs++)
		    zputc(' ', shout);
	    break;
	}
	zputc(*vp, shout);
	vcs++, t0++;
	vp++, refreshop++;
    }
/* move to the new cursor position */
    singmoveto(nvcs);

    qbuf = nbuf;
    nbuf = obuf;
    obuf = qbuf;
}

/**/
static void
singmoveto(int pos)
{
    if (pos == vcs)
	return;

/* choose cheapest movements for ttys without multiple movement capabilities -
   do this now because it's easier (to code) */

    if ((!tccan(TCMULTLEFT) || pos == 0) && (pos <= vcs / 2)) {
	zputc('\r', shout);
	vcs = 0;
    }

    if (pos < vcs)
	tc_leftcurs(vcs - pos);
    else if (pos > vcs)
	tc_rightcurs(pos - vcs);

    vcs = pos;
}