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Add the source code for /usr/src/usr.bin from the Net/2 tape
[unix-history] / usr / src / usr.bin / window / wwupdate.c
/*
* Copyright (c) 1983 Regents of the University of California.
* All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Edward Wang at The University of California, Berkeley.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifndef lint
static char sccsid[] = "@(#)wwupdate.c 3.29 (Berkeley) 6/6/90";
#endif /* not lint */
#include "ww.h"
#include "tt.h"
wwupdate1(top, bot)
{
int i;
register j;
char *touched;
struct ww_update *upd;
char check_clreos = 0;
int scan_top, scan_bot;
wwnupdate++;
{
register char *t1 = wwtouched + top, *t2 = wwtouched + bot;
register n;
while (!*t1++)
if (t1 == t2)
return;
while (!*--t2)
;
scan_top = top = t1 - wwtouched - 1;
scan_bot = bot = t2 - wwtouched + 1;
if (scan_bot - scan_top > 1 &&
(tt.tt_clreos != 0 || tt.tt_clear != 0)) {
int st = tt.tt_clreos != 0 ? scan_top : 0;
/*
* t1 is one past the first touched row,
* t2 is on the last touched row.
*/
for (t1--, n = 1; t1 < t2;)
if (*t1++)
n++;
/*
* If we can't clreos then we try for clearing
* the whole screen.
*/
if (check_clreos = n * 10 > (wwnrow - st) * 9) {
scan_top = st;
scan_bot = wwnrow;
}
}
}
if (tt.tt_clreol == 0 && !check_clreos)
goto simple;
for (i = scan_top, touched = &wwtouched[i], upd = &wwupd[i];
i < scan_bot;
i++, touched++, upd++) {
register gain = 0;
register best_gain = 0;
register best_col;
register union ww_char *ns, *os;
if (wwinterrupt())
return;
if (!check_clreos && !*touched)
continue;
wwnupdscan++;
j = wwncol;
ns = &wwns[i][j];
os = &wwos[i][j];
while (--j >= 0) {
/*
* The cost of clearing is:
* ncol - nblank + X
* The cost of straight update is, more or less:
* ncol - nsame
* We clear if nblank - nsame > X
* X is the clreol overhead.
* So we make gain = nblank - nsame.
*/
if ((--ns)->c_w == (--os)->c_w)
gain--;
else
best_gain--;
if (ns->c_w == ' ')
gain++;
if (gain > best_gain) {
best_col = j;
best_gain = gain;
}
}
upd->best_gain = best_gain;
upd->best_col = best_col;
upd->gain = gain;
}
if (check_clreos) {
register struct ww_update *u;
register gain = 0;
register best_gain = 0;
int best_row;
register simple_gain = 0;
char didit = 0;
/*
* gain is the advantage of clearing all the lines.
* best_gain is the advantage of clearing to eos
* at best_row and u->best_col.
* simple_gain is the advantage of using only clreol.
* We use g > best_gain because u->best_col can be
* undefined when u->best_gain is 0 so we can't use it.
*/
for (j = scan_bot - 1, u = wwupd + j; j >= top; j--, u--) {
register g = gain + u->best_gain;
if (g > best_gain) {
best_gain = g;
best_row = j;
}
gain += u->gain;
if (tt.tt_clreol != 0 && u->best_gain > 4)
simple_gain += u->best_gain - 4;
}
if (tt.tt_clreos == 0) {
if (gain > simple_gain && gain > 4) {
xxclear();
i = top = scan_top;
bot = scan_bot;
j = 0;
didit = 1;
}
} else
if (best_gain > simple_gain && best_gain > 4) {
i = best_row;
xxclreos(i, j = wwupd[i].best_col);
bot = scan_bot;
didit = 1;
}
if (didit) {
wwnupdclreos++;
wwnupdclreosline += wwnrow - i;
u = wwupd + i;
while (i < scan_bot) {
register union ww_char *os = &wwos[i][j];
for (j = wwncol - j; --j >= 0;)
os++->c_w = ' ';
wwtouched[i++] |= WWU_TOUCHED;
u++->best_gain = 0;
j = 0;
}
} else
wwnupdclreosmiss++;
}
simple:
for (i = top, touched = &wwtouched[i], upd = &wwupd[i]; i < bot;
i++, touched++, upd++) {
register union ww_char *os, *ns;
char didit;
if (!*touched)
continue;
*touched = 0;
wwnupdline++;
didit = 0;
if (tt.tt_clreol != 0 && upd->best_gain > 4) {
wwnupdclreol++;
xxclreol(i, j = upd->best_col);
for (os = &wwos[i][j], j = wwncol - j; --j >= 0;)
os++->c_w = ' ';
didit = 1;
}
ns = wwns[i];
os = wwos[i];
for (j = 0; j < wwncol;) {
register char *p, *q;
char m;
int c;
register n;
char buf[512]; /* > wwncol */
union ww_char lastc;
for (; j++ < wwncol && ns++->c_w == os++->c_w;)
;
if (j > wwncol)
break;
p = buf;
m = ns[-1].c_m;
c = j - 1;
os[-1] = ns[-1];
*p++ = ns[-1].c_c;
n = 5;
q = p;
while (j < wwncol && ns->c_m == m) {
*p++ = ns->c_c;
if (ns->c_w == os->c_w) {
if (--n <= 0)
break;
os++;
ns++;
} else {
n = 5;
q = p;
lastc = *os;
*os++ = *ns++;
}
j++;
}
n = q - buf;
if (!wwwrap || i != wwnrow - 1 || c + n != wwncol)
xxwrite(i, c, buf, n, m);
else if (tt.tt_inschar || tt.tt_insspace) {
if (n > 1) {
q[-2] = q[-1];
n--;
} else
c--;
xxwrite(i, c, buf, n, m);
c += n - 1;
if (tt.tt_inschar)
xxinschar(i, c, ns[-2].c_c,
ns[-2].c_m);
else {
xxinsspace(i, c);
xxwrite(i, c, &ns[-2].c_c, 1,
ns[-2].c_m);
}
} else {
if (--n)
xxwrite(i, c, buf, n, m);
os[-1] = lastc;
*touched = WWU_TOUCHED;
}
didit = 1;
}
if (!didit)
wwnupdmiss++;
}
}
Continuous source code history from original PDP-7 UNIX to FreeBSD 2, the first fully unencumbered FreeBSD release.