2 * Copyright (c) 1989, 1993
3 * The Regents of the University of California. All rights reserved.
5 * This code is derived from software contributed to Berkeley by
6 * Edward Wang at The University of California, Berkeley.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by the University of
19 * California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
38 static char sccsid[] = "@(#)xxflush.c 8.1 (Berkeley) 6/6/93";
39 static char rcsid[] = "@(#)$FreeBSD$";
49 register struct xx *xp, *xq;
51 for (xp = xx_head; xp != 0 && !(intr && wwinterrupt()); xp = xq) {
55 (*tt.tt_move)(xp->arg0, xp->arg1);
61 (*tt.tt_move)(xp->arg0, xp->arg1);
62 tt.tt_nmodes = xp->arg3;
63 (*tt.tt_inschar)(xp->arg2);
66 (*tt.tt_move)(xp->arg0, xp->arg1);
67 (*tt.tt_insspace)(xp->arg2);
70 (*tt.tt_move)(xp->arg0, xp->arg1);
71 (*tt.tt_delchar)(xp->arg2);
77 (*tt.tt_move)(xp->arg0, xp->arg1);
81 (*tt.tt_move)(xp->arg0, xp->arg1);
85 (*tt.tt_move)(xp->arg0, xp->arg1);
86 tt.tt_nmodes = xp->arg3;
87 (*tt.tt_write)(xp->buf, xp->arg2);
93 if ((xx_head = xp) == 0) {
101 register struct xx *xp;
103 register struct xx *xq;
109 * We handle retain (da and db) by putting the burden on scrolling up,
110 * which is the less common operation. It must ensure that
111 * text is not pushed below the screen, so scrolling down doesn't
112 * have to worry about it.
114 * Try scrolling region (or scrolling the whole screen) first.
115 * Can we assume "sr" doesn't push text below the screen
116 * so we don't have to worry about retain below?
117 * What about scrolling down with a newline? It probably does
118 * push text above (with da). Scrolling up would then have
119 * to take care of that.
120 * It's easy to be fool proof, but that slows things down.
121 * The current solution is to disallow tt_scroll_up if da or db is true
122 * but cs (scrolling region) is not. Again, we sacrifice scrolling
123 * up in favor of scrolling down. The idea is having scrolling regions
124 * probably means we can scroll (even the whole screen) with impunity.
125 * This lets us work efficiently on simple terminals (use newline
126 * on the bottom to scroll), on any terminal without retain, and
127 * on vt100 style scrolling regions (I think).
130 if ((xq = xp->link) != 0 && xq->cmd == xc_scroll &&
131 xp->arg2 == xq->arg2 && xq->arg0 < 0) {
132 if (xp->arg1 < xq->arg1) {
133 if (xp->arg2 - xp->arg0 <= xq->arg1) {
139 xp->arg2 = xq->arg1 + xp->arg0;
140 xq->arg0 += xp->arg0;
143 xq->arg1 -= xq->arg0;
146 if (xp->arg1 - xq->arg0 >= xp->arg2)
148 xq->arg2 = xp->arg1 - xq->arg0;
149 xp->arg0 += xq->arg0;
152 xp->arg1 += xp->arg0;
156 if (xp->arg0 > xp->arg2 - xp->arg1)
157 xp->arg0 = xp->arg2 - xp->arg1;
158 if (tt.tt_scroll_down) {
159 if (tt.tt_scroll_top != xp->arg1 ||
160 tt.tt_scroll_bot != xp->arg2 - 1) {
161 if (tt.tt_setscroll == 0)
163 (*tt.tt_setscroll)(xp->arg1, xp->arg2 - 1);
165 tt.tt_scroll_down(xp->arg0);
168 (*tt.tt_move)(xp->arg1, 0);
169 (*tt.tt_delline)(xp->arg0);
170 if (xp->arg2 < tt.tt_nrow) {
171 (*tt.tt_move)(xp->arg2 - xp->arg0, 0);
172 (*tt.tt_insline)(xp->arg0);
176 xp->arg0 = - xp->arg0;
177 if (xp->arg0 > xp->arg2 - xp->arg1)
178 xp->arg0 = xp->arg2 - xp->arg1;
179 if (tt.tt_scroll_up) {
180 if (tt.tt_scroll_top != xp->arg1 ||
181 tt.tt_scroll_bot != xp->arg2 - 1) {
182 if (tt.tt_setscroll == 0)
184 (*tt.tt_setscroll)(xp->arg1, xp->arg2 - 1);
186 tt.tt_scroll_up(xp->arg0);
189 if (tt.tt_retain || xp->arg2 != tt.tt_nrow) {
190 (*tt.tt_move)(xp->arg2 - xp->arg0, 0);
191 (*tt.tt_delline)(xp->arg0);
193 (*tt.tt_move)(xp->arg1, 0);
194 (*tt.tt_insline)(xp->arg0);