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
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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";
48 register struct xx *xp, *xq;
50 for (xp = xx_head; xp != 0 && !(intr && wwinterrupt()); xp = xq) {
54 (*tt.tt_move)(xp->arg0, xp->arg1);
60 (*tt.tt_move)(xp->arg0, xp->arg1);
61 tt.tt_nmodes = xp->arg3;
62 (*tt.tt_inschar)(xp->arg2);
65 (*tt.tt_move)(xp->arg0, xp->arg1);
66 (*tt.tt_insspace)(xp->arg2);
69 (*tt.tt_move)(xp->arg0, xp->arg1);
70 (*tt.tt_delchar)(xp->arg2);
76 (*tt.tt_move)(xp->arg0, xp->arg1);
80 (*tt.tt_move)(xp->arg0, xp->arg1);
84 (*tt.tt_move)(xp->arg0, xp->arg1);
85 tt.tt_nmodes = xp->arg3;
86 (*tt.tt_write)(xp->buf, xp->arg2);
92 if ((xx_head = xp) == 0) {
100 register struct xx *xp;
102 register struct xx *xq;
108 * We handle retain (da and db) by putting the burden on scrolling up,
109 * which is the less common operation. It must ensure that
110 * text is not pushed below the screen, so scrolling down doesn't
111 * have to worry about it.
113 * Try scrolling region (or scrolling the whole screen) first.
114 * Can we assume "sr" doesn't push text below the screen
115 * so we don't have to worry about retain below?
116 * What about scrolling down with a newline? It probably does
117 * push text above (with da). Scrolling up would then have
118 * to take care of that.
119 * It's easy to be fool proof, but that slows things down.
120 * The current solution is to disallow tt_scroll_up if da or db is true
121 * but cs (scrolling region) is not. Again, we sacrifice scrolling
122 * up in favor of scrolling down. The idea is having scrolling regions
123 * probably means we can scroll (even the whole screen) with impunity.
124 * This lets us work efficiently on simple terminals (use newline
125 * on the bottom to scroll), on any terminal without retain, and
126 * on vt100 style scrolling regions (I think).
129 if ((xq = xp->link) != 0 && xq->cmd == xc_scroll &&
130 xp->arg2 == xq->arg2 && xq->arg0 < 0) {
131 if (xp->arg1 < xq->arg1) {
132 if (xp->arg2 - xp->arg0 <= xq->arg1) {
138 xp->arg2 = xq->arg1 + xp->arg0;
139 xq->arg0 += xp->arg0;
142 xq->arg1 -= xq->arg0;
145 if (xp->arg1 - xq->arg0 >= xp->arg2)
147 xq->arg2 = xp->arg1 - xq->arg0;
148 xp->arg0 += xq->arg0;
151 xp->arg1 += xp->arg0;
155 if (xp->arg0 > xp->arg2 - xp->arg1)
156 xp->arg0 = xp->arg2 - xp->arg1;
157 if (tt.tt_scroll_down) {
158 if (tt.tt_scroll_top != xp->arg1 ||
159 tt.tt_scroll_bot != xp->arg2 - 1) {
160 if (tt.tt_setscroll == 0)
162 (*tt.tt_setscroll)(xp->arg1, xp->arg2 - 1);
164 tt.tt_scroll_down(xp->arg0);
167 (*tt.tt_move)(xp->arg1, 0);
168 (*tt.tt_delline)(xp->arg0);
169 if (xp->arg2 < tt.tt_nrow) {
170 (*tt.tt_move)(xp->arg2 - xp->arg0, 0);
171 (*tt.tt_insline)(xp->arg0);
175 xp->arg0 = - xp->arg0;
176 if (xp->arg0 > xp->arg2 - xp->arg1)
177 xp->arg0 = xp->arg2 - xp->arg1;
178 if (tt.tt_scroll_up) {
179 if (tt.tt_scroll_top != xp->arg1 ||
180 tt.tt_scroll_bot != xp->arg2 - 1) {
181 if (tt.tt_setscroll == 0)
183 (*tt.tt_setscroll)(xp->arg1, xp->arg2 - 1);
185 tt.tt_scroll_up(xp->arg0);
188 if (tt.tt_retain || xp->arg2 != tt.tt_nrow) {
189 (*tt.tt_move)(xp->arg2 - xp->arg0, 0);
190 (*tt.tt_delline)(xp->arg0);
192 (*tt.tt_move)(xp->arg1, 0);
193 (*tt.tt_insline)(xp->arg0);