1 /*	$OpenBSD: xxflush.c,v 1.5 2003/06/03 02:56:24 millert Exp $	*/
2 /*	$NetBSD: xxflush.c,v 1.3 1995/09/28 10:36:05 tls Exp $	*/
3 
4 /*
5  * Copyright (c) 1989, 1993
6  *	The Regents of the University of California.  All rights reserved.
7  *
8  * This code is derived from software contributed to Berkeley by
9  * Edward Wang at The University of California, Berkeley.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  * 3. Neither the name of the University nor the names of its contributors
20  *    may be used to endorse or promote products derived from this software
21  *    without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  */
35 
36 #ifndef lint
37 #if 0
38 static char sccsid[] = "@(#)xxflush.c	8.1 (Berkeley) 6/6/93";
39 #else
40 static char rcsid[] = "$OpenBSD: xxflush.c,v 1.5 2003/06/03 02:56:24 millert Exp $";
41 #endif
42 #endif /* not lint */
43 
44 #include "ww.h"
45 #include "xx.h"
46 #include "tt.h"
47 
xxflush(intr)48 xxflush(intr)
49 	int intr;
50 {
51 	struct xx *xp, *xq;
52 
53 	for (xp = xx_head; xp != 0 && !(intr && wwinterrupt()); xp = xq) {
54 		switch (xp->cmd) {
55 		case xc_move:
56 			if (xp->link == 0)
57 				(*tt.tt_move)(xp->arg0, xp->arg1);
58 			break;
59 		case xc_scroll:
60 			xxflush_scroll(xp);
61 			break;
62 		case xc_inschar:
63 			(*tt.tt_move)(xp->arg0, xp->arg1);
64 			tt.tt_nmodes = xp->arg3;
65 			(*tt.tt_inschar)(xp->arg2);
66 			break;
67 		case xc_insspace:
68 			(*tt.tt_move)(xp->arg0, xp->arg1);
69 			(*tt.tt_insspace)(xp->arg2);
70 			break;
71 		case xc_delchar:
72 			(*tt.tt_move)(xp->arg0, xp->arg1);
73 			(*tt.tt_delchar)(xp->arg2);
74 			break;
75 		case xc_clear:
76 			(*tt.tt_clear)();
77 			break;
78 		case xc_clreos:
79 			(*tt.tt_move)(xp->arg0, xp->arg1);
80 			(*tt.tt_clreos)();
81 			break;
82 		case xc_clreol:
83 			(*tt.tt_move)(xp->arg0, xp->arg1);
84 			(*tt.tt_clreol)();
85 			break;
86 		case xc_write:
87 			(*tt.tt_move)(xp->arg0, xp->arg1);
88 			tt.tt_nmodes = xp->arg3;
89 			(*tt.tt_write)(xp->buf, xp->arg2);
90 			break;
91 		}
92 		xq = xp->link;
93 		xxfree(xp);
94 	}
95 	if ((xx_head = xp) == 0) {
96 		xx_tail = 0;
97 		xxbufp = xxbuf;
98 	}
99 	ttflush();
100 }
101 
102 xxflush_scroll(xp)
103 	struct xx *xp;
104 {
105 	struct xx *xq;
106 
107  top:
108 	if (xp->arg0 == 0)
109 		return;
110 	/*
111 	 * We handle retain (da and db) by putting the burden on scrolling up,
112 	 * which is the less common operation.  It must ensure that
113 	 * text is not pushed below the screen, so scrolling down doesn't
114 	 * have to worry about it.
115 	 *
116 	 * Try scrolling region (or scrolling the whole screen) first.
117 	 * Can we assume "sr" doesn't push text below the screen
118 	 * so we don't have to worry about retain below?
119 	 * What about scrolling down with a newline?  It probably does
120 	 * push text above (with da).  Scrolling up would then have
121 	 * to take care of that.
122 	 * It's easy to be fool proof, but that slows things down.
123 	 * The current solution is to disallow tt_scroll_up if da or db is true
124 	 * but cs (scrolling region) is not.  Again, we sacrifice scrolling
125 	 * up in favor of scrolling down.  The idea is having scrolling regions
126 	 * probably means we can scroll (even the whole screen) with impunity.
127 	 * This lets us work efficiently on simple terminals (use newline
128 	 * on the bottom to scroll), on any terminal without retain, and
129 	 * on vt100 style scrolling regions (I think).
130 	 */
131 	if (xp->arg0 > 0) {
132 		if ((xq = xp->link) != 0 && xq->cmd == xc_scroll &&
133 		    xp->arg2 == xq->arg2 && xq->arg0 < 0) {
134 			if (xp->arg1 < xq->arg1) {
135 				if (xp->arg2 - xp->arg0 <= xq->arg1) {
136 					xq->arg0 = xp->arg0;
137 					xq->arg1 = xp->arg1;
138 					xq->arg2 = xp->arg2;
139 					return;
140 				}
141 				xp->arg2 = xq->arg1 + xp->arg0;
142 				xq->arg0 += xp->arg0;
143 				xq->arg1 = xp->arg2;
144 				if (xq->arg0 > 0)
145 					xq->arg1 -= xq->arg0;
146 				goto top;
147 			} else {
148 				if (xp->arg1 - xq->arg0 >= xp->arg2)
149 					return;
150 				xq->arg2 = xp->arg1 - xq->arg0;
151 				xp->arg0 += xq->arg0;
152 				xp->arg1 = xq->arg2;
153 				if (xp->arg0 < 0)
154 					xp->arg1 += xp->arg0;
155 				goto top;
156 			}
157 		}
158 		if (xp->arg0 > xp->arg2 - xp->arg1)
159 			xp->arg0 = xp->arg2 - xp->arg1;
160 		if (tt.tt_scroll_down) {
161 			if (tt.tt_scroll_top != xp->arg1 ||
162 			    tt.tt_scroll_bot != xp->arg2 - 1) {
163 				if (tt.tt_setscroll == 0)
164 					goto down;
165 				(*tt.tt_setscroll)(xp->arg1, xp->arg2 - 1);
166 			}
167 			tt.tt_scroll_down(xp->arg0);
168 		} else {
169 		down:
170 			(*tt.tt_move)(xp->arg1, 0);
171 			(*tt.tt_delline)(xp->arg0);
172 			if (xp->arg2 < tt.tt_nrow) {
173 				(*tt.tt_move)(xp->arg2 - xp->arg0, 0);
174 				(*tt.tt_insline)(xp->arg0);
175 			}
176 		}
177 	} else {
178 		xp->arg0 = - xp->arg0;
179 		if (xp->arg0 > xp->arg2 - xp->arg1)
180 			xp->arg0 = xp->arg2 - xp->arg1;
181 		if (tt.tt_scroll_up) {
182 			if (tt.tt_scroll_top != xp->arg1 ||
183 			    tt.tt_scroll_bot != xp->arg2 - 1) {
184 				if (tt.tt_setscroll == 0)
185 					goto up;
186 				(*tt.tt_setscroll)(xp->arg1, xp->arg2 - 1);
187 			}
188 			tt.tt_scroll_up(xp->arg0);
189 		} else  {
190 		up:
191 			if (tt.tt_retain || xp->arg2 != tt.tt_nrow) {
192 				(*tt.tt_move)(xp->arg2 - xp->arg0, 0);
193 				(*tt.tt_delline)(xp->arg0);
194 			}
195 			(*tt.tt_move)(xp->arg1, 0);
196 			(*tt.tt_insline)(xp->arg0);
197 		}
198 	}
199 }
200