1 /****************************************************************************
2 * Copyright (c) 1998-2011,2019 Free Software Foundation, Inc. *
4 * Permission is hereby granted, free of charge, to any person obtaining a *
5 * copy of this software and associated documentation files (the *
6 * "Software"), to deal in the Software without restriction, including *
7 * without limitation the rights to use, copy, modify, merge, publish, *
8 * distribute, distribute with modifications, sublicense, and/or sell *
9 * copies of the Software, and to permit persons to whom the Software is *
10 * furnished to do so, subject to the following conditions: *
12 * The above copyright notice and this permission notice shall be included *
13 * in all copies or substantial portions of the Software. *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS *
16 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF *
17 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. *
18 * IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, *
19 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR *
20 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR *
21 * THE USE OR OTHER DEALINGS IN THE SOFTWARE. *
23 * Except as contained in this notice, the name(s) of the above copyright *
24 * holders shall not be used in advertising or otherwise to promote the *
25 * sale, use or other dealings in this Software without prior written *
27 ****************************************************************************/
29 /****************************************************************************
30 * Author: Thomas E. Dickey 1996-2003 *
31 * and: Zeyd M. Ben-Halim <zmbenhal@netcom.com> 1992,1995 *
32 * and: Eric S. Raymond <esr@snark.thyrsus.com> *
33 ****************************************************************************/
38 ** The routine wscrl(win, n).
39 ** positive n scroll the window up (ie. move lines down)
40 ** negative n scroll the window down (ie. move lines up)
44 #include <curses.priv.h>
46 MODULE_ID("$Id: lib_scroll.c,v 1.31 2019/08/03 22:27:55 tom Exp $")
49 _nc_scroll_window(WINDOW *win,
58 size_t to_copy = (sizeof(NCURSES_CH_T) * (size_t) (win->_maxx + 1));
60 TR(TRACE_MOVE, ("_nc_scroll_window(%p, %d, %ld, %ld)",
61 (void *) win, n, (long) top, (long) bottom));
65 || bottom > win->_maxy) {
66 TR(TRACE_MOVE, ("nothing to scroll"));
71 * This used to do a line-text pointer-shuffle instead of text copies.
72 * That (a) doesn't work when the window is derived and doesn't have
73 * its own storage, (b) doesn't save you a lot on modern machines
74 * anyway. Your typical memcpy implementations are coded in
75 * assembler using a tight BLT loop; for the size of copies we're
76 * talking here, the total execution time is dominated by the one-time
77 * setup cost. So there is no point in trying to be excessively
80 #define BottomLimit(n) ((n) >= 0 && (n) >= top)
81 #define TopLimit(n) ((n) <= win->_maxy && (n) <= bottom)
83 /* shift n lines downwards */
86 for (line = bottom; line >= limit && BottomLimit(line); line--) {
87 TR(TRACE_MOVE, ("...copying %d to %d", line + n, line));
88 memcpy(win->_line[line].text,
89 win->_line[line + n].text,
91 if_USE_SCROLL_HINTS(win->_line[line].oldindex =
92 win->_line[line + n].oldindex);
94 for (line = top; line < limit && TopLimit(line); line++) {
95 TR(TRACE_MOVE, ("...filling %d", line));
96 for (j = 0; j <= win->_maxx; j++)
97 win->_line[line].text[j] = blank;
98 if_USE_SCROLL_HINTS(win->_line[line].oldindex = _NEWINDEX);
102 /* shift n lines upwards */
105 for (line = top; line <= limit && TopLimit(line); line++) {
106 memcpy(win->_line[line].text,
107 win->_line[line + n].text,
109 if_USE_SCROLL_HINTS(win->_line[line].oldindex =
110 win->_line[line + n].oldindex);
112 for (line = bottom; line > limit && BottomLimit(line); line--) {
113 for (j = 0; j <= win->_maxx; j++)
114 win->_line[line].text[j] = blank;
115 if_USE_SCROLL_HINTS(win->_line[line].oldindex = _NEWINDEX);
118 touchline(win, top, bottom - top + 1);
121 if (WINDOW_EXT(win, addch_used) != 0) {
122 int next = WINDOW_EXT(win, addch_y) + n;
123 if (next < 0 || next > win->_maxy) {
125 ("Alert discarded multibyte on scroll"));
126 WINDOW_EXT(win, addch_y) = 0;
128 TR(TRACE_VIRTPUT, ("scrolled working position to %d,%d",
129 WINDOW_EXT(win, addch_y),
130 WINDOW_EXT(win, addch_x)));
131 WINDOW_EXT(win, addch_y) = next;
138 wscrl(WINDOW *win, int n)
140 T((T_CALLED("wscrl(%p,%d)"), (void *) win, n));
142 if (!win || !win->_scroll) {
143 TR(TRACE_MOVE, ("...scrollok is false"));
148 _nc_scroll_window(win, n, win->_regtop, win->_regbottom, win->_nc_bkgd);