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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 1.29 2011/10/22 16:34:50 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
81 /* shift n lines downwards */
84 for (line = bottom; line >= limit && line >= 0; line--) {
85 TR(TRACE_MOVE, ("...copying %d to %d", line + n, line));
86 memcpy(win->_line[line].text,
87 win->_line[line + n].text,
89 if_USE_SCROLL_HINTS(win->_line[line].oldindex =
90 win->_line[line + n].oldindex);
92 for (line = top; line < limit && line <= win->_maxy; line++) {
93 TR(TRACE_MOVE, ("...filling %d", line));
94 for (j = 0; j <= win->_maxx; j++)
95 win->_line[line].text[j] = blank;
96 if_USE_SCROLL_HINTS(win->_line[line].oldindex = _NEWINDEX);
100 /* shift n lines upwards */
103 for (line = top; line <= limit && line <= win->_maxy; line++) {
104 memcpy(win->_line[line].text,
105 win->_line[line + n].text,
107 if_USE_SCROLL_HINTS(win->_line[line].oldindex =
108 win->_line[line + n].oldindex);
110 for (line = bottom; line > limit && line >= 0; line--) {
111 for (j = 0; j <= win->_maxx; j++)
112 win->_line[line].text[j] = blank;
113 if_USE_SCROLL_HINTS(win->_line[line].oldindex = _NEWINDEX);
116 touchline(win, top, bottom - top + 1);
119 if (WINDOW_EXT(win, addch_used) != 0) {
120 int next = WINDOW_EXT(win, addch_y) + n;
121 if (next < 0 || next > win->_maxy) {
123 ("Alert discarded multibyte on scroll"));
124 WINDOW_EXT(win, addch_y) = 0;
126 TR(TRACE_VIRTPUT, ("scrolled working position to %d,%d",
127 WINDOW_EXT(win, addch_y),
128 WINDOW_EXT(win, addch_x)));
129 WINDOW_EXT(win, addch_y) = next;
136 wscrl(WINDOW *win, int n)
138 T((T_CALLED("wscrl(%p,%d)"), (void *) win, n));
140 if (!win || !win->_scroll) {
141 TR(TRACE_MOVE, ("...scrollok is false"));
146 _nc_scroll_window(win, n, win->_regtop, win->_regbottom, win->_nc_bkgd);