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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 1.25 2004/12/11 18:28:51 tom Exp $")
49 _nc_scroll_window(WINDOW *win,
51 NCURSES_SIZE_T const top,
52 NCURSES_SIZE_T const bottom,
58 size_t to_copy = (size_t) (sizeof(NCURSES_CH_T) * (win->_maxx + 1));
60 TR(TRACE_MOVE, ("_nc_scroll_window(%p, %d, %d, %d)", win, n, top, bottom));
64 || bottom > win->_maxy) {
65 TR(TRACE_MOVE, ("nothing to scroll"));
70 * This used to do a line-text pointer-shuffle instead of text copies.
71 * That (a) doesn't work when the window is derived and doesn't have
72 * its own storage, (b) doesn't save you a lot on modern machines
73 * anyway. Your typical memcpy implementations are coded in
74 * assembler using a tight BLT loop; for the size of copies we're
75 * talking here, the total execution time is dominated by the one-time
76 * setup cost. So there is no point in trying to be excessively
80 /* shift n lines downwards */
83 for (line = bottom; line >= limit && line >= 0; line--) {
84 TR(TRACE_MOVE, ("...copying %d to %d", line + n, line));
85 memcpy(win->_line[line].text,
86 win->_line[line + n].text,
88 if_USE_SCROLL_HINTS(win->_line[line].oldindex =
89 win->_line[line + n].oldindex);
91 for (line = top; line < limit && line <= win->_maxy; line++) {
92 TR(TRACE_MOVE, ("...filling %d", line));
93 for (j = 0; j <= win->_maxx; j++)
94 win->_line[line].text[j] = blank;
95 if_USE_SCROLL_HINTS(win->_line[line].oldindex = _NEWINDEX);
99 /* shift n lines upwards */
102 for (line = top; line <= limit && line <= win->_maxy; line++) {
103 memcpy(win->_line[line].text,
104 win->_line[line + n].text,
106 if_USE_SCROLL_HINTS(win->_line[line].oldindex =
107 win->_line[line + n].oldindex);
109 for (line = bottom; line > limit && line >= 0; line--) {
110 for (j = 0; j <= win->_maxx; j++)
111 win->_line[line].text[j] = blank;
112 if_USE_SCROLL_HINTS(win->_line[line].oldindex = _NEWINDEX);
115 touchline(win, top, bottom - top + 1);
118 if (WINDOW_EXT(win, addch_used) != 0) {
119 int next = WINDOW_EXT(win, addch_y) + n;
120 if (next < 0 || next > win->_maxy) {
122 ("Alert discarded multibyte on scroll"));
123 WINDOW_EXT(win, addch_y) = 0;
125 TR(TRACE_VIRTPUT, ("scrolled working position to %d,%d",
126 WINDOW_EXT(win, addch_y),
127 WINDOW_EXT(win, addch_x)));
128 WINDOW_EXT(win, addch_y) = next;
135 wscrl(WINDOW *win, int n)
137 T((T_CALLED("wscrl(%p,%d)"), win, n));
139 if (!win || !win->_scroll) {
140 TR(TRACE_MOVE, ("...scrollok is false"));
145 _nc_scroll_window(win, n, win->_regtop, win->_regbottom, win->_nc_bkgd);