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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 1.24 2003/07/26 23:25:26 tom Exp $")
49 _nc_scroll_window(WINDOW *win, int const n, NCURSES_SIZE_T const top,
50 NCURSES_SIZE_T const bottom, NCURSES_CH_T blank)
55 size_t to_copy = (size_t) (sizeof(NCURSES_CH_T) * (win->_maxx + 1));
57 TR(TRACE_MOVE, ("_nc_scroll_window(%p, %d, %d, %d)", win, n, top, bottom));
61 || bottom > win->_maxy) {
62 TR(TRACE_MOVE, ("nothing to scroll"));
67 * This used to do a line-text pointer-shuffle instead of text copies.
68 * That (a) doesn't work when the window is derived and doesn't have
69 * its own storage, (b) doesn't save you a lot on modern machines
70 * anyway. Your typical memcpy implementations are coded in
71 * assembler using a tight BLT loop; for the size of copies we're
72 * talking here, the total execution time is dominated by the one-time
73 * setup cost. So there is no point in trying to be excessively
77 /* shift n lines downwards */
80 for (line = bottom; line >= limit && line >= 0; line--) {
81 TR(TRACE_MOVE, ("...copying %d to %d", line + n, line));
82 memcpy(win->_line[line].text,
83 win->_line[line + n].text,
85 if_USE_SCROLL_HINTS(win->_line[line].oldindex =
86 win->_line[line + n].oldindex);
88 for (line = top; line < limit && line <= win->_maxy; line++) {
89 TR(TRACE_MOVE, ("...filling %d", line));
90 for (j = 0; j <= win->_maxx; j++)
91 win->_line[line].text[j] = blank;
92 if_USE_SCROLL_HINTS(win->_line[line].oldindex = _NEWINDEX);
96 /* shift n lines upwards */
99 for (line = top; line <= limit && line <= win->_maxy; line++) {
100 memcpy(win->_line[line].text,
101 win->_line[line + n].text,
103 if_USE_SCROLL_HINTS(win->_line[line].oldindex =
104 win->_line[line + n].oldindex);
106 for (line = bottom; line > limit && line >= 0; line--) {
107 for (j = 0; j <= win->_maxx; j++)
108 win->_line[line].text[j] = blank;
109 if_USE_SCROLL_HINTS(win->_line[line].oldindex = _NEWINDEX);
112 touchline(win, top, bottom - top + 1);
116 wscrl(WINDOW *win, int n)
118 T((T_CALLED("wscrl(%p,%d)"), win, n));
120 if (!win || !win->_scroll) {
121 TR(TRACE_MOVE, ("...scrollok is false"));
126 _nc_scroll_window(win, n, win->_regtop, win->_regbottom, win->_nc_bkgd);