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29 /****************************************************************************
30 * Author: Zeyd M. Ben-Halim <zmbenhal@netcom.com> 1992,1995 *
31 * and: Eric S. Raymond <esr@snark.thyrsus.com> *
32 ****************************************************************************/
37 ** The routine wscrl(win, n).
38 ** positive n scroll the window up (ie. move lines down)
39 ** negative n scroll the window down (ie. move lines up)
43 #include <curses.priv.h>
45 MODULE_ID("$Id: lib_scroll.c,v 1.17 2000/04/29 21:10:51 tom Exp $")
48 _nc_scroll_window(WINDOW *win, int const n, NCURSES_SIZE_T const top,
49 NCURSES_SIZE_T const bottom, chtype blank)
52 size_t to_copy = (size_t) (sizeof(chtype) * (win->_maxx + 1));
54 TR(TRACE_MOVE, ("_nc_scroll_window(%p, %d, %d, %d)", win, n, top, bottom));
57 * This used to do a line-text pointer-shuffle instead of text copies.
58 * That (a) doesn't work when the window is derived and doesn't have
59 * its own storage, (b) doesn't save you a lot on modern machines
60 * anyway. Your typical memcpy implementations are coded in
61 * assembler using a tight BLT loop; for the size of copies we're
62 * talking here, the total execution time is dominated by the one-time
63 * setup cost. So there is no point in trying to be excessively
67 /* shift n lines downwards */
69 for (line = bottom; line >= top - n; line--) {
70 memcpy(win->_line[line].text,
71 win->_line[line + n].text,
73 if_USE_SCROLL_HINTS(win->_line[line].oldindex = win->_line[line
76 for (line = top; line < top - n; line++) {
77 for (j = 0; j <= win->_maxx; j++)
78 win->_line[line].text[j] = blank;
79 if_USE_SCROLL_HINTS(win->_line[line].oldindex = _NEWINDEX);
83 /* shift n lines upwards */
85 for (line = top; line <= bottom - n; line++) {
86 memcpy(win->_line[line].text,
87 win->_line[line + n].text,
89 if_USE_SCROLL_HINTS(win->_line[line].oldindex = win->_line[line
92 for (line = bottom; line > bottom - n; 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);
98 touchline(win, top, bottom - top + 1);
102 wscrl(WINDOW *win, int n)
104 T((T_CALLED("wscrl(%p,%d)"), win, n));
106 if (!win || !win->_scroll)
112 if ((n > (win->_regbottom - win->_regtop)) ||
113 (-n > (win->_regbottom - win->_regtop)))
116 _nc_scroll_window(win, n, win->_regtop, win->_regbottom, _nc_background(win));