ncurses 5.0

[ncurses.git] / ncurses / base / lib_scroll.c

diff --git a/ncurses/base/lib_scroll.c b/ncurses/base/lib_scroll.c
new file mode 100644 (file)
index 0000000..197bb22
--- /dev/null
+++ b/ncurses/base/lib_scroll.c
@@ -0,0 +1,118 @@
+/****************************************************************************
+ * Copyright (c) 1998 Free Software Foundation, Inc.                        *
+ *                                                                          *
+ * Permission is hereby granted, free of charge, to any person obtaining a  *
+ * copy of this software and associated documentation files (the            *
+ * "Software"), to deal in the Software without restriction, including      *
+ * without limitation the rights to use, copy, modify, merge, publish,      *
+ * distribute, distribute with modifications, sublicense, and/or sell       *
+ * copies of the Software, and to permit persons to whom the Software is    *
+ * furnished to do so, subject to the following conditions:                 *
+ *                                                                          *
+ * The above copyright notice and this permission notice shall be included  *
+ * in all copies or substantial portions of the Software.                   *
+ *                                                                          *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS  *
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF               *
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.   *
+ * IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,   *
+ * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR    *
+ * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR    *
+ * THE USE OR OTHER DEALINGS IN THE SOFTWARE.                               *
+ *                                                                          *
+ * Except as contained in this notice, the name(s) of the above copyright   *
+ * holders shall not be used in advertising or otherwise to promote the     *
+ * sale, use or other dealings in this Software without prior written       *
+ * authorization.                                                           *
+ ****************************************************************************/
+
+/****************************************************************************
+ *  Author: Zeyd M. Ben-Halim <zmbenhal@netcom.com> 1992,1995               *
+ *     and: Eric S. Raymond <esr@snark.thyrsus.com>                         *
+ ****************************************************************************/
+
+
+
+/*
+**     lib_scroll.c
+**
+**     The routine wscrl(win, n).
+**  positive n scroll the window up (ie. move lines down)
+**  negative n scroll the window down (ie. move lines up)
+**
+*/
+
+#include <curses.priv.h>
+
+MODULE_ID("$Id: lib_scroll.c,v 1.16 1998/02/11 12:13:55 tom Exp $")
+
+void _nc_scroll_window(WINDOW *win, int const n, short const top, short const bottom, chtype blank)
+{
+int    line, j;
+size_t to_copy = (size_t)(sizeof(chtype) * (win->_maxx + 1));
+
+       TR(TRACE_MOVE, ("_nc_scroll_window(%p, %d, %d, %d)", win, n, top,bottom)); 
+
+       /*
+        * This used to do a line-text pointer-shuffle instead of text copies.
+        * That (a) doesn't work when the window is derived and doesn't have
+        * its own storage, (b) doesn't save you a lot on modern machines
+        * anyway.  Your typical memcpy implementations are coded in
+        * assembler using a tight BLT loop; for the size of copies we're
+        * talking here, the total execution time is dominated by the one-time
+        * setup cost.  So there is no point in trying to be excessively
+        * clever -- esr.
+        */
+
+       /* shift n lines downwards */
+       if (n < 0) {
+               for (line = bottom; line >= top-n; line--) {
+                       memcpy(win->_line[line].text,
+                              win->_line[line+n].text,
+                              to_copy);
+                       if_USE_SCROLL_HINTS(win->_line[line].oldindex = win->_line[line+n].oldindex);
+               }
+               for (line = top; line < top-n; line++) {
+                       for (j = 0; j <= win->_maxx; j ++)
+                               win->_line[line].text[j] = blank;
+                       if_USE_SCROLL_HINTS(win->_line[line].oldindex = _NEWINDEX);
+               }
+       }
+
+       /* shift n lines upwards */
+       if (n > 0) {
+               for (line = top; line <= bottom-n; line++) {
+                       memcpy(win->_line[line].text,
+                              win->_line[line+n].text,
+                              to_copy);
+                       if_USE_SCROLL_HINTS(win->_line[line].oldindex = win->_line[line+n].oldindex);
+               }
+               for (line = bottom; line > bottom-n; line--) {
+                       for (j = 0; j <= win->_maxx; j ++)
+                               win->_line[line].text[j] = blank;
+                       if_USE_SCROLL_HINTS(win->_line[line].oldindex = _NEWINDEX);
+               }
+       }
+       touchline(win, top, bottom-top+1);
+}
+
+int
+wscrl(WINDOW *win, int n)
+{
+       T((T_CALLED("wscrl(%p,%d)"), win, n));
+
+       if (!win || !win->_scroll)
+               returnCode(ERR);
+
+       if (n == 0)
+               returnCode(OK);
+
+       if ((n > (win->_regbottom - win->_regtop)) || 
+           (-n > (win->_regbottom - win->_regtop)))
+           returnCode(ERR);
+
+       _nc_scroll_window(win, n, win->_regtop, win->_regbottom, _nc_background(win));
+
+       _nc_synchook(win);
+       returnCode(OK);
+}