release/src/router/libncurses/ncurses/base/lib_scroll.c

   1 /****************************************************************************
   2  * Copyright (c) 1998-2009,2010 Free Software Foundation, Inc.              *
   3  *                                                                          *
   4  * Permission is hereby granted, free of charge, to any person obtaining a  *
   5  * copy of this software and associated documentation files (the            *
   6  * "Software"), to deal in the Software without restriction, including      *
   7  * without limitation the rights to use, copy, modify, merge, publish,      *
   8  * distribute, distribute with modifications, sublicense, and/or sell       *
   9  * copies of the Software, and to permit persons to whom the Software is    *
  10  * furnished to do so, subject to the following conditions:                 *
  11  *                                                                          *
  12  * The above copyright notice and this permission notice shall be included  *
  13  * in all copies or substantial portions of the Software.                   *
  14  *                                                                          *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS  *
  16  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF               *
  17  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.   *
  18  * IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,   *
  19  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR    *
  20  * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR    *
  21  * THE USE OR OTHER DEALINGS IN THE SOFTWARE.                               *
  22  *                                                                          *
  23  * Except as contained in this notice, the name(s) of the above copyright   *
  24  * holders shall not be used in advertising or otherwise to promote the     *
  25  * sale, use or other dealings in this Software without prior written       *
  26  * authorization.                                                           *
  27  ****************************************************************************/
  28
  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  ****************************************************************************/
  34
  35 /*
  36 **      lib_scroll.c
  37 **
  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)
  41 **
  42 */
  43
  44 #include <curses.priv.h>
  45
  46 MODULE_ID("$Id: lib_scroll.c,v 1.28 2010/12/19 01:48:09 tom Exp $")
  47
  48 NCURSES_EXPORT(void)
  49 _nc_scroll_window(WINDOW *win,
  50                   int const n,
  51                   NCURSES_SIZE_T const top,
  52                   NCURSES_SIZE_T const bottom,
  53                   NCURSES_CH_T blank)
  54 {
  55     int limit;
  56     int line;
  57     int j;
  58     size_t to_copy = (sizeof(NCURSES_CH_T) * (size_t) (win->_maxx + 1));
  59
  60     TR(TRACE_MOVE, ("_nc_scroll_window(%p, %d, %ld, %ld)",
  61                     (void *) win, n, (long) top, (long) bottom));
  62
  63     if (top < 0
  64         || bottom < top
  65         || bottom > win->_maxy) {
  66         TR(TRACE_MOVE, ("nothing to scroll"));
  67         return;
  68     }
  69
  70     /*
  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
  78      * clever -- esr.
  79      */
  80
  81     /* shift n lines downwards */
  82     if (n < 0) {
  83         limit = top - n;
  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,
  88                    to_copy);
  89             if_USE_SCROLL_HINTS(win->_line[line].oldindex =
  90                                 win->_line[line + n].oldindex);
  91         }
  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);
  97         }
  98     }
  99
 100     /* shift n lines upwards */
 101     if (n > 0) {
 102         limit = bottom - n;
 103         for (line = top; line <= limit && line <= win->_maxy; line++) {
 104             memcpy(win->_line[line].text,
 105                    win->_line[line + n].text,
 106                    to_copy);
 107             if_USE_SCROLL_HINTS(win->_line[line].oldindex =
 108                                 win->_line[line + n].oldindex);
 109         }
 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);
 114         }
 115     }
 116     touchline(win, top, bottom - top + 1);
 117
 118     if_WIDEC({
 119         if (WINDOW_EXT(win, addch_used) != 0) {
 120             int next = WINDOW_EXT(win, addch_y) + n;
 121             if (next < 0 || next > win->_maxy) {
 122                 TR(TRACE_VIRTPUT,
 123                    ("Alert discarded multibyte on scroll"));
 124                 WINDOW_EXT(win, addch_y) = 0;
 125             } else {
 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;
 130             }
 131         }
 132     })
 133 }
 134
 135 NCURSES_EXPORT(int)
 136 wscrl(WINDOW *win, int n)
 137 {
 138     T((T_CALLED("wscrl(%p,%d)"), (void *) win, n));
 139
 140     if (!win || !win->_scroll) {
 141         TR(TRACE_MOVE, ("...scrollok is false"));
 142         returnCode(ERR);
 143     }
 144
 145     if (n != 0) {
 146         _nc_scroll_window(win, n, win->_regtop, win->_regbottom, win->_nc_bkgd);
 147         _nc_synchook(win);
 148     }
 149     returnCode(OK);
 150 }