ncurses 5.6
[ncurses.git] / ncurses / base / lib_scroll.c
index 197bb221a07c26c63e2f7c586f6852ffad70dae7..ac85bd55ea1d50f773e4c1b57350fa1d3b50277d 100644 (file)
@@ -1,5 +1,5 @@
 /****************************************************************************
- * Copyright (c) 1998 Free Software Foundation, Inc.                        *
+ * Copyright (c) 1998-2004,2006 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            *
  ****************************************************************************/
 
 /****************************************************************************
- *  Author: Zeyd M. Ben-Halim <zmbenhal@netcom.com> 1992,1995               *
+ *  Author: Thomas E. Dickey 1996-2003                                      *
+ *     and: Zeyd M. Ben-Halim <zmbenhal@netcom.com> 1992,1995               *
  *     and: Eric S. Raymond <esr@snark.thyrsus.com>                         *
  ****************************************************************************/
 
-
-
 /*
 **     lib_scroll.c
 **
 
 #include <curses.priv.h>
 
-MODULE_ID("$Id: lib_scroll.c,v 1.16 1998/02/11 12:13:55 tom Exp $")
+MODULE_ID("$Id: lib_scroll.c,v 1.26 2006/10/14 20:46:08 tom Exp $")
 
-void _nc_scroll_window(WINDOW *win, int const n, short const top, short const bottom, chtype blank)
+NCURSES_EXPORT(void)
+_nc_scroll_window(WINDOW *win,
+                 int const n,
+                 NCURSES_SIZE_T const top,
+                 NCURSES_SIZE_T const bottom,
+                 NCURSES_CH_T 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);
-               }
+    int limit;
+    int line;
+    int j;
+    size_t to_copy = (size_t) (sizeof(NCURSES_CH_T) * (win->_maxx + 1));
+
+    TR(TRACE_MOVE, ("_nc_scroll_window(%p, %d, %ld, %ld)",
+                   win, n, (long) top, (long) bottom));
+
+    if (top < 0
+       || bottom < top
+       || bottom > win->_maxy) {
+       TR(TRACE_MOVE, ("nothing to scroll"));
+       return;
+    }
+
+    /*
+     * 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) {
+       limit = top - n;
+       for (line = bottom; line >= limit && line >= 0; line--) {
+           TR(TRACE_MOVE, ("...copying %d to %d", line + 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 < limit && line <= win->_maxy; line++) {
+           TR(TRACE_MOVE, ("...filling %d", 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);
+    }
+
+    /* shift n lines upwards */
+    if (n > 0) {
+       limit = bottom - n;
+       for (line = top; line <= limit && line <= win->_maxy; 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 > limit && line >= 0; 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);
+
+    if_WIDEC({
+       if (WINDOW_EXT(win, addch_used) != 0) {
+           int next = WINDOW_EXT(win, addch_y) + n;
+           if (next < 0 || next > win->_maxy) {
+               TR(TRACE_VIRTPUT,
+                  ("Alert discarded multibyte on scroll"));
+               WINDOW_EXT(win, addch_y) = 0;
+           } else {
+               TR(TRACE_VIRTPUT, ("scrolled working position to %d,%d",
+                                  WINDOW_EXT(win, addch_y),
+                                  WINDOW_EXT(win, addch_x)));
+               WINDOW_EXT(win, addch_y) = next;
+           }
+       }
+    })
 }
 
-int
+NCURSES_EXPORT(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);
+    T((T_CALLED("wscrl(%p,%d)"), win, n));
 
-       _nc_scroll_window(win, n, win->_regtop, win->_regbottom, _nc_background(win));
+    if (!win || !win->_scroll) {
+       TR(TRACE_MOVE, ("...scrollok is false"));
+       returnCode(ERR);
+    }
 
+    if (n != 0) {
+       _nc_scroll_window(win, n, win->_regtop, win->_regbottom, win->_nc_bkgd);
        _nc_synchook(win);
-       returnCode(OK);
+    }
+    returnCode(OK);
 }