ncurses 6.2 - patch 20200829

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

diff --git a/ncurses/base/lib_scroll.c b/ncurses/base/lib_scroll.c
index fe4e80804daef3de444430a3418cb7c587708ec3..ecc0ba569fe2c947ab967d30e2d51b01d984088c 100644 (file)
--- a/ncurses/base/lib_scroll.c
+++ b/ncurses/base/lib_scroll.c
@@ -1,5 +1,6 @@
 /****************************************************************************
- * Copyright (c) 1998-2009,2010 Free Software Foundation, Inc.              *
+ * Copyright 2019,2020 Thomas E. Dickey                                     *
+ * Copyright 1998-2010,2011 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            *
@@ -43,13 +44,13 @@
 
 #include <curses.priv.h>
 
-MODULE_ID("$Id: lib_scroll.c,v 1.28 2010/12/19 01:48:09 tom Exp $")
+MODULE_ID("$Id: lib_scroll.c,v 1.32 2020/02/02 23:34:34 tom Exp $")
 
 NCURSES_EXPORT(void)
 _nc_scroll_window(WINDOW *win,
                  int const n,
-                 NCURSES_SIZE_T const top,
-                 NCURSES_SIZE_T const bottom,
+                 int const top,
+                 int const bottom,
                  NCURSES_CH_T blank)
 {
     int limit;
@@ -77,11 +78,13 @@ _nc_scroll_window(WINDOW *win,
      * setup cost.  So there is no point in trying to be excessively
      * clever -- esr.
      */
+#define BottomLimit(n) ((n) >= 0 && (n) >= top)
+#define TopLimit(n)    ((n) <= win->_maxy && (n) <= bottom)
 
     /* shift n lines downwards */
     if (n < 0) {
        limit = top - n;
-       for (line = bottom; line >= limit && line >= 0; line--) {
+       for (line = bottom; line >= limit && BottomLimit(line); line--) {
            TR(TRACE_MOVE, ("...copying %d to %d", line + n, line));
            memcpy(win->_line[line].text,
                   win->_line[line + n].text,
@@ -89,7 +92,7 @@ _nc_scroll_window(WINDOW *win,
            if_USE_SCROLL_HINTS(win->_line[line].oldindex =
                                win->_line[line + n].oldindex);
        }
-       for (line = top; line < limit && line <= win->_maxy; line++) {
+       for (line = top; line < limit && TopLimit(line); line++) {
            TR(TRACE_MOVE, ("...filling %d", line));
            for (j = 0; j <= win->_maxx; j++)
                win->_line[line].text[j] = blank;
@@ -100,14 +103,14 @@ _nc_scroll_window(WINDOW *win,
     /* shift n lines upwards */
     if (n > 0) {
        limit = bottom - n;
-       for (line = top; line <= limit && line <= win->_maxy; line++) {
+       for (line = top; line <= limit && TopLimit(line); 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 (line = bottom; line > limit && BottomLimit(line); line--) {
            for (j = 0; j <= win->_maxx; j++)
                win->_line[line].text[j] = blank;
            if_USE_SCROLL_HINTS(win->_line[line].oldindex = _NEWINDEX);