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Diffstat (limited to 'ncurses/base/lib_scroll.c')
-rw-r--r--ncurses/base/lib_scroll.c14
1 files changed, 8 insertions, 6 deletions
diff --git a/ncurses/base/lib_scroll.c b/ncurses/base/lib_scroll.c
index 8684e2519294..000f128fb0d6 100644
--- a/ncurses/base/lib_scroll.c
+++ b/ncurses/base/lib_scroll.c
@@ -1,5 +1,5 @@
/****************************************************************************
- * Copyright (c) 1998-2010,2011 Free Software Foundation, Inc. *
+ * Copyright (c) 1998-2011,2019 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 *
@@ -43,7 +43,7 @@
#include <curses.priv.h>
-MODULE_ID("$Id: lib_scroll.c,v 1.29 2011/10/22 16:34:50 tom Exp $")
+MODULE_ID("$Id: lib_scroll.c,v 1.31 2019/08/03 22:27:55 tom Exp $")
NCURSES_EXPORT(void)
_nc_scroll_window(WINDOW *win,
@@ -77,11 +77,13 @@ _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 +91,7 @@ _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 +102,14 @@ _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);