From 53f79e426138004dfff3fec9f3e388be3318a070 Mon Sep 17 00:00:00 2001
From: Keith Winstein <keithw@mit.edu>
Date: Sat, 14 Apr 2012 01:11:57 -0400
Subject: [PATCH] Fix vttest "Funny scrolling regions" by ignoring some invalid
 scroll regions

Addresses #155 github issue.
---
 src/terminal/terminalfunctions.cc | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/terminal/terminalfunctions.cc b/src/terminal/terminalfunctions.cc
index 2dd69f7..ea3c938 100644
--- a/src/terminal/terminalfunctions.cc
+++ b/src/terminal/terminalfunctions.cc
@@ -316,6 +316,12 @@ void CSI_DECSTBM( Framebuffer *fb, Dispatcher *dispatch )
   int top = dispatch->getparam( 0, 1 );
   int bottom = dispatch->getparam( 1, fb->ds.get_height() );
 
+  if ( (bottom <= top)
+       || (top > fb->ds.get_height())
+       || (top == 0 && bottom == 1) ) {
+    return; /* invalid, xterm ignores */
+  }
+
   fb->ds.set_scrolling_region( top - 1, bottom - 1 );
   fb->ds.move_row( 0 );
   fb->ds.move_col( 0 );