From 9658b01431cd7ff6344d7787f855179e73fe81a7 Mon Sep 17 00:00:00 2001
From: Leon Bottou <leon@bottou.org>
Date: Mon, 8 Apr 2019 22:55:38 -0400
Subject: fix bug #298


diff --git a/libdjvu/GBitmap.h b/libdjvu/GBitmap.h
index e8e0c9b..ca89a19 100644
--- a/libdjvu/GBitmap.h
+++ b/libdjvu/GBitmap.h
@@ -566,7 +566,7 @@ GBitmap::operator[](int row)
 {
   if (!bytes) 
     uncompress();
-  if (row<0 || row>=nrows) {
+  if (row<0 || row>=nrows || !bytes) {
 #ifndef NDEBUG
     if (zerosize < bytes_per_row + border)
       G_THROW( ERR_MSG("GBitmap.zero_small") );
@@ -581,7 +581,7 @@ GBitmap::operator[](int row) const
 {
   if (!bytes) 
     ((GBitmap*)this)->uncompress();
-  if (row<0 || row>=nrows) {
+  if (row<0 || row>=nrows || !bytes) {
 #ifndef NDEBUG
     if (zerosize < bytes_per_row + border)
       G_THROW( ERR_MSG("GBitmap.zero_small") );