--- zutils-1.7/zcat.cc	2018-02-13 19:10:41.000000000 +0000
+++ zutils-1.8-pre2/zcat.cc	2018-07-31 21:49:02.000000000 +0000
@@ -227,10 +230,11 @@
          const Cat_options & cat_options )
   {
   enum { buffer_size = 4096 };
-  // buffer with space for sentinel newline at the end
+    // buffer with space for sentinel newline at the end
   uint8_t * const inbuf = new uint8_t[buffer_size+1];
-  // buffer with space for character quoting and 255-digit line number
-  uint8_t * const outbuf = new uint8_t[(4*buffer_size)+256];
+    // buffer with space for character quoting, 255-digit line number and
+    // worst case flushing respect to inbuf.
+  uint8_t * const outbuf = new uint8_t[(5*buffer_size)+256];
   int retval = 0;
   Children children;
   if( !set_data_feeder( input_filename, &infd, children, format_index ) )