1 files changed, 19 insertions, 14 deletions
diff --git a/zcmpdiff.cc b/zcmpdiff.cc
index bbbc87e..961a32a 100644
--- a/zcmpdiff.cc
+++ b/zcmpdiff.cc
@@ -31,21 +31,26 @@ int open_instream( const std::string & input_filename )
 
 int open_other_instream( std::string & name )
   {
-  const int eindex = extension_index( name );
-  if( eindex >= 0 && enabled_format( -1 ) )
-    {					// open uncompressed version
-    name.resize( name.size() - std::strlen( extension_from( eindex ) ) );
-    name += extension_to( eindex );
-    return open( name.c_str(), O_RDONLY | O_BINARY );
+  const int eindex = extension_index( name );	// search extension
+  if( eindex >= 0 && enabled_format( -1 ) )	// open uncompressed version
+    {
+    std::string s( name, 0, name.size() - std::strlen( extension_from( eindex ) ) );
+    s += extension_to( eindex );
+    const int infd = open( s.c_str(), O_RDONLY | O_BINARY );
+    if( infd >= 0 ) { name = s; return infd; }
+    }
+  const int eformat = extension_format( eindex );
+  for( int i = 0; i < num_formats; ++i )	// search compressed version
+    {
+    const int format_index = format_order[i];
+    if( eformat != format_index && enabled_format( format_index ) )
+      {
+      std::string s( name, 0, name.size() - std::strlen( extension_from( eindex ) ) );
+      s += simple_extensions[format_index];
+      const int infd = open( s.c_str(), O_RDONLY | O_BINARY );
+      if( infd >= 0 ) { name = s; return infd; }
+      }
     }
-  if( eindex < 0 )			// search compressed version
-    for( int i = 0; i < num_formats; ++i )
-      if( enabled_format( format_order[i] ) )
-        {
-        const std::string s( name + simple_extensions[format_order[i]] );
-        const int infd = open( s.c_str(), O_RDONLY | O_BINARY );
-        if( infd >= 0 ) { name = s; return infd; }
-        }
   return -1;
   }