--- a/CompressionStream.st	Thu Aug 22 10:29:44 2002 +0200
+++ b/CompressionStream.st	Fri Aug 23 08:08:01 2002 +0200
@@ -582,8 +582,6 @@
     "
     |data count offset species|
 
-    mode == #readonly ifFalse:[ self errorReadOnly ].
-
     species := self contentsSpecies.
 
     self canReadWithoutBlocking ifFalse:[
@@ -606,9 +604,16 @@
     "
     |n avail|
 
-    mode == #readonly ifFalse:[ self errorReadOnly ].
     n := count.
 
+    n > 0 ifFalse:[
+        n ~~ 0 ifTrue:[
+            "dont know how to unread ..."
+            PositionErrorSignal raiseRequest
+        ].
+        ^ self
+    ].
+
     [ self canReadWithoutBlocking ] whileTrue:[
         avail := readLimit - position.