--- a/LineNumberReadStream.st	Sat Jul 26 10:13:10 2014 +0200
+++ b/LineNumberReadStream.st	Tue Sep 16 13:05:26 2014 +0200
@@ -129,22 +129,49 @@
 
     lineNumber := 1.
     (inputStream isPositionable) ifTrue:[
-	lineStartPosition := inputStream position.
+        lineStartPosition := inputStream position.
     ].
     filter := [:char |
-
-		char == Character cr ifTrue:[
-		    lineNumber := lineNumber + 1.
-		    inputStream isPositionable ifTrue:[
-			lineStartPosition := inputStream position.
-		    ].
-		].
-		char
-	      ].
+                char == Character cr ifTrue:[
+                    lineNumber := lineNumber + 1.
+                    lineStartPosition notNil ifTrue:[
+                        lineStartPosition := inputStream position.
+                    ].
+                ].
+                char
+              ].
 
     "Modified: 11.1.1997 / 16:58:42 / cg"
 ! !
 
+!LineNumberReadStream methodsFor:'positioning'!
+
+position:aPosition
+    "this method fails if inputStream is not positionable"
+
+    readAhead := nil.
+    inputStream position:aPosition.
+    (lineStartPosition notNil and:[aPosition < lineStartPosition]) ifTrue:[
+        "we detect backPosition over a single line, but not over multiple lines and 
+         no forward positioning!!"
+        lineNumber := lineNumber - 1.
+        lineStartPosition := aPosition.
+    ].
+!
+
+skip:numberToSkip
+    "this method fails if inputStream is not positionable"
+
+    readAhead := nil.
+    inputStream skip:numberToSkip.
+    (lineStartPosition notNil and:[numberToSkip < lineStartPosition negated]) ifTrue:[
+        "we detect backPosition over a single line, but not over multiple lines and 
+         no forward positioning!!"
+        lineNumber := lineNumber - 1.
+        lineStartPosition := lineStartPosition + numberToSkip.
+    ].
+! !
+
 !LineNumberReadStream methodsFor:'queries'!
 
 atEnd
@@ -156,34 +183,48 @@
 
 isLineNumberReadStream
     ^ true
-!
+! !
+
+!LineNumberReadStream methodsFor:'reading'!
+
+upToAll_positionBefore:aCollection
+    "read until a subcollection consisisting of the elements in aCollection is encountered.
+     Return everything read excluding the elements in aCollection.
+     The position is left before the collection; i.e. the next
+     read operations will return those elements.
+     If no such subcollection is encountered, all elements up to the end 
+     are read and returned.
+     See also #throughAll: which also reads up to some objects
+     but positions behind it and DOES include it in the returned
+     collection.
 
-peekOrNil
-    "peek ahead for the next character, or return nil"
+     This is a copy from PositionableStream>>#upToAll_positionBefore:.
+     It fails if inputStream is not positionable"
+
+    |answerStream element last|
 
-    readAhead notNil ifTrue:[
-	^ readAhead
+    last := aCollection last.
+    answerStream := WriteStream on:(self contentsSpecies new:100).
+    [(element := self nextOrNil) notNil] whileTrue:[
+        answerStream nextPut:element.
+        (element = last and:[answerStream endsBeforePositionWith:aCollection]) ifTrue:[
+            |backStep|
+            backStep := aCollection size negated.
+            self skip:backStep.
+            answerStream skip:backStep.
+            ^ answerStream contents
+        ].
     ].
-    ^ inputStream peekOrNil
-!
-
-position:aPosition
-    readAhead := nil.
-    inputStream position:aPosition
-!
-
-skip:numberToSkip
-    readAhead := nil.
-    inputStream skip:numberToSkip
+    ^ answerStream contents
 ! !
 
 !LineNumberReadStream class methodsFor:'documentation'!
 
 version
-    ^ '$Header: /cvs/stx/stx/libbasic2/LineNumberReadStream.st,v 1.10 2014-02-20 07:03:30 cg Exp $'
+    ^ '$Header: /cvs/stx/stx/libbasic2/LineNumberReadStream.st,v 1.11 2014-09-16 11:05:26 stefan Exp $'
 !
 
 version_CVS
-    ^ '$Header: /cvs/stx/stx/libbasic2/LineNumberReadStream.st,v 1.10 2014-02-20 07:03:30 cg Exp $'
+    ^ '$Header: /cvs/stx/stx/libbasic2/LineNumberReadStream.st,v 1.11 2014-09-16 11:05:26 stefan Exp $'
 ! !