[Mono-bugs] [Bug 51741][Nor] New - System.IO.BinaryReader.PeekChar( ) modifies the underlying stream

bugzilla-daemon@bugzilla.ximian.com bugzilla-daemon@bugzilla.ximian.com
Thu, 4 Dec 2003 17:12:10 -0500 (EST)

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Changed by dev@6wardlaw.freeserve.co.uk.


--- shadow/51741	2003-12-04 17:12:10.000000000 -0500
+++ shadow/51741.tmp.14847	2003-12-04 17:12:10.000000000 -0500
@@ -0,0 +1,49 @@
+Bug#: 51741
+Product: Mono/Class Libraries
+Version: unspecified
+OS: Red Hat 8.0
+OS Details: 
+Status: NEW   
+Priority: Normal
+Component: CORLIB
+AssignedTo: mono-bugs@ximian.com                            
+ReportedBy: dev@6wardlaw.freeserve.co.uk               
+QAContact: mono-bugs@ximian.com
+TargetMilestone: ---
+Summary: System.IO.BinaryReader.PeekChar( ) modifies the underlying stream
+Description of Problem:
+PeekChar( ) on System.IO.BinaryReader modifies the underlying stream.
+Essentially, PeekChar( ) calls ReadChar( ) on the underlying stream but 
+doesn't reposition the stream before returning. The 'peeked' char is 
+placed into a buffer which is used for any subsequent ReadChar( ) call.
+This causes two problems.
+The first is that the underlying stream is not in the same state as it 
+was before the call.
+The second is that if the position of the stream is changed after a call 
+to PeekChar( ) a call to ReadChar( ) will return the invalid data from 
+the PeekChar( ) call.
+Steps to reproduce the problem:
+Create a test application which uses a BinaryReader and also manipulates 
+the underlying stream. ( attached )
+How often does this happen? 
+Additional Information:
+The Microsoft .net implementation of this method does not modify the 
+underlying stream. If the underlying stream is not seekable then PeekChar
+( ) return -1.