"

 COPYRIGHT (c) 1989 by Claus Gittinger

	      All Rights Reserved

 This software is furnished under a license and may be used

 only in accordance with the terms of that license and with the

 inclusion of the above copyright notice.   This software may not

 be provided or otherwise made available to, or used by, any

 other person.  No title to or ownership of the software is

 hereby transferred.

"

ExternalStream subclass:#NonPositionableExternalStream

	instanceVariableNames:''

	classVariableNames:'StdInStream StdOutStream StdErrorStream'

	poolDictionaries:''

	category:'Streams-External'

!

!NonPositionableExternalStream primitiveDefinitions!

%{

#ifdef __openVMS__

# undef __new

#endif

#include <stdio.h>

#define _STDIO_H_INCLUDED_

%}

! !

!NonPositionableExternalStream class methodsFor:'documentation'!

copyright

"

 COPYRIGHT (c) 1989 by Claus Gittinger

	      All Rights Reserved

 This software is furnished under a license and may be used

 only in accordance with the terms of that license and with the

 inclusion of the above copyright notice.   This software may not

 be provided or otherwise made available to, or used by, any

 other person.  No title to or ownership of the software is

 hereby transferred.

"

!

documentation

"

    This class provides common protocol for all non-positionable,

    external streams. Concrete subclasses are terminal streams, pipe streams,

    PrinterStreams, Sockets etc.

    There are three special instances of this class, representing stdin,

    stdout and stderr of the smalltalk/X process (see Unix manuals, if you

    dont know what those are used for). These special streams are bound to

    to globals Stdin, Stdout and Stderr at early initialization time

    (see Smalltalk>>initializeStandardStreams).

    The name of this class is a historical leftover - it should be called

    'TTYStream' or similar.

    [author:]

        Claus Gittinger

"

! !

!NonPositionableExternalStream class methodsFor:'instance creation'!

forStderr

    "return a NonPositionableExternalStream object for writing to

     Unixes standard error output file descriptor"

    StdErrorStream isNil ifTrue:[

	StdErrorStream := self basicNew initializeForStderr

    ].

    ^ StdErrorStream

!

forStdin

    "return a NonPositionableExternalStream object for reading from

     Unixes standard input file descriptor"

    StdInStream isNil ifTrue:[

	StdInStream := self basicNew initializeForStdin

    ].

    ^ StdInStream

!

forStdout

    "return a NonPositionableExternalStream object for writing to

     Unixes standard output file descriptor"

    StdOutStream isNil ifTrue:[

	StdOutStream := self basicNew initializeForStdout

    ].

    ^ StdOutStream

! !

!NonPositionableExternalStream methodsFor:'error handling'!

positionError

    "notify that this stream has no concept of a position"

    ^ PositionErrorSignal raiseRequestWith:self in:thisContext sender

! !

!NonPositionableExternalStream methodsFor:'positioning'!

position

    "catch position - there is none here"

    ^ self positionError

!

position:aPosition

    "catch position - there is none here"

    ^ self positionError

!

skip:numberToSkip

    "skip count objects, return the receiver"

    "dont know how to unread ..."

    numberToSkip < 0 ifTrue:[

	^ self error:'stream is not positionable'

    ].

    numberToSkip timesRepeat:self next

! !

!NonPositionableExternalStream methodsFor:'printing & storing'!

printOn:aStream

    "append a printed representation of the receiver on aStream"

    self == Stdin ifTrue:[

    ].

	^ self

    ].

    super printOn:aStream

!

storeOn:aStream

    "append a printed representation of the receiver on aStream, from

     which the receiver can be reconstructed."

    ((self == Stdin)

    or:[self == Stdout

    or:[self == Stderr]]) ifTrue:[

	^ self printOn:aStream

    ].

    super storeOn:aStream

! !

!NonPositionableExternalStream methodsFor:'private'!

initializeForStderr

    "setup for writing to stderr"

    mode := #readwrite.

    buffered := false.

%{

    OBJ fp;

    __INST(filePointer) = fp = __MKOBJ(stderr); __STORE(self, fp);

%}

!

initializeForStdin

    "setup for reading stdin"

    mode := #readonly.

    buffered := true.

%{

    OBJ fp;

    __INST(filePointer) = fp = __MKOBJ(stdin); __STORE(self, fp);

%}

!

initializeForStdout

    "setup for writing to stdout"

    mode := #readwrite.

    buffered := false.

%{

    OBJ fp;

    __INST(filePointer) = fp = __MKOBJ(stdout); __STORE(self, fp);

%}

!

reOpen

    "reopen the stream after an image restart.

     If I am one of the standard streams, reopen is easy"

    (self == StdInStream) ifTrue:[

	^ self initializeForStdin

    ].

    (self == StdOutStream) ifTrue:[

	^ self initializeForStdout

    ].

    (self == StdErrorStream) ifTrue:[

	^ self initializeForStderr

    ].

    ^ super reOpen

! !

!NonPositionableExternalStream methodsFor:'queries'!

isPositionable

    "return true, if the stream supports positioning (this one is not)"

    ^ false

! !

!NonPositionableExternalStream class methodsFor:'documentation'!

version

! !