"{ Package: 'stx:goodies/xtreams/terminals' }"

"{ NameSpace: Xtreams }"

ExternalReadStream subclass:#FileReadStream

	instanceVariableNames:'filename position'

	classVariableNames:''

	poolDictionaries:''

	category:'Xtreams-Terminals'

!

FileReadStream comment:'Reads from a file. The stream is usually created by sending #reading to a Filename. However the actual terminal is an IOAccessor. The original filename is accessible through the IOAccessor. The stream is binary and is naturally positionable.

{{{

	| file |

	file := ObjectMemory imageName asFilename reading.

	[ file read: 13 ] ensure: [ file close ]

}}}

As a convenience, sending #reading to a Filename of a directory will create a stream of all filenames in that directory.

{{{

	''/tmp'' asFilename reading rest

}}}

Instance Variables

	position        <Integer> current position of the stream

'

!

!FileReadStream methodsFor:'accessing'!

get

	| object |

	object := super get.

	position := position + 1.

	^object

!

read: anInteger into: aSequenceableCollection at: startIndex

	super read: anInteger into: aSequenceableCollection at: startIndex.

	position := position + anInteger.

	^anInteger

! !

!FileReadStream methodsFor:'initialize-release'!

on: anAccessor

	super on: anAccessor.

	position := 0

! !

!FileReadStream methodsFor:'private'!

bytesForRead

	"Ideally we'd ask for the fileSize and subtract that from our position, but calling #fileSize is a slow primitive"

	^cache size

!

incompleteRead: incomplete

	position := position + incomplete count.

	super incompleteRead: incomplete.

!

readBytes:count into:aByteBuffer startingAt:firstIndex

    ^source readBytes:count into:aByteBuffer startingAt:firstIndex

!

setFilename: fn

    filename := fn

! !

!FileReadStream methodsFor:'seeking'!

++ anInteger

	| count |

	anInteger < 0 ifTrue: [ ^self -- anInteger negated ].

	count := self available min: anInteger.

	position := position + count.

	source seekTo: position from: #begin.

	cacheDataSize := cachePosition := 0.

	count < anInteger ifTrue: [(Incomplete count: count) raise].

	^anInteger

!

-- anInteger

	| count |

	anInteger < 0 ifTrue: [ ^self ++ anInteger negated ].

	count := position min: anInteger.

	position := position - count.

	source seekTo: position from: #begin.

	cacheDataSize := cachePosition := 0.

	anInteger = count ifTrue: [^anInteger].

	(Incomplete count: count) raise

!

length

	^filename fileSize

!

position

	^position

!

position: aPosition

	| available |

	aPosition < 0 ifTrue: [ Incomplete zero raise ].

	available := aPosition min: self length.

	source seekTo: available from: #begin.

	position := available.

	cacheDataSize := cachePosition := 0.

	available = aPosition ifTrue: [^aPosition].

	(Incomplete count: available) raise

! !

!FileReadStream methodsFor:'testing'!

isPositionable

	^true

! !

!FileReadStream class methodsFor:'documentation'!

version_HG

    ^ '$Changeset: <not expanded> $'

! !