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"
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COPYRIGHT (c) 1989-93 by Claus Gittinger
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All Rights Reserved
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This software is furnished under a license and may be used
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only in accordance with the terms of that license and with the
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inclusion of the above copyright notice. This software may not
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be provided or otherwise made available to, or used by, any
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other person. No title to or ownership of the software is
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hereby transferred.
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"
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PositionableStream subclass:#WriteStream
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instanceVariableNames:'writeLimit'
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classVariableNames:''
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poolDictionaries:''
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category:'Streams'
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!
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WriteStream comment:'
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COPYRIGHT (c) 1989-93 by Claus Gittinger
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All Rights Reserved
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Streams for writing into - this implementation currently DOES change the identity if the
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streamed-upon collection if it cannot grow. Thus its slightly incompatible to ST-80 since
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aStream contents does not always return the original collection. This will change soon.
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%W% %E%
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'!
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!WriteStream class methodsFor:'instance creation'!
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on:aCollection from:start to:last
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"create and return a new stream for writing onto aCollection, where
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writing is limited to the elements in the range start to last."
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|newStream|
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newStream := super on:aCollection from:start to:last.
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newStream writeLimit:last.
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^ newStream
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! !
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!WriteStream methodsFor:'private'!
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on:aCollection
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"create and return a new stream for writing onto aCollection"
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super on:aCollection.
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writeLimit := readLimit
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! !
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!WriteStream methodsFor:'accessing'!
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contents
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"return the current contents (a collection) of the stream"
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collection size == (position - 1) ifFalse:[
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collection isFixedSize ifTrue:[
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collection := collection copyFrom:1 to:(position - 1)
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] ifFalse:[
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collection grow:(position - 1)
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]
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].
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^ collection
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!
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writeLimit:aNumber
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"set the writeLimit, thats the position after which writing is
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prohibited."
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(aNumber < collection size) ifTrue:[writeLimit := aNumber]
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! !
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!WriteStream methodsFor:'reading/writing'!
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next
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"catch read access to write stream"
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^ self error:'WriteStreams cannot read'
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!
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peek
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"catch read access to write stream"
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^ self error:'WriteStreams cannot read'
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!
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nextPut:anObject
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"append the argument, anObject to the stream"
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(position > collection size) ifTrue:[self growCollection].
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collection at:position put:anObject.
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(position > readLimit) ifTrue:[readLimit := position].
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position := position + 1.
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^anObject
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!
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nextPutAll:aCollection
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"append all elements of the argument, aCollection to the stream"
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|nMore final|
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nMore := aCollection size.
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final := position + nMore - 1.
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(final > collection size) ifTrue:[
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self growCollection:final
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].
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collection replaceFrom:position
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to:final
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with:aCollection
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startingAt:1.
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position := position + nMore.
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(position > readLimit) ifTrue:[readLimit := position - 1].
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^ aCollection
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!
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cr
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"append a carriage-return to the stream"
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self nextPut:(Character cr)
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!
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tab
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"append a tab-character to the stream"
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self nextPut:(Character tab)
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!
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crTab
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"append a carriage-return followed by a tab to the stream"
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self nextPut:(Character cr).
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self nextPut:(Character tab)
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!
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space
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"append a space character to the receiver-stream"
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self nextPut:(Character space)
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!
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spaces:count
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"append count space-characters to the receiver-stream"
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1 to:count do:[:dummy |
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self nextPut:(Character space)
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]
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!
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ff
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"append a form-feed (new-pagee) to the receiver-stream"
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self nextPut:(Character ff)
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! !
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!WriteStream methodsFor:'private'!
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growCollection
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|oldSize newSize newColl|
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oldSize := collection size.
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(oldSize == 0) ifTrue:[
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newSize := 10
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] ifFalse:[
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newSize := oldSize * 2
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].
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collection isFixedSize ifTrue:[
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newColl := collection species new:newSize.
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newColl replaceFrom:1 to:oldSize with:collection startingAt:1.
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collection := newColl
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] ifFalse:[
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collection grow:newSize.
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].
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writeLimit := newSize
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!
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growCollection:minNewSize
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|oldSize newSize newColl|
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oldSize := collection size.
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(oldSize == 0) ifTrue:[
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newSize := minNewSize
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] ifFalse:[
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newSize := oldSize * 2.
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[newSize < minNewSize] whileTrue:[
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newSize := newSize * 2
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]
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].
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collection isFixedSize ifTrue:[
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newColl := collection species new:newSize.
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newColl replaceFrom:1 to:oldSize with:collection startingAt:1.
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collection := newColl
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] ifFalse:[
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collection grow:newSize
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].
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writeLimit := newSize
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! !
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