"

 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.

"

PositionableStream subclass:#WriteStream

       instanceVariableNames:'writeLimit'

       classVariableNames:''

       poolDictionaries:''

       category:'Streams'

!

WriteStream comment:'

COPYRIGHT (c) 1989 by Claus Gittinger

	      All Rights Reserved

'!

!WriteStream 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.

"

!

version

"

"

!

documentation

"

    Streams for writing into - this implementation currently DOES change the 

    identity if the streamed-upon collection IF it cannot grow easily. 

    Collections which cannot grow easily are for example: Array, ByteArray and String.

    Thus it is slightly incompatible to ST-80 since 'aStream contents' does 

    not always return the original collection. This may change.

"

! !

!WriteStream class methodsFor:'instance creation'!

on:aCollection from:start to:last

    "create and return a new stream for writing onto aCollection, where

     writing is limited to the elements in the range start to last."

    |newStream|

    newStream := super on:aCollection from:start to:last.

    newStream writeLimit:last.

    ^ newStream

! !

!WriteStream methodsFor:'accessing'!

contents

    "return the current contents (a collection) of the stream"

    |lastIndex|

    lastIndex := position - 1.

    collection size == lastIndex ifFalse:[

	collection isFixedSize ifTrue:[

	    "

	     grow is expensive - return a copy.

	     (is this what users of writeStream expect ?

	    "

	    collection := collection copyFrom:1 to:lastIndex

	] ifFalse:[

	    collection grow:lastIndex

	]

    ].

    ^ collection

!

writeLimit:aNumber

    "set the writeLimit, thats the position after which writing is

     prohibited (i.e. silently ignored)."

    writeLimit := aNumber

! !

!WriteStream methodsFor:'reading'!

next

    "catch read access to write stream - report an error"

    self shouldNotImplement

!

peek

    "catch read access to write stream - report an error"

    self shouldNotImplement

! !

!WriteStream methodsFor:'writing'!

nextPut:anObject

    "append the argument, anObject to the stream"

%{  /* NOCONTEXT */

    REGISTER int pos;

    unsigned ch;

    OBJ coll;

    OBJ p, l;

    coll = _INST(collection);

    p = _INST(position);

    if (__isNonNilObject(coll) && __isSmallInteger(p)) {

	pos = _intVal(p);

	l = _INST(writeLimit);

	if ((l == nil)

	    OBJ cls;

	    if (cls == String) {

		if (__isCharacter(anObject) 

		 && (pos <= _stringSize(coll))) {

		    ch = _intVal(_characterVal(anObject));

		    if ((ch >= 0) && (ch <= 255)) {

			    _INST(readLimit) = _MKSMALLINT(pos + 1);

		    }

		}

	    } else {

		    if (__isSmallInteger(anObject) 

		     && ((ch = _intVal(anObject)) >= 0)

		     && (ch <= 255)

		     && (pos <= _byteArraySize(coll))) {

			    _INST(readLimit) = _MKSMALLINT(pos + 1);

		    }

		    }

		}

	    }

	}

    }

%}.

    (writeLimit isNil

    or:[position <= writeLimit]) ifTrue:[

	(position > collection size) ifTrue:[self growCollection].

	collection at:position put:anObject.

	(position > readLimit) ifTrue:[readLimit := position].

	position := position + 1.

    ].

    ^anObject

!

next:count put:anObject

    "append anObject count times to the receiver.

     Redefined to avoid count grows of the underlying collection -

     instead a single grow on the final size is performed."

    |final|

    (collection isNil or:[writeLimit notNil]) ifTrue:[

	^ super next:count put:anObject

    ].

    final := position + count - 1.

    (final > collection size) ifTrue:[

	self growCollection:final

    ].

    position to:final do:[:index |

	collection at:index put:anObject.

    ].

    position := position + count.

    (position > readLimit) ifTrue:[readLimit := position - 1].

    ^ anObject

!

nextPutAll:aCollection

    "append all elements of the argument, aCollection to the stream.

     Redefined to avoid count grows of the underlying collection -

     instead a single grow on the final size is performed."

    |nMore final|

    collection isNil ifTrue:[

	^ super nextPutAll:aCollection

    ].

    nMore := aCollection size.

    final := position + nMore - 1.

    (writeLimit notNil

    and:[final > writeLimit]) ifTrue:[

	final := writeLimit.

	nMore := final - position + 1

    ].

    (final > collection size) ifTrue:[

	self growCollection:final

    ].

    collection replaceFrom:position

			to:final

		      with:aCollection 

		startingAt:1.

    position := position + nMore.

    (position > readLimit) ifTrue:[readLimit := position - 1].

    ^ aCollection

! !

!WriteStream methodsFor:'ignored'!

bold

    "change font to bold - ignored here.

     - this allows WriteStreams to be compatible to PrinterStreams"

!

italic

    "change font to italic - ignored here.

     - this allows WriteStreams to be compatible to PrinterStreams"

!

boldItalic

    "change font to italic - ignored here.

     - this allows WriteStreams to be compatible to PrinterStreams"

!

normal

    "change font to normal - ignored here.

     - this allows WriteStreams to be compatible to PrinterStreams"

! !

!WriteStream methodsFor:'private'!

growCollection

    self growCollection:10

!

growCollection:minNewSize

    "grow the streamed collection to at least minNewSize"

    |oldSize newSize newColl|

    oldSize := collection size.

    (oldSize == 0) ifTrue:[

	newSize := minNewSize

    ] ifFalse:[

	newSize := oldSize * 2.

	[newSize < minNewSize] whileTrue:[

	    newSize := newSize * 2

	]

    ].

    collection isFixedSize ifTrue:[

	newColl := collection species new:newSize.

	newColl replaceFrom:1 to:oldSize with:collection startingAt:1.

	collection := newColl

    ] ifFalse:[

	collection grow:newSize

    ].

! !