'From Smalltalk/X, Version:3.1.5 on 11-apr-1997 at 6:49:46 pm'                  !

ImageReader subclass:#RIFFReader
	instanceVariableNames:'chunkSize streamTypes'
	classVariableNames:'UnsupportedFormatErrorSignal'
	poolDictionaries:''
	category:'Graphics-Images-Support'
!

!RIFFReader class methodsFor:'documentation'!

documentation
"
    Helper to read RIFF files.
"
! !

!RIFFReader class methodsFor:'class initialization'!

initialize
    UnsupportedFormatErrorSignal isNil ifTrue:[
        UnsupportedFormatErrorSignal := ErrorSignal newSignalMayProceed:true.
        UnsupportedFormatErrorSignal nameClass:self message:#unsupportedFormatErrorSignal.
    ].

    "
     RIFFReader initialize
    "

    "Created: 4.4.1997 / 22:35:52 / cg"
    "Modified: 5.4.1997 / 16:12:16 / cg"
! !

!RIFFReader class methodsFor:'testing'!

isRIFFFile:aFileName
    "return true, if aFileName contains RIFF-encoded data"

    |data1 inStream|

    inStream := self streamReadingFile:aFileName.
    inStream isNil ifTrue:[^ false].
    inStream binary.

    data1 := String new:4.
    inStream nextBytes:4 into:data1.
    inStream close.

    ^ (data1 = 'RIFF')

    "
     RIFFReader isRIFFFile:'bitmaps/magtape.xpm'    
     RIFFReader isRIFFFile:'/home2/pd_stuff/movies/avi/drlair.avi'      
    "

    "Created: 4.4.1997 / 22:35:52 / cg"
    "Modified: 5.4.1997 / 16:12:16 / cg"
! !

!RIFFReader methodsFor:'reading from stream'!

getChunk
    "get a single chunk"

    |id s sel streamNr streamType|

    'getChunk -> ' infoPrint.

    id := '    '.
    inStream nextBytes:4 into:id startingAt:1.
    chunkSize := inStream nextLongMSB:false.

    (id at:4) == Character space ifTrue:[
        id := id copyTo:3
    ].

    (id at:1) isDigit ifTrue:[
        streamNr := Number readFrom:(id copyTo:2).
        streamType := streamTypes at:(streamNr + 1).
        s := 'getChunk_' , streamType , '_' , (id copyFrom:3).       
    ] ifFalse:[
        s := 'getChunk_' , id.
    ].
    sel := s asSymbolIfInterned.
    (sel isNil or:[(self respondsTo:sel) not]) ifTrue:[
        '[' infoPrint. s infoPrint. '] ' infoPrint.
        sel := #'getChunk_Unknown'    
    ].

    self perform:sel.

    '' infoPrintCR.

    "Created: 5.4.1997 / 16:29:40 / cg"
    "Modified: 11.4.1997 / 14:00:42 / cg"
!

getChunk_LIST
    "process a LIST chunk"

    'getChunk_LIST' infoPrint.

    inStream skip:4.

    "
     AVIReader fromFile:'/home2/pd_stuff/movies/avi/hangldm.avi'      
    "

    "Created: 4.4.1997 / 23:18:33 / cg"
    "Modified: 5.4.1997 / 16:12:16 / cg"
!

getChunk_RIFF
    "process a RIFF chunk"

    'getChunk_RIFF' infoPrint.

    inStream skip:4.

    "
     AVIReader fromFile:'/home2/pd_stuff/movies/avi/hangldm.avi'      
    "

    "Created: 4.4.1997 / 23:18:08 / cg"
    "Modified: 5.4.1997 / 16:12:16 / cg"
!

getChunk_Unknown
    "ignore any other chunk"

    'getChunk_Unknown -> ' infoPrint.

    self skipChunk

    "
     AVIReader fromFile:'/home2/pd_stuff/movies/avi/hangldm.avi'      
    "

    "Created: 5.4.1997 / 00:03:43 / cg"
    "Modified: 5.4.1997 / 16:12:16 / cg"
!

skipChunk
    "skip a chunk"

    |sz|

    'skipChunk' infoPrint.

    sz := chunkSize.
    (sz bitTest:1) ifTrue:[
        sz := sz + 1
    ].

    inStream skip:sz.

    "
     AVIReader fromFile:'/home2/pd_stuff/movies/avi/hangldm.avi'      
    "

    "Created: 5.4.1997 / 14:13:43 / cg"
    "Modified: 5.4.1997 / 16:12:16 / cg"
! !

!RIFFReader class methodsFor:'documentation'!

version
    ^ '$Header: /cvs/stx/stx/libview2/RIFFReader.st,v 1.1 1997-04-14 11:59:34 cg Exp $'
! !
RIFFReader initialize!