"{ Package: 'stx:libview2' }"

Object subclass:#RIFFReader

	instanceVariableNames:'inStream chunkSize streamTypes client'

	category:'System-Support-FileFormats'

    RIFF is the abstract base-format used for a whole bunch of concrete file formats:

        WAV, AVI, AIF etc.

    Concrete formats must be parsed by concrete readers.

    Use:

        define your own concrete reader, with methods getChunk_FOO:,

        for each chunk type FOO you want to parse there.

        Define your reader as a client to this reader, and let it processChunks.

        See AVIReader for a concrete example.

     RIFFReader isRIFFFile: '/usr/share/sounds/alsa/test.wav'      

!RIFFReader methodsFor:'accessing'!

addStream:type

    streamTypes add:type

!

client

    "return the value of the instance variable 'client' (automatically generated)"

    ^ client

!

client:something

    "set the value of the instance variable 'client' (automatically generated)"

    client := something.

!

streamTypes:something

    "set the value of the instance variable 'streamTypes' (automatically generated)"

    streamTypes := something.

! !

    client := self.

    self processStream:aStream

     RIFFReader fromFile:'/phys/exept/home/pd_stuff/movies/avi/hangldm.avi'      

     RIFFReader fromFile:'/phys/exept/opt/office52/share/gallery/sounds/gong.wav'      

     AVIReader fromFile:'/phys/exept/home/pd_stuff/movies/avi/hangldm.avi'      

     WAVFileReader fromFile:'/phys/exept/opt/office52/share/gallery/sounds/gong.wav'      

     AIFFFileReader fromFile:'/phys/exept/opt/office52/share/gallery/sounds/gong.wav'      

    |id sel sTyp|

    (id at:1) == $0 ifTrue:[

        sTyp := '_Unknown'.

        streamTypes notNil ifTrue:[

            sTyp := streamTypes at:((id at:2) digitValue + 1) ifAbsent:nil.

        ].

        sel := 'getChunk_' , sTyp , '_' , (id copyFrom:3), ':'.

"/id infoPrint. ' -> ' infoPrint. sel infoPrintCR.

        sel := sel asSymbolIfInterned.

        (sel isNil or:[(self respondsTo:sel) not]) ifTrue:[

            sel := 'getChunk_' , sTyp , '_Unknown:'.

"/'  ' infoPrint. id infoPrint. ' -> ' infoPrint. sel infoPrintCR.

            sel := sel asSymbolIfInterned.

            (sel isNil or:[(self respondsTo:sel) not]) ifTrue:[

                '[' infoPrint. ('getChunk_' , sTyp , '_' , (id copyFrom:3)) infoPrint. '] ' infoPrint.

                sel := #'getChunk_Unknown:'.    

"/'    ' infoPrint. id infoPrint. ' -> ' infoPrint. sel infoPrintCR.

            ].

        (id at:4) == Character space ifTrue:[

            id := id copyTo:3

        ].

        sel := ('getChunk_' , id , ':') asSymbolIfInterned.

        (sel isNil or:[(self respondsTo:sel) not]) ifTrue:[

            '[' infoPrint. ('getChunk_' , id) infoPrint. '] ' infoPrint.

            sel := #'getChunk_Unknown:'    

        ].

"/id infoPrint. ' -> ' infoPrint. sel infoPrintCR.

    client perform:sel with:chunkSize ifNotUnderstood:[self perform:sel with:chunkSize].

    "

     RIFFReader fromFile:'/phys/exept/home/pd_stuff/movies/avi/hangldm.avi'      

     AVIReader fromFile:'/phys/exept/home/pd_stuff/movies/avi/hangldm.avi'      

    "

    "Created: 4.4.1997 / 22:50:13 / cg"

    "Modified: 5.4.1997 / 15:47:48 / cg"

getChunk_DISP:chunkSize

    "process (ignore) a DISP chunk"

    'getChunk_DISP -> ' infoPrint.

    self skipChunk:chunkSize

    "Created: 5.4.1997 / 15:19:10 / cg"

!

getChunk_JUNK:chunkSize

    "ignore JUNK chunk"

    'getChunk_JUNK -> ' infoPrint.

    self skipChunk:chunkSize

!

getChunk_LIST:chunkSize

getChunk_RIFF:chunkSize

getChunk_Unknown:chunkSize

    self skipChunk:chunkSize

!

processStream:aStream

    "read RIFF chunks from aStream. Process chunks in getChunkXXX methods

     (usually redefined in concrete reader classes."

    inStream := aStream.

    inStream binary.

    [inStream atEnd] whileFalse:[

        client perform:#getChunk ifNotUnderstood:[self getChunk]. 

    ].

    ^ nil

     RIFFReader fromFile:'/home2/pd_stuff/movies/avi/hangldm.avi'      

     RIFFReader fromFile:'/home2/cg/AFsp-V2R0/test/audiofiles/jg00b1ss.wav'      

    "Modified: 17.4.1997 / 03:25:08 / cg"

skipChunk:chunkSize

    ^ '$Header: /cvs/stx/stx/libview2/RIFFReader.st,v 1.4 2000-11-23 17:08:13 cg Exp $'