Type RIFF_header
	filesize As ULong
	fmtlen As ULong
	fmttag As UShort
	channels As UShort
	samplerate As ULong
	bytespersecond As ULong
	frame As UShort
	bitspersample As UShort
	datalen As ULong
	headerlen As UShort
End Type

Declare Function GetRIFFval(header As String) As RIFF_header
Declare Function SetRIFFheader(header As String, parameter As RIFF_header) As String
Declare Sub showRIFFval(parameter As RIFF_header)

Function GetRIFFval(header As String) As RIFF_header
	Dim As Integer fmtpointer, datapointer
	Dim As RIFF_header rh
	Dim As Any Ptr hp
	
	fmtpointer = InStr(header,"fmt ")
	datapointer = InStr(header,"data")
	hp = StrPtr(header)
		
	With rh
		.filesize = *Cast(ULong Ptr,hp + 4)
		.fmtlen = *Cast(ULong Ptr,hp + fmtpointer + 3)
		.fmttag = *Cast(UShort Ptr,hp + fmtpointer + 7)
		.channels = *Cast(UShort Ptr,hp + fmtpointer + 9)
		.samplerate = *Cast(ULong Ptr,hp + fmtpointer + 11)
		.bytespersecond = *Cast(ULong Ptr,hp + fmtpointer + 15)
		.frame = *Cast(UShort Ptr,hp + fmtpointer + 19)
		.bitspersample = *Cast(UShort Ptr,hp + fmtpointer + 21)
		.datalen = *Cast(ULong Ptr,hp + datapointer + 3)
		.headerlen = datapointer + 7
	End With
		
	Return rh
	
End Function

Function SetRIFFheader(header As String = "", parameter As RIFF_header) As String
	Dim As Integer fmtpointer, datapointer
	Dim As String hd
	Dim As Any Ptr hp = StrPtr(header)
	
	If header = "" Then 'header erstellen
		hd = "RIFF" + Mki(0) + "WAVEfmt " + Mki(16) + String(16,Chr(0)) + "data" + Mki(0) 'dummyheader
		parameter.fmtlen = 16
	Else
		hd = header
	EndIf
	
	fmtpointer = InStr(hd,"fmt ")
	datapointer = InStr(hd,"data")
	hd = Left(hd, datapointer + 7)
	
	With parameter
	  If .filesize Then
	  	*Cast(ULong Ptr,hp + 4) = .filesize
	  EndIf
		If .fmtlen Then
			*Cast(ULong Ptr,hp + fmtpointer + 3) = .fmtlen
		EndIf
		If .fmttag Then
			*Cast(UShort Ptr,hp + fmtpointer + 7) = .fmttag
		EndIf
		If .channels Then
			*Cast(UShort Ptr,hp + fmtpointer + 9) = .channels
		EndIf
		If .samplerate Then
			*Cast(ULong Ptr,hp + fmtpointer + 11) = .samplerate
		EndIf
		If .bytespersecond Then
			*Cast(ULong Ptr,hp + fmtpointer + 15) = .bytespersecond
		EndIf
		If .frame Then 'Frame-Größe = <Anzahl der Kanäle> · ((<Bits/Sample (eines Kanals)> + 7) / 8)   (Division ohne Rest)
			*Cast(UShort Ptr,hp + fmtpointer + 19) = .frame
		EndIf
		If .bitspersample Then
			*Cast(UShort Ptr,hp + fmtpointer + 21) = .bitspersample
		EndIf
		If .datalen Then
			*Cast(ULong Ptr,hp + datapointer + 3) = .datalen
		EndIf
	End With
	
	Return hd
End Function

Sub showRIFFval(parameter As RIFF_header)
	
	With parameter
		Print "      .filesize ";.filesize;" (";.filesize + 8;")"
		Print "        .fmtlen ";.fmtlen 
		Print "        .fmttag ";.fmttag 
		Print "      .channels ";.channels
		Print "    .samplerate ";.samplerate
		Print ".bytespersecond ";.bytespersecond
		Print "         .frame ";.frame
		Print " .bitspersample ";.bitspersample 
		Print "       .datalen ";.datalen
		Print "     .headerlen ";.headerlen
	End With
	
End Sub