utils.packDsiData() not working well

[goodweather]

Hi,
when finalizing with many tests my Pro2 panel, I discovered that the utils.packDsiData() function was not working well.
I suspect that it is not made to handle data which is not a multiple of 7 but I’m not sure if this is the reason.
Anyway, to test the issue, just take a packed file, unpack it then repack it and compare the result… The last bytes are not correct…

The other function utils.unpackDsiData() works well on the other side.

Therefore, while getting a corrected PACK function, I have built one that is working.
Feel free to use 🙂

--
--	A function to pack DSI data according to description at end of Pro 2 and P12 manuals
--	Written because internal utils.packDsiData() Ctrlr function doesn't work properly.
--
--	DSI Packed Data Format
--	Data is packed in 8 byte “packets”, with the MS bit stripped from 7 parameter bytes,
--	and packed into an eighth byte, which is sent at the start of the 8 byte packet.
--
--	Example:
--
--	Input Data 					Packed MIDI data
--	1 A7 A6 A5 A4 A3 A2 A1 A0 	1 00 G7 F7 E7 D7 C7 B7 A7
--	2 B7 B6 B5 B4 B3 B2 B1 B0 	2 00 A6 A5 A4 A3 A2 A1 A0
--	3 C7 C6 C5 C4 C3 C2 C1 C0 	3 00 B6 B5 B4 B3 B2 B1 B0
--	4 D7 D6 D5 D4 D3 D2 D1 D0 	4 00 C6 C5 C4 C3 C2 C1 C0
--	5 E7 E6 E5 E4 E3 E2 E1 E0 	5 00 D6 D5 D4 D3 D2 D1 D0
--	6 F7 F6 F5 F4 F3 F2 F1 F0 	6 00 E6 E5 E4 E3 E2 E1 E0
--	7 G7 G6 G5 G4 G3 G2 G1 G0 	7 00 F6 F5 F4 F3 F2 F1 F0
--	8 00 G6 G5 G4 G3 G2 G1 G0
--
--	This explains why it takes 1171 MIDI bytes to transmit 1024 Program data bytes.
--
PackDsiData = function(mbUnpackedDsiData)

	console("*** PackDsiData function ***")

	-- Take a copy of mbUnpackedDsiData to avoid modifying it
	mbUnpacked = MemoryBlock(mbUnpackedDsiData)

	-- Check mbUnpacked size is a multiple of 7
	iSize = mbUnpacked:getSize()
	console("..Unpacked size="..tostring(iSize))
	iRemains = math.mod(iSize, 7)
	mbInit = MemoryBlock ({0x00})
	if iRemains ~= 0 then
		console("..Size to append="..tostring(7-iRemains))
		-- mbTemp=MemoryBlock(7-iRemains, true)	Doesn't work!
		mbTemp = MemoryBlock()
		for i=1,7-iRemains do
			mbTemp:append (mbInit)
		end
		mbUnpacked:append (mbTemp)
		console("..Temporary unpacked data: "..mbUnpacked:toHexString(1))
		console("..Temporary unpacked size="..tostring(mbUnpacked:getSize()))
	end
	mbPacked = MemoryBlock()
	if iRemains == 0 then
		console("..Calculated packed size="..8*math.floor(iSize/7))
		for i=1,8*math.floor(iSize/7) do
			mbPacked:append (mbInit)
		end
	else
		console("..Calculated packed size="..8*math.floor(iSize/7)+iRemains+1)
		for i=1,8*math.floor(iSize/7)+iRemains+1 do
			mbPacked:append (mbInit)
		end
	end

	k = 0
	for i=0,iSize-1,7 do
		-- Build and write the first packed byte from the bit7 of the 7 unpacked bytes
		FirstByte = 0
 		for j=0,6 do
			FirstByte = FirstByte + bit.rshift(mbUnpacked:getByte(i+j), 7) * 2^j
			-- console("..i="..i.." j="..j.." Bit="..tostring(bit.rshift(mbUnpacked:getByte(i+j), 7)))
		end
		mbPacked:setByte(k, FirstByte)
		-- Strip and write the 7 unpacked bytes
		for j=0,6 do
			k = k + 1
			mbPacked:setByte(k, bit.band(mbUnpacked:getByte(i+j), 0x7F))
		end
		k = k + 1
	end
	console("..Returned packed size="..tostring(mbPacked:getSize()))
	console("..Returned packed data: "..mbPacked:toHexString(1))
	
	return mbPacked

end

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