45 lines
1.2 KiB
Lua
45 lines
1.2 KiB
Lua
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local imt = {}
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function imt.to16bn(n)
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return string.char(math.floor(n/256))..string.char(math.floor(n%256))
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end
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function imt.from16bn(s)
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return (string.byte(s,1,1)*256)+string.byte(s,2,2)
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end
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function imt.encodePacket(packetID, packetType, destination, sender, port, data)
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local rs = string.char(packetID:len()%256)..packetID..string.char(packetType)
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rs=rs..string.char(destination:len()%256)..destination
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rs=rs..string.char(sender:len()%256)..sender
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rs=rs..to16bn(port)
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rs=rs..to16bn(data:len())..data
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return rs
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end
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function imt.decodePacket(s)
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local pidlen, destlen, senderlen, datalen, packetID, packetType, destination, sender, port, data
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pidlen = string.byte(s:sub(1,1))
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s=s:sub(2)
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packetID = s:sub(1,pidlen)
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s=s:sub(pidlen+1)
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packetType = string.byte(s:sub(pidlen+1))
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s=s:sub(2)
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destlen = string.byte(s:sub(1,1))
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s=s:sub(2)
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destination = s:sub(1,destlen)
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s=s:sub(destlen+1)
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senderlen=string.byte(s:sub(1,1))
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s=s:sub(2)
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sender = s:sub(1,senderlen)
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s=s:sub(senderlen+1)
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port=from16bn(s:sub(1,2))
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s=s:sub(3)
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datalen=from16bn(s:sub(1,2))
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s=s:sub(3)
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data=s:sub(1,datalen)
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s=s:sub(datalen+1)
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return packetID, packetType, destination, sender, port, data, s
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end
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return imt
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