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-- This file is part of broadcaster library
-- Licensed under MIT License
-- Copyright (c) 2019 Ranx
-- https://github.com/r4nx/broadcaster
-- Version 0.2.0
local packet = {}
local utils = require 'broadcaster.utils'
local logger = require 'log'
local inspect = require 'inspect'
packet.PACKETS_ID = {
START_TRANSFER = 1,
STOP_TRANSFER = 2,
DATA = 3,
HANDLER_ID = 4
}
packet.StartTransferPacket = {}
packet.StartTransferPacket.__index = packet.StartTransferPacket
setmetatable(packet.StartTransferPacket, {
__call = function(cls, ...)
local self = setmetatable({}, cls)
self:_init(...)
return self
end
})
-- Args:
-- sessionId <number> (decimal)
function packet.StartTransferPacket:_init(sessionId)
self.sessionId = sessionId
end
function packet.StartTransferPacket:pack()
local packetId = utils.decToBin(packet.PACKETS_ID.START_TRANSFER, 3)
local sessionId = utils.decToBin(self.sessionId, 4)
return utils.padBinary(utils.tablesConcat(packetId, sessionId), -16)
end
function packet.StartTransferPacket.unpack(bin)
local packetId = utils.binToDec({unpack(bin, 1, 3)})
local sessionId = utils.binToDec({unpack(bin, 4, 7)})
return packet.StartTransferPacket(sessionId)
end
packet.StopTransferPacket = {}
packet.StopTransferPacket.__index = packet.StopTransferPacket
setmetatable(packet.StopTransferPacket, {
__call = function(cls, ...)
local self = setmetatable({}, cls)
self:_init(...)
return self
end
})
-- Args:
-- sessionId <number> (decimal)
function packet.StopTransferPacket:_init(sessionId)
self.sessionId = sessionId
end
function packet.StopTransferPacket:pack()
local packetId = utils.decToBin(packet.PACKETS_ID.STOP_TRANSFER, 3)
local sessionId = utils.decToBin(self.sessionId, 4)
return utils.padBinary(utils.tablesConcat(packetId, sessionId), -16)
end
function packet.StopTransferPacket.unpack(bin)
local packetId = utils.binToDec({unpack(bin, 1, 3)})
local sessionId = utils.binToDec({unpack(bin, 4, 7)})
return packet.StopTransferPacket(sessionId)
end
packet.DataPacket = {}
packet.DataPacket.__index = packet.DataPacket
setmetatable(packet.DataPacket, {
__call = function(cls, ...)
local self = setmetatable({}, cls)
self:_init(...)
return self
end
})
-- Args:
-- data <number> - data to transfer (1 byte in decimal number system)
-- sessionId <number> (decimal)
function packet.DataPacket:_init(data, sessionId)
if select(2, math.frexp(data)) > 8 then
error('data is too large: only 1 byte allowed')
end
self.data = data
self.sessionId = sessionId
end
function packet.DataPacket:pack()
local packetId = utils.decToBin(packet.PACKETS_ID.DATA, 3)
local sessionId = utils.decToBin(self.sessionId, 4)
local parityBit = {utils.getParity(self.data) and 1 or 0}
local data = utils.decToBin(self.data, 8)
return utils.padBinary(utils.tablesConcat(packetId, sessionId, parityBit, data), -16)
end
function packet.DataPacket.unpack(bin)
local packetId = utils.binToDec({unpack(bin, 1, 3)})
logger.debug('data packet > packet id: ' .. packetId)
local sessionId = utils.binToDec({unpack(bin, 4, 7)})
logger.debug('data packet > session id: ' .. sessionId)
local parityBit = bin[8]
logger.debug('data packet > parity bit:' .. parityBit)
local data = utils.binToDec({unpack(bin, 9, 16)})
logger.debug('data packet > data: ' .. inspect(data))
if (utils.getParity(data) and 1 or 0) ~= parityBit then
logger.warn('got parity bit: ' .. parityBit)
logger.warn('actual parity bit: ' .. (utils.getParity(data) and 1 or 0))
error('corrupted data packet: parity bits do not match')
end
return packet.DataPacket(data, sessionId)
end
packet.HandlerIdPacket = {}
packet.HandlerIdPacket.__index = packet.HandlerIdPacket
setmetatable(packet.HandlerIdPacket, {
__call = function(cls, ...)
local self = setmetatable({}, cls)
self:_init(...)
return self
end
})
-- Args:
-- handlerId <number> - handler id, decimal, 1 byte
-- sessionId <number> (decimal)
function packet.HandlerIdPacket:_init(handlerId, sessionId)
if select(2, math.frexp(handlerId)) > 8 then
error('handlerId is too large: only 1 byte allowed')
end
self.handlerId = handlerId
self.sessionId = sessionId
end
function packet.HandlerIdPacket:pack()
local packetId = utils.decToBin(packet.PACKETS_ID.HANDLER_ID, 3)
local sessionId = utils.decToBin(self.sessionId, 4)
local parityBit = {utils.getParity(self.handlerId) and 1 or 0}
local handlerId = utils.decToBin(self.handlerId, 8)
return utils.padBinary(utils.tablesConcat(packetId, sessionId, parityBit, handlerId), -16)
end
function packet.HandlerIdPacket.unpack(bin)
local packetId = utils.binToDec({unpack(bin, 1, 3)})
local sessionId = utils.binToDec({unpack(bin, 4, 7)})
local parityBit = bin[8]
local handlerId = utils.binToDec({unpack(bin, 9, 16)})
if (utils.getParity(handlerId) and 1 or 0) ~= parityBit then
logger.warn('got parity bit: ' .. parityBit)
logger.warn('actual parity bit: ' .. (utils.getParity(handlerId) and 1 or 0))
error('corrupted handler id packet: parity bits do not match')
end
return packet.HandlerIdPacket(handlerId, sessionId)
end
return packet
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