Cyclic Redundancy Checks - Lua

-- **********************************************************************************************
--  CRC_Calculate - Calculate a 32-bit CRC based on a given polynomial and block of data.
--  This function caluclates a CRC checksum.
--  Arguments:
--  gen_poly - The generator polynomial. (MSB-0)
--  data - A table with the data to run the CRC on.
--  Returns:
--  The checksum

function calculate_CRC(gen_poly, data)
    local remainder = 0
    for i=1, #data do
        remainder = bit.bxor(remainder, bit.blshift(data[i], 24))
        for i=1, 8 do
            if (bit.band(remainder, 0x80000000) > 0) then
                remainder = bit.bxor(bit.blshift(remainder,1), gen_poly)
            else
                remainder = bit.blshift(remainder,1)
            end
        end
    end
    return remainder
end

-- **********************************************************************************************
-- intToHex() - Convert a number to a hexadecimal string
-- Arguments:
--  input - The input number
-- Returns:
--  string output
-- This function is deprecated, use string.format("%X", input) instead. (Thanks to tomass1996 for pointing this out)

function intToHex(input)
    -- local output = {}
    -- local iter = 1
    -- while true do
        -- output[iter] = input % 16
        -- input = math.floor((input - output[iter]) / 16)
        -- if(output[iter] == 10) then
            -- output[iter] = "A"
        -- elseif(output[iter] == 11) then
            -- output[iter] = "B"
        -- elseif(output[iter] == 12) then
            -- output[iter] = "C"
        -- elseif(output[iter] == 13) then
            -- output[iter] = "D"
        -- elseif(output[iter] == 14) then
            -- output[iter] = "E"
        -- elseif(output[iter] == 15) then
            -- output[iter] = "F"
        -- end
        -- if ( input == 0 ) then
            -- return table.concat(output)
        -- end
        -- iter = iter+1
    -- end
    return string.format("%X", input)
end

-- **********************************************************************************************
-- intToHex() - Convert a hexadecimal digit into a number TYPE ("string" to "number")
-- Arguments:
--  input - The input hex digit
-- Returns:
--  number output
-- This function is deprecated, use tonumber(input, 16) instead

function hexToInt(input)
    -- if (tonumber(input)) then
        -- return tonumber(input)
    -- else
        -- if(input == "a" or input == "A") then
            -- return 10
        -- elseif(input == "b" or input == "B") then
            -- return 11
        -- elseif(input == "c" or input == "C") then
            -- return 12
        -- elseif(input == "d" or input == "D") then
            -- return 13
        -- elseif(input == "e" or input == "E") then
            -- return 14
        -- elseif(input == "f" or input == "F") then
            -- return 15
        -- end
    -- end
    -- return -1
    return tonumber(input, 16)
end