--[[
    @desc: 数字转为ASCII码表示的字符串
    author:BogeyRuan
    time:2019-07-11 14:56:19
    --@num: 
    --@long: 转为多少个字节的字符，默认为动态长度
    @return:
]]
function string.numToAscii(num, long)
    local str = ""
    local asciiNum = num % 256
    while asciiNum >= 0 and num > 0 do
        str = string.char(asciiNum) .. str
        num = math.floor(num / 256)
        asciiNum = num % 256
    end
    if long then
        if #str > long then
            str = string.sub(str, -long, -1)
        else
            local dis = long - #str
            for i = 1, dis do
                str = string.char(0) .. str
            end
        end
    end

    return str
end

--[[
    @desc: ASCII码转为数字
    author:BogeyRuan
    time:2019-07-11 15:49:03
    --@str: 
    @return:
]]
function string.asciiToNum(str)
    local num = 0
    for i = 1, #str do
        local s = string.sub(str, -i, -i)
        num = num + string.byte(s) * (256 ^ (i - 1))
    end
    return num
end