require("ZZBase64")

local files

local file = io.open("E:\\2342.jpg","rb")

if file then

    print "发现文件"

    files = file:read("*a")

    file:close()

else

    print "没有找到文件"

end

--图片转成base64文本

print(ZZBase64.encode(files))

ZZBase64 = {}

local string = string

ZZBase64.__code = {

    'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',

    'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f',

    'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v',

    'w', 'x', 'y', 'z', '', '', '', '', '', '', '', '', '', '', '+', '/',

};

ZZBase64.__decode = {}

for k,v in pairs(ZZBase64.__code) do

    ZZBase64.__decode[string.byte(v,)] = k -

end

function ZZBase64.encode(text)

    local len = string.len(text)

    local left = len %

    len = len - left

    local res = {}

    local index  =

    for i = , len,  do

        local a = string.byte(text, i )

        local b = string.byte(text, i + )

        local c = string.byte(text, i + )

        -- num = a<<16 + b<<8 + c

        local num = a *  + b *  + c

        for j = ,  do

            --tmp = num >> ((4 -j) * 6)

            local tmp = math.floor(num / ( ^ ((-j) * )))

            --curPos = tmp&0x3f

            local curPos = tmp %  +

            res[index] = ZZBase64.__code[curPos]

            index = index +

        end

    end

    if left ==  then

        ZZBase64.__left1(res, index, text, len)

    elseif left ==  then

        ZZBase64.__left2(res, index, text, len)

    end

    return table.concat(res)

end

function ZZBase64.__left2(res, index, text, len)

    local num1 = string.byte(text, len + )

    num1 = num1 *  --lshift 10

    local num2 = string.byte(text, len + )

    num2 = num2 *  --lshift 2

    local num = num1 + num2

    local tmp1 = math.floor(num / ) --rShift 12

    local curPos = tmp1 %  +

    res[index] = ZZBase64.__code[curPos]

    local tmp2 = math.floor(num / )

    curPos = tmp2 %  +

    res[index + ] = ZZBase64.__code[curPos]

    curPos = num %  +

    res[index + ] = ZZBase64.__code[curPos]

    res[index + ] = "="

end

function ZZBase64.__left1(res, index,text, len)

    local num = string.byte(text, len + )

    num = num * 

    tmp = math.floor(num / )

    local curPos = tmp %  +

    res[index ] = ZZBase64.__code[curPos]

    curPos = num %  +

    res[index + ] = ZZBase64.__code[curPos]

    res[index + ] = "="

    res[index + ] = "="

end

function ZZBase64.decode(text)

    local len = string.len(text)

    local left =

    if string.sub(text, len - ) == "==" then

        left =

        len = len -

    elseif string.sub(text, len) == "=" then

        left =

        len = len -

    end

    local res = {}

    local index =

    local decode = ZZBase64.__decode

    for i =, len,  do

        local a = decode[string.byte(text,i    )]

        local b = decode[string.byte(text,i + )]

        local c = decode[string.byte(text,i + )]

        local d = decode[string.byte(text,i + )]

        --num = a<<18 + b<<12 + c<<6 + d

        local num = a *  + b *  + c *  + d

        local e = string.char(num % )

        num = math.floor(num / )

        local f = string.char(num % )

        num = math.floor(num / )

        res[index ] = string.char(num % )

        res[index + ] = f

        res[index + ] = e

        index = index +

    end

    if left ==  then

        ZZBase64.__decodeLeft1(res, index, text, len)

    elseif left ==  then

        ZZBase64.__decodeLeft2(res, index, text, len)

    end

    return table.concat(res)

end

function ZZBase64.__decodeLeft1(res, index, text, len)

    local decode = ZZBase64.__decode

    local a = decode[string.byte(text, len + )]

    local b = decode[string.byte(text, len + )]

    local c = decode[string.byte(text, len + )]

    local num = a *  + b *  + c

    local num1 = math.floor(num / ) %

    local num2 = math.floor(num / ) %

    res[index] = string.char(num1)

    res[index + ] = string.char(num2)

end

function ZZBase64.__decodeLeft2(res, index, text, len)

    local decode = ZZBase64.__decode

    local a = decode[string.byte(text, len + )]

    local b = decode[string.byte(text, len + )]

    local num = a *  + b

    num = math.floor(num / )

    res[index] = string.char(num)

end