local M = {}

function M.hex(num, big)
    return string.format(big and "%02X" or "%02x", num)
end

function M.hexlify(s, big)
    local a = {}
    local format = big and "%02X" or "%02x"
    for i = 1, #s do
        a[i] = string.format(format, s[i])
    end
    return a
end

function M.unhexlify(s)
    if #s % 2 ~= 0 then
        error('unhexlify: hexstring must contain an even number of digits')
    end
    local a = {}
    for i = 1, #s, 2 do
        local byte = tonumber(s:sub(i, i+1), 16)
        if not byte then
            error(string.format("unhexlify: encountered non-hexadecimal number at position %d", i))
        end
        a[#a + 1] = byte
    end
    return a
end

function M.bin(num)
    local bin = ""
    while num > 0 do
        local rest = num % 2
        bin = tostring(rest) .. bin
        num = math.floor(num / 2)
    end
    return bin == "" and "0" or bin
end

return M