-- lua-cjson's  is_array by Mark Pulford
function auIsArray(table)
    local max = 0
    local count = 0

    if (type(table) ~= "table") then
        return false
    end

    for k, v in pairs(table) do
        if type(k) == "number" then
            if k > max then max = k end
            count = count + 1
        else
            return false
        end
    end
    if max > count * 2 then
        return false
    end

    return max > 0
end