Cocos2d-x Lua：获取文件大小的函数实现

返回指定文件的大小，如果失败返回 false

-- @function [parent=#io] filesize
-- @param string path 文件完全路径
-- @return integer#integer

function io.filesize(path)
    local size = false
    local file = io.open(path, "r")
    if file then
        local current = file:seek()
        size = file:seek("end")
        file:seek("set", current)
        io.close(file)
    end
    return size
end