--计算有效字符的长度
function check_valid_char_length(str)
local bytes = {string.byte(str, 1, #str)}
local length, begin = 0, false
for _, byte in ipairs(bytes) do
if byte < 128 or byte >= 192 then--处理汉字
begin = false
length = length + 1
elseif not begin then
begin = true
length = length + 1
end
end
return length
end
