php 中文和编码判断代码

编码范围1. gbk (gb2312/gb18030)
\x00-\xff gbk双字节编码范围
\x20-\x7f ascii
\xa1-\xff 中文
\x80-\xff 中文
2. utf-8 (unicode)
\u4e00-\u9fa5 (中文)
\x3130-\x318f (韩文
\xac00-\xd7a3 (韩文)
\u0800-\u4e00 (日文)
ps: 韩文是大于[\u9fa5]的字符
正则例子:
preg_replace(”/([\x80-\xff])/”,”",$str);
preg_replace(”/([u4e00-u9fa5])/”,”",$str);
二、代码例子

//判断内容里有没有中文-gbk (php)
function check_is_chinese($s){
return preg_match('/[\x80-\xff]./', $s);
}
//获取字符串长度-gbk (php)
function gb_strlen($str){
$count = 0;
for($i=0; $i<strlen($str); $i++){
$s = substr($str, $i, 1);
if (preg_match("/[\x80-\xff]/", $s)) ++$i;
++$count;
}
return $count;
}
//截取字符串字串-gbk (php)
function gb_substr($str, $len){
$count = 0;
for($i=0; $i<strlen($str); $i++){
if($count == $len) break;
if(preg_match("/[\x80-\xff]/", substr($str, $i, 1))) ++$i;
++$count;
}
return substr($str, 0, $i);
}
//统计字符串长度-utf8 (php)
function utf8_strlen($str) {
$count = 0;
for($i = 0; $i < strlen($str); $i++){
$value = ord($str[$i]);
if($value > 127) {
$count++;
if($value >= 192 && $value <= 223) $i++;
elseif($value >= 224 && $value <= 239) $i = $i + 2;
elseif($value >= 240 && $value <= 247) $i = $i + 3;
else die('not a utf-8 compatible string');
}
$count++;
}
return $count;
}
//截取字符串-utf8(php)
function utf8_substr($str,$position,$length){
$start_position = strlen($str);
$start_byte = 0;
$end_position = strlen($str);
$count = 0;
for($i = 0; $i < strlen($str); $i++){
if($count >= $position && $start_position > $i){
$start_position = $i;
$start_byte = $count;
}
if(($count-$start_byte)>=$length) {
$end_position = $i;
break;
}
$value = ord($str[$i]);
if($value > 127){
$count++;
if($value >= 192 && $value <= 223) $i++;
elseif($value >= 224 && $value <= 239) $i = $i + 2;
elseif($value >= 240 && $value <= 247) $i = $i + 3;
else die('not a utf-8 compatible string');
}
$count++;
}
return(substr($str,$start_position,$end_position-$start_position));
}
//判断是否是有韩文-utf-8 (javascript)
function checkkoreachar(str) {
for(i=0; i<str.length; i++) {
if(((str.charcodeat(i) > 0x3130 && str.charcodeat(i) < 0x318f) || (str.charcodeat(i) >= 0xac00 && str.charcodeat(i) <= 0xd7a3))) {
return true;
}
}
return false;
}
//判断是否有中文字符-gbk (javascript)
function check_chinese_char(s){
return (s.length != s.replace(/[^\x00-\xff]/g,"**").length);
}