php支持gb2312,uft-8中英文字符截取函数

php教程支持gb2312,uft-8中英文字符截取函数

//截取gb2312中文字符串
function mysubstr($str, $start, $len) {
$tmps教程tr = "";
$strlen = $start + $len;
for($i = 0; $i < $strlen; $i++) {
if(ord(substr($str, $i, 1)) > 0xa0) {
$tmpstr .= substr($str, $i, 2);
$i++;
} else
$tmpstr .= substr($str, $i, 1);
}
return $tmpstr;
}
?>

//截取utf8字符串
function utf8substr($str, $from, $len)
{
return preg_replace('#^(?:[x00-x7f]|[xc0-xff][x80-xbf]+){0,'.$from.'}'.
'((?:[x00-x7f]|[xc0-xff][x80-xbf]+){0,'.$len.'}).*#s',
'$1',$str);
}
?>

把上面两个例子整合了

/*
utf-8、gb2312都支持的汉字截取函数
cut_str(字符串, 截取长度, 开始长度, 编码);
编码默认为 utf-8
开始长度默认为 0
*/

function cut_str($string, $sublen, $start = 0, $code = 'utf-8')
{
if($code == 'utf-8')
{
$pa = "/[x01-x7f]|[xc2-xdf][x80-xbf]|xe0[xa0-xbf][x80-xbf]|[xe1-xef][x80-xbf][x80-xbf]|xf0[x90-xbf][x80-xbf][x80-xbf]|[xf1-xf7][x80-xbf][x80-xbf][x80-xbf]/";
preg_match_all($pa, $string, $t_string);

if(count($t_string[0]) - $start > $sublen) return join('', array_slice($t_string[0], $start, $sublen))."...";
return join('', array_slice($t_string[0], $start, $sublen));
}
else
{
$start = $start*2;
$sublen = $sublen*2;
$strlen = strlen($string);
$tmpstr = '';

for($i=0; $i< $strlen; $i++)
{
if($i>=$start && $i< ($start+$sublen))
{
if(ord(substr($string, $i, 1))>129)
{
$tmpstr.= substr($string, $i, 2);
}
else
{
$tmpstr.= substr($string, $i, 1);
}
}
if(ord(substr($string, $i, 1))>129) $i++;
}
if(strlen($tmpstr)< $strlen ) $tmpstr.= "...";
return $tmpstr;
}
}

$str = "abcd需要截取的字符串";
echo cut_str($str, 8, 0, 'gb2312');
?>