php 擷取漢字字串 亂碼解決 支援utf8和gb2312的編碼的漢字

function gb_substr($string, $start ,$sublen, $code = 'UTF-8')
{
if($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; $i {
if($i>=$start && $i {
if(ord(substr($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) return $tmpstr;
}
}

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