php截取html字符串及自动补全html标签的方法

/**
?* 截取HTML,并自动补全闭合
?* @param $html
?* @param $length
?* @param $end
?*/
function subHtml($html,$length) {
?$result = '';
?$tagStack = array();
?$len = 0;
?
?$contents = preg_split("~(<[^>]+?>)~si",$html,-1,PREG_SPLIT_NO_EMPTY| PREG_SPLIT_DELIM_CAPTURE);
?foreach($contents as $tag)
?{
?if (trim($tag)=="")? continue;
?if(preg_match("~<([a-z0-9]+)[^/>]*?/>~si",$tag)){
?$result .= $tag;
?}else if(preg_match("~</([a-z0-9]+)[^/>]*?>~si",$tag,$match)){
?if($tagStack[count($tagStack)-1] == $match[1]){
?array_pop($tagStack);
?$result .= $tag;
?}
?}else if(preg_match("~<([a-z0-9]+)[^/>]*?>~si",$match)){
?array_push($tagStack,$match[1]);
?$result .= $tag;
?}else if(preg_match("~<!--.*?-->~si",$tag)){
?$result .= $tag;
?}else{
?if($len + mstrlen($tag) < $length){
?$result .= $tag;
?$len += mstrlen($tag);?
?}else {
?$str = msubstr($tag,$length-$len+1);
?$result .= $str;
?break;
?}
?
?}
?}
?while(!emptyempty($tagStack)){
?$result .= '</'.array_pop($tagStack).'>';
?}
?return? $result;
}
?
/**
?* 截取中文字符串
?* @param $string 字符串
?* @param $start 起始位
?* @param $length 长度
?* @param $charset? 编码
?* @param $dot 附加字串
?*/
function msubstr($string,$start,$length,$dot='',$charset = 'UTF-8') {
?$string = str_replace(array('&','"','<','>','?'),array('&',' '),$string);
?if(strlen($string) <= $length) {
?return $string;
?}
?
?if(strtolower($charset) == 'utf-8') {
?$n = $tn = $noc = 0;
?while($n < strlen($string)) {
?$t = ord($string[$n]);
?if($t == 9 || $t == 10 || (32 <= $t && $t <= 126)) {
?$tn = 1; $n++;
?} elseif(194 <= $t && $t <= 223) {
?$tn = 2; $n += 2;
?} elseif(224 <= $t && $t <= 239) {
?$tn = 3; $n += 3;
?} elseif(240 <= $t && $t <= 247) {
?$tn = 4; $n += 4;
?} elseif(248 <= $t && $t <= 251) {
?$tn = 5; $n += 5;
?} elseif($t == 252 || $t == 253) {
?$tn = 6; $n += 6;
?} else {
?$n++;
?}
?$noc++;
?if($noc >= $length) {
?break;
?}
?}
?if($noc > $length) {
?$n -= $tn;
?}
?$strcut = substr($string,$n);
?} else {
?for($i = 0; $i < $length; $i++) {
?$strcut .= ord($string[$i]) > 127 ? $string[$i].$string[++$i] : $string[$i];
?}
?}
?
?return $strcut.$dot;
}
?
/**
?* 取得字符串的长度,包括中英文.
?*/
function mstrlen($str,$charset = 'UTF-8'){
?if (function_exists('mb_substr')) {
?$length=mb_strlen($str,$charset);
?} elseif (function_exists('iconv_substr')) {
?$length=iconv_strlen($str,$charset);
?} else {
?preg_match_all("/[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]/",$text,$ar);??
?$length=count($ar[0]);
?}
?return $length;
}

* @param 要截取的HTML $str
* @param 截取的数量 $num
* @param 是否需要加上更多 $more
* @return 截取串
*/
function phpos_chsubstr_ahtml($str,$num,$more=false)
{
??? $leng=strlen($str);
????? if($num>=$leng)
????? return $str;
??? $word=0;
??? $i=0;??????????????????????? /** 字符串指针 **/
??? $stag=array(array());??????? /** 存放开始HTML的标志 **/
??? $etag=array(array());??????? /** 存放结束HTML的标志 **/
??? $sp = 0;
??? $ep = 0;
????? while($word!=$num)
????? {
????????? if(ord($str[$i])>128)
????????? {
??????????? //$re.=substr($str,$i,3);
??????????? $i+=3;
??????????? $word++;
????????? }
????????? else if ($str[$i]=='<')
????????? {
????????????? if ($str[$i+1] == '!')
????????????? {
??????????????? $i++;
????????????????? continue;
????????????? }
?
????????????? if ($str[$i+1]=='/')????
????????????? {
??????????????? $ptag=&$etag ;
??????????????? $k=&$ep;
??????????????? $i+=2;
????????????? }
????????????? else????????????????????
????????????? {
??????????????? $ptag=&$stag;
??????????????? $i+=1;
??????????????? $k=&$sp;
????????????? }
?
????????????? for(;$i<$leng;$i++)????????
????????????? {
????????????????? if ($str[$i] == ' ')
????????????????? {
??????????????????? $ptag[$k] = implode('',$ptag[$k]);
??????????????????? $k++;
????????????????????? break;
????????????????? }
????????????????? if ($str[$i] != '>')?
????????????????? {
??????????????????? $ptag[$k][]=$str[$i];
????????????????????? continue;
????????????????? }
????????????????? else????????????????
????????????????? {
??????????????????? $ptag[$k] = implode('',$ptag[$k]);
??????????????????? $k++;
????????????????????? break;
????????????????? }
????????????? }
??????????? $i++;
????????????? continue;
????????? }
????????? else
????????? {
??????????? //$re.=substr($str,1);
??????????? $word++;
??????????? $i++;
????????? }
????? }
????? foreach ($etag as $val)
????? {
??????? $key1=array_search($val,$stag);
????????? if ($key1 !== false)????????? unset($stag[$key]);
????? }
????? foreach ($stag as $key => $val)
????? {
????????? if (in_array($val,array('br','img'))) unset($stag[$key1]);
????? }
??? array_reverse($stag);
??? $ends = '</'.implode('></',$stag).'>';
??? $re = substr($str,$i).$ends;
????? if($more)??? $re.='...';
????? return $re;
}

function text_zhaiyao($text,$length){ //文章摘要生成函数? $test:内容 $length:摘要长度
??? global $Briefing_Length;
??? mb_regex_encoding("UTF-8");
??? if(mb_strlen($text) <= $length ) return $text;
??? $Foremost = mb_substr($text,$length);
??? $re = "<(/?)
??? (P|DIV|H1|H2|H3|H4|H5|H6|ADDRESS|PRE|TABLE|TR|TD|TH|INPUT|SELECT|TEXTAREA|OBJECT|A|UL|OL|LI|
??? BASE|META|LINK|HR|BR|PARAM|IMG|AREA|INPUT|SPAN)[^>]*(>?)";
??? $Single = "/BASE|META|LINK|HR|BR|PARAM|IMG|AREA|INPUT|BR/i";
?????
??? $Stack = array(); $posStack = array();
?????
??? mb_ereg_search_init($Foremost,$re,'i');
?????
??? while($pos = mb_ereg_search_pos()){
??? $match = mb_ereg_search_getregs();
??? /* [Child-matching Formulation]:
?????
??? $matche[1] : A "/" charactor indicating whether current "<...>" Friction is
??? Closing Part
??? $matche[2] : Element Name.
??? $matche[3] : Right > of a "<...>" Friction
??? */
??? if($match[1]==""){
??? $Elem = $match[2];
??? if(mb_eregi($Single,$Elem) && $match[3] !=""){
??? continue;
}