php实现gbk和uft8编码中英文字符截取函数的应用

php实现gbk和uft8编码中英文字符截取函数的应用

<?php

//截取gb2312中文字符串

function mysubstr($str, $start, $len) {

$tmpstr = "";

$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;

}

?>

<?php

//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

<?php

/*

utf-8、gb2312都支持的汉字截取函数

cut_str(www.3ppt.com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');

?>