discuz和ecshop截取字符串的两个函数
discuz截取字符串是基于php没有安装mb_substr等扩展运用的，并且如果截取中文字是二个字符作为计算。而ecshop是基于php的mb_substr，iconv_substr这两个扩展来运行的，中文都是以一个字符运算。
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discuz 字符串截取
function cutstr($string, $length, $dot = ' ...') {
if(strlen($string) <= $length) {
return $string;
}
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$pre = chr(1);
$end = chr(1);
$string = str_replace(array('&', '"', '<', '>'), array($pre.'&'.$end, $pre.'"'.$end, $pre.'<'.$end, $pre.'>'.$end), $string);
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$strcut = '';
if(strtolower(CHARSET) == 'utf-8') {
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$n = $tn = $noc = 0;
while($n < strlen($string)) {
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$t = ord($string[$n]);
if($t == 9 || $t == 10 || (32 <= $t && $t <= 126)) {
$tn = 1; $n++; $noc++;
} elseif(194 <= $t && $t <= 223) {
$tn = 2; $n += 2; $noc += 2;
} elseif(224 <= $t && $t <= 239) {
$tn = 3; $n += 3; $noc += 2;
} elseif(240 <= $t && $t <= 247) {
$tn = 4; $n += 4; $noc += 2;
} elseif(248 <= $t && $t <= 251) {
$tn = 5; $n += 5; $noc += 2;
} elseif($t == 252 || $t == 253) {
$tn = 6; $n += 6; $noc += 2;
} else {
$n++;
}
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if($noc >= $length) {
break;
}
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}
if($noc > $length) {
$n -= $tn;
}
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$strcut = substr($string, 0, $n);
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} else {
for($i = 0; $i < $length; $i++) {
$strcut .= ord($string[$i]) > 127 ? $string[$i].$string[++$i] : $string[$i];
}
}
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$strcut = str_replace(array($pre.'&'.$end, $pre.'"'.$end, $pre.'<'.$end, $pre.'>'.$end), array('&', '"', '<', '>'), $strcut);
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$pos = strrpos($strcut, chr(1));
if($pos !== false) {
$strcut = substr($strcut,0,$pos);
}
return $strcut.$dot;
}
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$string = '我是中国人';
echo cutstr($string, 6, $dot = ' ...');//我是中。。。
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ecshop 字符串截取
$string = '我是中国人';
echo sub_str($string, 3);//我是中。。。
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function sub_str($str, $length = 0, $append = true)
{
?? ?$str = trim($str);
?? ?$strlength = strlen($str);
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?? ?if ($length == 0 || $length >= $strlength)
?? ?{
?? ? ? ?return $str;
?? ?}
?? ?elseif ($length < 0)
?? ?{
?? ? ? ?$length = $strlength + $length;
?? ? ? ?if ($length < 0)
?? ? ? ?{
?? ? ? ? ? ?$length = $strlength;
?? ? ? ?}
?? ?}
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?? ?if (function_exists('mb_substr'))
?? ?{
?? ? ? ?$newstr = mb_substr($str, 0, $length, 'utf-8');
?? ?}
?? ?elseif (function_exists('iconv_substr'))
?? ?{
?? ? ? ?$newstr = iconv_substr($str, 0, $length, 'utf-8');
?? ?}
?? ?else
?? ?{
?? ? ? ?//$newstr = trim_right(substr($str, 0, $length));
?? ? ? ?$newstr = substr($str, 0, $length);
?? ?}
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?? ?if ($append && $str != $newstr)
?? ?{
?? ? ? ?$newstr .= '...';
?? ?}
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?? ?return $newstr;
}