PHPASCII码转换操作类

PHP ASCII码转换类可以把中文转ascii码。并且可以批量转换，还增加了一个常用的ascii代码还原字符。

具体代码如下：

class ascii
{
 
function decode($str)
{
    preg_match_all( "/(d{2,5})/", $str,$a);
    $a = $a[0];
    foreach ($a as $dec)
    {
        if ($dec < 128)
        {
            $utf .= chr($dec);
        }
        else if ($dec < 2048)
       {
            $utf .= chr(192 + (($dec - ($dec % 64)) / 64));
            $utf .= chr(128 + ($dec % 64));
        }
        else
        {
            $utf .= chr(224 + (($dec - ($dec % 4096)) / 4096)); 
            $utf .= chr(128 + ((($dec % 4096) - ($dec % 64)) / 64)); 
            $utf .= chr(128 + ($dec % 64)); 
        } 
    } 
    return $utf; 
}
 
function encode($c)
{ 
    $len = strlen($c); 
    $a = 0; 
    while ($a < $len)
    {
        $ud = 0; 
        if (ord($c{$a}) >=0 && ord($c{$a})<=127)
        {
            $ud = ord($c{$a}); 
            $a += 1; 
        }
        else if (ord($c{$a}) >=192 && ord($c{$a})<=223)
        {
            $ud = (ord($c{$a})-192)*64 + (ord($c{$a+1})-128); 
            $a += 2; 
        }
        else if (ord($c{$a}) >=224 && ord($c{$a})<=239)
        {
            $ud = (ord($c{$a})-224)*4096 + (ord($c{$a+1})-128)*64 + (ord($c{$a+2})-128); 
            $a += 3; 
        }
        else if (ord($c{$a}) >=240 && ord($c{$a})<=247)
        {
            $ud = (ord($c{$a})-240)*262144 + (ord($c{$a+1})-128)*4096 + (ord($c{$a+2})-128)*64 + (ord($c{$a+3})-128); 
            $a += 4; 
        }
        else if (ord($c{$a}) >=248 && ord($c{$a})<=251)
        {
            $ud = (ord($c{$a})-248)*16777216 + (ord($c{$a+1})-128)*262144 + (ord($c{$a+2})-128)*4096 + (ord($c{$a+3})-128)*64 + (ord($c{$a+4})-128);
            $a += 5; 
        }
        else if (ord($c{$a}) >=252 && ord($c{$a})<=253)
        {
            $ud = (ord($c{$a})-252)*1073741824 + (ord($c{$a+1})-128)*16777216 + (ord($c{$a+2})-128)*262144 + (ord($c{$a+3})-128)*4096 + (ord($c{$a+4})-128)*64 + (ord($c{$a+5})-128); 
            $a += 6; 
        }
        else if (ord($c{$a}) >=254 && ord($c{$a})<=255)
        { //error
            $ud = false; 
        } 
        $scill .= "&#$ud;";
    } 
    return $scill; 
}
 
}
?>