PHP的ASCII码转换类

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; }