PHP's encode64 encoding class

encode64 can obtain the shortest data encoded by 26 English uppercase and lowercase letters and numbers plus the two symbols "-_". This string can be transmitted freely on the network without considering the confusion caused by automatic transcoding. Disadvantages: For Large strings are too slow. The reason is unknown. Maybe the PHP script itself is slow, so it has many built-in functions. If these functions are implemented in scripts, it would be intolerable. JavaScript does not have this problem, and scripts are much faster.

//encode64 encoding can replace the encodeURI, encodeURIComponent, and endode functions at the same time, because the selected characters will not be encoded.
class Encode64{
 function code($str) {
 $KEY = ' PaAwO65goUf7IK2vi9-xq8cFTEXLCDY1Hd3tV0ryzjbpN_BlnSs4mGRkQWMZJeuh';
 $a = StrToBytes($str);
 $len = count($a);
 $res = $len % 3;
 $s = "";$i = 2;$v = 0 ;
 for (; $i < $len; $i += 3) {
 $v = $a[$i - 2] + ($a[$i - 1] << 8) + ($ a[$i] << 16);
 $s .= $KEY[$v & 0x3f];
 $s .= $KEY[($v >> 6) & 0x3f];
 $s .= $KEY[($v >> 12) & 0x3f];
 $s .= $KEY[($v >> 18)];
 }
 if ($res == 1) {
 $v = $a[$i - 2];
 $s .= $KEY[$v & 0x3f];
 $s .= $KEY[($v >> 6) & 0x3f];
 } else if ($res == 2) {
 $v = $a[$i - 2] + ($a[$i - 1] << 8);
 $s .= $KEY[$v & 0x3f ];
 $s .= $KEY[($v >> 6) & 0x3f];
 $s .= $KEY[($v >> 12) & 0x3f];
 }
 return $s ;
 }
 function decode($codeStr) {
 $KEY = 'PaAwO65goUf7IK2vi9-xq8cFTEXLCDY1Hd3tV0ryzjbpN_BlnSs4mGRkQWMZJeuh';
 $dic = array();
 for ($i = 0; $i < 64; $i++) {
 $dic [$KEY[$i]] = $i;
 }
 $len = strlen($codeStr);
 $res = $len % 4;
 $cLen = floor($len/4)*3;
 if( $res==2) $clen += 1;
 elseif($res==3) $clen += 2;
 $code = range(0,$clen);
 $i = 3;$v = 0; $j = 0;
 for (; $i < $len; $i += 4) {
 $v = $dic[$codeStr[$i - 3]];
 $v += $dic[$codeStr [$i - 2]] << 6;
 $v += $dic[$codeStr[$i - 1]] << 12;
 $v += $dic[$codeStr[$i] ] << 18;
 $code[$j] = $v & 0xff;
 $code[$j+1] = ($v >> 8) & 0xff;
 $code[$j+2 ] = ($v >> 16) & 0xff;
 $j += 3;
 }
 if ($res == 2) {//The correct number of bytes must be 2 or 3, not 1 situation, if it occurs, discard it.
 $v = $dic[$codeStr[$i - 3]];
 $v += $dic[$codeStr[$i - 2]] << 6;
 $code [$j] = $v & 0xff;
 } else if ($res == 3) {
 $v = $dic[$codeStr[$i - 3]];
 $v += $dic[$codeStr[ $i - 2]] << 6;
 $v += $dic[$codeStr[$i - 1]] << 12;
 $code[$j] = $v & 0xff;
 $ code[$j+1] = ($v >> 8) & 0xff;
 }
 return BytesToStr($code);
 }
}
function BytesToStr($bytes) {
 $str = '';
 foreach($bytes as $ch) {
 $str .= chr($ch);
 }
 return iconv('UTF-16BE','utf-8',$str);
}
function StrToBytes($str ) {
 $str = iconv('utf-8','UTF-16BE',$str);
 $len = strlen($str);
 $bytes = array();
 for($i=0; $i<$len;$i++) {
 $bytes[] = ord($str[$i]) ;
 }
 return $bytes;
}
?>

php