php实现encode64编码类实例_PHP教程

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//encode64编码可以同时取代encodeURI,encodeURIComponent,endode函数

//因为选取的这些字符都不会被编码.

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) {

//正确的字节数肯定是余2或3, 没有1的情况, 如果出现, 舍弃.

$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;

}

?>