谁帮我补充Base64解码的那部分<?php class Base64 {
/**
* I have changed letter placement (P <=> x, S <=> 9) and the cases
* You can completely redo the mapping table
*/ private static $BinaryMap = array(
'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', // 7
'i', 'j', 'k', 'l', 'm', 'n', 'o', 'x', // 15
'q', 'r', '9', 't', 'u', 'v', 'w', 'x', // 23
'y', 'z', 'A', 'B', 'C', 'D', 'E', 'F', // 31
'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', // 39
'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', // 47
'W', 'P', 'Y', 'Z', '0', '1', '2', '3', // 55
'4', '5', '6', '7', '8', 'S', '+', '/', // 63
'=', // padding char
);
public function __construct() {}
public function base64_encode($input) {
$output = "";
$chr1 = $chr2 = $chr3 = $enc1 = $enc2 = $enc3 = $enc4 = null;
$i = 0;
// $input = self::utf8_encode($input);
while($i < strlen($input)) {
$chr1 = ord($input[$i++]);
$chr2 = ord($input[$i++]);
$chr3 = ord($input[$i++]);
$enc1 = $chr1 >> 2;
$enc2 = (($chr1 & 3) << 4) | ($chr2 >> 4);
$enc3 = (($chr2 & 15) << 2) | ($chr3 >> 6);
$enc4 = $chr3 & 63;
if (is_nan($chr2)) {
$enc3 = $enc4 = 64;
} else if (is_nan($chr3)) {
$enc4 = 64;
}
$output .= self::$BinaryMap[$enc1]
. self::$BinaryMap[$enc2]
. self::$BinaryMap[$enc3]
. self::$BinaryMap[$enc4];
}
return $output;
}
public function utf8_encode($input) {
$utftext = null;
for ($n = 0; $n < strlen($input); $n++) { $c = ord($input[$n]);
if ($c < 128) {
$utftext .= chr($c);
} else if (($c > 128) && ($c < 2048)) {
$utftext .= chr(($c >> 6) | 192);
$utftext .= chr(($c & 63) | 128);
} else {
$utftext .= chr(($c >> 12) | 224);
$utftext .= chr((($c & 6) & 63) | 128);
$utftext .= chr(($c & 63) | 128);
}
}
return $utftext;
}
}?>
/**
* I have changed letter placement (P <=> x, S <=> 9) and the cases
* You can completely redo the mapping table
*/ private static $BinaryMap = array(
'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', // 7
'i', 'j', 'k', 'l', 'm', 'n', 'o', 'x', // 15
'q', 'r', '9', 't', 'u', 'v', 'w', 'x', // 23
'y', 'z', 'A', 'B', 'C', 'D', 'E', 'F', // 31
'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', // 39
'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', // 47
'W', 'P', 'Y', 'Z', '0', '1', '2', '3', // 55
'4', '5', '6', '7', '8', 'S', '+', '/', // 63
'=', // padding char
);
public function __construct() {}
public function base64_encode($input) {
$output = "";
$chr1 = $chr2 = $chr3 = $enc1 = $enc2 = $enc3 = $enc4 = null;
$i = 0;
// $input = self::utf8_encode($input);
while($i < strlen($input)) {
$chr1 = ord($input[$i++]);
$chr2 = ord($input[$i++]);
$chr3 = ord($input[$i++]);
$enc1 = $chr1 >> 2;
$enc2 = (($chr1 & 3) << 4) | ($chr2 >> 4);
$enc3 = (($chr2 & 15) << 2) | ($chr3 >> 6);
$enc4 = $chr3 & 63;
if (is_nan($chr2)) {
$enc3 = $enc4 = 64;
} else if (is_nan($chr3)) {
$enc4 = 64;
}
$output .= self::$BinaryMap[$enc1]
. self::$BinaryMap[$enc2]
. self::$BinaryMap[$enc3]
. self::$BinaryMap[$enc4];
}
return $output;
}
public function utf8_encode($input) {
$utftext = null;
for ($n = 0; $n < strlen($input); $n++) { $c = ord($input[$n]);
if ($c < 128) {
$utftext .= chr($c);
} else if (($c > 128) && ($c < 2048)) {
$utftext .= chr(($c >> 6) | 192);
$utftext .= chr(($c & 63) | 128);
} else {
$utftext .= chr(($c >> 12) | 224);
$utftext .= chr((($c & 6) & 63) | 128);
$utftext .= chr(($c & 63) | 128);
}
}
return $utftext;
}
}?>
这段代码在运行效率和内存占用上比起内置的API要差不少呢