| 1 |
<?php |
| 2 |
|
| 3 |
namespace WP_Defender\Extra; |
| 4 |
/** |
| 5 |
* Binary-to-text PHP Utilities |
| 6 |
* |
| 7 |
* @package binary-to-text-php |
| 8 |
* @link https://github.com/ademarre/binary-to-text-php |
| 9 |
* @author Andre DeMarre |
| 10 |
* @copyright 2009-2013 Andre DeMarre |
| 11 |
* @license http://opensource.org/licenses/MIT MIT |
| 12 |
*/ |
| 13 |
|
| 14 |
/** |
| 15 |
* Class for binary-to-text encoding with a base of 2^n |
| 16 |
* |
| 17 |
* The Base2n class is for binary-to-text conversion. It employs a |
| 18 |
* generalization of the algorithms used by many encoding schemes that |
| 19 |
* use a fixed number of bits to encode each character. In other words, |
| 20 |
* the base is a power of 2. |
| 21 |
* |
| 22 |
* Earlier versions of this class were named |
| 23 |
* FixedBitNotation and FixedBitEncoding. |
| 24 |
* |
| 25 |
* @package binary-to-text-php |
| 26 |
*/ |
| 27 |
class Base2n { |
| 28 |
protected $_chars; |
| 29 |
protected $_bitsPerCharacter; |
| 30 |
protected $_radix; |
| 31 |
protected $_rightPadFinalBits; |
| 32 |
protected $_padFinalGroup; |
| 33 |
protected $_padCharacter; |
| 34 |
protected $_caseSensitive; |
| 35 |
protected $_charmap; |
| 36 |
|
| 37 |
/** |
| 38 |
* Constructor |
| 39 |
* |
| 40 |
* @param integer $bitsPerCharacter Bits to use for each encoded character |
| 41 |
* @param string $chars Base character alphabet |
| 42 |
* @param boolean $caseSensitive To decode in a case-sensitive manner |
| 43 |
* @param boolean $rightPadFinalBits How to encode last character |
| 44 |
* @param boolean $padFinalGroup Add padding to end of encoded output |
| 45 |
* @param string $padCharacter Character to use for padding |
| 46 |
* |
| 47 |
* @throws InvalidArgumentException for incompatible parameters |
| 48 |
*/ |
| 49 |
public function __construct( |
| 50 |
$bitsPerCharacter, |
| 51 |
$chars = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ-_', |
| 52 |
$caseSensitive = true, $rightPadFinalBits = false, |
| 53 |
$padFinalGroup = false, $padCharacter = '=' |
| 54 |
) { |
| 55 |
// Ensure validity of $chars |
| 56 |
if ( ! is_string( $chars ) || ( $charLength = strlen( $chars ) ) < 2 ) { |
| 57 |
throw new InvalidArgumentException( '$chars must be a string of at least two characters' ); |
| 58 |
} |
| 59 |
|
| 60 |
// Ensure validity of $padCharacter |
| 61 |
if ( $padFinalGroup ) { |
| 62 |
if ( ! is_string( $padCharacter ) || ! isset( $padCharacter[0] ) ) { |
| 63 |
throw new InvalidArgumentException( '$padCharacter must be a string of one character' ); |
| 64 |
} |
| 65 |
|
| 66 |
if ( $caseSensitive ) { |
| 67 |
$padCharFound = strpos( $chars, $padCharacter[0] ); |
| 68 |
} else { |
| 69 |
$padCharFound = stripos( $chars, $padCharacter[0] ); |
| 70 |
} |
| 71 |
|
| 72 |
if ( $padCharFound !== false ) { |
| 73 |
throw new InvalidArgumentException( '$padCharacter can not be a member of $chars' ); |
| 74 |
} |
| 75 |
} |
| 76 |
|
| 77 |
// Ensure validity of $bitsPerCharacter |
| 78 |
if ( ! is_int( $bitsPerCharacter ) ) { |
| 79 |
throw new InvalidArgumentException( '$bitsPerCharacter must be an integer' ); |
| 80 |
} |
| 81 |
|
| 82 |
if ( $bitsPerCharacter < 1 ) { |
| 83 |
// $bitsPerCharacter must be at least 1 |
| 84 |
throw new InvalidArgumentException( '$bitsPerCharacter can not be less than 1' ); |
| 85 |
|
| 86 |
} elseif ( $charLength < 1 << $bitsPerCharacter ) { |
| 87 |
// Character length of $chars is too small for $bitsPerCharacter |
| 88 |
// Find greatest acceptable value of $bitsPerCharacter |
| 89 |
$bitsPerCharacter = 1; |
| 90 |
$radix = 2; |
| 91 |
|
| 92 |
while ( $charLength >= ( $radix <<= 1 ) && $bitsPerCharacter < 8 ) { |
| 93 |
$bitsPerCharacter ++; |
| 94 |
} |
| 95 |
|
| 96 |
$radix >>= 1; |
| 97 |
throw new InvalidArgumentException( |
| 98 |
'$bitsPerCharacter can not be more than ' . $bitsPerCharacter |
| 99 |
. ' given $chars length of ' . $charLength |
| 100 |
. ' (max radix ' . $radix . ')' ); |
| 101 |
|
| 102 |
} elseif ( $bitsPerCharacter > 8 ) { |
| 103 |
// $bitsPerCharacter must not be greater than 8 |
| 104 |
throw new InvalidArgumentException( '$bitsPerCharacter can not be greater than 8' ); |
| 105 |
|
| 106 |
} else { |
| 107 |
$radix = 1 << $bitsPerCharacter; |
| 108 |
} |
| 109 |
|
| 110 |
$this->_chars = $chars; |
| 111 |
$this->_bitsPerCharacter = $bitsPerCharacter; |
| 112 |
$this->_radix = $radix; |
| 113 |
$this->_rightPadFinalBits = $rightPadFinalBits; |
| 114 |
$this->_padFinalGroup = $padFinalGroup; |
| 115 |
$this->_padCharacter = $padCharacter[0]; |
| 116 |
$this->_caseSensitive = $caseSensitive; |
| 117 |
} |
| 118 |
|
| 119 |
/** |
| 120 |
* Encode a string |
| 121 |
* |
| 122 |
* @param string $rawString Binary data to encode |
| 123 |
* |
| 124 |
* @return string |
| 125 |
*/ |
| 126 |
public function encode( $rawString ) { |
| 127 |
// Unpack string into an array of bytes |
| 128 |
$bytes = unpack( 'C*', $rawString ); |
| 129 |
$byteCount = count( $bytes ); |
| 130 |
|
| 131 |
$encodedString = ''; |
| 132 |
$byte = array_shift( $bytes ); |
| 133 |
$bitsRead = 0; |
| 134 |
$oldBits = 0; |
| 135 |
|
| 136 |
$chars = $this->_chars; |
| 137 |
$bitsPerCharacter = $this->_bitsPerCharacter; |
| 138 |
$rightPadFinalBits = $this->_rightPadFinalBits; |
| 139 |
$padFinalGroup = $this->_padFinalGroup; |
| 140 |
$padCharacter = $this->_padCharacter; |
| 141 |
|
| 142 |
$charsPerByte = 8 / $bitsPerCharacter; |
| 143 |
$encodedLength = $byteCount * $charsPerByte; |
| 144 |
|
| 145 |
// Generate encoded output; each loop produces one encoded character |
| 146 |
for ( $c = 0; $c < $encodedLength; $c ++ ) { |
| 147 |
|
| 148 |
// Get the bits needed for this encoded character |
| 149 |
if ( $bitsRead + $bitsPerCharacter > 8 ) { |
| 150 |
// Not enough bits remain in this byte for the current character |
| 151 |
// Save the remaining bits before getting the next byte |
| 152 |
$oldBitCount = 8 - $bitsRead; |
| 153 |
$oldBits = $byte ^ ( $byte >> $oldBitCount << $oldBitCount ); |
| 154 |
$newBitCount = $bitsPerCharacter - $oldBitCount; |
| 155 |
|
| 156 |
if ( ! $bytes ) { |
| 157 |
// Last bits; match final character and exit loop |
| 158 |
if ( $rightPadFinalBits ) { |
| 159 |
$oldBits <<= $newBitCount; |
| 160 |
} |
| 161 |
$encodedString .= $chars[ $oldBits ]; |
| 162 |
|
| 163 |
if ( $padFinalGroup ) { |
| 164 |
// Array of the lowest common multiples of $bitsPerCharacter and 8, divided by 8 |
| 165 |
$lcmMap = array( 1 => 1, 2 => 1, 3 => 3, 4 => 1, 5 => 5, 6 => 3, 7 => 7, 8 => 1 ); |
| 166 |
$bytesPerGroup = $lcmMap[ $bitsPerCharacter ]; |
| 167 |
$pads = $bytesPerGroup * $charsPerByte - ceil( ( strlen( $rawString ) % $bytesPerGroup ) * $charsPerByte ); |
| 168 |
$encodedString .= str_repeat( $padCharacter, $pads ); |
| 169 |
} |
| 170 |
|
| 171 |
break; |
| 172 |
} |
| 173 |
|
| 174 |
// Get next byte |
| 175 |
$byte = array_shift( $bytes ); |
| 176 |
$bitsRead = 0; |
| 177 |
|
| 178 |
} else { |
| 179 |
$oldBitCount = 0; |
| 180 |
$newBitCount = $bitsPerCharacter; |
| 181 |
} |
| 182 |
|
| 183 |
// Read only the needed bits from this byte |
| 184 |
$bits = $byte >> 8 - ( $bitsRead + ( $newBitCount ) ); |
| 185 |
$bits ^= $bits >> $newBitCount << $newBitCount; |
| 186 |
$bitsRead += $newBitCount; |
| 187 |
|
| 188 |
if ( $oldBitCount ) { |
| 189 |
// Bits come from seperate bytes, add $oldBits to $bits |
| 190 |
$bits = ( $oldBits << $newBitCount ) | $bits; |
| 191 |
} |
| 192 |
|
| 193 |
$encodedString .= $chars[ $bits ]; |
| 194 |
} |
| 195 |
|
| 196 |
return $encodedString; |
| 197 |
} |
| 198 |
|
| 199 |
/** |
| 200 |
* Decode a string |
| 201 |
* |
| 202 |
* @param string $encodedString Data to decode |
| 203 |
* @param boolean $strict Returns NULL if $encodedString contains an undecodable character |
| 204 |
* |
| 205 |
* @return string |
| 206 |
*/ |
| 207 |
public function decode( $encodedString, $strict = false ) { |
| 208 |
if ( ! $encodedString || ! is_string( $encodedString ) ) { |
| 209 |
// Empty string, nothing to decode |
| 210 |
return ''; |
| 211 |
} |
| 212 |
|
| 213 |
$chars = $this->_chars; |
| 214 |
$bitsPerCharacter = $this->_bitsPerCharacter; |
| 215 |
$radix = $this->_radix; |
| 216 |
$rightPadFinalBits = $this->_rightPadFinalBits; |
| 217 |
$padFinalGroup = $this->_padFinalGroup; |
| 218 |
$padCharacter = $this->_padCharacter; |
| 219 |
$caseSensitive = $this->_caseSensitive; |
| 220 |
|
| 221 |
// Get index of encoded characters |
| 222 |
if ( $this->_charmap ) { |
| 223 |
$charmap = $this->_charmap; |
| 224 |
|
| 225 |
} else { |
| 226 |
$charmap = array(); |
| 227 |
|
| 228 |
for ( $i = 0; $i < $radix; $i ++ ) { |
| 229 |
$charmap[ $chars[ $i ] ] = $i; |
| 230 |
} |
| 231 |
|
| 232 |
$this->_charmap = $charmap; |
| 233 |
} |
| 234 |
|
| 235 |
// The last encoded character is $encodedString[$lastNotatedIndex] |
| 236 |
$lastNotatedIndex = strlen( $encodedString ) - 1; |
| 237 |
|
| 238 |
// Remove trailing padding characters |
| 239 |
if ( $padFinalGroup ) { |
| 240 |
while ( $encodedString[ $lastNotatedIndex ] === $padCharacter ) { |
| 241 |
$encodedString = substr( $encodedString, 0, $lastNotatedIndex ); |
| 242 |
$lastNotatedIndex --; |
| 243 |
} |
| 244 |
} |
| 245 |
|
| 246 |
$rawString = ''; |
| 247 |
$byte = 0; |
| 248 |
$bitsWritten = 0; |
| 249 |
|
| 250 |
// Convert each encoded character to a series of unencoded bits |
| 251 |
for ( $c = 0; $c <= $lastNotatedIndex; $c ++ ) { |
| 252 |
|
| 253 |
if ( ! $caseSensitive && ! isset( $charmap[ $encodedString[ $c ] ] ) ) { |
| 254 |
// Encoded character was not found; try other case |
| 255 |
if ( isset( $charmap[ $cUpper = strtoupper( $encodedString[ $c ] ) ] ) ) { |
| 256 |
$charmap[ $encodedString[ $c ] ] = $charmap[ $cUpper ]; |
| 257 |
|
| 258 |
} elseif ( isset( $charmap[ $cLower = strtolower( $encodedString[ $c ] ) ] ) ) { |
| 259 |
$charmap[ $encodedString[ $c ] ] = $charmap[ $cLower ]; |
| 260 |
} |
| 261 |
} |
| 262 |
|
| 263 |
if ( isset( $charmap[ $encodedString[ $c ] ] ) ) { |
| 264 |
$bitsNeeded = 8 - $bitsWritten; |
| 265 |
$unusedBitCount = $bitsPerCharacter - $bitsNeeded; |
| 266 |
|
| 267 |
// Get the new bits ready |
| 268 |
if ( $bitsNeeded > $bitsPerCharacter ) { |
| 269 |
// New bits aren't enough to complete a byte; shift them left into position |
| 270 |
$newBits = $charmap[ $encodedString[ $c ] ] << $bitsNeeded - $bitsPerCharacter; |
| 271 |
$bitsWritten += $bitsPerCharacter; |
| 272 |
|
| 273 |
} elseif ( $c !== $lastNotatedIndex || $rightPadFinalBits ) { |
| 274 |
// Zero or more too many bits to complete a byte; shift right |
| 275 |
$newBits = $charmap[ $encodedString[ $c ] ] >> $unusedBitCount; |
| 276 |
$bitsWritten = 8; //$bitsWritten += $bitsNeeded; |
| 277 |
|
| 278 |
} else { |
| 279 |
// Final bits don't need to be shifted |
| 280 |
$newBits = $charmap[ $encodedString[ $c ] ]; |
| 281 |
$bitsWritten = 8; |
| 282 |
} |
| 283 |
|
| 284 |
$byte |= $newBits; |
| 285 |
|
| 286 |
if ( $bitsWritten === 8 || $c === $lastNotatedIndex ) { |
| 287 |
// Byte is ready to be written |
| 288 |
$rawString .= pack( 'C', $byte ); |
| 289 |
|
| 290 |
if ( $c !== $lastNotatedIndex ) { |
| 291 |
// Start the next byte |
| 292 |
$bitsWritten = $unusedBitCount; |
| 293 |
$byte = ( $charmap[ $encodedString[ $c ] ] ^ ( $newBits << $unusedBitCount ) ) << 8 - $bitsWritten; |
| 294 |
} |
| 295 |
} |
| 296 |
|
| 297 |
} elseif ( $strict ) { |
| 298 |
// Unable to decode character; abort |
| 299 |
return null; |
| 300 |
} |
| 301 |
} |
| 302 |
|
| 303 |
return $rawString; |
| 304 |
} |
| 305 |
} |
| 306 |
|
