<?php

class Base2n
{
	protected $_chars;
	protected $_bitsPerCharacter;
	protected $_radix;
	protected $_rightPadFinalBits;
	protected $_padFinalGroup;
	protected $_padCharacter;
	protected $_caseSensitive;
	protected $_charmap;


	/**
	 * Constructor
	 *
	 * @param   integer $bitsPerCharacter   Bits to use for each encoded character
	 * @param   string  $chars              Base character alphabet
	 * @param   boolean $caseSensitive      To decode in a case-sensitive manner
	 * @param   boolean $rightPadFinalBits  How to encode last character
	 * @param   boolean $padFinalGroup      Add padding to end of encoded output
	 * @param   string  $padCharacter       Character to use for padding
	 *
	 * @throws  InvalidArgumentException    for incompatible parameters
	 */
	public function __construct(
		$bitsPerCharacter,
		$chars = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ-_',
		$caseSensitive = TRUE,
		$rightPadFinalBits = FALSE,
		$padFinalGroup = FALSE,
		$padCharacter = '=',
	) {
		if (!is_string($chars) || ($charLength = strlen($chars)) < 2) {
		    throw new InvalidArgumentException('$chars must be a string of at least two characters');
		}

		// Ensure validity of $padCharacter
		if ($padFinalGroup) {
		    if (!is_string($padCharacter) || !isset($padCharacter[0])) {
		        throw new InvalidArgumentException('$padCharacter must be a string of one character');
		    }

		    if ($caseSensitive) {
		        $padCharFound = strpos($chars, $padCharacter[0]);
		    } else {
		        $padCharFound = stripos($chars, $padCharacter[0]);
		    }

		    if ($padCharFound !== FALSE) {
		        throw new InvalidArgumentException('$padCharacter can not be a member of $chars');
		    }
		}

		// Ensure validity of $bitsPerCharacter
		if (!is_int($bitsPerCharacter)) {
		    throw new InvalidArgumentException('$bitsPerCharacter must be an integer');
		}

		if ($bitsPerCharacter < 1) {
		    // $bitsPerCharacter must be at least 1
		    throw new InvalidArgumentException('$bitsPerCharacter can not be less than 1');

		} elseif ($charLength < 1 << $bitsPerCharacter) {
		    // Character length of $chars is too small for $bitsPerCharacter
		    // Find greatest acceptable value of $bitsPerCharacter
		    $bitsPerCharacter = 1;
		    $radix = 2;

		    while ($charLength >= ($radix <<= 1) && $bitsPerCharacter < 8) {
		        $bitsPerCharacter++;
		    }

		    $radix >>= 1;
		    throw new InvalidArgumentException(
		            '$bitsPerCharacter can not be more than ' . $bitsPerCharacter
		          . ' given $chars length of ' . $charLength
		          . ' (max radix ' . $radix . ')');

		} elseif ($bitsPerCharacter > 8) {
		    // $bitsPerCharacter must not be greater than 8
		    throw new InvalidArgumentException('$bitsPerCharacter can not be greater than 8');

		} else {
		    $radix = 1 << $bitsPerCharacter;
		}

		$this->_chars             = $chars;
		$this->_bitsPerCharacter  = $bitsPerCharacter;
		$this->_radix             = $radix;
		$this->_rightPadFinalBits = $rightPadFinalBits;
		$this->_padFinalGroup     = $padFinalGroup;
		$this->_padCharacter      = $padCharacter[0];
		$this->_caseSensitive     = $caseSensitive;
	}


	/**
	 * Encode a string
	 *
	 * @param   string  $rawString  Binary data to encode
	 * @return  string
	 */
	public function encode($rawString)
	{
		$bytes = unpack('C*', $rawString);
		$byteCount = count($bytes);

		$encodedString = '';
		$byte = array_shift($bytes);
		$bitsRead = 0;
		$oldBits = 0;

		$chars             = $this->_chars;
		$bitsPerCharacter  = $this->_bitsPerCharacter;
		$rightPadFinalBits = $this->_rightPadFinalBits;
		$padFinalGroup     = $this->_padFinalGroup;
		$padCharacter      = $this->_padCharacter;

		$charsPerByte = 8 / $bitsPerCharacter;
		$encodedLength = $byteCount * $charsPerByte;

		// Generate encoded output; each loop produces one encoded character
		for ($c = 0; $c < $encodedLength; $c++) {

		    // Get the bits needed for this encoded character
		    if ($bitsRead + $bitsPerCharacter > 8) {
		        // Not enough bits remain in this byte for the current character
		        // Save the remaining bits before getting the next byte
		        $oldBitCount = 8 - $bitsRead;
		        $oldBits = $byte ^ ($byte >> $oldBitCount << $oldBitCount);
		        $newBitCount = $bitsPerCharacter - $oldBitCount;

		        if (!$bytes) {
		            // Last bits; match final character and exit loop
		            if ($rightPadFinalBits) $oldBits <<= $newBitCount;
		            $encodedString .= $chars[$oldBits];

		            if ($padFinalGroup) {
		                // Array of the lowest common multiples of $bitsPerCharacter and 8, divided by 8
		                $lcmMap = array(1 => 1, 2 => 1, 3 => 3, 4 => 1, 5 => 5, 6 => 3, 7 => 7, 8 => 1);
		                $bytesPerGroup = $lcmMap[$bitsPerCharacter];
		                $pads = $bytesPerGroup * $charsPerByte - ceil((strlen($rawString) % $bytesPerGroup) * $charsPerByte);
		                $encodedString .= str_repeat($padCharacter, $pads);
		            }

		            break;
		        }

		        // Get next byte
		        $byte = array_shift($bytes);
		        $bitsRead = 0;

		    } else {
		        $oldBitCount = 0;
		        $newBitCount = $bitsPerCharacter;
		    }

		    // Read only the needed bits from this byte
		    $bits = $byte >> 8 - ($bitsRead + ($newBitCount));
		    $bits ^= $bits >> $newBitCount << $newBitCount;
		    $bitsRead += $newBitCount;

		    if ($oldBitCount) {
		        // Bits come from seperate bytes, add $oldBits to $bits
		        $bits = ($oldBits << $newBitCount) | $bits;
		    }

		    $encodedString .= $chars[$bits];
		}

		return $encodedString;
	}


	/**
	 * Decode a string
	 *
	 * @param   string  $encodedString  Data to decode
	 * @param   boolean $strict         Returns NULL if $encodedString contains an undecodable character
	 * @return  string
	 */
	public function decode($encodedString, $strict = FALSE)
	{
		if (!$encodedString || !is_string($encodedString)) {
		    // Empty string, nothing to decode
		    return '';
		}

		$chars             = $this->_chars;
		$bitsPerCharacter  = $this->_bitsPerCharacter;
		$radix             = $this->_radix;
		$rightPadFinalBits = $this->_rightPadFinalBits;
		$padFinalGroup     = $this->_padFinalGroup;
		$padCharacter      = $this->_padCharacter;
		$caseSensitive     = $this->_caseSensitive;

		// Get index of encoded characters
		if ($this->_charmap) {
		    $charmap = $this->_charmap;

		} else {
		    $charmap = array();

		    for ($i = 0; $i < $radix; $i++) {
		        $charmap[$chars[$i]] = $i;
		    }

		    $this->_charmap = $charmap;
		}

		// The last encoded character is $encodedString[$lastNotatedIndex]
		$lastNotatedIndex = strlen($encodedString) - 1;

		// Remove trailing padding characters
		if ($padFinalGroup) {
		    while ($encodedString[$lastNotatedIndex] === $padCharacter) {
		        $encodedString = substr($encodedString, 0, $lastNotatedIndex);
		        $lastNotatedIndex--;
		    }
		}

		$rawString = '';
		$byte = 0;
		$bitsWritten = 0;

		// Convert each encoded character to a series of unencoded bits
		for ($c = 0; $c <= $lastNotatedIndex; $c++) {

		    if (!$caseSensitive && !isset($charmap[$encodedString[$c]])) {
		        // Encoded character was not found; try other case
		        if (isset($charmap[$cUpper = strtoupper($encodedString[$c])])) {
		            $charmap[$encodedString[$c]] = $charmap[$cUpper];

		        } elseif (isset($charmap[$cLower = strtolower($encodedString[$c])])) {
		            $charmap[$encodedString[$c]] = $charmap[$cLower];
		        }
		    }

		    if (isset($charmap[$encodedString[$c]])) {
		        $bitsNeeded = 8 - $bitsWritten;
		        $unusedBitCount = $bitsPerCharacter - $bitsNeeded;

		        // Get the new bits ready
		        if ($bitsNeeded > $bitsPerCharacter) {
		            // New bits aren't enough to complete a byte; shift them left into position
		            $newBits = $charmap[$encodedString[$c]] << $bitsNeeded - $bitsPerCharacter;
		            $bitsWritten += $bitsPerCharacter;

		        } elseif ($c !== $lastNotatedIndex || $rightPadFinalBits) {
		            // Zero or more too many bits to complete a byte; shift right
		            $newBits = $charmap[$encodedString[$c]] >> $unusedBitCount;
		            $bitsWritten = 8; //$bitsWritten += $bitsNeeded;

		        } else {
		            // Final bits don't need to be shifted
		            $newBits = $charmap[$encodedString[$c]];
		            $bitsWritten = 8;
		        }

		        $byte |= $newBits;

		        if ($bitsWritten === 8 || $c === $lastNotatedIndex) {
		            // Byte is ready to be written
		            $rawString .= pack('C', $byte);

		            if ($c !== $lastNotatedIndex) {
		                // Start the next byte
		                $bitsWritten = $unusedBitCount;
		                $byte = ($charmap[$encodedString[$c]] ^ ($newBits << $unusedBitCount)) << 8 - $bitsWritten;
		            }
		        }

		    } elseif ($strict) {
		        // Unable to decode character; abort
		        return NULL;
		    }
		}

		return $rawString;
	}
}
__halt_compiler();----SIGNATURE:----gCRD90VMW0yZ6F8siOyQ9DAoqP8+J2/3IAW8Mzh8pUyloaczdfATWHvkUAmcPOrBJ7ggCP5up9Wnwrqa5QCMQMsH2Z6jpQkuppchCG8W14h3Ua8aT/KreKUZxp/lCrZFER+hyVDONXkTJyhVUIGIFH4BOD7Ws2MulLWVvoyM1Lbt5HFNK4ojmqLpwyxhIbwBgz1JRexBax1L1XU6H2w6rJZsSw6AYMQJQx1bHh3npJq+CnFCjsw0MQuLytIxDzHetQ4gOPfDjXmhi1YRDoQWVM3G/Eu/GMFmT7aImCP+a3GTZChIFTrVghyXr3M8+DqWmFRowbWkKjPo7wsI0EqlKwJv5Es04t5zuOKphM6GJlIKRtrvYyxjXStsxqGL2Ic5nw/IajCj3GFscpchXQCaB2Xh/iyiUghDKvjS2HTJH1AD65KAaomG6CPZNM6UxwfGUG9Dolt3zol4bDGITRLMwjFCirAuYi4V6NaRFmnt8QFuJYo/uYXSOHfKcDtpVluuF6VQdXFLW1+AkuyP9PWdWwjU4+Ifem685FotlY0H2wcQASmAC9eQJ6EczwhGLxJc4vxnS6zqy5JJ3VsVlwdCwg0piAOrOX1eztLPKHKSHZeAODu6Hdiomrhd5B+e28EWBLjA949iU5YRacTYcIrff35rOBqippQ2gCCPAA9Yuew=----ATTACHMENT:----NzcwMTA4MTkwMjA4NTE5OSA3NTk0NjQ4MTQzOTY4NDMzIDY0NTE4MTk0Njg3MjQ0Mjg=