Project import generated by Copybara.
GitOrigin-RevId: 63746295f1a5ab5a619056791995793d65529e62
diff --git a/src/lib/GoogleAuthenticator/FixedByteNotation.php b/src/lib/GoogleAuthenticator/FixedByteNotation.php
new file mode 100644
index 0000000..97d22f7
--- /dev/null
+++ b/src/lib/GoogleAuthenticator/FixedByteNotation.php
@@ -0,0 +1,276 @@
+<?php
+
+/**
+* FixedBitNotation
+*
+* @author Andre DeMarre
+* @package FixedBitNotation
+*/
+
+/**
+* The FixedBitNotation class is for binary to text conversion. It
+* can handle many encoding schemes, formally defined or not, that
+* use a fixed number of bits to encode each character.
+*
+* @package FixedBitNotation
+*/
+class FixedBitNotation
+{
+ protected $_chars;
+ protected $_bitsPerCharacter;
+ protected $_radix;
+ protected $_rightPadFinalBits;
+ protected $_padFinalGroup;
+ protected $_padCharacter;
+ protected $_charmap;
+
+ /**
+ * Constructor
+ *
+ * @param integer $bitsPerCharacter Bits to use for each encoded
+ * character
+ * @param string $chars Base character alphabet
+ * @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
+ */
+ public function __construct(
+ $bitsPerCharacter, $chars = NULL, $rightPadFinalBits = FALSE,
+ $padFinalGroup = FALSE, $padCharacter = '=')
+ {
+ // Ensure validity of $chars
+ if (!is_string($chars) || ($charLength = strlen($chars)) < 2) {
+ $chars =
+ '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ-,';
+ $charLength = 64;
+ }
+
+ // Ensure validity of $bitsPerCharacter
+ if ($bitsPerCharacter < 1) {
+ // $bitsPerCharacter must be at least 1
+ $bitsPerCharacter = 1;
+ $radix = 2;
+
+ } elseif ($charLength < 1 << $bitsPerCharacter) {
+ // Character length of $chars is too small for $bitsPerCharacter
+ // Set $bitsPerCharacter to greatest acceptable value
+ $bitsPerCharacter = 1;
+ $radix = 2;
+
+ while ($charLength >= ($radix <<= 1) && $bitsPerCharacter < 8) {
+ $bitsPerCharacter++;
+ }
+
+ $radix >>= 1;
+
+ } elseif ($bitsPerCharacter > 8) {
+ // $bitsPerCharacter must not be greater than 8
+ $bitsPerCharacter = 8;
+ $radix = 256;
+
+ } else {
+ $radix = 1 << $bitsPerCharacter;
+ }
+
+ $this->_chars = $chars;
+ $this->_bitsPerCharacter = $bitsPerCharacter;
+ $this->_radix = $radix;
+ $this->_rightPadFinalBits = $rightPadFinalBits;
+ $this->_padFinalGroup = $padFinalGroup;
+ $this->_padCharacter = $padCharacter[0];
+ }
+
+ /**
+ * Encode a string
+ *
+ * @param string $rawString Binary data to encode
+ * @return string
+ */
+ public function encode($rawString)
+ {
+ // Unpack string into an array of bytes
+ $bytes = unpack('C*', $rawString);
+ $byteCount = count($bytes);
+
+ $encodedString = '';
+ $byte = array_shift($bytes);
+ $bitsRead = 0;
+
+ $chars = $this->_chars;
+ $bitsPerCharacter = $this->_bitsPerCharacter;
+ $rightPadFinalBits = $this->_rightPadFinalBits;
+ $padFinalGroup = $this->_padFinalGroup;
+ $padCharacter = $this->_padCharacter;
+
+ // Generate encoded output;
+ // each loop produces one encoded character
+ for ($c = 0; $c < $byteCount * 8 / $bitsPerCharacter; $c++) {
+
+ // Get the bits needed for this encoded character
+ if ($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 * 8 / $bitsPerCharacter
+ - ceil((strlen($rawString) % $bytesPerGroup)
+ * 8 / $bitsPerCharacter);
+ $encodedString .= str_repeat($padCharacter[0], $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 $caseSensitive
+ * @param boolean $strict Returns NULL if $encodedString contains
+ * an undecodable character
+ * @return string|NULL
+ */
+ public function decode($encodedString, $caseSensitive = TRUE,
+ $strict = FALSE)
+ {
+ if (!$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 = $this->_padCharacter;
+
+ // Get index of encoded characters
+ if ($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
+ while ($encodedString[$lastNotatedIndex] == $padCharacter[0]) {
+ $encodedString = substr($encodedString, 0, $lastNotatedIndex);
+ $lastNotatedIndex--;
+ }
+
+ $rawString = '';
+ $byte = 0;
+ $bitsWritten = 0;
+
+ // Convert each encoded character to a series of unencoded bits
+ for ($c = 0; $c <= $lastNotatedIndex; $c++) {
+
+ if (!isset($charmap[$encodedString[$c]]) && !$caseSensitive) {
+ // Encoded character was not found; try other case
+ if (isset($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;
+ }
+}