Proyectos de Subversion Moodle

<?php

namespace lbuchs\WebAuthn\Binary;

use lbuchs\WebAuthn\WebAuthnException;

/**

 * Modified version of https://github.com/madwizard-thomas/webauthn-server/blob/master/src/Format/ByteBuffer.php

 * Copyright © 2018 Thomas Bleeker - MIT licensed

 * Modified by Lukas Buchs

 * Thanks Thomas for your work!

 */

class ByteBuffer implements \JsonSerializable, \Serializable {

    /**

     * @var bool

     */

    public static $useBase64UrlEncoding = false;

    /**

     * @var string

     */

    private $_data;

    /**

     * @var int

     */

    private $_length;

    public function __construct($binaryData) {

        $this->_data = (string)$binaryData;

        $this->_length = \strlen($binaryData);

    }

    // -----------------------

    // PUBLIC STATIC

    // -----------------------

    /**

     * create a ByteBuffer from a base64 url encoded string

     * @param string $base64url

     * @return ByteBuffer

     */

    public static function fromBase64Url($base64url): ByteBuffer {

        $bin = self::_base64url_decode($base64url);

        if ($bin === false) {

            throw new WebAuthnException('ByteBuffer: Invalid base64 url string', WebAuthnException::BYTEBUFFER);

        }

        return new ByteBuffer($bin);

    }

    /**

     * create a ByteBuffer from a base64 url encoded string

     * @param string $hex

     * @return ByteBuffer

     */

    public static function fromHex($hex): ByteBuffer {

        $bin = \hex2bin($hex);

        if ($bin === false) {

            throw new WebAuthnException('ByteBuffer: Invalid hex string', WebAuthnException::BYTEBUFFER);

        }

        return new ByteBuffer($bin);

    }

    /**

     * create a random ByteBuffer

     * @param string $length

     * @return ByteBuffer

     */

    public static function randomBuffer($length): ByteBuffer {

        if (\function_exists('random_bytes')) { // >PHP 7.0

            return new ByteBuffer(\random_bytes($length));

        } else if (\function_exists('openssl_random_pseudo_bytes')) {

            return new ByteBuffer(\openssl_random_pseudo_bytes($length));

        } else {

            throw new WebAuthnException('ByteBuffer: cannot generate random bytes', WebAuthnException::BYTEBUFFER);

        }

    }

    // -----------------------

    // PUBLIC

    // -----------------------

    public function getBytes($offset, $length): string {

        if ($offset < 0 || $length < 0 || ($offset + $length > $this->_length)) {

            throw new WebAuthnException('ByteBuffer: Invalid offset or length', WebAuthnException::BYTEBUFFER);

        }

        return \substr($this->_data, $offset, $length);

    }

    public function getByteVal($offset): int {

        if ($offset < 0 || $offset >= $this->_length) {

            throw new WebAuthnException('ByteBuffer: Invalid offset', WebAuthnException::BYTEBUFFER);

        }

        return \ord(\substr($this->_data, $offset, 1));

    }

    public function getJson($jsonFlags=0) {

        $data = \json_decode($this->getBinaryString(), null, 512, $jsonFlags);

        if (\json_last_error() !== JSON_ERROR_NONE) {

            throw new WebAuthnException(\json_last_error_msg(), WebAuthnException::BYTEBUFFER);

        }

        return $data;

    }

    public function getLength(): int {

        return $this->_length;

    }

    public function getUint16Val($offset) {

        if ($offset < 0 || ($offset + 2) > $this->_length) {

            throw new WebAuthnException('ByteBuffer: Invalid offset', WebAuthnException::BYTEBUFFER);

        }

        return unpack('n', $this->_data, $offset)[1];

    }

    public function getUint32Val($offset) {

        if ($offset < 0 || ($offset + 4) > $this->_length) {

            throw new WebAuthnException('ByteBuffer: Invalid offset', WebAuthnException::BYTEBUFFER);

        }

        $val = unpack('N', $this->_data, $offset)[1];

        // Signed integer overflow causes signed negative numbers

        if ($val < 0) {

            throw new WebAuthnException('ByteBuffer: Value out of integer range.', WebAuthnException::BYTEBUFFER);

        }

        return $val;

    }

    public function getUint64Val($offset) {

        if (PHP_INT_SIZE < 8) {

            throw new WebAuthnException('ByteBuffer: 64-bit values not supported by this system', WebAuthnException::BYTEBUFFER);

        }

        if ($offset < 0 || ($offset + 8) > $this->_length) {

            throw new WebAuthnException('ByteBuffer: Invalid offset', WebAuthnException::BYTEBUFFER);

        }

        $val = unpack('J', $this->_data, $offset)[1];

        // Signed integer overflow causes signed negative numbers

        if ($val < 0) {

            throw new WebAuthnException('ByteBuffer: Value out of integer range.', WebAuthnException::BYTEBUFFER);

        }

        return $val;

    }

    public function getHalfFloatVal($offset) {

        //FROM spec pseudo decode_half(unsigned char *halfp)

        $half = $this->getUint16Val($offset);

        $exp = ($half >> 10) & 0x1f;

        $mant = $half & 0x3ff;

        if ($exp === 0) {

            $val = $mant * (2 ** -24);

        } elseif ($exp !== 31) {

            $val = ($mant + 1024) * (2 ** ($exp - 25));

        } else {

            $val = ($mant === 0) ? INF : NAN;

        }

        return ($half & 0x8000) ? -$val : $val;

    }

    public function getFloatVal($offset) {

        if ($offset < 0 || ($offset + 4) > $this->_length) {

            throw new WebAuthnException('ByteBuffer: Invalid offset', WebAuthnException::BYTEBUFFER);

        }

        return unpack('G', $this->_data, $offset)[1];

    }

    public function getDoubleVal($offset) {

        if ($offset < 0 || ($offset + 8) > $this->_length) {

            throw new WebAuthnException('ByteBuffer: Invalid offset', WebAuthnException::BYTEBUFFER);

        }

        return unpack('E', $this->_data, $offset)[1];

    }

    /**

     * @return string

     */

    public function getBinaryString(): string {

        return $this->_data;

    }

    /**

     * @param string|ByteBuffer $buffer

     * @return bool

     */

    public function equals($buffer): bool {

        if (is_object($buffer) && $buffer instanceof ByteBuffer) {

            return $buffer->getBinaryString() === $this->getBinaryString();

        } else if (is_string($buffer)) {

            return $buffer === $this->getBinaryString();

        }

        return false;

    }

    /**

     * @return string

     */

    public function getHex(): string {

        return \bin2hex($this->_data);

    }

    /**

     * @return bool

     */

    public function isEmpty(): bool {

        return $this->_length === 0;

    }

    /**

     * jsonSerialize interface

     * return binary data in RFC 1342-Like serialized string

     * @return string

     */

    public function jsonSerialize(): string {

        if (ByteBuffer::$useBase64UrlEncoding) {

            return self::_base64url_encode($this->_data);

        } else {

            return '=?BINARY?B?' . \base64_encode($this->_data) . '?=';

        }

    }

    /**

     * Serializable-Interface

     * @return string

     */

    public function serialize(): string {

        return \serialize($this->_data);

    }

    /**

     * Serializable-Interface

     * @param string $serialized

     */

    public function unserialize($serialized) {

        $this->_data = \unserialize($serialized);

        $this->_length = \strlen($this->_data);

    }

    /**

     * (PHP 8 deprecates Serializable-Interface)

     * @return array

     */

    public function __serialize(): array {

        return [

            'data' => \serialize($this->_data)

        ];

    }

    /**

     * object to string

     * @return string

     */

    public function __toString(): string {

        return $this->getHex();

    }

    /**

     * (PHP 8 deprecates Serializable-Interface)

     * @param array $data

     * @return void

     */

    public function __unserialize($data) {

        if ($data && isset($data['data'])) {

            $this->_data = \unserialize($data['data']);

            $this->_length = \strlen($this->_data);

        }

    }

    // -----------------------

    // PROTECTED STATIC

    // -----------------------

    /**

     * base64 url decoding

     * @param string $data

     * @return string

     */

    protected static function _base64url_decode($data): string {

        return \base64_decode(\strtr($data, '-_', '+/') . \str_repeat('=', 3 - (3 + \strlen($data)) % 4));

    }

    /**

     * base64 url encoding

     * @param string $data

     * @return string

     */

    protected static function _base64url_encode($data): string {

        return \rtrim(\strtr(\base64_encode($data), '+/', '-_'), '=');

    }

}