<?php

/**

 * SimplePie

 *

 * A PHP-Based RSS and Atom Feed Framework.

 * Takes the hard work out of managing a complete RSS/Atom solution.

 *

 * Copyright (c) 2004-2022, Ryan Parman, Sam Sneddon, Ryan McCue, and contributors

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without modification, are

 * permitted provided that the following conditions are met:

 *

 * 	* Redistributions of source code must retain the above copyright notice, this list of

 * 	  conditions and the following disclaimer.

 *

 * 	* Redistributions in binary form must reproduce the above copyright notice, this list

 * 	  of conditions and the following disclaimer in the documentation and/or other materials

 * 	  provided with the distribution.

 *

 * 	* Neither the name of the SimplePie Team nor the names of its contributors may be used

 * 	  to endorse or promote products derived from this software without specific prior

 * 	  written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS

 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY

 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS

 * AND CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR

 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR

 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR

 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE

 * POSSIBILITY OF SUCH DAMAGE.

 *

 * @package SimplePie

 * @copyright 2004-2016 Ryan Parman, Sam Sneddon, Ryan McCue

 * @author Ryan Parman

 * @author Sam Sneddon

 * @author Ryan McCue

 * @link http://simplepie.org/ SimplePie

 * @license http://www.opensource.org/licenses/bsd-license.php BSD License

 */

namespace SimplePie\XML\Declaration;

/**

 * Parses the XML Declaration

 *

 * @package SimplePie

 * @subpackage Parsing

 */

class Parser

{

    /**

     * XML Version

     *

     * @access public

     * @var string

     */

    public $version = '1.0';

    /**

     * Encoding

     *

     * @access public

     * @var string

     */

    public $encoding = 'UTF-8';

    /**

     * Standalone

     *

     * @access public

     * @var bool

     */

    public $standalone = false;

    private const STATE_BEFORE_VERSION_NAME = 'before_version_name';

    private const STATE_VERSION_NAME = 'version_name';

    private const STATE_VERSION_EQUALS = 'version_equals';

    private const STATE_VERSION_VALUE = 'version_value';

    private const STATE_ENCODING_NAME = 'encoding_name';

    private const STATE_EMIT = 'emit';

    private const STATE_ENCODING_EQUALS = 'encoding_equals';

    private const STATE_STANDALONE_NAME = 'standalone_name';

    private const STATE_ENCODING_VALUE = 'encoding_value';

    private const STATE_STANDALONE_EQUALS = 'standalone_equals';

    private const STATE_STANDALONE_VALUE = 'standalone_value';

    private const STATE_ERROR = false;

    /**

     * Current state of the state machine

     *

     * @access private

     * @var self::STATE_*

     */

    public $state = self::STATE_BEFORE_VERSION_NAME;

    /**

     * Input data

     *

     * @access private

     * @var string

     */

    public $data = '';

    /**

     * Input data length (to avoid calling strlen() everytime this is needed)

     *

     * @access private

     * @var int

     */

    public $data_length = 0;

    /**

     * Current position of the pointer

     *

     * @var int

     * @access private

     */

    public $position = 0;

    /**

     * Create an instance of the class with the input data

     *

     * @access public

     * @param string $data Input data

     */

    public function __construct($data)

    {

        $this->data = $data;

        $this->data_length = strlen($this->data);

    }

    /**

     * Parse the input data

     *

     * @access public

     * @return bool true on success, false on failure

     */

    public function parse()

    {

        while ($this->state && $this->state !== self::STATE_EMIT && $this->has_data()) {

            $state = $this->state;

            $this->$state();

        }

        $this->data = '';

        if ($this->state === self::STATE_EMIT) {

            return true;

        }

        $this->version = '';

        $this->encoding = '';

        $this->standalone = '';

        return false;

    }

    /**

     * Check whether there is data beyond the pointer

     *

     * @access private

     * @return bool true if there is further data, false if not

     */

    public function has_data()

    {

        return (bool) ($this->position < $this->data_length);

    }

    /**

     * Advance past any whitespace

     *

     * @return int Number of whitespace characters passed

     */

    public function skip_whitespace()

    {

        $whitespace = strspn($this->data, "\x09\x0A\x0D\x20", $this->position);

        $this->position += $whitespace;

        return $whitespace;

    }

    /**

     * Read value

     */

    public function get_value()

    {

        $quote = substr($this->data, $this->position, 1);

        if ($quote === '"' || $quote === "'") {

            $this->position++;

            $len = strcspn($this->data, $quote, $this->position);

            if ($this->has_data()) {

                $value = substr($this->data, $this->position, $len);

                $this->position += $len + 1;

                return $value;

            }

        }

        return false;

    }

    public function before_version_name()

    {

        if ($this->skip_whitespace()) {

            $this->state = self::STATE_VERSION_NAME;

        } else {

            $this->state = self::STATE_ERROR;

        }

    }

    public function version_name()

    {

        if (substr($this->data, $this->position, 7) === 'version') {

            $this->position += 7;

            $this->skip_whitespace();

            $this->state = self::STATE_VERSION_EQUALS;

        } else {

            $this->state = self::STATE_ERROR;

        }

    }

    public function version_equals()

    {

        if (substr($this->data, $this->position, 1) === '=') {

            $this->position++;

            $this->skip_whitespace();

            $this->state = self::STATE_VERSION_VALUE;

        } else {

            $this->state = self::STATE_ERROR;

        }

    }

    public function version_value()

    {

        if ($this->version = $this->get_value()) {

            $this->skip_whitespace();

            if ($this->has_data()) {

                $this->state = self::STATE_ENCODING_NAME;

            } else {

                $this->state = self::STATE_EMIT;

            }

        } else {

            $this->state = self::STATE_ERROR;

        }

    }

    public function encoding_name()

    {

        if (substr($this->data, $this->position, 8) === 'encoding') {

            $this->position += 8;

            $this->skip_whitespace();

            $this->state = self::STATE_ENCODING_EQUALS;

        } else {

            $this->state = self::STATE_STANDALONE_NAME;

        }

    }

    public function encoding_equals()

    {

        if (substr($this->data, $this->position, 1) === '=') {

            $this->position++;

            $this->skip_whitespace();

            $this->state = self::STATE_ENCODING_VALUE;

        } else {

            $this->state = self::STATE_ERROR;

        }

    }

    public function encoding_value()

    {

        if ($this->encoding = $this->get_value()) {

            $this->skip_whitespace();

            if ($this->has_data()) {

                $this->state = self::STATE_STANDALONE_NAME;

            } else {

                $this->state = self::STATE_EMIT;

            }

        } else {

            $this->state = self::STATE_ERROR;

        }

    }

    public function standalone_name()

    {

        if (substr($this->data, $this->position, 10) === 'standalone') {

            $this->position += 10;

            $this->skip_whitespace();

            $this->state = self::STATE_STANDALONE_EQUALS;

        } else {

            $this->state = self::STATE_ERROR;

        }

    }

    public function standalone_equals()

    {

        if (substr($this->data, $this->position, 1) === '=') {

            $this->position++;

            $this->skip_whitespace();

            $this->state = self::STATE_STANDALONE_VALUE;

        } else {

            $this->state = self::STATE_ERROR;

        }

    }

    public function standalone_value()

    {

        if ($standalone = $this->get_value()) {

            switch ($standalone) {

                case 'yes':

                    $this->standalone = true;

                    break;

                case 'no':

                    $this->standalone = false;

                    break;

                default:

                    $this->state = self::STATE_ERROR;

                    return;

            }

            $this->skip_whitespace();

            if ($this->has_data()) {

                $this->state = self::STATE_ERROR;

            } else {

                $this->state = self::STATE_EMIT;

            }

        } else {

            $this->state = self::STATE_ERROR;

        }

    }

}

class_alias('SimplePie\XML\Declaration\Parser', 'SimplePie_XML_Declaration_Parser');