<?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\HTTP;

/**

 * HTTP Response Parser

 *

 * @package SimplePie

 * @subpackage HTTP

 */

class Parser

{

    /**

     * HTTP Version

     *

     * @var float

     */

    public $http_version = 0.0;

    /**

     * Status code

     *

     * @var int

     */

    public $status_code = 0;

    /**

     * Reason phrase

     *

     * @var string

     */

    public $reason = '';

    /**

     * Key/value pairs of the headers

     *

     * @var array

     */

    public $headers = [];

    /**

     * Body of the response

     *

     * @var string

     */

    public $body = '';

    private const STATE_HTTP_VERSION = 'http_version';

    private const STATE_STATUS = 'status';

    private const STATE_REASON = 'reason';

    private const STATE_NEW_LINE = 'new_line';

    private const STATE_BODY = 'body';

    private const STATE_NAME = 'name';

    private const STATE_VALUE = 'value';

    private const STATE_VALUE_CHAR = 'value_char';

    private const STATE_QUOTE = 'quote';

    private const STATE_QUOTE_ESCAPED = 'quote_escaped';

    private const STATE_QUOTE_CHAR = 'quote_char';

    private const STATE_CHUNKED = 'chunked';

    private const STATE_EMIT = 'emit';

    private const STATE_ERROR = false;

    /**

     * Current state of the state machine

     *

     * @var self::STATE_*

     */

    protected $state = self::STATE_HTTP_VERSION;

    /**

     * Input data

     *

     * @var string

     */

    protected $data = '';

    /**

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

     *

     * @var int

     */

    protected $data_length = 0;

    /**

     * Current position of the pointer

     *

     * @var int

     */

    protected $position = 0;

    /**

     * Name of the hedaer currently being parsed

     *

     * @var string

     */

    protected $name = '';

    /**

     * Value of the hedaer currently being parsed

     *

     * @var string

     */

    protected $value = '';

    /**

     * Create an instance of the class with the input data

     *

     * @param string $data Input data

     */

    public function __construct($data)

    {

        $this->data = $data;

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

    }

    /**

     * Parse the input data

     *

     * @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 || $this->state === self::STATE_BODY) {

            return true;

        }

        $this->http_version = '';

        $this->status_code = 0;

        $this->reason = '';

        $this->headers = [];

        $this->body = '';

        return false;

    }

    /**

     * Check whether there is data beyond the pointer

     *

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

     */

    protected function has_data()

    {

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

    }

    /**

     * See if the next character is LWS

     *

     * @return bool true if the next character is LWS, false if not

     */

    protected function is_linear_whitespace()

    {

        return (bool) ($this->data[$this->position] === "\x09"

            || $this->data[$this->position] === "\x20"

            || ($this->data[$this->position] === "\x0A"

                && isset($this->data[$this->position + 1])

                && ($this->data[$this->position + 1] === "\x09" || $this->data[$this->position + 1] === "\x20")));

    }

    /**

     * Parse the HTTP version

     */

    protected function http_version()

    {

        if (strpos($this->data, "\x0A") !== false && strtoupper(substr($this->data, 0, 5)) === 'HTTP/') {

            $len = strspn($this->data, '0123456789.', 5);

            $this->http_version = substr($this->data, 5, $len);

            $this->position += 5 + $len;

            if (substr_count($this->http_version, '.') <= 1) {

                $this->http_version = (float) $this->http_version;

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

                $this->state = self::STATE_STATUS;

            } else {

                $this->state = self::STATE_ERROR;

            }

        } else {

            $this->state = self::STATE_ERROR;

        }

    }

    /**

     * Parse the status code

     */

    protected function status()

    {

        if ($len = strspn($this->data, '0123456789', $this->position)) {

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

            $this->position += $len;

            $this->state = self::STATE_REASON;

        } else {

            $this->state = self::STATE_ERROR;

        }

    }

    /**

     * Parse the reason phrase

     */

    protected function reason()

    {

        $len = strcspn($this->data, "\x0A", $this->position);

        $this->reason = trim(substr($this->data, $this->position, $len), "\x09\x0D\x20");

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

        $this->state = self::STATE_NEW_LINE;

    }

    /**

     * Deal with a new line, shifting data around as needed

     */

    protected function new_line()

    {

        $this->value = trim($this->value, "\x0D\x20");

        if ($this->name !== '' && $this->value !== '') {

            $this->name = strtolower($this->name);

            // We should only use the last Content-Type header. c.f. issue #1

            if (isset($this->headers[$this->name]) && $this->name !== 'content-type') {

                $this->headers[$this->name] .= ', ' . $this->value;

            } else {

                $this->headers[$this->name] = $this->value;

            }

        }

        $this->name = '';

        $this->value = '';

        if (substr($this->data[$this->position], 0, 2) === "\x0D\x0A") {

            $this->position += 2;

            $this->state = self::STATE_BODY;

        } elseif ($this->data[$this->position] === "\x0A") {

            $this->position++;

            $this->state = self::STATE_BODY;

        } else {

            $this->state = self::STATE_NAME;

        }

    }

    /**

     * Parse a header name

     */

    protected function name()

    {

        $len = strcspn($this->data, "\x0A:", $this->position);

        if (isset($this->data[$this->position + $len])) {

            if ($this->data[$this->position + $len] === "\x0A") {

                $this->position += $len;

                $this->state = self::STATE_NEW_LINE;

            } else {

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

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

                $this->state = self::STATE_VALUE;

            }

        } else {

            $this->state = self::STATE_ERROR;

        }

    }

    /**

     * Parse LWS, replacing consecutive LWS characters with a single space

     */

    protected function linear_whitespace()

    {

        do {

            if (substr($this->data, $this->position, 2) === "\x0D\x0A") {

                $this->position += 2;

            } elseif ($this->data[$this->position] === "\x0A") {

                $this->position++;

            }

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

        } while ($this->has_data() && $this->is_linear_whitespace());

        $this->value .= "\x20";

    }

    /**

     * See what state to move to while within non-quoted header values

     */

    protected function value()

    {

        if ($this->is_linear_whitespace()) {

            $this->linear_whitespace();

        } else {

            switch ($this->data[$this->position]) {

                case '"':

                    // Workaround for ETags: we have to include the quotes as

                    // part of the tag.

                    if (strtolower($this->name) === 'etag') {

                        $this->value .= '"';

                        $this->position++;

                        $this->state = self::STATE_VALUE_CHAR;

                        break;

                    }

                    $this->position++;

                    $this->state = self::STATE_QUOTE;

                    break;

                case "\x0A":

                    $this->position++;

                    $this->state = self::STATE_NEW_LINE;

                    break;

                default:

                    $this->state = self::STATE_VALUE_CHAR;

                    break;

            }

        }

    }

    /**

     * Parse a header value while outside quotes

     */

    protected function value_char()

    {

        $len = strcspn($this->data, "\x09\x20\x0A\"", $this->position);

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

        $this->position += $len;

        $this->state = self::STATE_VALUE;

    }

    /**

     * See what state to move to while within quoted header values

     */

    protected function quote()

    {

        if ($this->is_linear_whitespace()) {

            $this->linear_whitespace();

        } else {

            switch ($this->data[$this->position]) {

                case '"':

                    $this->position++;

                    $this->state = self::STATE_VALUE;

                    break;

                case "\x0A":

                    $this->position++;

                    $this->state = self::STATE_NEW_LINE;

                    break;

                case '\\':

                    $this->position++;

                    $this->state = self::STATE_QUOTE_ESCAPED;

                    break;

                default:

                    $this->state = self::STATE_QUOTE_CHAR;

                    break;

            }

        }

    }

    /**

     * Parse a header value while within quotes

     */

    protected function quote_char()

    {

        $len = strcspn($this->data, "\x09\x20\x0A\"\\", $this->position);

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

        $this->position += $len;

        $this->state = self::STATE_VALUE;

    }

    /**

     * Parse an escaped character within quotes

     */

    protected function quote_escaped()

    {

        $this->value .= $this->data[$this->position];

        $this->position++;

        $this->state = self::STATE_QUOTE;

    }