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<?php

/**

 * CodeIgniter

 *

 * An open source application development framework for PHP

 *

 * This content is released under the MIT License (MIT)

 *

 * Copyright (c) 2014 - 2016, British Columbia Institute of Technology

 *

 * Permission is hereby granted, free of charge, to any person obtaining a copy

 * of this software and associated documentation files (the "Software"), to deal

 * in the Software without restriction, including without limitation the rights

 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

 * copies of the Software, and to permit persons to whom the Software is

 * furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice shall be included in

 * all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

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

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN

 * THE SOFTWARE.

 *

 * @package	CodeIgniter

 * @author	EllisLab Dev Team

 * @copyright	Copyright (c) 2008 - 2014, EllisLab, Inc. (https://ellislab.com/)

 * @copyright	Copyright (c) 2014 - 2016, British Columbia Institute of Technology (http://bcit.ca/)

 * @license	http://opensource.org/licenses/MIT	MIT License

 * @link	https://codeigniter.com

 * @since	Version 1.0.0

 * @filesource

 */

defined('BASEPATH') OR exit('No direct script access allowed');

/**

 * CodeIgniter CAPTCHA Helper

 *

 * @package		CodeIgniter

 * @subpackage	Helpers

 * @category	Helpers

 * @author		EllisLab Dev Team

 * @link		https://codeigniter.com/user_guide/helpers/captcha_helper.html

 */

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

if ( ! function_exists('create_captcha'))

{

	/**

	 * Create CAPTCHA

	 *

	 * @param	array	$data		data for the CAPTCHA

	 * @param	string	$img_path	path to create the image in

	 * @param	string	$img_url	URL to the CAPTCHA image folder

	 * @param	string	$font_path	server path to font

	 * @return	string

	 */

	function create_captcha($data = '', $img_path = '', $img_url = '', $font_path = '')

	{

		$defaults = array(

			'word'		=> '',

			'img_path'	=> '',

			'img_url'	=> '',

			'img_width'	=> '150',

			'img_height'	=> '30',

			'font_path'	=> '',

			'expiration'	=> 7200,

			'word_length'	=> 8,

			'font_size'	=> 16,

			'img_id'	=> '',

			'pool'		=> '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ',

			'colors'	=> array(

				'background'	=> array(255,255,255),

				'border'	=> array(153,102,102),

				'text'		=> array(204,153,153),

				'grid'		=> array(255,182,182)

			)

		);

		foreach ($defaults as $key => $val)

		{

			if ( ! is_array($data) && empty($$key))

			{

				$$key = $val;

			}

			else

			{

				$$key = isset($data[$key]) ? $data[$key] : $val;

			}

		}

		if ($img_path === '' OR $img_url === ''

			OR ! is_dir($img_path) OR ! is_really_writable($img_path)

			OR ! extension_loaded('gd'))

		{

			return FALSE;

		}

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

		// Remove old images

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

		$now = microtime(TRUE);

		$current_dir = @opendir($img_path);

		while ($filename = @readdir($current_dir))

		{

			if (substr($filename, -4) === '.jpg' && (str_replace('.jpg', '', $filename) + $expiration) < $now)

			{

				@unlink($img_path.$filename);

			}

		}

		@closedir($current_dir);

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

		// Do we have a "word" yet?

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

		if (empty($word))

		{

			$word = '';

			$pool_length = strlen($pool);

			$rand_max = $pool_length - 1;

			// PHP7 or a suitable polyfill

			if (function_exists('random_int'))

			{

				try

				{

					for ($i = 0; $i < $word_length; $i++)

					{

						$word .= $pool[random_int(0, $rand_max)];

					}

				}

				catch (Exception $e)

				{

					// This means fallback to the next possible

					// alternative to random_int()

					$word = '';

				}

			}

		}

		if (empty($word))

		{

			// Nobody will have a larger character pool than

			// 256 characters, but let's handle it just in case ...

			//

			// No, I do not care that the fallback to mt_rand() can

			// handle it; if you trigger this, you're very obviously

			// trying to break it. -- Narf

			if ($pool_length > 256)

			{

				return FALSE;

			}

			// We'll try using the operating system's PRNG first,

			// which we can access through CI_Security::get_random_bytes()

			$security = get_instance()->security;

			// To avoid numerous get_random_bytes() calls, we'll

			// just try fetching as much bytes as we need at once.

			if (($bytes = $security->get_random_bytes($pool_length)) !== FALSE)

			{

				$byte_index = $word_index = 0;

				while ($word_index < $word_length)

				{

					// Do we have more random data to use?

					// It could be exhausted by previous iterations

					// ignoring bytes higher than $rand_max.

					if ($byte_index === $pool_length)

					{

						// No failures should be possible if the

						// first get_random_bytes() call didn't

						// return FALSE, but still ...

						for ($i = 0; $i < 5; $i++)

						{

							if (($bytes = $security->get_random_bytes($pool_length)) === FALSE)

							{

								continue;

							}

							$byte_index = 0;

							break;

						}

						if ($bytes === FALSE)

						{

							// Sadly, this means fallback to mt_rand()

							$word = '';

							break;

						}

					}

					list(, $rand_index) = unpack('C', $bytes[$byte_index++]);

					if ($rand_index > $rand_max)

					{

						continue;

					}

					$word .= $pool[$rand_index];

					$word_index++;

				}

			}

		}

		if (empty($word))

		{

			for ($i = 0; $i < $word_length; $i++)

			{

				$word .= $pool[mt_rand(0, $rand_max)];

			}

		}

		elseif ( ! is_string($word))

		{

			$word = (string) $word;

		}

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

		// Determine angle and position

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

		$length	= strlen($word);

		$angle	= ($length >= 6) ? mt_rand(-($length-6), ($length-6)) : 0;

		$x_axis	= mt_rand(6, (360/$length)-16);

		$y_axis = ($angle >= 0) ? mt_rand($img_height, $img_width) : mt_rand(6, $img_height);

		// Create image

		// PHP.net recommends imagecreatetruecolor(), but it isn't always available

		$im = function_exists('imagecreatetruecolor')

			? imagecreatetruecolor($img_width, $img_height)

			: imagecreate($img_width, $img_height);

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

		//  Assign colors

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

		is_array($colors) OR $colors = $defaults['colors'];

		foreach (array_keys($defaults['colors']) as $key)

		{

			// Check for a possible missing value

			is_array($colors[$key]) OR $colors[$key] = $defaults['colors'][$key];

			$colors[$key] = imagecolorallocate($im, $colors[$key][0], $colors[$key][1], $colors[$key][2]);

		}

		// Create the rectangle

		ImageFilledRectangle($im, 0, 0, $img_width, $img_height, $colors['background']);

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

		//  Create the spiral pattern

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

		$theta		= 1;

		$thetac		= 7;

		$radius		= 16;

		$circles	= 20;

		$points		= 32;

		for ($i = 0, $cp = ($circles * $points) - 1; $i < $cp; $i++)

		{

			$theta += $thetac;

			$rad = $radius * ($i / $points);

			$x = ($rad * cos($theta)) + $x_axis;

			$y = ($rad * sin($theta)) + $y_axis;

			$theta += $thetac;

			$rad1 = $radius * (($i + 1) / $points);

			$x1 = ($rad1 * cos($theta)) + $x_axis;

			$y1 = ($rad1 * sin($theta)) + $y_axis;

			imageline($im, $x, $y, $x1, $y1, $colors['grid']);

			$theta -= $thetac;

		}

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

		//  Write the text

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

		$use_font = ($font_path !== '' && file_exists($font_path) && function_exists('imagettftext'));

		if ($use_font === FALSE)

		{

			($font_size > 5) && $font_size = 5;

			$x = mt_rand(0, $img_width / ($length / 3));

			$y = 0;

		}

		else

		{

			($font_size > 30) && $font_size = 30;

			$x = mt_rand(0, $img_width / ($length / 1.5));

			$y = $font_size + 2;

		}

		for ($i = 0; $i < $length; $i++)

		{

			if ($use_font === FALSE)

			{

				$y = mt_rand(0 , $img_height / 2);

				imagestring($im, $font_size, $x, $y, $word[$i], $colors['text']);

				$x += ($font_size * 2);

			}

			else

			{

				$y = mt_rand($img_height / 2, $img_height - 3);

				imagettftext($im, $font_size, $angle, $x, $y, $colors['text'], $font_path, $word[$i]);

				$x += $font_size;

			}

		}

		// Create the border

		imagerectangle($im, 0, 0, $img_width - 1, $img_height - 1, $colors['border']);

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

		//  Generate the image

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

		$img_url = rtrim($img_url, '/').'/';

		if (function_exists('imagejpeg'))

		{

			$img_filename = $now.'.jpg';

			imagejpeg($im, $img_path.$img_filename);

		}

		elseif (function_exists('imagepng'))

		{

			$img_filename = $now.'.png';

			imagepng($im, $img_path.$img_filename);

		}

		else

		{

			return FALSE;

		}

		$img = '<img '.($img_id === '' ? '' : 'id="'.$img_id.'"').' src="'.$img_url.$img_filename.'" style="width: '.$img_width.'; height: '.$img_height .'; border: 0;" alt=" " />';

		ImageDestroy($im);

		return array('word' => $word, 'time' => $now, 'image' => $img, 'filename' => $img_filename);

	}

}