/system/helpers/captcha_helper.php

<?php  if ( ! defined('BASEPATH')) exit('No direct script access allowed');
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP 5.1.6 or newer
 *
 * @package		CodeIgniter
 * @author		EllisLab Dev Team
 * @copyright		Copyright (c) 2008 - 2014, EllisLab, Inc.
 * @copyright		Copyright (c) 2014 - 2015, British Columbia Institute of Technology (http://bcit.ca/)
 * @license		http://codeigniter.com/user_guide/license.html
 * @link		http://codeigniter.com
 * @since		Version 1.0
 * @filesource
 */

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

/**
 * CodeIgniter CAPTCHA Helper
 *
 * @package		CodeIgniter
 * @subpackage	Helpers
 * @category	Helpers
 * @author		EllisLab Dev Team
 * @link		http://codeigniter.com/user_guide/helpers/xml_helper.html
 */

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

/**
 * Create CAPTCHA
 *
 * @access	public
 * @param	array	array of data for the CAPTCHA
 * @param	string	path to create the image in
 * @param	string	URL to the CAPTCHA image folder
 * @param	string	server path to font
 * @return	string
 */
if ( ! function_exists('create_captcha'))
{
	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);

		foreach ($defaults as $key => $val)
		{
			if ( ! is_array($data))
			{
				if ( ! isset($$key) OR $$key == '')
				{
					$$key = $val;
				}
			}
			else
			{
				$$key = ( ! isset($data[$key])) ? $val : $data[$key];
			}
		}

		if ($img_path == '' OR $img_url == '')
		{
			return FALSE;
		}

		if ( ! @is_dir($img_path))
		{
			return FALSE;
		}

		if ( ! is_writable($img_path))
		{
			return FALSE;
		}

		if ( ! extension_loaded('gd'))
		{
			return FALSE;
		}

		// -----------------------------------
		// Remove old images
		// -----------------------------------

		list($usec, $sec) = explode(" ", microtime());
		$now = ((float)$usec + (float)$sec);

		$current_dir = @opendir($img_path);

		while ($filename = @readdir($current_dir))
		{
			if ($filename != "." and $filename != ".." and $filename != "index.html")
			{
				$name = str_replace(".jpg", "", $filename);

				if (($name + $expiration) < $now)
				{
					@unlink($img_path.$filename);
				}
			}
		}

		@closedir($current_dir);

		// -----------------------------------
		// Do we have a "word" yet?
		// -----------------------------------

		// -----------------------------------
		// Do we have a "word" yet?
		// -----------------------------------

		if (empty($word))
		{
			$word = '';
			$pool = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
			$pool_length = strlen($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($word))
		{
			// To avoid numerous get_random_bytes() calls, we'll
			// just try fetching as much bytes as we need at once.
			if (($bytes = _ci_captcha_get_random_bytes($pool_length)) !== FALSE)
			{
				$byte_index = $word_index = 0;
				while ($word_index < $word_length)
				{
					if (($rand_index = unpack('C', $bytes[$byte_index++])) > $rand_max)
					{
						// Was this the last byte we have?
						// If so, try to fetch more.
						if ($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 = _ci_captcha_get_random_bytes($pool_length)) === FALSE)
								{
									continue;
								}

								$byte_index = 0;
								break;
							}

							if ($bytes === FALSE)
							{
								// Sadly, this means fallback to mt_rand()
								$word = '';
								break;
							}
						}

						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) ? rand(-($length-6), ($length-6)) : 0;
		$x_axis	= rand(6, (360/$length)-16);
		$y_axis = ($angle >= 0 ) ? rand($img_height, $img_width) : rand(6, $img_height);

		// -----------------------------------
		// Create image
		// -----------------------------------

		// PHP.net recommends imagecreatetruecolor(), but it isn't always available
		if (function_exists('imagecreatetruecolor'))
		{
			$im = imagecreatetruecolor($img_width, $img_height);
		}
		else
		{
			$im = imagecreate($img_width, $img_height);
		}

		// -----------------------------------
		//  Assign colors
		// -----------------------------------

		$bg_color		= imagecolorallocate ($im, 255, 255, 255);
		$border_color	= imagecolorallocate ($im, 153, 102, 102);
		$text_color		= imagecolorallocate ($im, 204, 153, 153);
		$grid_color		= imagecolorallocate($im, 255, 182, 182);
		$shadow_color	= imagecolorallocate($im, 255, 240, 240);

		// -----------------------------------
		//  Create the rectangle
		// -----------------------------------

		ImageFilledRectangle($im, 0, 0, $img_width, $img_height, $bg_color);

		// -----------------------------------
		//  Create the spiral pattern
		// -----------------------------------

		$theta		= 1;
		$thetac		= 7;
		$radius		= 16;
		$circles	= 20;
		$points		= 32;

		for ($i = 0; $i < ($circles * $points) - 1; $i++)
		{
			$theta = $theta + $thetac;
			$rad = $radius * ($i / $points );
			$x = ($rad * cos($theta)) + $x_axis;
			$y = ($rad * sin($theta)) + $y_axis;
			$theta = $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, $grid_color);
			$theta = $theta - $thetac;
		}

		// -----------------------------------
		//  Write the text
		// -----------------------------------

		$use_font = ($font_path != '' AND file_exists($font_path) AND function_exists('imagettftext')) ? TRUE : FALSE;

		if ($use_font == FALSE)
		{
			$font_size = 5;
			$x = rand(0, $img_width/($length/3));
			$y = 0;
		}
		else
		{
			$font_size	= 16;
			$x = rand(0, $img_width/($length/1.5));
			$y = $font_size+2;
		}

		for ($i = 0; $i < strlen($word); $i++)
		{
			if ($use_font == FALSE)
			{
				$y = rand(0 , $img_height/2);
				imagestring($im, $font_size, $x, $y, substr($word, $i, 1), $text_color);
				$x += ($font_size*2);
			}
			else
			{
				$y = rand($img_height/2, $img_height-3);
				imagettftext($im, $font_size, $angle, $x, $y, $text_color, $font_path, substr($word, $i, 1));
				$x += $font_size;
			}
		}


		// -----------------------------------
		//  Create the border
		// -----------------------------------

		imagerectangle($im, 0, 0, $img_width-1, $img_height-1, $border_color);

		// -----------------------------------
		//  Generate the image
		// -----------------------------------

		$img_name = $now.'.jpg';

		ImageJPEG($im, $img_path.$img_name);

		$img = "<img src=\"$img_url$img_name\" width=\"$img_width\" height=\"$img_height\" style=\"border:0;\" alt=\" \" />";

		ImageDestroy($im);

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

	function _ci_captcha_get_random_bytes($length)
	{
		if (defined('MCRYPT_DEV_URANDOM'))
		{
			return mcrypt_create_iv($length, MCRYPT_DEV_URANDOM);
		}
		elseif (function_exists('openssl_random_pseudo_bytes'))
		{
			return openssl_random_pseudo_bytes($length);
		}

		return FALSE;
	}
}

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

/* End of file captcha_helper.php */
/* Location: ./system/heleprs/captcha_helper.php */