<?php

// error_reporting(E_ALL); ini_set('display_errors', 1); // uncomment this line for debugging

/**
 * Project:     Securimage: A PHP class for creating and managing form CAPTCHA images<br />
 * File:        securimage.php<br />
 *
 * Copyright (c) 2013, Drew Phillips
 * 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.
 *
 * 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 HOLDER OR 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.
 *
 * Any modifications to the library should be indicated clearly in the source code
 * to inform users that the changes are not a part of the original software.<br /><br />
 *
 * If you found this script useful, please take a quick moment to rate it.<br />
 * http://www.hotscripts.com/rate/49400.html  Thanks.
 *
 * @link http://www.phpcaptcha.org Securimage PHP CAPTCHA
 * @link http://www.phpcaptcha.org/latest.zip Download Latest Version
 * @link http://www.phpcaptcha.org/Securimage_Docs/ Online Documentation
 * @copyright 2013 Drew Phillips
 * @author Drew Phillips <drew@drew-phillips.com>
 * @version 3.5 (April 2013)
 * @package Securimage
 *
 */

/**
ChangeLog

3.5
- Release new version
- MB string support for charlist
- Modify audio file path to use language directories
- Changed default captcha appearance

3.2RC4
- Add MySQL, PostgreSQL, and SQLite3 support for database storage
- Deprecate "use_sqlite_db" option and remove SQLite2/sqlite_* functions
- Add new captcha type that displays 2 dictionary words on one image
- Update examples

3.2RC3
- Fix canSendHeaders() check which was breaking if a PHP startup error was issued

3.2RC2
- Add error handler (https://github.com/dapphp/securimage/issues/15)
- Fix flash examples to use the correct value name for audio parameter

3.2RC1
- New audio captcha code.  Faster, fully dynamic audio, full WAV support
(Paul Voegler, Drew Phillips) <http://voegler.eu/pub/audio>
- New Flash audio streaming button.  User defined image and size supported
- Additional options for customizing captcha (noise_level, send_headers,
no_exit, no_session, display_value
- Add captcha ID support.  Uses sqlite and unique captcha IDs to track captchas,
no session used
- Add static methods for creating and validating captcha by ID
- Automatic clearing of old codes from SQLite database

3.0.3Beta
- Add improved mixing function to WavFile class (Paul Voegler)
- Improve performance and security of captcha audio (Paul Voegler, Drew Phillips)
- Add option to use random file as background noise in captcha audio
- Add new securimage options for audio files

3.0.2Beta
- Fix issue with session variables when upgrading from 2.0 - 3.0
- Improve audio captcha, switch to use WavFile class, make mathematical captcha audio work

3.0.1
- Bugfix: removed use of deprecated variable in addSignature method that would cause errors with display_errors on

3.0
- Rewrite class using PHP5 OOP
- Remove support for GD fonts, require FreeType
- Remove support for multi-color codes
- Add option to make codes case-sensitive
- Add namespaces to support multiple captchas on a single page or page specific captchas
- Add option to show simple math problems instead of codes
- Remove support for mp3 files due to vulnerability in decoding mp3 audio files
- Create new flash file to stream wav files instead of mp3
- Changed to BSD license

2.0.2
- Fix pathing to make integration into libraries easier (Nathan Phillip Brink ohnobinki@ohnopublishing.net)

2.0.1
- Add support for browsers with cookies disabled (requires php5, sqlite) maps users to md5 hashed ip addresses and md5 hashed codes for security
- Add fallback to gd fonts if ttf support is not enabled or font file not found (Mike Challis http://www.642weather.com/weather/scripts.php)
- Check for previous definition of image type constants (Mike Challis)
- Fix mime type settings for audio output
- Fixed color allocation issues with multiple colors and background images, consolidate allocation to one function
- Ability to let codes expire after a given length of time
- Allow HTML color codes to be passed to Securimage_Color (suggested by Mike Challis)

2.0.0
- Add mathematical distortion to characters (using code from HKCaptcha)
- Improved session support
- Added Securimage_Color class for easier color definitions
- Add distortion to audio output to prevent binary comparison attack (proposed by Sven "SavageTiger" Hagemann [insecurity.nl])
- Flash button to stream mp3 audio (Douglas Walsh www.douglaswalsh.net)
- Audio output is mp3 format by default
- Change font to AlteHaasGrotesk by yann le coroller
- Some code cleanup

1.0.4 (unreleased)
- Ability to output audible codes in mp3 format to stream from flash

1.0.3.1
- Error reading from wordlist in some cases caused words to be cut off 1 letter short

1.0.3
- Removed shadow_text from code which could cause an undefined property error due to removal from previous version

1.0.2
- Audible CAPTCHA Code wav files
- Create codes from a word list instead of random strings

1.0
- Added the ability to use a selected character set, rather than a-z0-9 only.
- Added the multi-color text option to use different colors for each letter.
- Switched to automatic session handling instead of using files for code storage
- Added GD Font support if ttf support is not available.  Can use internal GD fonts or load new ones.
- Added the ability to set line thickness
- Added option for drawing arced lines over letters
- Added ability to choose image type for output

 */


/**
 * Securimage CAPTCHA Class.
 *
 * @version    3.5
 * @package    Securimage
 * @subpackage classes
 * @author     Drew Phillips <drew@drew-phillips.com>
 *
 */
class Securimage
{
	// All of the public variables below are securimage options
	// They can be passed as an array to the Securimage constructor, set below,
	// or set from securimage_show.php and securimage_play.php

	/**
	 * Renders captcha as a JPEG image
	 * @var int
	 */
	const SI_IMAGE_JPEG = 1;
	/**
	 * Renders captcha as a PNG image (default)
	 * @var int
	 */
	const SI_IMAGE_PNG = 2;
	/**
	 * Renders captcha as a GIF image
	 * @var int
	 */
	const SI_IMAGE_GIF = 3;

	/**
	 * Create a normal alphanumeric captcha
	 * @var int
	 */
	const SI_CAPTCHA_STRING = 0;
	/**
	 * Create a captcha consisting of a simple math problem
	 * @var int
	 */
	const SI_CAPTCHA_MATHEMATIC = 1;
	/**
	 * Create a word based captcha using 2 words
	 * @var int
	 */
	const SI_CAPTCHA_WORDS = 2;

	/**
	 * MySQL option identifier for database storage option
	 *
	 * @var string
	 */
	const SI_DRIVER_MYSQL = 'mysql';

	/**
	 * PostgreSQL option identifier for database storage option
	 *
	 * @var string
	 */
	const SI_DRIVER_PGSQL = 'pgsql';

	/**
	 * SQLite option identifier for database storage option
	 *
	 * @var string
	 */
	const SI_DRIVER_SQLITE3 = 'sqlite';

	/*%*********************************************************************%*/
	// Properties

	/**
	 * The width of the captcha image
	 * @var int
	 */
	public $image_width = 215;
	/**
	 * The height of the captcha image
	 * @var int
	 */
	public $image_height = 80;
	/**
	 * The type of the image, default = png
	 * @var int
	 */
	public $image_type = self::SI_IMAGE_PNG;

	/**
	 * The background color of the captcha
	 * @var Securimage_Color
	 */
	public $image_bg_color = '#ffffff';
	/**
	 * The color of the captcha text
	 * @var Securimage_Color
	 */
	public $text_color = '#707070';
	/**
	 * The color of the lines over the captcha
	 * @var Securimage_Color
	 */
	public $line_color = '#707070';
	/**
	 * The color of the noise that is drawn
	 * @var Securimage_Color
	 */
	public $noise_color = '#707070';

	/**
	 * How transparent to make the text 0 = completely opaque, 100 = invisible
	 * @var int
	 */
	public $text_transparency_percentage = 20;
	/**
	 * Whether or not to draw the text transparently, true = use transparency, false = no transparency
	 * @var bool
	 */
	public $use_transparent_text = true;

	/**
	 * The length of the captcha code
	 * @var int
	 */
	public $code_length = 6;
	/**
	 * Whether the captcha should be case sensitive (not recommended, use only for maximum protection)
	 * @var bool
	 */
	public $case_sensitive = false;
	/**
	 * The character set to use for generating the captcha code
	 * @var string
	 */
	public $charset = 'ABCDEFGHKLMNPRSTUVWYZabcdefghklmnprstuvwyz23456789';
	/**
	 * How long in seconds a captcha remains valid, after this time it will not be accepted
	 * @var unknown_type
	 */
	public $expiry_time = 900;

	/**
	 * The session name securimage should use, only set this if your application uses a custom session name
	 * It is recommended to set this value below so it is used by all securimage scripts
	 * @var string
	 */
	public $session_name = null;

	/**
	 * true to use the wordlist file, false to generate random captcha codes
	 * @var bool
	 */
	public $use_wordlist = false;

	/**
	 * The level of distortion, 0.75 = normal, 1.0 = very high distortion
	 * @var double
	 */
	public $perturbation = 0.85;
	/**
	 * How many lines to draw over the captcha code to increase security
	 * @var int
	 */
	public $num_lines = 5;
	/**
	 * The level of noise (random dots) to place on the image, 0-10
	 * @var int
	 */
	public $noise_level = 2;

	/**
	 * The signature text to draw on the bottom corner of the image
	 * @var string
	 */
	public $image_signature = '';
	/**
	 * The color of the signature text
	 * @var Securimage_Color
	 */
	public $signature_color = '#707070';
	/**
	 * The path to the ttf font file to use for the signature text, defaults to $ttf_file (AHGBold.ttf)
	 * @var string
	 */
	public $signature_font;

	/**
	 * DO NOT USE!!!
	 * Use an SQLite database to store data (for users that do not support cookies)
	 * @var bool
	 * @see Securimage::$use_sqlite_db
	 * @deprecated 3.2RC4
	 */
	public $use_sqlite_db = false;

	/**
	 * Use a database backend for code storage.
	 * Provides a fallback to users with cookies disabled.
	 * Required when using captcha IDs.
	 *
	 * @see Securimage::$database_driver
	 * @var bool
	 */
	public $use_database = false;

	/**
	 * Database driver to use for database support.
	 * Allowable values: 'mysql', 'pgsql', 'sqlite'.
	 * Default: sqlite
	 *
	 * @var string
	 */
	public $database_driver = self::SI_DRIVER_SQLITE3;

	/**
	 * Database host to connect to when using mysql or postgres
	 * On Linux use "localhost" for Unix domain socket, otherwise uses TCP/IP
	 * Does not apply to SQLite
	 *
	 * @var string
	 */
	public $database_host = 'localhost';

	/**
	 * Database username for connection (mysql, postgres only)
	 * Default is an empty string
	 *
	 * @var string
	 */
	public $database_user = '';

	/**
	 * Database password for connection (mysql, postgres only)
	 * Default is empty string
	 *
	 * @var string
	 */
	public $database_pass = '';

	/**
	 * Name of the database to select (mysql, postgres only)
	 *
	 * @see Securimage::$database_file for SQLite
	 * @var string
	 */
	public $database_name = '';

	/**
	 * Database table where captcha codes are stored
	 * Note: Securimage will attempt to create this table for you if it does
	 * not exist.  If the table cannot be created, an E_USER_WARNING is emitted.
	 *
	 * @var string
	 */
	public $database_table = 'captcha_codes';

	/**
	 * Fully qualified path to the database file when using SQLite3.
	 * This value is only used when $database_driver == sqlite3 and does
	 * not apply when no database is used, or when using MySQL or PostgreSQL.
	 *
	 * @var string
	 */
	public $database_file;

	/**
	 * The type of captcha to create, either alphanumeric, or a math problem<br />
	 * Securimage::SI_CAPTCHA_STRING or Securimage::SI_CAPTCHA_MATHEMATIC
	 * @var int
	 */
	public $captcha_type = self::SI_CAPTCHA_STRING; // or self::SI_CAPTCHA_MATHEMATIC;

	/**
	 * The captcha namespace, use this if you have multiple forms on a single page, blank if you do not use multiple forms on one page
	 * @var string
	 * <code>
	 * <?php
	 * // in securimage_show.php (create one show script for each form)
	 * $img->namespace = 'contact_form';
	 *
	 * // in form validator
	 * $img->namespace = 'contact_form';
	 * if ($img->check($code) == true) {
	 *     echo "Valid!";
	 *  }
	 * </code>
	 */
	public $namespace;

	/**
	 * The font file to use to draw the captcha code, leave blank for default font AHGBold.ttf
	 * @var string
	 */
	public $ttf_file;
	/**
	 * The path to the wordlist file to use, leave blank for default words/words.txt
	 * @var string
	 */
	public $wordlist_file;
	/**
	 * The directory to scan for background images, if set a random background will be chosen from this folder
	 * @var string
	 */
	public $background_directory;
	/**
	 * The path to the SQLite database file to use, if $use_sqlite_database = true, should be chmod 666
	 * @deprecated 3.2RC4
	 * @var string
	 */
	public $sqlite_database;
	/**
	 * The path to the securimage audio directory, can be set in securimage_play.php
	 * @var string
	 * <code>
	 * $img->audio_path = '/home/yoursite/public_html/securimage/audio/en/';
	 * </code>
	 */
	public $audio_path;
	/**
	 * The path to the directory containing audio files that will be selected
	 * randomly and mixed with the captcha audio.
	 *
	 * @var string
	 */
	public $audio_noise_path;
	/**
	 * Whether or not to mix background noise files into captcha audio (true = mix, false = no)
	 * Mixing random background audio with noise can help improve security of audio captcha.
	 * Default: securimage/audio/noise
	 *
	 * @since 3.0.3
	 * @see Securimage::$audio_noise_path
	 * @var bool
	 */
	public $audio_use_noise;
	/**
	 * The method and threshold (or gain factor) used to normalize the mixing with background noise.
	 * See http://www.voegler.eu/pub/audio/ for more information.
	 *
	 * Valid: <ul>
	 *     <li> >= 1 - Normalize by multiplying by the threshold (boost - positive gain). <br />
	 *            A value of 1 in effect means no normalization (and results in clipping). </li>
	 *     <li> <= -1 - Normalize by dividing by the the absolute value of threshold (attenuate - negative gain). <br />
	 *            A factor of 2 (-2) is about 6dB reduction in volume.</li>
	 *     <li> [0, 1) - (open inverval - not including 1) - The threshold
	 *            above which amplitudes are comressed logarithmically. <br />
	 *            e.g. 0.6 to leave amplitudes up to 60% "as is" and compress above. </li>
	 *     <li> (-1, 0) - (open inverval - not including -1 and 0) - The threshold
	 *            above which amplitudes are comressed linearly. <br />
	 *            e.g. -0.6 to leave amplitudes up to 60% "as is" and compress above. </li></ul>
	 *
	 * Default: 0.6
	 *
	 * @since 3.0.4
	 * @var float
	 */
	public $audio_mix_normalization = 0.6;
	/**
	 * Whether or not to degrade audio by introducing random noise (improves security of audio captcha)
	 * Default: true
	 *
	 * @since 3.0.3
	 * @var bool
	 */
	public $degrade_audio;
	/**
	 * Minimum delay to insert between captcha audio letters in milliseconds
	 *
	 * @since 3.0.3
	 * @var float
	 */
	public $audio_gap_min = 0;
	/**
	 * Maximum delay to insert between captcha audio letters in milliseconds
	 *
	 * @since 3.0.3
	 * @var float
	 */
	public $audio_gap_max = 600;

	/**
	 * Captcha ID if using static captcha
	 * @var string Unique captcha id
	 */
	protected static $_captchaId = null;

	protected $im;
	protected $tmpimg;
	protected $bgimg;
	protected $iscale = 5;

	public $securimage_path = null;

	/**
	 * The captcha challenge value (either the case-sensitive/insensitive word captcha, or the solution to the math captcha)
	 *
	 * @var string Captcha challenge value
	 */
	protected $code;

	/**
	 * The display value of the captcha to draw on the image (the word captcha, or the math equation to present to the user)
	 *
	 * @var string Captcha display value to draw on the image
	 */
	protected $code_display;

	/**
	 * A value that can be passed to the constructor that can be used to generate a captcha image with a given value
	 * This value does not get stored in the session or database and is only used when calling Securimage::show().
	 * If a display_value was passed to the constructor and the captcha image is generated, the display_value will be used
	 * as the string to draw on the captcha image.  Used only if captcha codes are generated and managed by a 3rd party app/library
	 *
	 * @var string Captcha code value to display on the image
	 */
	public $display_value;

	/**
	 * Captcha code supplied by user [set from Securimage::check()]
	 *
	 * @var string
	 */
	protected $captcha_code;

	/**
	 * Flag that can be specified telling securimage not to call exit after generating a captcha image or audio file
	 *
	 * @var bool If true, script will not terminate; if false script will terminate (default)
	 */
	protected $no_exit;

	/**
	 * Flag indicating whether or not a PHP session should be started and used
	 *
	 * @var bool If true, no session will be started; if false, session will be started and used to store data (default)
	 */
	protected $no_session;

	/**
	 * Flag indicating whether or not HTTP headers will be sent when outputting captcha image/audio
	 *
	 * @var bool If true (default) headers will be sent, if false, no headers are sent
	 */
	protected $send_headers;

	/**
	 * PDO connection when a database is used
	 *
	 * @var resource
	 */
	protected $pdo_conn;

	// gd color resources that are allocated for drawing the image
	protected $gdbgcolor;
	protected $gdtextcolor;
	protected $gdlinecolor;
	protected $gdsignaturecolor;

	/**
	 * Create a new securimage object, pass options to set in the constructor.<br />
	 * This can be used to display a captcha, play an audible captcha, or validate an entry
	 * @param array $options
	 * <code>
	 * $options = array(
	 *     'text_color' => new Securimage_Color('#013020'),
	 *     'code_length' => 5,
	 *     'num_lines' => 5,
	 *     'noise_level' => 3,
	 *     'font_file' => Securimage::getPath() . '/custom.ttf'
	 * );
	 *
	 * $img = new Securimage($options);
	 * </code>
	 */
	public function __construct($options = array())
	{
		$this->securimage_path = dirname(__FILE__);

		if (is_array($options) && sizeof($options) > 0)
		{
			foreach ($options as $prop => $val)
			{
				if ($prop == 'captchaId')
				{
					Securimage::$_captchaId = $val;
					$this->use_database = true;
				}
				else if ($prop == 'use_sqlite_db')
				{
					trigger_error("The use_sqlite_db option is deprecated, use 'use_database' instead", E_USER_NOTICE);
				}
				else
				{
					$this->$prop = $val;
				}
			}
		}

		$this->image_bg_color = $this->initColor($this->image_bg_color, '#ffffff');
		$this->text_color = $this->initColor($this->text_color, '#616161');
		$this->line_color = $this->initColor($this->line_color, '#616161');
		$this->noise_color = $this->initColor($this->noise_color, '#616161');
		$this->signature_color = $this->initColor($this->signature_color, '#616161');

		if (is_null($this->ttf_file))
		{
			$this->ttf_file = $this->securimage_path . '/AHGBold.ttf';
		}

		$this->signature_font = $this->ttf_file;

		if (is_null($this->wordlist_file))
		{
			$this->wordlist_file = $this->securimage_path . '/words/words.txt';
		}

		if (is_null($this->database_file))
		{
			$this->database_file = $this->securimage_path . '/database/securimage.sq3';
		}

		if (is_null($this->audio_path))
		{
			$this->audio_path = $this->securimage_path . '/audio/en/';
		}

		if (is_null($this->audio_noise_path))
		{
			$this->audio_noise_path = $this->securimage_path . '/audio/noise/';
		}

		if (is_null($this->audio_use_noise))
		{
			$this->audio_use_noise = true;
		}

		if (is_null($this->degrade_audio))
		{
			$this->degrade_audio = true;
		}

		if (is_null($this->code_length) || (int) $this->code_length < 1)
		{
			$this->code_length = 6;
		}

		if (is_null($this->perturbation) || !is_numeric($this->perturbation))
		{
			$this->perturbation = 0.75;
		}

		if (is_null($this->namespace) || !is_string($this->namespace))
		{
			$this->namespace = 'default';
		}

		if (is_null($this->no_exit))
		{
			$this->no_exit = false;
		}

		if (is_null($this->no_session))
		{
			$this->no_session = false;
		}

		if (is_null($this->send_headers))
		{
			$this->send_headers = false;
		}

		if ($this->no_session != true)
		{
			// Initialize session or attach to existing
			if (session_id() == '')
			{ // no session has been started yet, which is needed for validation
				if (!is_null($this->session_name) && trim($this->session_name) != '')
				{
					session_name(trim($this->session_name)); // set session name if provided
				}
				session_start();
			}
		}
	}

	/**
	 * Return the absolute path to the Securimage directory
	 * @return string The path to the securimage base directory
	 */
	public static function getPath()
	{
		return dirname(__FILE__);
	}

	/**
	 * Generate a new captcha ID or retrieve the current ID
	 *
	 * @param $new bool If true, generates a new challenge and returns and ID
	 * @param $options array Additional options to be passed to Securimage.
	 * Must include database options if not set directly in securimage.php
	 *
	 * @return null|string Returns null if no captcha id set and new was false, or string captcha ID
	 */
	public static function getCaptchaId($new = true, array $options = array())
	{
		if (is_null($new) || (bool) $new == true)
		{
			$id = sha1(uniqid($_SERVER['REMOTE_ADDR'], true));
			$opts = array('no_session' => true, 'use_database' => true);
			if (sizeof($options) > 0)
				$opts = array_merge($options, $opts);
			$si = new self($opts);
			Securimage::$_captchaId = $id;
			$si->createCode();

			return $id;
		}
		else
		{
			return Securimage::$_captchaId;
		}
	}

	/**
	 * Validate a captcha code input against a captcha ID
	 *
	 * @param string $id       The captcha ID to check
	 * @param string $value    The captcha value supplied by the user
	 * @param array  $options  Array of options to construct Securimage with.
	 * Options must include database options if they are not set in securimage.php
	 *
	 * @see Securimage::$database_driver
	 * @return bool true if the code was valid for the given captcha ID, false if not or if database failed to open
	 */
	public static function checkByCaptchaId($id, $value, array $options = array())
	{
		$opts = array('captchaId' => $id, 'no_session' => true, 'use_database' => true);

		if (sizeof($options) > 0)
			$opts = array_merge($options, $opts);

		$si = new self($opts);

		if ($si->openDatabase())
		{
			$code = $si->getCodeFromDatabase();

			if (is_array($code))
			{
				$si->code = $code['code'];
				$si->code_display = $code['code_disp'];
			}

			if ($si->check($value))
			{
				$si->clearCodeFromDatabase();

				return true;
			}
			else
			{
				return false;
			}
		}
		else
		{
			return false;
		}
	}


	/**
	 * Used to serve a captcha image to the browser
	 * @param string $background_image The path to the background image to use
	 * <code>
	 * $img = new Securimage();
	 * $img->code_length = 6;
	 * $img->num_lines   = 5;
	 * $img->noise_level = 5;
	 *
	 * $img->show(); // sends the image to browser
	 * exit;
	 * </code>
	 */
	public function show($background_image = '')
	{
		set_error_handler(array(&$this, 'errorHandler'));

		if ($background_image != '' && is_readable($background_image))
		{
			$this->bgimg = $background_image;
		}

		$this->doImage();
	}

	/**
	 * Check a submitted code against the stored value
	 * @param string $code  The captcha code to check
	 * <code>
	 * $code = $_POST['code'];
	 * $img  = new Securimage();
	 * if ($img->check($code) == true) {
	 *     $captcha_valid = true;
	 * } else {
	 *     $captcha_valid = false;
	 * }
	 * </code>
	 */
	public function check($code)
	{
		$this->code_entered = $code;
		$this->validate();
		return $this->correct_code;
	}

	/**
	 * Output a wav file of the captcha code to the browser
	 *
	 * <code>
	 * $img = new Securimage();
	 * $img->outputAudioFile(); // outputs a wav file to the browser
	 * exit;
	 * </code>
	 */
	public function outputAudioFile()
	{
		set_error_handler(array(&$this, 'errorHandler'));

		require_once dirname(__FILE__) . '/WavFile.php';

		try
		{
			$audio = $this->getAudibleCode();
		}
		catch (Exception $ex)
		{
			if (($fp = @fopen(dirname(__FILE__) . '/si.error_log', 'a+')) !== false)
			{
				fwrite($fp, date('Y-m-d H:i:s') . ': Securimage audio error "' . $ex->getMessage() . '"' . "\n");
				fclose($fp);
			}

			$audio = $this->audioError();
		}

		if ($this->canSendHeaders() || $this->send_headers == false)
		{
			if ($this->send_headers)
			{
				$uniq = md5(uniqid(microtime()));
				header("Content-Disposition: attachment; filename=\"securimage_audio-{$uniq}.wav\"");
				header('Cache-Control: no-store, no-cache, must-revalidate');
				header('Expires: Sun, 1 Jan 2000 12:00:00 GMT');
				header('Last-Modified: ' . gmdate('D, d M Y H:i:s') . 'GMT');
				header('Content-type: audio/x-wav');

				if (extension_loaded('zlib'))
				{
					ini_set('zlib.output_compression', true); // compress output if supported by browser
				}
				else
				{
					header('Content-Length: ' . strlen($audio));
				}
			}

			echo $audio;
		}
		else
		{
			echo '<hr /><strong>' . 'Failed to generate audio file, content has already been ' . 'output.<br />This is most likely due to misconfiguration or ' . 'a PHP error was sent to the browser.</strong>';
		}

		restore_error_handler();

		if (!$this->no_exit)
			exit;
	}

	/**
	 * Return the code from the session or sqlite database if used.  If none exists yet, an empty string is returned
	 *
	 * @param $array bool   True to receive an array containing the code and properties
	 * @return array|string Array if $array = true, otherwise a string containing the code
	 */
	public function getCode($array = false, $returnExisting = false)
	{
		$code = '';
		$time = 0;
		$disp = 'error';

		if ($returnExisting && strlen($this->code) > 0)
		{
			if ($array)
			{
				return array('code' => $this->code, 'display' => $this->code_display, 'code_display' => $this->code_display, 'time' => 0);
			}
			else
			{
				return $this->code;
			}
		}

		if ($this->no_session != true)
		{
			if (isset($_SESSION['securimage_code_value'][$this->namespace]) && trim($_SESSION['securimage_code_value'][$this->namespace]) != '')
			{
				if ($this->isCodeExpired($_SESSION['securimage_code_ctime'][$this->namespace]) == false)
				{
					$code = $_SESSION['securimage_code_value'][$this->namespace];
					$time = $_SESSION['securimage_code_ctime'][$this->namespace];
					$disp = $_SESSION['securimage_code_disp'] [$this->namespace];
				}
			}
		}

		if (empty($code) && $this->use_database)
		{
			// no code in session - may mean user has cookies turned off
			$this->openDatabase();
			$code = $this->getCodeFromDatabase();
		}
		else
		{ /* no code stored in session or sqlite database, validation will fail */
		}

		if ($array == true)
		{
			return array('code' => $code, 'ctime' => $time, 'display' => $disp);
		}
		else
		{
			return $code;
		}
	}

	/**
	 * The main image drawing routing, responsible for constructing the entire image and serving it
	 */
	protected function doImage()
	{
		if (($this->use_transparent_text == true || $this->bgimg != '') && function_exists('imagecreatetruecolor'))
		{
			$imagecreate = 'imagecreatetruecolor';
		}
		else
		{
			$imagecreate = 'imagecreate';
		}

		$this->im = $imagecreate($this->image_width, $this->image_height);
		$this->tmpimg = $imagecreate($this->image_width * $this->iscale, $this->image_height * $this->iscale);

		$this->allocateColors();
		imagepalettecopy($this->tmpimg, $this->im);

		$this->setBackground();

		$code = '';

		if ($this->getCaptchaId(false) !== null)
		{
			// a captcha Id was supplied

			// check to see if a display_value for the captcha image was set
			if (is_string($this->display_value) && strlen($this->display_value) > 0)
			{
				$this->code_display = $this->display_value;
				$this->code = ($this->case_sensitive)?$this->display_value:strtolower($this->display_value);
				$code = $this->code;
			}
			else if ($this->openDatabase())
			{
				// no display_value, check the database for existing captchaId
				$code = $this->getCodeFromDatabase();

				// got back a result from the database with a valid code for captchaId
				if (is_array($code))
				{
					$this->code = $code['code'];
					$this->code_display = $code['code_disp'];
					$code = $code['code'];
				}
			}
		}

		if ($code == '')
		{
			// if the code was not set using display_value or was not found in
			// the database, create a new code
			$this->createCode();
		}

		if ($this->noise_level > 0)
		{
			$this->drawNoise();
		}

		$this->drawWord();

		if ($this->perturbation > 0 && is_readable($this->ttf_file))
		{
			$this->distortedCopy();
		}

		if ($this->num_lines > 0)
		{
			$this->drawLines();
		}

		if (trim($this->image_signature) != '')
		{
			$this->addSignature();
		}

		$this->output();
	}

	/**
	 * Allocate the colors to be used for the image
	 */
	protected function allocateColors()
	{
		// allocate bg color first for imagecreate
		$this->gdbgcolor = imagecolorallocate($this->im, $this->image_bg_color->r, $this->image_bg_color->g, $this->image_bg_color->b);

		$alpha = intval($this->text_transparency_percentage / 100 * 127);

		if ($this->use_transparent_text == true)
		{
			$this->gdtextcolor = imagecolorallocatealpha($this->im, $this->text_color->r, $this->text_color->g, $this->text_color->b, $alpha);
			$this->gdlinecolor = imagecolorallocatealpha($this->im, $this->line_color->r, $this->line_color->g, $this->line_color->b, $alpha);
			$this->gdnoisecolor = imagecolorallocatealpha($this->im, $this->noise_color->r, $this->noise_color->g, $this->noise_color->b, $alpha);
		}
		else
		{
			$this->gdtextcolor = imagecolorallocate($this->im, $this->text_color->r, $this->text_color->g, $this->text_color->b);
			$this->gdlinecolor = imagecolorallocate($this->im, $this->line_color->r, $this->line_color->g, $this->line_color->b);
			$this->gdnoisecolor = imagecolorallocate($this->im, $this->noise_color->r, $this->noise_color->g, $this->noise_color->b);
		}

		$this->gdsignaturecolor = imagecolorallocate($this->im, $this->signature_color->r, $this->signature_color->g, $this->signature_color->b);

	}

	/**
	 * The the background color, or background image to be used
	 */
	protected function setBackground()
	{
		// set background color of image by drawing a rectangle since imagecreatetruecolor doesn't set a bg color
		imagefilledrectangle($this->im, 0, 0, $this->image_width, $this->image_height, $this->gdbgcolor);
		imagefilledrectangle($this->tmpimg, 0, 0, $this->image_width * $this->iscale, $this->image_height * $this->iscale, $this->gdbgcolor);

		if ($this->bgimg == '')
		{
			if ($this->background_directory != null && is_dir($this->background_directory) && is_readable($this->background_directory))
			{
				$img = $this->getBackgroundFromDirectory();
				if ($img != false)
				{
					$this->bgimg = $img;
				}
			}
		}

		if ($this->bgimg == '')
		{
			return;
		}

		$dat = @getimagesize($this->bgimg);
		if ($dat == false)
		{
			return;
		}

		switch ($dat[2])
		{
			case 1:
				$newim = @imagecreatefromgif($this->bgimg);
				break;
			case 2:
				$newim = @imagecreatefromjpeg($this->bgimg);
				break;
			case 3:
				$newim = @imagecreatefrompng($this->bgimg);
				break;
			default:
				return;
		}

		if (!$newim)
			return;

		imagecopyresized($this->im, $newim, 0, 0, 0, 0, $this->image_width, $this->image_height, imagesx($newim), imagesy($newim));
	}

	/**
	 * Scan the directory for a background image to use
	 */
	protected function getBackgroundFromDirectory()
	{
		$images = array();

		if (($dh = opendir($this->background_directory)) !== false)
		{
			while (($file = readdir($dh)) !== false)
			{
				if (preg_match('/(jpg|gif|png)$/i', $file))
					$images[] = $file;
			}

			closedir($dh);

			if (sizeof($images) > 0)
			{
				return rtrim($this->background_directory, '/') . '/' . $images[mt_rand(0, sizeof($images) - 1)];
			}
		}

		return false;
	}

	/**
	 * Generates the code or math problem and saves the value to the session
	 */
	public function createCode()
	{
		$this->code = false;

		switch ($this->captcha_type)
		{
			case self::SI_CAPTCHA_MATHEMATIC:
			{
				do
				{
					$signs = array('+', '-', 'x');
					$left = mt_rand(1, 10);
					$right = mt_rand(1, 5);
					$sign = $signs[mt_rand(0, 2)];

					switch ($sign)
					{
						case 'x':
							$c = $left * $right;
							break;
						case '-':
							$c = $left - $right;
							break;
						default:
							$c = $left + $right;
							break;
					}
				} while ($c <= 0); // no negative #'s or 0

				$this->code = $c;
				$this->code_display = "$left $sign $right";
				break;
			}

			case self::SI_CAPTCHA_WORDS:
				$words = $this->readCodeFromFile(2);
				$this->code = implode(' ', $words);
				$this->code_display = $this->code;
				break;

			default:
				{
				if ($this->use_wordlist && is_readable($this->wordlist_file))
				{
					$this->code = $this->readCodeFromFile();
				}

				if ($this->code == false)
				{
					$this->code = $this->generateCode($this->code_length);
				}

				$this->code_display = $this->code;
				$this->code = ($this->case_sensitive)?$this->code:strtolower($this->code);
				} // default
		}

		$this->saveData();
	}

	/**
	 * Draws the captcha code on the image
	 */
	protected function drawWord()
	{
		$width2 = $this->image_width * $this->iscale;
		$height2 = $this->image_height * $this->iscale;

		if (!is_readable($this->ttf_file))
		{
			imagestring($this->im, 4, 10, ($this->image_height / 2) - 5, 'Failed to load TTF font file!', $this->gdtextcolor);
		}
		else
		{
			if ($this->perturbation > 0)
			{
				$font_size = $height2 * .4;
				$bb = imageftbbox($font_size, 0, $this->ttf_file, $this->code_display);
				$tx = $bb[4] - $bb[0];
				$ty = $bb[5] - $bb[1];
				$x = floor($width2 / 2 - $tx / 2 - $bb[0]);
				$y = round($height2 / 2 - $ty / 2 - $bb[1]);

				imagettftext($this->tmpimg, $font_size, 0, $x, $y, $this->gdtextcolor, $this->ttf_file, $this->code_display);
			}
			else
			{
				$font_size = $this->image_height * .4;
				$bb = imageftbbox($font_size, 0, $this->ttf_file, $this->code_display);
				$tx = $bb[4] - $bb[0];
				$ty = $bb[5] - $bb[1];
				$x = floor($this->image_width / 2 - $tx / 2 - $bb[0]);
				$y = round($this->image_height / 2 - $ty / 2 - $bb[1]);

				imagettftext($this->im, $font_size, 0, $x, $y, $this->gdtextcolor, $this->ttf_file, $this->code_display);
			}
		}

		// DEBUG
		//$this->im = $this->tmpimg;
		//$this->output();

	}

	/**
	 * Copies the captcha image to the final image with distortion applied
	 */
	protected function distortedCopy()
	{
		$numpoles = 3; // distortion factor
		// make array of poles AKA attractor points
		for ($i = 0; $i < $numpoles; ++$i)
		{
			$px[$i] = mt_rand($this->image_width * 0.2, $this->image_width * 0.8);
			$py[$i] = mt_rand($this->image_height * 0.2, $this->image_height * 0.8);
			$rad[$i] = mt_rand($this->image_height * 0.2, $this->image_height * 0.8);
			$tmp = ((-$this->frand()) * 0.15) - .15;
			$amp[$i] = $this->perturbation * $tmp;
		}

		$bgCol = imagecolorat($this->tmpimg, 0, 0);
		$width2 = $this->iscale * $this->image_width;
		$height2 = $this->iscale * $this->image_height;
		imagepalettecopy($this->im, $this->tmpimg); // copy palette to final image so text colors come across
		// loop over $img pixels, take pixels from $tmpimg with distortion field
		for ($ix = 0; $ix < $this->image_width; ++$ix)
		{
			for ($iy = 0; $iy < $this->image_height; ++$iy)
			{
				$x = $ix;
				$y = $iy;
				for ($i = 0; $i < $numpoles; ++$i)
				{
					$dx = $ix - $px[$i];
					$dy = $iy - $py[$i];
					if ($dx == 0 && $dy == 0)
					{
						continue;
					}
					$r = sqrt($dx * $dx + $dy * $dy);
					if ($r > $rad[$i])
					{
						continue;
					}
					$rscale = $amp[$i] * sin(3.14 * $r / $rad[$i]);
					$x += $dx * $rscale;
					$y += $dy * $rscale;
				}
				$c = $bgCol;
				$x *= $this->iscale;
				$y *= $this->iscale;
				if ($x >= 0 && $x < $width2 && $y >= 0 && $y < $height2)
				{
					$c = imagecolorat($this->tmpimg, $x, $y);
				}
				if ($c != $bgCol)
				{ // only copy pixels of letters to preserve any background image
					imagesetpixel($this->im, $ix, $iy, $c);
				}
			}
		}
	}

	/**
	 * Draws distorted lines on the image
	 */
	protected function drawLines()
	{
		for ($line = 0; $line < $this->num_lines; ++$line)
		{
			$x = $this->image_width * (1 + $line) / ($this->num_lines + 1);
			$x += (0.5 - $this->frand()) * $this->image_width / $this->num_lines;
			$y = mt_rand($this->image_height * 0.1, $this->image_height * 0.9);

			$theta = ($this->frand() - 0.5) * M_PI * 0.7;
			$w = $this->image_width;
			$len = mt_rand($w * 0.4, $w * 0.7);
			$lwid = mt_rand(0, 2);

			$k = $this->frand() * 0.6 + 0.2;
			$k = $k * $k * 0.5;
			$phi = $this->frand() * 6.28;
			$step = 0.5;
			$dx = $step * cos($theta);
			$dy = $step * sin($theta);
			$n = $len / $step;
			$amp = 1.5 * $this->frand() / ($k + 5.0 / $len);
			$x0 = $x - 0.5 * $len * cos($theta);
			$y0 = $y - 0.5 * $len * sin($theta);

			$ldx = round(-$dy * $lwid);
			$ldy = round($dx * $lwid);

			for ($i = 0; $i < $n; ++$i)
			{
				$x = $x0 + $i * $dx + $amp * $dy * sin($k * $i * $step + $phi);
				$y = $y0 + $i * $dy - $amp * $dx * sin($k * $i * $step + $phi);
				imagefilledrectangle($this->im, $x, $y, $x + $lwid, $y + $lwid, $this->gdlinecolor);
			}
		}
	}

	/**
	 * Draws random noise on the image
	 */
	protected function drawNoise()
	{
		if ($this->noise_level > 10)
		{
			$noise_level = 10;
		}
		else
		{
			$noise_level = $this->noise_level;
		}

		$t0 = microtime(true);

		$noise_level *= 125; // an arbitrary number that works well on a 1-10 scale

		$points = $this->image_width * $this->image_height * $this->iscale;
		$height = $this->image_height * $this->iscale;
		$width = $this->image_width * $this->iscale;
		for ($i = 0; $i < $noise_level; ++$i)
		{
			$x = mt_rand(10, $width);
			$y = mt_rand(10, $height);
			$size = mt_rand(7, 10);
			if ($x - $size <= 0 && $y - $size <= 0)
				continue; // dont cover 0,0 since it is used by imagedistortedcopy
			imagefilledarc($this->tmpimg, $x, $y, $size, $size, 0, 360, $this->gdnoisecolor, IMG_ARC_PIE);
		}

		$t1 = microtime(true);

		$t = $t1 - $t0;

		/*
		// DEBUG
		imagestring($this->tmpimg, 5, 25, 30, "$t", $this->gdnoisecolor);
		header('content-type: image/png');
		imagepng($this->tmpimg);
		exit;
		*/
	}

	/**
	 * Print signature text on image
	 */
	protected function addSignature()
	{
		$bbox = imagettfbbox(10, 0, $this->signature_font, $this->image_signature);
		$textlen = $bbox[2] - $bbox[0];
		$x = $this->image_width - $textlen - 5;
		$y = $this->image_height - 3;

		imagettftext($this->im, 10, 0, $x, $y, $this->gdsignaturecolor, $this->signature_font, $this->image_signature);
	}

	/**
	 * Sends the appropriate image and cache headers and outputs image to the browser
	 */
	protected function output()
	{
		if ($this->canSendHeaders() || $this->send_headers == false)
		{
			if ($this->send_headers)
			{
				// only send the content-type headers if no headers have been output
				// this will ease debugging on misconfigured servers where warnings
				// may have been output which break the image and prevent easily viewing
				// source to see the error.
				header("Expires: Mon, 26 Jul 1997 05:00:00 GMT");
				header("Last-Modified: " . gmdate("D, d M Y H:i:s") . "GMT");
				header("Cache-Control: no-store, no-cache, must-revalidate");
				header("Cache-Control: post-check=0, pre-check=0", false);
				header("Pragma: no-cache");
			}

			switch ($this->image_type)
			{
				case self::SI_IMAGE_JPEG:
					if ($this->send_headers)
						header("Content-Type: image/jpeg");
					imagejpeg($this->im, null, 90);
					break;
				case self::SI_IMAGE_GIF:
					if ($this->send_headers)
						header("Content-Type: image/gif");
					imagegif($this->im);
					break;
				default:
					if ($this->send_headers)
						header("Content-Type: image/png");
					imagepng($this->im);
					break;
			}
		}
		else
		{
			echo '<hr /><strong>' . 'Failed to generate captcha image, content has already been ' . 'output.<br />This is most likely due to misconfiguration or ' . 'a PHP error was sent to the browser.</strong>';
		}

		imagedestroy($this->im);
		restore_error_handler();

		//if (!$this->no_exit) exit;
	}

	/**
	 * Gets the code and returns the binary audio file for the stored captcha code
	 *
	 * @return The audio representation of the captcha in Wav format
	 */
	protected function getAudibleCode()
	{
		$letters = array();
		$code = $this->getCode(true, true);

		if ($code['code'] == '')
		{
			if (strlen($this->display_value) > 0)
			{
				$code = array('code' => $this->display_value, 'display' => $this->display_value);
			}
			else
			{
				$this->createCode();
				$code = $this->getCode(true);
			}
		}

		if (preg_match('/(\d+) (\+|-|x) (\d+)/i', $code['display'], $eq))
		{
			$math = true;

			$left = $eq[1];
			$sign = str_replace(array('+', '-', 'x'), array('plus', 'minus', 'times'), $eq[2]);
			$right = $eq[3];

			$letters = array($left, $sign, $right);
		}
		else
		{
			$math = false;

			$length = strlen($code['display']);

			for ($i = 0; $i < $length; ++$i)
			{
				$letter = $code['display']{$i};
				$letters[] = $letter;
			}
		}

		try
		{
			return $this->generateWAV($letters);
		}
		catch (Exception $ex)
		{
			throw $ex;
		}
	}

	/**
	 * Gets a captcha code from a wordlist
	 */
	protected function readCodeFromFile($numWords = 1)
	{
		$fp = fopen($this->wordlist_file, 'rb');
		if (!$fp)
			return false;

		$fsize = filesize($this->wordlist_file);
		if ($fsize < 128)
			return false; // too small of a list to be effective

		if ((int) $numWords < 1 || (int) $numWords > 5)
			$numWords = 1;

		$words = array();
		$i = 0;
		do
		{
			fseek($fp, mt_rand(0, $fsize - 64), SEEK_SET); // seek to a random position of file from 0 to filesize-64
			$data = fread($fp, 64); // read a chunk from our random position
			$data = preg_replace("/\r?\n/", "\n", $data);

			$start = @strpos($data, "\n", mt_rand(0, 56)) + 1; // random start position
			$end = @strpos($data, "\n", $start); // find end of word

			if ($start === false)
			{
				// picked start position at end of file
				continue;
			}
			else if ($end === false)
			{
				$end = strlen($data);
			}

			$word = strtolower(substr($data, $start, $end - $start)); // return a line of the file
			$words[] = $word;
		} while (++$i < $numWords);

		fclose($fp);

		if ($numWords < 2)
		{
			return $words[0];
		}
		else
		{
			return $words;
		}
	}

	/**
	 * Generates a random captcha code from the set character set
	 */
	protected function generateCode()
	{
		$code = '';

		if (function_exists('mb_strlen'))
		{
			for ($i = 1, $cslen = mb_strlen($this->charset); $i <= $this->code_length; ++$i)
			{
				$code .= mb_substr($this->charset, mt_rand(0, $cslen - 1), 1, 'UTF-8');
			}
		}
		else
		{
			for ($i = 1, $cslen = strlen($this->charset); $i <= $this->code_length; ++$i)
			{
				$code .= substr($this->charset, mt_rand(0, $cslen - 1), 1);
			}
		}

		return $code;
	}

	/**
	 * Checks the entered code against the value stored in the session or sqlite database, handles case sensitivity
	 * Also clears the stored codes if the code was entered correctly to prevent re-use
	 */
	protected function validate()
	{
		if (!is_string($this->code) || strlen($this->code) == 0)
		{
			$code = $this->getCode();
			// returns stored code, or an empty string if no stored code was found
			// checks the session and database if enabled
		}
		else
		{
			$code = $this->code;
		}

		if ($this->case_sensitive == false && preg_match('/[A-Z]/', $code))
		{
			// case sensitive was set from securimage_show.php but not in class
			// the code saved in the session has capitals so set case sensitive to true
			$this->case_sensitive = true;
		}

		$code_entered = trim((($this->case_sensitive)?$this->code_entered:strtolower($this->code_entered)));
		$this->correct_code = false;

		if ($code != '')
		{
			if (strpos($code, ' ') !== false)
			{
				// for multi word captchas, remove more than once space from input
				$code_entered = preg_replace('/\s+/', ' ', $code_entered);
				$code_entered = strtolower($code_entered);
			}

			if ($code == $code_entered)
			{
				$this->correct_code = true;
				if ($this->no_session != true)
				{
					$_SESSION['securimage_code_value'][$this->namespace] = '';
					$_SESSION['securimage_code_ctime'][$this->namespace] = '';
				}
				$this->clearCodeFromDatabase();
			}
		}
	}

	/**
	 * Save data to session namespace and database if used
	 */
	protected function saveData()
	{
		if ($this->no_session != true)
		{
			if (isset($_SESSION['securimage_code_value']) && is_scalar($_SESSION['securimage_code_value']))
			{
				// fix for migration from v2 - v3
				unset($_SESSION['securimage_code_value']);
				unset($_SESSION['securimage_code_ctime']);
			}

			$_SESSION['securimage_code_disp'] [$this->namespace] = $this->code_display;
			$_SESSION['securimage_code_value'][$this->namespace] = $this->code;
			$_SESSION['securimage_code_ctime'][$this->namespace] = time();
		}

		if ($this->use_database)
		{
			$this->saveCodeToDatabase();
		}
	}

	/**
	 * Saves the code to the sqlite database
	 */
	protected function saveCodeToDatabase()
	{
		$success = false;
		$this->openDatabase();

		if ($this->use_database && $this->pdo_conn)
		{
			$id = $this->getCaptchaId(false);
			$ip = $_SERVER['REMOTE_ADDR'];

			if (empty($id))
			{
				$id = $ip;
			}

			$time = time();
			$code = $this->code;
			$code_disp = $this->code_display;

			// This is somewhat expensive in PDO Sqlite3 (when there is something to delete)
			$this->clearCodeFromDatabase();

			$query = "INSERT INTO {$this->database_table} (" . "id, code, code_display, namespace, created) " . "VALUES(?, ?, ?, ?, ?)";

			$stmt = $this->pdo_conn->prepare($query);
			$success = $stmt->execute(array($id, $code, $code_disp, $this->namespace, $time));

			if (!$success)
			{
				$err = $stmt->errorInfo();
				trigger_error("Failed to insert code into database. {$err[1]}: {$err[2]}", E_USER_WARNING);
			}
		}

		return $success !== false;
	}

	/**
	 * Open sqlite database
	 */
	protected function openDatabase()
	{
		$this->pdo_conn = false;

		if ($this->use_database)
		{
			$pdo_extension = 'PDO_' . strtoupper($this->database_driver);

			if (!extension_loaded($pdo_extension))
			{
				trigger_error("Database support is turned on in Securimage, but the chosen extension $pdo_extension is not loaded in PHP.", E_USER_WARNING);
				return false;
			}
		}

		if ($this->database_driver == self::SI_DRIVER_SQLITE3)
		{
			if (!file_exists($this->database_file))
			{
				$fp = fopen($this->database_file, 'w+');
				if (!$fp)
				{
					$err = error_get_last();
					trigger_error("Securimage failed to create SQLite3 database file '{$this->database_file}'. Reason: {$err['message']}", E_USER_WARNING);
					return false;
				}
				fclose($fp);
				chmod($this->database_file, 0666);
			}
			else if (!is_writeable($this->database_file))
			{
				trigger_error("Securimage does not have read/write access to database file '{$this->database_file}. Make sure permissions are 0666 and writeable by user '" . get_current_user() . "'", E_USER_WARNING);
				return false;
			}
		}

		$dsn = $this->getDsn();

		try
		{
			$options = array();
			$this->pdo_conn = new PDO($dsn, $this->database_user, $this->database_pass, $options);
		}
		catch (PDOException $pdoex)
		{
			trigger_error("Database connection failed: " . $pdoex->getMessage(), E_USER_WARNING);
			return false;
		}

		try
		{
			if (!$this->checkTablesExist())
			{
				// create tables...
				$this->createDatabaseTables();
			}
		}
		catch (Exception $ex)
		{
			trigger_error($ex->getMessage(), E_USER_WARNING);
			$this->pdo_conn = null;
			return false;
		}

		if (mt_rand(0, 100) / 100.0 == 1.0)
		{
			$this->purgeOldCodesFromDatabase();
		}

		return $this->pdo_conn;
	}

	protected function getDsn()
	{
		$dsn = sprintf('%s:', $this->database_driver);

		switch ($this->database_driver)
		{
			case self::SI_DRIVER_SQLITE3:
				$dsn .= $this->database_file;
				break;

			case self::SI_DRIVER_MYSQL:
			case self::SI_DRIVER_PGSQL:
				$dsn .= sprintf('host=%s;dbname=%s', $this->database_host, $this->database_name);
				break;

		}

		return $dsn;
	}

	protected function checkTablesExist()
	{
		$table = $this->pdo_conn->quote($this->database_table);

		switch ($this->database_driver)
		{
			case self::SI_DRIVER_SQLITE3:
				// query row count for sqlite, PRAGMA queries seem to return no
				// rowCount using PDO even if there are rows returned
				$query = "SELECT COUNT(id) FROM $table";
				break;

			case self::SI_DRIVER_MYSQL:
				$query = "SHOW TABLES LIKE $table";
				break;

			case self::SI_DRIVER_PGSQL:
				$query = "SELECT * FROM information_schema.columns WHERE table_name = $table;";
				break;
		}

		$result = $this->pdo_conn->query($query);

		if (!$result)
		{
			$err = $this->pdo_conn->errorInfo();

			if ($this->database_driver == self::SI_DRIVER_SQLITE3 && $err[1] === 1 && strpos($err[2], 'no such table') !== false)
			{
				return false;
			}

			throw new Exception("Failed to check tables: {$err[0]} - {$err[1]}: {$err[2]}");
		}
		else if ($this->database_driver == self::SI_DRIVER_SQLITE3)
		{
			// successful here regardless of row count for sqlite
			return true;
		}
		else if ($result->rowCount() == 0)
		{
			return false;
		}
		else
		{
			return true;
		}
	}

	protected function createDatabaseTables()
	{
		$queries = array();

		switch ($this->database_driver)
		{
			case self::SI_DRIVER_SQLITE3:
				$queries[] = "CREATE TABLE \"{$this->database_table}\" (
                                id VARCHAR(40),
                                namespace VARCHAR(32) NOT NULL,
                                code VARCHAR(32) NOT NULL,
                                code_display VARCHAR(32) NOT NULL,
                                created INTEGER NOT NULL,
                                PRIMARY KEY(id, namespace)
                              )";

				$queries[] = "CREATE INDEX ndx_created ON {$this->database_table} (created)";
				break;

			case self::SI_DRIVER_MYSQL:
				$queries[] = "CREATE TABLE `{$this->database_table}` (
                                `id` VARCHAR(40) NOT NULL,
                                `namespace` VARCHAR(32) NOT NULL,
                                `code` VARCHAR(32) NOT NULL,
                                `code_display` VARCHAR(32) NOT NULL,
                                `created` INT NOT NULL,
                                PRIMARY KEY(id, namespace),
                                INDEX(created)
                              )";
				break;

			case self::SI_DRIVER_PGSQL:
				$queries[] = "CREATE TABLE {$this->database_table} (
                                id character varying(40) NOT NULL,
                                namespace character varying(32) NOT NULL,
                                code character varying(32) NOT NULL,
                                code_display character varying(32) NOT NULL,
                                created integer NOT NULL,
                                CONSTRAINT pkey_id_namespace PRIMARY KEY (id, namespace)
                              )";

				$queries[] = "CREATE INDEX ndx_created ON {$this->database_table} (created);";
				break;
		}

		$this->pdo_conn->beginTransaction();

		foreach ($queries as $query)
		{
			$result = $this->pdo_conn->query($query);

			if (!$result)
			{
				$err = $this->pdo_conn->errorInfo();
				trigger_error("Failed to create table.  {$err[1]}: {$err[2]}", E_USER_WARNING);
				$this->pdo_conn->rollBack();
				$this->pdo_conn = false;
				return false;
			}
		}

		$this->pdo_conn->commit();

		return true;
	}

	/**
	 * Get a code from the sqlite database for ip address/captchaId.
	 *
	 * @return string|array Empty string if no code was found or has expired,
	 * otherwise returns the stored captcha code.  If a captchaId is set, this
	 * returns an array with indices "code" and "code_disp"
	 */
	protected function getCodeFromDatabase()
	{
		$code = '';

		if ($this->use_database == true && $this->pdo_conn)
		{
			if (Securimage::$_captchaId !== null)
			{
				$query = "SELECT * FROM {$this->database_table} WHERE id = ?";
				$stmt = $this->pdo_conn->prepare($query);
				$result = $stmt->execute(array(Securimage::$_captchaId));
			}
			else
			{
				$ip = $_SERVER['REMOTE_ADDR'];
				$ns = $this->namespace;

				// ip is stored in id column when no captchaId
				$query = "SELECT * FROM {$this->database_table} WHERE id = ? AND namespace = ?";
				$stmt = $this->pdo_conn->prepare($query);
				$result = $stmt->execute(array($ip, $ns));
			}

			if (!$result)
			{
				$err = $this->pdo_conn->errorInfo();
				trigger_error("Failed to select code from database.  {$err[0]}: {$err[1]}", E_USER_WARNING);
			}
			else
			{
				if (($row = $stmt->fetch()) !== false)
				{
					if (false == $this->isCodeExpired($row['created']))
					{
						if (Securimage::$_captchaId !== null)
						{
							// return an array when using captchaId
							$code = array('code' => $row['code'], 'code_disp' => $row['code_display']);
						}
						else
						{
							$code = $row['code'];
						}
					}
				}
			}
		}

		return $code;
	}

	/**
	 * Remove an entered code from the database
	 */
	protected function clearCodeFromDatabase()
	{
		if ($this->pdo_conn)
		{
			$ip = $_SERVER['REMOTE_ADDR'];
			$ns = $this->pdo_conn->quote($this->namespace);
			$id = Securimage::$_captchaId;

			if (empty($id))
			{
				$id = $ip; // if no captchaId set, IP address is captchaId.
			}

			$id = $this->pdo_conn->quote($id);

			$query = sprintf("DELETE FROM %s WHERE id = %s AND namespace = %s", $this->database_table, $id, $ns);

			$result = $this->pdo_conn->query($query);
			if (!$result)
			{
				trigger_error("Failed to delete code from database.", E_USER_WARNING);
			}
		}
	}

	/**
	 * Deletes old codes from sqlite database
	 */
	protected function purgeOldCodesFromDatabase()
	{
		if ($this->use_database && $this->pdo_conn)
		{
			$now = time();
			$limit = (!is_numeric($this->expiry_time) || $this->expiry_time < 1)?86400:$this->expiry_time;

			$query = sprintf("DELETE FROM %s WHERE %s - created > %s", $this->database_table, $this->pdo_conn->quote($now, PDO::PARAM_INT), $this->pdo_conn->quote($limit, PDO::PARAM_INT));

			$result = $this->pdo_conn->query($query);
		}
	}

	/**
	 * Checks to see if the captcha code has expired and cannot be used
	 * @param unknown_type $creation_time
	 */
	protected function isCodeExpired($creation_time)
	{
		$expired = true;

		if (!is_numeric($this->expiry_time) || $this->expiry_time < 1)
		{
			$expired = false;
		}
		else if (time() - $creation_time < $this->expiry_time)
		{
			$expired = false;
		}

		return $expired;
	}

	/**
	 * Generate a wav file given the $letters in the code
	 * @todo Add ability to merge 2 sound files together to have random background sounds
	 * @param array $letters
	 * @return string The binary contents of the wav file
	 */
	protected function generateWAV($letters)
	{
		$wavCaptcha = new WavFile();
		$first = true; // reading first wav file

		foreach ($letters as $letter)
		{
			$letter = strtoupper($letter);

			try
			{
				$l = new WavFile($this->audio_path . '/' . $letter . '.wav');

				if ($first)
				{
					// set sample rate, bits/sample, and # of channels for file based on first letter
					$wavCaptcha->setSampleRate($l->getSampleRate())->setBitsPerSample($l->getBitsPerSample())->setNumChannels($l->getNumChannels());
					$first = false;
				}

				// append letter to the captcha audio
				$wavCaptcha->appendWav($l);

				// random length of silence between $audio_gap_min and $audio_gap_max
				if ($this->audio_gap_max > 0 && $this->audio_gap_max > $this->audio_gap_min)
				{
					$wavCaptcha->insertSilence(mt_rand($this->audio_gap_min, $this->audio_gap_max) / 1000.0);
				}
			}
			catch (Exception $ex)
			{
				// failed to open file, or the wav file is broken or not supported
				// 2 wav files were not compatible, different # channels, bits/sample, or sample rate
				throw $ex;
			}
		}

		/********* Set up audio filters *****************************/
		$filters = array();

		if ($this->audio_use_noise == true)
		{
			// use background audio - find random file
			$noiseFile = $this->getRandomNoiseFile();

			if ($noiseFile !== false && is_readable($noiseFile))
			{
				try
				{
					$wavNoise = new WavFile($noiseFile, false);
				}
				catch (Exception $ex)
				{
					throw $ex;
				}

				// start at a random offset from the beginning of the wavfile
				// in order to add more randomness
				$randOffset = 0;
				if ($wavNoise->getNumBlocks() > 2 * $wavCaptcha->getNumBlocks())
				{
					$randBlock = mt_rand(0, $wavNoise->getNumBlocks() - $wavCaptcha->getNumBlocks());
					$wavNoise->readWavData($randBlock * $wavNoise->getBlockAlign(), $wavCaptcha->getNumBlocks() * $wavNoise->getBlockAlign());
				}
				else
				{
					$wavNoise->readWavData();
					$randOffset = mt_rand(0, $wavNoise->getNumBlocks() - 1);
				}


				$mixOpts = array('wav' => $wavNoise, 'loop' => true, 'blockOffset' => $randOffset);

				$filters[WavFile::FILTER_MIX] = $mixOpts;
				$filters[WavFile::FILTER_NORMALIZE] = $this->audio_mix_normalization;
			}
		}

		if ($this->degrade_audio == true)
		{
			// add random noise.
			// any noise level below 95% is intensely distorted and not pleasant to the ear
			$filters[WavFile::FILTER_DEGRADE] = mt_rand(95, 98) / 100.0;
		}

		if (!empty($filters))
		{
			$wavCaptcha->filter($filters); // apply filters to captcha audio
		}

		return $wavCaptcha->__toString();
	}

	public function getRandomNoiseFile()
	{
		$return = false;

		if (($dh = opendir($this->audio_noise_path)) !== false)
		{
			$list = array();

			while (($file = readdir($dh)) !== false)
			{
				if ($file == '.' || $file == '..')
					continue;
				if (strtolower(substr($file, -4)) != '.wav')
					continue;

				$list[] = $file;
			}

			closedir($dh);

			if (sizeof($list) > 0)
			{
				$file = $list[array_rand($list, 1)];
				$return = $this->audio_noise_path . DIRECTORY_SEPARATOR . $file;
			}
		}

		return $return;
	}

	/**
	 * Return a wav file saying there was an error generating file
	 *
	 * @return string The binary audio contents
	 */
	protected function audioError()
	{
		return @file_get_contents(dirname(__FILE__) . '/audio/en/error.wav');
	}

	/**
	 * Checks to see if headers can be sent and if any error has been output to the browser
	 *
	 * @return bool true if headers haven't been sent and no output/errors will break audio/images, false if unsafe
	 */
	protected function canSendHeaders()
	{
		if (headers_sent())
		{
			// output has been flushed and headers have already been sent
			return false;
		}
		else if (strlen((string) ob_get_contents()) > 0)
		{
			// headers haven't been sent, but there is data in the buffer that will break image and audio data
			return false;
		}

		return true;
	}

	/**
	 * Return a random float between 0 and 0.9999
	 *
	 * @return float Random float between 0 and 0.9999
	 */
	function frand()
	{
		return 0.0001 * mt_rand(0, 9999);
	}

	/**
	 * Convert an html color code to a Securimage_Color
	 * @param string $color
	 * @param Securimage_Color $default The defalt color to use if $color is invalid
	 */
	protected function initColor($color, $default)
	{
		if ($color == null)
		{
			return new Securimage_Color($default);
		}
		else if (is_string($color))
		{
			try
			{
				return new Securimage_Color($color);
			}
			catch (Exception $e)
			{
				return new Securimage_Color($default);
			}
		}
		else if (is_array($color) && sizeof($color) == 3)
		{
			return new Securimage_Color($color[0], $color[1], $color[2]);
		}
		else
		{
			return new Securimage_Color($default);
		}
	}

	/**
	 * Error handler used when outputting captcha image or audio.
	 * This error handler helps determine if any errors raised would
	 * prevent captcha image or audio from displaying.  If they have
	 * no effect on the output buffer or headers, true is returned so
	 * the script can continue processing.
	 * See https://github.com/dapphp/securimage/issues/15
	 *
	 * @param int $errno
	 * @param string $errstr
	 * @param string $errfile
	 * @param int $errline
	 * @param array $errcontext
	 * @return boolean true if handled, false if PHP should handle
	 */
	public function errorHandler($errno, $errstr, $errfile = '', $errline = 0, $errcontext = array())
	{
		// get the current error reporting level
		$level = error_reporting();

		// if error was supressed or $errno not set in current error level
		if ($level == 0 || ($level & $errno) == 0)
		{
			return true;
		}

		return false;
	}
}


/**
 * Color object for Securimage CAPTCHA
 *
 * @version 3.0
 * @since 2.0
 * @package Securimage
 * @subpackage classes
 *
 */
class Securimage_Color
{
	public $r;
	public $g;
	public $b;

	/**
	 * Create a new Securimage_Color object.<br />
	 * Constructor expects 1 or 3 arguments.<br />
	 * When passing a single argument, specify the color using HTML hex format,<br />
	 * when passing 3 arguments, specify each RGB component (from 0-255) individually.<br />
	 * $color = new Securimage_Color('#0080FF') or <br />
	 * $color = new Securimage_Color(0, 128, 255)
	 *
	 * @param string $color
	 * @throws Exception
	 */
	public function __construct($color = '#ffffff')
	{
		$args = func_get_args();

		if (sizeof($args) == 0)
		{
			$this->r = 255;
			$this->g = 255;
			$this->b = 255;
		}
		else if (sizeof($args) == 1)
		{
			// set based on html code
			if (substr($color, 0, 1) == '#')
			{
				$color = substr($color, 1);
			}

			if (strlen($color) != 3 && strlen($color) != 6)
			{
				throw new InvalidArgumentException('Invalid HTML color code passed to Securimage_Color');
			}

			$this->constructHTML($color);
		}
		else if (sizeof($args) == 3)
		{
			$this->constructRGB($args[0], $args[1], $args[2]);
		}
		else
		{
			throw new InvalidArgumentException('Securimage_Color constructor expects 0, 1 or 3 arguments; ' . sizeof($args) . ' given');
		}
	}

	/**
	 * Construct from an rgb triplet
	 * @param int $red The red component, 0-255
	 * @param int $green The green component, 0-255
	 * @param int $blue The blue component, 0-255
	 */
	protected function constructRGB($red, $green, $blue)
	{
		if ($red < 0)
			$red = 0;
		if ($red > 255)
			$red = 255;
		if ($green < 0)
			$green = 0;
		if ($green > 255)
			$green = 255;
		if ($blue < 0)
			$blue = 0;
		if ($blue > 255)
			$blue = 255;

		$this->r = $red;
		$this->g = $green;
		$this->b = $blue;
	}

	/**
	 * Construct from an html hex color code
	 * @param string $color
	 */
	protected function constructHTML($color)
	{
		if (strlen($color) == 3)
		{
			$red = str_repeat(substr($color, 0, 1), 2);
			$green = str_repeat(substr($color, 1, 1), 2);
			$blue = str_repeat(substr($color, 2, 1), 2);
		}
		else
		{
			$red = substr($color, 0, 2);
			$green = substr($color, 2, 2);
			$blue = substr($color, 4, 2);
		}

		$this->r = hexdec($red);
		$this->g = hexdec($green);
		$this->b = hexdec($blue);
	}
}
