WibySpamBot/securimage_solver/securimage.php

<?php

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

/**
 * Project:  Securimage: A PHP class dealing with CAPTCHA images, audio, and validation
 * File:     securimage.php
 *
 * Copyright (c) 2017, 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.
 *
 * If you found this script useful, please take a quick moment to rate it.
 * 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 2017 Drew Phillips
 * @author Drew Phillips <drew@drew-phillips.com>
 * @version 3.6.6 (Nov 20 2017)
 * @package Securimage
 *
 */

/**

 ChangeLog
 3.6.6
 - Not critical: Fix potential HTML injection in example form via HTTP_USER_AGENT (CVE-2017-14077)

 3.6.5
 - Fix regex in replaceElements in securimage.js
 - Update examples
 - Exclude certain examples from Git autogenerated archives

 3.6.4
 - Fix XSS vulnerability in example_form.ajax.php (Discovered by RedTeam. advisory rt-sa-2016-002)
 - Update example_form.ajax.php to use Securimage::getCaptchaHtml()

 3.6.3
 - Add support for multibyte wordlist files
 - Fix code generation issues with UTF-8 charsets
 - Add parameter to getCaptchaHtml() method to control display components of captcha HTML
 - Fix database audio storage issue with multiple namespaces

 3.6.2
 - Support HTTP range requests with audio playback (iOS requirement)
 - Add optional config.inc.php for storing global configuration settings

 3.6.1
 - Fix copyElement bug in securimage.js for IE Flash fallback

 3.6
 - Implement CAPTCHA audio using HTML5 <audio> with optional Flash fallback
 - Support MP3 audio using LAME MP3 Encoder (Internet Explorer 9+ does not support WAV format in <audio> tags)
 - Add getCaptchaHtml() options to support full framework integration (ruifil)

 3.5.4
 - Fix email validation code in example form files
 - Fix backslashes in getCaptchaHtml for img attribute on Windows systems

 3.5.3
 - Add options for audio button to getCaptchaHtml(), fix urlencoding of flash parameters that was breaking button

 3.5.2

 - Add Securimage::getCaptchaHtml() for getting automatically generated captcha html code
 - Option for using SoX to add effects to captcha audio to make identification by neural networks more difficult
 - Add setNamespace() method
 - Add getTimeToSolve() method
 - Add session_status() check so session still starts if one had previously been opened and closed
 - Add .htaccess file to audio directory to deny access; update audio files
 - Option to skip checking of database tables during connection
 - Add composer.json to package, submit to packagist
 - Add font_ratio variable to determine size of font (github.com/wilkor)
 - Add hint if sqlite3 database is not writeable.  Improve database error handling, add example database options to securimage_play.php
 - Fixed issue regarding database storage and math captcha breaking audio output (github.com/SoftwareAndOutsourcing)

 3.5.1
 - Fix XSS vulnerability in example_form.php (discovered by Gjoko Krstic - <gjoko@zeroscience.mk>)

 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.
 *
 * A class for creating and validating secure CAPTCHA images and audio.
 *
 * The class contains many options regarding appearance, security, storage of
 * captcha data and image/audio generation options.
 *
* @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

    /**
     * Constant for rendering captcha as a JPEG image
     * @var int
     */
    const SI_IMAGE_JPEG = 1;

    /**
     * Constant for rendering captcha as a PNG image (default)
     * @var int
     */

    const SI_IMAGE_PNG  = 2;
    /**
     * Constant for rendering captcha as a GIF image
     * @var int
     */
    const SI_IMAGE_GIF  = 3;

    /**
     * Constant for generating a normal alphanumeric captcha based on the
     * character set
     *
     * @see Securimage::$charset charset property
     * @var int
     */
    const SI_CAPTCHA_STRING     = 0;

    /**
     * Constant for generating a captcha consisting of a simple math problem
     *
     * @var int
     */
    const SI_CAPTCHA_MATHEMATIC = 1;

    /**
     * Constant for generating a word based captcha using 2 words from a list
     *
     * @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';

    /**
     * getCaptchaHtml() display constant for HTML Captcha Image
     *
     * @var integer
     */
    const HTML_IMG   = 1;

    /**
     * getCaptchaHtml() display constant for HTML5 Audio code
     *
     * @var integer
     */
    const HTML_AUDIO = 2;

    /**
     * getCaptchaHtml() display constant for Captcha Input text box
     *
     * @var integer
     */
    const HTML_INPUT = 4;

    /**
     * getCaptchaHtml() display constant for Captcha Text HTML label
     *
     * @var integer
     */
    const HTML_INPUT_LABEL = 8;

    /**
     * getCaptchaHtml() display constant for HTML Refresh button
     *
     * @var integer
     */
    const HTML_ICON_REFRESH = 16;

    /**
     * getCaptchaHtml() display constant for all HTML elements (default)
     *
     * @var integer
     */
    const HTML_ALL = 0xffffffff;

    /*%*********************************************************************%*/
    // 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;

    /**
     * Font size is calculated by image height and this ratio.  Leave blank for
     * default ratio of 0.4.
     *
     * Valid range: 0.1 - 0.99.
     *
     * Depending on image_width, values > 0.6 are probably too large and
     * values < 0.3 are too small.
     *
     * @var float
     */
    public $font_ratio;

    /**
     * The type of the image, default = png
     *
     * @see Securimage::SI_IMAGE_PNG SI_IMAGE_PNG
     * @see Securimage::SI_IMAGE_JPEG SI_IMAGE_JPEG
     * @see Securimage::SI_IMAGE_GIF SI_IMAGE_GIF
     * @var int
     */
    public $image_type   = self::SI_IMAGE_PNG;

    /**
     * The background color of the captcha
     * @var Securimage_Color|string
     */
    public $image_bg_color = '#ffffff';

    /**
     * The color of the captcha text
     * @var Securimage_Color|string
     */
    public $text_color     = '#707070';

    /**
     * The color of the lines over the captcha
     * @var Securimage_Color|string
     */
    public $line_color     = '#707070';

    /**
     * The color of the noise that is drawn
     * @var Securimage_Color|string
     */
    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 or not.
     *
     * 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 be
     * considered incorrect.
     *
     * @var int
     */
    public $expiry_time    = 900;

    /**
     * The session name securimage should use.
     *
     * Only use if your application uses a custom session name (e.g. Joomla).
     * It is recommended to set this value here so it is used by all securimage
     * scripts (i.e. securimage_show.php)
     *
     * @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|string
     */
    public $signature_color = '#707070';

    /**
     * The path to the ttf font file to use for the signature text.
     * Defaults to $ttf_file (AHGBold.ttf)
     *
     * @see Securimage::$ttf_file
     * @var string
     */
    public $signature_font;

    /**
     * No longer used.
     *
     * Use an SQLite database to store data (for users that do not support cookies)
     *
     * @var bool
     * @see Securimage::$database_driver database_driver property
     * @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;

    /**
     * Whether or not to skip checking if Securimage tables exist when using a
     * database.
     *
     * Turn this to true once database functionality is working to improve
     * performance.
     *
     * @var bool true to not check if captcha_codes tables are set up, false
     * to check (and create if necessary)
     */
    public $skip_table_check = 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 == sqlite and does
     * not apply when no database is used, or when using MySQL or PostgreSQL.
     *
     * On *nix, file must have permissions of 0666.
     *
     * **Make sure the directory containing this file is NOT web accessible**
     *
     * @var string
     */
    public $database_file;

    /**
     * The type of captcha to create.
     *
     * Either alphanumeric based on *charset*, a simple math problem, or an
     * image consisting of 2 words from the word list.
     *
     * @see Securimage::SI_CAPTCHA_STRING SI_CAPTCHA_STRING
     * @see Securimage::SI_CAPTCHA_MATHEMATIC SI_CAPTCHA_MATHEMATIC
     * @see Securimage::SI_CAPTCHA_WORDS SI_CAPTCHA_WORDS
     * @see Securimage::$charset charset property
     * @see Securimage::$wordlist_file wordlist_file property
     * @var int
     */
    public $captcha_type  = self::SI_CAPTCHA_STRING; // or self::SI_CAPTCHA_MATHEMATIC, or self::SI_CAPTCHA_WORDS;

    /**
     * The captcha namespace used for having multiple captchas on a page or
     * to separate captchas from differen forms on your site.
     * Example:
     *
     *     <?php
     *     // use <img src="securimage_show.php?namespace=contact_form">
     *     // or manually in securimage_show.php
     *     $img->setNamespace('contact_form');
     *
     *     // in form validator
     *     $img->setNamespace('contact_form');
     *     if ($img->check($code) == true) {
     *         echo "Valid!";
     *     }
     *
     * @var string
     */
    public $namespace;

    /**
     * The TTF 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;

    /**
     * Character encoding of the wordlist file.
     * Requires PHP Multibyte String (mbstring) support.
     * Allows word list to contain characters other than US-ASCII (requires compatible TTF font).
     *
     * @var string The character encoding (e.g. UTF-8, UTF-7, EUC-JP, GB2312)
     * @see http://php.net/manual/en/mbstring.supported-encodings.php
     * @since 3.6.3
     */
    public $wordlist_file_encoding = null;

    /**
     * The directory to scan for background images, if set a random background
     * will be chosen from this folder
     *
     * @var string
     */
    public $background_directory;

    /**
     * No longer used
     *
     * The path to the SQLite database file to use
     *
     * @deprecated 3.2RC4
     * @see Securimage::$database_file database_file property
     * @var string
     */
    public $sqlite_database;

    /**
     * The path to the audio files to be used for audio captchas.
     *
     * Can also be set in securimage_play.php
     *
     * Example:
     *
     *     $img->audio_path = '/home/yoursite/public_html/securimage/audio/en/';
     *
     * @var string
     */
    public $audio_path;

    /**
     * Use SoX (The Swiss Army knife of audio manipulation) for audio effects
     * and processing.
     *
     * Using SoX should make it more difficult for bots to solve audio captchas
     *
     * @see Securimage::$sox_binary_path sox_binary_path property
     * @var bool true to use SoX, false to use PHP
     */
    public $audio_use_sox = false;

    /**
     * The path to the SoX binary on your system
     *
     * @var string
     */
    public $sox_binary_path = '/usr/bin/sox';

    /**
     * The path to the lame (mp3 encoder) binary on your system
     * Static so that Securimage::getCaptchaHtml() has access to this value.
     *
     * @since 3.6
     * @var string
     */
    public static $lame_binary_path = '/usr/bin/lame';

    /**
     * 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
     *
     * 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 audio_noise_path property
     * @var bool true = mix, false = no
     */
    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.
     *
     * Default: 0.6
     *
     * Valid:
     *     >= 1
     *     Normalize by multiplying by the threshold (boost - positive gain).
     *     A value of 1 in effect means no normalization (and results in clipping).
     *
     *     <= -1
     *     Normalize by dividing by the the absolute value of threshold (attenuate - negative gain).
     *     A factor of 2 (-2) is about 6dB reduction in volume.
     *
     *     [0, 1)  (open inverval - not including 1)
     *     The threshold above which amplitudes are comressed logarithmically.
     *     e.g. 0.6 to leave amplitudes up to 60% "as is" and compressabove.
     *
     *     (-1, 0) (open inverval - not including -1 and 0)
     *     The threshold above which amplitudes are comressed linearly.
     *     e.g. -0.6 to leave amplitudes up to 60% "as is" and compress above.
     *
     * @since 3.0.4
     * @var float
     */
    public $audio_mix_normalization = 0.8;

    /**
     * Whether or not to degrade audio by introducing random noise.
     *
     * Current research shows this may not increase the security of audible
     * captchas.
     *
     * 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 = 3000;

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

    /**
     * The GD image resource of the captcha image
     *
     * @var resource
     */
    public $im;

    /**
     * A temporary GD image resource of the captcha image for distortion
     *
     * @var resource
     */
    protected $tmpimg;

    /**
     * The background image GD resource
     * @var string
     */
    protected $bgimg;

    /**
     * Scale factor for magnification of distorted captcha image
     *
     * @var int
     */
    protected $iscale = 5;

    /**
     * Absolute path to securimage directory.
     *
     * This is calculated at runtime
     *
     * @var string
     */
    public $securimage_path = null;

    /**
     * The captcha challenge value.
     *
     * Either the case-sensitive/insensitive word captcha, or the solution to
     * the math captcha.
     *
     * @var string|bool Captcha challenge value
     */
    protected $code;

    /**
     * The display value of the captcha to draw on the image
     *
     * Either 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;

    /**
     * Alternate text to draw as the captcha image text
     *
     * 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;

    /**
     * Time (in seconds) that the captcha was solved in (correctly or incorrectly).
     *
     * This is from the time of code creation, to when validation was attempted.
     *
     * @var int
     */
    protected $_timeToSolve = 0;

    /**
     * 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 PDO|bool
     */
    protected $pdo_conn;

    /**
     * The GD color for the background color
     *
     * @var int
     */
    protected $gdbgcolor;

    /**
     * The GD color for the text color
     *
     * @var int
     */
    protected $gdtextcolor;

    /**
     * The GD color for the line color
     *
     * @var int
     */
    protected $gdlinecolor;

    /**
     * The GD color for the signature text color
     *
     * @var int
     */
    protected $gdsignaturecolor;

    /**
     * Create a new securimage object, pass options to set in the constructor.
     *
     * The object can then be used to display a captcha, play an audible captcha, or validate a submission.
     *
     * @param array $options  Options to initialize the class.  May be any class property.
     *
     *     $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);
     *
     */
    public function __construct($options = array())
    {
        $this->securimage_path = dirname(__FILE__);

        if (!is_array($options)) {
            trigger_error(
                    '$options passed to Securimage::__construct() must be an array.  ' .
                    gettype($options) . ' given',
                    E_USER_WARNING
            );
            $options = array();
        }

        // check for and load settings from custom config file
        if (file_exists(dirname(__FILE__) . '/config.inc.php')) {
            $settings = include dirname(__FILE__) . '/config.inc.php';

            if (is_array($settings)) {
                $options = array_merge($settings, $options);
            }
        }

        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 = true;
        }

        if ($this->no_session != true) {
            // Initialize session or attach to existing
            if ( session_id() == '' || (function_exists('session_status') && PHP_SESSION_NONE == session_status()) ) { // no session has been started yet (or it was previousy closed), which is needed for validation
                if (!is_null($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 (if exists).
     *
     * @param bool $new If true, generates a new challenge and returns and ID.  If false, the existing captcha ID is returned, or null if none exists.
     * @param array $options Additional options to be passed to Securimage.
     *   $options must include database settings if they are not set directly in securimage.php
     *
     * @return null|string Returns null if no captcha id set and new was false, or the captcha ID
     */
    public static function getCaptchaId($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;
        }
    }


    /**
     * Generates a new challenge and serves a captcha image.
     *
     * Appropriate headers will be sent to the browser unless the *send_headers* option is false.
     *
     * @param string $background_image The absolute or relative path to the background image to use as the background of the captcha image.
     *
     *     $img = new Securimage();
     *     $img->code_length = 6;
     *     $img->num_lines   = 5;
     *     $img->noise_level = 5;
     *
     *     $img->show(); // sends the image and appropriate headers to browser
     *     exit;
     */
    public function show($background_image = '')
    {
        set_error_handler(array(&$this, 'errorHandler'));

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

        $this->doImage();
    }

    /**
     * Checks a given code against the correct value from the session and/or database.
     *
     * @param string $code  The captcha code to check
     *
     *     $code = $_POST['code'];
     *     $img  = new Securimage();
     *     if ($img->check($code) == true) {
     *         $captcha_valid = true;
     *     } else {
     *         $captcha_valid = false;
     *     }
     *
     * @return bool true if the given code was correct, false if not.
     */
    public function check($code)
    {
        $this->code_entered = $code;
        $this->validate();
        return $this->correct_code;
    }

    /**
     * Get the time in seconds that it took to solve the captcha.
     *
     * @return int The time in seconds from when the code was created, to when it was solved
     */
    public function getTimeToSolve()
    {
        return $this->_timeToSolve;
    }

    /**
     * Set the namespace for the captcha being stored in the session or database.
     *
     * Namespaces are useful when multiple captchas need to be displayed on a single page.
     *
     * @param string $namespace  Namespace value, String consisting of characters "a-zA-Z0-9_-"
     */
    public function setNamespace($namespace)
    {
        $namespace = preg_replace('/[^a-z0-9-_]/i', '', $namespace);
        $namespace = substr($namespace, 0, 64);

        if (!empty($namespace)) {
            $this->namespace = $namespace;
        } else {
            $this->namespace = 'default';
        }
    }

    /**
     * Return the code from the session or database (if configured).  If none exists or was found, an empty string is returned.
     *
     * @param bool $array  true to receive an array containing the code and properties, false to receive just the code.
     * @param bool $returnExisting If true, and the class property *code* is set, it will be returned instead of getting the code from the session or database.
     * @return array|string Return is an array if $array = true, otherwise a string containing the code
     */
    public function getCode($array = false, $returnExisting = false)
    {
        $code = array();
        $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['code'] = $_SESSION['securimage_code_value'][$this->namespace];
                    $code['time'] = $_SESSION['securimage_code_ctime'][$this->namespace];
                    $code['display'] = $_SESSION['securimage_code_disp'] [$this->namespace];
                }
            }
        }

        if (empty($code) && $this->use_database) {
            // no code in session - may mean user has cookies turned off
            $this->openDatabase();
            $code = $this->getCodeFromDatabase();

            if (!empty($code)) {
                $code['display'] = $code['code_disp'];
                unset($code['code_disp']);
            }
        } else { /* no code stored in session or sqlite database, validation will fail */ }

        if ($array == true) {
            return $code;
        } else {
            return $code['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();
        }
    }

    /**
     * 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
     * @return string|bool
     */
    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;
    }

    /**
     * This method generates a new captcha code.
     *
     * Generates a random captcha code based on *charset*, math problem, or captcha from the wordlist and saves the value to the session and/or database.
     */
    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;
        $ratio   = ($this->font_ratio) ? $this->font_ratio : 0.4;

        if ((float)$ratio < 0.1 || (float)$ratio >= 1) {
            $ratio = 0.4;
        }

        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 * $ratio;
                $bb = imageftbbox($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, $font_size, 0, (int)$x, (int)$y, $this->gdtextcolor, $this->ttf_file, $this->code_display);
            } else {
                $font_size = $this->image_height * $ratio;
                $bb = imageftbbox($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, $font_size, 0, (int)$x, (int)$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;
    }

    /**
     * Generates an audio captcha in WAV format
     *
     * @return string The audio representation of the captcha in Wav format
     */
    protected function getAudibleCode()
    {
        $letters = array();
        $code    = $this->getCode(true, true);

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

        if (empty($code)) {
            $error = 'Failed to get audible code (are database settings correct?).  Check the error log for details';
            trigger_error($error, E_USER_WARNING);
            throw new Exception($error);
        }

        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 file containing a list of words.
     *
     * Seek to a random offset in the file and reads a block of data and returns a line from the file.
     *
     * @param int $numWords Number of words (lines) to read from the file
     * @return string|array|bool  Returns a string if only one word is to be read, or an array of words
     */
    protected function readCodeFromFile($numWords = 1)
    {
        $strpos_func     = 'strpos';
        $strlen_func     = 'strlen';
        $substr_func     = 'substr';
        $strtolower_func = 'strtolower';
        $mb_support      = false;

        if (!empty($this->wordlist_file_encoding)) {
            if (!extension_loaded('mbstring')) {
                trigger_error("wordlist_file_encoding option set, but PHP does not have mbstring support", E_USER_WARNING);
                return false;
            }

            // emits PHP warning if not supported
            $mb_support = mb_internal_encoding($this->wordlist_file_encoding);

            if (!$mb_support) {
                return false;
            }

            $strpos_func     = 'mb_strpos';
            $strlen_func     = 'mb_strlen';
            $substr_func     = 'mb_substr';
            $strtolower_func = 'mb_strtolower';
        }

        $fp = fopen($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 - 128), SEEK_SET); // seek to a random position of file from 0 to filesize-128
            $data = fread($fp, 128); // read a chunk from our random position

            if ($mb_support !== false) {
                $data = mb_ereg_replace("\r?\n", "\n", $data);
            } else {
                $data = preg_replace("/\r?\n/", "\n", $data);
            }

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

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

            $word = $strtolower_func($substr_func($data, $start, $end - $start)); // return a line of the file

            if ($mb_support) {
                // convert to UTF-8 for imagettftext
                $word = mb_convert_encoding($word, 'UTF-8', $this->wordlist_file_encoding);
            }

            $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
     *
     * @see Securimage::$charset  Charset option
     * @return string A randomly generated CAPTCHA code
     */
    protected function generateCode()
    {
        $code = '';

        if (function_exists('mb_strlen')) {
            for($i = 1, $cslen = mb_strlen($this->charset, 'UTF-8'); $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;
    }

    /**
     * Validate a code supplied by the user
     *
     * Checks the entered code against the value stored in the session and/or database (if configured).  Handles case sensitivity.
     * Also removes the code from session/database if the code was entered correctly to prevent re-use attack.
     *
     * This function does not return a value.
     *
     * @see Securimage::$correct_code 'correct_code' property
     */
    protected function validate()
    {
        if (!is_string($this->code) || strlen($this->code) == 0) {
            $code = $this->getCode(true);
            // 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 (is_array($code)) {
            if (!empty($code)) {
                $ctime = $code['time'];
                $code  = $code['code'];

                $this->_timeToSolve = time() - $ctime;
            } else {
                $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 ((string)$code === (string)$code_entered) {
                $this->correct_code = true;
                if ($this->no_session != true) {
                    $_SESSION['securimage_code_disp'] [$this->namespace] = '';
                    $_SESSION['securimage_code_value'][$this->namespace] = '';
                    $_SESSION['securimage_code_ctime'][$this->namespace] = '';
                    $_SESSION['securimage_code_audio'][$this->namespace] = '';
                }
                $this->clearCodeFromDatabase();
            }
        }
    }

    /**
     * Save CAPTCHA data to session and database (if configured)
     */
    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();
            $_SESSION['securimage_code_audio'][$this->namespace] = null; // clear previous audio, if set
        }

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

    /**
     * Checks to see if the captcha code has expired and can no longer be used.
     *
     * @see Securimage::$expiry_time expiry_time
     * @param int $creation_time  The Unix timestamp of when the captcha code was created
     * @return bool true if the code is expired, false if it is still valid
     */
    protected function isCodeExpired($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;
    }

    /**
     * Checks to see if headers can be sent and if any error has been output
     * to the browser
     *
     * @return bool true if it is safe to send headers, false if not
     */
    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|string $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);
        }
    }

    /**
     * The error handling function 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  PHP error number
     * @param string $errstr  String description of the error
     * @param string $errfile  File error occurred in
     * @param int $errline  Line the error occurred on in file
     * @param array $errcontext  Additional context information
     * @return boolean true if the error was handled, false if PHP should handle the error
     */
    public function errorHandler($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
 *
* @since 2.0
 * @package Securimage
 * @subpackage classes
 *
 */
class Securimage_Color
{
    /**
     * Red value (0-255)
     * @var int
     */
    public $r;

    /**
     * Gree value (0-255)
     * @var int
     */
    public $g;

    /**
     * Blue value (0-255)
     * @var int
     */
    public $b;

    /**
     * Create a new Securimage_Color object.
     *
     * Constructor expects 1 or 3 arguments.
     *
     * When passing a single argument, specify the color using HTML hex format.
     *
     * When passing 3 arguments, specify each RGB component (from 0-255)
     * individually.
     *
     * Examples:
     *
     *     $color = new Securimage_Color('#0080FF');
     *     $color = new Securimage_Color(0, 128, 255);
     *
     * @param string $color  The html color code to use
     * @throws Exception  If any color value is not valid
     */
    public function __construct($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);
    }
}