From 8df3db566a3a937b45ebf11adb90d265e6f5e2d4 Mon Sep 17 00:00:00 2001
From: Andreas Baumann <mail@andreasbaumann.cc>
Date: Sun, 17 Nov 2019 20:45:02 +0100
Subject: initial checking of customized version 1.0rc9

---
 vendor/dapphp/securimage/securimage.php | 3468 +++++++++++++++++++++++++++++++
 1 file changed, 3468 insertions(+)
 create mode 100644 vendor/dapphp/securimage/securimage.php

(limited to 'vendor/dapphp/securimage/securimage.php')

diff --git a/vendor/dapphp/securimage/securimage.php b/vendor/dapphp/securimage/securimage.php
new file mode 100644
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--- /dev/null
+++ b/vendor/dapphp/securimage/securimage.php
@@ -0,0 +1,3468 @@
+<?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
+     */
+    protected $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;
+    }
+
+    /**
+     * Returns HTML code for displaying the captcha image, audio button, and form text input.
+     *
+     * Options can be specified to modify the output of the HTML.  Accepted options:
+     *
+     *     'securimage_path':
+     *         Optional: The URI to where securimage is installed (e.g. /securimage)
+     *     'show_image_url':
+     *         Path to the securimage_show.php script (useful when integrating with a framework or moving outside the securimage directory)
+     *         This will be passed as a urlencoded string to the <img> tag for outputting the captcha image
+     *     'audio_play_url':
+     *         Same as show_image_url, except this indicates the URL of the audio playback script
+     *     'image_id':
+     *          A string that sets the "id" attribute of the captcha image (default: captcha_image)
+     *     'image_alt_text':
+     *         The alt text of the captcha image (default: CAPTCHA Image)
+     *     'show_audio_button':
+     *         true/false  Whether or not to show the audio button (default: true)
+     *     'disable_flash_fallback':)
+     *         Allow only HTML5 audio and disable Flash fallback
+     *     'show_refresh_button':
+     *         true/false  Whether or not to show a button to refresh the image (default: true)
+     *     'audio_icon_url':
+     *         URL to the image used for showing the HTML5 audio icon
+     *     'icon_size':
+     *         Size (for both height & width) in pixels of the audio and refresh buttons
+     *     'show_text_input':
+     *         true/false  Whether or not to show the text input for the captcha (default: true)
+     *     'refresh_alt_text':
+     *         Alt text for the refresh image (default: Refresh Image)
+     *     'refresh_title_text':
+     *         Title text for the refresh image link (default: Refresh Image)
+     *     'input_id':
+     *         A string that sets the "id" attribute of the captcha text input (default: captcha_code)
+     *     'input_name':
+     *         A string that sets the "name" attribute of the captcha text input (default: same as input_id)
+     *     'input_text':
+     *         A string that sets the text of the label for the captcha text input (default: Type the text:)
+     *     'input_attributes':
+     *         An array of additional HTML tag attributes to pass to the text input tag (default: empty)
+     *     'image_attributes':
+     *         An array of additional HTML tag attributes to pass to the captcha image tag (default: empty)
+     *     'error_html':
+     *         Optional HTML markup to be shown above the text input field
+     *     'namespace':
+     *         The optional captcha namespace to use for showing the image and playing back the audio. Namespaces are for using multiple captchas on the same page.
+     *
+     * @param array $options Array of options for modifying the HTML code.
+     * @param int   $parts Securiage::HTML_* constant controlling what component of the captcha HTML to display
+     *
+     * @return string  The generated HTML code for displaying the captcha
+     */
+    public static function getCaptchaHtml($options = array(), $parts = Securimage::HTML_ALL)
+    {
+        static $javascript_init = false;
+
+        if (!isset($options['securimage_path'])) {
+            $docroot = (isset($_SERVER['DOCUMENT_ROOT'])) ? $_SERVER['DOCUMENT_ROOT'] : substr($_SERVER['SCRIPT_FILENAME'], 0, -strlen($_SERVER['SCRIPT_NAME']));
+            $docroot = realpath($docroot);
+            $sipath  = dirname(__FILE__);
+            $securimage_path = str_replace($docroot, '', $sipath);
+        } else {
+            $securimage_path = $options['securimage_path'];
+        }
+
+        $show_image_url    = (isset($options['show_image_url'])) ? $options['show_image_url'] : null;
+        $image_id          = (isset($options['image_id'])) ? $options['image_id'] : 'captcha_image';
+        $image_alt         = (isset($options['image_alt_text'])) ? $options['image_alt_text'] : 'CAPTCHA Image';
+        $show_audio_btn    = (isset($options['show_audio_button'])) ? (bool)$options['show_audio_button'] : true;
+        $disable_flash_fbk = (isset($options['disable_flash_fallback'])) ? (bool)$options['disable_flash_fallback'] : false;
+        $show_refresh_btn  = (isset($options['show_refresh_button'])) ? (bool)$options['show_refresh_button'] : true;
+        $refresh_icon_url  = (isset($options['refresh_icon_url'])) ? $options['refresh_icon_url'] : null;
+        $audio_but_bg_col  = (isset($options['audio_button_bgcol'])) ? $options['audio_button_bgcol'] : '#ffffff';
+        $audio_icon_url    = (isset($options['audio_icon_url'])) ? $options['audio_icon_url'] : null;
+        $loading_icon_url  = (isset($options['loading_icon_url'])) ? $options['loading_icon_url'] : null;
+        $icon_size         = (isset($options['icon_size'])) ? $options['icon_size'] : 32;
+        $audio_play_url    = (isset($options['audio_play_url'])) ? $options['audio_play_url'] : null;
+        $audio_swf_url     = (isset($options['audio_swf_url'])) ? $options['audio_swf_url'] : null;
+        $show_input        = (isset($options['show_text_input'])) ? (bool)$options['show_text_input'] : true;
+        $refresh_alt       = (isset($options['refresh_alt_text'])) ? $options['refresh_alt_text'] : 'Refresh Image';
+        $refresh_title     = (isset($options['refresh_title_text'])) ? $options['refresh_title_text'] : 'Refresh Image';
+        $input_text        = (isset($options['input_text'])) ? $options['input_text'] : 'Type the text:';
+        $input_id          = (isset($options['input_id'])) ? $options['input_id'] : 'captcha_code';
+        $input_name        = (isset($options['input_name'])) ? $options['input_name'] :  $input_id;
+        $input_attrs       = (isset($options['input_attributes'])) ? $options['input_attributes'] : array();
+        $image_attrs       = (isset($options['image_attributes'])) ? $options['image_attributes'] : array();
+        $error_html        = (isset($options['error_html'])) ? $options['error_html'] : null;
+        $namespace         = (isset($options['namespace'])) ? $options['namespace'] : '';
+
+        $rand              = md5(uniqid($_SERVER['REMOTE_PORT'], true));
+        $securimage_path   = rtrim($securimage_path, '/\\');
+        $securimage_path   = str_replace('\\', '/', $securimage_path);
+
+        $image_attr = '';
+        if (!is_array($image_attrs)) $image_attrs = array();
+        if (!isset($image_attrs['style'])) $image_attrs['style'] = 'float: left; padding-right: 5px';
+        $image_attrs['id']  = $image_id;
+
+        $show_path = $securimage_path . '/securimage_show.php?';
+        if ($show_image_url) {
+            if (parse_url($show_image_url, PHP_URL_QUERY)) {
+                $show_path = "{$show_image_url}&";
+            } else {
+                $show_path = "{$show_image_url}?";
+            }
+        }
+        if (!empty($namespace)) {
+            $show_path .= sprintf('namespace=%s&amp;', $namespace);
+        }
+        $image_attrs['src'] = $show_path . $rand;
+
+        $image_attrs['alt'] = $image_alt;
+
+        foreach($image_attrs as $name => $val) {
+            $image_attr .= sprintf('%s="%s" ', $name, htmlspecialchars($val));
+        }
+
+        $swf_path  = $securimage_path . '/securimage_play.swf';
+        $play_path = $securimage_path . '/securimage_play.php?';
+        $icon_path = $securimage_path . '/images/audio_icon.png';
+        $load_path = $securimage_path . '/images/loading.png';
+        $js_path   = $securimage_path . '/securimage.js';
+
+        if (!empty($audio_icon_url)) {
+            $icon_path = $audio_icon_url;
+        }
+
+        if (!empty($loading_icon_url)) {
+            $load_path = $loading_icon_url;
+        }
+
+        if (!empty($audio_play_url)) {
+            if (parse_url($audio_play_url, PHP_URL_QUERY)) {
+                $play_path = "{$audio_play_url}&";
+            } else {
+                $play_path = "{$audio_play_url}?";
+            }
+        }
+
+        if (!empty($namespace)) {
+            $play_path .= sprintf('namespace=%s&amp;', $namespace);
+        }
+
+        if (!empty($audio_swf_url)) {
+            $swf_path = $audio_swf_url;
+        }
+
+        $audio_obj = $image_id . '_audioObj';
+        $html      = '';
+
+        if ( ($parts & Securimage::HTML_IMG) > 0) {
+            $html .= sprintf('<img %s/>', $image_attr);
+        }
+
+        if ( ($parts & Securimage::HTML_AUDIO) > 0 && $show_audio_btn) {
+            // html5 audio
+            $html .= sprintf('<div id="%s_audio_div">', $image_id) . "\n" .
+                     sprintf('<audio id="%s_audio" preload="none" style="display: none">', $image_id) . "\n";
+
+            // check for existence and executability of LAME binary
+            // prefer mp3 over wav by sourcing it first, if available
+            if (is_executable(Securimage::$lame_binary_path)) {
+                $html .= sprintf('<source id="%s_source_mp3" src="%sid=%s&amp;format=mp3" type="audio/mpeg">', $image_id, $play_path, uniqid()) . "\n";
+            }
+
+            // output wav source
+            $html .= sprintf('<source id="%s_source_wav" src="%sid=%s" type="audio/wav">', $image_id, $play_path, uniqid()) . "\n";
+
+            // flash audio button
+            if (!$disable_flash_fbk) {
+                $html .= sprintf('<object type="application/x-shockwave-flash" data="%s?bgcol=%s&amp;icon_file=%s&amp;audio_file=%s" height="%d" width="%d">',
+                        htmlspecialchars($swf_path),
+                        urlencode($audio_but_bg_col),
+                        urlencode($icon_path),
+                        urlencode(html_entity_decode($play_path)),
+                        $icon_size, $icon_size
+                );
+
+                $html .= sprintf('<param name="movie" value="%s?bgcol=%s&amp;icon_file=%s&amp;audio_file=%s" />',
+                        htmlspecialchars($swf_path),
+                        urlencode($audio_but_bg_col),
+                        urlencode($icon_path),
+                        urlencode(html_entity_decode($play_path))
+                );
+
+                $html .= '</object><br />';
+            }
+
+            // html5 audio close
+            $html .= "</audio>\n</div>\n";
+
+            // html5 audio controls
+            $html .= sprintf('<div id="%s_audio_controls">', $image_id) . "\n" .
+                     sprintf('<a tabindex="-1" class="captcha_play_button" href="%sid=%s" onclick="return false">',
+                             $play_path, uniqid()
+                     ) . "\n" .
+                     sprintf('<img class="captcha_play_image" height="%d" width="%d" src="%s" alt="Play CAPTCHA Audio" style="border: 0px">', $icon_size, $icon_size, htmlspecialchars($icon_path)) . "\n" .
+                     sprintf('<img class="captcha_loading_image rotating" height="%d" width="%d" src="%s" alt="Loading audio" style="display: none">', $icon_size, $icon_size, htmlspecialchars($load_path)) . "\n" .
+                     "</a>\n<noscript>Enable Javascript for audio controls</noscript>\n" .
+                     "</div>\n";
+
+            // html5 javascript
+            if (!$javascript_init) {
+                $html .= sprintf('<script type="text/javascript" src="%s"></script>', $js_path) . "\n";
+                $javascript_init = true;
+            }
+            $html .= '<script type="text/javascript">' .
+                     "$audio_obj = new SecurimageAudio({ audioElement: '{$image_id}_audio', controlsElement: '{$image_id}_audio_controls' });" .
+                     "</script>\n";
+        }
+
+        if ( ($parts & Securimage::HTML_ICON_REFRESH) > 0 && $show_refresh_btn) {
+            $icon_path = $securimage_path . '/images/refresh.png';
+            if ($refresh_icon_url) {
+                $icon_path = $refresh_icon_url;
+            }
+            $img_tag = sprintf('<img height="%d" width="%d" src="%s" alt="%s" onclick="this.blur()" style="border: 0px; vertical-align: bottom" />',
+                               $icon_size, $icon_size, htmlspecialchars($icon_path), htmlspecialchars($refresh_alt));
+
+            $html .= sprintf('<a tabindex="-1" style="border: 0" href="#" title="%s" onclick="%sdocument.getElementById(\'%s\').src = \'%s\' + Math.random(); this.blur(); return false">%s</a><br />',
+                    htmlspecialchars($refresh_title),
+                    ($audio_obj) ? "if (typeof window.{$audio_obj} !== 'undefined') {$audio_obj}.refresh(); " : '',
+                    $image_id,
+                    $show_path,
+                    $img_tag
+            );
+        }
+
+        if ($parts == Securimage::HTML_ALL) {
+            $html .= '<div style="clear: both"></div>';
+        }
+
+        if ( ($parts & Securimage::HTML_INPUT_LABEL) > 0 && $show_input) {
+            $html .= sprintf('<label for="%s">%s</label> ',
+                    htmlspecialchars($input_id),
+                    htmlspecialchars($input_text));
+
+            if (!empty($error_html)) {
+                $html .= $error_html;
+            }
+        }
+
+        if ( ($parts & Securimage::HTML_INPUT) > 0 && $show_input) {
+            $input_attr = '';
+            if (!is_array($input_attrs)) $input_attrs = array();
+            $input_attrs['type'] = 'text';
+            $input_attrs['name'] = $input_name;
+            $input_attrs['id']   = $input_id;
+
+            foreach($input_attrs as $name => $val) {
+                $input_attr .= sprintf('%s="%s" ', $name, htmlspecialchars($val));
+            }
+
+            $html .= sprintf('<input %s/>', $input_attr);
+        }
+
+        return $html;
+    }
+
+    /**
+     * 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';
+        }
+    }
+
+    /**
+     * Generate an audible captcha in WAV format and send it to the browser with appropriate headers.
+     * Example:
+     *
+     *     $img = new Securimage();
+     *     $img->outputAudioFile(); // outputs a wav file to the browser
+     *     exit;
+     *
+     * @param string $format
+     */
+    public function outputAudioFile($format = null)
+    {
+        set_error_handler(array(&$this, 'errorHandler'));
+
+        if (isset($_SERVER['HTTP_RANGE'])) {
+            $range   = true;
+            $rangeId = (isset($_SERVER['HTTP_X_PLAYBACK_SESSION_ID'])) ?
+                       'ID' . $_SERVER['HTTP_X_PLAYBACK_SESSION_ID']   :
+                       'ID' . md5($_SERVER['REQUEST_URI']);
+            $uniq    = $rangeId;
+        } else {
+            $uniq = md5(uniqid(microtime()));
+        }
+
+        try {
+            if (!($audio = $this->getAudioData())) {
+                // if previously generated audio not found for current captcha
+                require_once dirname(__FILE__) . '/WavFile.php';
+                $audio = $this->getAudibleCode();
+
+                if (strtolower($format) == 'mp3') {
+                    $audio = $this->wavToMp3($audio);
+                }
+
+                $this->saveAudioData($audio);
+            }
+        } 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->no_session != true) {
+            // close session to make it available to other requests in the event
+            // streaming the audio takes sevaral seconds or more
+            session_write_close();
+        }
+
+        if ($this->canSendHeaders() || $this->send_headers == false) {
+            if ($this->send_headers) {
+                if ($format == 'mp3') {
+                    $ext  = 'mp3';
+                    $type = 'audio/mpeg';
+                } else {
+                    $ext  = 'wav';
+                    $type = 'audio/wav';
+                }
+
+                header('Accept-Ranges: bytes');
+                header("Content-Disposition: attachment; filename=\"securimage_audio-{$uniq}.{$ext}\"");
+                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: ' . $type);
+            }
+
+            $this->rangeDownload($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;
+    }
+
+    /**
+     * Output audio data with http range support.  Typically this shouldn't be
+     * called directly unless being used with a custom implentation.  Use
+     * Securimage::outputAudioFile instead.
+     *
+     * @param string $audio Raw wav or mp3 audio file content
+     */
+    public function rangeDownload($audio)
+    {
+        /* Congratulations Firefox Android/Linux/Windows for being the most
+         * sensible browser of all when streaming HTML5 audio!
+         *
+         * Chrome on Android and iOS on iPad/iPhone both make extra HTTP requests
+         * for the audio whether on WiFi or the mobile network resulting in
+         * multiple downloads of the audio file and wasted bandwidth.
+         *
+         * If I'm doing something wrong in this code or anyone knows why, I'd
+         * love to hear from you.
+         */
+        $audioLength = $size = strlen($audio);
+
+        if (isset($_SERVER['HTTP_RANGE'])) {
+            list( , $range) = explode('=', $_SERVER['HTTP_RANGE']); // bytes=byte-range-set
+            $range = trim($range);
+
+            if (strpos($range, ',') !== false) {
+                // eventually, we should handle requests with multiple ranges
+                // most likely these types of requests will never be sent
+                header('HTTP/1.1 416 Range Not Satisfiable');
+                echo "<h1>Range Not Satisfiable</h1>";
+                exit;
+            } else if (preg_match('/(\d+)-(\d+)/', $range, $match)) {
+                // bytes n - m
+                $range = array(intval($match[1]), intval($match[2]));
+            } else if (preg_match('/(\d+)-$/', $range, $match)) {
+                // bytes n - last byte of file
+                $range = array(intval($match[1]), null);
+            } else if (preg_match('/-(\d+)/', $range, $match)) {
+                // final n bytes of file
+                $range = array($size - intval($match[1]), $size - 1);
+            }
+
+            if ($range[1] === null) $range[1] = $size - 1;
+            $length = $range[1] - $range[0] + 1;
+            $audio = substr($audio, $range[0], $length);
+            $audioLength = strlen($audio);
+
+            header('HTTP/1.1 206 Partial Content');
+            header("Content-Range: bytes {$range[0]}-{$range[1]}/{$size}");
+
+            if ($range[0] < 0 ||$range[1] >= $size || $range[0] >= $size || $range[0] > $range[1]) {
+                header('HTTP/1.1 416 Range Not Satisfiable');
+                echo "<h1>Range Not Satisfiable</h1>";
+                exit;
+            }
+        }
+
+        header('Content-Length: ' . $audioLength);
+
+        echo $audio;
+    }
+
+    /**
+     * 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();
+        }
+
+        $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
+     * @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();
+        }
+    }
+
+    /**
+     * Save audio data to session and/or the configured database
+     *
+     * @param string $data The CAPTCHA audio data
+     */
+    protected function saveAudioData($data)
+    {
+        if ($this->no_session != true) {
+            $_SESSION['securimage_code_audio'][$this->namespace] = $data;
+        }
+
+        if ($this->use_database) {
+            $this->saveAudioToDatabase($data);
+        }
+    }
+
+    /**
+     * Gets audio file contents from the session or database
+     *
+     * @return string|boolean Audio contents on success, or false if no audio found in session or DB
+     */
+    protected function getAudioData()
+    {
+        if ($this->no_session != true) {
+            if (isset($_SESSION['securimage_code_audio'][$this->namespace])) {
+                return $_SESSION['securimage_code_audio'][$this->namespace];
+            }
+        }
+
+        if ($this->use_database) {
+            $this->openDatabase();
+            $code = $this->getCodeFromDatabase();
+
+            if (!empty($code['audio_data'])) {
+                return $code['audio_data'];
+            }
+        }
+
+        return false;
+    }
+
+    /**
+     * Saves the CAPTCHA data to the configured 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)
+            // Clears previous captcha for this client from database so we can do a straight insert
+            // without having to do INSERT ... ON DUPLICATE KEY or a find/update
+            $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();
+                $error = "Failed to insert code into database. {$err[1]}: {$err[2]}.";
+
+                if ($this->database_driver == self::SI_DRIVER_SQLITE3) {
+                    $err14 = ($err[1] == 14);
+                    if ($err14) $error .= sprintf(" Ensure database directory and file are writeable by user '%s' (%d).",
+                                                   get_current_user(), getmyuid());
+                }
+
+                trigger_error($error, E_USER_WARNING);
+            }
+        }
+
+        return $success !== false;
+    }
+
+    /**
+     * Saves CAPTCHA audio to the configured database
+     *
+     * @param string $data Audio data
+     * @return boolean true on success, false on failure
+     */
+    protected function saveAudioToDatabase($data)
+    {
+        $success = false;
+        $this->openDatabase();
+
+        if ($this->use_database && $this->pdo_conn) {
+            $id = $this->getCaptchaId(false);
+            $ip = $_SERVER['REMOTE_ADDR'];
+            $ns = $this->namespace;
+
+            if (empty($id)) {
+                $id = $ip;
+            }
+
+            $query = "UPDATE {$this->database_table} SET audio_data = :audioData WHERE id = :id AND namespace = :namespace";
+            $stmt  = $this->pdo_conn->prepare($query);
+            $stmt->bindParam(':audioData', $data, PDO::PARAM_LOB);
+            $stmt->bindParam(':id', $id);
+            $stmt->bindParam(':namespace', $ns);
+            $success = $stmt->execute();
+        }
+
+        return $success !== false;
+    }
+
+    /**
+     * Opens a connection to the configured database.
+     *
+     * @see Securimage::$use_database Use database
+     * @see Securimage::$database_driver Database driver
+     * @see Securimage::$pdo_conn pdo_conn
+     * @return bool true if the database connection was successful, false if not
+     */
+    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;
+            }
+        }
+
+        try {
+            $dsn = $this->getDsn();
+
+            $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;
+        } catch (Exception $ex) {
+            trigger_error($ex->getMessage(), E_USER_WARNING);
+            return false;
+        }
+
+        try {
+            if (!$this->skip_table_check && !$this->checkTablesExist()) {
+                // create tables...
+                $this->createDatabaseTables();
+            }
+        } catch (Exception $ex) {
+            trigger_error($ex->getMessage(), E_USER_WARNING);
+            $this->pdo_conn = false;
+            return false;
+        }
+
+        if (mt_rand(0, 100) / 100.0 == 1.0) {
+            $this->purgeOldCodesFromDatabase();
+        }
+
+        return $this->pdo_conn;
+    }
+
+    /**
+     * Get the PDO DSN string for connecting to the database
+     *
+     * @see Securimage::$database_driver Database driver
+     * @throws Exception  If database specific options are not configured
+     * @return string     The DSN for connecting to the database
+     */
+    protected function getDsn()
+    {
+        $dsn = sprintf('%s:', $this->database_driver);
+
+        switch($this->database_driver) {
+            case self::SI_DRIVER_SQLITE3:
+                $dsn .= $this->database_file;
+                break;
+
+            case self::SI_DRIVER_MYSQL:
+            case self::SI_DRIVER_PGSQL:
+                if (empty($this->database_host)) {
+                    throw new Exception('Securimage::database_host is not set');
+                } else if (empty($this->database_name)) {
+                    throw new Exception('Securimage::database_name is not set');
+                }
+
+                $dsn .= sprintf('host=%s;dbname=%s',
+                                $this->database_host,
+                                $this->database_name);
+                break;
+
+        }
+
+        return $dsn;
+    }
+
+    /**
+     * Checks if the necessary database tables for storing captcha codes exist
+     *
+     * @throws Exception If the table check failed for some reason
+     * @return boolean true if the database do exist, false if not
+     */
+    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 ($result->rowCount() == 0) {
+            return false;
+        } else {
+            return true;
+        }
+    }
+
+    /**
+     * Create the necessary databaes table for storing captcha codes.
+     *
+     * Based on the database adapter used, the tables will created in the existing connection.
+     *
+     * @see Securimage::$database_driver Database driver
+     * @return boolean true if the tables were created, false if not
+     */
+    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,
+                                audio_data BLOB 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,
+                                `audio_data` MEDIUMBLOB 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,
+                                audio_data bytea 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;
+    }
+
+    /**
+     * Retrieves a stored code from the database for based on the captchaId or
+     * IP address if captcha ID not used.
+     *
+     * @return string|array Empty string if no code was found or has expired,
+     * otherwise returns array of code information.
+     */
+    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 ($this->database_driver == self::SI_DRIVER_PGSQL && is_resource($row['audio_data'])) {
+                            // pg bytea data returned as stream resource
+                            $data = '';
+                            while (!feof($row['audio_data'])) {
+                                $data .= fgets($row['audio_data']);
+                            }
+                            $row['audio_data'] = $data;
+                        }
+                        $code = array(
+                            'code'      => $row['code'],
+                            'code_disp' => $row['code_display'],
+                            'time'      => $row['created'],
+                            'audio_data' => $row['audio_data'],
+                        );
+                    }
+                }
+            }
+        }
+
+        return $code;
+    }
+
+    /**
+     * Remove a stored code from the database based on captchaId or IP address.
+     */
+    protected function clearCodeFromDatabase()
+    {
+        if ($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 (!$result) {
+                trigger_error("Failed to delete code from database.", E_USER_WARNING);
+            }
+        }
+    }
+
+    /**
+     * Deletes old (expired) codes from the database
+     */
+    protected function purgeOldCodesFromDatabase()
+    {
+        if ($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,
+                             $now,
+                             $this->pdo_conn->quote("$limit", PDO::PARAM_INT));
+
+            $result = $this->pdo_conn->query($query);
+        }
+    }
+
+    /**
+     * 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;
+    }
+
+    /**
+     * Generate a wav file given the $letters in the code
+     *
+     * @param array $letters  The letters making up the captcha
+     * @return string The audio content in WAV format
+     */
+    protected function generateWAV($letters)
+    {
+        $wavCaptcha = new WavFile();
+        $first      = true;     // reading first wav file
+
+        if ($this->audio_use_sox && !is_executable($this->sox_binary_path)) {
+            throw new Exception("Path to SoX binary is incorrect or not executable");
+        }
+
+        foreach ($letters as $letter) {
+            $letter = strtoupper($letter);
+
+            try {
+                $letter_file = realpath($this->audio_path) . DIRECTORY_SEPARATOR . $letter . '.wav';
+
+                if ($this->audio_use_sox) {
+                    $sox_cmd = sprintf("%s %s -t wav - %s",
+                                       $this->sox_binary_path,
+                                       $letter_file,
+                                       $this->getSoxEffectChain());
+
+                    $data = `$sox_cmd`;
+
+                    $l = new WavFile();
+                    $l->setIgnoreChunkSizes(true);
+                    $l->setWavData($data);
+                } else {
+                    $l = new WavFile($letter_file);
+                }
+
+                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 $ex) {
+                // failed to open file, or the wav file is broken or not supported
+                // 2 wav files were not compatible, different # channels, bits/sample, or sample rate
+                throw new Exception("Error generating audio captcha on letter '$letter': " . $ex->getMessage());
+            }
+        }
+
+        /********* Set up audio filters *****************************/
+        $filters = array();
+
+        if ($this->audio_use_noise == true) {
+            // use background audio - find random file
+            $wavNoise   = false;
+            $randOffset = 0;
+
+            /*
+            // uncomment to try experimental SoX noise generation.
+            // warning: sounds may be considered annoying
+            if ($this->audio_use_sox) {
+                $duration = $wavCaptcha->getDataSize() / ($wavCaptcha->getBitsPerSample() / 8) /
+                            $wavCaptcha->getNumChannels() / $wavCaptcha->getSampleRate();
+                $duration = round($duration, 2);
+                $wavNoise = new WavFile();
+                $wavNoise->setIgnoreChunkSizes(true);
+                $noiseData = $this->getSoxNoiseData($duration,
+                                                    $wavCaptcha->getNumChannels(),
+                                                    $wavCaptcha->getSampleRate(),
+                                                    $wavCaptcha->getBitsPerSample());
+                $wavNoise->setWavData($noiseData, true);
+
+            } else
+            */
+            if ( ($noiseFile = $this->getRandomNoiseFile()) !== false) {
+                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, $wavNoise->getNumBlocks() - 1);
+                }
+            }
+
+            if ($wavNoise !== false) {
+                $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();
+    }
+
+    /**
+     * Gets and returns the path to a random noise file from the audio noise directory.
+     *
+     * @return bool|string  false if a file could not be found, or a string containing the path to the file.
+     */
+    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 . $file;
+
+                if (!is_readable($return)) $return = false;
+            }
+        }
+
+        return $return;
+    }
+
+    /**
+     * Get a random effect or chain of effects to apply to a segment of the
+     * audio file.
+     *
+     * These effects should increase the randomness of the audio for
+     * a particular letter/number by modulating the signal.  The SoX effects
+     * used are *bend*, *chorus*, *overdrive*, *pitch*, *reverb*, *tempo*, and
+     * *tremolo*.
+     *
+     * For each effect selected, random parameters are supplied to the effect.
+     *
+     * @param int $numEffects  How many effects to chain together
+     * @return string  A string of valid SoX effects and their respective options.
+     */
+    protected function getSoxEffectChain($numEffects = 2)
+    {
+        $effectsList = array('bend', 'chorus', 'overdrive', 'pitch', 'reverb', 'tempo', 'tremolo');
+        $effects     = array_rand($effectsList, $numEffects);
+        $outEffects  = array();
+
+        if (!is_array($effects)) $effects = array($effects);
+
+        foreach($effects as $effect) {
+            $effect = $effectsList[$effect];
+
+            switch($effect)
+            {
+                case 'bend':
+                    $delay = mt_rand(0, 15) / 100.0;
+                    $cents = mt_rand(-120, 120);
+                    $dur   = mt_rand(75, 400) / 100.0;
+                    $outEffects[] = "$effect $delay,$cents,$dur";
+                    break;
+
+                case 'chorus':
+                    $gainIn  = mt_rand(75, 90) / 100.0;
+                    $gainOut = mt_rand(70, 95) / 100.0;
+                    $chorStr = "$effect $gainIn $gainOut";
+
+                    for ($i = 0; $i < mt_rand(2, 3); ++$i) {
+                        $delay = mt_rand(20, 100);
+                        $decay = mt_rand(10, 100) / 100.0;
+                        $speed = mt_rand(20, 50) / 100.0;
+                        $depth = mt_rand(150, 250) / 100.0;
+
+                        $chorStr .= " $delay $decay $speed $depth -s";
+                    }
+
+                    $outEffects[] = $chorStr;
+                    break;
+
+                case 'overdrive':
+                    $gain = mt_rand(5, 25);
+                    $color = mt_rand(20, 70);
+                    $outEffects[] = "$effect $gain $color";
+                    break;
+
+                case 'pitch':
+                    $cents = mt_rand(-300, 300);
+                    $outEffects[] = "$effect $cents";
+                    break;
+
+                case 'reverb':
+                    $reverberance = mt_rand(20, 80);
+                    $damping      = mt_rand(10, 80);
+                    $scale        = mt_rand(85, 100);
+                    $depth        = mt_rand(90, 100);
+                    $predelay     = mt_rand(0, 5);
+                    $outEffects[] = "$effect $reverberance $damping $scale $depth $predelay";
+                    break;
+
+                case 'tempo':
+                    $factor = mt_rand(65, 135) / 100.0;
+                    $outEffects[] = "$effect -s $factor";
+                    break;
+
+                case 'tremolo':
+                    $hz    = mt_rand(10, 30);
+                    $depth = mt_rand(40, 85);
+                    $outEffects[] = "$effect $hz $depth";
+                    break;
+            }
+        }
+
+        return implode(' ', $outEffects);
+    }
+
+    /**
+     * This function is not yet used.
+     *
+     * Generate random background noise from sweeping oscillators
+     *
+     * @param float $duration  How long in seconds the generated sound will be
+     * @param int $numChannels Number of channels in output wav
+     * @param int $sampleRate  Sample rate of output wav
+     * @param int $bitRate     Bits per sample (8, 16, 24)
+     * @return string          Audio data in wav format
+     */
+    protected function getSoxNoiseData($duration, $numChannels, $sampleRate, $bitRate)
+    {
+        $shapes = array('sine', 'square', 'triangle', 'sawtooth', 'trapezium');
+        $steps  = array(':', '+', '/', '-');
+        $selShapes = array_rand($shapes, 2);
+        $selSteps  = array_rand($steps, 2);
+        $sweep0    = array();
+        $sweep0[0] = mt_rand(100, 700);
+        $sweep0[1] = mt_rand(1500, 2500);
+        $sweep1    = array();
+        $sweep1[0] = mt_rand(500, 1000);
+        $sweep1[1] = mt_rand(1200, 2000);
+
+        if (mt_rand(0, 10) % 2 == 0)
+            $sweep0 = array_reverse($sweep0);
+
+        if (mt_rand(0, 10) % 2 == 0)
+            $sweep1 = array_reverse($sweep1);
+
+        $cmd = sprintf("%s -c %d -r %d -b %d -n -t wav - synth noise create vol 0.3 synth %.2f %s mix %d%s%d vol 0.3 synth %.2f %s fmod %d%s%d vol 0.3",
+                       $this->sox_binary_path,
+                       $numChannels,
+                       $sampleRate,
+                       $bitRate,
+                       $duration,
+                       $shapes[$selShapes[0]],
+                       $sweep0[0],
+                       $steps[$selSteps[0]],
+                       $sweep0[1],
+                       $duration,
+                       $shapes[$selShapes[1]],
+                       $sweep1[0],
+                       $steps[$selSteps[1]],
+                       $sweep1[1]
+                       );
+        $data = `$cmd`;
+
+        return $data;
+    }
+
+    /**
+     * Convert WAV data to MP3 using the Lame MP3 encoder binary
+     *
+     * @param string $data  Contents of the WAV file to convert
+     * @return string       MP3 file data
+     */
+    protected function wavToMp3($data)
+    {
+        if (!file_exists(self::$lame_binary_path) || !is_executable(self::$lame_binary_path)) {
+            throw new Exception('Lame binary "' . $this->lame_binary_path . '" does not exist or is not executable');
+        }
+
+        // size of wav data input
+        $size = strlen($data);
+
+        // file descriptors for reading and writing to the Lame process
+        $descriptors = array(
+                0 => array('pipe', 'r'), // stdin
+                1 => array('pipe', 'w'), // stdout
+                2 => array('pipe', 'a'), // stderr
+        );
+
+        if (strtoupper(substr(PHP_OS, 0, 3)) === 'WIN') {
+            // workaround for Windows conversion
+            // writing to STDIN seems to hang indefinitely after writing approximately 0xC400 bytes
+            $wavinput = tempnam(sys_get_temp_dir(), 'wav');
+            if (!$wavinput) {
+                throw new Exception('Failed to create temporary file for WAV to MP3 conversion');
+            }
+            file_put_contents($wavinput, $data);
+            $size = 0;
+        } else {
+            $wavinput = '-'; // stdin
+        }
+
+        // Mono, variable bit rate, 32 kHz sampling rate, read WAV from stdin, write MP3 to stdout
+        $cmd  = sprintf("%s -m m -v -b 32 %s -", self::$lame_binary_path, $wavinput);
+        $proc = proc_open($cmd, $descriptors, $pipes);
+
+        if (!is_resource($proc)) {
+            throw new Exception('Failed to open process for MP3 encoding');
+        }
+
+        stream_set_blocking($pipes[0], 0); // set stdin to be non-blocking
+
+        for ($written = 0; $written < $size; $written += $len) {
+            // write to stdin until all WAV data is written
+            $len = fwrite($pipes[0], substr($data, $written, 0x20000));
+
+            if ($len === 0) {
+                // fwrite wrote no data, make sure process is still alive, otherwise wait for it to process
+                $status = proc_get_status($proc);
+                if ($status['running'] === false) break;
+                usleep(25000);
+            } else if ($written < $size) {
+                // couldn't write all data, small pause and try again
+                usleep(10000);
+            } else if ($len === false) {
+                // fwrite failed, should not happen
+                break;
+            }
+        }
+
+        fclose($pipes[0]);
+
+        $data = stream_get_contents($pipes[1]);
+        $err  = trim(stream_get_contents($pipes[2]));
+
+        fclose($pipes[1]);
+        fclose($pipes[2]);
+
+        $return = proc_close($proc);
+
+        if ($wavinput != '-') unlink($wavinput); // delete temp file on Windows
+
+        if ($return !== 0) {
+            throw new Exception("Failed to convert WAV to MP3.  Shell returned ({$return}): {$err}");
+        } else if ($written < $size) {
+            throw new Exception('Failed to convert WAV to MP3.  Failed to write all data to encoder');
+        }
+
+        return $data;
+    }
+
+    /**
+     * 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 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);
+    }
+}
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