securimage.php

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<?php
 
/**
 * Project:     Securimage: A PHP class for creating and managing form CAPTCHA images<br />
 * File:        securimage.php<br />
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or any later version.<br /><br />
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.<br /><br />
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA<br /><br />
 *
 * Any modifications to the library should be indicated clearly in the source code
 * to inform users that the changes are not a part of the original software.<br /><br />
 *
 * If you found this script useful, please take a quick moment to rate it.<br />
 * http://www.hotscripts.com/rate/49400.html  Thanks.
 *
 * @link http://www.phpcaptcha.org Securimage PHP CAPTCHA
 * @link http://www.phpcaptcha.org/latest.zip Download Latest Version
 * @link http://www.phpcaptcha.org/Securimage_Docs/ Online Documentation
 * @copyright 2009 Drew Phillips
 * @author Drew Phillips <drew@drew-phillips.com>
 * @version 2.0.1 BETA (December 6th, 2009)
 * @package Securimage
 *
 */
 
/**
 ChangeLog
 
 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
 
 */
 
/**
 * Output images in JPEG format
 */
if (!defined('SI_IMAGE_JPEG'))
  define('SI_IMAGE_JPEG', 1);
/**
 * Output images in PNG format
 */
if (!defined('SI_IMAGE_PNG'))
  define('SI_IMAGE_PNG',  2);
/**
 * Output images in GIF format (not recommended)
 * Must have GD >= 2.0.28!
 */
if (!defined('SI_IMAGE_GIF'))
  define('SI_IMAGE_GIF',  3);
 
/**
 * Securimage CAPTCHA Class.
 *
 * @package    Securimage
 * @subpackage classes
 *
 */
class Securimage {
 
        /**
         * The desired width of the CAPTCHA image.
         *
         * @var int
         */
        var $image_width;
 
        /**
         * The desired width of the CAPTCHA image.
         *
         * @var int
         */
        var $image_height;
 
        /**
         * The image format for output.<br />
         * Valid options: SI_IMAGE_PNG, SI_IMAGE_JPG, SI_IMAGE_GIF
         *
         * @var int
         */
        var $image_type;
 
        /**
         * The length of the code to generate.
         *
         * @var int
         */
        var $code_length;
 
        /**
         * The character set for individual characters in the image.<br />
         * Letters are converted to uppercase.<br />
         * The font must support the letters or there may be problematic substitutions.
         *
         * @var string
         */
        var $charset;
 
        /**
         * Create codes using this word list
         *
         * @var string  The path to the word list to use for creating CAPTCHA codes
         */
        var $wordlist_file;
 
        /**
         * Use wordlist of not
         *
         * @var bool true to use wordlist file, false to use random code
         */
        var $use_wordlist = false;
 
        /**
         * Note: Use of GD fonts is not recommended as many distortion features are not available<br />
         * The GD font to use.<br />
         * Internal gd fonts can be loaded by their number.<br />
         * Alternatively, a file path can be given and the font will be loaded from file.
         *
         * @var mixed
         */
        var $gd_font_file;
 
        /**
         * The approximate size of the font in pixels.<br />
         * This does not control the size of the font because that is determined by the GD font itself.<br />
         * This is used to aid the calculations of positioning used by this class.<br />
         *
         * @var int
         */
        var $gd_font_size;
 
        /**
         * Use a gd font instead of TTF
         *
         * @var bool true for gd font, false for TTF
         */
        var $use_gd_font;
 
        // Note: These font options below do not apply if you set $use_gd_font to true with the exception of $text_color
 
        /**
         * The path to the TTF font file to load.
         *
         * @var string
         */
        var $ttf_file;
 
        /**
         * How much to distort image, higher = more distortion.<br />
         * Distortion is only available when using TTF fonts.<br />
         *
         * @var float
         */
        var $perturbation;
 
        /**
         * The minimum angle in degrees, with 0 degrees being left-to-right reading text.<br />
         * Higher values represent a counter-clockwise rotation.<br />
         * For example, a value of 90 would result in bottom-to-top reading text.<br />
         * This value along with maximum angle distance do not need to be very high with perturbation
         *
         * @var int
         */
        var $text_angle_minimum;
 
        /**
         * The minimum angle in degrees, with 0 degrees being left-to-right reading text.<br />
         * Higher values represent a counter-clockwise rotation.<br />
         * For example, a value of 90 would result in bottom-to-top reading text.
         *
         * @var int
         */
        var $text_angle_maximum;
 
        /**
         * The X-Position on the image where letter drawing will begin.<br />
         * This value is in pixels from the left side of the image.
         *
         * @var int
         * @deprecated 2.0
         */
        var $text_x_start;
 
        /**
         * The background color for the image as a Securimage_Color.<br />
         *
         * @var Securimage_Color
         */
        var $image_bg_color;
 
        /**
         * Scan this directory for gif, jpg, and png files to use as background images.<br />
         * A random image file will be picked each time.<br />
         * Change from null to the full path to your directory.<br />
         * i.e. var $background_directory = $_SERVER['DOCUMENT_ROOT'] . '/securimage/backgrounds';
         * Make sure not to pass a background image to the show function, otherwise this directive is ignored.
         *
         * @var string
         */
        var $background_directory = null; //'./backgrounds';
 
        /**
         * The text color to use for drawing characters as a Securimage_Color.<br />
         * This value is ignored if $use_multi_text is set to true.<br />
         * Make sure this contrasts well with the background color or image.<br />
         *
         * @see Securimage::$use_multi_text
         * @var Securimage_Color
         */
        var $text_color;
 
        /**
         * Set to true to use multiple colors for each character.
         *
         * @see Securimage::$multi_text_color
         * @var boolean
         */
        var $use_multi_text;
 
        /**
         * Array of Securimage_Colors which will be randomly selected for each letter.<br />
         *
         * @var array
         */
        var $multi_text_color;
 
        /**
         * Set to true to make the characters appear transparent.
         *
         * @see Securimage::$text_transparency_percentage
         * @var boolean
         */
        var $use_transparent_text;
 
        /**
         * The percentage of transparency, 0 to 100.<br />
         * A value of 0 is completely opaque, 100 is completely transparent (invisble)
         *
         * @see Securimage::$use_transparent_text
         * @var int
         */
        var $text_transparency_percentage;
 
 
        // Line options
        /**
        * Draw vertical and horizontal lines on the image.
        *
        * @see Securimage::$line_color
        * @see Securimage::$draw_lines_over_text
        * @var boolean
        */
        var $num_lines;
 
        /**
         * Color of lines drawn over text
         *
         * @var string
         */
        var $line_color;
 
        /**
         * Draw the lines over the text.<br />
         * If fales lines will be drawn before putting the text on the image.
         *
         * @var boolean
         */
        var $draw_lines_over_text;
 
        /**
         * Text to write at the bottom corner of captcha image
         * 
         * @since 2.0
         * @var string Signature text
         */
        var $image_signature;
        
        /**
         * Color to use for writing signature text
         * 
         * @since 2.0
         * @var Securimage_Color
         */
        var $signature_color;
 
        var $signature_font;
        /**
         * Full path to the WAV files to use to make the audio files, include trailing /.<br />
         * Name Files  [A-Z0-9].wav
         *
         * @since 1.0.1
         * @var string
         */
        var $audio_path;
 
        /**
         * Type of audio file to generate (mp3 or wav)
         *
         * @var string
         */
        var $audio_format;
 
        /**
         * The session name to use if not the default.  Blank for none
         *
         * @see http://php.net/session_name
         * @since 2.0
         * @var string
         */
        var $session_name = '';
        
        /**
         * The amount of time in seconds that a code remains valid.<br />
         * Any code older than this number will be considered invalid even if entered correctly.<br />
         * Any non-numeric or value less than 1 disables this functionality.
         * 
         * @var int
         */
        var $expiry_time;
        
        /**
         * Path to the file to use for storing codes for users.<br />
         * THIS FILE MUST ABSOLUTELY NOT BE ACCESSIBLE FROM A WEB BROWSER!!<br />
         * Put this file in a directory below the web root or one that is restricted (i.e. an apache .htaccess file with deny from all)<br />
         * If you cannot meet those requirements your forms may not be completely protected.<br />
         * You could obscure the database file name but this is also not recommended.
         * 
         * @var string
         */
        var $sqlite_database;
        
        /**
         * Use an SQLite database for storing codes as a backup to sessions.<br />
         * Note: Sessions will still be used 
         */
        var $use_sqlite_db;
 
 
        //END USER CONFIGURATION
        //There should be no need to edit below unless you really know what you are doing.
 
        /**
         * The gd image resource.
         *
         * @access private
         * @var resource
         */
        var $im;
 
        /**
         * Temporary image for rendering
         *
         * @access private
         * @var resource
         */
        var $tmpimg;
 
        /**
         * Internal scale factor for anti-alias @hkcaptcha
         *
         * @access private
         * @since 2.0
         * @var int
         */
        var $iscale; // internal scale factor for anti-alias @hkcaptcha
 
        /**
         * The background image resource
         *
         * @access private
         * @var resource
         */
        var $bgimg;
 
        /**
         * The code generated by the script
         *
         * @access private
         * @var string
         */
        var $code;
 
        /**
         * The code that was entered by the user
         *
         * @access private
         * @var string
         */
        var $code_entered;
 
        /**
         * Whether or not the correct code was entered
         *
         * @access private
         * @var boolean
         */
        var $correct_code;
        
        /**
         * Handle to SQLite database
         *
         * @access private
         * @var resource
         */
        var $sqlite_handle;
        
        /**
         * Color resource for image line color
         * 
         * @access private
         * @var int
         */
        var $gdlinecolor;
        
        /**
         * Array of colors for multi colored codes
         * 
         * @access private
         * @var array
         */
        var $gdmulticolor;
        
        /**
         * Color resource for image font color
         * 
         * @access private
         * @var int
         */
        var $gdtextcolor;
        
        /**
         * Color resource for image signature color
         * 
         * @access private
         * @var int
         */
        var $gdsignaturecolor;
        
        /**
         * Color resource for image background color
         * 
         * @access private
         * @var int
         */
        var $gdbgcolor;
        
 
        /**
         * Class constructor.<br />
         * Because the class uses sessions, this will attempt to start a session if there is no previous one.<br />
         * If you do not start a session before calling the class, the constructor must be called before any
         * output is sent to the browser.
         *
         * <code>
         *   $securimage = new Securimage();
         * </code>
         *
         */
        function __construct()
        {
                // Initialize session or attach to existing
                if ( session_id() == '' ) { // no session has been started yet, which is needed for validation
                        if (trim($this->session_name) != '') {
                                session_name($this->session_name); // set session name if provided
                        }
                        session_start();
                }
 
                // Set Default Values
                $this->image_width   = 230;
                $this->image_height  = 80;
                $this->image_type    = SI_IMAGE_PNG;
 
                $this->code_length   = 6;
                $this->charset       = 'ABCDEFGHKLMNPRSTUVWYZabcdefghklmnprstuvwyz23456789';
                $this->wordlist_file = './words/words.txt';
                $this->use_wordlist  = false;
 
                $this->gd_font_file  = 'gdfonts/automatic.gdf';
                $this->use_gd_font   = false;
                $this->gd_font_size  = 24;
                $this->text_x_start  = 15;
 
                $this->ttf_file      = './AHGBold.ttf';
 
                $this->perturbation       = 0.75;
                $this->iscale             = 5;
                $this->text_angle_minimum = 0;
                $this->text_angle_maximum = 0;
 
                $this->image_bg_color   = new Securimage_Color(0xff, 0xff, 0xff);
    $this->text_color       = new Securimage_Color(0x3d, 0x3d, 0x3d);
                $this->multi_text_color = array(new Securimage_Color(0x0, 0x20, 0xCC),
                                                new Securimage_Color(0x0, 0x30, 0xEE),
                                                new Securimage_color(0x0, 0x40, 0xCC),
                                                new Securimage_Color(0x0, 0x50, 0xEE),
                                                new Securimage_Color(0x0, 0x60, 0xCC));
                $this->use_multi_text   = false;
 
                $this->use_transparent_text         = false;
                $this->text_transparency_percentage = 30;
 
                $this->num_lines            = 10;
                $this->line_color           = new Securimage_Color(0x3d, 0x3d, 0x3d);
                $this->draw_lines_over_text = true;
 
                $this->image_signature = '';
                $this->signature_color = new Securimage_Color(0x20, 0x50, 0xCC);
                $this->signature_font  = './AHGBold.ttf';
 
                $this->audio_path   = './audio/';
                $this->audio_format = 'mp3';
                $this->session_name = '';
                $this->expiry_time  = 900;
                
                $this->sqlite_database = 'database/securimage.sqlite';
                $this->use_sqlite_db   = false;
                
                $this->sqlite_handle = false;
        }
 
        /**
         * Generate a code and output the image to the browser.
         *
         * <code>
         *   <?php
         *   include 'securimage.php';
         *   $securimage = new Securimage();
         *   $securimage->show('bg.jpg');
         *   ?>
         * </code>
         *
         * @param string $background_image  The path to an image to use as the background for the CAPTCHA
         */
        function show($background_image = "")
        {
                if($background_image != "" && is_readable($background_image)) {
                        $this->bgimg = $background_image;
                }
 
                $this->doImage();
        }
 
        /**
         * Validate the code entered by the user.
         *
         * <code>
         *   $code = $_POST['code'];
         *   if ($securimage->check($code) == false) {
         *     die("Sorry, the code entered did not match.");
         *   } else {
         *     $valid = true;
         *   }
         * </code>
         * @param string $code  The code the user entered
         * @return boolean  true if the code was correct, false if not
         */
        function check($code)
        {
                $this->code_entered = $code;
                $this->validate();
                return $this->correct_code;
        }
 
        /**
         * Output audio file with HTTP headers to browser
         * 
         * <code>
         *   $sound = new Securimage();
         *   $sound->audio_format = 'mp3';
         *   $sound->outputAudioFile();
         * </code>
         * 
         * @since 2.0
         */
        function outputAudioFile()
        {
                if (strtolower($this->audio_format) == 'wav') {
                        header('Content-type: audio/x-wav');
                        $ext = 'wav';
                } else {
                        header('Content-type: audio/mpeg'); // default to mp3
                        $ext = 'mp3';
                }
 
                header("Content-Disposition: attachment; filename=\"securimage_audio.{$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');
 
                $audio = $this->getAudibleCode($ext);
 
                header('Content-Length: ' . strlen($audio));
 
                echo $audio;
                exit;
        }
 
        /**
         * Generate and output the image
         *
         * @access private
         *
         */
        function doImage()
        {
                if ($this->use_gd_font == true || $this->iscale == null || $this->iscale == 0) {
                        $this->iscale = 1;
                }
                if($this->use_transparent_text == true || $this->bgimg != "") {
                        $this->im     = imagecreatetruecolor($this->image_width, $this->image_height);
                        $this->tmpimg = imagecreatetruecolor($this->image_width * $this->iscale, $this->image_height * $this->iscale);
 
                } else { //no transparency
                        $this->im     = imagecreate($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();
 
                $this->createCode();
 
                if (!$this->draw_lines_over_text && $this->num_lines > 0) $this->drawLines();
 
                $this->drawWord();
                if ($this->use_gd_font == false && is_readable($this->ttf_file)) $this->distortedCopy();
 
                if ($this->draw_lines_over_text && $this->num_lines > 0) $this->drawLines();
 
                if (trim($this->image_signature) != '')  $this->addSignature();
 
                $this->output();
 
        }
        
        /**
         * Allocate all colors that will be used in the CAPTCHA image
         * 
         * @since 2.0.1
         * @access private
         */
        function allocateColors()
        {
                // allocate bg color first for imagecreate
                $this->gdbgcolor = imagecolorallocate($this->im, $this->image_bg_color->r??0, $this->image_bg_color->g??0, $this->image_bg_color->b??0);
 
        $this->text_color->r=$this->text_color->r??rand(0,255);
        $this->text_color->g=$this->text_color->g??rand(0,255);
        $this->text_color->b=$this->text_color->b??rand(0,255);
        $this->line_color->r=$this->line_color->r??rand(0,255);
        $this->line_color->g=$this->line_color->g??rand(0,255);
        $this->line_color->b=$this->line_color->b??rand(0,255);
 
 
 
                $alpha = intval($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);
                } elseif ( $this->text_color != null ) {
                        $this->gdtextcolor = imagecolorallocate($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);
                } else {
            $red=rand(0,255);
            $green=rand(0,255);
            $blue=rand(0,255);
            $this->gdtextcolor = imagecolorallocate($this->im, $red, $green,$blue);
            $this->gdlinecolor = imagecolorallocate($this->im, $red, $green, $blue);
        }
    
    $this->gdsignaturecolor = imagecolorallocate($this->im, $this->signature_color->r??0, $this->signature_color->g??0, $this->signature_color->b??0);
    
    if ($this->use_multi_text == true) {
        $this->gdmulticolor = array();
        
        foreach($this->multi_text_color??[] as $color) {
            $color->r=$color->r??rand(0,255);
            $color->g= $color->g??rand(0,255);
            $color->b=$color->b??rand(0,255);
                if ($this->use_transparent_text == true) {
                  $this->gdmulticolor[] = imagecolorallocatealpha($this->im, $color->r, $color->g, $color->b, $alpha);
                } else {
                        $this->gdmulticolor[] = imagecolorallocate($this->im, $color->r, $color->g, $color->b);
                }
        }
    }
        }
 
        /**
         * Set the background of the CAPTCHA image
         *
         * @access private
         *
         */
        function setBackground()
        {
                imagefilledrectangle($this->im, 0, 0, $this->image_width * $this->iscale, $this->image_height * $this->iscale, $this->gdbgcolor);
    imagefilledrectangle($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;
                                }
                        }
                }
 
                $dat = @getimagesize($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;
                        case 15: $newim = @imagecreatefromwbmp($this->bgimg); break;
                        case 16: $newim = @imagecreatefromxbm($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));
        }
 
        /**
         * Return the full path to a random gif, jpg, or png from the background directory.
         *
         * @access private
         * @see Securimage::$background_directory
         * @return mixed  false if none found, string $path if found
         */
        function getBackgroundFromDirectory()
        {
                $images = array();
 
                if ($dh = opendir($this->background_directory)) {
                        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, '/') . '/' . $images[rand(0, sizeof($images)-1)];
                        }
                }
 
                return false;
        }
 
        /**
         * Draw random curvy lines over the image<br />
         * Modified code from HKCaptcha
         *
         * @since 2.0
         * @access private
         *
         */
        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;
                        $y = rand($this->image_height * 0.1, $this->image_height * 0.9);
                         
                        $theta = ($this->frand()-0.5) * M_PI * 0.7;
                        $w = $this->image_width;
                        $len = rand($w * 0.4, $w * 0.7);
                        $lwid = 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);
                                $x=(int) $x;
                                $y=(int) $y;
                                imagefilledrectangle($this->im, $x, $y, $x + $lwid, $y + $lwid, $this->gdlinecolor);
                        }
                }
        }
 
        /**
         * Draw the CAPTCHA code over the image
         *
         * @access private
         *
         */
        function drawWord()
        {
                $width2 = $this->image_width * $this->iscale;
                $height2 = $this->image_height * $this->iscale;
                 
                if ($this->use_gd_font == true || !is_readable($this->ttf_file??"")) {
                        if (!is_int($this->gd_font_file)) { //is a file name
                                $font = @imageloadfont($this->gd_font_file??"");
                                if ($font == false) {
                                        trigger_error("Failed to load GD Font file {$this->gd_font_file} ", E_USER_WARNING);
                                        return;
                                }
                        } else { //gd font identifier
                                $font = $this->gd_font_file;
                        }
 
                        imagestring($this->im, $font, $this->text_x_start, ($this->image_height / 2) - ($this->gd_font_size / 2), $this->code, $this->gdtextcolor);
                } else { //ttf font
                        $font_size = $height2 * .35;
                        $bb = imagettfbbox($font_size, 0, $this->ttf_file, $this->code);
                        $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]);
 
                        $strlen = strlen($this->code);
                        if (!is_array($this->multi_text_color)) $this->use_multi_text = false;
 
 
                        if ($this->use_multi_text == false && $this->text_angle_minimum == 0 && $this->text_angle_maximum == 0) { // no angled or multi-color characters
                                imagettftext($this->tmpimg, $font_size, 0, $x, $y, $this->gdtextcolor, $this->ttf_file, $this->code);
                        } else {
                                for($i = 0; $i < $strlen; ++$i) {
                                        $angle = rand($this->text_angle_minimum, $this->text_angle_maximum);
                                        $y = rand($y - 5, $y + 5);
                                        if ($this->use_multi_text == true) {
                                                $font_color = $this->gdmulticolor[rand(0, sizeof($this->gdmulticolor) - 1)];
                                        } else {
                                                $font_color = $this->gdtextcolor;
                                        }
                                        
                                        $ch = $this->code[$i];
                                         
                                        imagettftext($this->tmpimg, $font_size, $angle, $x, $y, $font_color, $this->ttf_file, $ch);
                                         
                                        // estimate character widths to increment $x without creating spaces that are too large or too small
                                        // these are best estimates to align text but may vary between fonts
                                        // for optimal character widths, do not use multiple text colors or character angles and the complete string will be written by imagettftext
                                        if (strpos('abcdeghknopqsuvxyz', $ch) !== false) {
                                                $min_x = $font_size - ($this->iscale * 6);
                                                $max_x = $font_size - ($this->iscale * 6);
                                        } else if (strpos('ilI1', $ch) !== false) {
                                                $min_x = $font_size / 5;
                                                $max_x = $font_size / 3;
                                        } else if (strpos('fjrt', $ch) !== false) {
                                                $min_x = $font_size - ($this->iscale * 12);
                                                $max_x = $font_size - ($this->iscale * 12);
                                        } else if ($ch == 'wm') {
                                                $min_x = $font_size;
                                                $max_x = $font_size + ($this->iscale * 3);
                                        } else { // numbers, capitals or unicode
                                                $min_x = $font_size + ($this->iscale * 2);
                                                $max_x = $font_size + ($this->iscale * 5);
                                        }
                                         
                                        $x += rand((int)$min_x,(int) $max_x);
                                } //for loop
                        } // angled or multi-color
                } //else ttf font
                //$this->im = $this->tmpimg;
                //$this->output();
        } //function
 
        /**
         * Warp text from temporary image onto final image.<br />
         * Modified for securimage
         *
         * @access private
         * @since 2.0
         * @author Han-Kwang Nienhuys modified
         * @copyright Han-Kwang Neinhuys
         *
         */
        function distortedCopy()
        {
                $numpoles = 3; // distortion factor
                 
                // make array of poles AKA attractor points
                for ($i = 0; $i < $numpoles; ++$i) {
                        $px[$i]  = rand((int) ($this->image_width * 0.3), (int)( $this->image_width * 0.7));
                        $py[$i]  = rand((int) ($this->image_height * 0.3),(int) ($this->image_height * 0.7));
                        $rad[$i] = rand((int) ($this->image_width * 0.4), (int) ($this->image_width * 0.7));
                        $tmp     = -$this->frand() * 0.15 - 0.15;
                        $amp[$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, (int) $x,(int) $y);
                                }
 
                                if ($c != $bgCol) { // only copy pixels of letters to preserve any background image
                                        imagesetpixel($this->im, $ix, $iy, $c);
                                }
                        }
                }
        }
 
        /**
         * Create a code and save to the session
         *
         * @access private
         * @since 1.0.1
         *
         */
        function createCode()
        {
                $this->code = false;
 
                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->saveData();
        }
 
        /**
         * Generate a code
         *
         * @access private
         * @param int $len  The code length
         * @return string
         */
        function generateCode($len)
        {
                $code = '';
 
                for($i = 1, $cslen = strlen($this->charset??""); $i <= $len; ++$i) {
                        $code .= $this->charset[rand(0, $cslen - 1)];
                }
                return $code;
        }
 
        /**
         * Reads a word list file to get a code
         *
         * @access private
         * @since 1.0.2
         * @return mixed  false on failure, a word on success
         */
        function readCodeFromFile()
        {
                $fp = @fopen($this->wordlist_file, 'rb');
                if (!$fp) return false;
 
                $fsize = filesize($this->wordlist_file);
                if ($fsize < 32) return false; // too small of a list to be effective
 
                if ($fsize < 128) {
                        $max = $fsize; // still pretty small but changes the range of seeking
                } else {
                        $max = 128;
                }
 
                fseek($fp, rand(0, $fsize - $max), SEEK_SET);
                $data = fread($fp, 128); // read a random 128 bytes from file
                fclose($fp);
                $data = preg_replace("/\r?\n/", "\n", $data);
 
                $start = strpos($data, "\n", rand(0, 100)) + 1; // random start position
                $end   = strpos($data, "\n", $start);           // find end of word
 
                return strtolower(substr($data, $start, $end - $start)); // return substring in 128 bytes
        }
 
        /**
         * Output image to the browser
         *
         * @access private
         *
         */
        function output()
        {
                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($this->image_type)
                {
                        case SI_IMAGE_JPEG:
                                header("Content-Type: image/jpeg");
                                imagejpeg($this->im, null, 90);
                                break;
 
                        case SI_IMAGE_GIF:
                                header("Content-Type: image/gif");
                                imagegif($this->im);
                                break;
 
                        default:
                                header("Content-Type: image/png");
                                imagepng($this->im);
                                break;
                }
 
                imagedestroy($this->im);
                exit;
        }
 
        /**
         * Get WAV or MP3 file data of the spoken code.<br />
         * This is appropriate for output to the browser as audio/x-wav or audio/mpeg
         *
         * @since 1.0.1
         * @return string  WAV or MP3 data
         *
         */
        function getAudibleCode($format = 'wav')
        {
                $letters = array();
                $code    = $this->getCode();
 
                if ($code == '') {
                        $this->createCode();
                        $code = $this->getCode();
                }
 
                for($i = 0; $i < strlen($code); ++$i) {
                        $letters[] = $code[$i];
                }
 
                if ($format == 'mp3') {
                        return $this->generateMP3($letters);
                } else {
                        return $this->generateWAV($letters);
                }
        }
 
        /**
         * Set the path to the audio directory.<br />
         *
         * @since 1.0.4
         * @return bool true if the directory exists and is readble, false if not
         */
        function setAudioPath($audio_directory)
        {
                if (is_dir($audio_directory) && is_readable($audio_directory)) {
                        $this->audio_path = $audio_directory;
                        return true;
                } else {
                        return false;
                }
        }
 
        /**
         * Save the code in the session
         *
         * @access private
         *
         */
        function saveData()
        {
                $_SESSION['securimage_code_value'] = strtolower($this->code);
                $_SESSION['securimage_code_ctime'] = time();
                
                $this->saveCodeToDatabase();
        }
 
        /**
         * Validate the code to the user code
         *
         * @access private
         *
         */
        function validate()
        {
            $code='';
                // retrieve code from session, if no code exists check sqlite database if supported.
                
                if (isset($_SESSION['securimage_code_value']) && trim($_SESSION['securimage_code_value']) != '') {
                        if ($this->isCodeExpired($_SESSION['securimage_code_ctime']) == false) { 
                          $code = $_SESSION['securimage_code_value'];
                        }
                } else if ($this->use_sqlite_db == true && function_exists('sqlite_open')) { // no code in session - may mean user has cookies turned off
                        $this->openDatabase();
                        $code = $this->getCodeFromDatabase();
                } else {
                        // session code invalid or non-existant and code not found in sqlite db or sqlite is not available
                        $code = '';
                }
                
                $code               = trim(strtolower($code));
                $code_entered       = trim(strtolower($this->code_entered));
                $this->correct_code = false;
                
                if ($code != '') {
                        if ($code == $code_entered) {
                          $this->correct_code = true;
                          $_SESSION['securimage_code_value'] = '';
                          $_SESSION['securimage_code_ctime'] = '';
                          $this->clearCodeFromDatabase();
                  }
                }
        }
 
        /**
         * Get the captcha code
         *
         * @since 1.0.1
         * @return string
         */
        function getCode()
        {
                if (isset($_SESSION['securimage_code_value']) && !empty($_SESSION['securimage_code_value'])) {
                        return strtolower($_SESSION['securimage_code_value']);
                } else {
                        if ($this->sqlite_handle == false) $this->openDatabase();
                        
                        return $this->getCodeFromDatabase(); // attempt to get from database, returns empty string if sqlite is not available or disabled
                }
        }
 
        /**
         * Check if the user entered code was correct
         *
         * @access private
         * @return boolean
         */
        function checkCode()
        {
                return $this->correct_code;
        }
 
        /**
         * Generate a wav file by concatenating individual files
         *
         * @since 1.0.1
         * @access private
         * @param array $letters  Array of letters to build a file from
         * @return string  WAV file data
         */
        function generateWAV($letters)
        {
                $data_len    = 0;
                $files       = array();
                $out_data    = '';
 
                foreach ($letters as $letter) {
                        $filename = $this->audio_path . strtoupper($letter) . '.wav';
 
                        $fp = fopen($filename, 'rb');
 
                        $file = array();
 
                        $data = fread($fp, filesize($filename)); // read file in
 
                        $header = substr($data, 0, 36);
                        $body   = substr($data, 44);
 
 
                        $data = unpack('NChunkID/VChunkSize/NFormat/NSubChunk1ID/VSubChunk1Size/vAudioFormat/vNumChannels/VSampleRate/VByteRate/vBlockAlign/vBitsPerSample', $header);
 
                        $file['sub_chunk1_id']   = $data['SubChunk1ID'];
                        $file['bits_per_sample'] = $data['BitsPerSample'];
                        $file['channels']        = $data['NumChannels'];
                        $file['format']          = $data['AudioFormat'];
                        $file['sample_rate']     = $data['SampleRate'];
                        $file['size']            = $data['ChunkSize'] + 8;
                        $file['data']            = $body;
 
                        if ( ($p = strpos($file['data'], 'LIST')) !== false) {
                                // If the LIST data is not at the end of the file, this will probably break your sound file
                                $info         = substr($file['data'], $p + 4, 8);
                                $data         = unpack('Vlength/Vjunk', $info);
                                $file['data'] = substr($file['data'], 0, $p);
                                $file['size'] = $file['size'] - (strlen($file['data']) - $p);
                        }
 
                        $files[] = $file;
                        $data    = null;
                        $header  = null;
                        $body    = null;
 
                        $data_len += strlen($file['data']);
 
                        fclose($fp);
                }
 
                $out_data = '';
                for($i = 0; $i < sizeof($files); ++$i) {
                        if ($i == 0) { // output header
                                $out_data .= pack('C4VC8', ord('R'), ord('I'), ord('F'), ord('F'), $data_len + 36, ord('W'), ord('A'), ord('V'), ord('E'), ord('f'), ord('m'), ord('t'), ord(' '));
 
                                $out_data .= pack('VvvVVvv',
                                16,
                                $files[$i]['format'],
                                $files[$i]['channels'],
                                $files[$i]['sample_rate'],
                                $files[$i]['sample_rate'] * (($files[$i]['bits_per_sample'] * $files[$i]['channels']) / 8),
                                ($files[$i]['bits_per_sample'] * $files[$i]['channels']) / 8,
                                $files[$i]['bits_per_sample'] );
 
                                $out_data .= pack('C4', ord('d'), ord('a'), ord('t'), ord('a'));
 
                                $out_data .= pack('V', $data_len);
                        }
 
                        $out_data .= $files[$i]['data'];
                }
 
                $this->scrambleAudioData($out_data, 'wav');
                return $out_data;
        }
 
        /**
         * Randomly modify the audio data to scramble sound and prevent binary recognition.<br />
         * Take care not to "break" the audio file by leaving the header data intact.
         *
         * @since 2.0
         * @access private
         * @param $data Sound data in mp3 of wav format
         */
        function scrambleAudioData(&$data, $format)
        {
                if ($format == 'wav') {
                        $start = strpos($data, 'data') + 4; // look for "data" indicator
                        if ($start === false) $start = 44;  // if not found assume 44 byte header
                } else { // mp3
                        $start = 4; // 4 byte (32 bit) frame header
                }
                 
                $start  += rand(1, 64); // randomize starting offset
                $datalen = strlen($data) - $start - 256; // leave last 256 bytes unchanged
                 
                for ($i = $start; $i < $datalen; $i += 64) {
                        $ch = ord($data[$i]);
                        if ($ch < 9 || $ch > 119) continue;
 
                        $data[$i] = chr($ch + rand(-8, 8));
                }
        }
 
        /**
         * Generate an mp3 file by concatenating individual files
         * @since 1.0.4
         * @access private
         * @param array $letters  Array of letters to build a file from
         * @return string  MP3 file data
         */
        function generateMP3($letters)
        {
                $data_len    = 0;
                $files       = array();
                $out_data    = '';
 
                foreach ($letters as $letter) {
                        $filename = $this->audio_path . strtoupper($letter) . '.mp3';
 
                        $fp   = fopen($filename, 'rb');
                        $data = fread($fp, filesize($filename)); // read file in
 
                        $this->scrambleAudioData($data, 'mp3');
                        $out_data .= $data;
 
                        fclose($fp);
                }
 
 
                return $out_data;
        }
 
        /**
         * Generate random number less than 1
         * @since 2.0
         * @access private
         * @return float
         */
        function frand()
        {
                return 0.0001*rand(0,9999);
        }
 
        /**
         * Print signature text on image
         *
         * @since 2.0
         * @access private
         *
         */
        function addSignature()
        {
                if ($this->use_gd_font) {
                        imagestring($this->im, 5, $this->image_width - (strlen($this->image_signature) * 10), $this->image_height - 20, $this->image_signature, $this->gdsignaturecolor);
                } else {
                         
                        $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);
                }
        }
        
        /**
         * Get hashed IP address of remote user
         * 
         * @access private
         * @since 2.0.1
         * @return string
         */
        function getIPHash()
        {
                return strtolower(md5($_SERVER['REMOTE_ADDR']));
        }
        
        /**
         * Open SQLite database
         * 
         * @access private
         * @since 2.0.1
         * @return bool true if database was opened successfully
         */
        function openDatabase()
        {
                $this->sqlite_handle = false;
                
                if ($this->use_sqlite_db && function_exists('sqlite_open')) {
                        $this->sqlite_handle = sqlite_open($this->sqlite_database, 0666, $error);
                        
                        if ($this->sqlite_handle !== false) {
                                $res = sqlite_query($this->sqlite_handle, "PRAGMA table_info(codes)");
                                if (sqlite_num_rows($res) == 0) {
                                  sqlite_query($this->sqlite_handle, "CREATE TABLE codes (iphash VARCHAR(32) PRIMARY KEY, code VARCHAR(32) NOT NULL, created INTEGER)");
                                }
                        }
                        
                        return $this->sqlite_handle != false;
                }
                
                return $this->sqlite_handle;
        }
        
        /**
         * Save captcha code to sqlite database
         * 
         * @access private
         * @since 2.0.1
         * @return bool true if code was saved, false if not
         */
        function saveCodeToDatabase()
        {
                $success = false;
                
                $this->openDatabase();
                
                if ($this->use_sqlite_db && $this->sqlite_handle !== false) {
                        $ip = $this->getIPHash();
                        $time = time();
                        $code = $_SESSION['securimage_code_value']; // hash code for security - if cookies are disabled the session still exists at this point
                        $success = sqlite_query($this->sqlite_handle, "INSERT OR REPLACE INTO codes(iphash, code, created) VALUES('$ip', '$code', $time)");
                }
                
                return $success !== false;
        }
        
        /**
         * Get stored captcha code from sqlite database based on ip address hash
         * 
         * @access private
         * @since 2.0.1
         * @return string captcha code
         */
        function getCodeFromDatabase()
        {
    $code = '';
 
    if ($this->use_sqlite_db && $this->sqlite_handle !== false) {
        $ip = $this->getIPHash();
        
        $res = sqlite_query($this->sqlite_handle, "SELECT * FROM codes WHERE iphash = '$ip'");
        if ($res && sqlite_num_rows($res) > 0) {
                $res = sqlite_fetch_array($res);
                
                if ($this->isCodeExpired($res['created']) == false) {
                        $code = $res['code'];
                }
        }
    }
    
    return $code;
        }
        
        /**
         * Delete a code from the database by ip address hash
         * 
         * @access private
         * @since 2.0.1
         */
        function clearCodeFromDatabase()
        {
                if ($this->sqlite_handle !== false) {
                        $ip = $this->getIPHash();
                        
                        sqlite_query($this->sqlite_handle, "DELETE FROM codes WHERE iphash = '$ip'");
                }
        }
        
        /**
         * Purge codes over a day old from database
         * 
         * @access private
         * @since 2.0.1
         */
        function purgeOldCodesFromDatabase()
        {
                if ($this->use_sqlite_db && $this->sqlite_handle !== false) {
                        $now   = time();
                        $limit = (!is_numeric($this->expiry_time) || $this->expiry_time < 1) ? 86400 : $this->expiry_time;
                        
                        sqlite_query($this->sqlite_handle, "DELETE FROM codes WHERE $now - created > $limit");
                }
        }
        
        /**
         * Check a code to see if it is expired based on creation time
         * 
         * @access private
         * @since 2.0.1
         * @param $creation_time unix timestamp of code creation time
         * @return bool true if code has expired, false if not
         */
        function isCodeExpired($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;
        }
        
} /* class Securimage */
 
 
/**
 * Color object for Securimage CAPTCHA
 *
 * @since 2.0
 * @package Securimage
 * @subpackage classes
 *
 */
class Securimage_Color {
        /**
         * Red component: 0-255
         *
         * @var int
         */
        var $r;
        /**
         * Green component: 0-255
         *
         * @var int
         */
        var $g;
        /**
         * Blue component: 0-255
         *
         * @var int
         */
        var $b;
 
        /**
         * Create a new Securimage_Color object.<br />
         * Specify the red, green, and blue components using their HTML hex code equivalent.<br />
         * Example: The code for the HTML color #4A203C is:<br />
         * $color = new Securimage_Color(0x4A, 0x20, 0x3C);
         *
         * @param $red Red component 0-255
         * @param $green Green component 0-255
         * @param $blue Blue component 0-255
         */
        function __construct($red, $green = null, $blue = null)
        {
                if ($green == null && $blue == null && preg_match('/^#[a-f0-9]{3,6}$/i', $red)) {
                        $col = substr($red, 1);
                        if (strlen($col) == 3) {
                                $red   = str_repeat(substr($col, 0, 1), 2);
                                $green = str_repeat(substr($col, 1, 1), 2);
                                $blue  = str_repeat(substr($col, 2, 1), 2);
                        } else {
                                $red   = substr($col, 0, 2);
                                $green = substr($col, 2, 2);
                                $blue  = substr($col, 4, 2); 
                        }
                        
                        $red   = hexdec($red);
                        $green = hexdec($green);
                        $blue  = hexdec($blue);
                } else {
                        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;
        }
}