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<?php
/**
 *
 * @package   Barcode Creator
 * @copyright (c) 2011 emberlabs.org
 * @license   http://opensource.org/licenses/mit-license.php The MIT License
 * @link      https://github.com/samt/barcode
 *
 * Minimum Requirement: PHP 5.3.0
 */
 
/**
 * Image_Barcode2_Driver_Ean13 class
 *
 * Renders EAN 13 barcodes
 *
 * PHP versions 5
 *
 * LICENSE: This source file is subject to version 3.0 of the PHP license
 * that is available through the world-wide-web at the following URI:
 * http://www.php.net/license/3_0.txt.  If you did not receive a copy of
 * the PHP License and are unable to obtain it through the web, please
 * send a note to [email protected] so we can mail you a copy immediately.
 *
 * @category  Image
 * @package   Image_Barcode2
 * @author    Didier Fournout <[email protected]>
 * @copyright 2005 The PHP Group
 * @license   http://www.php.net/license/3_0.txt  PHP License 3.0
 * @link      http://pear.php.net/package/Image_Barcode2
 */

namespace emberlabs\Barcode;

/**
 * emberlabs Barcode Creator - Ean13
 *           Generate Ean13 Barcodes
 *
 *
 * @license  http://opensource.org/licenses/mit-license.php The MIT License
 * @link        https://github.com/samt/barcode
 */
class Ean13 extends BarcodeBase
{
    /*
     * Coding map
     * @var array 
     */
    private $_codingmap = array(
        '0' => array(
            'A' => array(0,0,0,1,1,0,1),
            'B' => array(0,1,0,0,1,1,1),
            'C' => array(1,1,1,0,0,1,0)
        ),
        '1' => array(
            'A' => array(0,0,1,1,0,0,1),
            'B' => array(0,1,1,0,0,1,1),
            'C' => array(1,1,0,0,1,1,0)
        ),
        '2' => array(
            'A' => array(0,0,1,0,0,1,1),
            'B' => array(0,0,1,1,0,1,1),
            'C' => array(1,1,0,1,1,0,0)
        ),
        '3' => array(
            'A' => array(0,1,1,1,1,0,1),
            'B' => array(0,1,0,0,0,0,1),
            'C' => array(1,0,0,0,0,1,0)
        ),
        '4' => array(
            'A' => array(0,1,0,0,0,1,1),
            'B' => array(0,0,1,1,1,0,1),
            'C' => array(1,0,1,1,1,0,0)
        ),
        '5' => array(
            'A' => array(0,1,1,0,0,0,1),
            'B' => array(0,1,1,1,0,0,1),
            'C' => array(1,0,0,1,1,1,0)
        ),
        '6' => array(
            'A' => array(0,1,0,1,1,1,1),
            'B' => array(0,0,0,0,1,0,1),
            'C' => array(1,0,1,0,0,0,0)
        ),
        '7' => array(
            'A' => array(0,1,1,1,0,1,1),
            'B' => array(0,0,1,0,0,0,1),
            'C' => array(1,0,0,0,1,0,0)
        ),
        '8' => array(
            'A' => array(0,1,1,0,1,1,1),
            'B' => array(0,0,0,1,0,0,1),
            'C' => array(1,0,0,1,0,0,0)
        ),
        '9' => array(
            'A' => array(0,0,0,1,0,1,1),
            'B' => array(0,0,1,0,1,1,1),
            'C' => array(1,1,1,0,1,0,0)
        )
    );

    /*
     * Coding map left
     * @var array 
     */
    private $_codingmapleft = array(
        '0' => array('A','A','A','A','A','A'),
        '1' => array('A','A','B','A','B','B'),
        '2' => array('A','A','B','B','A','B'),
        '3' => array('A','A','B','B','B','A'),
        '4' => array('A','B','A','A','B','B'),
        '5' => array('A','B','B','A','A','B'),
        '6' => array('A','B','B','B','A','A'),
        '7' => array('A','B','A','B','A','B'),
        '8' => array('A','B','A','B','B','A'),
        '9' => array('A','B','B','A','B','A')
    );

    /*
     * Set the data
     *
     * @param mixed data - (int or string) Data to be encoded
     * @return instance of \emberlabs\Barcode\BarcodeInterface
     */
    public function setData($data)
    {
        $this->data = $data;
    }

    /*
     * Generate EAN13 code out of a provided number
     * Code taken from http://stackoverflow.com/questions/19890144/generate-valid-ean13-in-php (unknown copyright / license claims)
     *
     * @param number is the internal code you want to have EANed. The prefix, zero-padding and checksum are added by the function.
     * @return string with complete EAN13 code
     */
    public function generate($number)
    {
        $number = '200' . str_pad($number, 9, '0');
        $weightflag = true;
        $sum = 0;

        // Weight for a digit in the checksum is 3, 1, 3.. starting from the last digit.
        // loop backwards to make the loop length-agnostic. The same basic functionality
        // will work for codes of different lengths.
        for ($i = strlen($number) - 1; $i >= 0; --$i)
        {
            $sum += (int)$number[$i] * ($weightflag?3:1);
            $weightflag = !$weightflag;
        }
        $number .= (10 - ($sum % 10)) % 10;

        return $number;
    }

    public function validate($barcode)
    {
        // check to see if barcode is 13 digits long
        if (!preg_match("/^[0-9]{13}$/", $barcode)) {
            return false;
        }

        $digits = $barcode;

        // 1. Add the values of the digits in the
        // even-numbered positions: 2, 4, 6, etc.
        $even_sum = $digits[1] + $digits[3] + $digits[5] +
            $digits[7] + $digits[9] + $digits[11];

        // 2. Multiply this result by 3.
        $even_sum_three = $even_sum * 3;

        // 3. Add the values of the digits in the
        // odd-numbered positions: 1, 3, 5, etc.
        $odd_sum = $digits[0] + $digits[2] + $digits[4] +
            $digits[6] + $digits[8] + $digits[10];

        // 4. Sum the results of steps 2 and 3.
        $total_sum = $even_sum_three + $odd_sum;

        // 5. The check character is the smallest number which,
        // when added to the result in step 4, produces a multiple of 10.
        $next_ten = (ceil($total_sum / 10)) * 10;
        $check_digit = $next_ten - $total_sum;

        // if the check digit and the last digit of the
        // barcode are OK return true;
        if ($check_digit == $digits[12]) {
            return true;
        }

        return false;
    }

    /*
     * Draw the image
     *
     * @return void
     */
    public function draw()
    {
        // Bars is in reference to a single, 1-level bar
        $pxPerBar = 2;
        
        // Calculate the barcode width
        $barcodewidth = (strlen($this->data)) * (7 * $pxPerBar) 
            + 3 * $pxPerBar  // left
            + 5 * $pxPerBar  // center
            + 3 * $pxPerBar  // right
            ;

        $this->x = ($this->x == 0) ? $barcodewidth : $this->x;
            
        $this->img = @imagecreate($this->x, $this->y);
        
        if (!$this->img)
        {
            throw new \RuntimeException("Ean13: Image failed to initialize");
        }
        
        $white = imagecolorallocate($this->img, 255, 255, 255);
        $black = imagecolorallocate($this->img, 0, 0, 0);
        
        // Fill image with white color
        imagefill($this->img, 0, 0, $white);

        // get the first digit which is the key for creating the first 6 bars
        $key = substr($this->data, 0, 1);

        // Initiate x position centering the bar
        $xpos = ($this->x - $barcodewidth) / 2;
 
        // Draws the left guard pattern (bar-space-bar)
        // bar
        imagefilledrectangle(
            $this->img,
            $xpos,
            0,
            $xpos + $pxPerBar - 1,
            $this->y, 
            $black
        );

        $xpos += $pxPerBar;

        // space
        $xpos += $pxPerBar;

        // bar
        imagefilledrectangle(
            $this->img,
            $xpos,
            0,
            $xpos + $pxPerBar - 1,
            $this->y,
            $black
        );

        $xpos += $pxPerBar;

        // Draw left $this->data contents
        $set_array = $this->_codingmapleft[$key];

        for ($idx = 1; $idx < 7; ++$idx)
        {
            $value = substr($this->data, $idx, 1);

            foreach ($this->_codingmap[$value][$set_array[$idx - 1]] as $bar)
            {
                if ($bar)
                {
                    imagefilledrectangle(
                        $this->img,
                        $xpos,
                        0,
                        $xpos + $pxPerBar - 1,
                        $this->y,
                        $black
                    );
                }

                $xpos += $pxPerBar;
            }
        }

        // Draws the center pattern (space-bar-space-bar-space)
        // space
        $xpos += $pxPerBar;

        // bar
        imagefilledrectangle(
            $this->img,
            $xpos,
            0,
            $xpos + $pxPerBar - 1,
            $this->y,
            $black
        );

        $xpos += $pxPerBar;

        // space
        $xpos += $pxPerBar;

        // bar
        imagefilledrectangle(
            $this->img,
            $xpos,
            0,
            $xpos + $pxPerBar - 1,
            $this->y,
            $black
        );

        $xpos += $pxPerBar;

        // space
        $xpos += $pxPerBar;

        // Draw right $this->data contents
        for ($idx = 7; $idx < 13; ++$idx)
        {
            $value = substr($this->data, $idx, 1);

            foreach ($this->_codingmap[$value]['C'] as $bar)
            {
                if ($bar)
                {
                    imagefilledrectangle(
                        $this->img,
                        $xpos,
                        0,
                        $xpos + $pxPerBar - 1,
                        $this->y,
                        $black
                    );
                }

                $xpos += $pxPerBar;
            }
        }

        // Draws the right guard pattern (bar-space-bar)
        // bar
        imagefilledrectangle(
            $this->img,
            $xpos,
            0,
            $xpos + $pxPerBar - 1,
            $this->y,
            $black
        );

        $xpos += $pxPerBar;

        // space
        $xpos += $pxPerBar;

        // bar
        imagefilledrectangle(
            $this->img,
            $xpos,
            0,
            $xpos + $pxPerBar - 1,
            $this->y,
            $black
        );
    }
}
?>