<?php

/**

 * Zend Framework

 *

 * LICENSE

 *

 * This source file is subject to the new BSD license that is bundled

 * with this package in the file LICENSE.txt.

 * It is also available through the world-wide-web at this URL:

 * http://framework.zend.com/license/new-bsd

 * If you did not receive a copy of the license and are unable to

 * obtain it through the world-wide-web, please send an email

 * to license@zend.com so we can send you a copy immediately.

 *

 * @category   Zend

 * @package    Zend_Pdf

 * @copyright  Copyright (c) 2005-2010 Zend Technologies USA Inc. (http://www.zend.com)

 * @license    http://framework.zend.com/license/new-bsd     New BSD License

 * @version    $Id: String.php 21542 2010-03-18 08:56:40Z bate $

 */

/** Zend_Pdf_Element */

require_once 'Zend/Pdf/Element.php';

/**

 * PDF file 'string' element implementation

 *

 * @category   Zend

 * @package    Zend_Pdf

 * @copyright  Copyright (c) 2005-2010 Zend Technologies USA Inc. (http://www.zend.com)

 * @license    http://framework.zend.com/license/new-bsd     New BSD License

 */

class Zend_Pdf_Element_String extends Zend_Pdf_Element

{

    /**

     * Object value

     *

     * @var string

     */

    public $value;

    /**

     * Object constructor

     *

     * @param string $val

     */

    public function __construct($val)

    {

        $this->value   = (string)$val;

    }

    /**

     * Return type of the element.

     *

     * @return integer

     */

    public function getType()

    {

        return Zend_Pdf_Element::TYPE_STRING;

    }

    /**

     * Return object as string

     *

     * @param Zend_Pdf_Factory $factory

     * @return string

     */

    public function toString($factory = null)

    {

        return '(' . self::escape((string)$this->value) . ')';

    }

    /**

     * Escape string according to the PDF rules

     *

     * @param string $str

     * @return string

     */

    public static function escape($str)

    {

        $outEntries = array();

        foreach (str_split($str, 128) as $chunk) {

            // Collect sequence of unescaped characters

            $offset = strcspn($chunk, "\n\r\t\x08\x0C()\\");

            $chunkOut = substr($chunk, 0, $offset);

            while ($offset < strlen($chunk)) {

                $nextCode = ord($chunk[$offset++]);

                switch ($nextCode) {

                    // "\n" - line feed (LF)

                    case 10:

                        $chunkOut .= '\\n';

                        break;

                    // "\r" - carriage return (CR)

                    case 13:

                        $chunkOut .= '\\r';

                        break;

                    // "\t" - horizontal tab (HT)

                    case 9:

                        $chunkOut .= '\\t';

                        break;

                    // "\b" - backspace (BS)

                    case 8:

                        $chunkOut .= '\\b';

                        break;

                    // "\f" - form feed (FF)

                    case 12:

                        $chunkOut .= '\\f';

                        break;

                    // '(' - left paranthesis

                    case 40:

                        $chunkOut .= '\\(';

                        break;

                    // ')' - right paranthesis

                    case 41:

                        $chunkOut .= '\\)';

                        break;

                    // '\' - backslash

                    case 92:

                        $chunkOut .= '\\\\';

                        break;

                    default:

                        // This code is never executed extually

                        //

                        // Don't use non-ASCII characters escaping

                        // if ($nextCode >= 32 && $nextCode <= 126 ) {

                        //     // Visible ASCII symbol

                        //     $chunkEntries[] = chr($nextCode);

                        // } else {

                        //     $chunkEntries[] = sprintf('\\%03o', $nextCode);

                        // }

                        break;

                }

                // Collect sequence of unescaped characters

                $start = $offset;

                $offset += strcspn($chunk, "\n\r\t\x08\x0C()\\", $offset);

                $chunkOut .= substr($chunk, $start, $offset - $start);

            }

            $outEntries[] = $chunkOut;

        }

        return implode("\\\n", $outEntries);

    }

    /**

     * Unescape string according to the PDF rules

     *

     * @param string $str

     * @return string

     */

    public static function unescape($str)

    {

        $outEntries = array();

        $offset = 0;

        while ($offset < strlen($str)) {

            // Searche for the next escaped character/sequence

            $escapeCharOffset = strpos($str, '\\', $offset);

            if ($escapeCharOffset === false  ||  $escapeCharOffset == strlen($str) - 1) {

                // There are no escaped characters or '\' char has came at the end of string

                $outEntries[] = substr($str, $offset);

                break;

            } else {

                // Collect unescaped characters sequence

                $outEntries[] = substr($str, $offset, $escapeCharOffset - $offset);

                // Go to the escaped character

                $offset = $escapeCharOffset + 1;

                switch ($str[$offset]) {

                    // '\\n' - line feed (LF)

                    case 'n':

                        $outEntries[] = "\n";

                        break;

                    // '\\r' - carriage return (CR)

                    case 'r':

                        $outEntries[] = "\r";

                        break;

                    // '\\t' - horizontal tab (HT)

                    case 't':

                        $outEntries[] = "\t";

                        break;

                    // '\\b' - backspace (BS)

                    case 'b':

                        $outEntries[] = "\x08";

                        break;

                    // '\\f' - form feed (FF)

                    case 'f':

                        $outEntries[] = "\x0C";

                        break;

                    // '\\(' - left paranthesis

                    case '(':

                        $outEntries[] = '(';

                        break;

                    // '\\)' - right paranthesis

                    case ')':

                        $outEntries[] = ')';

                        break;

                    // '\\\\' - backslash

                    case '\\':

                        $outEntries[] = '\\';

                        break;

                    // "\\\n" or "\\\n\r"

                    case "\n":

                        // skip new line symbol

                        if ($str[$offset + 1] == "\r") {

                            $offset++;

                        }

                        break;

                    default:

                        if (strpos('0123456789', $str[$offset]) !== false) {

                            // Character in octal representation

                            // '\\xxx'

                            $nextCode = '0' . $str[$offset];

                            if (strpos('0123456789', $str[$offset + 1]) !== false) {

                                $nextCode .= $str[++$offset];

                                if (strpos('0123456789', $str[$offset + 1]) !== false) {

                                    $nextCode .= $str[++$offset];

                                }

                            }

                            $outEntries[] = chr(octdec($nextCode));

                        } else {

                            $outEntries[] = $str[$offset];

                        }

                        break;

                }

                $offset++;

            }

        }

        return implode($outEntries);

    }

}