Chris@0: <?php
Chris@0: 
Chris@0: /*
Chris@0:  * This file is part of the Symfony package.
Chris@0:  *
Chris@0:  * (c) Fabien Potencier <fabien@symfony.com>
Chris@0:  *
Chris@0:  * For the full copyright and license information, please view the LICENSE
Chris@0:  * file that was distributed with this source code.
Chris@0:  */
Chris@0: 
Chris@0: namespace Symfony\Component\Yaml;
Chris@0: 
Chris@0: use Symfony\Component\Yaml\Exception\ParseException;
Chris@0: 
Chris@0: /**
Chris@0:  * Unescaper encapsulates unescaping rules for single and double-quoted
Chris@0:  * YAML strings.
Chris@0:  *
Chris@0:  * @author Matthew Lewinski <matthew@lewinski.org>
Chris@0:  *
Chris@0:  * @internal
Chris@0:  */
Chris@0: class Unescaper
Chris@0: {
Chris@0:     /**
Chris@0:      * Regex fragment that matches an escaped character in a double quoted string.
Chris@0:      */
Chris@0:     const REGEX_ESCAPED_CHARACTER = '\\\\(x[0-9a-fA-F]{2}|u[0-9a-fA-F]{4}|U[0-9a-fA-F]{8}|.)';
Chris@0: 
Chris@0:     /**
Chris@0:      * Unescapes a single quoted string.
Chris@0:      *
Chris@0:      * @param string $value A single quoted string
Chris@0:      *
Chris@0:      * @return string The unescaped string
Chris@0:      */
Chris@0:     public function unescapeSingleQuotedString($value)
Chris@0:     {
Chris@0:         return str_replace('\'\'', '\'', $value);
Chris@0:     }
Chris@0: 
Chris@0:     /**
Chris@0:      * Unescapes a double quoted string.
Chris@0:      *
Chris@0:      * @param string $value A double quoted string
Chris@0:      *
Chris@0:      * @return string The unescaped string
Chris@0:      */
Chris@0:     public function unescapeDoubleQuotedString($value)
Chris@0:     {
Chris@0:         $callback = function ($match) {
Chris@0:             return $this->unescapeCharacter($match[0]);
Chris@0:         };
Chris@0: 
Chris@0:         // evaluate the string
Chris@0:         return preg_replace_callback('/'.self::REGEX_ESCAPED_CHARACTER.'/u', $callback, $value);
Chris@0:     }
Chris@0: 
Chris@0:     /**
Chris@0:      * Unescapes a character that was found in a double-quoted string.
Chris@0:      *
Chris@0:      * @param string $value An escaped character
Chris@0:      *
Chris@0:      * @return string The unescaped character
Chris@0:      */
Chris@0:     private function unescapeCharacter($value)
Chris@0:     {
Chris@0:         switch ($value[1]) {
Chris@0:             case '0':
Chris@0:                 return "\x0";
Chris@0:             case 'a':
Chris@0:                 return "\x7";
Chris@0:             case 'b':
Chris@0:                 return "\x8";
Chris@0:             case 't':
Chris@0:                 return "\t";
Chris@0:             case "\t":
Chris@0:                 return "\t";
Chris@0:             case 'n':
Chris@0:                 return "\n";
Chris@0:             case 'v':
Chris@0:                 return "\xB";
Chris@0:             case 'f':
Chris@0:                 return "\xC";
Chris@0:             case 'r':
Chris@0:                 return "\r";
Chris@0:             case 'e':
Chris@0:                 return "\x1B";
Chris@0:             case ' ':
Chris@0:                 return ' ';
Chris@0:             case '"':
Chris@0:                 return '"';
Chris@0:             case '/':
Chris@0:                 return '/';
Chris@0:             case '\\':
Chris@0:                 return '\\';
Chris@0:             case 'N':
Chris@0:                 // U+0085 NEXT LINE
Chris@0:                 return "\xC2\x85";
Chris@0:             case '_':
Chris@0:                 // U+00A0 NO-BREAK SPACE
Chris@0:                 return "\xC2\xA0";
Chris@0:             case 'L':
Chris@0:                 // U+2028 LINE SEPARATOR
Chris@0:                 return "\xE2\x80\xA8";
Chris@0:             case 'P':
Chris@0:                 // U+2029 PARAGRAPH SEPARATOR
Chris@0:                 return "\xE2\x80\xA9";
Chris@0:             case 'x':
Chris@0:                 return self::utf8chr(hexdec(substr($value, 2, 2)));
Chris@0:             case 'u':
Chris@0:                 return self::utf8chr(hexdec(substr($value, 2, 4)));
Chris@0:             case 'U':
Chris@0:                 return self::utf8chr(hexdec(substr($value, 2, 8)));
Chris@0:             default:
Chris@0:                 throw new ParseException(sprintf('Found unknown escape character "%s".', $value));
Chris@0:         }
Chris@0:     }
Chris@0: 
Chris@0:     /**
Chris@0:      * Get the UTF-8 character for the given code point.
Chris@0:      *
Chris@0:      * @param int $c The unicode code point
Chris@0:      *
Chris@0:      * @return string The corresponding UTF-8 character
Chris@0:      */
Chris@0:     private static function utf8chr($c)
Chris@0:     {
Chris@0:         if (0x80 > $c %= 0x200000) {
Chris@17:             return \chr($c);
Chris@0:         }
Chris@0:         if (0x800 > $c) {
Chris@17:             return \chr(0xC0 | $c >> 6).\chr(0x80 | $c & 0x3F);
Chris@0:         }
Chris@0:         if (0x10000 > $c) {
Chris@17:             return \chr(0xE0 | $c >> 12).\chr(0x80 | $c >> 6 & 0x3F).\chr(0x80 | $c & 0x3F);
Chris@0:         }
Chris@0: 
Chris@17:         return \chr(0xF0 | $c >> 18).\chr(0x80 | $c >> 12 & 0x3F).\chr(0x80 | $c >> 6 & 0x3F).\chr(0x80 | $c & 0x3F);
Chris@0:     }
Chris@0: }