1: <?php
  2: 
  3: /*
  4:  * This file is part of the Symfony package.
  5:  *
  6:  * (c) Fabien Potencier <fabien@symfony.com>
  7:  *
  8:  * For the full copyright and license information, please view the LICENSE
  9:  * file that was distributed with this source code.
 10:  */
 11: 
 12: namespace Symfony\Component\Yaml;
 13: 
 14: /**
 15:  * Unescaper encapsulates unescaping rules for single and double-quoted
 16:  * YAML strings.
 17:  *
 18:  * @author Matthew Lewinski <matthew@lewinski.org>
 19:  */
 20: class Unescaper
 21: {
 22:     // Parser and Inline assume UTF-8 encoding, so escaped Unicode characters
 23:     // must be converted to that encoding.
 24:     // @deprecated since 2.5, to be removed in 3.0
 25:     const ENCODING = 'UTF-8';
 26: 
 27:     // Regex fragment that matches an escaped character in a double quoted
 28:     // string.
 29:     const REGEX_ESCAPED_CHARACTER = "\\\\([0abt\tnvfre \\\"\\/\\\\N_LP]|x[0-9a-fA-F]{2}|u[0-9a-fA-F]{4}|U[0-9a-fA-F]{8})";
 30: 
 31:     /**
 32:      * Unescapes a single quoted string.
 33:      *
 34:      * @param string $value A single quoted string.
 35:      *
 36:      * @return string The unescaped string.
 37:      */
 38:     public function unescapeSingleQuotedString($value)
 39:     {
 40:         return str_replace('\'\'', '\'', $value);
 41:     }
 42: 
 43:     /**
 44:      * Unescapes a double quoted string.
 45:      *
 46:      * @param string $value A double quoted string.
 47:      *
 48:      * @return string The unescaped string.
 49:      */
 50:     public function unescapeDoubleQuotedString($value)
 51:     {
 52:         $self = $this;
 53:         $callback = function ($match) use ($self) {
 54:             return $self->unescapeCharacter($match[0]);
 55:         };
 56: 
 57:         // evaluate the string
 58:         return preg_replace_callback('/'.self::REGEX_ESCAPED_CHARACTER.'/u', $callback, $value);
 59:     }
 60: 
 61:     /**
 62:      * Unescapes a character that was found in a double-quoted string.
 63:      *
 64:      * @param string $value An escaped character
 65:      *
 66:      * @return string The unescaped character
 67:      */
 68:     public function unescapeCharacter($value)
 69:     {
 70:         switch ($value{1}) {
 71:             case '0':
 72:                 return "\x0";
 73:             case 'a':
 74:                 return "\x7";
 75:             case 'b':
 76:                 return "\x8";
 77:             case 't':
 78:                 return "\t";
 79:             case "\t":
 80:                 return "\t";
 81:             case 'n':
 82:                 return "\n";
 83:             case 'v':
 84:                 return "\xB";
 85:             case 'f':
 86:                 return "\xC";
 87:             case 'r':
 88:                 return "\r";
 89:             case 'e':
 90:                 return "\x1B";
 91:             case ' ':
 92:                 return ' ';
 93:             case '"':
 94:                 return '"';
 95:             case '/':
 96:                 return '/';
 97:             case '\\':
 98:                 return '\\';
 99:             case 'N':
100:                 // U+0085 NEXT LINE
101:                 return "\xC2\x85";
102:             case '_':
103:                 // U+00A0 NO-BREAK SPACE
104:                 return "\xC2\xA0";
105:             case 'L':
106:                 // U+2028 LINE SEPARATOR
107:                 return "\xE2\x80\xA8";
108:             case 'P':
109:                 // U+2029 PARAGRAPH SEPARATOR
110:                 return "\xE2\x80\xA9";
111:             case 'x':
112:                 return self::utf8chr(hexdec(substr($value, 2, 2)));
113:             case 'u':
114:                 return self::utf8chr(hexdec(substr($value, 2, 4)));
115:             case 'U':
116:                 return self::utf8chr(hexdec(substr($value, 2, 8)));
117:         }
118:     }
119: 
120:     /**
121:      * Get the UTF-8 character for the given code point.
122:      *
123:      * @param int $c The unicode code point
124:      *
125:      * @return string The corresponding UTF-8 character
126:      */
127:     private static function utf8chr($c)
128:     {
129:         if (0x80 > $c %= 0x200000) {
130:             return chr($c);
131:         }
132:         if (0x800 > $c) {
133:             return chr(0xC0 | $c >> 6).chr(0x80 | $c & 0x3F);
134:         }
135:         if (0x10000 > $c) {
136:             return chr(0xE0 | $c >> 12).chr(0x80 | $c >> 6 & 0x3F).chr(0x80 | $c & 0x3F);
137:         }
138: 
139:         return chr(0xF0 | $c >> 18).chr(0x80 | $c >> 12 & 0x3F).chr(0x80 | $c >> 6 & 0x3F).chr(0x80 | $c & 0x3F);
140:     }
141: }
142: