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