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<?php
 /*
 * This file is part of the Symfony package.
 *
 * (c) Fabien Potencier <[email protected]>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */
 
 namespace Symfony\Component\Yaml;
 
 /**
 * Escaper encapsulates escaping rules for single and double-quoted
 * YAML strings.
 *
 * @author Matthew Lewinski <[email protected]>
 *
 * @internal
 */
 class Escaper
 {
 // Characters that would cause a dumped string to require double quoting.
 const REGEX_CHARACTER_TO_ESCAPE = "[\\x00-\\x1f]|\xc2\x85|\xc2\xa0|\xe2\x80\xa8|\xe2\x80\xa9";
 
 // Mapping arrays for escaping a double quoted string. The backslash is
 // first to ensure proper escaping because str_replace operates iteratively
 // on the input arrays. This ordering of the characters avoids the use of strtr,
 // which performs more slowly.
 private static $escapees = array('\\', '\\\\', '\\"', '"',
 "\x00",  "\x01",  "\x02",  "\x03",  "\x04",  "\x05",  "\x06",  "\x07",
 "\x08",  "\x09",  "\x0a",  "\x0b",  "\x0c",  "\x0d",  "\x0e",  "\x0f",
 "\x10",  "\x11",  "\x12",  "\x13",  "\x14",  "\x15",  "\x16",  "\x17",
 "\x18",  "\x19",  "\x1a",  "\x1b",  "\x1c",  "\x1d",  "\x1e",  "\x1f",
 "\xc2\x85", "\xc2\xa0", "\xe2\x80\xa8", "\xe2\x80\xa9",
 );
 private static $escaped = array('\\\\', '\\"', '\\\\', '\\"',
 '\\0',   '\\x01', '\\x02', '\\x03', '\\x04', '\\x05', '\\x06', '\\a',
 '\\b',   '\\t',   '\\n',   '\\v',   '\\f',   '\\r',   '\\x0e', '\\x0f',
 '\\x10', '\\x11', '\\x12', '\\x13', '\\x14', '\\x15', '\\x16', '\\x17',
 '\\x18', '\\x19', '\\x1a', '\\e',   '\\x1c', '\\x1d', '\\x1e', '\\x1f',
 '\\N', '\\_', '\\L', '\\P',
 );
 
 /**
 * Determines if a PHP value would require double quoting in YAML.
 *
 * @param string $value A PHP value
 *
 * @return bool True if the value would require double quotes
 */
 public static function requiresDoubleQuoting($value)
 {
 return 0 < preg_match('/'.self::REGEX_CHARACTER_TO_ESCAPE.'/u', $value);
 }
 
 /**
 * Escapes and surrounds a PHP value with double quotes.
 *
 * @param string $value A PHP value
 *
 * @return string The quoted, escaped string
 */
 public static function escapeWithDoubleQuotes($value)
 {
 return sprintf('"%s"', str_replace(self::$escapees, self::$escaped, $value));
 }
 
 /**
 * Determines if a PHP value would require single quoting in YAML.
 *
 * @param string $value A PHP value
 *
 * @return bool True if the value would require single quotes
 */
 public static function requiresSingleQuoting($value)
 {
 // Determines if a PHP value is entirely composed of a value that would
 // require single quoting in YAML.
 if (in_array(strtolower($value), array('null', '~', 'true', 'false', 'y', 'n', 'yes', 'no', 'on', 'off'))) {
 return true;
 }
 
 // Determines if the PHP value contains any single characters that would
 // cause it to require single quoting in YAML.
 return 0 < preg_match('/[ \s \' " \: \{ \} \[ \] , & \* \# \?] | \A[ \- ? | < > = ! % @ ` ]/x', $value);
 }
 
 /**
 * Escapes and surrounds a PHP value with single quotes.
 *
 * @param string $value A PHP value
 *
 * @return string The quoted, escaped string
 */
 public static function escapeWithSingleQuotes($value)
 {
 return sprintf("'%s'", str_replace('\'', '\'\'', $value));
 }
 }
 
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