void php_filter_validate_email(PHP_INPUT_FILTER_PARAM_DECL) /* {{{ */
{
	/*
	 * The regex below is based on a regex by Michael Rushton.
	 * However, it is not identical.  I changed it to only consider routeable
	 * addresses as valid.  Michael's regex considers a@b a valid address
	 * which conflicts with section 2.3.5 of RFC 5321 which states that:
	 *
	 *   Only resolvable, fully-qualified domain names (FQDNs) are permitted
	 *   when domain names are used in SMTP.  In other words, names that can
	 *   be resolved to MX RRs or address (i.e., A or AAAA) RRs (as discussed
	 *   in Section 5) are permitted, as are CNAME RRs whose targets can be
	 *   resolved, in turn, to MX or address RRs.  Local nicknames or
	 *   unqualified names MUST NOT be used.
	 *
	 * This regex does not handle comments and folding whitespace.  While
	 * this is technically valid in an email address, these parts aren't
	 * actually part of the address itself.
	 *
	 * Michael's regex carries this copyright:
	 *
	 * Copyright © Michael Rushton 2009-10
	 * http://squiloople.com/
	 * Feel free to use and redistribute this code. But please keep this copyright notice.
	 *
	 */
	pcre2_code *re = NULL;
	pcre2_match_data *match_data = NULL;
	uint32_t preg_options = 0, capture_count;
	zend_string *sregexp;
	int rc;
	const char regexp0[] = "/^(?!(?:(?:\\x22?\\x5C[\\x00-\\x7E]\\x22?)|(?:\\x22?[^\\x5C\\x22]\\x22?)){255,})(?!(?:(?:\\x22?\\x5C[\\x00-\\x7E]\\x22?)|(?:\\x22?[^\\x5C\\x22]\\x22?)){65,}@)(?:(?:[\\x21\\x23-\\x27\\x2A\\x2B\\x2D\\x2F-\\x39\\x3D\\x3F\\x5E-\\x7E\\pL\\pN]+)|(?:\\x22(?:[\\x01-\\x08\\x0B\\x0C\\x0E-\\x1F\\x21\\x23-\\x5B\\x5D-\\x7F\\pL\\pN]|(?:\\x5C[\\x00-\\x7F]))*\\x22))(?:\\.(?:(?:[\\x21\\x23-\\x27\\x2A\\x2B\\x2D\\x2F-\\x39\\x3D\\x3F\\x5E-\\x7E\\pL\\pN]+)|(?:\\x22(?:[\\x01-\\x08\\x0B\\x0C\\x0E-\\x1F\\x21\\x23-\\x5B\\x5D-\\x7F\\pL\\pN]|(?:\\x5C[\\x00-\\x7F]))*\\x22)))*@(?:(?:(?!.*[^.]{64,})(?:(?:(?:xn--)?[a-z0-9]+(?:-+[a-z0-9]+)*\\.){1,126}){1,}(?:(?:[a-z][a-z0-9]*)|(?:(?:xn--)[a-z0-9]+))(?:-+[a-z0-9]+)*)|(?:\\[(?:(?:IPv6:(?:(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){7})|(?:(?!(?:.*[a-f0-9][:\\]]){7,})(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){0,5})?::(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){0,5})?)))|(?:(?:IPv6:(?:(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){5}:)|(?:(?!(?:.*[a-f0-9]:){5,})(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){0,3})?::(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){0,3}:)?)))?(?:(?:25[0-5])|(?:2[0-4][0-9])|(?:1[0-9]{2})|(?:[1-9]?[0-9]))(?:\\.(?:(?:25[0-5])|(?:2[0-4][0-9])|(?:1[0-9]{2})|(?:[1-9]?[0-9]))){3}))\\]))$/iDu";
	const char regexp1[] = "/^(?!(?:(?:\\x22?\\x5C[\\x00-\\x7E]\\x22?)|(?:\\x22?[^\\x5C\\x22]\\x22?)){255,})(?!(?:(?:\\x22?\\x5C[\\x00-\\x7E]\\x22?)|(?:\\x22?[^\\x5C\\x22]\\x22?)){65,}@)(?:(?:[\\x21\\x23-\\x27\\x2A\\x2B\\x2D\\x2F-\\x39\\x3D\\x3F\\x5E-\\x7E]+)|(?:\\x22(?:[\\x01-\\x08\\x0B\\x0C\\x0E-\\x1F\\x21\\x23-\\x5B\\x5D-\\x7F]|(?:\\x5C[\\x00-\\x7F]))*\\x22))(?:\\.(?:(?:[\\x21\\x23-\\x27\\x2A\\x2B\\x2D\\x2F-\\x39\\x3D\\x3F\\x5E-\\x7E]+)|(?:\\x22(?:[\\x01-\\x08\\x0B\\x0C\\x0E-\\x1F\\x21\\x23-\\x5B\\x5D-\\x7F]|(?:\\x5C[\\x00-\\x7F]))*\\x22)))*@(?:(?:(?!.*[^.]{64,})(?:(?:(?:xn--)?[a-z0-9]+(?:-+[a-z0-9]+)*\\.){1,126}){1,}(?:(?:[a-z][a-z0-9]*)|(?:(?:xn--)[a-z0-9]+))(?:-+[a-z0-9]+)*)|(?:\\[(?:(?:IPv6:(?:(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){7})|(?:(?!(?:.*[a-f0-9][:\\]]){7,})(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){0,5})?::(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){0,5})?)))|(?:(?:IPv6:(?:(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){5}:)|(?:(?!(?:.*[a-f0-9]:){5,})(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){0,3})?::(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){0,3}:)?)))?(?:(?:25[0-5])|(?:2[0-4][0-9])|(?:1[0-9]{2})|(?:[1-9]?[0-9]))(?:\\.(?:(?:25[0-5])|(?:2[0-4][0-9])|(?:1[0-9]{2})|(?:[1-9]?[0-9]))){3}))\\]))$/iD";
	const char *regexp;
	size_t regexp_len;

	if (flags & FILTER_FLAG_EMAIL_UNICODE) {
		regexp = regexp0;
		regexp_len = sizeof(regexp0) - 1;
	} else {
		regexp = regexp1;
		regexp_len = sizeof(regexp1) - 1;
	}

	/* The maximum length of an e-mail address is 320 octets, per RFC 2821. */
	if (Z_STRLEN_P(value) > 320) {
		RETURN_VALIDATION_FAILED
	}

	sregexp = zend_string_init(regexp, regexp_len, 0);
	re = pcre_get_compiled_regex(sregexp, &capture_count, &preg_options);
	zend_string_release_ex(sregexp, 0);
	if (!re) {
		RETURN_VALIDATION_FAILED
	}
	match_data = php_pcre_create_match_data(capture_count, re);
	if (!match_data) {
		RETURN_VALIDATION_FAILED
	}
	rc = pcre2_match(re, (PCRE2_SPTR)Z_STRVAL_P(value), Z_STRLEN_P(value), 0, preg_options, match_data, php_pcre_mctx());
	php_pcre_free_match_data(match_data);

	/* 0 means that the vector is too small to hold all the captured substring offsets */
	if (rc < 0) {
		RETURN_VALIDATION_FAILED
	}

}
Unknown