_normalize_entities() regular expression.
 *
 * This function only accepts valid named entity references, which are finite,
 * case-sensitive, and highly scrutinized by HTML and XML validators.
 *
 * @since 3.0.0
 *
 * @global array $allowedentitynames
 *
 * @param array $matches preg_replace_callback() matches array
 * @return string Correctly encoded entity
 */
function wp_kses_named_entities($matches) {
	global $allowedentitynames;

	if ( empty($matches[1]) )
		return '';

	$i = $matches[1];
	return ( ! in_array( $i, $allowedentitynames ) ) ? "&$i;" : "&$i;";
}

/**
 * Callback for wp_kses_normalize_entities() regular expression.
 *
 * This function helps wp_kses_normalize_entities() to only accept 16-bit
 * values and nothing more for `&#number;` entities.
 *
 * @access private
 * @since 1.0.0
 *
 * @param array $matches preg_replace_callback() matches array
 * @return string Correctly encoded entity
 */
function wp_kses_normalize_entities2($matches) {
	if ( empty($matches[1]) )
		return '';

	$i = $matches[1];
	if (valid_unicode($i)) {
		$i = str_pad(ltrim($i,'0'), 3, '0', STR_PAD_LEFT);
		$i = "&#$i;";
	} else {
		$i = "&#$i;";
	}

	return $i;
}

/**
 * Callback for wp_kses_normalize_entities() for regular expression.
 *
 * This function helps wp_kses_normalize_entities() to only accept valid Unicode
 * numeric entities in hex form.
 *
 * @since 2.7.0
 * @access private
 *
 * @param array $matches preg_replace_callback() matches array
 * @return string Correctly encoded entity
 */
function wp_kses_normalize_entities3($matches) {
	if ( empty($matches[1]) )
		return '';

	$hexchars = $matches[1];
	return ( ! valid_unicode( hexdec( $hexchars ) ) ) ? "&#x$hexchars;" : '&#x'.ltrim($hexchars,'0').';';
}

/**
 * Helper function to determine if a Unicode value is valid.
 *
 * @since 2.7.0
 *
 * @param int $i Unicode value
 * @return bool True if the value was a valid Unicode number
 */
function valid_unicode($i) {
	return ( $i == 0x9 || $i == 0xa || $i == 0xd ||
			($i >= 0x20 && $i <= 0xd7ff) ||
			($i >= 0xe000 && $i <= 0xfffd) ||
			($i >= 0x10000 && $i <= 0x10ffff) );
}

/**
 * Convert all entities to their character counterparts.
 *
 * This function decodes numeric HTML entities (`&#65;` and `&#x41;`).
 * It doesn't do anything with other entities like &auml;, but we don't
 * need them in the URL protocol whitelisting system anyway.
 *
 * @since 1.0.0
 *
 * @param string $string Content to change entities
 * @return string Content after decoded entities
 */
function wp_kses_decode_entities($string) {
	$string = preg_replace_callback('/&#([0-9]+);/', '_wp_kses_decode_entities_chr', $string);
	$string = preg_replace_callback('/&#[Xx]([0-9A-Fa-f]+);/', '_wp_kses_decode_entities_chr_hexdec', $string);

	return $string;
}

/**
 * Regex callback for wp_kses_decode_entities()
 *
 * @since 2.9.0
 *
 * @param array $match preg match
 * @return string
 */
function _wp_kses_decode_entities_chr( $match ) {
	return chr( $match[1] );
}

/**
 * Regex callback for wp_kses_decode_entities()
 *
 * @since 2.9.0
 *
 * @param array $match preg match
 * @return string
 */
function _wp_kses_decode_entities_chr_hexdec( $match ) {
	return chr( hexdec( $match[1] ) );
}

/**
 * Sanitize content with allowed HTML Kses rules.
 *
 * @since 1.0.0
 *
 * @param string $data Content to filter, expected to be escaped with slashes
 * @return string Filtered content
 */
function wp_filter_kses( $data ) {
	return addslashes( wp_kses( stripslashes( $data ), current_filter() ) );
}

/**
 * Sanitize content with allowed HTML Kses rules.
 *
 * @since 2.9.0
 *
 * @param string $data Content to filter, expected to not be escaped
 * @return string Filtered content
 */
function wp_kses_data( $data ) {
	return wp_kses( $data, current_filter() );
}

/**
 * Sanitize content for allowed HTML tags for post content.
 *
 * Post content refers to the page contents of the 'post' type and not $_POST
 * data from forms.
 *
 * @since 2.0.0
 *
 * @param string $data Post content to filter, expected to be escaped with slashes
 * @return string Filtered post content with allowed HTML tags and attributes intact.
 */
function wp_filter_post_kses( $data ) {
	return addslashes( wp_kses( stripslashes( $data ), 'post' ) );
}

/**
 * Sanitize content for allowed HTML tags for post content.
 *
 * Post content refers to the page contents of the 'post' type and not $_POST
 * data from forms.
 *
 * @since 2.9.0
 *
 * @param string $data Post content to filter
 * @return string Filtered post content with allowed HTML tags and attributes intact.
 */
function wp_kses_post( $data ) {
	return wp_kses( $data, 'post' );
}

/**
 * Navigates through an array, object, or scalar, and sanitizes content for
 * allowed HTML tags for post content.
 *
 * @since 4.4.2
 *
 * @see map_deep()
 *
 * @param mixed $data The array, object, or scalar value to inspect.
 * @return mixed The filtered content.
 */
function wp_kses_post_deep( $data ) {
	return map_deep( $data, 'wp_kses_post' );
}

/**
 * Strips all of the HTML in the content.
 *
 * @since 2.1.0
 *
 * @param string $data Content to strip all HTML from
 * @return string Filtered content without any HTML
 */
function wp_filter_nohtml_kses( $data ) {
	return addslashes( wp_kses( stripslashes( $data ), 'strip' ) );
}

/**
 * Adds all Kses input form content filters.
 *
 * All hooks have default priority. The wp_filter_kses() function is added to
 * the 'pre_comment_content' and 'title_save_pre' hooks.
 *
 * The wp_filter_post_kses() function is added to the 'content_save_pre',
 * 'excerpt_save_pre', and 'content_filtered_save_pre' hooks.
 *
 * @since 2.0.0
 */
function kses_init_filters() {
	// Normal filtering
	add_filter('title_save_pre', 'wp_filter_kses');

	// Comment filtering
	if ( current_user_can( 'unfiltered_html' ) )
		add_filter( 'pre_comment_content', 'wp_filter_post_kses' );
	else
		add_filter( 'pre_comment_content', 'wp_filter_kses' );

	// Post filtering
	add_filter('content_save_pre', 'wp_filter_post_kses');
	add_filter('excerpt_save_pre', 'wp_filter_post_kses');
	add_filter('content_filtered_save_pre', 'wp_filter_post_kses');
}

/**
 * Removes all Kses input form content filters.
 *
 * A quick procedural method to removing all of the filters that kses uses for
 * content in WordPress Loop.
 *
 * Does not remove the kses_init() function from {@see 'init'} hook (priority is
 * default). Also does not remove kses_init() function from {@see 'set_current_user'}
 * hook (priority is also default).
 *
 * @since 2.0.6
 */
function kses_remove_filters() {
	// Normal filtering
	remove_filter('title_save_pre', 'wp_filter_kses');

	// Comment filtering
	remove_filter( 'pre_comment_content', 'wp_filter_post_kses' );
	remove_filter( 'pre_comment_content', 'wp_filter_kses' );

	// Post filtering
	remove_filter('content_save_pre', 'wp_filter_post_kses');
	remove_filter('excerpt_save_pre', 'wp_filter_post_kses');
	remove_filter('content_filtered_save_pre', 'wp_filter_post_kses');
}

/**
 * Sets up most of the Kses filters for input form content.
 *
 * If you remove the kses_init() function from {@see 'init'} hook and
 * {@see 'set_current_user'} (priority is default), then none of the Kses filter hooks
 * will be added.
 *
 * First removes all of the Kses filters in case the current user does not need
 * to have Kses filter the content. If the user does not have unfiltered_html
 * capability, then Kses filters are added.
 *
 * @since 2.0.0
 */
function kses_init() {
	kses_remove_filters();

	if ( ! current_user_can( 'unfiltered_html' ) ) {
		kses_init_filters();
	}
}

/**
 * Inline CSS filter
 *
 * @since 2.8.1
 *
 * @param string $css        A string of CSS rules.
 * @param string $deprecated Not used.
 * @return string            Filtered string of CSS rules.
 */
function safecss_filter_attr( $css, $deprecated = '' ) {
	if ( !empty( $deprecated ) )
		_deprecated_argument( __FUNCTION__, '2.8.1' ); // Never implemented

	$css = wp_kses_no_null($css);
	$css = str_replace(array("\n","\r","\t"), '', $css);

	if ( preg_match( '%[\\\\(&=}]|/\*%', $css ) ) // remove any inline css containing \ ( & } = or comments
		return '';

	$css_array = explode( ';', trim( $css ) );

	/**
	 * Filters list of allowed CSS attributes.
	 *
	 * @since 2.8.1
	 * @since 4.4.0 Added support for `min-height`, `max-height`, `min-width`, and `max-width`.
	 * @since 4.6.0 Added support for `list-style-type`.
	 *
	 * @param array $attr List of allowed CSS attributes.
	 */
	$allowed_attr = apply_filters( 'safe_style_css', array(
		'background',
		'background-color',

		'border',
		'border-width',
		'border-color',
		'border-style',
		'border-right',
		'border-right-color',
		'border-right-style',
		'border-right-width',
		'border-bottom',
		'border-bottom-color',
		'border-bottom-style',
		'border-bottom-width',
		'border-left',
		'border-left-color',
		'border-left-style',
		'border-left-width',
		'border-top',
		'border-top-color',
		'border-top-style',
		'border-top-width',

		'border-spacing',
		'border-collapse',
		'caption-side',

		'color',
		'font',
		'font-family',
		'font-size',
		'font-style',
		'font-variant',
		'font-weight',
		'letter-spacing',
		'line-height',
		'text-decoration',
		'text-indent',
		'text-align',

		'height',
		'min-height',
		'max-height',

		'width',
		'min-width',
		'max-width',

		'margin',
		'margin-right',
		'margin-bottom',
		'margin-left',
		'margin-top',

		'padding',
		'padding-right',
		'padding-bottom',
		'padding-left',
		'padding-top',

		'clear',
		'cursor',
		'direction',
		'float',
		'overflow',
		'vertical-align',
		'list-style-type',
	) );

	if ( empty($allowed_attr) )
		return $css;

	$css = '';
	foreach ( $css_array as $css_item ) {
		if ( $css_item == '' )
			continue;
		$css_item = trim( $css_item );
		$found = false;
		if ( strpos( $css_item, ':' ) === false ) {
			$found = true;
		} else {
			$parts = explode( ':', $css_item );
			if ( in_array( trim( $parts[0] ), $allowed_attr ) )
				$found = true;
		}
		if ( $found ) {
			if( $css != '' )
				$css .= ';';
			$css .= $css_item;
		}
	}

	return $css;
}

/**
 * Helper function to add global attributes to a tag in the allowed html list.
 *
 * @since 3.5.0
 * @access private
 *
 * @param array $value An array of attributes.
 * @return array The array of attributes with global attributes added.
 */
function _wp_add_global_attributes( $value ) {
	$global_attributes = array(
		'class' => true,
		'id' => true,
		'style' => true,
		'title' => true,
		'role' => true,
	);

	if ( true === $value )
		$value = array();

	if ( is_array( $value ) )
		return array_merge( $value, $global_attributes );

	return $value;
}