wp_kses_hair

	if ( is_array( $allowed_attr[ $name_low ] ) ) {
		// There are some checks.
		foreach ( $allowed_attr[ $name_low ] as $currkey => $currval ) {
			if ( ! wp_kses_check_attr_val( $value, $vless, $currkey, $currval ) ) {
				$name  = '';
				$value = '';
				$whole = '';
				return false;
			}
		}
	}

	return true;
}

/**
 * Builds an attribute list from string containing attributes.
 *
 * This function does a lot of work. It parses an attribute list into an array
 * with attribute data, and tries to do the right thing even if it gets weird
 * input. It will add quotes around attribute values that don't have any quotes
 * or apostrophes around them, to make it easier to produce HTML code that will
 * conform to W3C's HTML specification. It will also remove bad URL protocols
 * from attribute values. It also reduces duplicate attributes by using the
 * attribute defined first (`foo='bar' foo='baz'` will result in `foo='bar'`).
 *
 * @since 1.0.0
 *
 * @param string   $attr              Attribute list from HTML element to closing HTML element tag.
 * @param string[] $allowed_protocols Array of allowed URL protocols.
 * @return array[] Array of attribute information after parsing.
 */
function wp_kses_hair( $attr, $allowed_protocols ) {
	$attrarr  = array();
	$mode     = 0;
	$attrname = '';
	$uris     = wp_kses_uri_attributes();

	// Loop through the whole attribute list.

	while ( strlen( $attr ) != 0 ) {
		$working = 0; // Was the last operation successful?

		switch ( $mode ) {
			case 0:
				if ( preg_match( '/^([_a-zA-Z][-_a-zA-Z0-9:.]*)/', $attr, $match ) ) {
					$attrname = $match[1];
					$working  = 1;
					$mode     = 1;
					$attr     = preg_replace( '/^[_a-zA-Z][-_a-zA-Z0-9:.]*/', '', $attr );
				}

				break;

			case 1:
				if ( preg_match( '/^\s*=\s*/', $attr ) ) { // Equals sign.
					$working = 1;
					$mode    = 2;
					$attr    = preg_replace( '/^\s*=\s*/', '', $attr );
					break;
				}

				if ( preg_match( '/^\s+/', $attr ) ) { // Valueless.
					$working = 1;
					$mode    = 0;
					if ( false === array_key_exists( $attrname, $attrarr ) ) {
						$attrarr[ $attrname ] = array(
							'name'  => $attrname,
							'value' => '',
							'whole' => $attrname,
							'vless' => 'y',
						);
					}
					$attr = preg_replace( '/^\s+/', '', $attr );
				}

				break;

			case 2:
				if ( preg_match( '%^"([^"]*)"(\s+|/?$)%', $attr, $match ) ) {
					// "value"
					$thisval = $match[1];
					if ( in_array( strtolower( $attrname ), $uris, true ) ) {
						$thisval = wp_kses_bad_protocol( $thisval, $allowed_protocols );
					}

					if ( false === array_key_exists( $attrname, $attrarr ) ) {
						$attrarr[ $attrname ] = array(
							'name'  => $attrname,
							'value' => $thisval,
							'whole' => "$attrname=\"$thisval\"",
							'vless' => 'n',
						);
					}
					$working = 1;
					$mode    = 0;
					$attr    = preg_replace( '/^"[^"]*"(\s+|$)/', '', $attr );
					break;
				}

				if ( preg_match( "%^'([^']*)'(\s+|/?$)%", $attr, $match ) ) {
					// 'value'
					$thisval = $match[1];
					if ( in_array( strtolower( $attrname ), $uris, true ) ) {
						$thisval = wp_kses_bad_protocol( $thisval, $allowed_protocols );
					}

					if ( false === array_key_exists( $attrname, $attrarr ) ) {
						$attrarr[ $attrname ] = array(
							'name'  => $attrname,
							'value' => $thisval,
							'whole' => "$attrname='$thisval'",
							'vless' => 'n',
						);
					}
					$working = 1;
					$mode    = 0;
					$attr    = preg_replace( "/^'[^']*'(\s+|$)/", '', $attr );
					break;
				}

				if ( preg_match( "%^([^\s\"']+)(\s+|/?$)%", $attr, $match ) ) {
					// value
					$thisval = $match[1];
					if ( in_array( strtolower( $attrname ), $uris, true ) ) {
						$thisval = wp_kses_bad_protocol( $thisval, $allowed_protocols );
					}

					if ( false === array_key_exists( $attrname, $attrarr ) ) {
						$attrarr[ $attrname ] = array(
							'name'  => $attrname,