wp_kses_hair( string $attr, array $allowed_protocols )

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 : // attribute name, href for instance

				if ( preg_match('/^([-a-zA-Z:]+)/', $attr, $match ) ) {
					$attrname = $match[1];
					$working = $mode = 1;
					$attr = preg_replace( '/^[-a-zA-Z:]+/', '', $attr );
				}

				break;

			case 1 : // equals sign or valueless ("selected")

				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 : // attribute value, a URL after href= for instance

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

					if(false === array_key_exists($attrname, $attrarr)) {
						$attrarr[$attrname] = array ('name' => $attrname, 'value' => $thisval, 'whole' => "$attrname=\"$thisval\"", 'vless' => 'n');
					}
					// We add quotes to conform to W3C's HTML spec.
					$working = 1;
					$mode = 0;
					$attr = preg_replace("%^[^\s\"']+(\s+|$)%", '', $attr);
				}

				break;
		} // switch

		if ($working == 0) // not well formed, remove and try again
		{
			$attr = wp_kses_html_error($attr);
			$mode = 0;
		}
	} // while

	if ($mode == 1 && false === array_key_exists($attrname, $attrarr))
		// special case, for when the attribute list ends with a valueless
		// attribute like "selected"
		$attrarr[$attrname] = array ('name' => $attrname, 'value' => '', 'whole' => $attrname, 'vless' => 'y');

	return $attrarr;
}