<?php
/**
* @package s9e\TextFormatter
* @copyright Copyright (c) 2010-2021 The s9e authors
* @license http://www.opensource.org/licenses/mit-license.php The MIT License
*/
namespace s9e\TextFormatter\Configurator\Validators;
use InvalidArgumentException;
/**
* Attribute name rules:
* - must start with a letter or an underscore
* - can only contain letters, numbers, underscores and dashes
*
* Unprefixed names are normalized to uppercase. Prefixed names are preserved as-is.
*/
abstract class AttributeName
{
/**
* Return whether a string is a valid attribute name
*
* @param string $name
* @return bool
*/
public static function isValid($name)
{
return (bool) preg_match('#^(?!xmlns$)[a-z_][-a-z_0-9]*$#Di', $name);
}
/**
* Normalize a tag name
*
* @throws InvalidArgumentException if the original name is not valid
*
* @param string $name Original name
* @return string Normalized name
*/
public static function normalize($name)
{
if (!static::isValid($name))
{
throw new InvalidArgumentException("Invalid attribute name '" . $name . "'");
}
return strtolower($name);
}
}