<?php
/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements. See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 *
 *	   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * @package log4php
 */

/**
 * Contains various helper methods.
 * 
 * @package log4php
 * @subpackage helpers
 * @since 2.3
 */
class LoggerUtils {
	
	/**
 	 * Splits a fully qualified class name into fragments delimited by the 
 	 * namespace separator (\). 
 	 * 
 	 * For backward compatibility, a dot (.) can be used as a delimiter as
 	 * well. 
	 * 
	 * @param string $name
	 * 
	 * @return array Class name split into fragments.
	 */
	public static function tokenizeClassName($name) {
		$name = str_replace('.', '\\', $name);
		$name = trim($name, ' \\');
		$fragments = explode('\\', $name);
		
		foreach($fragments as $key => $fragment) {
			if (trim($fragment) === '') {
				unset($fragments[$key]);
			}
		}
		
		return $fragments;
	}
	
	/**
	 * Attempts to shorten the given class name to the desired length.
	 * 
	 * This is done by separating the class name into fragments (delimited
	 * by \ or .) and trimming individual fragments, starting with the left,
	 * until desired length has been reached. 
	 * 
	 * The final fragment (i.e. class name) will never be shortened so the 
	 * result may still be longer than given length.
	 * 
	 * @param string $name The (qualified) class name.  
	 * @param integer $length The length to shorten to. If null or 0 is given,
	 * the name will be returned without shortening. 
	 */
	public static function shortenClassName($name, $length) {
		if ($length === null || $length < 0) {
			return $name;
		}
		
		$name = str_replace('.', '\\', $name);
		$name = trim($name, ' \\');
		
		// Check if any shortening is required
		$currentLength = strlen($name);
		if ($currentLength <= $length) {
			return $name;
		}
	
		// Split name into fragments
		$fragments = explode('\\', $name);

		// If zero length is specified, return only last fragment
		if ($length == 0) {
			return array_pop($fragments);
		}
		
		// If the name splits to only one fragment, then it cannot be shortened
		$count = count($fragments);
		if ($count == 1) {
			return $name;
		}
	
		foreach($fragments as $key => &$fragment) {
	
			// Never shorten last fragment
			if ($key == $count - 1) {
				break;
			}
	
			// Check for empty fragments (shouldn't happen but it's possible)
			$fragLen = strlen($fragment);
			if ($fragLen <= 1) {
				continue;
			}
	
			// Shorten fragment to one character and check if total length satisfactory
			$fragment = substr($fragment, 0, 1);
			$currentLength = $currentLength - $fragLen + 1;
	
			if ($currentLength <= $length) {
				break;
			}
		}
		unset($fragment);
	
		return implode('\\', $fragments);
	}
}