<?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);
  	}
  }