stringutil.as.svn-base

一个2D基于verlet的Flash物理引擎。它用AS3编写而成。Fisix的目标是应用到游戏等计算量很大的实时应用中。尽管flash比c/c++要慢,很棒的物理引擎

////////////////////////////////////////////////////////////////////////////////
//
//  Copyright (C) 2003-2007 Adobe Systems Incorporated
//  All Rights Reserved. The following is Source Code and is subject to all
//  restrictions on such code as contained in the End User License Agreement
//  accompanying this product.
//
////////////////////////////////////////////////////////////////////////////////

package org.ascollada.utils
{
	/**
	 *  The StringUtil utility class is an all-static class with methods for
	 *  working with String objects within Flex.
	 *  You do not create instances of StringUtil;
	 *  instead you call methods such as 
	 *  the <code>StringUtil.substitute()</code> method.  
	 */
	public class StringUtil
	{
	    //--------------------------------------------------------------------------
	    //
	    //  Class methods
	    //
	    //--------------------------------------------------------------------------
	
	    /**
	     *  Removes all whitespace characters from the beginning and end
	     *  of the specified string.
	     *
	     *  @param str The String whose whitespace should be trimmed. 
	     *
	     *  @return Updated String where whitespace was removed from the 
	     *  beginning and end. 
	     */
	    public static function trim(str:String):String
	    {
	        var startIndex:int = 0;
	        while (isWhitespace(str.charAt(startIndex)))
	            ++startIndex;
	
	        var endIndex:int = str.length - 1;
	        while (isWhitespace(str.charAt(endIndex)))
	            --endIndex;
	
	        if (endIndex >= startIndex)
	            return str.slice(startIndex, endIndex + 1);
	        else
	            return "";
	    }
	    
	    /**
	     *  Removes all whitespace characters from the beginning and end
	     *  of each element in an Array, where the Array is stored as a String. 
	     *
	     *  @param value The String whose whitespace should be trimmed. 
	     *
	     *  @param separator The String that delimits each Array element in the string.
	     *
	     *  @return Updated String where whitespace was removed from the 
	     *  beginning and end of each element. 
	     */
	    public static function trimArrayElements(value:String, delimiter:String):String
	    {
	        if (value != "" && value != null)
	        {
	            var items:Array = value.split(delimiter);
	            
	            var len:int = items.length;
	            for (var i:int = 0; i < len; i++)
	            {
	                items[i] = StringUtil.trim(items[i]);
	            }
	            
	            if (len > 0)
	            {
	                value = items.join(delimiter);
	            }
	        }
	        
	        return value;
	    }
	
	    /**
	     *  Returns <code>true</code> if the specified string is
	     *  a single space, tab, carriage return, newline, or formfeed character.
	     *
	     *  @param str The String that is is being queried. 
	     *
	     *  @return <code>true</code> if the specified string is
	     *  a single space, tab, carriage return, newline, or formfeed character.
	     */
	    public static function isWhitespace(character:String):Boolean
	    {
	        switch (character)
	        {
	            case " ":
	            case "\t":
	            case "\r":
	            case "\n":
	            case "\f":
	                return true;
	
	            default:
	                return false;
	        }
	    }
	
	    /**
	     *  Substitutes "{n}" tokens within the specified string
	     *  with the respective arguments passed in.
	     *
	     *  @param str The string to make substitutions in.
	     *  This string can contain special tokens of the form
	     *  <code>{n}</code>, where <code>n</code> is a zero based index,
	     *  that will be replaced with the additional parameters
	     *  found at that index if specified.
	     *
	     *  @param rest Additional parameters that can be substituted
	     *  in the <code>str</code> parameter at each <code>{n}</code>
	     *  location, where <code>n</code> is an integer (zero based)
	     *  index value into the array of values specified.
	     *  If the first parameter is an array this array will be used as
	     *  a parameter list.
	     *  This allows reuse of this routine in other methods that want to
	     *  use the ... rest signature.
	     *  For example <pre>
	     *     public function myTracer(str:String, ... rest):void
	     *     { 
	     *         label.text += StringUtil.substitute(str, rest) + "\n";
	     *     } </pre>
	     *
	     *  @return New string with all of the <code>{n}</code> tokens
	     *  replaced with the respective arguments specified.
	     *
	     *  @example
	     *
	     *  var str:String = "here is some info '{0}' and {1}";
	     *  trace(StringUtil.substitute(str, 15.4, true));
	     *
	     *  // this will output the following string:
	     *  // "here is some info '15.4' and true"
	     */
	    public static function substitute(str:String, ... rest):String
	    {
	        // Replace all of the parameters in the msg string.
	        var len:uint = rest.length;
	        var args:Array;
	        if (len == 1 && rest[0] is Array)
	        {
	            args = rest[0] as Array;
	            len = args.length;
	        }
	        else
	        {
	            args = rest;
	        }
	        
	        for (var i:int = 0; i < len; i++)
	        {
	            str = str.replace(new RegExp("\\{"+i+"\\}", "g"), args[i]);
	        }
	
	        return str;
	    }
	}

}