/*
    Adobe Systems Incorporated(r) Source Code License Agreement
    Copyright(c) 2005 Adobe Systems Incorporated. All rights reserved.
    
    Please read this Source Code License Agreement carefully before using
    the source code.
    
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    distribute this source code and such derivative works in source or 
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    code.
    
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    ANY TECHNICAL SUPPORT OR ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING,
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*/

package com.adobe.xml.syndication
{
    import com.adobe.xml.syndication.rss.Category;
    import mx.utils.StringUtil;

    /**
     * Utility class with functions to help parse RSS and Atom feeds.
     * 
     * @langversion ActionScript 3.0
     * @playerversion Flash 8.5
     * @tiptext
     */    
    public class ParsingTools
    {
        /**
         * Checks to see if a piece of XML that should be a string is empty.
         * If so, returns null.
         * 
         * @param x The piece of XML to test.
         * @return null if the string is emply, otherwise the value of the XML
         *         node.
         *
         * @langversion ActionScript 3.0
         * @playerversion Flash 8.5
         * @tiptext
         */
        public static function nullCheck(x:XMLList):String
        {
            var s:String = String(x);
            if (StringUtil.trim(s).length == 0)
            {
                return null;
            }
            return s;
        }

        /**
         * Checks to see if a piece of XML that should be a number is empty.
         * If so, returns NaN.
         * 
         * @param x The piece of XML to test.
         * @return null if the number is emply, otherwise the value of the XML
         *         node.
         *
         * @langversion ActionScript 3.0
         * @playerversion Flash 8.5
         * @tiptext
         */
        public static function nanCheck(x:XMLList):Number
        {
            var s:String = String(x);
            if (ParsingTools.nullCheck(x) == null || s.search(/\d/) == -1)
            {
                return NaN;
            }
            return Number(s);
        }

        /**
         * Checks to see if a piece of XML that should be a date is empty.
         * If so, returns null. If not, parses the string into a date using
         * the specifid date parsing function.
         * 
         * @param x The piece of XML to test.
         * @param f The date parsing function to use to parse the string if
         *          it's not null.
         * @return null if the date is emply, otherwise a date object created
         *         using the specified date-parsing function.
         *
         * @langversion ActionScript 3.0
         * @playerversion Flash 8.5
         * @tiptext
         */
        public static function dateCheck(x:XMLList, f:Function):Date
        {
            var s:String = String(x);
            if (ParsingTools.nullCheck(x) == null)
            {
                return null;
            }
            return f(s);
        }

        /**
         * Checks to see if a piece of XML that should be a string represents
         * categories. If it's empty, return null. If not, parse the string
         * into an array of category objects.
         * 
         * @param x The piece of XML to test.
         * @return null if the string is empty, otherwise an array of Category
         *         objects.
         *
         * @langversion ActionScript 3.0
         * @playerversion Flash 8.5
         * @tiptext
         */
        public static function xmlToCategories(x:XMLList):Array
        {
            if (ParsingTools.nullCheck(x) == null)
            {
                return null;
            }
            var categories:Array = new Array();
            var c:XML;
            for each (c in x)
            {
                var cat:Category = new Category();
                var domain:String = String(c.@domain);
                if (StringUtil.trim(domain).length != 0)
                {
                    cat.domain = domain;
                }
                cat.addPaths(String(c).split("/"));
                categories.push(cat);
            }
            return categories;
        }
    }
}