System.IO.Packaging.PackUriHelper.ComparePackUri C# (CSharp) Method

        public static int ComparePackUri(Uri firstPackUri, Uri secondPackUri)
        {
            if (firstPackUri == null)
                return secondPackUri == null ? 0 : -1;
            if (secondPackUri == null)
                return 1;

            Check.PackUriIsValid(firstPackUri);
            Check.PackUriIsValid(secondPackUri);

            // FIXME: What exactly is compared. Lets assume originalstring
            return firstPackUri.OriginalString.CompareTo(secondPackUri.OriginalString);
        }

        internal void UriHitHandler(int node, Uri uri)
        {
            if (_uniqueUriRef != null)
            {
                if (_uniqueUriRef.Contains(uri))
                {
                    if ((int)_uniqueUriRef[uri] != node)
                    {
                        throw new FileFormatException(SR.Get(SRID.XpsValidatingLoaderDuplicateReference));
                    }
                }
                else
                {
                    _uniqueUriRef.Add(uri, node);
                }
            }
            Hashtable validResources = _validResources.Peek();

            if (validResources != null)
            {
                if (!validResources.ContainsKey(uri))
                {
                    // The hashtable is case sensitive, packuris are not, so if we do not find in hashtable,
                    // do true comparison and add when found for next time...
                    bool found = false;
                    foreach (Uri resUri in validResources.Keys)
                    {
                        if (PackUriHelper.ComparePackUri(resUri, uri) == 0)
                        {
                            validResources.Add(uri, validResources[resUri]);
                            found = true;
                            break;
                        }
                    }

                    if (!found)
                    {
                        throw new FileFormatException(SR.Get(SRID.XpsValidatingLoaderUnlistedResource));
                    }
                }
                if (!(bool)validResources[uri])
                {
                    throw new FileFormatException(SR.Get(SRID.XpsValidatingLoaderUnsupportedMimeType));
                }
            }
        }