Bloom.Publish.EpubMaker.GetIdOfFile C# (CSharp) Method

        private string GetIdOfFile(string item)
        {
            string id;
            if (_mapItemToId.TryGetValue(item, out id))
                return id;
            id = ToValidXmlId(Path.GetFileNameWithoutExtension(item));
            var idOriginal = id;
            for (int i = 1; _idsUsed.Contains(id.ToLowerInvariant()); i++)
            {
                // Somehow we made a clash
                id = idOriginal + i;
            }
            _idsUsed.Add(id.ToLowerInvariant());
            _mapItemToId[item] = id;

            return id;
        }