public static FileSection ReadFileProperty(this Stream stream, byte[] buf, UmdFile file)
        {
            //#开头
            int start = stream.ReadByte();

            if (start != '#')
            {
                stream.Position = stream.Position - 1;
                return(null);
            }
            //两个字节,表示类别
            stream.ReadLength(buf, 2);
            int type = BitConverter.ToInt16(buf, 0);

            if (!IsFileProperty(type))
            {
                stream.Position = stream.Position - 3;
                return(null);
            }
            //一个无意义字节
            stream.ReadByte();
            //一个长度的字节
            int len = stream.ReadByte() - 5;

            stream.ReadLength(buf, len);
            var typeEnum = (MetaDataEnum)type;

            switch (typeEnum)
            {
            case MetaDataEnum.FileStart:
                return(null);

            case MetaDataEnum.Title:
                var title = new FileTitleSection
                {
                    Title = Encoding.Unicode.GetString(buf, 0, len)
                };
                file.Title = title;
                return(title);

            case MetaDataEnum.Author:
                var author = new AuthorSection
                {
                    Author = Encoding.Unicode.GetString(buf, 0, len)
                };
                file.Author = author;
                return(author);

            case MetaDataEnum.Year:
                var year = new YearSection
                {
                    Year = Encoding.Unicode.GetString(buf, 0, len)
                };
                if (file.PublishDate == null)
                {
                    file.PublishDate = new PublishDateSection();
                }
                file.PublishDate.Year = year;
                return(year);

            case MetaDataEnum.Month:
                var month = new MonthSection
                {
                    Month = Encoding.Unicode.GetString(buf, 0, len)
                };
                if (file.PublishDate == null)
                {
                    file.PublishDate = new PublishDateSection();
                }
                file.PublishDate.Month = month;
                return(month);

            case MetaDataEnum.Day:
                var day = new DaySection
                {
                    Day = Encoding.Unicode.GetString(buf, 0, len)
                };
                if (file.PublishDate == null)
                {
                    file.PublishDate = new PublishDateSection();
                }
                file.PublishDate.Day = day;
                return(day);

            case MetaDataEnum.NovelType:
                var novelType = new NovelTypeSection
                {
                    NovelType = Encoding.Unicode.GetString(buf, 0, len)
                };
                file.NovelType = novelType;
                return(novelType);

            case MetaDataEnum.Publisher:
                var publisher = new PublisherSection
                {
                    Publisher = Encoding.Unicode.GetString(buf, 0, len)
                };
                file.Publisher = publisher;
                return(publisher);

            case MetaDataEnum.Saler:
                var saler = new SalerSection
                {
                    Saler = Encoding.Unicode.GetString(buf, 0, len)
                };
                file.Saler = saler;
                return(saler);

            case MetaDataEnum.ContentLength:
                var contentLength = new ContentLengthSection
                {
                    ContentLength = BitConverter.ToInt32(buf, 0)
                };
                file.ContentLength = contentLength;
                return(contentLength);

            default:
                return(null);
            }
        }
        public UmdFile Parse(Stream stream)
        {
            var buf  = new byte[33 * 1024];
            var file = new UmdFile();

            //前四个字节区分文件类型
            stream.ReadLength(buf, 4);
            //然后是5个固定的字节
            stream.ReadLength(buf, 5);
            //下面一个字节指定文件类型
            var filetype = stream.ReadByte();

            if (filetype != 1)
            {
                throw new Exception("只能读取文件类型的umd文件");
            }
            //接下来2个随机数
            stream.ReadLength(buf, 2);
            //接下来读取文件属性02->ob
            FileSection p = null;

            do
            {
                p = stream.ReadFileProperty(buf, file);
            } while (p != null);
            //章节偏移量
            file.ChapterOffset = stream.ReadChapterOffset(buf);
            //章节标题
            file.ChapterTitle = stream.ReadChapterTitle(buf, file.ChapterOffset.ChapterOffset.Count);
            //正文
            file.Content = stream.ReadContent(buf);
            //封面
            file.Cover = stream.ReadCover(buf);
            //页面偏移
            PageOffsetItem pageoffsetItem = null;

            do
            {
                pageoffsetItem = stream.ReadPageOffsetItem(buf);

                if (file.PageOffset == null)
                {
                    file.PageOffset = new PageOffsetSection {
                        PageOffsetCollection = new List <PageOffsetItem>()
                    };
                }
                if (pageoffsetItem != null)
                {
                    file.PageOffset.PageOffsetCollection.Add(pageoffsetItem);
                }
            } while (pageoffsetItem != null);
            //文件结束 9个字节
            stream.ReadByte();
            var end = stream.ReadByte();

            if (end != 0x0c)
            {
                stream.ReadLength(buf, (int)(stream.Length - stream.Position));
                Console.WriteLine("文件大小对不上");
            }

            if (file.Content.Content == null)
            {
                file.Content.Content = new string[file.ChapterOffset.ChapterOffset.Count];
            }

            return(file);
        }