mcs/class/System.IO.Compression/SharpCompress/Common/Zip/SeekableZipFilePart.cs

   1 using System.IO;
   2 using SharpCompress.Common.Zip.Headers;
   3
   4 namespace SharpCompress.Common.Zip
   5 {
   6     internal class SeekableZipFilePart : ZipFilePart
   7     {
   8         private bool isLocalHeaderLoaded;
   9         private readonly SeekableZipHeaderFactory headerFactory;
  10
  11         internal SeekableZipFilePart(SeekableZipHeaderFactory headerFactory, DirectoryEntryHeader header, Stream stream)
  12             : base(header, stream)
  13         {
  14             this.headerFactory = headerFactory;
  15         }
  16
  17         internal override Stream GetCompressedStream()
  18         {
  19             if (!isLocalHeaderLoaded)
  20             {
  21                 LoadLocalHeader();
  22                 isLocalHeaderLoaded = true;
  23             }
  24             return base.GetCompressedStream();
  25         }
  26
  27         internal string Comment
  28         {
  29             get { return (Header as DirectoryEntryHeader).Comment; }
  30         }
  31
  32         private void LoadLocalHeader()
  33         {
  34             bool hasData = Header.HasData;
  35             Header = headerFactory.GetLocalHeader(BaseStream, Header as DirectoryEntryHeader);
  36             Header.HasData = hasData;
  37         }
  38
  39         protected override Stream CreateBaseStream()
  40         {
  41             BaseStream.Position = Header.DataStartPosition.Value;
  42             return BaseStream;
  43         }
  44     }
  45 }