Lucene.Net.Store.CompoundFileDirectory.ReadEntries C# (CSharp) Method

ReadEntries() private static method

Helper method that reads CFS entries from an input stream
private static ReadEntries ( IndexInputSlicer handle, Lucene.Net.Store.Directory dir, string name ) : FileEntry>.IDictionary
handle IndexInputSlicer
dir Lucene.Net.Store.Directory
name string
return FileEntry>.IDictionary
        private static IDictionary<string, FileEntry> ReadEntries(IndexInputSlicer handle, Directory dir, string name)
        {
            System.IO.IOException priorE = null;
            IndexInput stream = null;
            ChecksumIndexInput entriesStream = null;
            // read the first VInt. If it is negative, it's the version number
            // otherwise it's the count (pre-3.1 indexes)
            try
            {
                IDictionary<string, FileEntry> mapping;
                stream = handle.OpenFullSlice();
                int firstInt = stream.ReadVInt();
                // impossible for 3.0 to have 63 files in a .cfs, CFS writer was not visible
                // and separate norms/etc are outside of cfs.
                if (firstInt == CODEC_MAGIC_BYTE1)
                {
                    sbyte secondByte = (sbyte)stream.ReadByte();
                    sbyte thirdByte = (sbyte)stream.ReadByte();
                    sbyte fourthByte = (sbyte)stream.ReadByte();
                    if (secondByte != CODEC_MAGIC_BYTE2 || thirdByte != CODEC_MAGIC_BYTE3 || fourthByte != CODEC_MAGIC_BYTE4)
                    {
                        throw new CorruptIndexException("Illegal/impossible header for CFS file: " + secondByte + "," + thirdByte + "," + fourthByte);
                    }
                    int version = CodecUtil.CheckHeaderNoMagic(stream, CompoundFileWriter.DATA_CODEC, CompoundFileWriter.VERSION_START, CompoundFileWriter.VERSION_CURRENT);
                    string entriesFileName = IndexFileNames.SegmentFileName(IndexFileNames.StripExtension(name), "", IndexFileNames.COMPOUND_FILE_ENTRIES_EXTENSION);
                    entriesStream = dir.OpenChecksumInput(entriesFileName, IOContext.READONCE);
                    CodecUtil.CheckHeader(entriesStream, CompoundFileWriter.ENTRY_CODEC, CompoundFileWriter.VERSION_START, CompoundFileWriter.VERSION_CURRENT);
                    int numEntries = entriesStream.ReadVInt();
                    mapping = new Dictionary<string, FileEntry>(numEntries);
                    for (int i = 0; i < numEntries; i++)
                    {
                        FileEntry fileEntry = new FileEntry();
                        string id = entriesStream.ReadString();

                        //If the key was already present
                        if (mapping.ContainsKey(id))
                        {
                            throw new CorruptIndexException("Duplicate cfs entry id=" + id + " in CFS: " + entriesStream);
                        }
                        else
                        {
                            mapping[id] = fileEntry;
                        }
                        fileEntry.Offset = entriesStream.ReadLong();
                        fileEntry.Length = entriesStream.ReadLong();
                    }
                    if (version >= CompoundFileWriter.VERSION_CHECKSUM)
                    {
                        CodecUtil.CheckFooter(entriesStream);
                    }
                    else
                    {
                        CodecUtil.CheckEOF(entriesStream);
                    }
                }
                else
                {
                    // TODO remove once 3.x is not supported anymore
                    mapping = ReadLegacyEntries(stream, firstInt);
                }
                return mapping;
            }
            catch (System.IO.IOException ioe)
            {
                priorE = ioe;
            }
            finally
            {
                IOUtils.CloseWhileHandlingException(priorE, stream, entriesStream);
            }
            // this is needed until Java 7's real try-with-resources:
            throw new InvalidOperationException("impossible to get here");
        }