DeltaZip.ArchiveWriter.AddFile C# (CSharp) Method

        public void AddFile(string root, string filename, Reference reference)
        {
            string fullFilename = Path.Combine(root, filename);
            using (FileStream fileStreamIn = new FileStream(fullFilename, FileMode.Open, FileAccess.Read, FileShare.Read, Settings.FileStreamBufferSize, true)) {
                stats.Status = "Compressing " + filename;
                stats.Progress = 0;

                BufferName = filename;
                BufferNameSuffix = 0;
                BufferNameForceAppendSuffix = false;

                SHA1CryptoServiceProvider sha1Provider = new SHA1CryptoServiceProvider();

                // Store
                List<int> hashIndices = new List<int>();
                long offset = 0;
                foreach (Block block in Splitter.Split(fileStreamIn, sha1Provider, false)) {
                    if (stats.Canceled) return;

                    Hash hash = Hash.Compute(block);

                    HashSource referenceHash;
                    string     referenceHashPath;

                    int hashIndex;
                    if (hashesLookup.TryGetValue(hash, out hashIndex)) {
                        // Internal reference
                        stats.SavedByInternalDelta += block.Length;
                        BufferNameForceAppendSuffix = true;
                    } else if (reference != null && reference.TryFindHash(hash, out referenceHash, out referenceHashPath)) {
                        // Reference to existing archive
                        stats.SavedByExternalDelta += block.Length;
                        BufferNameForceAppendSuffix = true;
                        // Copy the hash to local array
                        referenceHash.Path = this.AddString(referenceHashPath);
                        hashes.Add(referenceHash);
                        hashIndex = hashes.Count - 1;
                        hashesLookup[hash] = hashIndex;
                    } else {
                        // Store the data locally
                        hashIndex = WriteToBuffer(hash, block);
                        hashesLookup[hash] = hashIndex;
                    }
                    hashIndices.Add(hashIndex);

                    offset += block.Length;

                    stats.Progress = (float)offset / (float)fileStreamIn.Length;
                };
                if (offset != fileStreamIn.Length)
                    throw new Exception("Internal consistency error");

                FlushBuffer(true);

                FileInfo fileInfo = new FileInfo(fullFilename);

                File file = new File() {
                    Name = filename,
                    Size = fileInfo.Length,
                    Hash = sha1Provider.Hash,
                    Created = fileInfo.CreationTime,
                    Modified = fileInfo.LastWriteTime,
                    Attributes = fileInfo.Attributes & ~Settings.IgnoreAttributes,
                    HashIndices = hashIndices
                };
                files.Add(file);
            }
        }