private InputStream ReadStream(int streamIndex, MemoryMappedFile memoryMappedFile, long offset, long size)
{
int chunkSize = _settings.ChunkSize;
int chunkIndex = 0;
InputStream inputStream = new InputStream(streamIndex);
while (size > 0)
{
if (size < chunkSize)
{
chunkSize = (int)size;
}
IStreamChunk inputStreamChunk = new MemoryMappedFileChunk(chunkIndex, memoryMappedFile, offset, chunkSize);
inputStream.Chunks.Add(inputStreamChunk);
chunkIndex++;
offset += chunkSize;
size -= chunkSize;
}
return(inputStream);
}
public IEnumerable <InputStream> Read(string fileName, CancellationToken cancellationToken)
{
if (string.IsNullOrEmpty(fileName))
{
throw new ArgumentException("Input file name must be non-empty");
}
List <InputStream> inputStreams = new List <InputStream>();
FileInfo fileInfo = new FileInfo(fileName);
long size = fileInfo.Length;
int chunkSize = _settings.ChunkSize;
if (size < chunkSize)
{
InputStream inputStream = new InputStream(0);
IStreamChunk inputStreamChunk = new StreamChunk(0, fileInfo.Open(FileMode.Open));
inputStream.Chunks.Add(inputStreamChunk);
inputStreams.Add(inputStream);
}
else
{
long offset = 0;
long streamsCount = _settings.StreamsCount;
long chunksCount = size / (streamsCount * chunkSize);
if (chunksCount == 0)
{
throw new CompressionException("Streams count or chunk size are too big");
}
int chunkIndex = 0;
InputStream inputStream = new InputStream(0);
MemoryMappedFile memoryMappedFile = MemoryMappedFile.CreateFromFile(fileName);
while (size > 0)
{
if (cancellationToken.IsCancellationRequested)
{
break;
}
if (size < chunkSize)
{
chunkSize = (int)size;
}
IStreamChunk inputStreamChunk = new MemoryMappedFileChunk(chunkIndex, memoryMappedFile, offset, chunkSize);
inputStream.Chunks.Add(inputStreamChunk);
chunkIndex++;
offset += chunkSize;
size -= chunkSize;
if (chunkIndex > chunksCount &&
size > chunkSize)
{
chunkIndex = 0;
inputStreams.Add(inputStream);
inputStream = new InputStream(inputStreams.Count);
}
}
inputStreams.Add(inputStream);
}
return(inputStreams);
}
