uproot.MemmapSource — Uproot documentation

# uproot.MemmapSource

Defined in uproot.source.file on line 91.

Inheritance order:
uproot.source.chunk.Source

class uproot.source.file.MemmapSource(file_path: str, **options)
  Parameters:

    - file_path (str) – The filesystem path of the file to open.

    - options – Must include `"num_fallback_workers"`.

  A uproot.source.chunk.Source that manages one memory-mapped file.

## file

MemmapSource.file

  The `numpy.memmap` array/file.

## fallback

MemmapSource.fallback

  If None, the file opened successfully and no fallback is needed.

  Otherwise, this is a uproot.MultithreadedFileSource to which all requests are forwarded.

## chunk

Inherited from uproot.source.chunk.Source.

MemmapSource.chunk(start: int, stop: int) → Chunk
  Parameters:

    - start (int) – Seek position of the first byte to include.

    - stop (int) – Seek position of the first byte to exclude (one greater than the last byte to include).

  Request a byte range of data from the file as a uproot.source.chunk.Chunk.

## chunks

Inherited from uproot.source.chunk.Source.

MemmapSource.chunks(ranges: list[int, int], notifications: Queue) → list[Chunk]
  Parameters:

    - ranges (list of (int, int) 2-tuples) – Intervals to fetch as (start, stop) pairs in a single request, if possible.

    - notifications (`queue.Queue`) – Indicator of completed chunks. After each gets filled, it is `put` on the queue; a listener should `get` from this queue `len(ranges)` times.

  Request a set of byte ranges from the file.

  This method has two outputs:

  - The method returns a list of unfilled uproot.source.chunk.Chunk objects, which get filled in a background thread. If you try to read data from an unfilled chunk, it will wait until it is filled.

  - The method also puts the same uproot.source.chunk.Chunk objects onto the `notifications` queue as soon as they are filled.

  Reading data from chunks on the queue can be more efficient than reading them from the returned list. The total reading time is the same, but work on the filled chunks can be better parallelized if it is triggered by already-filled chunks, rather than waiting for chunks to be filled.

## file_path

Inherited from uproot.source.chunk.Source.

MemmapSource.file_path

  A path to the file (or URL).

## num_bytes

Inherited from uproot.source.chunk.Source.

MemmapSource.num_bytes

## num_requests

Inherited from uproot.source.chunk.Source.

MemmapSource.num_requests

  The number of requests that have been made (performance counter).

## num_requested_chunks

Inherited from uproot.source.chunk.Source.

MemmapSource.num_requested_chunks

  The number of uproot.source.chunk.Chunk objects that have been requested (performance counter).

## num_requested_bytes

Inherited from uproot.source.chunk.Source.

MemmapSource.num_requested_bytes

  The number of bytes that have been requested (performance counter).

## performance_counters

Inherited from uproot.source.chunk.Source.

MemmapSource.performance_counters

## close

Inherited from uproot.source.chunk.Source.

MemmapSource.close()

  Manually closes the file(s) and stops any running threads.

## closed

Inherited from uproot.source.chunk.Source.

MemmapSource.closed