GUPPIFileWriter

class baseband.guppi.base.GUPPIFileWriter(fh_raw)

Bases: FileBase

Simple writer/mapper for GUPPI files.

Adds write_frame and memmap_frame methods to the binary file wrapper. The latter allows one to encode data in pieces, writing to disk as needed.

Attributes Summary

fh_raw

Methods Summary

close()
memmap_frame([header])	Get frame by writing the header to disk and mapping its payload.
temporary_offset([offset, whence])	Context manager for temporarily seeking to another file position.
write_frame(data[, header])	Write a single frame (header plus payload).

Attributes Documentation

fh_raw = None

Methods Documentation

close()

memmap_frame(header=None, **kwargs)

Get frame by writing the header to disk and mapping its payload.

The header is written to disk immediately, but the payload is mapped, so that it can be filled in pieces, by setting slices of the frame.

Parameters:

headerGUPPIHeader

Written to disk immediately. Can instead give keyword arguments to construct a header.

**kwargs

If header is not given, these are used to initialize one.

Returns:

frame: GUPPIFrame

By assigning slices to data, the payload can be encoded piecewise.

temporary_offset(offset=None, whence=0)

Context manager for temporarily seeking to another file position.

To be used as part of a with statement:

with fh_raw.temporary_offset() [as fh_raw]:
    with-block

On exiting the with-block, the file pointer is moved back to its original position. As a convenience, one can pass on the offset to seek to when entering the context manager. Parameters are as for io.IOBase.seek().

write_frame(data, header=None, **kwargs)

Write a single frame (header plus payload).

Parameters:

datandarray or GUPPIFrame

If an array, a header should be given, which will be used to get the information needed to encode the array, and to construct the GUPPI frame.

headerGUPPIHeader

Can instead give keyword arguments to construct a header. Ignored if data is a GUPPIFrame instance.

**kwargs

If header is not given, these are used to initialize one.