I should add that I'm using CPython 3 on a Mac, happy to receive CPython 3
UNIX-specific advice. - Cameron
On 06Aug2018 09:28, Cameron Simpson <c...@cskk.id.au> wrote:
I'm tinkering with a module which scans video files. The MP4 parser
has a `discard_data` parameter which tells certain parts of the parser
to discard some of the scanned data, particularly the MDAT box parse
because I don't normally want to blow the machine's RAM on a huge
video stream - I'm normally parsing out the semantic info such as
metadata.
However, I would _like_ to keep it available in a frugal fashion if I
can, and it seems to me that the mmap module is ideal: map the file
into memory, use the file itself as the backing store, and return
views of the mmap.
But slicing a mmap object returns a bytes, which I _imagine_ to be a
copy of the file data instead of a view into the mapping (because
bytes are supposed to be immutable, and in theory some other actor
might change the file even though I myself have it mapped read only).
It seems obvious to me that a method returning a memoryview of the
mapped file would be very handy here: no data copies at all, and not
even any I/O unless the data are accessed. But I see no such method in
the documentation.
Does anyone have any insight here?
Cheers,
Cameron Simpson <c...@cskk.id.au>
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