[New-bugs-announce] [issue19577] memoryview bind (the opposite of release)

[mpb]

New submission from mpb:

I'm writing Python code to parse binary (byte oriented) data.

I am (at least somewhat) aware of the performance implications of various approaches to doing the parsing.  With performance in mind, I would like to avoid unnecessary creation/destruction/copying of memory/objects.

An example:

Let's say I am parsing b'0123456789'.
I want to extract and return the substring b'234'.

Now let's say I do this with memoryviews, to avoid unnecessary creation and copying of memory.

m0 = memoryview (b'0123456789')
m1 = m0[2:5]    # m1 == b'234'

Let's say I do this 1000 times.  Each time I use readinto to load the next data into m0.  So I can create m0 only once and reuse it.

But if the relative position of m1 inside m0 changes with each parse, then I need to create a new m1 for each parse.

In the context of the above example, I think it might be nice if I could rebind an existing memoryview to a new object.  For example:

m0 = memoryview (b'0123456789')
m1.bind (m0, 2, 5)    # m1 == b'234'

Is this an idea worth considering?

(Possibly related: Issue 9789, 9757, 3506; PEP 3118)

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messages: 202806
nosy: mpb
priority: normal
severity: normal
status: open
title: memoryview bind (the opposite of release)
type: enhancement
versions: Python 3.5

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue19577>
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