[issue26379] zlib decompress as_bytearray flag

[Joe Jevnik]

New submission from Joe Jevnik:

Adds a keyword only flag to zlib.decompress and zlib.Decompress.decompress which marks that the return type should be a bytearray instead of bytes.

The use case for this is reading compressed data into a mutable array to do further operations without requiring that the user copy the data first. Often, if a user is choosing to compress the data there might be a real cost to copying the uncompressed bytes into a mutable buffer.

The impetus for this change comes from a patch for Pandas (https://github.com/pydata/pandas/pull/12359). I have also worked on a similar feature for blosc, another popular compression library for python (https://github.com/Blosc/python-blosc/pull/107).

My hope is to fix the hacky solution presented in the pandas patch by supporting this feature directly in the compression libraries.

As a side note: this is my first time using the argument clinic and I love it. It was so simple to add this argument, thank you very much for developing such an amazing tool!

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components: Extension Modules
files: zlib.patch
keywords: patch
messages: 260424
nosy: llllllllll
priority: normal
severity: normal
status: open
title: zlib decompress as_bytearray flag
type: enhancement
versions: Python 3.6
Added file: http://bugs.python.org/file41944/zlib.patch

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<http://bugs.python.org/issue26379>
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