PyBytes (buffer) .extend method needs to accept any iterable of ints

[gpshead]

BPO	1283
Nosy	@gpshead, @avassalotti
Files	byte_extend.patch byte_extend-2.patch byte_extend-3.patch byte_extend-4.patch byte_extend-5.patch

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = 'https://github.com/avassalotti'
closed_at = <Date 2007-12-04.05:51:36.612>
created_at = <Date 2007-10-16.00:31:50.311>
labels = ['interpreter-core', 'type-feature']
title = 'PyBytes (buffer) .extend method needs to accept any iterable of ints'
updated_at = <Date 2008-01-06.22:29:45.542>
user = 'https://github.com/gpshead'

bugs.python.org fields:

activity = <Date 2008-01-06.22:29:45.542>
actor = 'admin'
assignee = 'alexandre.vassalotti'
closed = True
closed_date = <Date 2007-12-04.05:51:36.612>
closer = 'alexandre.vassalotti'
components = ['Interpreter Core']
creation = <Date 2007-10-16.00:31:50.311>
creator = 'gregory.p.smith'
dependencies = []
files = ['8847', '8848', '8849', '8856', '8857']
hgrepos = []
issue_num = 1283
keywords = ['patch']
message_count = 9.0
messages = ['56478', '58072', '58073', '58074', '58106', '58107', '58108', '58109', '58177']
nosy_count = 2.0
nosy_names = ['gregory.p.smith', 'alexandre.vassalotti']
pr_nums = []
priority = 'low'
resolution = 'accepted'
stage = None
status = 'closed'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue1283'
versions = ['Python 3.0']

[gpshead]

The PyBytes (PEP-3137 buffer) .extend() method currently only accepts as
input something supporting the PEP-3118 buffer API. It also needs to
accept an iterable of ints in the 0..255 range.

[avassalotti]

Here a patch that adds support for any iterable (or sequence) of
integers to bytearray.extend().

[avassalotti]

Made 2 minor enhancements to the patch:
+ Added the proper type-cast to PyMem_Realloc call.
+ Changed (len >> 1) to (len >> 1) + 1, just to be sure that the
buffer doesn't overflow if __length_hint__ return 0 or 1 erroneously.

[avassalotti]

There is a reference leak in my previous patches. So, I updated (again)
the patch. There is still another possible leak if the PyMem_Realloc
return NULL (i.e., the system is out of memory), but I don't think it
worth fixing.

[avassalotti]

Here yet another revision of the patch. This one makes
bytearray.extend() try to determine the length of its argument a bit
more aggressively -- i.e., also uses PyObject_Length().

[gpshead]

"There is still another possible leak if the PyMem_Realloc
return NULL (i.e., the system is out of memory), but I don't think it
worth fixing."

Do it. It looks easy: a Py_DECREF(it) before the return PyErr_NoMemory().

[avassalotti]

Done. Is there any other issue with the patch?

[gpshead]

reading 5.patch over...

Any particular reason for using buf_size = 32 when the length isn't
known up front? add a comment saying why (or that its just a magic
guess). anyways it sounds like a fine starting value. picking
anything "better" would require profiling.

perhaps use a list comprehension instead of map() in the unit test?
either works, its a style thing.

(int(x) for x in orig*50) [int(x) for x in orig*50]

also the uses of 5 and -5 in that test could be written using
len(orig) instead of 5.

add another assertRaises that tests to make sure a list with -1 in it
raises a ValueError.

While I dislike that this code makes a temporary copy of the data
first, doing otherwise is more complicated so the simplicity of this
one wins. Leave that optimization for later. Your code looks good.

-gps

On 12/2/07, Alexandre Vassalotti <report@bugs.python.org> wrote:

Alexandre Vassalotti added the comment:

Done. Is there any other issue with the patch?

Added file: http://bugs.python.org/file8857/byte_extend-5.patch

---

Tracker <report@bugs.python.org>
<http://bugs.python.org/issue1283\>

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[avassalotti]

Thank you Gregory for the review!

Committed to r59314.