Optimize Endianness Handling in ctypes Module

[Harikrishna-Srinivasan]

Feature or enhancement

Proposal:

1. Global variable _OTHER_ENDIAN, in the _other_endian function to check for endianness but declared at the module level, leading to potential side effects.

Redundant Type Checks slows down recursion:

if hasattr(typ, _OTHER_ENDIAN):
if isinstance(typ, _array_type):
if issubclass(typ, (Structure, Union)):

Issue: Multiple checks on each call can be inefficient, especially if called frequently.

2. In the setattr method of the _swapped_meta class,

for desc in value:
    fields.append((name, _other_endian(typ)) + rest)

Issue: Always creates a new list, even when no modifications are needed, which adds overhead.

Has this already been discussed elsewhere?

This is a minor feature, which does not need previous discussion elsewhere

Links to previous discussion of this feature:

No response

Linked PRs

• gh-124351: Optimize Endianness Handling in ctypes Module #124355
• gh-124351: Optimize Endianness Handling in ctypes Module #124355 #124407
• gh-124351: Improve Clarity in Endianness Handling of ctypes Module #124410

[skirpichev]

Global variable _OTHER_ENDIAN, in the _other_endian function to check for endianness but declared at the module level, leading to potential side effects.

Why you think so, could you provide an example?

Always creates a new list, even when no modifications are needed, which adds overhead.

How you are suggesting to avoid this?

[picnixz]

Closing since the related PRs were closed and the change is cosmetic only (the constant is global but private).