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Commit 13ab570
Remove redundant check from arraymodule b_getitem (GH-14676)
The `arraymodule`'s `b_getitem` function returns a `PyLong` converted
from `arrayobject`'s array, by dereferencing a pointer to `char`.
When the `char` type is `signed char`, the `if (x >= 128) x -= 256;` comparison/code is redundant because a `signed char` will have a value of `[-128, 127]` and so `x` will never be greater or equal than 128.
This check was indeed needed for situations where a given compiler would assume `char` being `unsigned char` which would make `x` in `[0, 256]` range.
However, the check can be removed if we cast the `ob_item` into a signed char pointer (`signed char*`) instead of `char*`.
This PR/commit introduces this change.1 parent 4737265 commit 13ab570
1 file changed
Lines changed: 1 addition & 3 deletions
| Original file line number | Diff line number | Diff line change | |
|---|---|---|---|
@@ -185,9 +185,7 @@ in bounds; that's the responsibility of the caller. | |||
| 185 | 185 | static PyObject * | |
| 186 | 186 | b_getitem(arrayobject *ap, Py_ssize_t i) | |
| 187 | 187 | { | |
| 188 | - long x = ((char *)ap->ob_item)[i]; | ||
| 189 | - if (x >= 128) | ||
| 190 | - x -= 256; | ||
| 188 | + long x = ((signed char *)ap->ob_item)[i]; | ||
| 191 | 189 | return PyLong_FromLong(x); | |
| 192 | 190 | } | |
| 193 | 191 | ||
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