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Issue #22445: PyBuffer_IsContiguous() now implements precise contiguity

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tests, compatible with NumPy's NPY_RELAXED_STRIDES_CHECKING compilation
flag.  Previously the function reported false negatives for corner cases.
This commit is contained in:
Stefan Krah 2015-02-01 14:53:54 +01:00
parent a5e1dbef14
commit 363af44a4a
4 changed files with 90 additions and 29 deletions
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49
Objects/abstract.c
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@ -367,16 +367,35 @@ _IsFortranContiguous(const Py_buffer *view)
Py_ssize_t sd, dim;
int i;
if (view->ndim == 0) return 1;
if (view->strides == NULL) return (view->ndim == 1);
/* 1) len = product(shape) * itemsize
2) itemsize > 0
3) len = 0 <==> exists i: shape[i] = 0 */
if (view->len == 0) return 1;
if (view->strides == NULL) { /* C-contiguous by definition */
/* Trivially F-contiguous */
if (view->ndim <= 1) return 1;
/* ndim > 1 implies shape != NULL */
assert(view->shape != NULL);
/* Effectively 1-d */
sd = 0;
for (i=0; i<view->ndim; i++) {
if (view->shape[i] > 1) sd += 1;
}
return sd <= 1;
}
/* strides != NULL implies both of these */
assert(view->ndim > 0);
assert(view->shape != NULL);
sd = view->itemsize;
if (view->ndim == 1) return (view->shape[0] == 1 ||
sd == view->strides[0]);
for (i=0; i<view->ndim; i++) {
dim = view->shape[i];
if (dim == 0) return 1;
if (view->strides[i] != sd) return 0;
if (dim > 1 && view->strides[i] != sd) {
return 0;
}
sd *= dim;
}
return 1;
@ -388,16 +407,22 @@ _IsCContiguous(const Py_buffer *view)
Py_ssize_t sd, dim;
int i;
if (view->ndim == 0) return 1;
if (view->strides == NULL) return 1;
/* 1) len = product(shape) * itemsize
2) itemsize > 0
3) len = 0 <==> exists i: shape[i] = 0 */
if (view->len == 0) return 1;
if (view->strides == NULL) return 1; /* C-contiguous by definition */
/* strides != NULL implies both of these */
assert(view->ndim > 0);
assert(view->shape != NULL);
sd = view->itemsize;
if (view->ndim == 1) return (view->shape[0] == 1 ||
sd == view->strides[0]);
for (i=view->ndim-1; i>=0; i--) {
dim = view->shape[i];
if (dim == 0) return 1;
if (view->strides[i] != sd) return 0;
if (dim > 1 && view->strides[i] != sd) {
return 0;
}
sd *= dim;
}
return 1;