Python buffer objects can have negative strides.
diff --git a/docs/advanced/pycpp/numpy.rst b/docs/advanced/pycpp/numpy.rst
index 6bcc467..42f376c 100644
--- a/docs/advanced/pycpp/numpy.rst
+++ b/docs/advanced/pycpp/numpy.rst
@@ -41,8 +41,8 @@
py::format_descriptor<float>::format(), /* Python struct-style format descriptor */
2, /* Number of dimensions */
{ m.rows(), m.cols() }, /* Buffer dimensions */
- { sizeof(float) * m.rows(), /* Strides (in bytes) for each index */
- sizeof(float) }
+ { (ssize_t)( sizeof(float) * m.rows() ),/* Strides (in bytes) for each index */
+ (ssize_t)( sizeof(float) ) }
);
});
@@ -61,7 +61,7 @@
std::string format;
int ndim;
std::vector<size_t> shape;
- std::vector<size_t> strides;
+ std::vector<ssize_t> strides;
};
To create a C++ function that can take a Python buffer object as an argument,
@@ -121,8 +121,8 @@
{ (size_t) m.rows(),
(size_t) m.cols() },
/* Strides (in bytes) for each index */
- { sizeof(Scalar) * (rowMajor ? m.cols() : 1),
- sizeof(Scalar) * (rowMajor ? 1 : m.rows()) }
+ { (ssize_t)( sizeof(Scalar) * (rowMajor ? m.cols() : 1) ),
+ (ssize_t)( sizeof(Scalar) * (rowMajor ? 1 : m.rows()) ) }
);
})
diff --git a/include/pybind11/numpy.h b/include/pybind11/numpy.h
index ba9402b..f86df9c 100644
--- a/include/pybind11/numpy.h
+++ b/include/pybind11/numpy.h
@@ -265,14 +265,14 @@
const unsigned char *data_;
// Storing the shape & strides in local variables (i.e. these arrays) allows the compiler to
// make large performance gains on big, nested loops, but requires compile-time dimensions
- conditional_t<Dynamic, const size_t *, std::array<size_t, (size_t) Dims>>
- shape_, strides_;
+ conditional_t<Dynamic, const size_t *, std::array<size_t, (size_t) Dims>> shape_;
+ conditional_t<Dynamic, const ssize_t *, std::array<ssize_t, (size_t) Dims>> strides_;
const size_t dims_;
friend class pybind11::array;
// Constructor for compile-time dimensions:
template <bool Dyn = Dynamic>
- unchecked_reference(const void *data, const size_t *shape, const size_t *strides, enable_if_t<!Dyn, size_t>)
+ unchecked_reference(const void *data, const size_t *shape, const ssize_t *strides, enable_if_t<!Dyn, size_t>)
: data_{reinterpret_cast<const unsigned char *>(data)}, dims_{Dims} {
for (size_t i = 0; i < dims_; i++) {
shape_[i] = shape[i];
@@ -281,7 +281,7 @@
}
// Constructor for runtime dimensions:
template <bool Dyn = Dynamic>
- unchecked_reference(const void *data, const size_t *shape, const size_t *strides, enable_if_t<Dyn, size_t> dims)
+ unchecked_reference(const void *data, const size_t *shape, const ssize_t *strides, enable_if_t<Dyn, size_t> dims)
: data_{reinterpret_cast<const unsigned char *>(data)}, shape_{shape}, strides_{strides}, dims_{dims} {}
public:
@@ -573,12 +573,12 @@
}
/// Strides of the array
- const size_t* strides() const {
- return reinterpret_cast<const size_t *>(detail::array_proxy(m_ptr)->strides);
+ const ssize_t* strides() const {
+ return reinterpret_cast<const ssize_t *>(detail::array_proxy(m_ptr)->strides);
}
/// Stride along a given axis
- size_t strides(size_t dim) const {
+ ssize_t strides(size_t dim) const {
if (dim >= ndim())
fail_dim_check(dim, "invalid axis");
return strides()[dim];
@@ -702,9 +702,9 @@
throw std::domain_error("array is not writeable");
}
- static std::vector<Py_intptr_t> default_strides(const std::vector<Py_intptr_t>& shape, size_t itemsize) {
+ static std::vector<ssize_t> default_strides(const std::vector<size_t>& shape, size_t itemsize) {
auto ndim = shape.size();
- std::vector<Py_intptr_t> strides(ndim);
+ std::vector<ssize_t> strides(ndim);
if (ndim) {
std::fill(strides.begin(), strides.end(), itemsize);
for (size_t i = 0; i < ndim - 1; i++)
@@ -1133,7 +1133,7 @@
class common_iterator {
public:
- using container_type = std::vector<size_t>;
+ using container_type = std::vector<ssize_t>;
using value_type = container_type::value_type;
using size_type = container_type::size_type;
@@ -1175,7 +1175,7 @@
for (size_t i = 0; i < shape.size(); ++i)
m_shape[i] = static_cast<container_type::value_type>(shape[i]);
- container_type strides(shape.size());
+ std::vector<ssize_t> strides(shape.size());
for (size_t i = 0; i < N; ++i)
init_common_iterator(buffers[i], shape, m_common_iterator[i], strides);
}
@@ -1203,7 +1203,7 @@
void init_common_iterator(const buffer_info &buffer,
const std::vector<size_t> &shape,
- common_iter &iterator, container_type &strides) {
+ common_iter &iterator, std::vector<ssize_t> &strides) {
auto buffer_shape_iter = buffer.shape.rbegin();
auto buffer_strides_iter = buffer.strides.rbegin();
auto shape_iter = shape.rbegin();
@@ -1211,7 +1211,7 @@
while (buffer_shape_iter != buffer.shape.rend()) {
if (*shape_iter == *buffer_shape_iter)
- *strides_iter = static_cast<size_t>(*buffer_strides_iter);
+ *strides_iter = *buffer_strides_iter;
else
*strides_iter = 0;
@@ -1283,10 +1283,11 @@
// Check for C contiguity (but only if previous inputs were also C contiguous)
if (trivial_broadcast_c) {
- size_t expect_stride = buffers[i].itemsize;
+ ssize_t expect_stride = static_cast<ssize_t>(buffers[i].itemsize);
auto end = buffers[i].shape.crend();
- for (auto shape_iter = buffers[i].shape.crbegin(), stride_iter = buffers[i].strides.crbegin();
- trivial_broadcast_c && shape_iter != end; ++shape_iter, ++stride_iter) {
+ auto shape_iter = buffers[i].shape.crbegin();
+ auto stride_iter = buffers[i].strides.crbegin();
+ for (; trivial_broadcast_c && shape_iter != end; ++shape_iter, ++stride_iter) {
if (expect_stride == *stride_iter)
expect_stride *= *shape_iter;
else
@@ -1296,10 +1297,11 @@
// Check for Fortran contiguity (if previous inputs were also F contiguous)
if (trivial_broadcast_f) {
- size_t expect_stride = buffers[i].itemsize;
+ ssize_t expect_stride = static_cast<ssize_t>(buffers[i].itemsize);
auto end = buffers[i].shape.cend();
- for (auto shape_iter = buffers[i].shape.cbegin(), stride_iter = buffers[i].strides.cbegin();
- trivial_broadcast_f && shape_iter != end; ++shape_iter, ++stride_iter) {
+ auto shape_iter = buffers[i].shape.cbegin();
+ auto stride_iter = buffers[i].strides.cbegin();
+ for (; trivial_broadcast_f && shape_iter != end; ++shape_iter, ++stride_iter) {
if (expect_stride == *stride_iter)
expect_stride *= *shape_iter;
else
@@ -1336,20 +1338,20 @@
auto trivial = broadcast(buffers, ndim, shape);
size_t size = 1;
- std::vector<size_t> strides(ndim);
+ std::vector<ssize_t> strides(ndim);
if (ndim > 0) {
if (trivial == broadcast_trivial::f_trivial) {
- strides[0] = sizeof(Return);
+ strides[0] = static_cast<ssize_t>(sizeof(Return));
for (size_t i = 1; i < ndim; ++i) {
- strides[i] = strides[i - 1] * shape[i - 1];
+ strides[i] = strides[i - 1] * static_cast<ssize_t>(shape[i - 1]);
size *= shape[i - 1];
}
size *= shape[ndim - 1];
}
else {
- strides[ndim-1] = sizeof(Return);
+ strides[ndim-1] = static_cast<ssize_t>(sizeof(Return));
for (size_t i = ndim - 1; i > 0; --i) {
- strides[i - 1] = strides[i] * shape[i];
+ strides[i - 1] = strides[i] * static_cast<ssize_t>(shape[i]);
size *= shape[i];
}
size *= shape[0];
diff --git a/tests/test_buffers.cpp b/tests/test_buffers.cpp
index 057250d..d533bd3 100644
--- a/tests/test_buffers.cpp
+++ b/tests/test_buffers.cpp
@@ -109,8 +109,8 @@
py::format_descriptor<float>::format(), /* Python struct-style format descriptor */
2, /* Number of dimensions */
{ m.rows(), m.cols() }, /* Buffer dimensions */
- { sizeof(float) * m.rows(), /* Strides (in bytes) for each index */
- sizeof(float) }
+ { static_cast<ssize_t>(sizeof(float) * m.rows()), /* Strides (in bytes) for each index */
+ static_cast<ssize_t>(sizeof(float)) }
);
})
;
diff --git a/tests/test_numpy_array.cpp b/tests/test_numpy_array.cpp
index 85c185f..e431e09 100644
--- a/tests/test_numpy_array.cpp
+++ b/tests/test_numpy_array.cpp
@@ -13,6 +13,7 @@
#include <pybind11/stl.h>
#include <cstdint>
+#include <vector>
using arr = py::array;
using arr_t = py::array_t<uint16_t, 0>;
@@ -294,4 +295,4 @@
std::fill(a.mutable_data(), a.mutable_data() + a.size(), 42.);
return a;
});
-});
\ No newline at end of file
+});
diff --git a/tests/test_numpy_array.py b/tests/test_numpy_array.py
index 10af748..90f9b80 100644
--- a/tests/test_numpy_array.py
+++ b/tests/test_numpy_array.py
@@ -203,6 +203,10 @@
a2 = wrap(a1d)
assert_references(a1d, a2, a1)
+ a1m = a1[::-1, ::-1, ::-1]
+ a2 = wrap(a1m)
+ assert_references(a1m, a2, a1)
+
def test_numpy_view(capture):
from pybind11_tests.array import ArrayClass
diff --git a/tests/test_numpy_dtypes.cpp b/tests/test_numpy_dtypes.cpp
index 1f6c857..4fc797c 100644
--- a/tests/test_numpy_dtypes.cpp
+++ b/tests/test_numpy_dtypes.cpp
@@ -226,7 +226,7 @@
std::vector<int32_t> data { 1, 2, 3, 4, 5, 6 };
std::vector<size_t> shape { 3, 2 };
- std::vector<size_t> strides { 8, 4 };
+ std::vector<ssize_t> strides { 8, 4 };
auto ptr = data.data();
auto vptr = (void *) ptr;