Created
March 3, 2017 23:58
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Take some malloc'd memory, stuff it into a NumPy ndarray so that, when this array is out of scope, the original memory is free'd.
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import numpy as np | |
cimport numpy as np | |
cdef extern from "numpy/arrayobject.h": | |
void PyArray_ENABLEFLAGS(np.ndarray arr, int flags) | |
object PyArray_SimpleNewFromData(int nd, np.npy_intp* dims, int typenum, void* data) | |
void _import_array() | |
cdef np.ndarray[np.int32_t, ndim=1, mode='c'] from_pointer_to_ndarray(np.npy_intp n_elements, | |
np.int32_t* values): | |
# THIS LINE IS CRITICAL: https://docs.scipy.org/doc/numpy/reference/c-api.array.html#c.import_array | |
_import_array() | |
cdef np.ndarray[np.int32_t, ndim=1, mode='c'] np_values; | |
np_values = np.PyArray_SimpleNewFromData(1, &n_elements, np.NPY_INT32, values) | |
# PyArray_ENABLEFLAGS is *critical* !!! | |
# It ensures that, when this ndarray goes out of scope, the underlying array's memory | |
# is free'd (aka our np.int32_t* community is free'd). | |
PyArray_ENABLEFLAGS(np_values, np.NPY_OWNDATA) | |
return np_values |
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