ENH: Extern memory management to Cython (numpy#27630)

Add NumPy's memory management functionality to numpy.pxd so Cython users can leverage it.

Author: jakirkham

numpy/__init__.cython-30.pxd

@@ -757,6 +757,23 @@ cdef extern from "numpy/arrayobject.h":
     npy_intp PyArray_OverflowMultiplyList (npy_intp *, int)
     int PyArray_SetBaseObject(ndarray, base) except -1 # NOTE: steals a reference to base! Use "set_array_base()" instead.
 
+    # The memory handler functions require the NumPy 1.22 API
+    # and may require defining NPY_TARGET_VERSION
+    ctypedef struct PyDataMemAllocator:
+        void *ctx
+        void* (*malloc) (void *ctx, size_t size)
+        void* (*calloc) (void *ctx, size_t nelem, size_t elsize)
+        void* (*realloc) (void *ctx, void *ptr, size_t new_size)
+        void (*free) (void *ctx, void *ptr, size_t size)
+
+    ctypedef struct PyDataMem_Handler:
+        char* name
+        npy_uint8 version
+        PyDataMemAllocator allocator
+
+    object PyDataMem_SetHandler(object handler)
+    object PyDataMem_GetHandler()
+
     # additional datetime related functions are defined below
 
 

numpy/__init__.pxd

@@ -672,6 +672,23 @@ cdef extern from "numpy/arrayobject.h":
     npy_intp PyArray_OverflowMultiplyList (npy_intp *, int)
     int PyArray_SetBaseObject(ndarray, base) except -1 # NOTE: steals a reference to base! Use "set_array_base()" instead.
 
+    # The memory handler functions require the NumPy 1.22 API
+    # and may require defining NPY_TARGET_VERSION
+    ctypedef struct PyDataMemAllocator:
+        void *ctx
+        void* (*malloc) (void *ctx, size_t size)
+        void* (*calloc) (void *ctx, size_t nelem, size_t elsize)
+        void* (*realloc) (void *ctx, void *ptr, size_t new_size)
+        void (*free) (void *ctx, void *ptr, size_t size)
+
+    ctypedef struct PyDataMem_Handler:
+        char* name
+        npy_uint8 version
+        PyDataMemAllocator allocator
+
+    object PyDataMem_SetHandler(object handler)
+    object PyDataMem_GetHandler()
+
     # additional datetime related functions are defined below