Function _umath_strings_richcompare

numpy/core/src/umath/string_ufuncs.cpp:329–449

* This function is used for `compare_chararrays` and currently also void * comparisons (unstructured voids). The first could probably be deprecated * and removed but is used by `np.char.chararray` the latter should also be * moved to the ufunc probably (removing the need for manual looping). * * The `rstrip` mechanism is presumably for some fortran compat, but the * question is whether it w

 *       `npy_byte` is correct.
 */
NPY_NO_EXPORT PyObject *
_umath_strings_richcompare(
        PyArrayObject *self, PyArrayObject *other, int cmp_op, int rstrip)
{
    NpyIter *iter = nullptr;
    PyObject *result = nullptr;

    char **dataptr = nullptr;
    npy_intp *strides = nullptr;
    npy_intp *countptr = nullptr;
    npy_intp size = 0;

    PyArrayMethod_Context context = {};
    NpyIter_IterNextFunc *iternext = nullptr;

    npy_uint32 it_flags = (
            NPY_ITER_EXTERNAL_LOOP | NPY_ITER_ZEROSIZE_OK |
            NPY_ITER_BUFFERED | NPY_ITER_GROWINNER);
    npy_uint32 op_flags[3] = {
            NPY_ITER_READONLY | NPY_ITER_ALIGNED,
            NPY_ITER_READONLY | NPY_ITER_ALIGNED,
            NPY_ITER_WRITEONLY | NPY_ITER_ALLOCATE | NPY_ITER_ALIGNED};

    PyArrayMethod_StridedLoop *strided_loop = nullptr;
    NPY_BEGIN_THREADS_DEF;

    if (PyArray_TYPE(self) != PyArray_TYPE(other)) {
        /*
         * Comparison between Bytes and Unicode is not defined in Py3K;
         * we follow.
         * TODO: This makes no sense at all for `compare_chararrays`, kept
         *       only under the assumption that we are more likely to deprecate
         *       than fix it to begin with.
         */
        Py_INCREF(Py_NotImplemented);
        return Py_NotImplemented;
    }

    PyArrayObject *ops[3] = {self, other, nullptr};
    PyArray_Descr *descrs[3] = {nullptr, nullptr, PyArray_DescrFromType(NPY_BOOL)};
    /* TODO: ensuring native byte order is not really necessary for == and != */
    descrs[0] = NPY_DT_CALL_ensure_canonical(PyArray_DESCR(self));
    if (descrs[0] == nullptr) {
        goto finish;
    }
    descrs[1] = NPY_DT_CALL_ensure_canonical(PyArray_DESCR(other));
    if (descrs[1] == nullptr) {
        goto finish;
    }

    /*
     * Create the iterator:
     */
    iter = NpyIter_AdvancedNew(
            3, ops, it_flags, NPY_KEEPORDER, NPY_SAFE_CASTING, op_flags, descrs,
            -1, nullptr, nullptr, 0);
    if (iter == nullptr) {
        goto finish;