Function npy_amerge_at

numpy/core/src/npysort/timsort.cpp:2549–2597

}

static int
npy_amerge_at(char *arr, npy_intp *tosort, const run *stack, const npy_intp at,
              buffer_intp *buffer, size_t len, PyArray_CompareFunc *cmp,
              PyArrayObject *py_arr)
{
    int ret;
    npy_intp s1, l1, s2, l2, k;
    npy_intp *p1, *p2;
    s1 = stack[at].s;
    l1 = stack[at].l;
    s2 = stack[at + 1].s;
    l2 = stack[at + 1].l;
    /* tosort[s2] belongs to tosort[s1+k] */
    k = npy_agallop_right(arr, tosort + s1, l1, arr + tosort[s2] * len, len,
                          cmp, py_arr);

    if (l1 == k) {
        /* already sorted */
        return 0;
    }

    p1 = tosort + s1 + k;
    l1 -= k;
    p2 = tosort + s2;
    /* tosort[s2-1] belongs to tosort[s2+l2] */
    l2 = npy_agallop_left(arr, tosort + s2, l2, arr + tosort[s2 - 1] * len,
                          len, cmp, py_arr);

    if (l2 < l1) {
        ret = resize_buffer_intp(buffer, l2);

        if (NPY_UNLIKELY(ret < 0)) {
            return ret;
        }

        npy_amerge_right(arr, p1, l1, p2, l2, buffer->pw, len, cmp, py_arr);
    }
    else {
        ret = resize_buffer_intp(buffer, l1);

        if (NPY_UNLIKELY(ret < 0)) {
            return ret;
        }

        npy_amerge_left(arr, p1, l1, p2, l2, buffer->pw, len, cmp, py_arr);
    }

    return 0;
}

static int
npy_atry_collapse(char *arr, npy_intp *tosort, run *stack, npy_intp *stack_ptr,