Function npy_force_collapse

numpy/core/src/npysort/timsort.cpp:2227–2268

}

static int
npy_force_collapse(char *arr, run *stack, npy_intp *stack_ptr,
                   buffer_char *buffer, size_t len, PyArray_CompareFunc *cmp,
                   PyArrayObject *py_arr)
{
    int ret;
    npy_intp top = *stack_ptr;

    while (2 < top) {
        if (stack[top - 3].l <= stack[top - 1].l) {
            ret = npy_merge_at(arr, stack, top - 3, buffer, len, cmp, py_arr);

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

            stack[top - 3].l += stack[top - 2].l;
            stack[top - 2] = stack[top - 1];
            --top;
        }
        else {
            ret = npy_merge_at(arr, stack, top - 2, buffer, len, cmp, py_arr);

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

            stack[top - 2].l += stack[top - 1].l;
            --top;
        }
    }

    if (1 < top) {
        ret = npy_merge_at(arr, stack, top - 2, buffer, len, cmp, py_arr);

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

    return 0;
}

NPY_NO_EXPORT int
npy_timsort(void *start, npy_intp num, void *varr)