Function npy_merge_at

numpy/core/src/npysort/timsort.cpp:2117–2165

}

static int
npy_merge_at(char *arr, const run *stack, const npy_intp at,
             buffer_char *buffer, size_t len, PyArray_CompareFunc *cmp,
             PyArrayObject *py_arr)
{
    int ret;
    npy_intp s1, l1, s2, l2, k;
    char *p1, *p2;
    s1 = stack[at].s;
    l1 = stack[at].l;
    s2 = stack[at + 1].s;
    l2 = stack[at + 1].l;
    /* arr[s2] belongs to arr[s1+k] */
    GENERIC_COPY(buffer->pw, arr + s2 * len, len);
    k = npy_gallop_right(arr + s1 * len, l1, buffer->pw, len, cmp, py_arr);

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

    p1 = arr + (s1 + k) * len;
    l1 -= k;
    p2 = arr + s2 * len;
    /* arr[s2-1] belongs to arr[s2+l2] */
    GENERIC_COPY(buffer->pw, arr + (s2 - 1) * len, len);
    l2 = npy_gallop_left(arr + s2 * len, l2, buffer->pw, len, cmp, py_arr);

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

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

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

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

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

    return 0;
}

static int
npy_try_collapse(char *arr, run *stack, npy_intp *stack_ptr,