Logic behind showing the previously liked buttons as Unlike

I have 2 different tables: reputation and posts. POSTS have details related to it like post_id, user_id, post_content... and so on. REPUTATION have details like post_id and user_id. If a pair exists in the table then the post_id has been +1'ed by the user_id.

On my homepage, I'm using pagination to display 5 posts/page and only fetching from the POSTS table. Further I'm trying to fetch the 'post_id' from REPUTATION table for the 'user_id' in $_SESSION.

public function index()
{
    $this->load->model('themodel');
    $this->load->library('pagination');
    $config['base_url'] = site_url('trial/index');
    $config['total_rows'] = $this->themodel->total_rows('posts');
    $config['per_page'] = 5;
    //$config['display_pages'] = FALSE;
    $this->pagination->initialize($config);

    $offset = $this->uri->segment(3);

    $data['details'] = $this->themodel->list_posts($config['per_page'], $offset);

    $data['links'] = $this->pagination->create_links();


    //Check for session and load the reputation data
    if($this->session->userdata('loggedIn') && $this->session->userdata('user'))
    {
        //fetch reputation by user
        $data['repbyuser'] = $this->themodel->getrepbyuser();
    }

    $this->load->view('home_view', $data);

}

In the model part:

public function list_posts($limit, $start)
{
    $this->db->select('post_id, user_id, post_title, post_content, total_reputation, post_time, total_reviews');
    return $this->db->get('posts', $limit, $start)->result_array();
}

public function getrepbyuser()
    {
        $this->db->select('post_id');
        $this->db->where('user_id', $this->session->userdata('user'));
        $result = $this->db->get('reputation');
        if($result->num_rows() > 0)
            return $result->result_array();
    }

Now on my homepage I'm traversing the $details array but I'm not sure how to match the results from both the table.

If I'm doing anything wrong please guide. Any suggestion would be appreciated.

function getrepbyuser()
{
    $data   = array();
    $this->db->select('post_id');
    $this->db->where('user_id', $this->session->userdata('user'));
    $result = $this->db->get('reputation');
    if($result->num_rows() > 0){
        //return $result->result_array();
        $temp   = $result->result_array();
        foreach( $temp as $each ){ #for returning a single dimentional array
            $data[] = $each['post_id'];
        }
    }
    return $data;       
}

Now in the view page you will do:

foreach( $details as $each ){   #loop for the posts
    $liked  = false;
    if( in_array($key['post_id'], $repbyuser) ){    #check if the post is liked or not
        $liked  = true;
    }

    if( $liked ){
        #button for dislike
    }else{
        #button for like
    }
}