tree.c

VLC Player Source Code

playlist_item_t * playlist_GetPreferredNode( playlist_t *p_playlist,
                                             playlist_item_t *p_node )
{
    PL_ASSERT_LOCKED;
    int i;
    if( p_node->p_parent == p_playlist->p_root_category )
    {
        if( p_playlist->b_tree || p_node->p_input->b_prefers_tree )
            return p_node;
        for( i = 0 ; i< p_playlist->p_root_onelevel->i_children; i++ )
        {
            if( p_playlist->p_root_onelevel->pp_children[i]->p_input->i_id ==
                    p_node->p_input->i_id )
                return p_playlist->p_root_onelevel->pp_children[i];
        }
    }
    else if( p_node->p_parent == p_playlist->p_root_onelevel )
    {
        if( !p_playlist->b_tree || !p_node->p_input->b_prefers_tree )
            return p_node;
        for( i = 0 ; i< p_playlist->p_root_category->i_children; i++ )
        {
            if( p_playlist->p_root_category->pp_children[i]->p_input->i_id ==
                    p_node->p_input->i_id )
                return p_playlist->p_root_category->pp_children[i];
        }
    }
    return NULL;
}

/**********************************************************************
 * Tree walking functions
 **********************************************************************/

playlist_item_t *playlist_GetLastLeaf(playlist_t *p_playlist,
                                      playlist_item_t *p_root )
{
    PL_ASSERT_LOCKED;
    int i;
    playlist_item_t *p_item;
    for ( i = p_root->i_children - 1; i >= 0; i-- )
    {
        if( p_root->pp_children[i]->i_children == -1 )
            return p_root->pp_children[i];
        else if( p_root->pp_children[i]->i_children > 0)
        {
             p_item = playlist_GetLastLeaf( p_playlist,
                                            p_root->pp_children[i] );
            if ( p_item != NULL )
                return p_item;
        }
        else if( i == 0 )
            return NULL;
    }
    return NULL;
}

/**
 * Finds the next item to play
 *
 * \param p_playlist the playlist
 * \param p_root the root node
 * \param p_item the previous item  (NULL if none )
 * \return the next item to play, or NULL if none found
 */
playlist_item_t *playlist_GetNextLeaf( playlist_t *p_playlist,
                                       playlist_item_t *p_root,
                                       playlist_item_t *p_item,
                                       bool b_ena, bool b_unplayed )
{
    PL_ASSERT_LOCKED;
    playlist_item_t *p_next;

    assert( p_root && p_root->i_children != -1 );

    PL_DEBUG2( "finding next of %s within %s",
               PLI_NAME( p_item ), PLI_NAME( p_root ) );

    /* Now, walk the tree until we find a suitable next item */
    p_next = p_item;
    while( 1 )
    {
        bool b_ena_ok = true, b_unplayed_ok = true;
        p_next = GetNextItem( p_playlist, p_root, p_next );
        if( !p_next || p_next == p_root )
            break;
        if( p_next->i_children == -1 )
        {
            if( b_ena && p_next->i_flags & PLAYLIST_DBL_FLAG )
                b_ena_ok = false;
            if( b_unplayed && p_next->p_input->i_nb_played != 0 )
                b_unplayed_ok = false;
            if( b_ena_ok && b_unplayed_ok ) break;
        }
    }
    if( p_next == NULL ) PL_DEBUG2( "at end of node" );
    return p_next;
}

/**
 * Finds the previous item to play
 *
 * \param p_playlist the playlist
 * \param p_root the root node
 * \param p_item the previous item  (NULL if none )
 * \return the next item to play, or NULL if none found
 */
playlist_item_t *playlist_GetPrevLeaf( playlist_t *p_playlist,
                                       playlist_item_t *p_root,
                                       playlist_item_t *p_item,
                                       bool b_ena, bool b_unplayed )
{
    PL_ASSERT_LOCKED;
    playlist_item_t *p_prev;

    PL_DEBUG2( "finding previous os %s within %s", PLI_NAME( p_item ),
                                                   PLI_NAME( p_root ) );
    assert( p_root && p_root->i_children != -1 );

    /* Now, walk the tree until we find a suitable previous item */
    p_prev = p_item;
    while( 1 )
    {
        bool b_ena_ok = true, b_unplayed_ok = true;
        p_prev = GetPrevItem( p_playlist, p_root, p_prev );
        if( !p_prev || p_prev == p_root )
            break;
        if( p_prev->i_children == -1 )
        {
            if( b_ena && p_prev->i_flags & PLAYLIST_DBL_FLAG )
                b_ena_ok = false;
            if( b_unplayed && p_prev->p_input->i_nb_played != 0 )
                b_unplayed_ok = false;
            if( b_ena_ok && b_unplayed_ok ) break;
        }
    }
    if( p_prev == NULL ) PL_DEBUG2( "at beginning of node" );
    return p_prev;
}

/************************************************************************
 * Following functions are local
 ***********************************************************************/

/**
 * Get the next item in the tree
 * If p_item is NULL, return the first child of root
 **/
playlist_item_t *GetNextItem( playlist_t *p_playlist,
                              playlist_item_t *p_root,
                              playlist_item_t *p_item )
{
    playlist_item_t *p_parent;
    int i;

    /* Node with children, get the first one */
    if( p_item && p_item->i_children > 0 )
        return p_item->pp_children[0];

    if( p_item != NULL )
        p_parent = p_item->p_parent;
    else
        p_parent = p_root;
    for( i= 0 ; i < p_parent->i_children ; i++ )
    {
        if( p_item == NULL || p_parent->pp_children[i] == p_item )
        {
            if( p_item == NULL )
                i = -1;

            if( i+1 >= p_parent->i_children )
            {
                /* Was already the last sibling. Look for uncles */
                PL_DEBUG2( "Current item is the last of the node,"
                           "looking for uncle from %s",
                            p_parent->p_input->psz_name );

                if( p_parent == p_root )
                {
                    PL_DEBUG2( "already at root" );
                    return NULL;
                }
                return GetNextUncle( p_playlist, p_item, p_root );
            }
            else
            {
                return  p_parent->pp_children[i+1];
            }
        }
    }
    return NULL;
}

playlist_item_t *GetNextUncle( playlist_t *p_playlist, playlist_item_t *p_item,
                               playlist_item_t *p_root )
{
    playlist_item_t *p_parent = p_item->p_parent;
    playlist_item_t *p_grandparent;
    bool b_found = false;

    (void)p_playlist;

    if( p_parent != NULL )
    {
        p_grandparent = p_parent->p_parent;
        while( p_grandparent )
        {
            int i;
            for( i = 0 ; i< p_grandparent->i_children ; i++ )
            {
                if( p_parent == p_grandparent->pp_children[i] )
                {
                    PL_DEBUG2( "parent %s found as child %i of grandparent %s",
                               p_parent->p_input->psz_name, i,
                               p_grandparent->p_input->psz_name );
                    b_found = true;
                    break;
                }
            }
            if( b_found && i + 1 < p_grandparent->i_children )
            {
                    return p_grandparent->pp_children[i+1];
            }
            /* Not found at root */
            if( p_grandparent == p_root )
            {
                return NULL;
            }
            else
            {
                p_parent = p_grandparent;
                p_grandparent = p_parent->p_parent;
            }
        }
    }
    /* We reached root */
    return NULL;
}

playlist_item_t *GetPrevUncle( playlist_t *p_playlist, playlist_item_t *p_item,
                               playlist_item_t *p_root )
{
    playlist_item_t *p_parent = p_item->p_parent;
    playlist_item_t *p_grandparent;
    bool b_found = false;

    (void)p_playlist;

    if( p_parent != NULL )
    {
        p_grandparent = p_parent->p_parent;
        while( 1 )
        {
            int i;
            for( i = p_grandparent->i_children -1 ; i >= 0; i-- )
            {
                if( p_parent == p_grandparent->pp_children[i] )
                {
                    b_found = true;
                    break;
                }
            }
            if( b_found && i - 1 > 0 )
            {
                return p_grandparent->pp_children[i-1];
            }
            /* Not found at root */
            if( p_grandparent == p_root )
            {
                return NULL;
            }
            else
            {
                p_parent = p_grandparent;
                p_grandparent = p_parent->p_parent;
            }
        }
    }
    /* We reached root */
    return NULL;
}


/* Recursively search the tree for previous item */
playlist_item_t *GetPrevItem( playlist_t *p_playlist,
                              playlist_item_t *p_root,
                              playlist_item_t *p_item )
{
    playlist_item_t *p_parent;
    int i;

    /* Node with children, get the last one */
    if( p_item && p_item->i_children > 0 )
        return p_item->pp_children[p_item->i_children - 1];

    /* Last child of its parent ? */
    if( p_item != NULL )
        p_parent = p_item->p_parent;
    else
    {
        msg_Err( p_playlist, "Get the last one" );
        abort();
    };

    for( i = p_parent->i_children -1 ; i >= 0 ;  i-- )
    {
        if( p_parent->pp_children[i] == p_item )
        {
            if( i-1 < 0 )
            {
               /* Was already the first sibling. Look for uncles */
                PL_DEBUG2( "current item is the first of its node,"
                           "looking for uncle from %s",
                           p_parent->p_input->psz_name );
                if( p_parent == p_root )
                {
                    PL_DEBUG2( "already at root" );
                    return NULL;
                }
                return GetPrevUncle( p_playlist, p_item, p_root );
            }
            else
            {
                return p_parent->pp_children[i-1];
            }
        }
    }
    return NULL;
}