Function cvGraphRemoveEdgeByPtr

deps/opencv/modules/core/src/datastructs.cpp:2832–2887

Remove the graph edge connecting two given vertices: */

/* Remove the graph edge connecting two given vertices: */
CV_IMPL void
cvGraphRemoveEdgeByPtr( CvGraph* graph, CvGraphVtx* start_vtx, CvGraphVtx* end_vtx )
{
    int ofs, prev_ofs;
    CvGraphEdge *edge, *next_edge, *prev_edge;

    if( !graph || !start_vtx || !end_vtx )
        CV_Error( CV_StsNullPtr, "" );

    if( start_vtx == end_vtx )
        return;

    if( !CV_IS_GRAPH_ORIENTED( graph ) &&
        (start_vtx->flags & CV_SET_ELEM_IDX_MASK) > (end_vtx->flags & CV_SET_ELEM_IDX_MASK) )
    {
        CvGraphVtx* t;
        CV_SWAP( start_vtx, end_vtx, t );
    }

    for( ofs = prev_ofs = 0, prev_edge = 0, edge = start_vtx->first; edge != 0;
         prev_ofs = ofs, prev_edge = edge, edge = edge->next[ofs] )
    {
        ofs = start_vtx == edge->vtx[1];
        assert( ofs == 1 || start_vtx == edge->vtx[0] );
        if( edge->vtx[1] == end_vtx )
            break;
    }

    if( !edge )
        return;

    next_edge = edge->next[ofs];
    if( prev_edge )
        prev_edge->next[prev_ofs] = next_edge;
    else
        start_vtx->first = next_edge;

    for( ofs = prev_ofs = 0, prev_edge = 0, edge = end_vtx->first; edge != 0;
         prev_ofs = ofs, prev_edge = edge, edge = edge->next[ofs] )
    {
        ofs = end_vtx == edge->vtx[1];
        assert( ofs == 1 || end_vtx == edge->vtx[0] );
        if( edge->vtx[0] == start_vtx )
            break;
    }

    assert( edge != 0 );

    next_edge = edge->next[ofs];
    if( prev_edge )
        prev_edge->next[prev_ofs] = next_edge;
    else
        end_vtx->first = next_edge;

    cvSetRemoveByPtr( graph->edges, edge );
}