lld.c

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    Retval = LLDnodeInsertFrom( List, DataPtr );

    va_end( DataPtr );
    return Retval ;
}

int LLDnodeAdd( int List, ... )          /* insert _AFTER_ current node */
{
    va_list DataPtr ;
    int Retval ;

    /* set DataPtr to the address of "..."
       then action, cleanup and return.
    */
    va_start( DataPtr, List );

    Retval = LLDnodeAddFrom( List, DataPtr );

    va_end( DataPtr );
    return Retval ;
}

int LLDnodePrepend( int List, ... )             /* insert as first node */
{
    va_list DataPtr ;
    int Retval ;

    /* set DataPtr to the address of "..."
       then action, cleanup and return.
    */
    va_start( DataPtr, List );

    Retval = LLDnodePrependFrom( List, DataPtr );

    va_end( DataPtr );
    return Retval ;
}

int LLDnodeAppend( int List, ... )               /* insert as last node */
{
    va_list DataPtr ;
    int Retval ;

    /* set DataPtr to the address of "..."
       then action, cleanup and return.
    */
    va_start( DataPtr, List );

    Retval = LLDnodeAppendFrom( List, DataPtr );

    va_end( DataPtr );
    return Retval ;
}

int LLDnodeInsertFrom( int List, void * Source )
{                                       /* insert _BEFORE_ current node */
    struct Node * New ;

    assert( (unsigned) List < ListCount );

    /* create new node if possible
    */
    New = NODE_MALLOC( List );
    if( NULL == New )
    {
        return ERR_MEMORY ;
    }

    /* fill node with data, link to next and previous nodes
       and adjust current node pointer
    */
    memcpy( & New->data, Source, ListControl[ List ].itemsize );
    New->next = ListControl[ List ].current;
    New->prev = ListControl[ List ].current->prev;

    ListControl[ List ].current->prev = New ;
    New->prev->next = New ;

    ListControl[ List ].current = New ;

    return NO_PROBLEMS;
}

int LLDnodeAddFrom( int List, void * Source )
{                                        /* insert _AFTER_ current node */
    struct Node * New ;

    assert( (unsigned) List < ListCount );

    /* create new node if possible
    */
    New = NODE_MALLOC( List );
    if( NULL == New )
    {
        return ERR_MEMORY ;
    }

    /* fill node with data and link to next and previous nodes
       with special handling when the current node pointer points
       to the dummy tail node: i.e it is an empty list.
       (the same case in a non-empty list is made not to occur.)
    */
    memcpy( & New->data, Source, ListControl[ List ].itemsize );

    if( NULL != ListControl[ List ].current->next )
        ListControl[ List ].current = ListControl[ List ].current->next ;

    New->next = ListControl[ List ].current;
    New->prev = ListControl[ List ].current->prev;

    ListControl[ List ].current->prev = New ;
    New->prev->next = New ;

    ListControl[ List ].current = New ;

    return NO_PROBLEMS;
}

int LLDnodePrependFrom( int List, void * Source )
{                                               /* insert as first node */
    struct Node * New ;

    assert( (unsigned) List < ListCount );

    /* create new node if possible
    */
    New = NODE_MALLOC( List );
    if( NULL == New )
    {
        return ERR_MEMORY ;
    }

    /* fill node with data and link to dummy head and actual first nodes
    */
    memcpy( & New->data, Source, ListControl[ List ].itemsize );
    New->prev = ListControl[ List ].first;     /* == .first->next->prev */
    New->next = ListControl[ List ].first->next;

    ListControl[ List ].first->next = New;
    New->next->prev = New ;

    /* Prevent .current from pointing at the dummy tail
       (New is the only normal node...)
    */
    if( NULL == ListControl[ List ].current->next )
        ListControl[ List ].current = New;

    return NO_PROBLEMS;
}

int LLDnodeAppendFrom( int List, void * Source )
{                                                /* insert as last node */
    struct Node * New ;

    assert( (unsigned) List < ListCount );

    /* create new node if possible
    */
    New = NODE_MALLOC( List );
    if( NULL == New )
    {
        return ERR_MEMORY ;
    }

    /* fill node with data and link to dummy tail and actual last nodes
    */
    memcpy( & New->data, Source, ListControl[ List ].itemsize );
    New->next = ListControl[ List ].last ;      /* == .last->prev->next */
    New->prev = ListControl[ List ].last->prev;

    ListControl[ List ].last->prev = New ;
    New->prev->next = New ;

    /* Prevent .current from pointing at the dummy tail
       (New is the only normal node...)
    */
    if( NULL == ListControl[ List ].current->next )
        ListControl[ List ].current = New;

    return NO_PROBLEMS;
}

void LLDnodeDelete( int List )
{
    struct Node * Old = ListControl[ List ].current ;

    assert( (unsigned) List < ListCount );

    if( NULL == ListControl[ List ].current->next )
    {
        return ;  /* don't delete dummy tail node (list is empty) */
    }

    /* adjust links
    */
    Old->prev->next = Old->next ;
    Old->next->prev = Old->prev ;

    /* adjust current node pointer
       prevent it from pointing to the dummy tail node
    */
    if( NULL != Old->next->next )
        ListControl[ List ].current = Old->next ;
    else
        ListControl[ List ].current = Old->prev ;

    NODE_FREE( Old );

    return ;
}

int LLDnodeFind( int List, CompFunPtr Compare, void * DataPtr )
{                        /* FindFirst/FindNext format may be needed ... */
    int RetVal ;

    assert( (unsigned) List < ListCount );

    if( NULL == ListControl[ List ].first->next->next ) /* empty list ? */
    {
        return 2; /* a compare usually returns just -1, 0 or 1 !!! */
    }

    /* note: current->next will never be NULL in a non-empty list */

    if( NULL == Compare ) /* default to memcmp with .itemsize */
    {
        while( 0 != (RetVal = memcmp( DataPtr,
                                      & ListControl[ List ].current->data,
                                      ListControl[ List ].itemsize ))
               && NULL != ListControl[ List ].current->next->next )
        {
            ListControl[ List ].current=ListControl[ List ].current->next;
        }
        return RetVal ;
    }
    else
    {
        while( 0 != (RetVal = (*Compare)( DataPtr,
                                   & ListControl[ List ].current->data ))
               && NULL != ListControl[ List ].current->next->next )
        {
            ListControl[ List ].current=ListControl[ List ].current->next;
        }
        return RetVal ;
    }
}

/* ---- current node pointer management ------------------------------- */

int  LLDnodePtr2First( int List )
{
    assert( (unsigned) List < ListCount );

    ListControl[ List ].current = ListControl[ List ].first->next ;

    return NULL != ListControl[ List ].first->next->next ;
}

int  LLDnodePtr2Last( int List )
{
    assert( (unsigned) List < ListCount );

    ListControl[ List ].current = ListControl[ List ].last->prev ;

    return NULL != ListControl[ List ].last->prev->prev ;
}

int  LLDnodePtr2Next( int List )
{
    assert( (unsigned) List < ListCount );

    if( NULL == ListControl[ List ].current->next       /* empty list ? */
        || NULL == ListControl[ List ].current->next->next ) /* at end ?*/
    {
        return 0 ;             /* do not allow the current node pointer */
    }                          /* to point at the dummy tail node ...   */

    ListControl[ List ].current = ListControl[ List ].current->next ;
    return 1 ;
}

int  LLDnodePtr2Prev( int List )
{
    assert( (unsigned) List < ListCount );

    if( NULL == ListControl[ List ].current->prev       /* empty list ? */
        || NULL == ListControl[ List ].current->prev->prev ) /* begin ? */
    {
        return 0 ;             /* do not allow the current node pointer */
    }                          /* to point at the dummy head node ...   */

    ListControl[ List ].current = ListControl[ List ].current->prev ;
    return 1 ;
}

/* ---- stored data management ---------------------------------------- */

int LLDnodeInt( int List )
{
    return ListControl[ List ].current->data;
}

long LLDnodeLong( int List )
{
    return *((long *) &ListControl[ List ].current->data );
}

void * LLDnodePtr( int List )
{
    return *((void **) &ListControl[ List ].current->data );
}

void FAR * LLDnodeFptr( int List )
{
    return *((void FAR **) &ListControl[ List ].current->data );
}

int LLDnodeDataTo( int List, void * Destination )
{
    if( NULL != Destination )
    {
        memcpy( Destination,
                & ListControl[ List ].current->data,
                ListControl[ List ].itemsize );
    }

    return ListControl[ List ].itemsize ;       /* size needed for blob */
}

/* ==== LLD.c  end ==================================================== */