source: branches/fscctrl_safety_limits/dim/src/dll.c

/*
 * A utility file. A double linked list.
 *
 * Started date   : 10-11-91
 * Written by     : C. Gaspar
 * UNIX adjustment: G.C. Ballintijn
 *
 */

#define DIMLIB
#include <dim.h>


void dll_init( DLL* head )
{
        DISABLE_AST
        head->next = head;
        head->prev = head;
        ENABLE_AST
}


void dll_insert_queue( DLL* head, DLL* item )
{
        register DLL *prevp;

        DISABLE_AST
        item->next = head;
        prevp = head->prev;
        item->prev = prevp;
        prevp->next = item;
        head->prev = item;
        ENABLE_AST
}       

void dll_insert_after( DLL* atitem, DLL* item )
{
        register DLL *auxp;

        DISABLE_AST
        auxp = atitem->next;
        item->next = auxp;
        item->prev = atitem;
        atitem->next = item;
        auxp->prev = item;
        ENABLE_AST
}       

DLL *dll_search( DLL* head, char *data, int size )
{
        register DLL *auxp= head->next;
 
        DISABLE_AST
        while( auxp!= head ) {
                if( !memcmp(auxp->user_info, data, (size_t)size) ) {
                        ENABLE_AST
                        return(auxp);
                }
                auxp = auxp->next;
        }
        ENABLE_AST
        return((DLL *)0);
}


DLL *dll_get_next( DLL* head, DLL* item )
{
        DISABLE_AST
        if( item->next != head ) {
                ENABLE_AST
                return(item->next);
        }
        ENABLE_AST
        return((DLL *) 0);
}

DLL *dll_get_prev( DLL* head, DLL* item )
{
        DISABLE_AST
        if( item->prev != head ) {
                ENABLE_AST
                return(item->prev);
        }
        ENABLE_AST
        return((DLL *) 0);
}

int dll_empty( DLL* head )
{
        DISABLE_AST
        if( head->next != head ) {
                ENABLE_AST
                return(0);
        }
        ENABLE_AST
        return(1);
}


void dll_remove( DLL* item ) 
{
        register DLL *prevp, *nextp;

        DISABLE_AST
        prevp = item->prev;
        nextp = item->next;
        prevp->next = item->next;
        nextp->prev = prevp;
        ENABLE_AST
}       

DLL *dll_search_next_remove( DLL* head, int offset, char *data, int size )
{
        register DLL *auxp= head->next;
        DLL *retp = 0;
 
        DISABLE_AST
        while( auxp!= head ) {
                if( !memcmp(&(auxp->user_info[offset]), data, (size_t)size) ) {
                        retp = auxp;
                }
                auxp = auxp->next;
        }
        if( retp)
        {
                dll_remove(retp);
                ENABLE_AST
                return(retp);
        }
        ENABLE_AST
        return((DLL *)0);
}