plink.c

/*
** Routines processing configuration follow-set propagation links
** in the LEMON parser generator.
*/
static struct plink *plink_freelist = 0;

/* Allocate a new plink */
struct plink *Plink_new(void){
  struct plink *newlink;

  if( plink_freelist==0 ){
    int i;
    int amt = 100;
    plink_freelist = (struct plink *)calloc( amt, sizeof(struct plink) );
    if( plink_freelist==0 ){
      fprintf(stderr,
      "Unable to allocate memory for a new follow-set propagation link.\n");
      exit(1);
    }
    for(i=0; i<amt-1; i++) plink_freelist[i].next = &plink_freelist[i+1];
    plink_freelist[amt-1].next = 0;
  }
  newlink = plink_freelist;
  plink_freelist = plink_freelist->next;
  return newlink;
}

/* Add a plink to a plink list */
void Plink_add(struct plink **plpp, struct config *cfp)
{
  struct plink *newlink;
  newlink = Plink_new();
  newlink->next = *plpp;
  *plpp = newlink;
  newlink->cfp = cfp;
}

/* Transfer every plink on the list "from" to the list "to" */
void Plink_copy(struct plink **to, struct plink *from)
{
  struct plink *nextpl;
  while( from ){
    nextpl = from->next;
    from->next = *to;
    *to = from;
    from = nextpl;
  }
}

/* Delete every plink on the list */
void Plink_delete(struct plink *plp)
{
  struct plink *nextpl;

  while( plp ){
    nextpl = plp->next;
    plp->next = plink_freelist;
    plink_freelist = plp;
    plp = nextpl;
  }
}