void freef(char *p)
{
printf("freef called with p=%p\n", (void *) p);
if(p!=0){
/* you write the code for the freef function here */
struct blockl *temp = (struct blockl *)p;
temp->tag = FREETAG;
char *temp2 = p;
temp2 += temp->size;
temp2 += (TAGSIZE*2);
struct blockr *temp3 = (struct blockr *)temp2;
temp3->tag = FREETAG;
struct blockr *temp4 = (struct blockr *)(p - TAGSIZE);
//temp4 -= 1;
if (temp4->tag == FREETAG) {
struct blockl *temp5 = (struct blockl *)(temp4 - temp4->size-(TAGSIZE));
coalesce(temp5, temp);
}
else{
enchain(temp);
}
temp2 += TAGSIZE;
struct blockl *temp6 = (struct blockl *)temp2;
if (temp6->tag == FREETAG){
unchain(temp6);
coalesce(temp, temp6);
}
}
}
void chain_back(T *i)
{
if (_active_back == NULL)
{
unchain(i);
_active_front = (list_item<T>*)i;
_active_back = _active_front;
return;
}
chain_next(_active_back, (list_item<T>*)i);
}
void chain_front(T *i)
{
if (_active_front == NULL)
{
unchain(i);
_active_front = (list_item<T>*)i;
_active_back = _active_front;
return;
}
chain_prev(_active_front, (list_item<T>*)i);
}
void chain_prev(list_item<T> *a, list_item<T> *b)
{
if (a == b) return;
unchain((T*)b);
if (a->prev == NULL) _active_front = b;
else a->prev->next = b;
b->prev = a->prev;
b->next = a;
a->prev = b;
}
void chain_next(list_item<T> *a, list_item<T> *b)
{
if (a == b) return;
unchain((T*)b);
if (a->next == NULL) _active_back = b;
else a->next->prev = b;
b->next = a->next;
b->prev = a;
a->next = b;
}
void freef(void *f)
{
struct blockl *q;
struct blockr *r;
struct blockl *s;
char *p = (char *)f;
printf("freef called with p=%p\n", p);
if (p < allocbuf || p > allocbuf + ALLOCSIZE) {
printf("freef: bad pointer to block to be freed, %p\n", (void *) p);
return;
}
p = p - TAGSIZE; /* undo offset added by alloc() */
q = (struct blockl *) p; /* make pointer to struct blockl */
if (q->tag != USEDTAG) {
printf("freef: block being freed is not in use, %p\n", (void *) p);
return;
}
r = (struct blockr *) (p + q->size - TAGSIZE); /* point to blockr */
if (r->tag != USEDTAG) {
printf("freef: block being freed is not in use, %p\n", (void *) p);
return;
}
q->tag = (r->tag = FREETAG); /* set tags to show it is free */
r->size = q->size; /* set size in blockr */
/* look for opportunity to coalesce */
/* with next lower block */
r = (struct blockr *) (p - TAGSIZE);
if ((char *) r >= allocbuf && r->tag == FREETAG) {
s = (struct blockl *) (p - r->size);
p = p - r->size;
coalesce(s,q);
q = s;
} else
enchain(q); /* return to the free list */
/* look for opportunity to coalesce */
/* with next higher block */
s = (struct blockl *) (p + q->size);
if ((char *) s < allocbuf + ALLOCSIZE && s->tag == FREETAG) {
unchain(s);
coalesce(q,s);
}
}
void remove(T *i)
{
unchain(i);
_alloc->remove((list_item<T>*)i);
}
