__inline void remove_free_block(memmap_free_t* mmap) {
memmap_t* mmap_alloc = (memmap_t*)mmap;
U8 index = get_free_bucket_index(get_block_size(mmap_alloc));
if (!is_last_in_bucket(mmap)) {
if (!is_first_in_bucket(mmap)) {
set_next_free(get_prev_free(mmap), get_next_free(mmap));
set_prev_free(get_next_free(mmap), get_prev_free(mmap));
}
else {
mprgmmap[index] = get_next_free(mmap);
set_prev_free(get_next_free(mmap), get_next_free(mmap));
}
}
else {
if (!is_first_in_bucket(mmap)) {
set_next_free(get_prev_free(mmap), get_prev_free(mmap));
}
else {
mprgmmap[index] = NULL;
}
}
// "Isolating" the block
set_prev_free(mmap, mmap);
set_next_free(mmap, mmap);
}
/*
void memmap_free_init(memmap_free_t* const mmap, U32 size)
Initializes a struct of type `memmap_free` with a given size.
*/
void memmap_free_init(memmap_free_t* const mmap, U32 size) {
// memmap is the first field in memmap_free_t
memmap_t* memmap_alloc = (memmap_t*)(mmap);
memmap_init(memmap_alloc, size);
set_prev_free(mmap, mmap);
set_next_free(mmap, mmap);
}
/* relase po with size N to AVAIL list */
void dkbtfree(void * x){
assert(x!=NULL);
node_t * po=x;
node_t * block;
block=block_merge_left(get_block_pprv(po), po);
block=block_merge_right(block, get_block_pnxt(block));/* return new block */
set_block_free(block);
set_prev_free(get_block_pnxt(block));
set_prev_used(block);
block_insert(block); /*insert into dll */
}
// Macro is evil, inline function is more reliable.
static inline void insert_node(int level, void * bp) {
char **flist_head = get_head(level);
char **flist_tail = get_tail(level);
if (!(*flist_head)) {
// empty list
*flist_head = bp;
*flist_tail = bp;
set_prev_free(bp, NULL);
set_next_free(bp, NULL);
} else {
if ((char *)bp < (*flist_head)) {
// insert at head
set_prev_free(*flist_head, bp);
set_next_free(bp, *flist_head);
set_prev_free(bp, NULL);
*flist_head = bp;
} else if ((*flist_tail) < (char *)bp) {
// insert to tail
set_next_free(*flist_tail, bp);
set_prev_free(bp, *flist_tail);
set_next_free(bp, NULL);
*flist_tail = bp;
} else {
// find some place in the list
char * c = *flist_head;
while (c < (char *)bp) {
c = next_free(c);
}
set_next_free(prev_free(c), bp);
set_prev_free(bp, prev_free(c));
set_prev_free(c, bp);
set_next_free(bp, c);
}
}
}
static inline void delete_node(int level, void * bp) {
char **flist_head = get_head(level);
char **flist_tail = get_tail(level);
if (bp == *flist_head) {
*flist_head = next_free(bp);
if (*flist_head) {
set_prev_free(*flist_head, NULL);
} else {
*flist_tail = NULL;
}
} else if (bp == *flist_tail) {
*flist_tail = prev_free(bp);
if (*flist_tail) {
set_next_free(*flist_tail, NULL);
} else {
*flist_head = NULL;
}
} else {
set_next_free(prev_free(bp), next_free(bp));
set_prev_free(next_free(bp), prev_free(bp));
}
}
/*
* extend_heap - Extend heap with free block and return its block pointer
*
* Return:
* the new free block pointer
*/
static void *extend_heap(size_t words)
{
char *bp;
size_t size;
/* single-word alignment */
size = (words + 1) * WSIZE;
if ((long)(bp = mem_sbrk(size)) == -1)
return NULL;
int prev_alloc = IS_PREV_ALLOC(HDRP(bp));
/* Initialize free block header/footer and the epilogue header */
PUT(HDRP(bp), PACK3(size, prev_alloc << 1, 0)); /* Free block header */
PUT(FTRP(bp), PACK3(size, prev_alloc << 1, 0)); /* Free block footer */
set_prev_free(bp, NULL);
set_next_free(bp, NULL);
PUT(HDRP(NEXT_BLKP(bp)), PACK(0, 1)); /* New epilogue header */
/* Coalesce if the previous block was free */
heap_tailp = coalesce(bp);
return heap_tailp;
}
