/*
* malloc
*/
void *malloc (size_t size) {
checkheap(1); // Let's make sure the heap is ok!
unsigned int awords; //Adjusted block size
unsigned int ewords; //Amount to extend heap if no matching
uint32_t *block;
uint32_t * heap_lastp = last_block();
if (VERBOSE)
printf("Malloc %d bytes\n", (int)size);
/* Ignore 0 requests */
if (size == 0)
return NULL;
/* Adjust size to include alignment and convert to multipes of 4 bytes */
if (size <= DSIZE)
awords = 2;
else
awords = (((size) + (DSIZE-1)) & ~0x7) / WSIZE;
/* Search the free list for a fit */
if ((block = find_fit(awords)) != NULL) {
place(block, awords);
//printf("3\n");
return block_mem(block);
}
/* No fit found. Get more memory and place the block */
if (awords > CHUNKSIZE)
ewords = awords;
else if (0)
ewords = awords;
else
ewords = CHUNKSIZE;
if (block_free(heap_lastp)) {
ENSURES(block_size(heap_lastp) < ewords);
ewords = ewords - block_size(heap_lastp) + 2;
//ewords += 2;
//printf("1\n");
} else {
ewords += 2; // ask for 2 more for the header and footer
//printf("2\n");
}
if ((block = extend_heap(ewords)) == NULL)
return NULL;
place(block, awords);
return block_mem(block);
}
//Find the first fit
static void *find_first_fit(size_t size) {
uint32_t *ptr = (uint32_t *)heap_ptr + 2;
unsigned int bsize = block_size(ptr);
while(bsize > 0) {
if((size <= bsize) && !block_free(ptr))
return (void *)block_mem(ptr);
ptr = block_next(ptr);
bsize = block_size(ptr);
}
return NULL;
}
// Returns 0 if no errors were found, otherwise returns the error
int mm_checkheap(int verbose) {
void* current;
//void* prev;
size_t size;
for(int i = 0; i < NUM_FREE_LISTS; i++){
current = free_lists[i];
//prev = NULL;
while(current != NULL){
if(!in_heap(current)){
if(verbose) printf("HEAP ERROR: block not in heap\n");
printf("CURRENT: %p\n", current);
return 1;
}
size = block_size(current);
if(size > MAX_SIZE){
if(verbose) printf("HEAP ERROR: invalid block size\n");
return 1;
}
/*
if(block_prev(current) != prev){
if(verbose) printf("HEAP ERROR: invalid prev pointer\n");
return 1;
}
*/
if(!block_free(current)){
if(verbose) printf("HEAP ERROR: block in list not marked free\n");
return 1;
}
if(!aligned(current) || !aligned(block_mem(current))){
if(verbose) printf("HEAP ERROR: block not aligned\n");
return 1;
}
//prev = current;
current = block_next(current);
}
}
return 0;
}
/*
* malloc
*/
void *malloc (size_t size) {
void* p;
int index;
if(heap_start == 0)
mm_init();
checkheap(1); // Let's make sure the heap is ok!
if(size == 0) return NULL;
size += 8 - size%8;
size += (HEADER_SIZE + FOOTER_SIZE);
if(size > MAX_SIZE) return NULL;
index = get_free_list_index(size);
p = find_free_block(index, size);
if(p == NULL) return NULL;
p = block_mem(p);
checkheap(1);
return p;
}
