void *mm_malloc(size_t size) {
if (size > 0) {
if (!start) {
start = request_space(size);
if (!start) {
return NULL;
}
start->free = 0;
last = start;
return start+1;
} else {
struct metadata *block;
block = find_block(size);
if (!block) {
block = request_space(size);
if (!block) {
return NULL;
}
} else {
if ((block->size - size) >= (sizeof(struct metadata))) {
split(block, size);
}
}
block->free = 0;
void *ptr = (void *)block + sizeof(struct metadata);
memset(ptr, 0, size);
return ptr;
}
}
return NULL;
}
char *
malloc(size_t size) {
struct malloc_chunk *block;
if (size <= 0) {
return NULL;
}
if (!heap_start) { // First call.
block = request_space(NULL, size);
if (!block) {
return NULL;
}
heap_start = (char*) block;
} else {
struct malloc_chunk *last = (struct malloc_chunk*) heap_start;
block = find_free_block(&last, size);
if (!block) { // Failed to find free block.
block = request_space(last, size);
if (!block) {
return NULL;
}
} else {
// Found a block we can re-use
/*
if ((block->size - size) > (31+MALLOC_CHUNK_SIZE)) {
// if the block we are re-using is considerably larger (32 bytes)
// than what we request, then split it.
int old_size = block->size;
block->size = size;
// save next ptr
struct malloc_chunk *next = (struct malloc_chunk*) block->fd;
char* p = (char*) block;
p = p + (MALLOC_CHUNK_SIZE + size);
block->fd = (struct malloc_chunk*) p;
// point to next free byte
//(char*) block->fd = (char*) block + size + MALLOC_CHUNK_SIZE;
// create a new block header for the remainder of the block
struct malloc_chunk *split = (struct malloc_chunk*) block->fd;
split->size = old_size - MALLOC_CHUNK_SIZE - size;
split->is_free = 1;
split->fd = next;
}
*/
block->is_free = 0;
}
}
return(block+1);
}
void *myallocate_self(int size)
{
struct block_meta *block;
struct block_meta *last = global_base;
if (!global_base)
{ // First call.
block = request_space(NULL, size);
if (!block)
{
return NULL;
}
global_base = block;
}
else {
block = find_free_block(&last, size);
if (!block)
{ // Failed to find free block.
block = request_space(last, size);
if (!block)
{
return NULL;
}
}
else
{ // Found free block
// TODO: consider splitting block here.
block->free = 0;
}
}
return block;
}