/* malloc_quick
*
* malloc_quick returns the start address of the newly allocated memory.
*
*/
void *malloc_quick(
size_t nbytes) /* number of bytes of memory to allocate */
{
Header *moreroce(unsigned);
int list_index, i;
list_index = get_quick_fit_list_index(nbytes);
/*
* Use another strategy for too large allocations. We want the allocation
* to be quick, so use malloc_first().
*/
if (list_index >= NRQUICKLISTS) {
return malloc_first(nbytes);
}
/*
* Initialize the quick fit lists if this is the first run.
*/
if (first_run) {
for (i = 0; i < NRQUICKLISTS; ++i) {
quick_fit_lists[i] = NULL;
}
first_run = false;
}
/*
* If the quick fit list pointer is NULL, then there are no free memory
* blocks present, so we will have to create some before continuing.
*/
if (quick_fit_lists[list_index] == NULL) {
Header* new_quick_fit_list = init_quick_fit_list(list_index);
if (new_quick_fit_list == NULL) {
return NULL;
} else {
quick_fit_lists[list_index] = new_quick_fit_list;
}
}
/*
* Now that we know there is at least one free quick fit memory block,
* let's use return that and also update the quick fit list pointer so that
* it points to the next in the list.
*/
void* pointer_to_return = (void *)(quick_fit_lists[list_index] + 1);
quick_fit_lists[list_index] = quick_fit_lists[list_index]->s.ptr;
return pointer_to_return;
}
/* number of bytes of memory to allocate */
void *malloc(size_t nbytes) {
if (nbytes == 0) {
return NULL;
}
#if STRATEGY == 1
return malloc_first(nbytes);
#elif STRATEGY == 2
return malloc_best(nbytes);
#elif STRATEGY == 3
return malloc_worst(nbytes);
#elif STRATEGY == 4
return malloc_quick(nbytes);
#else
exit(1);
#endif
}
/* malloc
*
* malloc returns the start address of dynamically allocated memory.
* This is simply a wrapper function that calls the different algorithm
* implementations depending on the value of STRATEGY.
*
*/
void *malloc(
size_t nbytes) /* number of bytes of memory to allocate */
{
if (nbytes == 0) {
return NULL;
}
#if STRATEGY == 1
return malloc_first(nbytes);
#elif STRATEGY == 2
return malloc_best(nbytes);
#elif STRATEGY == 3
return malloc_worst(nbytes);
#elif STRATEGY == 4
return malloc_quick(nbytes);
#else
exit(1);
#endif
}
