dmmlib/custom_malloc.c

#include "custom_malloc.h"
#ifdef HAVE_LOCKS
#include "posix_lock.h"
#endif /* HAVE_LOCKS */
#include "other.h"
#include "sys_alloc.h"
#include "block_header.h"
#include "dmm_adaptor.h"

void * custom_malloc(heap_t* heap, size_t size) {
    void *ptr;
    int fixed_list_id, i;
    maptable_node_t *current_maptable_node;
    void *current_block, *previous_block;

    ptr = NULL;
    previous_block = NULL;

#ifdef HAVE_LOCKS
    posix_lock(heap);
#endif /* HAVE_LOCKS */

    fixed_list_id = map_size_to_list(heap, req_padding(size));

    // If a fixed list is found, do a first fit
    if(fixed_list_id != -1) {
        current_maptable_node = heap->maptable_head;
        // traverse through the maptable node list
        if(fixed_list_id != 0) {
            for(i = 1; i < fixed_list_id; i++) {
                current_maptable_node = current_maptable_node->next;
            }
        }
        if(current_maptable_node->fixed_list_head != NULL) {
            ptr = current_maptable_node->fixed_list_head;
            current_maptable_node->fixed_list_head = get_next(ptr);
        }
    }

    if(ptr == NULL) {

        // first fit from free list
        for(current_block = heap->free_list_head; current_block != NULL;
                current_block = get_next(current_block)) {
            if(get_size(current_block) >= size) {
                if(current_block == heap->free_list_head) {
                    heap->free_list_head = get_next(ptr);
                } else {
                    set_next(previous_block, get_next(current_block));
                }
                ptr = current_block;
                break;
            }
            previous_block = current_block;
        }
    }

    if(ptr == NULL) {
        ptr = sys_alloc(heap, size);
    }

    set_requested_size(ptr, size);
    set_next(ptr, heap->used_blocks_head);

    heap->used_blocks_head = ptr;

    // Begin of Stats

    heap->dmm_stats.live_objects += 1;
    heap->dmm_stats.num_malloc += 1;

    // End of Stats

    // Refresh the state of the heap allocator if a certain number of
    // malloc's has been served already
    // TODO Define 50 as a constant
    if(heap->dmm_stats.num_malloc % 50) {
        state_refresh(heap);
    }

#ifdef HAVE_LOCKS
    posix_unlock(heap);
#endif /* HAVE_LOCKS */
    return ptr;
}