memory arena sample

// A arena might look like:

struct Arena {
    void * ptr;
    size_t total_size;
    size_t filled_size;
    Arena *next;
    Arena *prev;
}

// malloc() would be implemented like:

void* malloc (Arena *a, size_t s)
{
    if (a->filled_size + s > a->total_size) { // arena is full
        // allocate new arena
        // insert it in the linked list
        // blah blah
    }

    void *result = a->ptr;
    a->ptr += s;
    a->filled_size += s;

    return result;
}