Function realloc

Engine/source/platform/platformMemory.cpp:1464–1571

#if !defined(TORQUE_DISABLE_MEMORY_MANAGER)
static void* realloc(void* mem, dsize_t size, const char* fileName, const U32 line)
{
   //validate();
   if (!size) {
      free(mem, false);
      return NULL;
   }
   if(!mem)
      return alloc(size, false, fileName, line);

#ifdef TORQUE_MULTITHREAD
   if(!gMemMutex)
      gMemMutex = Mutex::createMutex();

   Mutex::lockMutex(gMemMutex);
#endif

   AllocatedHeader* hdr = ((AllocatedHeader *)mem) - 1;
#ifdef TORQUE_DEBUG_GUARD
   checkGuard( ( Header* ) hdr, true );
#endif

   AssertFatal((hdr->flags & Allocated) == Allocated, "Bad block flags.");

   size = (size + 0xF) & ~0xF;

   U32 oldSize = hdr->size;
   if(oldSize == size)
   {
#ifdef TORQUE_MULTITHREAD
      Mutex::unlockMutex(gMemMutex);
#endif
      return mem;
   }
   PROFILE_START(MemoryRealloc);

   FreeHeader *next = (FreeHeader *) hdr->next;

#ifdef TORQUE_DEBUG_GUARD
   // adjust header size and allocated bytes size
   hdr->realSize   += size - oldSize;
   gBytesAllocated += size - oldSize;
   if (gEnableLogging)
      logRealloc(hdr, size);

   // Add reallocated flag, note header changes will not persist if the realloc 
   // decides tofree, and then perform a fresh allocation for the memory. The flag will 
   // be manually set again after this takes place, down at the bottom of this fxn.
   hdr->flags |= Reallocated;

   // Note on Above ^
   // A more useful/robust implementation can be accomplished by storing an additional
   // AllocatedHeader* in DEBUG_GUARD builds inside the AllocatedHeader structure
   // itself to create a sort of reallocation history. This will be, essentially,
   // a allocation header stack for each allocation. Each time the memory is reallocated
   // it should use dRealMalloc (IMPORTANT!!) to allocate a AllocatedHeader* and chain
   // it to the reallocation history chain, and the dump output changed to display
   // reallocation history. It is also important to clean up this chain during 'free'