Function emmalloc_aligned_realloc_uninitialized

system/lib/emmalloc.c:1083–1117

emmalloc_aligned_realloc_uninitialized() is like aligned_realloc(), but old memory contents will be undefined after reallocation. (old memory is not preserved in any case)

// emmalloc_aligned_realloc_uninitialized() is like aligned_realloc(), but old memory contents
// will be undefined after reallocation. (old memory is not preserved in any case)
void *emmalloc_aligned_realloc_uninitialized(void *ptr, size_t alignment, size_t size) {
  if (!ptr) {
    return emmalloc_memalign(alignment, size);
  }

  if (size == 0) {
    free(ptr);
    return 0;
  }

  if (size > MAX_ALLOC_SIZE) {
#ifdef EMMALLOC_VERBOSE
    MAIN_THREAD_ASYNC_EM_ASM(out('Allocation failed: attempted allocation size is too large: ' + Number($0) + 'bytes! (negative integer wraparound?)'), size);
#endif
    return 0;
  }

  size = validate_alloc_size(size);

  // Calculate the region start address of the original allocation
  Region *region = (Region*)((uint8_t*)ptr - sizeof(size_t));

  // First attempt to resize the given region to avoid having to copy memory around
  if (acquire_and_attempt_region_resize(region, size + REGION_HEADER_SIZE)) {
#ifdef __EMSCRIPTEN_TRACING__
    emscripten_trace_record_reallocation(ptr, ptr, size);
#endif
    return ptr;
  }

  // If resize failed, drop the old region and allocate a new region. Memory is not
  // copied over
  free(ptr);
  return emmalloc_memalign(alignment, size);
}

void *emmalloc_realloc(void *ptr, size_t size) {
  return emmalloc_aligned_realloc(ptr, MALLOC_ALIGNMENT, size);