Function emmalloc_aligned_realloc

system/lib/emmalloc.c:995–1042

}

void *emmalloc_aligned_realloc(void *ptr, size_t alignment, size_t size) {
#ifdef EMMALLOC_VERBOSE
  MAIN_THREAD_ASYNC_EM_ASM(out('aligned_realloc(ptr=' + ptrToString($0) + ', alignment=' + $1 + ', size=' + Number($2)), ptr, alignment, size);
#endif

  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;
  }

  assert(IS_POWER_OF_2(alignment));
  // aligned_realloc() cannot be used to ask to change the alignment of a pointer.
  assert(HAS_ALIGNMENT(ptr, alignment));
  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, we must allocate a new region, copy the data over, and then
  // free the old region.
  void *newptr = emmalloc_memalign(alignment, size);
  if (newptr) {
    memcpy(newptr, ptr, MIN(size, region->size - REGION_HEADER_SIZE));
    free(ptr);
  }
  // N.B. If there is not enough memory, the old memory block should not be freed and
  // null pointer is returned.
  return newptr;
}
EMMALLOC_ALIAS(aligned_realloc, emmalloc_aligned_realloc);

// realloc_try() is like realloc(), but only attempts to try to resize the existing memory