Function handmade_aligned_realloc

Eigen/src/Core/util/Memory.h:106–120

\internal * \brief Reallocates aligned memory. * Since we know that our handmade version is based on std::malloc * we can use std::realloc to implement efficient reallocation. */

  * we can use std::realloc to implement efficient reallocation.
  */
inline void* handmade_aligned_realloc(void* ptr, std::size_t size, std::size_t = 0)
{
  if (ptr == 0) return handmade_aligned_malloc(size);
  void *original = *(reinterpret_cast<void**>(ptr) - 1);
  std::ptrdiff_t previous_offset = static_cast<char *>(ptr)-static_cast<char *>(original);
  original = std::realloc(original,size+EIGEN_DEFAULT_ALIGN_BYTES);
  if (original == 0) return 0;
  void *aligned = reinterpret_cast<void*>((reinterpret_cast<std::size_t>(original) & ~(std::size_t(EIGEN_DEFAULT_ALIGN_BYTES-1))) + EIGEN_DEFAULT_ALIGN_BYTES);
  void *previous_aligned = static_cast<char *>(original)+previous_offset;
  if(aligned!=previous_aligned)
    std::memmove(aligned, previous_aligned, size);
  
  *(reinterpret_cast<void**>(aligned) - 1) = original;
  return aligned;
}

/*****************************************************************************
*** Implementation of portable aligned versions of malloc/free/realloc     ***