Function pffft_aligned_malloc

OOps/pffft.c:259–265

/* SSE and co like 16-bytes aligned pointers */
#define MALLOC_V4SF_ALIGNMENT 64 // with a 64-byte alignment, we are even aligned on L2 cache lines...
void *pffft_aligned_malloc(size_t nb_bytes) {
  void *p, *p0 = malloc(nb_bytes + MALLOC_V4SF_ALIGNMENT);
  if (!p0) return (void *) 0;
  p = (void *) (((size_t) p0 + MALLOC_V4SF_ALIGNMENT) & (~((size_t) (MALLOC_V4SF_ALIGNMENT-1))));
  *((void **) p - 1) = p0;
  return p;
}

void pffft_aligned_free(void *p) {
  if (p) free(*((void **) p - 1));