static long[] longArrayFromBytes(byte[] a) {
  ret longArrayFromBytes(a, 0, l(a));
}

static long[] longArrayFromBytes(byte[] a, int from, int to) {
  long[] b = new[(to-from)/8];
  for (int i = 0; i < b.length; i++)
    b[i] = longFromBytes_bigEndian(a, from+i*8);
  ret b;
}

Began life as a copy of #1007028