code: private int ssCompare(int pa, int pb, int p2, int depth) {
          int U1, U2, U1n, U2n;// pointers to T
  
          for (U1 = depth + pa, U2 = depth + SA[p2], U1n = pb + 2, U2n = SA[p2 + 1] + 2; (U1 < U1n)
              && (U2 < U2n) && (T[start + U1] == T[start + U2]); ++U1, ++U2) {
          }
  
          return U1 < U1n ? (U2 < U2n ? T[start + U1] - T[start + U2] : 1) : (U2 < U2n ? -1
              : 0);
      }
docs: special version of ss_compare for handling
  <code>ss_compare(T, &(PAi[0]), PA + *a, depth)</code> situation.