C    Copyright(C) 1999-2020 National Technology & Engineering Solutions
C    of Sandia, LLC (NTESS).  Under the terms of Contract DE-NA0003525 with
C    NTESS, the U.S. Government retains certain rights in this software.
C
C    See packages/seacas/LICENSE for details

      SUBROUTINE LTADD (MDIM, MDIMO, N, LINK, IHOLD)
C***********************************************************************

C  SUBROUTINE LTADD = LOOKUP TABLE REINSURTION FOR DATA POINTER ARRAYS

C***********************************************************************

C  VARIABLES USED:
C     MDIM   = DIMENSION OF LINK ARRAY, AND BASE FOR LOOKUP START
C     LINK   = LOOKUP TABLE ARRAY OF ID'S AND POINTERS
C              LINK(1,I) = ID VALUE STORED IN I'TH ROW (0 IF EMPTY)
C              LINK(2,I) = DATA POINTER ASSOCIATED W/THIS I'TH ID VALUE
C     IHOLD  = TEMPORARY LINK ARRAY TO BE USED FOR REINSURRTION

C***********************************************************************

      DIMENSION LINK(2,MDIM), IHOLD(2,MDIM)

      LOGICAL ADDLNK

      ADDLNK=.TRUE.

C  SORT THROUGH THE ORIGINAL LINK LIST AND LINK VALID ENTRIES IN THE
C  IHOLD LIST

      DO 100 I = 1, MDIMO
         IF ( (LINK(1,I) .NE. 0) .AND. (LINK(2,I) .LE. N) )
     &      CALL LTSORT (MDIM, IHOLD, IABS(LINK(1,I)), LINK(2,I),
     &      ADDLNK)
  100 CONTINUE

C  TRANSFER THE IHOLD LIST BACK TO THE LINK LIST

      DO 120 I = 1, MDIM
         DO 110 J = 1, 2
            LINK(J,I) = IHOLD (J, I)
  110    CONTINUE
  120 CONTINUE

      RETURN

      END