dbcsr_mempool_get Function

   FUNCTION dbcsr_mempool_get(memtype, datatype, datasize) RESULT(res)
      !! Picks a suitable data_area from mempool, returns Null() if none found.
      TYPE(dbcsr_memtype_type)                           :: memtype
      INTEGER, INTENT(IN)                                :: datatype, datasize
      TYPE(dbcsr_data_obj)                               :: res

      INTEGER                                            :: best_size, s
      TYPE(dbcsr_mempool_entry_type), POINTER            :: best_cur, best_prev, cur, prev
      TYPE(dbcsr_mempool_type), POINTER                  :: pool

      pool => memtype%pool
      IF (.NOT. ASSOCIATED(pool)) DBCSR_ABORT("pool not allocated")

!$    CALL OMP_SET_LOCK(pool%lock)
      res%d => Null()
      best_cur => Null()
      best_prev => Null()
      best_size = HUGE(1)
      prev => Null()
      cur => pool%root
      DO WHILE (ASSOCIATED(cur%next))
         prev => cur
         cur => cur%next
         s = dbcsr_data_get_size(cur%area)
         IF (s < datasize) CYCLE
         IF (.NOT. dbcsr_memtype_equal(cur%area%d%memory_type, memtype)) CYCLE
         IF (cur%area%d%data_type /= datatype) CYCLE
         !we found a match
         IF (s < best_size) THEN
            best_cur => cur
            best_prev => prev
            best_size = s
         END IF
      END DO

      IF (ASSOCIATED(best_cur)) THEN
         IF (best_cur%area%d%refcount /= 0) DBCSR_ABORT("refcount /= 0")
         best_cur%area%d%refcount = 1
         best_prev%next => best_cur%next
         res = best_cur%area
         DEALLOCATE (best_cur)
      END IF
!$    CALL OMP_UNSET_LOCK(pool%lock)

      IF (.NOT. ASSOCIATED(res%d)) &
         CALL mempool_collect_garbage(pool)
   END FUNCTION dbcsr_mempool_get