Class StableManager

java.lang.Object
gnu.lists.StableManager
public class StableManager extends Object
Implements a stable sequence with sticky positions. I.e if you have a position, it gets automatically updated after insertions and deletions.

  • Field Details

    • positions

      protected int[] positions
      This array maps from the exported ipos values (indexes in the positions array) to the ipos of the underlying SimpleVector base. The first two elements are reserved for START_POSITION and END_POSITION. Unused elements in positions are chained together in a free list headed by the 'free' variable.

    • free

      protected int free
      The head of the free elements in position, if they are chained. We keep track of available elements in the positions array in two ways: In unchained mode, there is no free list per se. Instead an index i is available if positions[i]==FREE_POSITION. This mode makes it easy to loop over all positions, ignoring the unused ones. In chained mode, there is a free list and if index i is available, then positions[i] is the next available index, with -1 if there is none. Unchained mode is indicated by free==-2. In chained mode, free is the first element in the free list, or -1 if the free list is empty. The main virtue of this convention is that we don't need a separate list or array for the free list. But we should get rid of the unchained mode, at least. FIXME.

    • FREE_POSITION

      protected static final int FREE_POSITION
      An invalid value for an in-use element of positions.
      See Also:

  • Constructor Details

  • Method Details

    • chainFreelist

      protected void chainFreelist()
      Put all free elements in positions in a chain starting with free.

    • unchainFreelist

      protected void unchainFreelist()
      Set all free elements in positions to FREE_POSITION.

    • startPos

      public int startPos()

    • endPos

      public int endPos()

    • allocPositionIndex

      protected int allocPositionIndex()

    • createPos

      public int createPos(int index, boolean isAfter)

    • isAfterPos

      protected boolean isAfterPos(int ipos)

    • hasNext

      public boolean hasNext(int ipos)

    • nextPos

      public int nextPos(int ipos)

    • nextIndex

      public int nextIndex(int ipos)

    • releasePos

      public void releasePos(int ipos)

    • copyPos

      public int copyPos(int ipos)

    • gapReserve

      protected void gapReserve(SimpleVector base, int where, int needed)
      Adjust gap to 'where', and make sure it is least `needed' elements long.

    • adjustPositions

      protected void adjustPositions(int low, int high, int delta)
      Add a delta to all positions elements that point into a given range. Assume x==positions[i], then if (unsigned)x>=(unsigned)low && (unsigned)x <= (unsigned)high, then add delta to positions[i]. Using unsigned comparisons allows us to compare ipos values, which include both the index and the isAfter low-order bit.

    • removePosRange

      protected void removePosRange(int ipos0, int ipos1)

    • consumePosRange

      public void consumePosRange(int iposStart, int iposEnd, Consumer out)