FreeZone.java

package jetbrains.mps.ide.dataFlow.presentation;

/*Generated by MPS */


public class FreeZone {
  private FreeZone myNext;
  private FreeZone myPrev;
  private int myFirstIndex;
  private int myLastIndex;
  private boolean myIsDeleted = false;
  public FreeZone(int firstIndex, int lastIndex) {
    this.myFirstIndex = firstIndex;
    this.myLastIndex = lastIndex;
  }
  public boolean insert(int first, int last) {
    if (this.myIsDeleted) {
      return false;
    }
    if (first < this.myFirstIndex) {
      return false;
    }
    if (last > this.myLastIndex) {
      return false;
    }
    FreeZone before;
    FreeZone after;
    int wasFirstIndex = this.myFirstIndex;
    int wasLastIndex = this.myLastIndex;
    if (this.myPrev == null) {
      before = this;
    } else {
      before = new FreeZone(-1, -1);
      before.myNext = this;
      before.myPrev = this.myPrev;
      if (this.myPrev != null) {
        this.myPrev.myNext = before;
      }
      this.myPrev = before;
    }
    before.myFirstIndex = wasFirstIndex;
    before.myLastIndex = first - 1;
    if (first == wasFirstIndex) {
      before.delete();
    }
    if (this.myNext == null && before != this) {
      after = this;
    } else {
      after = new FreeZone(-1, -1);
      after.myPrev = this;
      after.myNext = this.myNext;
      if (this.myNext != null) {
        this.myNext.myPrev = after;
      }
      this.myNext = after;
    }
    after.myFirstIndex = last + 1;
    after.myLastIndex = wasLastIndex;
    if (last == wasLastIndex) {
      after.delete();
    }
    return true;
  }
  public boolean canBeAdded(int first, int last) {
    FreeZone current = this;
    while (current != null) {
      if (current.insert(first, last)) {
        return true;
      }
      current = current.myNext;
    }
    return false;
  }
  private void delete() {
    if (this.myPrev != null) {
      this.myPrev.myNext = this.myNext;
    }
    if (this.myNext != null) {
      this.myNext.myPrev = this.myPrev;
    }
    this.myIsDeleted = true;
  }
}