Initial revision

git-svn-id: https://svn.code.sf.net/p/jode/code/trunk@950 379699f6-c40d-0410-875b-85095c16579e
25 years ago · 610bc2106e
parent 97ff053675
commit 610bc2106e
1 changed files with 581 additions and 0 deletions
--- a/jode/jode/util/LinkedList.java
+++ b/jode/jode/util/LinkedList.java
@ -0,0 +1,581 @@
+// This class is taken from the Classpath project.  
+// Please note the different copyright holder!  
+// The changes I did is this comment, the package line, some
+// imports from java.util and some minor jdk12 -> jdk11 fixes.
+// -- Jochen Hoenicke <jochen@gnu.org>
+
+/////////////////////////////////////////////////////////////////////////////
+// LinkedList.java -- Linked list implementation of the List interface
+//
+// Copyright (c) 1998 by Stuart Ballard (stuart.ballard@mcmail.com)
+//
+// This program is free software; you can redistribute it and/or modify
+// it under the terms of the GNU Library General Public License as published
+// by the Free Software Foundation, version 2. (see COPYING.LIB)
+//
+// This program is distributed in the hope that it will be useful, but
+// WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Library General Public License for more details.
+//
+// You should have received a copy of the GNU Library General Public License
+// along with this program; if not, write to the Free Software Foundation
+// Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307 USA
+/////////////////////////////////////////////////////////////////////////////
+
+package jode.util;
+import java.util.NoSuchElementException;
+import java.io.Serializable;
+import java.io.ObjectOutputStream;
+import java.io.ObjectInputStream;
+import java.io.IOException;
+
+// TO DO:
+// ~ Doc comment for the class.
+// ~ Doc comments for the non-list methods.
+// ~ Some commenting on the Backing API and other general implementation notes.
+
+/**
+ * Linked list implementation of the List interface.
+ */
+public class LinkedList extends AbstractSequentialList 
+  implements Serializable, Cloneable
+{
+  static final long serialVersionUID = 876323262645176354L;
+
+  /**
+   * An Entry containing the head (in the next field) and the tail (in the
+   * previous field) of the list. The data field is null. If the list is empty,
+   * both the head and the tail point to ends itself.
+   */
+  transient Entry ends = new Entry();
+
+  /**
+   * The current length of the list.
+   */
+  transient int size = 0;
+
+  /**
+   * Class to represent an entry in the list. Holds a single element.
+   */
+  private static class Entry {
+
+    /**
+     * The list element.
+     */
+    Object data = null;
+
+    /**
+     * The next entry in the list. If this is the last entry in the list, the
+     * ends field of the list is held here.
+     */
+    Entry next;
+
+    /**
+     * The previous entry in the list. If this is the first entry in the list,
+     * the ends field of the list is held here.
+     */
+    Entry previous;
+
+    /**
+     * Create an entry with given data and linkage.
+     */
+    Entry(Object d, Entry n, Entry p) {
+      data = d;
+      next = n;
+      previous = p;
+    }
+
+    /**
+     * Create an entry with no data and linking to itself, for use as the ends
+     * field of the list.
+     */
+    Entry() {
+      next = previous = this;
+    }
+
+    /**
+     * Remove this entry.
+     */
+    Object remove() {
+      previous.next = next;
+      next.previous = previous;
+      return data;
+    }
+  }
+
+  private static interface Backing {
+    void checkMod(int known);
+    void upMod();
+    void incSize(int by);
+    void decSize(int by);
+  }
+
+  private final Backing back = new Backing() {
+    public void checkMod(int known) {
+      if (known != modCount) {
+	throw new ConcurrentModificationException();
+      }
+    }
+    public void upMod() {
+      modCount++;
+    }
+    public void incSize(int by) {
+      size += by;
+    }
+    public void decSize(int by) {
+      size -= by;
+    }
+  };
+
+  /** A ListIterator over the list. This class keeps track of its
+   * position in the list, the size of the list, and the two list
+   * entries it is between.  This enables it to be used identically
+   * for both the list itself and a sublist of the list.
+   */
+  private static class Iter implements ListIterator {
+
+    /**
+     * The index of the element that will be returned by next().
+     */
+    int pos;
+
+    /**
+     * The size of the backing list.
+     */
+    int size;
+
+    /**
+     * The entry containing the element that will be returned by next().
+     */
+    Entry next;
+
+    /**
+     * The entry containing the element that will be returned by previous().
+     */
+    Entry previous;
+
+    /**
+     * The entry that will be affected by remove() or set().
+     */
+    Entry recent;
+
+    /**
+     * The known value of the modCount of the backing list.
+     */
+    int knownMod;
+
+    private final Backing b;
+
+    /**
+     * Create a new Iter starting at a given Entry within the list, at a given
+     * position, in a list of given size.
+     *
+     * @param index the index to begin iteration.
+     * @exception IndexOutOfBoundsException if index < 0 || index > size.
+     */
+    Iter(Backing backing, Entry n, int index, int s, int mc) {
+      b = backing;
+      pos = index;
+      size = s;
+      next = n;
+      previous = n.previous;
+      knownMod = mc;
+    }
+
+    public int nextIndex() {
+      b.checkMod(knownMod);
+      return pos;
+    }
+
+    public int previousIndex() {
+      b.checkMod(knownMod);
+      return pos - 1;
+    }
+
+    public boolean hasNext() {
+      b.checkMod(knownMod);
+      return pos < size;
+    }
+
+    public boolean hasPrevious() {
+      b.checkMod(knownMod);
+      return pos > 0;
+    }
+
+    public Object next() {
+      b.checkMod(knownMod);
+      if (pos >= size) {
+	throw new NoSuchElementException();
+      } else {
+	pos++;
+	recent = previous = next;
+	next = recent.next;
+	return recent.data;
+      }
+    }
+
+    public Object previous() {
+      b.checkMod(knownMod);
+      if (pos <= 0) {
+	throw new NoSuchElementException();
+      } else {
+	pos--;
+	recent = next = previous;
+	previous = recent.previous;
+	return recent.data;
+      }
+    }
+
+    public void remove() {
+      b.checkMod(knownMod);
+      if (recent == null) {
+	throw new IllegalStateException();
+      }
+
+      // Adjust the position to before the removed element
+      if (recent == previous) pos--;
+
+      // Could use recent.remove() but this way is quicker, and also correctly
+      // fixes next and previous.
+      next = recent.previous.next = recent.next;
+      previous = recent.next.previous = recent.previous;
+      size--;
+      b.decSize(1);
+      knownMod++;
+      b.upMod();
+      recent = null;
+    }
+
+    public void add(Object o) {
+      b.checkMod(knownMod);
+      previous.next = next.previous = new Entry(o, next, previous);
+
+      // New for 1.2RC1 - the semantics changed so that the iterator is
+      // positioned *after* the new element.
+      previous = next;
+      next = previous.next;
+      pos++;
+
+      size++;
+      b.incSize(1);
+      knownMod++;
+      b.upMod();
+      recent = null;
+    }
+
+    public void set(Object o) {
+      b.checkMod(knownMod);
+      if (recent == null) {
+	throw new IllegalStateException();
+      }
+      recent.data = o;
+    }
+  }
+
+  /**
+   * Obtain the Entry at a given position in a list. This method of course
+   * takes linear time, but it is intelligent enough to take the shorter of the
+   * paths to get to the Entry required. This implies that the first or last
+   * entry in the list is obtained in constant time, which is a very desirable
+   * property.
+   * For speed and flexibility in which ranges are valid, range checking is not
+   * done in this method, and if n is outside the range -1 <= n <= size, the
+   * result will be wrong (but no exception will be thrown).
+   * Note that you *can* obtain entries at position -1 and size, which are
+   * equal to prehead and posttail respectively.
+   * This method is static so that it can also be used in subList.
+   *
+   * @param n the number of the entry to get.
+   * @param size the size of the list to get the entry in.
+   * @param head the entry before the first element of the list (usually ends).
+   * @param tail the entry after the last element of the list (usually ends).
+   */
+  static Entry getEntry(int n, int size, Entry head, Entry tail) {
+
+    // n less than size/2, iterate from start
+    if (n < size >> 1) {
+      while (n-- >= 0) {
+	head = head.next;
+      }
+      return head;
+
+    // n greater than size/2, iterate from end
+    } else {
+      while (++n <= size) {
+	tail = tail.previous;
+      }
+      return tail;
+    }
+  }
+
+  /**
+   * Create an empty linked list.
+   */
+  public LinkedList() {
+    super();
+  }
+
+  /**
+   * Create a linked list containing the elements, in order, of a given
+   * collection.
+   *
+   * @param c the collection to populate this list from.
+   */
+  public LinkedList(Collection c) {
+    super();
+    // Note: addAll could be made slightly faster, but not enough so to justify
+    // re-implementing it from scratch. It is just a matter of a relatively
+    // small constant factor.
+    addAll(c);
+  }
+
+  public Object getFirst() {
+    if (size == 0) {
+      throw new NoSuchElementException();
+    }
+    return ends.next.data;
+  }
+
+  public Object getLast() {
+    if (size == 0) {
+      throw new NoSuchElementException();
+    }
+    return ends.previous.data;
+  }
+
+  public Object removeFirst() {
+    if (size == 0) {
+      throw new NoSuchElementException();
+    }
+    size--;
+    modCount++;
+    return ends.next.remove();
+  }
+
+  public Object removeLast() {
+    if (size == 0) {
+      throw new NoSuchElementException();
+    }
+    size--;
+    modCount++;
+    return ends.previous.remove();
+  }
+
+  public void addFirst(Object o) {
+    ends.next.previous = ends.next = new Entry(o, ends.next, ends);
+    size++;
+    modCount++;
+  }
+
+  public void addLast(Object o) {
+    ends.previous.next = ends.previous = new Entry(o, ends, ends.previous);
+    size++;
+    modCount++;
+  }
+
+  /**
+   * Obtain the number of elements currently in this list.
+   *
+   * @returns the number of elements currently in this list.
+   */
+  public int size() {
+    return size;
+  }
+
+  /**
+   * Remove a range of elements from this list.
+   *
+   * @param fromIndex the index, inclusive, to remove from.
+   * @param toIndex the index, exclusive, to remove to.
+   * @exception IndexOutOfBoundsException if fromIndex > toIndex || fromIndex <
+   *   0 || toIndex > size().
+   */
+  // Note: normally removeRange is provided to allow efficient ways to
+  // implement clear() on subLists. However, in this case clear on subLists
+  // works anyway, so this implementation is included just for completeness
+  // and because subclasses might try to use it.
+  protected void removeRange(int fromIndex, int toIndex) {
+    subList(fromIndex, toIndex).clear();
+  }
+
+  /**
+   * Clear the list.
+   */
+  public void clear() {
+    ends.next = ends.previous = ends;
+    modCount++;
+    size = 0;
+  }
+
+  /**
+   * Obtain a ListIterator over this list, starting at a given index. The
+   * ListIterator returned by this method supports the add, remove and set
+   * methods.
+   *
+   * @param index the index of the element to be returned by the first call to
+   *   next(), or size() to be initially positioned at the end of the list.
+   * @exception IndexOutOfBoundsException if index < 0 || index > size().
+   */
+  public ListIterator listIterator(int index) {
+
+    // Check bounds
+    if (index < 0 || index > size) {
+      throw new IndexOutOfBoundsException();
+    }
+
+    return new Iter(back, getEntry(index, size, ends, ends), 
+		    index, size, modCount);
+  }
+
+  /**
+   * Obtain a List view of a subsection of this list, from fromIndex
+   * (inclusive) to toIndex (exclusive). The returned list is modifiable in
+   * every respect. Changes to the returned list are reflected in this list. If
+   * this list is structurally modified is any way other than through the
+   * returned list, any subsequent operations on the returned list will result
+   * in a ConcurrentModificationException (that is, the returned list is
+   * fail-fast).
+   *
+   * @param fromIndex the index that the returned list should start from
+   *    (inclusive).
+   * @param toIndex the index that the returned list should go to (exclusive).
+   * @returns a List backed by a subsection of this list.
+   * @exception IndexOutOfBoundsException if fromIndex < 0 || toIndex > size()
+   *   || fromIndex > toIndex.
+   */
+  public List subList(int fromIndex, int toIndex) {
+
+    // Check bounds
+    if (fromIndex > toIndex || fromIndex < 0 || toIndex > size) {
+      throw new IndexOutOfBoundsException();
+    }
+
+    return new SubLinkedList(back, getEntry(fromIndex - 1, size, ends, ends),
+			     getEntry(toIndex, size, ends, ends),
+			     toIndex - fromIndex);
+  }
+
+  private static class SubLinkedList extends AbstractSequentialList {
+
+    Entry head; // entry before the beginning
+    Entry tail; // entry after the end
+    int size;
+    private final Backing b;
+
+    private final Backing back = new Backing() {
+      public void checkMod(int known) {
+	if (known != modCount) {
+	  throw new ConcurrentModificationException();
+	}
+      }
+      public void upMod() {
+	modCount++;
+      }
+      public void incSize(int by) {
+	size += by;
+      }
+      public void decSize(int by) {
+	size -= by;
+      }
+    };
+
+    SubLinkedList(Backing backing, Entry h, Entry t, int s) {
+      b = backing;
+      head = h;
+      tail = t;
+      size = s;
+    }
+
+    public int size() {
+      b.checkMod(this.modCount);
+      return size;
+    }
+
+    public ListIterator listIterator(int index) {
+      b.checkMod(this.modCount);
+
+      // Check bounds
+      if (index < 0 || index > size) {
+	throw new IndexOutOfBoundsException();
+      }
+
+      return new Iter(back, getEntry(index, size, head, tail), 
+		      index, size, modCount);
+    }
+
+    public void clear() {
+      b.checkMod(this.modCount);
+      head.next = tail;
+      tail.previous = head;
+      size = 0;
+      b.decSize(size);
+      modCount++;
+      b.upMod();
+    }
+
+    // No removeRange because this class cannot be publically subclassed.
+
+    public List subList(int fromIndex, int toIndex) {
+      b.checkMod(this.modCount);
+
+      // Check bounds
+      if (fromIndex > toIndex || fromIndex < 0 || toIndex > size) {
+	throw new IndexOutOfBoundsException();
+      }
+
+      return new SubLinkedList(back, getEntry(fromIndex - 1, size, head, tail),
+			       getEntry(toIndex, size, head, tail),
+			       toIndex - fromIndex);
+    }
+  }
+
+  /**
+   * Create a shallow copy of this LinkedList.
+   * @return an object of the same class as this object, containing the
+   * same elements in the same order.
+   */
+  public Object clone() 
+  {
+    LinkedList copy;
+    try
+      {
+	copy = (LinkedList) super.clone();
+      }
+    catch (CloneNotSupportedException ex)
+      {
+	throw new InternalError(ex.getMessage());
+      }
+    copy.size = 0;
+    copy.ends = new Entry();
+    copy.addAll(this);
+    return copy;
+  }
+
+  /**
+   * Serialize an object to a stream.
+   * @serialdata the size of the list (int), followed by all the elements
+   * (Object) in proper order.
+   */
+  private void writeObject(ObjectOutputStream s)
+    throws IOException
+  {
+    s.writeInt(size);
+    for (Iterator i = iterator(); i.hasNext(); )
+      s.writeObject(i.next());
+  }
+
+  /**
+   * Deserialize an object from a stream.
+   * @serialdata the size of the list (int), followed by all the elements
+   * (Object) in proper order.
+   */
+  private void readObject(ObjectInputStream s)
+    throws IOException, ClassNotFoundException
+  {
+    int serialSize = s.readInt();
+    ends = new Entry();
+    for (int i=0; i< serialSize; i++)
+      addLast(s.readObject());
+  }
+}