- added methods 'equals' and 'toString'.

1 files changed, 44 insertions, 3 deletions

diff --git a/sources/scala/collection/BitSet.scala b/sources/scala/collection/BitSet.scala
index 522b93bf2a..55162c4022 100644
--- a/sources/scala/collection/BitSet.scala
+++ b/sources/scala/collection/BitSet.scala
@@ -11,7 +11,7 @@ package scala.collection;
 
 /** The class <code>BitSet</code> ...
  *
- *  @author  Burak Emir
+ *  @author  Burak Emir, Stephane Micheloud
  *  @version 1.0
  */
 abstract class BitSet with Function1[Int,Boolean] {
@@ -29,8 +29,9 @@ abstract class BitSet with Function1[Int,Boolean] {
     def next: Boolean = { i = i + 1; apply(i-1) }
   }
 
-  /** returns the subset of <code>[0..size]</code> whose elements are
-   *  indices of bits set to <code>v</code>.
+  /**
+   * Returns the subset of <code>[0..size]</code> whose elements are
+   * indices of bits set to <code>v</code>.
    *
    *  @param v
    */
@@ -45,4 +46,44 @@ abstract class BitSet with Function1[Int,Boolean] {
     res
   }
 
+  /**
+   * Checks if two bitsets are structurally identical.
+   *
+   *  @return true, iff both bitsets contain the same sequence of elements.
+   */
+  override def equals(that: Any): Boolean =
+    that.isInstanceOf[BitSet] &&
+    { val other = that.asInstanceOf[BitSet];
+      (size == other.size) &&
+      (Iterator.range(0, size) forall { i => apply(i) == other.apply(i)});
+    };
+
+  /**
+   * Returns a string representation of this bitset in hexadecimal form,
+   * e.g. the bitset 001000001100 (12 bits) is represented as "20c" and
+   * the bitset 00100000110 (11 bits) as "106".
+   *
+   * @return the string representation for this bitset
+   */
+  override def toString() = {
+    val sb = new StringBuffer();
+    val n = size % 4;
+    if (n > 0) {
+      val x = (if (apply(0))          4 else 0)
+            + (if (n > 1 && apply(1)) 2 else 0)
+            + (if (n > 2 && apply(2)) 1 else 0);
+      sb.append(Integer.toHexString(x));
+    }
+    var i = n;
+    while (i < size) {
+      val x = (if (apply(i))   8 else 0)
+            + (if (apply(i+1)) 4 else 0)
+            + (if (apply(i+2)) 2 else 0)
+            + (if (apply(i+3)) 1 else 0);
+      sb.append(Integer.toHexString(x));
+      i = i + 4
+    }
+    sb.toString()
+  }
+
 }