ByteBuffer.java (hashCode): Implemented.

2004-09-21  Sven de Marothy <sven@physto.se>

	* java/nio/ByteBuffer.java (hashCode): Implemented.
	* java/nio/CharBuffer.java: Likewise.
	* java/nio/DoubleBuffer.java: Likewise.
	* java/nio/FloatBuffer.java: Likewise.
	* java/nio/LongBuffer.java: Likewise.
	* java/nio/IntBuffer.java: Likewise.
	* java/nio/ShortBuffer.java: Likewise.

From-SVN: r87804

7 files changed, 124 insertions, 14 deletions

diff --git a/libjava/java/nio/ByteBuffer.java b/libjava/java/nio/ByteBuffer.java
index 378e588..e502e00 100644
--- a/libjava/java/nio/ByteBuffer.java
+++ b/libjava/java/nio/ByteBuffer.java
@@ -260,11 +260,27 @@ public abstract class ByteBuffer extends Buffer
 
   /**
    * Calculates a hash code for this buffer.
+   *
+   * This is done with <code>int</code> arithmetic,
+   * where ** represents exponentiation, by this formula:<br>
+   * <code>s[position()] + 31 + (s[position()+1] + 30)*31**1 + ... +
+   * (s[limit()-1]+30)*31**(limit()-1)</code>.
+   * Where s is the buffer data. Note that the hashcode is dependent
+   * on buffer content, and therefore is not useful if the buffer
+   * content may change.
+   *
+   * @return the hash code
    */
   public int hashCode ()
   {
-    // FIXME: Check what SUN calculates here.
-    return super.hashCode ();
+    int hashCode = get(position()) + 31;
+    int multiplier = 1;
+    for (int i = position() + 1; i < limit(); ++i)
+      {
+	  multiplier *= 31;
+	  hashCode += (get(i) + 30)*multiplier;
+      }
+    return hashCode;
   }
 
   /**
diff --git a/libjava/java/nio/CharBuffer.java b/libjava/java/nio/CharBuffer.java
index 4ef257b..700c567 100644
--- a/libjava/java/nio/CharBuffer.java
+++ b/libjava/java/nio/CharBuffer.java
@@ -297,11 +297,25 @@ public abstract class CharBuffer extends Buffer
 
   /**
    * Calculates a hash code for this buffer.
+   *
+   * This is done with int arithmetic,
+   * where ** represents exponentiation, by this formula:<br>
+   * <code>s[position()] + 31 + (s[position()+1] + 30)*31**1 + ... +
+   * (s[limit()-1]+30)*31**(limit()-1)</code>.
+   * Where s is the buffer data. Note that the hashcode is dependent
+   * on buffer content, and therefore is not useful if the buffer
+   * content may change.
    */
   public int hashCode ()
   {
-    // FIXME: Check what SUN calculates here.
-    return super.hashCode ();
+    int hashCode = get(position()) + 31;
+    int multiplier = 1;
+    for (int i = position() + 1; i < limit(); ++i)
+      {
+	  multiplier *= 31;
+	  hashCode += (get(i) + 30)*multiplier;
+      }
+    return hashCode;
   }
 
   /**
diff --git a/libjava/java/nio/DoubleBuffer.java b/libjava/java/nio/DoubleBuffer.java
index 10055cd..dd16ee0 100644
--- a/libjava/java/nio/DoubleBuffer.java
+++ b/libjava/java/nio/DoubleBuffer.java
@@ -243,11 +243,27 @@ public abstract class DoubleBuffer extends Buffer
 
   /**
    * Calculates a hash code for this buffer.
+   *
+   * This is done with <code>long</code> arithmetic,
+   * where ** represents exponentiation, by this formula:<br>
+   * <code>s[position()] + 31 + (s[position()+1] + 30)*31**1 + ... +
+   * (s[limit()-1]+30)*31**(limit()-1)</code>.
+   * Where s is the buffer data, in Double.doubleToLongBits() form
+   * Note that the hashcode is dependent on buffer content, 
+   * and therefore is not useful if the buffer content may change.
+   *
+   * @return the hash code (casted to int)
    */
   public int hashCode ()
   {
-    // FIXME: Check what SUN calculates here.
-    return super.hashCode ();
+    long hashCode = Double.doubleToLongBits(get(position())) + 31;
+    long multiplier = 1;
+    for (int i = position() + 1; i < limit(); ++i)
+      {
+	  multiplier *= 31;
+	  hashCode += (Double.doubleToLongBits(get(i)) + 30)*multiplier;
+      }
+    return ((int)hashCode);
   }
 
   /**
diff --git a/libjava/java/nio/FloatBuffer.java b/libjava/java/nio/FloatBuffer.java
index 6d19503..2ead8cb 100644
--- a/libjava/java/nio/FloatBuffer.java
+++ b/libjava/java/nio/FloatBuffer.java
@@ -243,11 +243,27 @@ public abstract class FloatBuffer extends Buffer
 
   /**
    * Calculates a hash code for this buffer.
+   *
+   * This is done with <code>int</code> arithmetic,
+   * where ** represents exponentiation, by this formula:<br>
+   * <code>s[position()] + 31 + (s[position()+1] + 30)*31**1 + ... +
+   * (s[limit()-1]+30)*31**(limit()-1)</code>.
+   * Where s is the buffer data, in Float.floatToIntBits() form
+   * Note that the hashcode is dependent on buffer content, 
+   * and therefore is not useful if the buffer content may change.
+   *
+   * @return the hash code
    */
   public int hashCode ()
   {
-    // FIXME: Check what SUN calculates here.
-    return super.hashCode ();
+    int hashCode = Float.floatToIntBits(get(position())) + 31;
+    int multiplier = 1;
+    for (int i = position() + 1; i < limit(); ++i)
+      {
+	  multiplier *= 31;
+	  hashCode += (Float.floatToIntBits(get(i)) + 30)*multiplier;
+      }
+    return hashCode;
   }
 
   /**
diff --git a/libjava/java/nio/IntBuffer.java b/libjava/java/nio/IntBuffer.java
index 68a71db..814e041 100644
--- a/libjava/java/nio/IntBuffer.java
+++ b/libjava/java/nio/IntBuffer.java
@@ -243,11 +243,27 @@ public abstract class IntBuffer extends Buffer
 
   /**
    * Calculates a hash code for this buffer.
+   *
+   * This is done with <code>int</code> arithmetic,
+   * where ** represents exponentiation, by this formula:<br>
+   * <code>s[position()] + 31 + (s[position()+1] + 30)*31**1 + ... +
+   * (s[limit()-1]+30)*31**(limit()-1)</code>.
+   * Where s is the buffer data. Note that the hashcode is dependent
+   * on buffer content, and therefore is not useful if the buffer
+   * content may change.
+   *
+   * @return the hash code
    */
   public int hashCode ()
   {
-    // FIXME: Check what SUN calculates here.
-    return super.hashCode ();
+    int hashCode = get(position()) + 31;
+    int multiplier = 1;
+    for (int i = position() + 1; i < limit(); ++i)
+      {
+	  multiplier *= 31;
+	  hashCode += (get(i) + 30)*multiplier;
+      }
+    return hashCode;
   }
 
   /**
diff --git a/libjava/java/nio/LongBuffer.java b/libjava/java/nio/LongBuffer.java
index c4066b1..6e9ef34 100644
--- a/libjava/java/nio/LongBuffer.java
+++ b/libjava/java/nio/LongBuffer.java
@@ -243,11 +243,27 @@ public abstract class LongBuffer extends Buffer
 
   /**
    * Calculates a hash code for this buffer.
+   *
+   * This is done with <code>long</code> arithmetic,
+   * where ** represents exponentiation, by this formula:<br>
+   * <code>s[position()] + 31 + (s[position()+1] + 30)*31**1 + ... +
+   * (s[limit()-1]+30)*31**(limit()-1)</code>.
+   * Where s is the buffer data. Note that the hashcode is dependent
+   * on buffer content, and therefore is not useful if the buffer
+   * content may change.
+   *
+   * @return the hash code (casted to int)
    */
   public int hashCode ()
   {
-    // FIXME: Check what SUN calculates here.
-    return super.hashCode ();
+    long hashCode = get(position()) + 31;
+    long multiplier = 1;
+    for (int i = position() + 1; i < limit(); ++i)
+      {
+	  multiplier *= 31;
+	  hashCode += (get(i) + 30)*multiplier;
+      }
+    return ((int)hashCode);
   }
 
   /**
diff --git a/libjava/java/nio/ShortBuffer.java b/libjava/java/nio/ShortBuffer.java
index 0830391..db03076 100644
--- a/libjava/java/nio/ShortBuffer.java
+++ b/libjava/java/nio/ShortBuffer.java
@@ -243,11 +243,27 @@ public abstract class ShortBuffer extends Buffer
 
   /**
    * Calculates a hash code for this buffer.
+   *
+   * This is done with <code>int</code> arithmetic,
+   * where ** represents exponentiation, by this formula:<br>
+   * <code>s[position()] + 31 + (s[position()+1] + 30)*31**1 + ... +
+   * (s[limit()-1]+30)*31**(limit()-1)</code>.
+   * Where s is the buffer data. Note that the hashcode is dependent
+   * on buffer content, and therefore is not useful if the buffer
+   * content may change.
+   *
+   * @return the hash code
    */
   public int hashCode ()
   {
-    // FIXME: Check what SUN calculates here.
-    return super.hashCode ();
+    int hashCode = get(position()) + 31;
+    int multiplier = 1;
+    for (int i = position() + 1; i < limit(); ++i)
+      {
+	  multiplier *= 31;
+	  hashCode += (get(i) + 30)*multiplier;
+      }
+    return hashCode;
   }
 
   /**