From: Sven de Marothy <sven@physto.se>
Date: Tue, 21 Sep 2004 13:50:13 +0000 (+0200)
Subject: ByteBuffer.java (hashCode): Implemented.
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=9413382eec489236a06827e7dbff33975b249bb1;p=gcc.git

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
---

diff --git a/libjava/ChangeLog b/libjava/ChangeLog
index e32ff8c4fbe..c27d6ee96bb 100644
--- a/libjava/ChangeLog
+++ b/libjava/ChangeLog
@@ -1,3 +1,13 @@
+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.
+
 2004-09-21  Andreas Tobler  <a.tobler@schweiz.ch>
 
 	* javax/security/auth/x500/X500Principal.java: Fix some merge glitches.
diff --git a/libjava/java/nio/ByteBuffer.java b/libjava/java/nio/ByteBuffer.java
index 378e58827fa..e502e003199 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 4ef257bed68..700c56750f3 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 10055cd08d9..dd16ee04962 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 6d19503525f..2ead8cbc494 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 68a71db3b53..814e0414bc6 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 c4066b1d30b..6e9ef34e8eb 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 083039101e4..db03076b629 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;
   }
 
   /**