Index: java/util/zip/Adler32.java
===================================================================
RCS file: /cvsroot/classpath/classpath/java/util/zip/Adler32.java,v
retrieving revision 1.5
diff -u -r1.5 Adler32.java
--- java/util/zip/Adler32.java	22 Jan 2002 22:27:02 -0000	1.5
+++ java/util/zip/Adler32.java	15 May 2005 19:46:45 -0000
@@ -1,5 +1,5 @@
 /* Adler32.java - Computes Adler32 data checksum of a data stream
-   Copyright (C) 1999, 2000, 2001 Free Software Foundation, Inc.
+   Copyright (C) 1999, 2000, 2001, 2005 Free Software Foundation, Inc.
 
 This file is part of GNU Classpath.
 
@@ -153,6 +153,19 @@
   }
 
   /**
+   * In update() we can defer the modulo operation:
+   * s1 maximally grows from 65521 (BASE) to 65521 + 255 * 3800
+   * s2 maximally grows by 3800 * median(s1) = 2090079800 < 2^31
+   * Calculated this value like this:
+   *
+   * int i = 0, a = BASE, b = a;
+   * for(; b > 0; i++)
+   *     b += (a += 255);
+   * System.out.println("max defer = " + (i - 1));
+   */
+  private static final int DEFER = 3850;
+
+  /**
    * Updates the checksum with the bytes taken from the array. 
    * 
    * @param buf an array of bytes
@@ -161,20 +174,13 @@
    */
   public void update (byte[] buf, int off, int len)
   {
-    //(By Per Bothner)
     int s1 = checksum & 0xffff;
     int s2 = checksum >>> 16;
-
-    while (len > 0)
+    
+    while (off < len)
       {
-	// We can defer the modulo operation:
-	// s1 maximally grows from 65521 to 65521 + 255 * 3800
-	// s2 maximally grows by 3800 * median(s1) = 2090079800 < 2^31
-	int n = 3800;
-	if (n > len)
-	  n = len;
-	len -= n;
-	while (--n >= 0)
+	int max = Math.min(off + DEFER, len);
+	while (off < max)
 	  {
 	    s1 = s1 + (buf[off++] & 0xFF);
 	    s2 = s2 + s1;
@@ -182,16 +188,6 @@
 	s1 %= BASE;
 	s2 %= BASE;
       }
-
-    /*Old implementation, borrowed from somewhere:
-    int n;
-    
-    while (len-- > 0) {
-
-      s1 = (s1 + (bs[offset++] & 0xff)) % BASE; 
-      s2 = (s2 + s1) % BASE;
-    }*/
-    
     checksum = (s2 << 16) | s1;
   }