<HTML><BODY style="word-wrap: break-word; -khtml-nbsp-mode: space; -khtml-line-break: after-white-space; "><DIV><BR class="khtml-block-placeholder"></DIV><DIV><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>Do you have a license for this? Seems like something I could use as a decent hash provider.</DIV><BR><DIV><DIV>On Apr 10, 2007, at 16:20 , Pierre Demartines wrote:</DIV><BR class="Apple-interchange-newline"><BLOCKQUOTE type="cite"><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">FYI, we found the Fowler-Noll-Vo hashes to be very quick to compute, and</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">yet having beautiful properties in terms of dispersion.</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">FWIW, here is a simple Java implementation that computes a 64-bit</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">hashcode for a class that extends CharSequence:</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">package com.yourco.util;</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">/**</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> </SPAN>* Enables a CharSequence with the capability to produce a</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Fowler-Noll-Vo (FNV) 64-bit hashcode.<p></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> </SPAN>*<SPAN class="Apple-converted-space"> </SPAN></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> </SPAN>* FNV hashes are designed to be fast while maintaining a low collision</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">rate.</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> </SPAN>* The FNV speed allows one to quickly hash lots of data while</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">maintaining a</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> </SPAN>* reasonable collision rate. The high dispersion of the FNV hashes</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">makes them</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> </SPAN>* well suited for hashing nearly identical strings such as URLs,</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">hostnames,</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> </SPAN>* filenames, text, IP addresses, etc.</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> </SPAN>*<SPAN class="Apple-converted-space"> </SPAN></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> </SPAN>* Usage: add "extends CharSequenceHash64" to a class that implements</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">CharSequence,</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> </SPAN>* and that class will have hashCode64().<p></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> </SPAN>*<SPAN class="Apple-converted-space"> </SPAN></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> </SPAN>* You can daisy-chain several hashCode calculations like this:<p></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> </SPAN>* <pre>long hashOfSeveral =</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">a.hashCode64(b.hashCode64(c.hashCode64()));</pre><p></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> </SPAN>* or, alternatively, like that:</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> </SPAN>* <pre></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> </SPAN>* long hashOfSeveral = CharSequenceHash64.FNV1_64_INIT;</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> </SPAN>* for (MyCharSequence x : collectionOfMyCharSequences) {</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> </SPAN>*<SPAN class="Apple-converted-space"> </SPAN>hashOfSeveral = x.hashCode64(hashOfSeveral);</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> </SPAN>* }</pre><p></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> </SPAN>* @see <A href="http://www.isthe.com/chongo/tech/comp/fnv/">http://www.isthe.com/chongo/tech/comp/fnv/</A><SPAN class="Apple-converted-space"> </SPAN>and</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> </SPAN>* @see <A href="http://en.wikipedia.org/wiki/Fowler_Noll_Vo_hash">http://en.wikipedia.org/wiki/Fowler_Noll_Vo_hash</A><p></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> </SPAN>*<SPAN class="Apple-converted-space"> </SPAN></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> </SPAN>* @author <A href="mailto:pdemartines@quantcast.com">pdemartines@quantcast.com</A></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> </SPAN>*/</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">public abstract class CharSequenceHash64 implements CharSequence {</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>public<SPAN class="Apple-converted-space"> </SPAN>static final long FNV1_64_INIT = 0xcbf29ce484222325L;</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>private static final long FNV_64_PRIME = 0x100000001b3L;</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>/**</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN> * @param initialValue -- optional: initial value</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN> * @return a 64-bit FNV hash called fnv164</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN> */</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>public long hashCode64(long initialValue) {</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>long hval = initialValue;</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>int len = length();</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>for (int i=0; i<len; i++) {</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>hval *= FNV_64_PRIME;</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>hval ^= (long)charAt(i);</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>}</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>return hval;</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>}</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>public long hashCode64() {</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>return hashCode64(FNV1_64_INIT);</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>}</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">}</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Here is a junit test for it, that shows how it can be used:</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">package com.yourco.util;</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">import java.util.HashMap;</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">import junit.framework.TestCase;</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">public class CharSequenceHash64_T extends TestCase {</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>public class MyCharSeq extends CharSequenceHash64 implements</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">CharSequence {</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>private char[] buffer = null;</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>private MyCharSeq() {}</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>private MyCharSeq(int length) {</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>buffer = new char[length];</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>}</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>public MyCharSeq(String s) {</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>buffer = s.toCharArray();</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>}</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>public int length() {</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>return (buffer == null ? 0 : buffer.length);</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>}</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>public char charAt(int index) {</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>if (index < length()) {</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>return buffer[index];</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>} else {</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>throw new IndexOutOfBoundsException();</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>}</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>}</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>public String toString() {</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>if (buffer == null) return "";</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>return new String(buffer);</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>}</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>public CharSequence subSequence(int start, int end) {</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>if (buffer == null) throw new IndexOutOfBoundsException();</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>int length = end-start;</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>MyCharSeq sub = new MyCharSeq(length);</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>System.arraycopy(buffer, start, sub.buffer, 0, end-start);</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>return sub;</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>}</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>}</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> </SPAN>// FNV's hashCode64</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> </SPAN>// Compare this function's value against known values (calculated</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">using bona-fide implementations of FNV164)</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> </SPAN>public void testHashCode64() {</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> <SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN></SPAN>HashMap<String,Long> value = new HashMap<String,Long>();</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> <SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN></SPAN>value.put("", new Long(0xcbf29ce484222325L));</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> <SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN></SPAN>value.put(" ", new Long(0xaf63bd4c8601b7ffL));</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> <SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN></SPAN>value.put("hello world!", new Long(0x58735284b97b86bcL));</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> <SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN></SPAN>value.put("Lorem ipsum dolor sit amet, consectetuer adipiscing</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">elit.", new Long(0x536c9cdee87c054aL));</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> <SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN></SPAN>value.put("wd:com.google", new Long(0xcf4e7986071b08f8L));</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> <SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN></SPAN>value.put("wd:com.google ", new Long(0x5d6176be12f03d48L));</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> <SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN></SPAN>for (String s:value.keySet()) {</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> <SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN></SPAN>long h64 = value.get(s);</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> <SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN></SPAN>assertEquals("\""+s+"\".hashCode64()", h64, new</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">MyCharSeq(s).hashCode64());</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> <SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN></SPAN>}</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> </SPAN>}</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">}</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Enjoy,</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">~Pierre</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">On Tue, 2007-04-10 at 23:01 +0100, Richard Jones wrote:</DIV> <BLOCKQUOTE type="cite"><BLOCKQUOTE type="cite"><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>This is a very interesting idea, and I'd like to add a consistent</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">hash driver to my java interface, but there's a bit of gap between</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">your writeup and what the implementation.</DIV> </BLOCKQUOTE><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Check the init() method - that builds up the appropriate data structure (a<SPAN class="Apple-converted-space"> </SPAN></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">TreeMap called buckets iirc). You can use any hashing mechanism you want<SPAN class="Apple-converted-space"> </SPAN></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">instead of the md5 thing, that just seemed a convenient way to generate a<SPAN class="Apple-converted-space"> </SPAN></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">bunch of hashes. If you change it you won't be compatible with other<SPAN class="Apple-converted-space"> </SPAN></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">implementations - not a problem if you are exclusively using java tho.</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Once you've build the data structure using the servers list, that is pretty<SPAN class="Apple-converted-space"> </SPAN></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">much it in java, just check how keys are mapped to servers in findPointFor().</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">RJ</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV> <BLOCKQUOTE type="cite"><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>In the java interface, all I see is that you've added a new hash</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">type that's based off an MD5.<SPAN class="Apple-converted-space"> </SPAN>Is that actually an important detail?</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">It seems like you should be able to use any hash that produces an</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">even 32-bits.</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>Is it OK if I use your C implementation as a specification?</DIV> </BLOCKQUOTE><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV> </BLOCKQUOTE><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV> </BLOCKQUOTE></DIV><BR><DIV> <SPAN class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><DIV>-- </DIV><DIV>Dustin Sallings</DIV><BR class="Apple-interchange-newline"></SPAN> </DIV><BR></BODY></HTML>