Author: stack
Date: Sun Sep 4 22:58:11 2011
New Revision: 1165127
URL: http://svn.apache.org/viewvc?rev=1165127&view=rev
Log:
HBASE-4206 jenkins hash implementation uses longs unnecessarily
Modified:
hbase/trunk/CHANGES.txt
hbase/trunk/src/main/java/org/apache/hadoop/hbase/util/JenkinsHash.java
Modified: hbase/trunk/CHANGES.txt
URL:
http://svn.apache.org/viewvc/hbase/trunk/CHANGES.txt?rev=1165127&r1=1165126&r2=1165127&view=diff
==============================================================================
--- hbase/trunk/CHANGES.txt (original)
+++ hbase/trunk/CHANGES.txt Sun Sep 4 22:58:11 2011
@@ -441,6 +441,8 @@ Release 0.91.0 - Unreleased
HBASE-4257 Limit the number of regions in transitions displayed on
master webpage. (todd)
HBASE-1730 Online Schema Changes
+ HBASE-4206 jenkins hash implementation uses longs unnecessarily
+ (Ron Yang)
TASKS
HBASE-3559 Move report of split to master OFF the heartbeat channel
Modified:
hbase/trunk/src/main/java/org/apache/hadoop/hbase/util/JenkinsHash.java
URL:
http://svn.apache.org/viewvc/hbase/trunk/src/main/java/org/apache/hadoop/hbase/util/JenkinsHash.java?rev=1165127&r1=1165126&r2=1165127&view=diff
==============================================================================
--- hbase/trunk/src/main/java/org/apache/hadoop/hbase/util/JenkinsHash.java
(original)
+++ hbase/trunk/src/main/java/org/apache/hadoop/hbase/util/JenkinsHash.java Sun
Sep 4 22:58:11 2011
@@ -20,6 +20,8 @@
package org.apache.hadoop.hbase.util;
+import static java.lang.Integer.rotateLeft;
+
import java.io.FileInputStream;
import java.io.IOException;
@@ -39,8 +41,7 @@ import java.io.IOException;
* Dr. Dobbs Article</a>
*/
public class JenkinsHash extends Hash {
- private static long INT_MASK = 0x00000000ffffffffL;
- private static long BYTE_MASK = 0x00000000000000ffL;
+ private static final int BYTE_MASK = 0xff;
private static JenkinsHash _instance = new JenkinsHash();
@@ -48,11 +49,6 @@ public class JenkinsHash extends Hash {
return _instance;
}
- private static long rot(long val, int pos) {
- return ((Integer.rotateLeft(
- (int)(val & INT_MASK), pos)) & INT_MASK);
- }
-
/**
* taken from hashlittle() -- hash a variable-length key into a 32-bit value
*
@@ -82,23 +78,22 @@ public class JenkinsHash extends Hash {
@SuppressWarnings("fallthrough")
public int hash(byte[] key, int off, int nbytes, int initval) {
int length = nbytes;
- long a, b, c; // We use longs because we don't have unsigned ints
- a = b = c = (0x00000000deadbeefL + length + initval) & INT_MASK;
+ int a, b, c;
+ a = b = c = 0xdeadbeef + length + initval;
int offset = off;
for (; length > 12; offset += 12, length -= 12) {
- //noinspection PointlessArithmeticExpression
- a = (a + (key[offset + 0] & BYTE_MASK)) & INT_MASK;
- a = (a + (((key[offset + 1] & BYTE_MASK) << 8) & INT_MASK)) & INT_MASK;
- a = (a + (((key[offset + 2] & BYTE_MASK) << 16) & INT_MASK)) & INT_MASK;
- a = (a + (((key[offset + 3] & BYTE_MASK) << 24) & INT_MASK)) & INT_MASK;
- b = (b + (key[offset + 4] & BYTE_MASK)) & INT_MASK;
- b = (b + (((key[offset + 5] & BYTE_MASK) << 8) & INT_MASK)) & INT_MASK;
- b = (b + (((key[offset + 6] & BYTE_MASK) << 16) & INT_MASK)) & INT_MASK;
- b = (b + (((key[offset + 7] & BYTE_MASK) << 24) & INT_MASK)) & INT_MASK;
- c = (c + (key[offset + 8] & BYTE_MASK)) & INT_MASK;
- c = (c + (((key[offset + 9] & BYTE_MASK) << 8) & INT_MASK)) & INT_MASK;
- c = (c + (((key[offset + 10] & BYTE_MASK) << 16) & INT_MASK)) & INT_MASK;
- c = (c + (((key[offset + 11] & BYTE_MASK) << 24) & INT_MASK)) & INT_MASK;
+ a += (key[offset] & BYTE_MASK);
+ a += ((key[offset + 1] & BYTE_MASK) << 8);
+ a += ((key[offset + 2] & BYTE_MASK) << 16);
+ a += ((key[offset + 3] & BYTE_MASK) << 24);
+ b += (key[offset + 4] & BYTE_MASK);
+ b += ((key[offset + 5] & BYTE_MASK) << 8);
+ b += ((key[offset + 6] & BYTE_MASK) << 16);
+ b += ((key[offset + 7] & BYTE_MASK) << 24);
+ c += (key[offset + 8] & BYTE_MASK);
+ c += ((key[offset + 9] & BYTE_MASK) << 8);
+ c += ((key[offset + 10] & BYTE_MASK) << 16);
+ c += ((key[offset + 11] & BYTE_MASK) << 24);
/*
* mix -- mix 3 32-bit values reversibly.
@@ -154,44 +149,44 @@ public class JenkinsHash extends Hash {
*
* mix(a,b,c);
*/
- a = (a - c) & INT_MASK; a ^= rot(c, 4); c = (c + b) & INT_MASK;
- b = (b - a) & INT_MASK; b ^= rot(a, 6); a = (a + c) & INT_MASK;
- c = (c - b) & INT_MASK; c ^= rot(b, 8); b = (b + a) & INT_MASK;
- a = (a - c) & INT_MASK; a ^= rot(c,16); c = (c + b) & INT_MASK;
- b = (b - a) & INT_MASK; b ^= rot(a,19); a = (a + c) & INT_MASK;
- c = (c - b) & INT_MASK; c ^= rot(b, 4); b = (b + a) & INT_MASK;
+ a -= c; a ^= rotateLeft(c, 4); c += b;
+ b -= a; b ^= rotateLeft(a, 6); a += c;
+ c -= b; c ^= rotateLeft(b, 8); b += a;
+ a -= c; a ^= rotateLeft(c, 16); c += b;
+ b -= a; b ^= rotateLeft(a, 19); a += c;
+ c -= b; c ^= rotateLeft(b, 4); b += a;
}
//-------------------------------- last block: affect all 32 bits of (c)
switch (length) { // all the case statements fall through
case 12:
- c = (c + (((key[offset + 11] & BYTE_MASK) << 24) & INT_MASK)) & INT_MASK;
+ c += ((key[offset + 11] & BYTE_MASK) << 24);
case 11:
- c = (c + (((key[offset + 10] & BYTE_MASK) << 16) & INT_MASK)) & INT_MASK;
+ c += ((key[offset + 10] & BYTE_MASK) << 16);
case 10:
- c = (c + (((key[offset + 9] & BYTE_MASK) << 8) & INT_MASK)) & INT_MASK;
+ c += ((key[offset + 9] & BYTE_MASK) << 8);
case 9:
- c = (c + (key[offset + 8] & BYTE_MASK)) & INT_MASK;
+ c += (key[offset + 8] & BYTE_MASK);
case 8:
- b = (b + (((key[offset + 7] & BYTE_MASK) << 24) & INT_MASK)) & INT_MASK;
+ b += ((key[offset + 7] & BYTE_MASK) << 24);
case 7:
- b = (b + (((key[offset + 6] & BYTE_MASK) << 16) & INT_MASK)) & INT_MASK;
+ b += ((key[offset + 6] & BYTE_MASK) << 16);
case 6:
- b = (b + (((key[offset + 5] & BYTE_MASK) << 8) & INT_MASK)) & INT_MASK;
+ b += ((key[offset + 5] & BYTE_MASK) << 8);
case 5:
- b = (b + (key[offset + 4] & BYTE_MASK)) & INT_MASK;
+ b += (key[offset + 4] & BYTE_MASK);
case 4:
- a = (a + (((key[offset + 3] & BYTE_MASK) << 24) & INT_MASK)) & INT_MASK;
+ a += ((key[offset + 3] & BYTE_MASK) << 24);
case 3:
- a = (a + (((key[offset + 2] & BYTE_MASK) << 16) & INT_MASK)) & INT_MASK;
+ a += ((key[offset + 2] & BYTE_MASK) << 16);
case 2:
- a = (a + (((key[offset + 1] & BYTE_MASK) << 8) & INT_MASK)) & INT_MASK;
+ a += ((key[offset + 1] & BYTE_MASK) << 8);
case 1:
//noinspection PointlessArithmeticExpression
- a = (a + (key[offset + 0] & BYTE_MASK)) & INT_MASK;
+ a += (key[offset + 0] & BYTE_MASK);
break;
case 0:
- return (int)(c & INT_MASK);
+ return c;
}
/*
* final -- final mixing of 3 32-bit values (a,b,c) into c
@@ -230,15 +225,14 @@ public class JenkinsHash extends Hash {
* }
*
*/
- c ^= b; c = (c - rot(b,14)) & INT_MASK;
- a ^= c; a = (a - rot(c,11)) & INT_MASK;
- b ^= a; b = (b - rot(a,25)) & INT_MASK;
- c ^= b; c = (c - rot(b,16)) & INT_MASK;
- a ^= c; a = (a - rot(c,4)) & INT_MASK;
- b ^= a; b = (b - rot(a,14)) & INT_MASK;
- c ^= b; c = (c - rot(b,24)) & INT_MASK;
-
- return (int)(c & INT_MASK);
+ c ^= b; c -= rotateLeft(b, 14);
+ a ^= c; a -= rotateLeft(c, 11);
+ b ^= a; b -= rotateLeft(a, 25);
+ c ^= b; c -= rotateLeft(b, 16);
+ a ^= c; a -= rotateLeft(c, 4);
+ b ^= a; b -= rotateLeft(a, 14);
+ c ^= b; c -= rotateLeft(b, 24);
+ return c;
}
/**
@@ -255,7 +249,7 @@ public class JenkinsHash extends Hash {
byte[] bytes = new byte[512];
int value = 0;
JenkinsHash hash = new JenkinsHash();
- for (int length = in.read(bytes); length > 0 ; length = in.read(bytes)) {
+ for (int length = in.read(bytes); length > 0; length = in.read(bytes)) {
value = hash.hash(bytes, length, value);
}
System.out.println(Math.abs(value));
