From 63f3d88f785172f747e7f049dfc8badecd963e96 Mon Sep 17 00:00:00 2001
From: zzz <zzz@i2pmail.org>
Date: Tue, 22 Feb 2022 09:57:35 -0500
Subject: [PATCH] Util: Speed up PRNG nextInt() and nextLong()
Add signedNextInt()
---
.../src/net/i2p/util/FortunaRandomSource.java | 33 +++++++++++------
core/java/src/net/i2p/util/RandomSource.java | 37 +++++--------------
2 files changed, 32 insertions(+), 38 deletions(-)
diff --git a/core/java/src/net/i2p/util/FortunaRandomSource.java b/core/java/src/net/i2p/util/FortunaRandomSource.java
index 67eeacdb27..11dc355264 100644
--- a/core/java/src/net/i2p/util/FortunaRandomSource.java
+++ b/core/java/src/net/i2p/util/FortunaRandomSource.java
@@ -17,6 +17,7 @@ import java.util.Random;
import net.i2p.I2PAppContext;
import net.i2p.crypto.EntropyHarvester;
+import net.i2p.data.DataHelper;
/**
* Wrapper around GNU-Crypto's Fortuna PRNG. This seeds from /dev/urandom and
@@ -87,9 +88,21 @@ public class FortunaRandomSource extends RandomSource implements EntropyHarveste
rv %= n;
return rv;
}
-
+
@Override
- public int nextInt() { return signedNextInt(Integer.MAX_VALUE); }
+ public int nextInt() {
+ return signedNextInt() & 0x7fffffff;
+ }
+
+ /**
+ * @return all possible int values, positive and negative
+ * @since 0.9.54
+ */
+ public int signedNextInt() {
+ byte[] b = new byte[4];
+ nextBytes(b);
+ return (int) DataHelper.fromLong(b, 0, 4);
+ }
/**
* Implementation from Sun's java.util.Random javadocs
@@ -125,23 +138,21 @@ public class FortunaRandomSource extends RandomSource implements EntropyHarveste
@Override
public long nextLong(long n) {
if (n == 0) return 0;
- long rv = signedNextLong();
+ long rv = nextLong();
if (rv < 0)
rv = 0 - rv;
rv %= n;
return rv;
}
- @Override
- public long nextLong() { return signedNextLong(); }
-
/**
- * Implementation from Sun's java.util.Random javadocs
+ * @return all possible long values, positive and negative
*/
- private long signedNextLong() {
- synchronized(_fortuna) {
- return ((long)nextBits(32) << 32) + nextBits(32);
- }
+ @Override
+ public long nextLong() {
+ byte[] b = new byte[8];
+ nextBytes(b);
+ return DataHelper.fromLong8(b, 0);
}
@Override
diff --git a/core/java/src/net/i2p/util/RandomSource.java b/core/java/src/net/i2p/util/RandomSource.java
index 645f1870a0..85555f005c 100644
--- a/core/java/src/net/i2p/util/RandomSource.java
+++ b/core/java/src/net/i2p/util/RandomSource.java
@@ -72,6 +72,16 @@ public class RandomSource extends SecureRandom implements EntropyHarvester {
return val;
}
+ /**
+ * This code unused, see FortunaRandomSource override
+ *
+ * @return all possible int values, positive and negative
+ * @since 0.9.54
+ */
+ public int signedNextInt() {
+ return nextInt();
+ }
+
/**
* Like the modified nextInt, nextLong(n) returns a random number from 0 through n,
* including 0, excluding n.
@@ -103,33 +113,6 @@ public class RandomSource extends SecureRandom implements EntropyHarvester {
}
}
- /**
- * override as synchronized, for those JVMs that don't always pull via
- * nextBytes (cough ibm)
-
- @Override
- public boolean nextBoolean() { return super.nextBoolean(); }
-
- @Override
- public void nextBytes(byte buf[]) { super.nextBytes(buf); }
-
- @Override
- public double nextDouble() { return super.nextDouble(); }
-
- @Override
- public float nextFloat() { return super.nextFloat(); }
-
- @Override
- public double nextGaussian() { return super.nextGaussian(); }
-
- @Override
- public int nextInt() { return super.nextInt(); }
-
- @Override
- public long nextLong() { return super.nextLong(); }
-*****/
-
- /** */
public EntropyHarvester harvester() { return _entropyHarvester; }
public void feedEntropy(String source, long data, int bitoffset, int bits) {
--
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