From 7b8eab19ff1d25f94d2f37f2bb32243970be69e0 Mon Sep 17 00:00:00 2001
From: Mike Hearn <mike@plan99.net>
Date: Fri, 29 Mar 2013 16:41:28 +0000
Subject: [PATCH] Use a bit of Guava for unsigned longs. Resolves issue 367.

---
 core/src/main/java/com/google/bitcoin/core/Utils.java  | 4 ++--
 core/src/main/java/com/google/bitcoin/core/VarInt.java | 8 ++++----
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/core/src/main/java/com/google/bitcoin/core/Utils.java b/core/src/main/java/com/google/bitcoin/core/Utils.java
index 7f8d68a9..f1a06ea2 100644
--- a/core/src/main/java/com/google/bitcoin/core/Utils.java
+++ b/core/src/main/java/com/google/bitcoin/core/Utils.java
@@ -16,7 +16,7 @@
 
 package com.google.bitcoin.core;
 
-import com.google.common.util.concurrent.CycleDetectingLockFactory;
+import com.google.common.primitives.UnsignedLongs;
 import org.spongycastle.crypto.digests.RIPEMD160Digest;
 import org.spongycastle.util.encoders.Hex;
 
@@ -202,7 +202,7 @@ public class Utils {
      * Work around lack of unsigned types in Java.
      */
     public static boolean isLessThanUnsigned(long n1, long n2) {
-        return (n1 < n2) ^ ((n1 < 0) != (n2 < 0));
+        return UnsignedLongs.compare(n1, n2) < 0;
     }
 
     /**
diff --git a/core/src/main/java/com/google/bitcoin/core/VarInt.java b/core/src/main/java/com/google/bitcoin/core/VarInt.java
index 2b1b4b66..e315dde1 100644
--- a/core/src/main/java/com/google/bitcoin/core/VarInt.java
+++ b/core/src/main/java/com/google/bitcoin/core/VarInt.java
@@ -16,6 +16,8 @@
 
 package com.google.bitcoin.core;
 
+import com.google.common.primitives.UnsignedInteger;
+
 import static com.google.bitcoin.core.Utils.isLessThanUnsigned;
 
 /**
@@ -73,7 +75,6 @@ public class VarInt {
      * Gets the minimum encoded size of the given value.
      */
     public static int sizeOf(int value) {
-        // Java doesn't have the actual value of MAX_INT, as all types in Java are signed.
         if (value < 253)
             return 1;
         else if (value < 65536)
@@ -85,12 +86,11 @@ public class VarInt {
      * Gets the minimum encoded size of the given value.
      */
     public static int sizeOf(long value) {
-        // Java doesn't have the actual value of MAX_INT, as all types in Java are signed.
         if (isLessThanUnsigned(value, 253))
             return 1;
         else if (isLessThanUnsigned(value, 65536))
             return 3;  // 1 marker + 2 data bytes
-        else if (isLessThanUnsigned(value, 4294967296L))
+        else if (isLessThanUnsigned(value, UnsignedInteger.MAX_VALUE.longValue()))
             return 5;  // 1 marker + 4 data bytes
         else
             return 9;  // 1 marker + 8 data bytes
@@ -106,7 +106,7 @@ public class VarInt {
             return new byte[]{(byte) value};
         } else if (isLessThanUnsigned(value, 65536)) {
             return new byte[]{(byte) 253, (byte) (value), (byte) (value >> 8)};
-        } else if (isLessThanUnsigned(value, 4294967295L)) {
+        } else if (isLessThanUnsigned(value, UnsignedInteger.MAX_VALUE.longValue())) {
             byte[] bytes = new byte[5];
             bytes[0] = (byte) 254;
             Utils.uint32ToByteArrayLE(value, bytes, 1);