From a504328044768af1ed498f9c24bda2c4bf107502 Mon Sep 17 00:00:00 2001
From: Mike Hearn <hearn@google.com>
Date: Sun, 13 Mar 2011 21:29:25 +0000
Subject: [PATCH] Improve VarInt: simplify, fix some minor bugs and increase
 test coverage.

---
 src/com/google/bitcoin/core/VarInt.java       | 21 ++++++++--------
 tests/com/google/bitcoin/core/VarIntTest.java | 24 ++++++++++++-------
 2 files changed, 27 insertions(+), 18 deletions(-)

diff --git a/src/com/google/bitcoin/core/VarInt.java b/src/com/google/bitcoin/core/VarInt.java
index df47c4c0..cc56e3ef 100644
--- a/src/com/google/bitcoin/core/VarInt.java
+++ b/src/com/google/bitcoin/core/VarInt.java
@@ -16,6 +16,8 @@
 
 package com.google.bitcoin.core;
 
+import static com.google.bitcoin.core.Utils.isLessThanUnsigned;
+
 public class VarInt {
     public final long value;
     
@@ -44,13 +46,12 @@ public class VarInt {
     }
     
     public int getSizeInBytes() {
-        // Java doesn't have the actual value of MAX_INT, as all types in Java
-        // are signed *headsmash*.
-        if (value < 253)
+        // 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 (value <= 65536)
+        else if (isLessThanUnsigned(value, 65536))
             return 3;  // 1 marker + 2 data bytes
-        else if (value <= 4294967295L)
+        else if (isLessThanUnsigned(value, 4294967296L))
             return 5;  // 1 marker + 4 data bytes
         else
             return 9;  // 1 marker + 8 data bytes
@@ -63,11 +64,11 @@ public class VarInt {
     
 
     public byte[] encodeBE() {
-        if (Utils.isLessThanUnsigned(value, 253)) {
+        if (isLessThanUnsigned(value, 253)) {
             return new byte[] { (byte)value };
-        } else if (Utils.isLessThanUnsigned(value, 65536)) {
+        } else if (isLessThanUnsigned(value, 65536)) {
             return new byte[] { (byte) 253, (byte) (value), (byte) (value >> 8) };
-        } else if (Utils.isLessThanUnsigned(value, 4294967295L)) {
+        } else if (isLessThanUnsigned(value, 4294967295L)) {
             byte[] bytes = new byte[5];
             bytes[0] = (byte) 254;
             Utils.uint32ToByteArrayLE(value, bytes, 1);
@@ -75,8 +76,8 @@ public class VarInt {
         } else {
             byte[] bytes = new byte[9];
             bytes[0] = (byte) 255;
-            Utils.uint32ToByteArrayLE(value & 0xFFFFFFFF, bytes, 1);
-            Utils.uint32ToByteArrayLE(value >> 32, bytes, 5);
+            Utils.uint32ToByteArrayLE(value, bytes, 1);
+            Utils.uint32ToByteArrayLE(value >>> 32, bytes, 5);
             return bytes;
         }
     }
diff --git a/tests/com/google/bitcoin/core/VarIntTest.java b/tests/com/google/bitcoin/core/VarIntTest.java
index 05b2e70a..c17b4d6e 100644
--- a/tests/com/google/bitcoin/core/VarIntTest.java
+++ b/tests/com/google/bitcoin/core/VarIntTest.java
@@ -19,25 +19,33 @@ package com.google.bitcoin.core;
 import junit.framework.TestCase;
 
 public class VarIntTest extends TestCase {
-    public void testVarInts() throws Exception {
-        VarInt a;
-
-        // Bytes
-        a = new VarInt(10);
+    public void testBytes() throws Exception {
+        VarInt a = new VarInt(10);
         assertEquals(1, a.getSizeInBytes());
         assertEquals(1, a.encode().length);
         assertEquals(10, new VarInt(a.encode(), 0).value);
+    }
 
-        // Shorts
-        a = new VarInt(64000);
+    public void testShorts() throws Exception {
+        VarInt a = new VarInt(64000);
         assertEquals(3, a.getSizeInBytes());
         assertEquals(3, a.encode().length);
         assertEquals(64000, new VarInt(a.encode(), 0).value);
+    }
 
-        a = new VarInt(0xAABBCCDDL);
+    public void testInts() throws Exception {
+        VarInt a = new VarInt(0xAABBCCDDL);
         assertEquals(5, a.getSizeInBytes());
         assertEquals(5, a.encode().length);
         byte[] bytes = a.encode();
         assertEquals(0xAABBCCDDL, 0xFFFFFFFFL & new VarInt(bytes, 0).value);
     }
+
+    public void testLong() throws Exception {
+        VarInt a = new VarInt(0xCAFEBABEDEADBEEFL);
+        assertEquals(9, a.getSizeInBytes());
+        assertEquals(9, a.encode().length);
+        byte[] bytes = a.encode();
+        assertEquals(0xCAFEBABEDEADBEEFL, new VarInt(bytes, 0).value);
+    }
 }