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Fixed VarInt serialization bug for the 0xffffffff number. Fixed VarInt sizeOf bug for the 0xffffffff number and added tests for VarInt edge cases.

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The 4294967295 number (0xffffffff) was incorrectly serialized because the UnsignedInteger.MAX_VALUE.longValue() helper returned 4294967295 instead of expected 4294967296.

The VarInt.sizeOf() incorrectly returned 9 instead of 5 for the 4294967295 (0xffffffff) number.

See https://en.bitcoin.it/wiki/Protocol_specification#Variable_length_integer
This commit is contained in:
Piotr Włodarek 2014-06-19 22:28:52 +02:00 committed by Andreas Schildbach
parent ae3acdfefd
commit 3dfaf54e28
3 changed files with 27 additions and 6 deletions
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7
core/src/main/java/com/google/bitcoin/core/Utils.java
View File

@ -185,6 +185,13 @@ public class Utils {
return UnsignedLongs.compare(n1, n2) < 0;
}
/**
* Work around lack of unsigned types in Java.
*/
public static boolean isLessThanOrEqualToUnsigned(long n1, long n2) {
return UnsignedLongs.compare(n1, n2) <= 0;
}
/**
* Hex encoding used throughout the framework. Use with HEX.encode(byte[]) or HEX.decode(CharSequence).
*/

11
core/src/main/java/com/google/bitcoin/core/VarInt.java
View File

@ -16,9 +16,8 @@
package com.google.bitcoin.core;
import com.google.common.primitives.UnsignedInteger;
import static com.google.bitcoin.core.Utils.isLessThanUnsigned;
import static com.google.bitcoin.core.Utils.isLessThanOrEqualToUnsigned;
/**
* A variable-length encoded integer using Satoshis encoding.
@ -88,9 +87,9 @@ public class VarInt {
public static int sizeOf(long value) {
if (isLessThanUnsigned(value, 253))
return 1;
else if (isLessThanUnsigned(value, 65536))
else if (isLessThanOrEqualToUnsigned(value, 0xFFFFL))
return 3; // 1 marker + 2 data bytes
else if (isLessThanUnsigned(value, UnsignedInteger.MAX_VALUE.longValue()))
else if (isLessThanOrEqualToUnsigned(value, 0xFFFFFFFFL))
return 5; // 1 marker + 4 data bytes
else
return 9; // 1 marker + 8 data bytes
@ -99,9 +98,9 @@ public class VarInt {
public byte[] encode() {
if (isLessThanUnsigned(value, 253)) {
return new byte[]{(byte) value};
} else if (isLessThanUnsigned(value, 65536)) {
} else if (isLessThanOrEqualToUnsigned(value, 0xFFFFL)) {
return new byte[]{(byte) 253, (byte) (value), (byte) (value >> 8)};
} else if (isLessThanUnsigned(value, UnsignedInteger.MAX_VALUE.longValue())) {
} else if (isLessThanOrEqualToUnsigned(value, 0xFFFFFFFFL)) {
byte[] bytes = new byte[5];
bytes[0] = (byte) 254;
Utils.uint32ToByteArrayLE(value, bytes, 1);

15
core/src/test/java/com/google/bitcoin/core/VarIntTest.java
View File

@ -33,6 +33,13 @@ public class VarIntTest extends TestCase {
assertEquals(64000, new VarInt(a.encode(), 0).value);
}
public void testShortFFFF() throws Exception {
VarInt a = new VarInt(0xFFFFL);
assertEquals(3, a.getSizeInBytes());
assertEquals(3, a.encode().length);
assertEquals(0xFFFFL, new VarInt(a.encode(), 0).value);
}
public void testInts() throws Exception {
VarInt a = new VarInt(0xAABBCCDDL);
assertEquals(5, a.getSizeInBytes());
@ -41,6 +48,14 @@ public class VarIntTest extends TestCase {
assertEquals(0xAABBCCDDL, 0xFFFFFFFFL & new VarInt(bytes, 0).value);
}
public void testIntFFFFFFFF() throws Exception {
VarInt a = new VarInt(0xFFFFFFFFL);
assertEquals(5, a.getSizeInBytes());
assertEquals(5, a.encode().length);
byte[] bytes = a.encode();
assertEquals(0xFFFFFFFFL, 0xFFFFFFFFL & new VarInt(bytes, 0).value);
}
public void testLong() throws Exception {
VarInt a = new VarInt(0xCAFEBABEDEADBEEFL);
assertEquals(9, a.getSizeInBytes());