Modify version handling to match Dogecoin 1.10 style API

Calling getVersion() on an AuxPoW block now returns the lowest 8 bits
only, and a new getRawVersion() method is introduced to support fetching
full version.
Added unit tests to check unpacking of AuxPoW version numbers.

src/main/java/org/bitcoinj/core/AltcoinBlock.java

@@ -26,12 +26,14 @@ import java.io.IOException;
 import java.io.OutputStream;
 import java.math.BigInteger;
 import java.security.GeneralSecurityException;
+import java.util.BitSet;
 import java.util.List;
 
 import org.libdohj.core.ScryptHash;
 import static org.libdohj.core.Utils.scryptDigest;
 
 import static org.bitcoinj.core.Utils.reverseBytes;
+import org.libdohj.core.AuxPoWNetworkParameters;
 
 /**
  * <p>A block is a group of transactions, and is one of the fundamental data structures of the Bitcoin system.
@@ -44,17 +46,18 @@ import static org.bitcoinj.core.Utils.reverseBytes;
  * specifically using {@link Peer#getBlock(Sha256Hash)}, or grab one from a downloaded {@link BlockChain}.
  */
 public class AltcoinBlock extends org.bitcoinj.core.Block {
-	/** Bit used to indicate that a block contains an AuxPoW section, where the network supports AuxPoW */
-    public static final int BLOCK_VERSION_CHAIN_START = (1 << 16);
-    public static final int BLOCK_VERSION_CHAIN_END = (1 << 30);
-    public static final int BLOCK_VERSION_AUXPOW = (1 << 8);
-
     private boolean auxpowParsed = false;
     private boolean auxpowBytesValid = false;
 
     /** AuxPoW header element, if applicable. */
     @Nullable private AuxPoW auxpow;
 
+    /**
+     * Whether the chain this block belongs to support AuxPoW, used to avoid
+     * repeated instanceof checks. Initialised in parseTransactions()
+     */
+    private boolean auxpowChain = false;
+
     private ScryptHash scryptHash;
 
     /** Special case constructor, used for the genesis node, cloneAsHeader and unit tests. */
@@ -115,7 +118,6 @@ public class AltcoinBlock extends org.bitcoinj.core.Block {
     }
 
     public AuxPoW getAuxPoW() {
-        // TODO: maybeParseAuxPoW();
         return this.auxpow;
     }
 
@@ -136,14 +138,65 @@ public class AltcoinBlock extends org.bitcoinj.core.Block {
         return getScryptHash().toString();
     }
 
+    /**
+     * Get the chain ID (upper 16 bits) from an AuxPoW version number.
+     */
+    public static long getChainID(final long rawVersion) {
+        return rawVersion >> 16;
+    }
+
+    /**
+     * Return chain ID from block version of an AuxPoW-enabled chain.
+     */
+    public long getChainID() {
+        return getChainID(this.getRawVersion());
+    }
+
+    /**
+     * Return flags from block version of an AuxPoW-enabled chain.
+     * 
+     * @return flags as a bitset. 
+     */
+    public BitSet getVersionFlags() {
+        return BitSet.valueOf(new long[] {(this.getRawVersion() & 0xff00) >> 8});
+    }
+
+    /**
+     * Return block version without applying any filtering (i.e. for AuxPoW blocks
+     * which structure version differently to pack in additional data).
+     */
+    public final long getRawVersion() {
+        return super.getVersion();
+    }
+
+    /**
+     * Get the base version (i.e. Bitcoin-like version number) out of a packed
+     * AuxPoW version number (i.e. one that contains chain ID and feature flags).
+     */
+    public static long getBaseVersion(final long rawVersion) {
+        return rawVersion & 0xff;
+    }
+
+    @Override
+    public long getVersion() {
+        // TODO: Can we cache the individual parts on parse?
+        if (this.params instanceof AltcoinNetworkParameters) {
+            // AuxPoW networks use the higher block version bits for flags and
+            // chain ID.
+            return getBaseVersion(super.getVersion());
+        } else {
+            return super.getVersion();
+        }
+    }
+
     protected void parseAuxPoW() throws ProtocolException {
         if (this.auxpowParsed)
             return;
 
         this.auxpow = null;
-        if (this.params instanceof AltcoinNetworkParameters) {
-            final AltcoinNetworkParameters altcoinParams = (AltcoinNetworkParameters)this.params;
-            if (altcoinParams.isAuxPoWBlockVersion(this.getVersion())) {
+        if (this.auxpowChain) {
+            final AuxPoWNetworkParameters auxpowParams = (AuxPoWNetworkParameters)this.params;
+            if (auxpowParams.isAuxPoWBlockVersion(this.getRawVersion())) {
                 // The following is used in dogecoinj, but I don't think we necessarily need it
                 // payload.length >= 160) { // We have at least 2 headers in an Aux block. Workaround for StoredBlocks
                 this.auxpow = new AuxPoW(params, payload, cursor, this, serializer);
@@ -157,6 +210,7 @@ public class AltcoinBlock extends org.bitcoinj.core.Block {
 
     @Override
     protected void parseTransactions(final int offset) {
+        this.auxpowChain = params instanceof AuxPoWNetworkParameters;
         parseAuxPoW();
         if (null != this.auxpow) {
             super.parseTransactions(offset + auxpow.getMessageSize());
@@ -176,7 +230,7 @@ public class AltcoinBlock extends org.bitcoinj.core.Block {
     /** Returns a copy of the block, but without any transactions. */
     @Override
     public Block cloneAsHeader() {
-        AltcoinBlock block = new AltcoinBlock(params, getVersion());
+        AltcoinBlock block = new AltcoinBlock(params, getRawVersion());
         super.copyBitcoinHeaderTo(block);
         block.auxpow = auxpow;
         return block;
@@ -187,8 +241,8 @@ public class AltcoinBlock extends org.bitcoinj.core.Block {
         if (params instanceof AltcoinNetworkParameters) {
             BigInteger target = getDifficultyTargetAsInteger();
         
-            final AltcoinNetworkParameters altParams = (AltcoinNetworkParameters)auxpow;
-            if (altParams.isAuxPoWBlockVersion(getVersion()) && null != auxpow) {
+            final AuxPoWNetworkParameters altParams = (AuxPoWNetworkParameters)auxpow;
+            if (altParams.isAuxPoWBlockVersion(getRawVersion()) && null != auxpow) {
                 return auxpow.checkProofOfWork(this.getHash(), target, throwException);
             }
 

src/main/java/org/bitcoinj/core/AuxPoW.java

@@ -18,7 +18,7 @@
 
 package org.bitcoinj.core;
 
-import org.libdohj.core.AltcoinNetworkParameters;
+import org.libdohj.core.AuxPoWNetworkParameters;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -239,14 +239,14 @@ public class AuxPoW extends ChildMessage {
      */
     protected boolean checkProofOfWork(Sha256Hash hashAuxBlock,
         BigInteger target, boolean throwException) throws VerificationException {
-        if (!(params instanceof AltcoinNetworkParameters)) {
+        if (!(params instanceof AuxPoWNetworkParameters)) {
             if (throwException) {
                 // Should be impossible
-                throw new VerificationException("Network parameters are not an instance of AltcoinNetworkParameters, AuxPoW support is not available.");
+                throw new VerificationException("Network parameters are not an instance of AuxPoWNetworkParameters, AuxPoW support is not available.");
             }
             return false;
         }
-        final AltcoinNetworkParameters altcoinParams = (AltcoinNetworkParameters) params;
+        final AuxPoWNetworkParameters altcoinParams = (AuxPoWNetworkParameters) params;
         
         if (0 != this.getCoinbaseBranch().getIndex()) {
             if (throwException) {
@@ -257,7 +257,7 @@ public class AuxPoW extends ChildMessage {
         }
 
         if (!altcoinParams.isTestNet()
-            && getChainID(parentBlockHeader) == altcoinParams.getChainID()) {
+            && parentBlockHeader.getChainID() == altcoinParams.getChainID()) {
             if (throwException) {
                 throw new VerificationException("Aux POW parent has our chain ID");
             }
@@ -362,7 +362,7 @@ public class AuxPoW extends ChildMessage {
         // for the same slot.
         long rand = nonce;
         rand = rand * 1103515245 + 12345;
-        rand += ((AltcoinNetworkParameters) params).getChainID();
+        rand += ((AuxPoWNetworkParameters) params).getChainID();
         rand = rand * 1103515245 + 12345;
 
         if (getChainMerkleBranch().getIndex() != (rand % branchSize)) {
@@ -407,13 +407,6 @@ public class AuxPoW extends ChildMessage {
         return true;
     }
 
-    /**
-     * Get the chain ID from a block header.
-     */
-    public static long getChainID(final Block blockHeader) {
-        return blockHeader.getVersion() / AltcoinBlock.BLOCK_VERSION_CHAIN_START;
-    }
-
     /**
      * Set the merkle branch used to connect the coinbase transaction to the
      * parent block header.

src/main/java/org/bitcoinj/core/ConvertAddress.java

@@ -16,7 +16,7 @@ public class ConvertAddress {
     public static void main(final String[] argv) throws AddressFormatException {
         final NetworkParameters mainParams = MainNetParams.get();
         final NetworkParameters dogeParams = DogecoinMainNetParams.get();
-        final Address address = Address.fromBase58(mainParams, "1NS17iag9jJgTHD1VXjvLCEnZuQ3rJDE9L");
+        final Address address = Address.fromBase58(mainParams, "175tWpb8K1S7NmH4Zx6rewF9WQrcZv245W");
         final Address newAddress = new Address(dogeParams, 30, address.getHash160());
 
         System.out.println(newAddress.toBase58());

src/main/java/org/libdohj/core/AltcoinNetworkParameters.java

@@ -20,14 +20,9 @@ import org.bitcoinj.core.Sha256Hash;
 
 /**
  *
- * @author jrn
+ * @author Ross Nicoll
  */
 public interface AltcoinNetworkParameters {
-
-    boolean isAuxPoWBlockVersion(long version);
-
-    int getChainID();
-
     /**
      * Get the hash for the given block, for comparing against target difficulty.
      * This provides an extension hook for networks which use a hash other than

src/main/java/org/libdohj/core/AuxPoWNetworkParameters.java

@@ -0,0 +1,27 @@
+/*
+ * Copyright 2015 Ross Nicoll
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.libdohj.core;
+
+/**
+ *
+ * @author Ross Nicoll
+ */
+public interface AuxPoWNetworkParameters extends AltcoinNetworkParameters {
+
+    boolean isAuxPoWBlockVersion(long version);
+
+    int getChainID();
+}

src/main/java/org/libdohj/params/AbstractDogecoinParams.java

@@ -35,18 +35,19 @@ import org.bitcoinj.utils.MonetaryFormat;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import org.libdohj.core.AltcoinSerializer;
 import org.bitcoinj.core.Sha256Hash;
 import org.bitcoinj.core.StoredBlock;
 import org.bitcoinj.core.Transaction;
 import org.bitcoinj.core.TransactionInput;
 import org.bitcoinj.core.TransactionOutput;
 import org.bitcoinj.core.Utils;
+import org.libdohj.core.AltcoinSerializer;
+import org.libdohj.core.AuxPoWNetworkParameters;
 
 /**
  * Parameters for the main Dogecoin production network on which people trade goods and services.
  */
-public abstract class AbstractDogecoinParams extends NetworkParameters implements AltcoinNetworkParameters {
+public abstract class AbstractDogecoinParams extends NetworkParameters implements AuxPoWNetworkParameters {
     /** Standard format for the DOGE denomination. */
     public static final MonetaryFormat DOGE;
     /** Standard format for the mDOGE denomination. */
@@ -69,9 +70,8 @@ public abstract class AbstractDogecoinParams extends NetworkParameters implement
     /** Currency code for base 1/100,000,000 Dogecoin. */
     public static final String CODE_KOINU = "Koinu";
 
-    public static final int BLOCK_VERSION_DEFAULT = 0x00000002;
-    public static final int BLOCK_VERSION_AUXPOW = 0x00620002;
-    public static final int BLOCK_VERSION_FLAG_AUXPOW = 0x00000100;
+    private static final int BLOCK_MIN_VERSION_AUXPOW = 0x00620002;
+    private static final int BLOCK_VERSION_FLAG_AUXPOW = 0x00000100;
 
     static {
         DOGE = MonetaryFormat.BTC.noCode()
@@ -311,7 +311,7 @@ public abstract class AbstractDogecoinParams extends NetworkParameters implement
 
     @Override
     public boolean isAuxPoWBlockVersion(long version) {
-        return version >= BLOCK_VERSION_AUXPOW
+        return version >= BLOCK_MIN_VERSION_AUXPOW
             && (version & BLOCK_VERSION_FLAG_AUXPOW) > 0;
     }
 }

src/test/java/org/bitcoinj/core/AuxPoWTest.java

@@ -2,17 +2,20 @@ package org.bitcoinj.core;
 
 import java.util.Arrays;
 import java.util.Collections;
+
 import org.libdohj.core.AltcoinSerializer;
+import org.libdohj.core.AuxPoWNetworkParameters;
 import org.libdohj.params.DogecoinMainNetParams;
-import org.junit.Test;
 
 import static org.bitcoinj.core.Util.getBytes;
 import static org.bitcoinj.core.Utils.reverseBytes;
 
 import static org.junit.Assert.assertArrayEquals;
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
 import org.junit.Before;
 import org.junit.Rule;
+import org.junit.Test;
 import org.junit.rules.ExpectedException;
 
 /**
@@ -97,7 +100,9 @@ public class AuxPoWTest {
         byte[] payload = Util.getBytes(getClass().getResourceAsStream("dogecoin_block371337.bin"));
         AltcoinSerializer serializer = (AltcoinSerializer)params.getDefaultSerializer();
         final AltcoinBlock block = (AltcoinBlock)serializer.makeBlock(payload);
+        assertEquals(98, block.getChainID());
         final AuxPoW auxpow = block.getAuxPoW();
+        assertNotNull(auxpow);
         auxpow.setParentBlockHeader((AltcoinBlock)block.cloneAsHeader());
         expectedEx.expect(org.bitcoinj.core.VerificationException.class);
         expectedEx.expectMessage("Aux POW parent has our chain ID");

src/test/java/org/bitcoinj/core/DogecoinBlockTest.java

@@ -12,6 +12,7 @@ import static org.junit.Assert.assertArrayEquals;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
 import org.junit.Before;
 import org.junit.Test;
 
@@ -27,6 +28,24 @@ public class DogecoinBlockTest {
         Context context = new Context(params);
     }
 
+    @Test
+    public void shouldExtractChainID() {
+        final long baseVersion = 2;
+        final long flags = 1;
+        final long chainID = 98;
+        final long auxpowVersion = (chainID << 16) | (flags << 8) | baseVersion;
+        assertEquals(chainID, AltcoinBlock.getChainID(auxpowVersion));
+    }
+
+    @Test
+    public void shouldExtractBaseVersion() {
+        final long baseVersion = 2;
+        final long flags = 1;
+        final long chainID = 98;
+        final long auxpowVersion = (chainID << 16) | (flags << 8) | baseVersion;
+        assertEquals(baseVersion, AltcoinBlock.getBaseVersion(auxpowVersion));
+    }
+
     @Test
     public void shouldParseBlock1() throws IOException {
         byte[] payload = Util.getBytes(getClass().getResourceAsStream("dogecoin_block1.bin"));
@@ -65,6 +84,12 @@ public class DogecoinBlockTest {
         final AltcoinBlock block = (AltcoinBlock)serializer.makeBlock(payload);
         assertEquals("60323982f9c5ff1b5a954eac9dc1269352835f47c2c5222691d80f0d50dcf053", block.getHashAsString());
         assertEquals(0, block.getNonce());
+
+        // Check block version values
+        assertEquals(2, block.getVersion());
+        assertEquals(98, block.getChainID());
+        assertTrue(block.getVersionFlags().get(0));
+
         final AuxPoW auxpow = block.getAuxPoW();
         assertNotNull(auxpow);
         final Transaction auxpowCoinbase = auxpow.getCoinbase();
@@ -75,18 +100,18 @@ public class DogecoinBlockTest {
 
         final MerkleBranch blockchainMerkleBranch = auxpow.getChainMerkleBranch();
         Sha256Hash[] expected = new Sha256Hash[] {
-            new Sha256Hash("b541c848bc001d07d2bdf8643abab61d2c6ae50d5b2495815339a4b30703a46f"),
-            new Sha256Hash("78d6abe48cee514cf3496f4042039acb7e27616dcfc5de926ff0d6c7e5987be7"),
-            new Sha256Hash("a0469413ce64d67c43902d54ee3a380eff12ded22ca11cbd3842e15d48298103")
+            Sha256Hash.wrap("b541c848bc001d07d2bdf8643abab61d2c6ae50d5b2495815339a4b30703a46f"),
+            Sha256Hash.wrap("78d6abe48cee514cf3496f4042039acb7e27616dcfc5de926ff0d6c7e5987be7"),
+            Sha256Hash.wrap("a0469413ce64d67c43902d54ee3a380eff12ded22ca11cbd3842e15d48298103")
         };
 
         assertArrayEquals(expected, blockchainMerkleBranch.getHashes().toArray(new Sha256Hash[blockchainMerkleBranch.size()]));
 
         final MerkleBranch coinbaseMerkleBranch = auxpow.getCoinbaseBranch();
         expected = new Sha256Hash[] {
-            new Sha256Hash("cd3947cd5a0c26fde01b05a3aa3d7a38717be6ae11d27239365024db36a679a9"),
-            new Sha256Hash("48f9e8fef3411944e27f49ec804462c9e124dca0954c71c8560e8a9dd218a452"),
-            new Sha256Hash("d11293660392e7c51f69477a6130237c72ecee2d0c1d3dc815841734c370331a")
+            Sha256Hash.wrap("cd3947cd5a0c26fde01b05a3aa3d7a38717be6ae11d27239365024db36a679a9"),
+            Sha256Hash.wrap("48f9e8fef3411944e27f49ec804462c9e124dca0954c71c8560e8a9dd218a452"),
+            Sha256Hash.wrap("d11293660392e7c51f69477a6130237c72ecee2d0c1d3dc815841734c370331a")
         };
         assertArrayEquals(expected, coinbaseMerkleBranch.getHashes().toArray(new Sha256Hash[coinbaseMerkleBranch.size()]));