WIP VersionedChecksummedBytes: Store network params rather than version, in preparation for Segwit addresses.

This also does away with the concept of "acceptable version codes" (for a network), because this list of two versions is not likely to expand.

Author: Andreas Schildbach

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

@@ -18,17 +18,16 @@
 
 package org.bitcoinj.core;
 
-import java.io.IOException;
-import java.io.ObjectInputStream;
-import java.io.ObjectOutputStream;
+import static com.google.common.base.Preconditions.checkArgument;
 
-import org.bitcoinj.params.Networks;
-import org.bitcoinj.script.Script;
+import java.util.Arrays;
 
 import javax.annotation.Nullable;
 
-import static com.google.common.base.Preconditions.checkArgument;
-import static com.google.common.base.Preconditions.checkNotNull;
+import org.bitcoinj.params.Networks;
+import org.bitcoinj.script.Script;
+
+import com.google.common.base.Objects;
 
 /**
  * <p>A Bitcoin address looks like 1MsScoe2fTJoq4ZPdQgqyhgWeoNamYPevy and is derived from an elliptic curve public key
@@ -47,26 +46,31 @@ public class Address extends VersionedChecksummedBytes {
      */
     public static final int LENGTH = 20;
 
-    private transient NetworkParameters params;
+    /** True if P2SH, false if P2PKH. */
+    public final boolean p2sh;
 
     /**
      * Construct an address from parameters, the address version, and the hash160 form. Example:<p>
      *
      * <pre>new Address(MainNetParams.get(), NetworkParameters.getAddressHeader(), Hex.decode("4a22c3c4cbb31e4d03b15550636762bda0baf85a"));</pre>
      */
-    public Address(NetworkParameters params, int version, byte[] hash160) throws WrongNetworkException {
-        super(version, hash160);
-        checkNotNull(params);
+    public Address(NetworkParameters params, boolean p2sh, byte[] hash160) throws WrongNetworkException {
+        super(params, hash160);
         checkArgument(hash160.length == 20, "Addresses are 160-bit hashes, so you must provide 20 bytes");
-        if (!isAcceptableVersion(params, version))
-            throw new WrongNetworkException(version);
-        this.params = params;
+        this.p2sh = p2sh;
+    }
+
+    /**
+     * Constructs a P2PKH address.
+     */
+    public Address(NetworkParameters params, byte[] hash160) throws WrongNetworkException {
+        this(params, false, hash160);
     }
 
     /** Returns an Address that represents the given P2SH script hash. */
     public static Address fromP2SHHash(NetworkParameters params, byte[] hash160) {
         try {
-            return new Address(params, params.getP2SHHeader(), hash160);
+            return new Address(params, true, hash160);
         } catch (WrongNetworkException e) {
             throw new RuntimeException(e);  // Cannot happen.
         }
@@ -90,44 +94,31 @@ public static Address fromP2SHScript(NetworkParameters params, Script scriptPubK
      *             if the given address is valid but for a different chain (eg testnet vs mainnet)
      */
     public static Address fromBase58(@Nullable NetworkParameters params, String base58) throws AddressFormatException {
-        return new Address(params, base58);
-    }
-
-    /**
-     * Construct an address from parameters and the hash160 form. Example:<p>
-     *
-     * <pre>new Address(MainNetParams.get(), Hex.decode("4a22c3c4cbb31e4d03b15550636762bda0baf85a"));</pre>
-     */
-    public Address(NetworkParameters params, byte[] hash160) {
-        super(params.getAddressHeader(), hash160);
-        checkArgument(hash160.length == 20, "Addresses are 160-bit hashes, so you must provide 20 bytes");
-        this.params = params;
-    }
-
-    /** @deprecated Use {@link #fromBase58(NetworkParameters, String)} */
-    @Deprecated
-    public Address(@Nullable NetworkParameters params, String address) throws AddressFormatException {
-        super(address);
-        if (params != null) {
-            if (!isAcceptableVersion(params, version)) {
-                throw new WrongNetworkException(version);
-            }
-            this.params = params;
-        } else {
-            NetworkParameters paramsFound = null;
+        byte[] versionAndDataBytes = Base58.decodeChecked(base58);
+        int version = versionAndDataBytes[0] & 0xFF;
+        byte[] bytes = Arrays.copyOfRange(versionAndDataBytes, 1, versionAndDataBytes.length);
+        if (params == null) {
             for (NetworkParameters p : Networks.get()) {
-                if (isAcceptableVersion(p, version)) {
-                    paramsFound = p;
-                    break;
-                }
+                if (version == p.getAddressHeader())
+                    return new Address(p, false, bytes);
+                else if (version == p.getP2SHHeader())
+                    return new Address(p, true, bytes);
             }
-            if (paramsFound == null)
-                throw new AddressFormatException("No network found for " + address);
-
-            this.params = paramsFound;
+            throw new AddressFormatException("No network found for " + base58);
+        } else {
+            if (version == params.getAddressHeader())
+                return new Address(params, false, bytes);
+            else if (version == params.getP2SHHeader())
+                return new Address(params, true, bytes);
+            throw new WrongNetworkException(version);
         }
     }
 
+    @Override
+    protected int getVersion() {
+        return p2sh ? params.getP2SHHeader() : params.getAddressHeader();
+    }
+
     /** The (big endian) 20 byte hash that is the core of a Bitcoin address. */
     public byte[] getHash160() {
         return bytes;
@@ -138,8 +129,7 @@ public byte[] getHash160() {
      * See also https://github.com/bitcoin/bips/blob/master/bip-0013.mediawiki: Address Format for pay-to-script-hash
      */
     public boolean isP2SHAddress() {
-        final NetworkParameters parameters = getParameters();
-        return parameters != null && this.version == parameters.p2shHeader;
+        return p2sh;
     }
 
     /**
@@ -169,15 +159,19 @@ public static NetworkParameters getParametersFromAddress(String address) throws
         }
     }
 
-    /**
-     * Check if a given address version is valid given the NetworkParameters.
-     */
-    private static boolean isAcceptableVersion(NetworkParameters params, int version) {
-        if (version == params.getAddressHeader())
-            return true;
-        if (version == params.getP2SHHeader())
+    @Override
+    public boolean equals(Object o) {
+        if (this == o)
             return true;
-        return false;
+        if (o == null || getClass() != o.getClass())
+            return false;
+        Address other = (Address) o;
+        return super.equals(other) && this.p2sh == other.p2sh;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hashCode(super.hashCode(), p2sh);
     }
 
     /**
@@ -187,16 +181,4 @@ private static boolean isAcceptableVersion(NetworkParameters params, int version
     public Address clone() throws CloneNotSupportedException {
         return (Address) super.clone();
     }
-
-    // Java serialization
-
-    private void writeObject(ObjectOutputStream out) throws IOException {
-        out.defaultWriteObject();
-        out.writeUTF(params.id);
-    }
-
-    private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException {
-        in.defaultReadObject();
-        params = NetworkParameters.fromID(in.readUTF());
-    }
 }

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

@@ -17,13 +17,14 @@
 
 package org.bitcoinj.core;
 
-import com.google.common.base.Objects;
 import com.google.common.base.Preconditions;
 
 import java.util.Arrays;
 
 import javax.annotation.Nullable;
 
+import org.bitcoinj.params.Networks;
+
 /**
  * Parses and generates private keys in the form used by the Bitcoin "dumpprivkey" command. This is the private key
  * bytes with a header byte and 4 checksum bytes at the end. If there are 33 private key bytes instead of 32, then
@@ -42,13 +43,37 @@ public class DumpedPrivateKey extends VersionedChecksummedBytes {
      * @throws WrongNetworkException
      *             if the given private key is valid but for a different chain (eg testnet vs mainnet)
      */
-    public static DumpedPrivateKey fromBase58(@Nullable NetworkParameters params,String base58) throws AddressFormatException {
-        return new DumpedPrivateKey(params, base58);
+    public static DumpedPrivateKey fromBase58(@Nullable NetworkParameters params, String base58)
+            throws AddressFormatException {
+        byte[] versionAndDataBytes = Base58.decodeChecked(base58);
+        int version = versionAndDataBytes[0] & 0xFF;
+        byte[] bytes = Arrays.copyOfRange(versionAndDataBytes, 1, versionAndDataBytes.length);
+        if (params == null) {
+            for (NetworkParameters p : Networks.get())
+                if (version == p.getDumpedPrivateKeyHeader())
+                    return new DumpedPrivateKey(p, bytes);
+            throw new AddressFormatException("No network found for " + base58);
+        } else {
+            if (version == params.getDumpedPrivateKeyHeader())
+                return new DumpedPrivateKey(params, bytes);
+            throw new WrongNetworkException(version);
+        }
+    }
+
+    private DumpedPrivateKey(NetworkParameters params, byte[] bytes) {
+        super(params, bytes);
+        if (bytes.length != 32 && bytes.length != 33)
+            throw new AddressFormatException("Wrong number of bytes for a private key, not 32 or 33");
     }
 
     // Used by ECKey.getPrivateKeyEncoded()
     DumpedPrivateKey(NetworkParameters params, byte[] keyBytes, boolean compressed) {
-        super(params.getDumpedPrivateKeyHeader(), encode(keyBytes, compressed));
+        this(params, encode(keyBytes, compressed));
+    }
+
+    @Override
+    protected int getVersion() {
+        return params.getDumpedPrivateKeyHeader();
     }
 
     private static byte[] encode(byte[] keyBytes, boolean compressed) {
@@ -64,17 +89,6 @@ private static byte[] encode(byte[] keyBytes, boolean compressed) {
         }
     }
 
-    /** @deprecated Use {@link #fromBase58(NetworkParameters, String)} */
-    @Deprecated
-    public DumpedPrivateKey(@Nullable NetworkParameters params, String encoded) throws AddressFormatException {
-        super(encoded);
-        if (params != null && version != params.getDumpedPrivateKeyHeader())
-            throw new WrongNetworkException(version);
-        if (bytes.length != 32 && bytes.length != 33) {
-            throw new AddressFormatException("Wrong number of bytes for a private key, not 32 or 33");
-        }
-    }
-
     /**
      * Returns an ECKey created from this encoded private key.
      */
@@ -88,17 +102,4 @@ public ECKey getKey() {
     public boolean isPubKeyCompressed() {
         return bytes.length == 33 && bytes[32] == 1;
     }
-
-    @Override
-    public boolean equals(Object o) {
-        if (this == o) return true;
-        if (o == null || getClass() != o.getClass()) return false;
-        DumpedPrivateKey other = (DumpedPrivateKey) o;
-        return version == other.version && Arrays.equals(bytes, other.bytes);
-    }
-
-    @Override
-    public int hashCode() {
-        return Objects.hashCode(version, Arrays.hashCode(bytes));
-    }
 }

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

@@ -513,7 +513,7 @@ public boolean isCompressed() {
      * the RIPEMD-160 hash of the public key and is not the public key itself (which is too large to be convenient).
      */
     public Address toAddress(NetworkParameters params) {
-        return new Address(params, getPubKeyHash());
+        return new Address(params, false, getPubKeyHash());
     }
 
     /**