address parsing support

src/main/java/com/sparrowwallet/drongo/address/Address.java

@@ -1,8 +1,13 @@
 package com.sparrowwallet.drongo.address;
 
 import com.sparrowwallet.drongo.protocol.Base58;
+import com.sparrowwallet.drongo.protocol.Bech32;
 import com.sparrowwallet.drongo.protocol.ScriptType;
 
+import java.util.Arrays;
+
+import static com.sparrowwallet.drongo.address.P2WPKHAddress.HRP;
+
 public abstract class Address {
     protected final byte[] hash;
 
@@ -42,4 +47,53 @@ public abstract class Address {
     public int hashCode() {
         return getAddress().hashCode();
     }
+
+    public static Address fromString(String address) throws InvalidAddressException {
+        Exception nested = null;
+
+        if(address != null && (address.startsWith("1") || address.startsWith("3"))) {
+            try {
+                byte[] decodedBytes = Base58.decodeChecked(address);
+                if(decodedBytes.length == 21) {
+                    int version = decodedBytes[0];
+                    byte[] hash = Arrays.copyOfRange(decodedBytes, 1, 21);
+                    if(version == 0) {
+                        return new P2PKHAddress(hash);
+                    }
+                    if(version == 5) {
+                        return new P2SHAddress(hash);
+                    }
+                }
+            } catch (Exception e) {
+                nested = e;
+            }
+        }
+
+        if(address != null && address.startsWith(HRP)) {
+            try {
+                Bech32.Bech32Data data = Bech32.decode(address);
+                if (data.hrp.equals(HRP)) {
+                    int witnessVersion = data.data[0];
+                    if (witnessVersion == 0) {
+                        byte[] convertedProgram = Arrays.copyOfRange(data.data, 1, data.data.length);
+                        byte[] witnessProgram = Bech32.convertBits(convertedProgram, 0, convertedProgram.length, 5, 8, false);
+                        if (witnessProgram.length == 20) {
+                            return new P2WPKHAddress(witnessProgram);
+                        }
+                        if (witnessProgram.length == 32) {
+                            return new P2WSHAddress(witnessProgram);
+                        }
+                    }
+                }
+            } catch (Exception e) {
+                nested = e;
+            }
+        }
+
+        if(nested != null) {
+            throw new InvalidAddressException("Could not parse invalid address " + address, nested);
+        }
+
+        throw new InvalidAddressException("Could not parse invalid address " + address);
+    }
 }

src/main/java/com/sparrowwallet/drongo/address/InvalidAddressException.java

@@ -0,0 +1,19 @@
+package com.sparrowwallet.drongo.address;
+
+public class InvalidAddressException extends Exception {
+    public InvalidAddressException() {
+        super();
+    }
+
+    public InvalidAddressException(String msg) {
+        super(msg);
+    }
+
+    public InvalidAddressException(Throwable cause) {
+        super(cause);
+    }
+
+    public InvalidAddressException(String message, Throwable cause) {
+        super(message, cause);
+    }
+}

src/main/java/com/sparrowwallet/drongo/protocol/Bech32.java

@@ -178,7 +178,7 @@ public class Bech32 {
     /**
      * Helper for re-arranging bits into groups.
      */
-    private static byte[] convertBits(final byte[] in, final int inStart, final int inLen, final int fromBits,
+    public static byte[] convertBits(final byte[] in, final int inStart, final int inLen, final int fromBits,
                                       final int toBits, final boolean pad) {
         int acc = 0;
         int bits = 0;

src/main/java/com/sparrowwallet/drongo/wallet/UtxoSelector.java

@@ -0,0 +1,7 @@
+package com.sparrowwallet.drongo.wallet;
+
+import java.util.Collection;
+
+public interface UtxoSelector {
+    Collection<BlockTransactionHashIndex> select(long targetValue, Collection<BlockTransactionHashIndex> candidates);
+}

src/test/java/com/sparrowwallet/drongo/address/AddressTest.java

@@ -0,0 +1,70 @@
+package com.sparrowwallet.drongo.address;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.security.SecureRandom;
+
+public class AddressTest {
+    @Test
+    public void validAddressTest() throws InvalidAddressException {
+        Address address1 = Address.fromString("bc1qw508d6qejxtdg4y5r3zarvary0c5xw7kv8f3t4");
+        Assert.assertTrue(address1 instanceof P2WPKHAddress);
+        Assert.assertEquals("bc1qw508d6qejxtdg4y5r3zarvary0c5xw7kv8f3t4", address1.toString());
+
+        Address address2 = Address.fromString("bc1qrp33g0q5c5txsp9arysrx4k6zdkfs4nce4xj0gdcccefvpysxf3qccfmv3");
+        Assert.assertTrue(address2 instanceof P2WSHAddress);
+        Assert.assertEquals("bc1qrp33g0q5c5txsp9arysrx4k6zdkfs4nce4xj0gdcccefvpysxf3qccfmv3", address2.toString());
+
+        Address address3 = Address.fromString("19Sp9dLinHy3dKo2Xxj53ouuZWAoVGGhg8");
+        Assert.assertTrue(address3 instanceof P2PKHAddress);
+        Assert.assertEquals("19Sp9dLinHy3dKo2Xxj53ouuZWAoVGGhg8", address3.toString());
+
+        Address address4 = Address.fromString("34jnjFM4SbaB7Q8aMtNDG849RQ1gUYgpgo");
+        Assert.assertTrue(address4 instanceof P2SHAddress);
+        Assert.assertEquals("34jnjFM4SbaB7Q8aMtNDG849RQ1gUYgpgo", address4.toString());
+    }
+
+    @Test
+    public void validRandomAddressTest() throws InvalidAddressException {
+        SecureRandom random = new SecureRandom();
+        byte[] values = new byte[20];
+
+        for(int i = 0; i < 100; i++) {
+            random.nextBytes(values);
+            Address address = (i % 2 == 0 ? new P2PKHAddress(values) : new P2WPKHAddress(values));
+            String strAddress = address.toString();
+            Address checkAddress = Address.fromString(strAddress);
+            Assert.assertArrayEquals(values, checkAddress.getHash());
+        }
+
+        byte[] values32 = new byte[32];
+        for(int i = 0; i < 100; i++) {
+            random.nextBytes(values32);
+            Address address = new P2WSHAddress(values32);
+            String strAddress = address.toString();
+            Address checkAddress = Address.fromString(strAddress);
+            Assert.assertArrayEquals(values32, checkAddress.getHash());
+        }
+    }
+
+    @Test(expected = InvalidAddressException.class)
+    public void invalidCharacterAddressTest() throws InvalidAddressException {
+        Address address1 = Address.fromString("bc1qw508d6qejxtdg4y5R3zarvary0c5xw7kv8f3t4");
+    }
+
+    @Test(expected = InvalidAddressException.class)
+    public void invalidVersionAddressTest() throws InvalidAddressException {
+        Address address1 = Address.fromString("44jnjFM4SbaB7Q8aMtNDG849RQ1gUYgpgo");
+    }
+
+    @Test(expected = InvalidAddressException.class)
+    public void invalidChecksumAddressTest() throws InvalidAddressException {
+        Address address1 = Address.fromString("34jnjFM4SbaB7Q7aMtNDG849RQ1gUYgpgo");
+    }
+
+    @Test(expected = InvalidAddressException.class)
+    public void invalidChecksumAddressTest2() throws InvalidAddressException {
+        Address address1 = Address.fromString("bc1qrp33g0q5c5txsp9arysrx4k6zdkfs4nce4xj0gdcccefvpysxf3qccfmb3");
+    }
+}