Implement onion3 string parsing

Author: ianopolous

src/main/java/io/ipfs/multiaddr/Protocol.java

@@ -140,6 +140,32 @@ public byte[] addressToBytes(String addr) {
                     dout.flush();
                     return b.toByteArray();
                 }
+                case ONION3: {
+                    String[] split = addr.split(":");
+                    if (split.length != 2)
+                        throw new IllegalStateException("Onion3 address needs a port: " + addr);
+
+                    // onion3 address without the ".onion" substring
+                    if (split[0].length() != 56)
+                        throw new IllegalStateException("failed to parse " + name() + " addr: " + addr + " not a Tor onion3 address.");
+
+                    byte[] onionHostBytes = Multibase.decode(Multibase.Base.Base32.prefix + split[0]);
+                    if (onionHostBytes.length != 35)
+                        throw new IllegalStateException("Invalid onion3 address host: " + split[0]);
+                    int port = Integer.parseInt(split[1]);
+                    if (port > 65535)
+                        throw new IllegalStateException("Port is > 65535: " + port);
+
+                    if (port < 1)
+                        throw new IllegalStateException("Port is < 1: " + port);
+
+                    ByteArrayOutputStream b = new ByteArrayOutputStream();
+                    DataOutputStream dout = new DataOutputStream(b);
+                    dout.write(onionHostBytes);
+                    dout.writeShort(port);
+                    dout.flush();
+                    return b.toByteArray();
+                }
                 case UNIX: {
                     if (addr.startsWith("/"))
                         addr = addr.substring(1);

src/test/java/io/ipfs/api/MultiAddressTest.java

@@ -141,21 +141,13 @@ public void equalsTests() {
             throw new IllegalStateException("Should be equal!");
     }
 
-    @Test
-    public void stringToBytes() {
-        BiConsumer<String, String> test = (s, h) -> {
-            if (!Arrays.equals(new MultiAddress(s).getBytes(), fromHex(h))) throw new IllegalStateException(s + " bytes != " + new MultiAddress(fromHex(h)));
-        };
-
-        test.accept("/ip4/127.0.0.1/udp/1234", "047f000001910204d2");
-        test.accept("/ip4/127.0.0.1/tcp/4321", "047f0000010610e1");
-        test.accept("/ip4/127.0.0.1/udp/1234/ip4/127.0.0.1/tcp/4321", "047f000001910204d2047f0000010610e1");
-    }
-
    @Test
-    public void bytesToString() {
+    public void conversion() {
         BiConsumer<String, String> test = (s, h) -> {
-            if (!s.equals(new MultiAddress(fromHex(h)).toString())) throw new IllegalStateException(s + " != " + new MultiAddress(fromHex(h)));
+            if (!s.equals(new MultiAddress(fromHex(h)).toString()))
+                throw new IllegalStateException(s + " != " + new MultiAddress(fromHex(h)));
+            if (! Arrays.equals(new MultiAddress(s).getBytes(), fromHex(h)))
+                throw new IllegalStateException("bytes for " + s + " != " + new MultiAddress(fromHex(h)));
         };
 
         test.accept("/ip4/159.89.141.29/udp/5491/quic", "049f598d1d91021573cc03");