From e42e6686cc3b6f13a106ab5378385d96b340d46d Mon Sep 17 00:00:00 2001
From: Nicola Atzei <atzeinicola@gmail.com>
Date: Wed, 21 Feb 2018 11:27:58 +0100
Subject: [PATCH] ScriptChunk: Add method toByteArray().

---
 .../java/org/bitcoinj/script/ScriptChunk.java | 13 ++++
 .../org/bitcoinj/script/ScriptChunkTest.java  | 64 +++++++++++++++++++
 2 files changed, 77 insertions(+)

diff --git a/core/src/main/java/org/bitcoinj/script/ScriptChunk.java b/core/src/main/java/org/bitcoinj/script/ScriptChunk.java
index 41079a48..9c21ca73 100644
--- a/core/src/main/java/org/bitcoinj/script/ScriptChunk.java
+++ b/core/src/main/java/org/bitcoinj/script/ScriptChunk.java
@@ -21,6 +21,8 @@ import org.bitcoinj.core.Utils;
 import com.google.common.base.Objects;
 
 import javax.annotation.Nullable;
+
+import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.OutputStream;
 import java.util.Arrays;
@@ -138,6 +140,17 @@ public class ScriptChunk {
         }
     }
 
+    public byte[] toByteArray() {
+        ByteArrayOutputStream stream = new ByteArrayOutputStream();
+        try {
+            write(stream);
+        } catch (IOException e) {
+            // Should not happen as ByteArrayOutputStream does not throw IOException on write
+            throw new RuntimeException(e);
+        }
+        return stream.toByteArray();
+    }
+
     @Override
     public String toString() {
         StringBuilder buf = new StringBuilder();
diff --git a/core/src/test/java/org/bitcoinj/script/ScriptChunkTest.java b/core/src/test/java/org/bitcoinj/script/ScriptChunkTest.java
index 7ba2ea34..ba3c40db 100644
--- a/core/src/test/java/org/bitcoinj/script/ScriptChunkTest.java
+++ b/core/src/test/java/org/bitcoinj/script/ScriptChunkTest.java
@@ -16,16 +16,24 @@
 
 package org.bitcoinj.script;
 
+import static org.bitcoinj.script.ScriptOpCodes.OP_0;
+import static org.bitcoinj.script.ScriptOpCodes.OP_IF;
 import static org.bitcoinj.script.ScriptOpCodes.OP_PUSHDATA1;
 import static org.bitcoinj.script.ScriptOpCodes.OP_PUSHDATA2;
 import static org.bitcoinj.script.ScriptOpCodes.OP_PUSHDATA4;
+import static org.junit.Assert.assertArrayEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
 
+import java.util.Random;
+
 import org.junit.Test;
+import org.spongycastle.util.Arrays;
 
 public class ScriptChunkTest {
 
+    private static final Random RANDOM = new Random(42);
+
     @Test
     public void testShortestPossibleDataPush() {
         assertTrue("empty push", new ScriptBuilder().data(new byte[0]).build().getChunks().get(0)
@@ -46,4 +54,60 @@ public class ScriptChunkTest {
         assertFalse("push of 255 bytes", new ScriptChunk(OP_PUSHDATA2, new byte[255]).isShortestPossiblePushData());
         assertFalse("push of 65535 bytes", new ScriptChunk(OP_PUSHDATA4, new byte[65535]).isShortestPossiblePushData());
     }
+
+    @Test
+    public void testToByteArray_opcode() {
+        byte[] expected = new byte[] { OP_IF };
+        byte[] actual = new ScriptChunk(OP_IF, null).toByteArray();
+        assertArrayEquals(expected, actual);
+    }
+
+    @Test
+    public void testToByteArray_smallNum() {
+        byte[] expected = new byte[] { OP_0 };
+        byte[] actual = new ScriptChunk(OP_0, null).toByteArray();
+        assertArrayEquals(expected, actual);
+    }
+
+    @Test
+    public void testToByteArray_lt_OP_PUSHDATA1() {
+        // < OP_PUSHDATA1
+        for (byte len = 1; len < OP_PUSHDATA1; len++) {
+            byte[] bytes = new byte[len];
+            RANDOM.nextBytes(bytes);
+            byte[] expected = Arrays.concatenate(new byte[] { len }, bytes);
+            byte[] actual = new ScriptChunk(len, bytes).toByteArray();
+            assertArrayEquals(expected, actual);
+        }
+    }
+
+    @Test
+    public void testToByteArray_OP_PUSHDATA1() {
+        // OP_PUSHDATA1
+        byte[] bytes = new byte[0xFF];
+        RANDOM.nextBytes(bytes);
+        byte[] expected = Arrays.concatenate(new byte[] { OP_PUSHDATA1, (byte) 0xFF }, bytes);
+        byte[] actual = new ScriptChunk(OP_PUSHDATA1, bytes).toByteArray();
+        assertArrayEquals(expected, actual);
+    }
+
+    @Test
+    public void testToByteArray_OP_PUSHDATA2() {
+        // OP_PUSHDATA2
+        byte[] bytes = new byte[0x0102];
+        RANDOM.nextBytes(bytes);
+        byte[] expected = Arrays.concatenate(new byte[] { OP_PUSHDATA2, 0x02, 0x01 }, bytes);
+        byte[] actual = new ScriptChunk(OP_PUSHDATA2, bytes).toByteArray();
+        assertArrayEquals(expected, actual);
+    }
+
+    @Test
+    public void testToByteArray_OP_PUSHDATA4() {
+        // OP_PUSHDATA4
+        byte[] bytes = new byte[0x0102];
+        RANDOM.nextBytes(bytes);
+        byte[] expected = Arrays.concatenate(new byte[] { OP_PUSHDATA4, 0x02, 0x01, 0x00, 0x00 }, bytes);
+        byte[] actual = new ScriptChunk(OP_PUSHDATA4, bytes).toByteArray();
+        assertArrayEquals(expected, actual);
+    }
 }