Moved BitUtils#readSignature to ByteInput

ByteInput#readSignature behaves similarly, except mismatch will reset position to before reading

core/src/com/riiablo/io/BitUtils.java

@@ -1,10 +1,5 @@
 package com.riiablo.io;
 
-import java.util.Arrays;
-import org.apache.logging.log4j.Logger;
-
-import com.riiablo.util.DebugUtils;
-
 public class BitUtils {
   private BitUtils() {}
 
@@ -29,27 +24,4 @@ public class BitUtils {
   public static boolean isUnsigned(long value) {
     return isUnsigned(value, Long.SIZE);
   }
-
-  public static boolean readSignature(ByteInput in, final byte[] SIGNATURE, Logger log, String tag) {
-    log.trace("Validating " + tag + " signature");
-    if (in.bytesRemaining() < SIGNATURE.length) {
-      byte[] signature = in.readBytes(in.bytesRemaining());
-      throw new InvalidFormat(
-          in,
-          String.format(tag + " signature doesn't match expected signature: %s, expected %s",
-          DebugUtils.toByteArray(signature),
-          DebugUtils.toByteArray(SIGNATURE)));
-    }
-
-    byte[] signature = in.readBytes(SIGNATURE.length);
-    boolean matched = Arrays.equals(signature, SIGNATURE);
-    if (!matched) {
-      throw new InvalidFormat(
-          in,
-          String.format(tag + " signature doesn't match expected signature: %s, expected %s",
-          DebugUtils.toByteArray(signature),
-          DebugUtils.toByteArray(SIGNATURE)));
-    }
-    return matched;
-  }
 }

core/src/com/riiablo/io/ByteInput.java

@@ -1,9 +1,11 @@
 package com.riiablo.io;
 
 import io.netty.buffer.ByteBuf;
+import io.netty.buffer.ByteBufUtil;
 import io.netty.buffer.Unpooled;
 import io.netty.util.CharsetUtil;
 import java.nio.charset.Charset;
+import java.util.Arrays;
 
 import com.riiablo.util.DebugUtils;
 
@@ -170,6 +172,47 @@ public class ByteInput {
     return this;
   }
 
+  /**
+   * Checks if the subsequent bytes match the specified sequence of bytes.
+   * If they do, they will be consumed by this method call, otherwise an
+   * {@link InvalidFormat} will be thrown and any bytes read by this method
+   * will be unread.
+   *
+   * @throws InvalidFormat if the next bytes do not match the specified
+   *    signature.
+   *
+   * @see InvalidFormat
+   * @see #skipUntil(byte[])
+   */
+  public ByteInput readSignature(byte[] signature) {
+    assert aligned() : "not aligned";
+    buffer.markReaderIndex();
+    if (buffer.readableBytes() < signature.length) {
+      final byte[] actual = new byte[buffer.readableBytes()];
+      buffer.readBytes(actual);
+      buffer.resetReaderIndex();
+      throw new InvalidFormat(
+          this,
+          String.format("Signatures do not match: %s, expected %s",
+              ByteBufUtil.hexDump(actual),
+              ByteBufUtil.hexDump(signature)));
+    }
+
+    final byte[] actual = new byte[signature.length];
+    buffer.readBytes(actual);
+    final boolean match = Arrays.equals(actual, signature);
+    if (!match) {
+      buffer.resetReaderIndex();
+      throw new InvalidFormat(
+          this,
+          String.format("Signatures do not match: %s, expected %s",
+              ByteBufUtil.hexDump(actual),
+              ByteBufUtil.hexDump(signature)));
+    }
+    incrementBitsRead((long) signature.length * Byte.SIZE);
+    return this;
+  }
+
   /**
    * Reads a slice of this buffer's sub-region starting at the current position
    * and increases the position by the size of the new slice (= numBytes).

core/src/com/riiablo/item/ItemSerializer.java

@@ -8,7 +8,6 @@ import com.riiablo.Riiablo;
 import com.riiablo.codec.excel.Gems;
 import com.riiablo.codec.util.BitStream;
 import com.riiablo.io.BitInput;
-import com.riiablo.io.BitUtils;
 import com.riiablo.io.ByteInput;
 import com.riiablo.log.Log;
 import com.riiablo.log.LogManager;
@@ -44,7 +43,8 @@ public class ItemSerializer {
     /** FIXME: workaround for {@link Item#loadFromStream(BitStream)} */
     final int itemOffset = in.bytesRead(); // TODO: remove when serialization implemented
     log.trace("Reading item...");
-    BitUtils.readSignature(in, SIGNATURE, log, "item");
+    log.trace("Validating item signature");
+    in.readSignature(SIGNATURE);
     Item item = new Item();
     item.reset();
     item.flags = in.read32();