From cafe8679b410ec98abd2986f3f19afc4edd347a1 Mon Sep 17 00:00:00 2001
From: Collin Smith <collinsmith70@gmail.com>
Date: Wed, 12 Aug 2020 17:22:55 -0700
Subject: [PATCH] Added support for marking read position for debugging

---
 core/src/com/riiablo/io/BitInput.java      |  2 ++
 core/src/com/riiablo/io/ByteInput.java     | 25 ++++++++++++++++++++--
 core/src/com/riiablo/io/InvalidFormat.java |  4 ++--
 3 files changed, 27 insertions(+), 4 deletions(-)

diff --git a/core/src/com/riiablo/io/BitInput.java b/core/src/com/riiablo/io/BitInput.java
index 70da63cd..0fa57779 100644
--- a/core/src/com/riiablo/io/BitInput.java
+++ b/core/src/com/riiablo/io/BitInput.java
@@ -172,6 +172,7 @@ public class BitInput {
   }
 
   long incrementBitsRead(long bits) {
+    byteInput.updateMark();
     if ((bitsRead += bits) > numBits) {
       bitsRead = numBits;
       throw new EndOfInput();
@@ -181,6 +182,7 @@ public class BitInput {
   }
 
   long decrementBitsRead(long bits) {
+    byteInput.updateMark();
     if ((bitsRead -= bits) < 0) {
       assert false : "bitsRead(" + bitsRead + ") < " + 0;
       bitsRead = 0;
diff --git a/core/src/com/riiablo/io/ByteInput.java b/core/src/com/riiablo/io/ByteInput.java
index 81747935..db860dec 100644
--- a/core/src/com/riiablo/io/ByteInput.java
+++ b/core/src/com/riiablo/io/ByteInput.java
@@ -28,11 +28,27 @@ public class ByteInput {
   }
 
   private final ByteBuf buffer;
+  private final int offset;
+  private int mark;
   private BitInput bitInput;
 
   ByteInput(ByteBuf buffer) {
+    this(buffer, 0);
+  }
+
+  ByteInput(ByteBuf buffer, int offset) {
     assert buffer.isReadOnly() : "buffer should be tagged ByteBuf#asReadOnly()";
     this.buffer = buffer;
+    this.offset = offset;
+    updateMark();
+  }
+
+  int updateMark() {
+    return mark = offset + buffer.readerIndex();
+  }
+
+  public int mark() {
+    return mark;
   }
 
   /**
@@ -151,8 +167,10 @@ public class ByteInput {
    */
   public ByteInput readSlice(long numBytes) {
     assert numBytes <= Integer.MAX_VALUE : "ByteBuf only supports int length";
+    final int mark = updateMark(); // updates mark to start offset of slice
     final ByteBuf slice = buffer.readSlice((int) numBytes);
-    return new ByteInput(slice);
+    updateMark(); // updates mark to end position of slice
+    return new ByteInput(slice, mark);
   }
 
   /**
@@ -169,6 +187,7 @@ public class ByteInput {
   }
 
   long incrementBitsRead(long bits) {
+    updateMark();
     assert (bits & (Byte.SIZE - 1)) == 0;
     if (bitInput == null) return 0;
     return bitInput.incrementBitsRead(bits);
@@ -177,7 +196,9 @@ public class ByteInput {
   long decrementBitsRead(long bits) {
     assert (bits & (Byte.SIZE - 1)) == 0;
     if (bitInput == null) return 0;
-    return bitInput.decrementBitsRead(bits);
+    long bitsRead = bitInput.decrementBitsRead(bits);
+    assert mark == buffer.readerIndex() : "mark(" + mark + ") != buffer.readerIndex(" + buffer.readerIndex() + ")";
+    return bitsRead;
   }
 
   /**
diff --git a/core/src/com/riiablo/io/InvalidFormat.java b/core/src/com/riiablo/io/InvalidFormat.java
index 0f38d4bc..935273b0 100644
--- a/core/src/com/riiablo/io/InvalidFormat.java
+++ b/core/src/com/riiablo/io/InvalidFormat.java
@@ -12,8 +12,8 @@ public class InvalidFormat extends RuntimeException {
   }
 
   public InvalidFormat(ByteInput in, String message, Throwable cause) {
-    super(message + " @0x" + Integer.toHexString(in.bytesRead()), cause);
-    this.offset = in.bytesRead();
+    super(message + " +0x" + Integer.toHexString(in.mark()), cause);
+    this.offset = in.mark();
   }
 
   @Deprecated