From beff6d3f6d8f96a98cf7d7c6d39f0946f0027d8c Mon Sep 17 00:00:00 2001
From: William Burns <mudokonman@gmail.com>
Date: Mon, 8 May 2023 08:19:32 -0700
Subject: [PATCH] review comments

---
 .../protostream/impl/TagReaderImpl.java       | 43 +++++++++++++++----
 1 file changed, 34 insertions(+), 9 deletions(-)

diff --git a/core/src/main/java/org/infinispan/protostream/impl/TagReaderImpl.java b/core/src/main/java/org/infinispan/protostream/impl/TagReaderImpl.java
index 5c1801da2..5a3585cea 100644
--- a/core/src/main/java/org/infinispan/protostream/impl/TagReaderImpl.java
+++ b/core/src/main/java/org/infinispan/protostream/impl/TagReaderImpl.java
@@ -870,9 +870,7 @@ String readString() throws IOException {
          int length = readVarint32();
          if (length > 0 && length <= limit - pos) {
             byte[] bytes = readRawByteArray(length);
-            String value = new String(bytes, 0, length, UTF8);
-            pos += length;
-            return value;
+            return new String(bytes, 0, length, UTF8);
          }
          if (length == 0) {
             return "";
@@ -885,6 +883,9 @@ String readString() throws IOException {
 
       @Override
       ByteBuffer readRawByteBuffer(int length) throws IOException {
+         if (length == 0) {
+            return EMPTY_BUFFER;
+         }
          byte[] bytes = readRawByteArray(length);
          return ByteBuffer.wrap(bytes);
       }
@@ -1046,9 +1047,16 @@ byte[] readRawByteArray(int length) throws IOException {
             if (pos > globalLimit) {
                throw log.globalLimitExceeded();
             }
+            int readTotal = 0;
+            int readAmount;
             byte[] array = new byte[length];
-            int readAmount = in.read(array);
-            if (readAmount != length) {
+            while ((readAmount = in.read(array, readTotal, length - readTotal)) != -1) {
+               readTotal += readAmount;
+               if (readTotal == length) {
+                  break;
+               }
+            }
+            if (readTotal != length) {
                throw log.messageTruncated();
             }
             return array;
@@ -1066,10 +1074,7 @@ byte[] readRawByteArray(int length) throws IOException {
       protected void skipRawBytes(int length) throws IOException {
          if (length <= limit - pos && length >= 0) {
             pos += length;
-            long skipAmount = in.skip(length);
-            if (skipAmount != length) {
-               throw log.messageTruncated();
-            }
+            skipNBytes(length);
          } else {
             if (length < 0) {
                throw log.negativeLength();
@@ -1077,6 +1082,26 @@ protected void skipRawBytes(int length) throws IOException {
             throw log.messageTruncated();
          }
       }
+
+      // Copied from InputStream, we can't use Java 12 or newer just yet, can be removed when on a newer version.
+      private void skipNBytes(long n) throws IOException {
+         while (n > 0) {
+            long ns = in.skip(n);
+            if (ns > 0 && ns <= n) {
+               // adjust number to skip
+               n -= ns;
+            } else if (ns == 0) { // no bytes skipped
+               // read one byte to check for EOS
+               if (in.read() == -1) {
+                  throw log.messageTruncated();
+               }
+               // one byte read so decrement number to skip
+               n--;
+            } else { // skipped negative or too many bytes
+               throw new IOException("Unable to skip exactly");
+            }
+         }
+      }
    }
 
 }