Merge pull request #7 from AurorNZ/revert-6-revert-5-fix-div-by-zero

Fix div-by-zero errors on files which don't have any changed content
AurorNZ · Dec 7, 2020 · f917372 · f917372
2 parents bfcfb18 + eff6652
commit f917372
Showing 1 changed file with 12 additions and 6 deletions.
diff --git a/src/Squirrel/BinaryPatchUtility.cs b/src/Squirrel/BinaryPatchUtility.cs
@@ -230,21 +230,27 @@ static void CreateInternal(byte[] oldData, byte[] newData, Stream output)
             WriteInt64(controlEndPosition - startPosition - c_headerSize, header, 8);
 
             // write compressed diff data
-            using (WrappingStream wrappingStream = new WrappingStream(output, Ownership.None))
-            using (var bz2Stream = new BZip2Stream(wrappingStream, CompressionMode.Compress))
+            if (dblen > 0)
             {
-                bz2Stream.Write(db, 0, dblen);
+                using (WrappingStream wrappingStream = new WrappingStream(output, Ownership.None))
+                using (var bz2Stream = new BZip2Stream(wrappingStream, CompressionMode.Compress))
+                {
+                    bz2Stream.Write(db, 0, dblen);
+                }
             }
 
             // compute size of compressed diff data
             long diffEndPosition = output.Position;
             WriteInt64(diffEndPosition - controlEndPosition, header, 16);
 
             // write compressed extra data
-            using (WrappingStream wrappingStream = new WrappingStream(output, Ownership.None))
-            using (var bz2Stream = new BZip2Stream(wrappingStream, CompressionMode.Compress))
+            if (eblen > 0)
             {
-                bz2Stream.Write(eb, 0, eblen);
+                using (WrappingStream wrappingStream = new WrappingStream(output, Ownership.None))
+                using (var bz2Stream = new BZip2Stream(wrappingStream, CompressionMode.Compress))
+                {
+                    bz2Stream.Write(eb, 0, eblen);
+                }
             }
 
             // seek to the beginning, write the header, then seek back to end