1 files changed, 24 insertions, 4 deletions
diff --git a/include/llvm/Support/BinaryStreamReader.h b/include/llvm/Support/BinaryStreamReader.h
index f30d82d81b25..77738077f5ff 100644
--- a/include/llvm/Support/BinaryStreamReader.h
+++ b/include/llvm/Support/BinaryStreamReader.h
@@ -31,6 +31,7 @@ namespace llvm {
 /// are overridable.
 class BinaryStreamReader {
 public:
+  BinaryStreamReader() = default;
   explicit BinaryStreamReader(BinaryStreamRef Stream);
   virtual ~BinaryStreamReader() {}
 
@@ -172,13 +173,29 @@ public:
   /// \returns a success error code if the data was successfully read, otherwise
   /// returns an appropriate error code.
   template <typename T, typename U>
-  Error
-  readArray(VarStreamArray<T, U> &Array, uint32_t Size,
-            typename VarStreamArray<T, U>::ContextType *Context = nullptr) {
+  Error readArray(VarStreamArray<T, U> &Array, uint32_t Size) {
     BinaryStreamRef S;
     if (auto EC = readStreamRef(S, Size))
       return EC;
-    Array = VarStreamArray<T, U>(S, Context);
+    Array = VarStreamArray<T, U>(S);
+    return Error::success();
+  }
+
+  /// Read a VarStreamArray of size \p Size bytes and store the result into
+  /// \p Array.  Updates the stream's offset to point after the newly read
+  /// array.  Never causes a copy (although iterating the elements of the
+  /// VarStreamArray may, depending upon the implementation of the underlying
+  /// stream).
+  ///
+  /// \returns a success error code if the data was successfully read, otherwise
+  /// returns an appropriate error code.
+  template <typename T, typename U, typename ContextType>
+  Error readArray(VarStreamArray<T, U> &Array, uint32_t Size,
+                  ContextType &&Context) {
+    BinaryStreamRef S;
+    if (auto EC = readStreamRef(S, Size))
+      return EC;
+    Array = VarStreamArray<T, U>(S, std::move(Context));
     return Error::success();
   }
 
@@ -227,6 +244,9 @@ public:
   /// \returns the next byte in the stream.
   uint8_t peek() const;
 
+  std::pair<BinaryStreamReader, BinaryStreamReader>
+  split(uint32_t Offset) const;
+
 private:
   BinaryStreamRef Stream;
   uint32_t Offset;