1 files changed, 166 insertions, 0 deletions
diff --git a/include/llvm/Support/BinaryStreamWriter.h b/include/llvm/Support/BinaryStreamWriter.h
new file mode 100644
index 000000000000..64f26b24543d
--- /dev/null
+++ b/include/llvm/Support/BinaryStreamWriter.h
@@ -0,0 +1,166 @@
+//===- BinaryStreamWriter.h - Writes objects to a BinaryStream ---*- C++-*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_SUPPORT_BINARYSTREAMWRITER_H
+#define LLVM_SUPPORT_BINARYSTREAMWRITER_H
+
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Support/BinaryStreamArray.h"
+#include "llvm/Support/BinaryStreamError.h"
+#include "llvm/Support/BinaryStreamRef.h"
+#include "llvm/Support/Endian.h"
+#include "llvm/Support/Error.h"
+#include <cstdint>
+#include <type_traits>
+
+namespace llvm {
+
+/// \brief Provides write only access to a subclass of `WritableBinaryStream`.
+/// Provides bounds checking and helpers for writing certain common data types
+/// such as null-terminated strings, integers in various flavors of endianness,
+/// etc.  Can be subclassed to provide reading and writing of custom datatypes,
+/// although no methods are overridable.
+class BinaryStreamWriter {
+public:
+  BinaryStreamWriter() = default;
+  explicit BinaryStreamWriter(WritableBinaryStreamRef Stream);
+  virtual ~BinaryStreamWriter() {}
+
+  /// Write the bytes specified in \p Buffer to the underlying stream.
+  /// On success, updates the offset so that subsequent writes will occur
+  /// at the next unwritten position.
+  ///
+  /// \returns a success error code if the data was successfully written,
+  /// otherwise returns an appropriate error code.
+  Error writeBytes(ArrayRef<uint8_t> Buffer);
+
+  /// Write the the integer \p Value to the underlying stream in the
+  /// specified endianness.  On success, updates the offset so that
+  /// subsequent writes occur at the next unwritten position.
+  ///
+  /// \returns a success error code if the data was successfully written,
+  /// otherwise returns an appropriate error code.
+  template <typename T> Error writeInteger(T Value) {
+    static_assert(std::is_integral<T>::value,
+                  "Cannot call writeInteger with non-integral value!");
+    uint8_t Buffer[sizeof(T)];
+    llvm::support::endian::write<T, llvm::support::unaligned>(
+        Buffer, Value, Stream.getEndian());
+    return writeBytes(Buffer);
+  }
+
+  /// Similar to writeInteger
+  template <typename T> Error writeEnum(T Num) {
+    static_assert(std::is_enum<T>::value,
+                  "Cannot call writeEnum with non-Enum type");
+
+    using U = typename std::underlying_type<T>::type;
+    return writeInteger<U>(static_cast<U>(Num));
+  }
+
+  /// Write the the string \p Str to the underlying stream followed by a null
+  /// terminator.  On success, updates the offset so that subsequent writes
+  /// occur at the next unwritten position.  \p Str need not be null terminated
+  /// on input.
+  ///
+  /// \returns a success error code if the data was successfully written,
+  /// otherwise returns an appropriate error code.
+  Error writeCString(StringRef Str);
+
+  /// Write the the string \p Str to the underlying stream without a null
+  /// terminator.  On success, updates the offset so that subsequent writes
+  /// occur at the next unwritten position.
+  ///
+  /// \returns a success error code if the data was successfully written,
+  /// otherwise returns an appropriate error code.
+  Error writeFixedString(StringRef Str);
+
+  /// Efficiently reads all data from \p Ref, and writes it to this stream.
+  /// This operation will not invoke any copies of the source data, regardless
+  /// of the source stream's implementation.
+  ///
+  /// \returns a success error code if the data was successfully written,
+  /// otherwise returns an appropriate error code.
+  Error writeStreamRef(BinaryStreamRef Ref);
+
+  /// Efficiently reads \p Size bytes from \p Ref, and writes it to this stream.
+  /// This operation will not invoke any copies of the source data, regardless
+  /// of the source stream's implementation.
+  ///
+  /// \returns a success error code if the data was successfully written,
+  /// otherwise returns an appropriate error code.
+  Error writeStreamRef(BinaryStreamRef Ref, uint32_t Size);
+
+  /// Writes the object \p Obj to the underlying stream, as if by using memcpy.
+  /// It is up to the caller to ensure that type of \p Obj can be safely copied
+  /// in this fashion, as no checks are made to ensure that this is safe.
+  ///
+  /// \returns a success error code if the data was successfully written,
+  /// otherwise returns an appropriate error code.
+  template <typename T> Error writeObject(const T &Obj) {
+    static_assert(!std::is_pointer<T>::value,
+                  "writeObject should not be used with pointers, to write "
+                  "the pointed-to value dereference the pointer before calling "
+                  "writeObject");
+    return writeBytes(
+        ArrayRef<uint8_t>(reinterpret_cast<const uint8_t *>(&Obj), sizeof(T)));
+  }
+
+  /// Writes an array of objects of type T to the underlying stream, as if by
+  /// using memcpy.  It is up to the caller to ensure that type of \p Obj can
+  /// be safely copied in this fashion, as no checks are made to ensure that
+  /// this is safe.
+  ///
+  /// \returns a success error code if the data was successfully written,
+  /// otherwise returns an appropriate error code.
+  template <typename T> Error writeArray(ArrayRef<T> Array) {
+    if (Array.empty())
+      return Error::success();
+    if (Array.size() > UINT32_MAX / sizeof(T))
+      return make_error<BinaryStreamError>(
+          stream_error_code::invalid_array_size);
+
+    return writeBytes(
+        ArrayRef<uint8_t>(reinterpret_cast<const uint8_t *>(Array.data()),
+                          Array.size() * sizeof(T)));
+  }
+
+  /// Writes all data from the array \p Array to the underlying stream.
+  ///
+  /// \returns a success error code if the data was successfully written,
+  /// otherwise returns an appropriate error code.
+  template <typename T, typename U>
+  Error writeArray(VarStreamArray<T, U> Array) {
+    return writeStreamRef(Array.getUnderlyingStream());
+  }
+
+  /// Writes all elements from the array \p Array to the underlying stream.
+  ///
+  /// \returns a success error code if the data was successfully written,
+  /// otherwise returns an appropriate error code.
+  template <typename T> Error writeArray(FixedStreamArray<T> Array) {
+    return writeStreamRef(Array.getUnderlyingStream());
+  }
+
+  void setOffset(uint32_t Off) { Offset = Off; }
+  uint32_t getOffset() const { return Offset; }
+  uint32_t getLength() const { return Stream.getLength(); }
+  uint32_t bytesRemaining() const { return getLength() - getOffset(); }
+  Error padToAlignment(uint32_t Align);
+
+protected:
+  WritableBinaryStreamRef Stream;
+  uint32_t Offset = 0;
+};
+
+} // end namespace llvm
+
+#endif // LLVM_SUPPORT_BINARYSTREAMWRITER_H