1 files changed, 88 insertions, 0 deletions
diff --git a/clang-tools-extra/clangd/RIFF.cpp b/clang-tools-extra/clangd/RIFF.cpp
new file mode 100644
index 00000000000..cb832db87f9
--- /dev/null
+++ b/clang-tools-extra/clangd/RIFF.cpp
@@ -0,0 +1,88 @@
+//===--- RIFF.cpp - Binary container file format --------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "RIFF.h"
+#include "llvm/Support/Endian.h"
+
+using namespace llvm;
+namespace clang {
+namespace clangd {
+namespace riff {
+
+static Error makeError(const char *Msg) {
+  return createStringError(inconvertibleErrorCode(), Msg);
+}
+
+Expected<Chunk> readChunk(StringRef &Stream) {
+  if (Stream.size() < 8)
+    return makeError("incomplete chunk header");
+  Chunk C;
+  std::copy(Stream.begin(), Stream.begin() + 4, C.ID.begin());
+  Stream = Stream.drop_front(4);
+  uint32_t Len = support::endian::read32le(Stream.take_front(4).begin());
+  Stream = Stream.drop_front(4);
+  if (Stream.size() < Len)
+    return makeError("truncated chunk");
+  C.Data = Stream.take_front(Len);
+  Stream = Stream.drop_front(Len);
+  if (Len % 2 & !Stream.empty()) { // Skip padding byte.
+    if (Stream.front())
+      return makeError("nonzero padding byte");
+    Stream = Stream.drop_front();
+  }
+  return C;
+};
+
+raw_ostream &operator<<(raw_ostream &OS, const Chunk &C) {
+  OS.write(C.ID.begin(), C.ID.size());
+  char Size[4];
+  llvm::support::endian::write32le(Size, C.Data.size());
+  OS.write(Size, sizeof(Size));
+  OS << C.Data;
+  if (C.Data.size() % 2)
+    OS.write(0);
+  return OS;
+}
+
+llvm::Expected<File> readFile(llvm::StringRef Stream) {
+  auto RIFF = readChunk(Stream);
+  if (!RIFF)
+    return RIFF.takeError();
+  if (RIFF->ID != fourCC("RIFF"))
+    return makeError("not a RIFF container");
+  if (RIFF->Data.size() < 4)
+    return makeError("RIFF chunk too short");
+  File F;
+  std::copy(RIFF->Data.begin(), RIFF->Data.begin() + 4, F.Type.begin());
+  for (llvm::StringRef Body = RIFF->Data.drop_front(4); !Body.empty();)
+    if (auto Chunk = readChunk(Body)) {
+      F.Chunks.push_back(*Chunk);
+    } else
+      return Chunk.takeError();
+  return F;
+}
+
+raw_ostream &operator<<(raw_ostream &OS, const File &F) {
+  // To avoid copies, we serialize the outer RIFF chunk "by hand".
+  size_t DataLen = 4; // Predict length of RIFF chunk data.
+  for (const auto &C : F.Chunks)
+    DataLen += 4 + 4 + C.Data.size() + (C.Data.size() % 2);
+  OS << "RIFF";
+  char Size[4];
+  llvm::support::endian::write32le(Size, DataLen);
+  OS.write(Size, sizeof(Size));
+  OS.write(F.Type.begin(), F.Type.size());
+  for (const auto &C : F.Chunks)
+    OS << C;
+  return OS;
+}
+
+} // namespace riff
+} // namespace clangd
+} // namespace clang