clang-tools  8.0.0
RIFF.cpp
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1 //===--- RIFF.cpp - Binary container file format --------------------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #include "RIFF.h"
11 #include "llvm/Support/Endian.h"
12 
13 namespace clang {
14 namespace clangd {
15 namespace riff {
16 
17 static llvm::Error makeError(const char *Msg) {
18  return llvm::createStringError(llvm::inconvertibleErrorCode(), Msg);
19 }
20 
21 llvm::Expected<Chunk> readChunk(llvm::StringRef &Stream) {
22  if (Stream.size() < 8)
23  return makeError("incomplete chunk header");
24  Chunk C;
25  std::copy(Stream.begin(), Stream.begin() + 4, C.ID.begin());
26  Stream = Stream.drop_front(4);
27  uint32_t Len = llvm::support::endian::read32le(Stream.take_front(4).begin());
28  Stream = Stream.drop_front(4);
29  if (Stream.size() < Len)
30  return makeError("truncated chunk");
31  C.Data = Stream.take_front(Len);
32  Stream = Stream.drop_front(Len);
33  if (Len % 2 & !Stream.empty()) { // Skip padding byte.
34  if (Stream.front())
35  return makeError("nonzero padding byte");
36  Stream = Stream.drop_front();
37  }
38  return std::move(C);
39 }
40 
41 llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, const Chunk &C) {
42  OS.write(C.ID.data(), C.ID.size());
43  char Size[4];
44  llvm::support::endian::write32le(Size, C.Data.size());
45  OS.write(Size, sizeof(Size));
46  OS << C.Data;
47  if (C.Data.size() % 2)
48  OS.write(0);
49  return OS;
50 }
51 
52 llvm::Expected<File> readFile(llvm::StringRef Stream) {
53  auto RIFF = readChunk(Stream);
54  if (!RIFF)
55  return RIFF.takeError();
56  if (RIFF->ID != fourCC("RIFF"))
57  return makeError("not a RIFF container");
58  if (RIFF->Data.size() < 4)
59  return makeError("RIFF chunk too short");
60  File F;
61  std::copy(RIFF->Data.begin(), RIFF->Data.begin() + 4, F.Type.begin());
62  for (llvm::StringRef Body = RIFF->Data.drop_front(4); !Body.empty();)
63  if (auto Chunk = readChunk(Body)) {
64  F.Chunks.push_back(*Chunk);
65  } else
66  return Chunk.takeError();
67  return std::move(F);
68 }
69 
70 llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, const File &F) {
71  // To avoid copies, we serialize the outer RIFF chunk "by hand".
72  size_t DataLen = 4; // Predict length of RIFF chunk data.
73  for (const auto &C : F.Chunks)
74  DataLen += 4 + 4 + C.Data.size() + (C.Data.size() % 2);
75  OS << "RIFF";
76  char Size[4];
77  llvm::support::endian::write32le(Size, DataLen);
78  OS.write(Size, sizeof(Size));
79  OS.write(F.Type.data(), F.Type.size());
80  for (const auto &C : F.Chunks)
81  OS << C;
82  return OS;
83 }
84 
85 } // namespace riff
86 } // namespace clangd
87 } // namespace clang
llvm::StringRef Data
Definition: RIFF.h:51
static llvm::Error makeError(const char *Msg)
Definition: RIFF.cpp:17
constexpr FourCC fourCC(const char(&Literal)[5])
Definition: RIFF.h:45
llvm::Expected< File > readFile(llvm::StringRef Stream)
Definition: RIFF.cpp:52
std::vector< Chunk > Chunks
Definition: RIFF.h:59
llvm::Expected< Chunk > readChunk(llvm::StringRef &Stream)
Definition: RIFF.cpp:21
===– Representation.cpp - ClangDoc Representation --------—*- C++ -*-===//
llvm::raw_ostream & operator<<(llvm::raw_ostream &OS, const Chunk &C)
Definition: RIFF.cpp:41