clang-tools  11.0.0
RIFF.cpp
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1 //===--- RIFF.cpp - Binary container file format --------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "RIFF.h"
10 #include "llvm/Support/Endian.h"
11 #include "llvm/Support/Error.h"
12 
13 namespace clang {
14 namespace clangd {
15 namespace riff {
16 
17 static llvm::Error makeError(const llvm::Twine &Msg) {
18  return llvm::make_error<llvm::StringError>(Msg,
19  llvm::inconvertibleErrorCode());
20 }
21 
22 llvm::Expected<Chunk> readChunk(llvm::StringRef &Stream) {
23  if (Stream.size() < 8)
24  return makeError("incomplete chunk header: " + llvm::Twine(Stream.size()) +
25  " bytes available");
26  Chunk C;
27  std::copy(Stream.begin(), Stream.begin() + 4, C.ID.begin());
28  Stream = Stream.drop_front(4);
29  uint32_t Len = llvm::support::endian::read32le(Stream.take_front(4).begin());
30  Stream = Stream.drop_front(4);
31  if (Stream.size() < Len)
32  return makeError("truncated chunk: want " + llvm::Twine(Len) + ", got " +
33  llvm::Twine(Stream.size()));
34  C.Data = Stream.take_front(Len);
35  Stream = Stream.drop_front(Len);
36  if (Len % 2 & !Stream.empty()) { // Skip padding byte.
37  if (Stream.front())
38  return makeError("nonzero padding byte");
39  Stream = Stream.drop_front();
40  }
41  return std::move(C);
42 }
43 
44 llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, const Chunk &C) {
45  OS.write(C.ID.data(), C.ID.size());
46  char Size[4];
47  llvm::support::endian::write32le(Size, C.Data.size());
48  OS.write(Size, sizeof(Size));
49  OS << C.Data;
50  if (C.Data.size() % 2)
51  OS.write(0);
52  return OS;
53 }
54 
55 llvm::Expected<File> readFile(llvm::StringRef Stream) {
56  auto RIFF = readChunk(Stream);
57  if (!RIFF)
58  return RIFF.takeError();
59  if (RIFF->ID != fourCC("RIFF"))
60  return makeError("not a RIFF container: root is " + fourCCStr(RIFF->ID));
61  if (RIFF->Data.size() < 4)
62  return makeError("RIFF chunk too short");
63  File F;
64  std::copy(RIFF->Data.begin(), RIFF->Data.begin() + 4, F.Type.begin());
65  for (llvm::StringRef Body = RIFF->Data.drop_front(4); !Body.empty();)
66  if (auto Chunk = readChunk(Body)) {
67  F.Chunks.push_back(*Chunk);
68  } else
69  return Chunk.takeError();
70  return std::move(F);
71 }
72 
73 llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, const File &F) {
74  // To avoid copies, we serialize the outer RIFF chunk "by hand".
75  size_t DataLen = 4; // Predict length of RIFF chunk data.
76  for (const auto &C : F.Chunks)
77  DataLen += 4 + 4 + C.Data.size() + (C.Data.size() % 2);
78  OS << "RIFF";
79  char Size[4];
80  llvm::support::endian::write32le(Size, DataLen);
81  OS.write(Size, sizeof(Size));
82  OS.write(F.Type.data(), F.Type.size());
83  for (const auto &C : F.Chunks)
84  OS << C;
85  return OS;
86 }
87 
88 } // namespace riff
89 } // namespace clangd
90 } // namespace clang
clang::clangd::riff::Chunk
Definition: RIFF.h:51
clang::clangd::riff::fourCC
constexpr FourCC fourCC(const char(&Literal)[5])
Definition: RIFF.h:44
clang::clangd::riff::Chunk::ID
FourCC ID
Definition: RIFF.h:52
clang::clangd::IndexFileFormat::RIFF
clang::clangd::riff::operator<<
llvm::raw_ostream & operator<<(llvm::raw_ostream &OS, const Chunk &C)
Definition: RIFF.cpp:44
clang::clangd::riff::readChunk
llvm::Expected< Chunk > readChunk(llvm::StringRef &Stream)
Definition: RIFF.cpp:22
clang::clangd::riff::fourCCStr
constexpr llvm::StringRef fourCCStr(const FourCC &Data)
Definition: RIFF.h:47
clang::clangd::riff::Chunk::Data
llvm::StringRef Data
Definition: RIFF.h:53
RIFF.h
clang::clangd::riff::readFile
llvm::Expected< File > readFile(llvm::StringRef Stream)
Definition: RIFF.cpp:55
clang::clangd::riff::File
Definition: RIFF.h:59
clang
===– Representation.cpp - ClangDoc Representation --------—*- C++ -*-===//
Definition: ApplyReplacements.h:27
OS
llvm::raw_string_ostream OS
Definition: TraceTests.cpp:162
clang::clangd::riff::makeError
static llvm::Error makeError(const llvm::Twine &Msg)
Definition: RIFF.cpp:17
clang::clangd::MessageType::Error
An error message.