clang-tools  10.0.0git
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 
12 namespace clang {
13 namespace clangd {
14 namespace riff {
15 
16 static llvm::Error makeError(const char *Msg) {
17  return llvm::createStringError(llvm::inconvertibleErrorCode(), Msg);
18 }
19 
20 llvm::Expected<Chunk> readChunk(llvm::StringRef &Stream) {
21  if (Stream.size() < 8)
22  return makeError("incomplete chunk header");
23  Chunk C;
24  std::copy(Stream.begin(), Stream.begin() + 4, C.ID.begin());
25  Stream = Stream.drop_front(4);
26  uint32_t Len = llvm::support::endian::read32le(Stream.take_front(4).begin());
27  Stream = Stream.drop_front(4);
28  if (Stream.size() < Len)
29  return makeError("truncated chunk");
30  C.Data = Stream.take_front(Len);
31  Stream = Stream.drop_front(Len);
32  if (Len % 2 & !Stream.empty()) { // Skip padding byte.
33  if (Stream.front())
34  return makeError("nonzero padding byte");
35  Stream = Stream.drop_front();
36  }
37  return std::move(C);
38 }
39 
40 llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, const Chunk &C) {
41  OS.write(C.ID.data(), C.ID.size());
42  char Size[4];
43  llvm::support::endian::write32le(Size, C.Data.size());
44  OS.write(Size, sizeof(Size));
45  OS << C.Data;
46  if (C.Data.size() % 2)
47  OS.write(0);
48  return OS;
49 }
50 
51 llvm::Expected<File> readFile(llvm::StringRef Stream) {
52  auto RIFF = readChunk(Stream);
53  if (!RIFF)
54  return RIFF.takeError();
55  if (RIFF->ID != fourCC("RIFF"))
56  return makeError("not a RIFF container");
57  if (RIFF->Data.size() < 4)
58  return makeError("RIFF chunk too short");
59  File F;
60  std::copy(RIFF->Data.begin(), RIFF->Data.begin() + 4, F.Type.begin());
61  for (llvm::StringRef Body = RIFF->Data.drop_front(4); !Body.empty();)
62  if (auto Chunk = readChunk(Body)) {
63  F.Chunks.push_back(*Chunk);
64  } else
65  return Chunk.takeError();
66  return std::move(F);
67 }
68 
69 llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, const File &F) {
70  // To avoid copies, we serialize the outer RIFF chunk "by hand".
71  size_t DataLen = 4; // Predict length of RIFF chunk data.
72  for (const auto &C : F.Chunks)
73  DataLen += 4 + 4 + C.Data.size() + (C.Data.size() % 2);
74  OS << "RIFF";
75  char Size[4];
76  llvm::support::endian::write32le(Size, DataLen);
77  OS.write(Size, sizeof(Size));
78  OS.write(F.Type.data(), F.Type.size());
79  for (const auto &C : F.Chunks)
80  OS << C;
81  return OS;
82 }
83 
84 } // namespace riff
85 } // namespace clangd
86 } // namespace clang
llvm::StringRef Data
Definition: RIFF.h:50
static llvm::Error makeError(const char *Msg)
Definition: RIFF.cpp:16
constexpr FourCC fourCC(const char(&Literal)[5])
Definition: RIFF.h:44
llvm::Expected< File > readFile(llvm::StringRef Stream)
Definition: RIFF.cpp:51
std::vector< Chunk > Chunks
Definition: RIFF.h:58
llvm::Expected< Chunk > readChunk(llvm::StringRef &Stream)
Definition: RIFF.cpp:20
===– Representation.cpp - ClangDoc Representation --------—*- C++ -*-===//
llvm::raw_ostream & operator<<(llvm::raw_ostream &OS, const Chunk &C)
Definition: RIFF.cpp:40