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//===--- 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"
namespace clang {
namespace clangd {
namespace riff {
static llvm::Error makeError(const char *Msg) {
return llvm::createStringError(llvm::inconvertibleErrorCode(), Msg);
}
llvm::Expected<Chunk> readChunk(llvm::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 = llvm::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 std::move(C);
}
llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, const Chunk &C) {
OS.write(C.ID.data(), 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 std::move(F);
}
llvm::raw_ostream &operator<<(llvm::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.data(), F.Type.size());
for (const auto &C : F.Chunks)
OS << C;
return OS;
}
} // namespace riff
} // namespace clangd
} // namespace clang
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