forked from OSchip/llvm-project
87 lines
2.7 KiB
C++
87 lines
2.7 KiB
C++
//===--- RIFF.cpp - Binary container file format --------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "RIFF.h"
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#include "llvm/Support/Endian.h"
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namespace clang {
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namespace clangd {
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namespace riff {
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static llvm::Error makeError(const char *Msg) {
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return llvm::createStringError(llvm::inconvertibleErrorCode(), Msg);
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}
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llvm::Expected<Chunk> readChunk(llvm::StringRef &Stream) {
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if (Stream.size() < 8)
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return makeError("incomplete chunk header");
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Chunk C;
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std::copy(Stream.begin(), Stream.begin() + 4, C.ID.begin());
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Stream = Stream.drop_front(4);
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uint32_t Len = llvm::support::endian::read32le(Stream.take_front(4).begin());
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Stream = Stream.drop_front(4);
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if (Stream.size() < Len)
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return makeError("truncated chunk");
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C.Data = Stream.take_front(Len);
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Stream = Stream.drop_front(Len);
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if (Len % 2 & !Stream.empty()) { // Skip padding byte.
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if (Stream.front())
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return makeError("nonzero padding byte");
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Stream = Stream.drop_front();
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}
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return std::move(C);
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}
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llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, const Chunk &C) {
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OS.write(C.ID.data(), C.ID.size());
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char Size[4];
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llvm::support::endian::write32le(Size, C.Data.size());
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OS.write(Size, sizeof(Size));
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OS << C.Data;
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if (C.Data.size() % 2)
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OS.write(0);
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return OS;
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}
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llvm::Expected<File> readFile(llvm::StringRef Stream) {
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auto RIFF = readChunk(Stream);
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if (!RIFF)
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return RIFF.takeError();
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if (RIFF->ID != fourCC("RIFF"))
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return makeError("not a RIFF container");
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if (RIFF->Data.size() < 4)
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return makeError("RIFF chunk too short");
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File F;
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std::copy(RIFF->Data.begin(), RIFF->Data.begin() + 4, F.Type.begin());
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for (llvm::StringRef Body = RIFF->Data.drop_front(4); !Body.empty();)
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if (auto Chunk = readChunk(Body)) {
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F.Chunks.push_back(*Chunk);
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} else
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return Chunk.takeError();
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return std::move(F);
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}
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llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, const File &F) {
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// To avoid copies, we serialize the outer RIFF chunk "by hand".
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size_t DataLen = 4; // Predict length of RIFF chunk data.
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for (const auto &C : F.Chunks)
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DataLen += 4 + 4 + C.Data.size() + (C.Data.size() % 2);
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OS << "RIFF";
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char Size[4];
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llvm::support::endian::write32le(Size, DataLen);
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OS.write(Size, sizeof(Size));
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OS.write(F.Type.data(), F.Type.size());
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for (const auto &C : F.Chunks)
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OS << C;
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return OS;
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}
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} // namespace riff
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} // namespace clangd
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} // namespace clang
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