84 lines · cpp
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-exception6//7//===----------------------------------------------------------------------===//8 9#include "RIFF.h"10#include "support/Logger.h"11#include "llvm/Support/Endian.h"12 13namespace clang {14namespace clangd {15namespace riff {16 17llvm::Expected<Chunk> readChunk(llvm::StringRef &Stream) {18 if (Stream.size() < 8)19 return error("incomplete chunk header: {0} bytes available", Stream.size());20 Chunk C;21 std::copy(Stream.begin(), Stream.begin() + 4, C.ID.begin());22 Stream = Stream.drop_front(4);23 uint32_t Len = llvm::support::endian::read32le(Stream.take_front(4).begin());24 Stream = Stream.drop_front(4);25 if (Stream.size() < Len)26 return error("truncated chunk: want {0}, got {1}", Len, Stream.size());27 C.Data = Stream.take_front(Len);28 Stream = Stream.drop_front(Len);29 if ((Len % 2) && !Stream.empty()) { // Skip padding byte.30 if (Stream.front())31 return error("nonzero padding byte");32 Stream = Stream.drop_front();33 }34 return std::move(C);35}36 37llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, const Chunk &C) {38 OS.write(C.ID.data(), C.ID.size());39 char Size[4];40 llvm::support::endian::write32le(Size, C.Data.size());41 OS.write(Size, sizeof(Size));42 OS << C.Data;43 if (C.Data.size() % 2)44 OS.write(0);45 return OS;46}47 48llvm::Expected<File> readFile(llvm::StringRef Stream) {49 auto RIFF = readChunk(Stream);50 if (!RIFF)51 return RIFF.takeError();52 if (RIFF->ID != fourCC("RIFF"))53 return error("not a RIFF container: root is {0}", fourCCStr(RIFF->ID));54 if (RIFF->Data.size() < 4)55 return error("RIFF chunk too short");56 File F;57 std::copy(RIFF->Data.begin(), RIFF->Data.begin() + 4, F.Type.begin());58 for (llvm::StringRef Body = RIFF->Data.drop_front(4); !Body.empty();)59 if (auto Chunk = readChunk(Body)) {60 F.Chunks.push_back(*Chunk);61 } else62 return Chunk.takeError();63 return std::move(F);64}65 66llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, const File &F) {67 // To avoid copies, we serialize the outer RIFF chunk "by hand".68 size_t DataLen = 4; // Predict length of RIFF chunk data.69 for (const auto &C : F.Chunks)70 DataLen += 4 + 4 + C.Data.size() + (C.Data.size() % 2);71 OS << "RIFF";72 char Size[4];73 llvm::support::endian::write32le(Size, DataLen);74 OS.write(Size, sizeof(Size));75 OS.write(F.Type.data(), F.Type.size());76 for (const auto &C : F.Chunks)77 OS << C;78 return OS;79}80 81} // namespace riff82} // namespace clangd83} // namespace clang84