1 //===- BinaryStreamWriter.cpp - Writes objects to a BinaryStream ----------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 10 #include "llvm/Support/BinaryStreamWriter.h" 11 12 #include "llvm/Support/BinaryStreamError.h" 13 #include "llvm/Support/BinaryStreamReader.h" 14 #include "llvm/Support/BinaryStreamRef.h" 15 16 using namespace llvm; 17 18 BinaryStreamWriter::BinaryStreamWriter(WritableBinaryStreamRef Ref) 19 : Stream(Ref) {} 20 21 BinaryStreamWriter::BinaryStreamWriter(WritableBinaryStream &Stream) 22 : Stream(Stream) {} 23 24 BinaryStreamWriter::BinaryStreamWriter(MutableArrayRef<uint8_t> Data, 25 llvm::support::endianness Endian) 26 : Stream(Data, Endian) {} 27 28 Error BinaryStreamWriter::writeBytes(ArrayRef<uint8_t> Buffer) { 29 if (auto EC = Stream.writeBytes(Offset, Buffer)) 30 return EC; 31 Offset += Buffer.size(); 32 return Error::success(); 33 } 34 35 Error BinaryStreamWriter::writeCString(StringRef Str) { 36 if (auto EC = writeFixedString(Str)) 37 return EC; 38 if (auto EC = writeObject('\0')) 39 return EC; 40 41 return Error::success(); 42 } 43 44 Error BinaryStreamWriter::writeFixedString(StringRef Str) { 45 46 return writeBytes(arrayRefFromStringRef(Str)); 47 } 48 49 Error BinaryStreamWriter::writeStreamRef(BinaryStreamRef Ref) { 50 return writeStreamRef(Ref, Ref.getLength()); 51 } 52 53 Error BinaryStreamWriter::writeStreamRef(BinaryStreamRef Ref, uint32_t Length) { 54 BinaryStreamReader SrcReader(Ref.slice(0, Length)); 55 // This is a bit tricky. If we just call readBytes, we are requiring that it 56 // return us the entire stream as a contiguous buffer. There is no guarantee 57 // this can be satisfied by returning a reference straight from the buffer, as 58 // an implementation may not store all data in a single contiguous buffer. So 59 // we iterate over each contiguous chunk, writing each one in succession. 60 while (SrcReader.bytesRemaining() > 0) { 61 ArrayRef<uint8_t> Chunk; 62 if (auto EC = SrcReader.readLongestContiguousChunk(Chunk)) 63 return EC; 64 if (auto EC = writeBytes(Chunk)) 65 return EC; 66 } 67 return Error::success(); 68 } 69 70 std::pair<BinaryStreamWriter, BinaryStreamWriter> 71 BinaryStreamWriter::split(uint32_t Off) const { 72 assert(getLength() >= Off); 73 74 WritableBinaryStreamRef First = Stream.drop_front(Offset); 75 76 WritableBinaryStreamRef Second = First.drop_front(Off); 77 First = First.keep_front(Off); 78 BinaryStreamWriter W1{First}; 79 BinaryStreamWriter W2{Second}; 80 return std::make_pair(W1, W2); 81 } 82 83 Error BinaryStreamWriter::padToAlignment(uint32_t Align) { 84 uint32_t NewOffset = alignTo(Offset, Align); 85 if (NewOffset > getLength()) 86 return make_error<BinaryStreamError>(stream_error_code::stream_too_short); 87 while (Offset < NewOffset) 88 if (auto EC = writeInteger('\0')) 89 return EC; 90 return Error::success(); 91 } 92