1 //===- BinaryStreamReader.cpp - Reads objects from a binary stream --------===// 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/BinaryStreamReader.h" 11 12 #include "llvm/Support/BinaryStreamError.h" 13 #include "llvm/Support/BinaryStreamRef.h" 14 15 using namespace llvm; 16 using endianness = llvm::support::endianness; 17 18 BinaryStreamReader::BinaryStreamReader(BinaryStreamRef Ref) : Stream(Ref) {} 19 20 BinaryStreamReader::BinaryStreamReader(BinaryStream &Stream) : Stream(Stream) {} 21 22 BinaryStreamReader::BinaryStreamReader(ArrayRef<uint8_t> Data, 23 endianness Endian) 24 : Stream(Data, Endian) {} 25 26 BinaryStreamReader::BinaryStreamReader(StringRef Data, endianness Endian) 27 : Stream(Data, Endian) {} 28 29 Error BinaryStreamReader::readLongestContiguousChunk( 30 ArrayRef<uint8_t> &Buffer) { 31 if (auto EC = Stream.readLongestContiguousChunk(Offset, Buffer)) 32 return EC; 33 Offset += Buffer.size(); 34 return Error::success(); 35 } 36 37 Error BinaryStreamReader::readBytes(ArrayRef<uint8_t> &Buffer, uint32_t Size) { 38 if (auto EC = Stream.readBytes(Offset, Size, Buffer)) 39 return EC; 40 Offset += Size; 41 return Error::success(); 42 } 43 44 Error BinaryStreamReader::readCString(StringRef &Dest) { 45 uint32_t OriginalOffset = getOffset(); 46 uint32_t FoundOffset = 0; 47 while (true) { 48 uint32_t ThisOffset = getOffset(); 49 ArrayRef<uint8_t> Buffer; 50 if (auto EC = readLongestContiguousChunk(Buffer)) 51 return EC; 52 StringRef S(reinterpret_cast<const char *>(Buffer.begin()), Buffer.size()); 53 size_t Pos = S.find_first_of('\0'); 54 if (LLVM_LIKELY(Pos != StringRef::npos)) { 55 FoundOffset = Pos + ThisOffset; 56 break; 57 } 58 } 59 assert(FoundOffset >= OriginalOffset); 60 61 setOffset(OriginalOffset); 62 size_t Length = FoundOffset - OriginalOffset; 63 64 if (auto EC = readFixedString(Dest, Length)) 65 return EC; 66 67 // Now set the offset back to after the null terminator. 68 setOffset(FoundOffset + 1); 69 return Error::success(); 70 } 71 72 Error BinaryStreamReader::readWideString(ArrayRef<UTF16> &Dest) { 73 uint32_t Length = 0; 74 uint32_t OriginalOffset = getOffset(); 75 const UTF16 *C; 76 while (true) { 77 if (auto EC = readObject(C)) 78 return EC; 79 if (*C == 0x0000) 80 break; 81 ++Length; 82 } 83 uint32_t NewOffset = getOffset(); 84 setOffset(OriginalOffset); 85 86 if (auto EC = readArray(Dest, Length)) 87 return EC; 88 setOffset(NewOffset); 89 return Error::success(); 90 } 91 92 Error BinaryStreamReader::readFixedString(StringRef &Dest, uint32_t Length) { 93 ArrayRef<uint8_t> Bytes; 94 if (auto EC = readBytes(Bytes, Length)) 95 return EC; 96 Dest = StringRef(reinterpret_cast<const char *>(Bytes.begin()), Bytes.size()); 97 return Error::success(); 98 } 99 100 Error BinaryStreamReader::readStreamRef(BinaryStreamRef &Ref) { 101 return readStreamRef(Ref, bytesRemaining()); 102 } 103 104 Error BinaryStreamReader::readStreamRef(BinaryStreamRef &Ref, uint32_t Length) { 105 if (bytesRemaining() < Length) 106 return make_error<BinaryStreamError>(stream_error_code::stream_too_short); 107 Ref = Stream.slice(Offset, Length); 108 Offset += Length; 109 return Error::success(); 110 } 111 112 Error BinaryStreamReader::skip(uint32_t Amount) { 113 if (Amount > bytesRemaining()) 114 return make_error<BinaryStreamError>(stream_error_code::stream_too_short); 115 Offset += Amount; 116 return Error::success(); 117 } 118 119 Error BinaryStreamReader::padToAlignment(uint32_t Align) { 120 uint32_t NewOffset = alignTo(Offset, Align); 121 return skip(NewOffset - Offset); 122 } 123 124 uint8_t BinaryStreamReader::peek() const { 125 ArrayRef<uint8_t> Buffer; 126 auto EC = Stream.readBytes(Offset, 1, Buffer); 127 assert(!EC && "Cannot peek an empty buffer!"); 128 llvm::consumeError(std::move(EC)); 129 return Buffer[0]; 130 } 131 132 std::pair<BinaryStreamReader, BinaryStreamReader> 133 BinaryStreamReader::split(uint32_t Off) const { 134 assert(getLength() >= Off); 135 136 BinaryStreamRef First = Stream.drop_front(Offset); 137 138 BinaryStreamRef Second = First.drop_front(Off); 139 First = First.keep_front(Off); 140 BinaryStreamReader W1{First}; 141 BinaryStreamReader W2{Second}; 142 return std::make_pair(W1, W2); 143 }