1 //===- BinaryStreamReader.cpp - Reads objects from a binary stream --------===// 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-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #include "llvm/Support/BinaryStreamReader.h" 10 11 #include "llvm/Support/BinaryStreamError.h" 12 #include "llvm/Support/BinaryStreamRef.h" 13 14 using namespace llvm; 15 using endianness = llvm::support::endianness; 16 17 BinaryStreamReader::BinaryStreamReader(BinaryStreamRef Ref) : Stream(Ref) {} 18 19 BinaryStreamReader::BinaryStreamReader(BinaryStream &Stream) : Stream(Stream) {} 20 21 BinaryStreamReader::BinaryStreamReader(ArrayRef<uint8_t> Data, 22 endianness Endian) 23 : Stream(Data, Endian) {} 24 25 BinaryStreamReader::BinaryStreamReader(StringRef Data, endianness Endian) 26 : Stream(Data, Endian) {} 27 28 Error BinaryStreamReader::readLongestContiguousChunk( 29 ArrayRef<uint8_t> &Buffer) { 30 if (auto EC = Stream.readLongestContiguousChunk(Offset, Buffer)) 31 return EC; 32 Offset += Buffer.size(); 33 return Error::success(); 34 } 35 36 Error BinaryStreamReader::readBytes(ArrayRef<uint8_t> &Buffer, uint32_t Size) { 37 if (auto EC = Stream.readBytes(Offset, Size, Buffer)) 38 return EC; 39 Offset += Size; 40 return Error::success(); 41 } 42 43 Error BinaryStreamReader::readCString(StringRef &Dest) { 44 uint32_t OriginalOffset = getOffset(); 45 uint32_t FoundOffset = 0; 46 while (true) { 47 uint32_t ThisOffset = getOffset(); 48 ArrayRef<uint8_t> Buffer; 49 if (auto EC = readLongestContiguousChunk(Buffer)) 50 return EC; 51 StringRef S(reinterpret_cast<const char *>(Buffer.begin()), Buffer.size()); 52 size_t Pos = S.find_first_of('\0'); 53 if (LLVM_LIKELY(Pos != StringRef::npos)) { 54 FoundOffset = Pos + ThisOffset; 55 break; 56 } 57 } 58 assert(FoundOffset >= OriginalOffset); 59 60 setOffset(OriginalOffset); 61 size_t Length = FoundOffset - OriginalOffset; 62 63 if (auto EC = readFixedString(Dest, Length)) 64 return EC; 65 66 // Now set the offset back to after the null terminator. 67 setOffset(FoundOffset + 1); 68 return Error::success(); 69 } 70 71 Error BinaryStreamReader::readWideString(ArrayRef<UTF16> &Dest) { 72 uint32_t Length = 0; 73 uint32_t OriginalOffset = getOffset(); 74 const UTF16 *C; 75 while (true) { 76 if (auto EC = readObject(C)) 77 return EC; 78 if (*C == 0x0000) 79 break; 80 ++Length; 81 } 82 uint32_t NewOffset = getOffset(); 83 setOffset(OriginalOffset); 84 85 if (auto EC = readArray(Dest, Length)) 86 return EC; 87 setOffset(NewOffset); 88 return Error::success(); 89 } 90 91 Error BinaryStreamReader::readFixedString(StringRef &Dest, uint32_t Length) { 92 ArrayRef<uint8_t> Bytes; 93 if (auto EC = readBytes(Bytes, Length)) 94 return EC; 95 Dest = StringRef(reinterpret_cast<const char *>(Bytes.begin()), Bytes.size()); 96 return Error::success(); 97 } 98 99 Error BinaryStreamReader::readStreamRef(BinaryStreamRef &Ref) { 100 return readStreamRef(Ref, bytesRemaining()); 101 } 102 103 Error BinaryStreamReader::readStreamRef(BinaryStreamRef &Ref, uint32_t Length) { 104 if (bytesRemaining() < Length) 105 return make_error<BinaryStreamError>(stream_error_code::stream_too_short); 106 Ref = Stream.slice(Offset, Length); 107 Offset += Length; 108 return Error::success(); 109 } 110 111 Error BinaryStreamReader::readSubstream(BinarySubstreamRef &Stream, 112 uint32_t Size) { 113 Stream.Offset = getOffset(); 114 return readStreamRef(Stream.StreamData, Size); 115 } 116 117 Error BinaryStreamReader::skip(uint32_t Amount) { 118 if (Amount > bytesRemaining()) 119 return make_error<BinaryStreamError>(stream_error_code::stream_too_short); 120 Offset += Amount; 121 return Error::success(); 122 } 123 124 Error BinaryStreamReader::padToAlignment(uint32_t Align) { 125 uint32_t NewOffset = alignTo(Offset, Align); 126 return skip(NewOffset - Offset); 127 } 128 129 uint8_t BinaryStreamReader::peek() const { 130 ArrayRef<uint8_t> Buffer; 131 auto EC = Stream.readBytes(Offset, 1, Buffer); 132 assert(!EC && "Cannot peek an empty buffer!"); 133 llvm::consumeError(std::move(EC)); 134 return Buffer[0]; 135 } 136 137 std::pair<BinaryStreamReader, BinaryStreamReader> 138 BinaryStreamReader::split(uint32_t Off) const { 139 assert(getLength() >= Off); 140 141 BinaryStreamRef First = Stream.drop_front(Offset); 142 143 BinaryStreamRef Second = First.drop_front(Off); 144 First = First.keep_front(Off); 145 BinaryStreamReader W1{First}; 146 BinaryStreamReader W2{Second}; 147 return std::make_pair(W1, W2); 148 }