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//===- BinaryStreamReader.cpp - Reads objects from a binary stream --------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "llvm/Support/BinaryStreamReader.h"
#include "llvm/Support/BinaryStreamError.h"
#include "llvm/Support/BinaryStreamRef.h"
#include "llvm/Support/LEB128.h"
using namespace llvm;
using endianness = llvm::support::endianness;
BinaryStreamReader::BinaryStreamReader(BinaryStreamRef Ref) : Stream(Ref) {}
BinaryStreamReader::BinaryStreamReader(BinaryStream &Stream) : Stream(Stream) {}
BinaryStreamReader::BinaryStreamReader(ArrayRef<uint8_t> Data,
endianness Endian)
: Stream(Data, Endian) {}
BinaryStreamReader::BinaryStreamReader(StringRef Data, endianness Endian)
: Stream(Data, Endian) {}
Error BinaryStreamReader::readLongestContiguousChunk(
ArrayRef<uint8_t> &Buffer) {
if (auto EC = Stream.readLongestContiguousChunk(Offset, Buffer))
return EC;
Offset += Buffer.size();
return Error::success();
}
Error BinaryStreamReader::readBytes(ArrayRef<uint8_t> &Buffer, uint32_t Size) {
if (auto EC = Stream.readBytes(Offset, Size, Buffer))
return EC;
Offset += Size;
return Error::success();
}
Error BinaryStreamReader::readULEB128(uint64_t &Dest) {
SmallVector<uint8_t, 10> EncodedBytes;
ArrayRef<uint8_t> NextByte;
// Copy the encoded ULEB into the buffer.
do {
if (auto Err = readBytes(NextByte, 1))
return Err;
EncodedBytes.push_back(NextByte[0]);
} while (NextByte[0] & 0x80);
Dest = decodeULEB128(EncodedBytes.begin(), nullptr, EncodedBytes.end());
return Error::success();
}
Error BinaryStreamReader::readSLEB128(int64_t &Dest) {
SmallVector<uint8_t, 10> EncodedBytes;
ArrayRef<uint8_t> NextByte;
// Copy the encoded ULEB into the buffer.
do {
if (auto Err = readBytes(NextByte, 1))
return Err;
EncodedBytes.push_back(NextByte[0]);
} while (NextByte[0] & 0x80);
Dest = decodeSLEB128(EncodedBytes.begin(), nullptr, EncodedBytes.end());
return Error::success();
}
Error BinaryStreamReader::readCString(StringRef &Dest) {
uint64_t OriginalOffset = getOffset();
uint64_t FoundOffset = 0;
while (true) {
uint64_t ThisOffset = getOffset();
ArrayRef<uint8_t> Buffer;
if (auto EC = readLongestContiguousChunk(Buffer))
return EC;
StringRef S(reinterpret_cast<const char *>(Buffer.begin()), Buffer.size());
size_t Pos = S.find_first_of('\0');
if (LLVM_LIKELY(Pos != StringRef::npos)) {
FoundOffset = Pos + ThisOffset;
break;
}
}
assert(FoundOffset >= OriginalOffset);
setOffset(OriginalOffset);
size_t Length = FoundOffset - OriginalOffset;
if (auto EC = readFixedString(Dest, Length))
return EC;
// Now set the offset back to after the null terminator.
setOffset(FoundOffset + 1);
return Error::success();
}
Error BinaryStreamReader::readWideString(ArrayRef<UTF16> &Dest) {
uint64_t Length = 0;
uint64_t OriginalOffset = getOffset();
const UTF16 *C;
while (true) {
if (auto EC = readObject(C))
return EC;
if (*C == 0x0000)
break;
++Length;
}
uint64_t NewOffset = getOffset();
setOffset(OriginalOffset);
if (auto EC = readArray(Dest, Length))
return EC;
setOffset(NewOffset);
return Error::success();
}
Error BinaryStreamReader::readFixedString(StringRef &Dest, uint32_t Length) {
ArrayRef<uint8_t> Bytes;
if (auto EC = readBytes(Bytes, Length))
return EC;
Dest = StringRef(reinterpret_cast<const char *>(Bytes.begin()), Bytes.size());
return Error::success();
}
Error BinaryStreamReader::readStreamRef(BinaryStreamRef &Ref) {
return readStreamRef(Ref, bytesRemaining());
}
Error BinaryStreamReader::readStreamRef(BinaryStreamRef &Ref, uint32_t Length) {
if (bytesRemaining() < Length)
return make_error<BinaryStreamError>(stream_error_code::stream_too_short);
Ref = Stream.slice(Offset, Length);
Offset += Length;
return Error::success();
}
Error BinaryStreamReader::readSubstream(BinarySubstreamRef &Ref,
uint32_t Length) {
Ref.Offset = getOffset();
return readStreamRef(Ref.StreamData, Length);
}
Error BinaryStreamReader::skip(uint64_t Amount) {
if (Amount > bytesRemaining())
return make_error<BinaryStreamError>(stream_error_code::stream_too_short);
Offset += Amount;
return Error::success();
}
Error BinaryStreamReader::padToAlignment(uint32_t Align) {
uint32_t NewOffset = alignTo(Offset, Align);
return skip(NewOffset - Offset);
}
uint8_t BinaryStreamReader::peek() const {
ArrayRef<uint8_t> Buffer;
auto EC = Stream.readBytes(Offset, 1, Buffer);
assert(!EC && "Cannot peek an empty buffer!");
llvm::consumeError(std::move(EC));
return Buffer[0];
}
std::pair<BinaryStreamReader, BinaryStreamReader>
BinaryStreamReader::split(uint64_t Off) const {
assert(getLength() >= Off);
BinaryStreamRef First = Stream.drop_front(Offset);
BinaryStreamRef Second = First.drop_front(Off);
First = First.keep_front(Off);
BinaryStreamReader W1{First};
BinaryStreamReader W2{Second};
return std::make_pair(W1, W2);
}
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