llvm/lib/Support/BinaryStreamReader.cpp
Daniel Jasper 5d9d83fb55 Revert r301986 (and subsequent r301987).
The patch is failing to add StringTableStreamBuilder.h, but that isn't
even discovered because the corresponding StringTableStreamBuilder.cpp
isn't added to any CMakeLists.txt file and thus never built. I think
this patch is just incomplete.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@302002 91177308-0d34-0410-b5e6-96231b3b80d8
2017-05-03 07:29:25 +00:00

96 lines
2.8 KiB
C++

//===- BinaryStreamReader.cpp - Reads objects from a binary stream --------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "llvm/Support/BinaryStreamReader.h"
#include "llvm/Support/BinaryStreamError.h"
#include "llvm/Support/BinaryStreamRef.h"
using namespace llvm;
BinaryStreamReader::BinaryStreamReader(BinaryStreamRef S)
: Stream(S), Offset(0) {}
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::readCString(StringRef &Dest) {
// TODO: This could be made more efficient by using readLongestContiguousChunk
// and searching for null terminators in the resulting buffer.
uint32_t Length = 0;
// First compute the length of the string by reading 1 byte at a time.
uint32_t OriginalOffset = getOffset();
const char *C;
while (true) {
if (auto EC = readObject(C))
return EC;
if (*C == '\0')
break;
++Length;
}
// Now go back and request a reference for that many bytes.
uint32_t NewOffset = getOffset();
setOffset(OriginalOffset);
if (auto EC = readFixedString(Dest, Length))
return EC;
// Now set the offset back to where it was after we calculated the length.
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::skip(uint32_t Amount) {
if (Amount > bytesRemaining())
return make_error<BinaryStreamError>(stream_error_code::stream_too_short);
Offset += Amount;
return Error::success();
}
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];
}