llvm-project/llvm/lib/DebugInfo/MSF/StreamReader.cpp

94 lines
2.7 KiB
C++

//===- StreamReader.cpp - Reads bytes and objects from a stream -----------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "llvm/DebugInfo/MSF/StreamReader.h"
#include "llvm/DebugInfo/MSF/MSFError.h"
#include "llvm/DebugInfo/MSF/StreamRef.h"
using namespace llvm;
using namespace llvm::msf;
StreamReader::StreamReader(ReadableStreamRef S) : Stream(S), Offset(0) {}
Error StreamReader::readLongestContiguousChunk(ArrayRef<uint8_t> &Buffer) {
if (auto EC = Stream.readLongestContiguousChunk(Offset, Buffer))
return EC;
Offset += Buffer.size();
return Error::success();
}
Error StreamReader::readBytes(ArrayRef<uint8_t> &Buffer, uint32_t Size) {
if (auto EC = Stream.readBytes(Offset, Size, Buffer))
return EC;
Offset += Size;
return Error::success();
}
Error StreamReader::readInteger(uint16_t &Dest) {
const support::ulittle16_t *P;
if (auto EC = readObject(P))
return EC;
Dest = *P;
return Error::success();
}
Error StreamReader::readInteger(uint32_t &Dest) {
const support::ulittle32_t *P;
if (auto EC = readObject(P))
return EC;
Dest = *P;
return Error::success();
}
Error StreamReader::readZeroString(StringRef &Dest) {
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;
do {
if (auto EC = readObject(C))
return EC;
if (*C != '\0')
++Length;
} while (*C != '\0');
// Now go back and request a reference for that many bytes.
uint32_t NewOffset = getOffset();
setOffset(OriginalOffset);
ArrayRef<uint8_t> Data;
if (auto EC = readBytes(Data, Length))
return EC;
Dest = StringRef(reinterpret_cast<const char *>(Data.begin()), Data.size());
// Now set the offset back to where it was after we calculated the length.
setOffset(NewOffset);
return Error::success();
}
Error StreamReader::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 StreamReader::readStreamRef(ReadableStreamRef &Ref) {
return readStreamRef(Ref, bytesRemaining());
}
Error StreamReader::readStreamRef(ReadableStreamRef &Ref, uint32_t Length) {
if (bytesRemaining() < Length)
return make_error<MSFError>(msf_error_code::insufficient_buffer);
Ref = Stream.slice(Offset, Length);
Offset += Length;
return Error::success();
}