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//===-- DataExtractor.cpp -------------------------------------------------===//
//
// 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/DataExtractor.h"
#include "llvm/Support/Errc.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/Host.h"
#include "llvm/Support/LEB128.h"
#include "llvm/Support/SwapByteOrder.h"
using namespace llvm;
bool DataExtractor::prepareRead(uint64_t Offset, uint64_t Size,
Error *E) const {
if (isValidOffsetForDataOfSize(Offset, Size))
return true;
if (E) {
if (Offset <= Data.size())
*E = createStringError(
errc::illegal_byte_sequence,
"unexpected end of data at offset 0x%zx while reading [0x%" PRIx64
", 0x%" PRIx64 ")",
Data.size(), Offset, Offset + Size);
else
*E = createStringError(errc::invalid_argument,
"offset 0x%" PRIx64
" is beyond the end of data at 0x%zx",
Offset, Data.size());
}
return false;
}
static bool isError(Error *E) { return E && *E; }
template <typename T>
T DataExtractor::getU(uint64_t *offset_ptr, Error *Err) const {
ErrorAsOutParameter ErrAsOut(Err);
T val = 0;
if (isError(Err))
return val;
uint64_t offset = *offset_ptr;
if (!prepareRead(offset, sizeof(T), Err))
return val;
std::memcpy(&val, &Data.data()[offset], sizeof(val));
if (sys::IsLittleEndianHost != IsLittleEndian)
sys::swapByteOrder(val);
// Advance the offset
*offset_ptr += sizeof(val);
return val;
}
template <typename T>
T *DataExtractor::getUs(uint64_t *offset_ptr, T *dst, uint32_t count,
Error *Err) const {
ErrorAsOutParameter ErrAsOut(Err);
if (isError(Err))
return nullptr;
uint64_t offset = *offset_ptr;
if (!prepareRead(offset, sizeof(*dst) * count, Err))
return nullptr;
for (T *value_ptr = dst, *end = dst + count; value_ptr != end;
++value_ptr, offset += sizeof(*dst))
*value_ptr = getU<T>(offset_ptr, Err);
// Advance the offset
*offset_ptr = offset;
// Return a non-NULL pointer to the converted data as an indicator of
// success
return dst;
}
uint8_t DataExtractor::getU8(uint64_t *offset_ptr, llvm::Error *Err) const {
return getU<uint8_t>(offset_ptr, Err);
}
uint8_t *DataExtractor::getU8(uint64_t *offset_ptr, uint8_t *dst,
uint32_t count) const {
return getUs<uint8_t>(offset_ptr, dst, count, nullptr);
}
uint8_t *DataExtractor::getU8(Cursor &C, uint8_t *Dst, uint32_t Count) const {
return getUs<uint8_t>(&C.Offset, Dst, Count, &C.Err);
}
uint16_t DataExtractor::getU16(uint64_t *offset_ptr, llvm::Error *Err) const {
return getU<uint16_t>(offset_ptr, Err);
}
uint16_t *DataExtractor::getU16(uint64_t *offset_ptr, uint16_t *dst,
uint32_t count) const {
return getUs<uint16_t>(offset_ptr, dst, count, nullptr);
}
uint32_t DataExtractor::getU24(uint64_t *OffsetPtr, Error *Err) const {
uint24_t ExtractedVal = getU<uint24_t>(OffsetPtr, Err);
// The 3 bytes are in the correct byte order for the host.
return ExtractedVal.getAsUint32(sys::IsLittleEndianHost);
}
uint32_t DataExtractor::getU32(uint64_t *offset_ptr, llvm::Error *Err) const {
return getU<uint32_t>(offset_ptr, Err);
}
uint32_t *DataExtractor::getU32(uint64_t *offset_ptr, uint32_t *dst,
uint32_t count) const {
return getUs<uint32_t>(offset_ptr, dst, count, nullptr);
}
uint64_t DataExtractor::getU64(uint64_t *offset_ptr, llvm::Error *Err) const {
return getU<uint64_t>(offset_ptr, Err);
}
uint64_t *DataExtractor::getU64(uint64_t *offset_ptr, uint64_t *dst,
uint32_t count) const {
return getUs<uint64_t>(offset_ptr, dst, count, nullptr);
}
uint64_t DataExtractor::getUnsigned(uint64_t *offset_ptr, uint32_t byte_size,
llvm::Error *Err) const {
switch (byte_size) {
case 1:
return getU8(offset_ptr, Err);
case 2:
return getU16(offset_ptr, Err);
case 4:
return getU32(offset_ptr, Err);
case 8:
return getU64(offset_ptr, Err);
}
llvm_unreachable("getUnsigned unhandled case!");
}
int64_t
DataExtractor::getSigned(uint64_t *offset_ptr, uint32_t byte_size) const {
switch (byte_size) {
case 1:
return (int8_t)getU8(offset_ptr);
case 2:
return (int16_t)getU16(offset_ptr);
case 4:
return (int32_t)getU32(offset_ptr);
case 8:
return (int64_t)getU64(offset_ptr);
}
llvm_unreachable("getSigned unhandled case!");
}
StringRef DataExtractor::getCStrRef(uint64_t *OffsetPtr, Error *Err) const {
ErrorAsOutParameter ErrAsOut(Err);
if (isError(Err))
return StringRef();
uint64_t Start = *OffsetPtr;
StringRef::size_type Pos = Data.find('\0', Start);
if (Pos != StringRef::npos) {
*OffsetPtr = Pos + 1;
return StringRef(Data.data() + Start, Pos - Start);
}
if (Err)
*Err = createStringError(errc::illegal_byte_sequence,
"no null terminated string at offset 0x%" PRIx64,
Start);
return StringRef();
}
StringRef DataExtractor::getFixedLengthString(uint64_t *OffsetPtr,
uint64_t Length,
StringRef TrimChars) const {
StringRef Bytes(getBytes(OffsetPtr, Length));
return Bytes.trim(TrimChars);
}
StringRef DataExtractor::getBytes(uint64_t *OffsetPtr, uint64_t Length,
Error *Err) const {
ErrorAsOutParameter ErrAsOut(Err);
if (isError(Err))
return StringRef();
if (!prepareRead(*OffsetPtr, Length, Err))
return StringRef();
StringRef Result = Data.substr(*OffsetPtr, Length);
*OffsetPtr += Length;
return Result;
}
template <typename T>
static T getLEB128(StringRef Data, uint64_t *OffsetPtr, Error *Err,
T (&Decoder)(const uint8_t *p, unsigned *n,
const uint8_t *end, const char **error)) {
ArrayRef<uint8_t> Bytes = arrayRefFromStringRef(Data);
assert(*OffsetPtr <= Bytes.size());
ErrorAsOutParameter ErrAsOut(Err);
if (isError(Err))
return T();
const char *error;
unsigned bytes_read;
T result =
Decoder(Bytes.data() + *OffsetPtr, &bytes_read, Bytes.end(), &error);
if (error) {
if (Err)
*Err = createStringError(errc::illegal_byte_sequence,
"unable to decode LEB128 at offset 0x%8.8" PRIx64
": %s",
*OffsetPtr, error);
return T();
}
*OffsetPtr += bytes_read;
return result;
}
uint64_t DataExtractor::getULEB128(uint64_t *offset_ptr, Error *Err) const {
return getLEB128(Data, offset_ptr, Err, decodeULEB128);
}
int64_t DataExtractor::getSLEB128(uint64_t *offset_ptr, Error *Err) const {
return getLEB128(Data, offset_ptr, Err, decodeSLEB128);
}
void DataExtractor::skip(Cursor &C, uint64_t Length) const {
ErrorAsOutParameter ErrAsOut(&C.Err);
if (isError(&C.Err))
return;
if (prepareRead(C.Offset, Length, &C.Err))
C.Offset += Length;
}
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