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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/ErrorHandling.h"
#include "llvm/Support/Host.h"
#include "llvm/Support/SwapByteOrder.h"
#include "llvm/Support/LEB128.h"
using namespace llvm;
template <typename T>
static T getU(uint32_t *offset_ptr, const DataExtractor *de,
bool isLittleEndian, const char *Data) {
T val = 0;
uint32_t offset = *offset_ptr;
if (de->isValidOffsetForDataOfSize(offset, sizeof(val))) {
std::memcpy(&val, &Data[offset], sizeof(val));
if (sys::IsLittleEndianHost != isLittleEndian)
sys::swapByteOrder(val);
// Advance the offset
*offset_ptr += sizeof(val);
}
return val;
}
template <typename T>
static T *getUs(uint32_t *offset_ptr, T *dst, uint32_t count,
const DataExtractor *de, bool isLittleEndian, const char *Data){
uint32_t offset = *offset_ptr;
if (count > 0 && de->isValidOffsetForDataOfSize(offset, sizeof(*dst)*count)) {
for (T *value_ptr = dst, *end = dst + count; value_ptr != end;
++value_ptr, offset += sizeof(*dst))
*value_ptr = getU<T>(offset_ptr, de, isLittleEndian, Data);
// Advance the offset
*offset_ptr = offset;
// Return a non-NULL pointer to the converted data as an indicator of
// success
return dst;
}
return nullptr;
}
uint8_t DataExtractor::getU8(uint32_t *offset_ptr) const {
return getU<uint8_t>(offset_ptr, this, IsLittleEndian, Data.data());
}
uint8_t *
DataExtractor::getU8(uint32_t *offset_ptr, uint8_t *dst, uint32_t count) const {
return getUs<uint8_t>(offset_ptr, dst, count, this, IsLittleEndian,
Data.data());
}
uint16_t DataExtractor::getU16(uint32_t *offset_ptr) const {
return getU<uint16_t>(offset_ptr, this, IsLittleEndian, Data.data());
}
uint16_t *DataExtractor::getU16(uint32_t *offset_ptr, uint16_t *dst,
uint32_t count) const {
return getUs<uint16_t>(offset_ptr, dst, count, this, IsLittleEndian,
Data.data());
}
uint32_t DataExtractor::getU24(uint32_t *offset_ptr) const {
uint24_t ExtractedVal =
getU<uint24_t>(offset_ptr, this, IsLittleEndian, Data.data());
// The 3 bytes are in the correct byte order for the host.
return ExtractedVal.getAsUint32(sys::IsLittleEndianHost);
}
uint32_t DataExtractor::getU32(uint32_t *offset_ptr) const {
return getU<uint32_t>(offset_ptr, this, IsLittleEndian, Data.data());
}
uint32_t *DataExtractor::getU32(uint32_t *offset_ptr, uint32_t *dst,
uint32_t count) const {
return getUs<uint32_t>(offset_ptr, dst, count, this, IsLittleEndian,
Data.data());
}
uint64_t DataExtractor::getU64(uint32_t *offset_ptr) const {
return getU<uint64_t>(offset_ptr, this, IsLittleEndian, Data.data());
}
uint64_t *DataExtractor::getU64(uint32_t *offset_ptr, uint64_t *dst,
uint32_t count) const {
return getUs<uint64_t>(offset_ptr, dst, count, this, IsLittleEndian,
Data.data());
}
uint64_t
DataExtractor::getUnsigned(uint32_t *offset_ptr, uint32_t byte_size) const {
switch (byte_size) {
case 1:
return getU8(offset_ptr);
case 2:
return getU16(offset_ptr);
case 4:
return getU32(offset_ptr);
case 8:
return getU64(offset_ptr);
}
llvm_unreachable("getUnsigned unhandled case!");
}
int64_t
DataExtractor::getSigned(uint32_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!");
}
const char *DataExtractor::getCStr(uint32_t *offset_ptr) const {
uint32_t offset = *offset_ptr;
StringRef::size_type pos = Data.find('\0', offset);
if (pos != StringRef::npos) {
*offset_ptr = pos + 1;
return Data.data() + offset;
}
return nullptr;
}
StringRef DataExtractor::getCStrRef(uint32_t *OffsetPtr) const {
uint32_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);
}
return StringRef();
}
uint64_t DataExtractor::getULEB128(uint32_t *offset_ptr) const {
assert(*offset_ptr <= Data.size());
const char *error;
unsigned bytes_read;
uint64_t result = decodeULEB128(
reinterpret_cast<const uint8_t *>(Data.data() + *offset_ptr), &bytes_read,
reinterpret_cast<const uint8_t *>(Data.data() + Data.size()), &error);
if (error)
return 0;
*offset_ptr += bytes_read;
return result;
}
int64_t DataExtractor::getSLEB128(uint32_t *offset_ptr) const {
assert(*offset_ptr <= Data.size());
const char *error;
unsigned bytes_read;
int64_t result = decodeSLEB128(
reinterpret_cast<const uint8_t *>(Data.data() + *offset_ptr), &bytes_read,
reinterpret_cast<const uint8_t *>(Data.data() + Data.size()), &error);
if (error)
return 0;
*offset_ptr += bytes_read;
return result;
}
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