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//===-- DataExtractor.cpp -------------------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "llvm/Support/DataExtractor.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/Host.h"
#include "llvm/Support/SwapByteOrder.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)
val = 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 NULL;
}
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::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 NULL;
}
uint64_t DataExtractor::getULEB128(uint32_t *offset_ptr) const {
uint64_t result = 0;
if (Data.empty())
return 0;
unsigned shift = 0;
uint32_t offset = *offset_ptr;
uint8_t byte = 0;
while (isValidOffset(offset)) {
byte = Data[offset++];
result |= uint64_t(byte & 0x7f) << shift;
shift += 7;
if ((byte & 0x80) == 0)
break;
}
*offset_ptr = offset;
return result;
}
int64_t DataExtractor::getSLEB128(uint32_t *offset_ptr) const {
int64_t result = 0;
if (Data.empty())
return 0;
unsigned shift = 0;
uint32_t offset = *offset_ptr;
uint8_t byte = 0;
while (isValidOffset(offset)) {
byte = Data[offset++];
result |= uint64_t(byte & 0x7f) << shift;
shift += 7;
if ((byte & 0x80) == 0)
break;
}
// Sign bit of byte is 2nd high order bit (0x40)
if (shift < 64 && (byte & 0x40))
result |= -(1ULL << shift);
*offset_ptr = offset;
return result;
}
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