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/*
* Copyright (C) 2017 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef ART_RUNTIME_DEX_INSTRUCTION_ITERATOR_H_
#define ART_RUNTIME_DEX_INSTRUCTION_ITERATOR_H_
#include <iterator>
#include "dex_instruction.h"
#include "base/logging.h"
namespace art {
// Base helper class to prevent duplicated comparators.
class DexInstructionIteratorBase : public std::iterator<std::forward_iterator_tag, Instruction> {
public:
using value_type = std::iterator<std::forward_iterator_tag, Instruction>::value_type;
using difference_type = std::iterator<std::forward_iterator_tag, value_type>::difference_type;
DexInstructionIteratorBase() = default;
explicit DexInstructionIteratorBase(const value_type* inst) : inst_(inst) {}
const value_type* Inst() const {
return inst_;
}
// Return the dex pc for an iterator compared to the code item begin.
uint32_t GetDexPC(const DexInstructionIteratorBase& code_item_begin) {
return reinterpret_cast<const uint16_t*>(inst_) -
reinterpret_cast<const uint16_t*>(code_item_begin.inst_);
}
protected:
const value_type* inst_ = nullptr;
};
static ALWAYS_INLINE inline bool operator==(const DexInstructionIteratorBase& lhs,
const DexInstructionIteratorBase& rhs) {
return lhs.Inst() == rhs.Inst();
}
static inline bool operator!=(const DexInstructionIteratorBase& lhs,
const DexInstructionIteratorBase& rhs) {
return !(lhs == rhs);
}
static inline bool operator<(const DexInstructionIteratorBase& lhs,
const DexInstructionIteratorBase& rhs) {
return lhs.Inst() < rhs.Inst();
}
static inline bool operator>(const DexInstructionIteratorBase& lhs,
const DexInstructionIteratorBase& rhs) {
return rhs < lhs;
}
static inline bool operator<=(const DexInstructionIteratorBase& lhs,
const DexInstructionIteratorBase& rhs) {
return !(rhs < lhs);
}
static inline bool operator>=(const DexInstructionIteratorBase& lhs,
const DexInstructionIteratorBase& rhs) {
return !(lhs < rhs);
}
class DexInstructionIterator : public DexInstructionIteratorBase {
public:
using value_type = std::iterator<std::forward_iterator_tag, Instruction>::value_type;
using difference_type = std::iterator<std::forward_iterator_tag, value_type>::difference_type;
using DexInstructionIteratorBase::DexInstructionIteratorBase;
explicit DexInstructionIterator(const uint16_t* inst)
: DexInstructionIteratorBase(value_type::At(inst)) {}
// Value after modification.
DexInstructionIterator& operator++() {
inst_ = inst_->Next();
return *this;
}
// Value before modification.
DexInstructionIterator operator++(int) {
DexInstructionIterator temp = *this;
++*this;
return temp;
}
const value_type& operator*() const {
return *inst_;
}
const value_type* operator->() const {
return &**this;
}
};
class SafeDexInstructionIterator : public DexInstructionIteratorBase {
public:
explicit SafeDexInstructionIterator(const DexInstructionIteratorBase& start,
const DexInstructionIteratorBase& end)
: DexInstructionIteratorBase(start.Inst())
, end_(end.Inst()) {}
// Value after modification, does not read past the end of the allowed region. May increment past
// the end of the code item though.
SafeDexInstructionIterator& operator++() {
AssertValid();
const size_t size_code_units = Inst()->CodeUnitsRequiredForSizeComputation();
const size_t available = reinterpret_cast<const uint16_t*>(end_) -
reinterpret_cast<const uint16_t*>(Inst());
if (UNLIKELY(size_code_units > available)) {
error_state_ = true;
return *this;
}
const size_t instruction_size = inst_->SizeInCodeUnits();
if (UNLIKELY(instruction_size > available)) {
error_state_ = true;
return *this;
}
inst_ = inst_->RelativeAt(instruction_size);
return *this;
}
// Value before modification.
SafeDexInstructionIterator operator++(int) {
SafeDexInstructionIterator temp = *this;
++*this;
return temp;
}
const value_type& operator*() const {
AssertValid();
return *inst_;
}
const value_type* operator->() const {
AssertValid();
return &**this;
}
// Returns true if the iterator is in an error state. This occurs when an instruction couldn't
// have its size computed without reading past the end iterator.
bool IsErrorState() const {
return error_state_;
}
private:
ALWAYS_INLINE void AssertValid() const {
DCHECK(!IsErrorState());
DCHECK_LT(Inst(), end_);
}
const value_type* end_ = nullptr;
bool error_state_ = false;
};
} // namespace art
#endif // ART_RUNTIME_DEX_INSTRUCTION_ITERATOR_H_
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