iterators.hpp

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/* Copyright 2017 - 2026 R. Thomas
 * Copyright 2017 - 2026 Quarkslab
 * Copyright 2017 - 2021, NVIDIA CORPORATION. All rights reserved.
 *
 * 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 LIEF_ITERATORS_H
#define LIEF_ITERATORS_H
#include <cmath>
#include <cstddef>
#include <cassert>
#include <iterator>
#include <functional>
#include <algorithm>
#include <type_traits>
#include <vector>
 
namespace LIEF {
 
template<class T>
using decay_t = typename std::decay<T>::type;
 
template<class T>
using add_const_t = typename std::add_const<T>::type;
 
template<class T>
using remove_const_t = typename std::remove_const<T>::type;
 
template< class T >
using add_lvalue_reference_t = typename std::add_lvalue_reference<T>::type;
 

template<class T, typename U = typename decay_t<T>::value_type,
         class ITERATOR_T = typename decay_t<T>::iterator>
class ref_iterator {
  public:
  using iterator_category = std::bidirectional_iterator_tag;
  using value_type = decay_t<U>;
  using difference_type = ptrdiff_t;
  using pointer = typename std::remove_pointer<U>::type*;
  using reference = typename std::remove_pointer<U>::type&;
 
  using container_type = T;          // e.g. std::vector<Section*>&
  using DT_VAL         = U;          // e.g. Section*
  using DT             = decay_t<T>; // e.g. std::vector<Section>
  using ref_t          = typename ref_iterator::reference;
  using pointer_t      = typename ref_iterator::pointer;
 
  ref_iterator(T container) :
    container_{std::forward<T>(container)}
  {
    it_ = std::begin(container_);
  }
 
  ref_iterator(const ref_iterator& copy) :
    container_{copy.container_},
    it_{std::begin(container_)},
    distance_{copy.distance_}
  {
    std::advance(it_, distance_);
  }
 
 
  ref_iterator& operator=(ref_iterator other) {
    swap(other);
    return *this;
  }
 
  void swap(ref_iterator& other) noexcept {
    std::swap(const_cast<add_lvalue_reference_t<remove_const_t<DT>>>(container_),
              const_cast<add_lvalue_reference_t<remove_const_t<DT>>>(other.container_));
    std::swap(it_, other.it_);
    std::swap(distance_, other.distance_);
  }
 
 
  ref_iterator& operator++() {
    it_ = std::next(it_);
    distance_++;
    return *this;
  }
 
  ref_iterator operator++(int) {
    ref_iterator retval = *this;
    ++(*this);
    return retval;
  }
 
  ref_iterator& operator--() {
    if (it_ != std::begin(container_)) {
      it_ = std::prev(it_);
      distance_--;
    }
    return *this;
  }
 
  ref_iterator operator--(int) {
    ref_iterator retval = *this;
    --(*this);
    return retval;
  }
 
 
  ref_iterator& operator+=(const typename ref_iterator::difference_type& movement) {
    std::advance(it_, movement);
    distance_ += movement;
    return *this;
  }
 
 
  ref_iterator& operator-=(const typename ref_iterator::difference_type& movement) {
    return (*this) += -movement;
  }
 
 
  typename std::enable_if<!std::is_const<ref_t>::value, remove_const_t<ref_t>>::type
  operator[](size_t n) {
    return const_cast<remove_const_t<ref_t>>(static_cast<const ref_iterator*>(this)->operator[](n));
  }
 
 
  add_const_t<ref_t> operator[](size_t n) const {
    assert(n < size() && "integrity error: out of bound");
 
    auto* no_const_this = const_cast<ref_iterator*>(this);
 
    typename ref_iterator::difference_type saved_dist = std::distance(std::begin(no_const_this->container_), no_const_this->it_);
    no_const_this->it_ = std::begin(no_const_this->container_);
    std::advance(no_const_this->it_, n);
 
    auto&& v = const_cast<add_const_t<ref_t>>(no_const_this->operator*());
 
    no_const_this->it_ = std::begin(no_const_this->container_);
    std::advance(no_const_this->it_, saved_dist);
 
    return v;
  }
 
  ref_iterator operator+(typename ref_iterator::difference_type n) const {
    ref_iterator tmp = *this;
    return tmp += n;
  }
 
 
  ref_iterator operator-(typename ref_iterator::difference_type n) const {
    ref_iterator tmp = *this;
    return tmp -= n;
  }
 
 
  typename ref_iterator::difference_type operator-(const ref_iterator& rhs) const {
    return distance_ - rhs.distance_;
  }
 
  bool operator<(const ref_iterator& rhs) const {
    return (rhs - *this) > 0;
  }
 
 
  bool operator>(const ref_iterator& rhs) const {
    return rhs < *this;
  }
 
 
  bool operator>=(const ref_iterator& rhs) const {
    return !(*this < rhs);
  }
 
 
  bool operator<=(const ref_iterator& rhs) const {
    return !(*this > rhs);
  }
 
  ref_iterator begin() const {
    return container_;
  }
 
  ref_iterator cbegin() const {
    return begin();
  }
 
  ref_iterator end()  const {
    ref_iterator it = ref_iterator{container_};
    it.it_ = std::end(it.container_);
    it.distance_ = it.size();
    return it;
  }
 
  ref_iterator cend() const {
    return end();
  }
 
  bool operator==(const ref_iterator& other) const {
    return (size() == other.size() && distance_ == other.distance_);
  }
 
  bool operator!=(const ref_iterator& other) const {
    return !(*this == other);
  }
 
  size_t size() const {
    return container_.size();
  }
 
  bool empty() const {
    return container_.empty();
  }
 
  typename std::enable_if<!std::is_const<ref_t>::value, remove_const_t<ref_t>>::type
  operator*() {
    return const_cast<remove_const_t<ref_t>>(static_cast<const ref_iterator*>(this)->operator*());
  }
 
  template<typename V = DT_VAL>
  typename std::enable_if<std::is_pointer<V>::value, add_const_t<ref_t>>::type
  operator*() const {
    assert(*it_ && "integrity error: nullptr");
    return const_cast<add_const_t<ref_t>>(static_cast<ref_t>(**it_));
  }
 
  template<typename V = DT_VAL>
  typename std::enable_if<!std::is_pointer<V>::value, add_const_t<ref_t>>::type
  operator*() const {
    return const_cast<add_const_t<ref_t>>(*(it_));
  }
 
 
  typename std::enable_if<!std::is_const<pointer_t>::value, pointer_t>::type
  operator->() {
    return const_cast<remove_const_t<pointer_t>>(static_cast<const ref_iterator*>(this)->operator->());
  }
 
  add_const_t<pointer_t> operator->() const {
    return const_cast<add_const_t<pointer_t>>(&(operator*()));
  }
 
  protected:
  T container_;
  ITERATOR_T it_;
  typename ref_iterator::difference_type distance_{};
};
 

template<class T, typename U = typename decay_t<T>::value_type, class CT = typename std::add_const<T>::type>
using const_ref_iterator = ref_iterator<CT, U, typename decay_t<CT>::const_iterator>;
 

template<class T, typename U = typename decay_t<T>::value_type,
         class ITERATOR_T = typename decay_t<T>::iterator>
class filter_iterator {
 
  public:
  using iterator_category = std::forward_iterator_tag;
  using value_type = decay_t<U>;
  using difference_type = ptrdiff_t;
  using pointer = typename std::remove_pointer<U>::type*;
  using reference = typename std::remove_pointer<U>::type&;
 
  using container_type = T;
  using DT_VAL         = U;
  using DT        = decay_t<T>;
  using ref_t     = typename filter_iterator::reference;
  using pointer_t = typename filter_iterator::pointer;
  using filter_t  = std::function<bool (const typename DT::value_type&)>;
 
  filter_iterator(T container, filter_t filter) :
    container_{std::forward<T>(container)},
    filters_{}
  {
 
    it_ = std::begin(container_);
 
    filters_.push_back(filter),
    it_ = std::begin(container_);
 
    if (it_ != std::end(container_)) {
      if (!std::all_of(std::begin(filters_), std::end(filters_), [this] (const filter_t& f) {return f(*it_);})) {
        next();
      }
    }
  }
 
  filter_iterator(T container, const std::vector<filter_t>& filters) :
    container_{std::forward<T>(container)},
    filters_{filters}
  {
 
    it_ = std::begin(container_);
 
    if (it_ != std::end(container_)) {
      if (!std::all_of(std::begin(filters_), std::end(filters_), [this] (const filter_t& f) {return f(*it_);})) {
        next();
      }
    }
  }
 
  filter_iterator(T container) :
    container_{std::forward<T>(container)},
    filters_{}
  {
    it_ = std::begin(container_);
  }
 
  filter_iterator(const filter_iterator& copy) :
    container_{copy.container_},
    it_{std::begin(container_)},
    filters_{copy.filters_},
    distance_{copy.distance_}
  {
    std::advance(it_, distance_);
  }
 
  filter_iterator& operator=(filter_iterator other) {
    swap(other);
    return *this;
  }
 
  void swap(filter_iterator& other) noexcept {
    std::swap(const_cast<remove_const_t<DT>&>(container_), const_cast<remove_const_t<DT>&>(other.container_));
    std::swap(it_,        other.it_);
    std::swap(filters_,   other.filters_);
    std::swap(size_c_,    other.size_c_);
    std::swap(distance_,  other.distance_);
  }
 
 
  filter_iterator& def(filter_t func) {
    filters_.push_back(func);
    size_c_ = 0;
    return *this;
  }
 
  filter_iterator& operator++() {
    next();
    return *this;
  }
 
  filter_iterator operator++(int) {
    filter_iterator retval = *this;
    ++(*this);
    return retval;
  }
 
  filter_iterator begin() const {
    return {container_, filters_};
  }
 
  filter_iterator cbegin() const {
    return begin();
  }
 
  filter_iterator end() const {
    // we don't need filter for the end iterator
    filter_iterator it_end{container_};
 
    it_end.it_       =  it_end.container_.end();
    it_end.distance_ = it_end.container_.size();
 
    return it_end;
  }
 
  filter_iterator cend() const {
    return end();
  }
 
  typename std::enable_if<!std::is_const<ref_t>::value, remove_const_t<ref_t>>::type
  operator*() {
    return const_cast<remove_const_t<ref_t>>(static_cast<const filter_iterator*>(this)->operator*());
  }
 
  template<typename V = DT_VAL>
  typename std::enable_if<std::is_pointer<V>::value, add_const_t<ref_t>>::type
  operator*() const {
    assert(*it_ && "integrity error: nullptr");
    return const_cast<add_const_t<ref_t>>(static_cast<ref_t>(**it_));
  }
 
  template<typename V = DT_VAL>
  typename std::enable_if<!std::is_pointer<V>::value, add_const_t<ref_t>>::type
  operator*() const {
    return const_cast<add_const_t<ref_t>>(*(it_));
  }
 
 
  typename std::enable_if<!std::is_const<ref_t>::value, remove_const_t<ref_t>>::type
  operator[](size_t n) {
    return const_cast<remove_const_t<ref_t>>(static_cast<const filter_iterator*>(this)->operator[](n));
  }
 
  add_const_t<ref_t> operator[](size_t n) const {
    assert(n < size() && "integrity error: out of bound");
 
    auto it = begin();
    std::advance(it, n);
    return const_cast<add_const_t<ref_t>>(*it);
  }
 
 
  typename std::enable_if<!std::is_const<pointer_t>::value, pointer_t>::type
  operator->() {
    return const_cast<remove_const_t<pointer_t>>(static_cast<const filter_iterator*>(this)->operator->());
  }
 
  add_const_t<pointer_t> operator->() const {
    return const_cast<add_const_t<pointer_t>>(&(operator*()));
  }
 
  size_t size() const {
    if (filters_.empty()) {
      return container_.size();
    }
 
    if (size_c_ > 0) {
      return size_c_;
    }
    filter_iterator it = begin();
    size_t size = 0;
 
    auto end_iter = std::end(it);
    for (; it != end_iter; ++it) ++size;
    size_c_ = size;
    return size_c_;
  }
 
 
  bool empty() const {
    return size() == 0;
  }
 
 
  bool operator==(const filter_iterator& other) const {
    return (container_.size() == other.container_.size() && distance_ == other.distance_);
  }
 
  bool operator!=(const filter_iterator& other) const {
    return !(*this == other);
  }
 
  protected:
  void next() {
    if (it_ == std::end(container_)) {
      distance_ = container_.size();
      return;
    }
 
    do {
      it_ = std::next(it_);
      distance_++;
    } while(it_ != std::end(container_) &&
            !std::all_of(std::begin(filters_), std::end(filters_),
                         [this] (const filter_t& f) { return f(*it_); }));
 
  }
 
 
  mutable size_t size_c_ = 0;
  T container_;
  ITERATOR_T it_;
  std::vector<filter_t> filters_;
  typename filter_iterator::difference_type distance_ = 0;
};

template<class T, typename U = typename decay_t<T>::value_type,
         class CT = typename std::add_const<T>::type>
using const_filter_iterator = filter_iterator<CT, U, typename decay_t<CT>::const_iterator>;
 
// ----------------------------------------------------------------------------
// This part is taken from LLVM
// ----------------------------------------------------------------------------
 
template <typename IteratorT>
class iterator_range {
  public:
  using IteratorTy = IteratorT;
  iterator_range(IteratorT&& it_begin, IteratorT&& it_end)
      : begin_(std::forward<IteratorT>(it_begin)),
        end_(std::forward<IteratorT>(it_end)) {}
 
  IteratorT begin() const { return begin_; }
  IteratorT end() const { return end_; }
  bool empty() const { return begin_ == end_; }
 
  typename IteratorT::value_type at(typename IteratorT::difference_type pos) const {
    static_assert(IsRandomAccess, "at() needs random access iterator");
    auto it = begin_;
    std::advance(it, pos);
    return *it;
  }
 
  typename IteratorT::value_type operator[](typename IteratorT::difference_type pos) const {
    return at(pos);
  }
 
  std::ptrdiff_t size() const {
    return std::distance(begin_, end_);
  }
 
  protected:
  enum {
    IsRandomAccess = std::is_base_of<std::random_access_iterator_tag,
                                      typename IteratorT::iterator_category>::value,
    IsBidirectional = std::is_base_of<std::bidirectional_iterator_tag,
                                      typename IteratorT::iterator_category>::value,
  };
  private:
  IteratorT begin_;
  IteratorT end_;
};
 
template <class T> iterator_range<T> make_range(T&& x, T&& y) {
  return iterator_range<T>(std::forward<T>(x), std::forward<T>(y));
}
 

template <typename DerivedT, typename IteratorCategoryT, typename T,
          typename DifferenceTypeT = std::ptrdiff_t, typename PointerT = T *,
          typename ReferenceT = T &>
class iterator_facade_base {
public:
  using iterator_category = IteratorCategoryT;
  using value_type = T;
  using difference_type = DifferenceTypeT;
  using pointer = PointerT;
  using reference = ReferenceT;
 
protected:
  enum {
    IsRandomAccess = std::is_base_of<std::random_access_iterator_tag,
                                     IteratorCategoryT>::value,
    IsBidirectional = std::is_base_of<std::bidirectional_iterator_tag,
                                      IteratorCategoryT>::value,
  };

  class ReferenceProxy {
    friend iterator_facade_base;
 
    DerivedT I;
 
    ReferenceProxy(DerivedT I) : I(std::move(I)) {}
 
  public:
    operator ReferenceT() const { return *I; }
  };

  class PointerProxy {
    friend iterator_facade_base;
 
    ReferenceT R;
 
    template <typename RefT>
    PointerProxy(RefT &&R) : R(std::forward<RefT>(R)) {}
 
  public:
    PointerT operator->() const { return &R; }
  };
 
public:
  DerivedT operator+(DifferenceTypeT n) const {
    static_assert(std::is_base_of<iterator_facade_base, DerivedT>::value,
                  "Must pass the derived type to this template!");
    static_assert(
        IsRandomAccess,
        "The '+' operator is only defined for random access iterators.");
    DerivedT tmp = *static_cast<const DerivedT *>(this);
    tmp += n;
    return tmp;
  }
  friend DerivedT operator+(DifferenceTypeT n, const DerivedT &i) {
    static_assert(
        IsRandomAccess,
        "The '+' operator is only defined for random access iterators.");
    return i + n;
  }
  DerivedT operator-(DifferenceTypeT n) const {
    static_assert(
        IsRandomAccess,
        "The '-' operator is only defined for random access iterators.");
    DerivedT tmp = *static_cast<const DerivedT *>(this);
    tmp -= n;
    return tmp;
  }
 
  DerivedT &operator++() {
    static_assert(std::is_base_of<iterator_facade_base, DerivedT>::value,
                  "Must pass the derived type to this template!");
    return static_cast<DerivedT *>(this)->operator+=(1);
  }
  DerivedT operator++(int) {
    DerivedT tmp = *static_cast<DerivedT *>(this);
    ++*static_cast<DerivedT *>(this);
    return tmp;
  }
  DerivedT &operator--() {
    static_assert(
        IsBidirectional,
        "The decrement operator is only defined for bidirectional iterators.");
    return static_cast<DerivedT *>(this)->operator-=(1);
  }
  DerivedT operator--(int) {
    static_assert(
        IsBidirectional,
        "The decrement operator is only defined for bidirectional iterators.");
    DerivedT tmp = *static_cast<DerivedT *>(this);
    --*static_cast<DerivedT *>(this);
    return tmp;
  }
 
#ifndef __cpp_impl_three_way_comparison
  bool operator!=(const DerivedT &RHS) const {
    return !(static_cast<const DerivedT &>(*this) == RHS);
  }
#endif
 
  bool operator>(const DerivedT &RHS) const {
    static_assert(
        IsRandomAccess,
        "Relational operators are only defined for random access iterators.");
    return !(static_cast<const DerivedT &>(*this) < RHS) &&
           !(static_cast<const DerivedT &>(*this) == RHS);
  }
  bool operator<=(const DerivedT &RHS) const {
    static_assert(
        IsRandomAccess,
        "Relational operators are only defined for random access iterators.");
    return !(static_cast<const DerivedT &>(*this) > RHS);
  }
  bool operator>=(const DerivedT &RHS) const {
    static_assert(
        IsRandomAccess,
        "Relational operators are only defined for random access iterators.");
    return !(static_cast<const DerivedT &>(*this) < RHS);
  }
 
  PointerProxy operator->() const {
    return static_cast<const DerivedT *>(this)->operator*();
  }
  ReferenceProxy operator[](DifferenceTypeT n) const {
    static_assert(IsRandomAccess,
                  "Subscripting is only defined for random access iterators.");
    return static_cast<const DerivedT *>(this)->operator+(n);
  }
};

template <
    typename DerivedT, typename WrappedIteratorT,
    typename IteratorCategoryT =
        typename std::iterator_traits<WrappedIteratorT>::iterator_category,
    typename T = typename std::iterator_traits<WrappedIteratorT>::value_type,
    typename DifferenceTypeT =
        typename std::iterator_traits<WrappedIteratorT>::difference_type,
    typename PointerT = typename std::conditional<
        std::is_same<T, typename std::iterator_traits<
                            WrappedIteratorT>::value_type>::value,
        typename std::iterator_traits<WrappedIteratorT>::pointer, T *>,
    typename ReferenceT = typename std::conditional<
        std::is_same<T, typename std::iterator_traits<
                            WrappedIteratorT>::value_type>::value,
        typename std::iterator_traits<WrappedIteratorT>::reference, T &>::type>
class iterator_adaptor_base
    : public iterator_facade_base<DerivedT, IteratorCategoryT, T,
                                  DifferenceTypeT, PointerT, ReferenceT> {
  using BaseT = typename iterator_adaptor_base::iterator_facade_base;
 
protected:
  WrappedIteratorT I;
 
  iterator_adaptor_base() = default;
 
  explicit iterator_adaptor_base(WrappedIteratorT u) : I(std::move(u)) {
    static_assert(std::is_base_of<iterator_adaptor_base, DerivedT>::value,
                  "Must pass the derived type to this template!");
  }
 
  const WrappedIteratorT &wrapped() const { return I; }
 
public:
  using difference_type = DifferenceTypeT;
 
  DerivedT &operator+=(difference_type n) {
    static_assert(
        BaseT::IsRandomAccess,
        "The '+=' operator is only defined for random access iterators.");
    I += n;
    return *static_cast<DerivedT *>(this);
  }
  DerivedT &operator-=(difference_type n) {
    static_assert(
        BaseT::IsRandomAccess,
        "The '-=' operator is only defined for random access iterators.");
    I -= n;
    return *static_cast<DerivedT *>(this);
  }
  using BaseT::operator-;
  difference_type operator-(const DerivedT &RHS) const {
    static_assert(
        BaseT::IsRandomAccess,
        "The '-' operator is only defined for random access iterators.");
    return I - RHS.I;
  }
 
  // We have to explicitly provide ++ and -- rather than letting the facade
  // forward to += because WrappedIteratorT might not support +=.
  using BaseT::operator++;
  DerivedT &operator++() {
    ++I;
    return *static_cast<DerivedT *>(this);
  }
  using BaseT::operator--;
  DerivedT &operator--() {
    static_assert(
        BaseT::IsBidirectional,
        "The decrement operator is only defined for bidirectional iterators.");
    --I;
    return *static_cast<DerivedT *>(this);
  }
 
  friend bool operator==(const iterator_adaptor_base &LHS,
                         const iterator_adaptor_base &RHS) {
    return LHS.I == RHS.I;
  }
  friend bool operator<(const iterator_adaptor_base &LHS,
                        const iterator_adaptor_base &RHS) {
    static_assert(
        BaseT::IsRandomAccess,
        "Relational operators are only defined for random access iterators.");
    return LHS.I < RHS.I;
  }
 
  ReferenceT operator*() const { return *I; }
};

template <typename WrappedIteratorT,
          typename T = typename std::remove_reference<decltype(
              **std::declval<WrappedIteratorT>())>::type>
struct pointee_iterator
    : iterator_adaptor_base<
          pointee_iterator<WrappedIteratorT, T>, WrappedIteratorT,
          typename std::iterator_traits<WrappedIteratorT>::iterator_category,
          T> {
  pointee_iterator() = default;
  template <typename U>
  pointee_iterator(U &&u)
      : pointee_iterator::iterator_adaptor_base(std::forward<U &&>(u)) {}
 
  T &operator*() const { return **this->I; }
};
 
template <typename RangeT, typename WrappedIteratorT =
                               decltype(std::begin(std::declval<RangeT>()))>
iterator_range<pointee_iterator<WrappedIteratorT>>
make_pointee_range(RangeT &&Range) {
  using PointeeIteratorT = pointee_iterator<WrappedIteratorT>;
  return make_range(PointeeIteratorT(std::begin(std::forward<RangeT>(Range))),
                    PointeeIteratorT(std::end(std::forward<RangeT>(Range))));
}
 
template <typename WrappedIteratorT,
          typename T = decltype(&*std::declval<WrappedIteratorT>())>
class pointer_iterator
    : public iterator_adaptor_base<
          pointer_iterator<WrappedIteratorT, T>, WrappedIteratorT,
          typename std::iterator_traits<WrappedIteratorT>::iterator_category,
          T> {
  mutable T Ptr;
 
public:
  pointer_iterator() = default;
 
  explicit pointer_iterator(WrappedIteratorT u)
      : pointer_iterator::iterator_adaptor_base(std::move(u)) {}
 
  T &operator*() const { return Ptr = &*this->I; }
};
 
template <typename RangeT, typename WrappedIteratorT =
                               decltype(std::begin(std::declval<RangeT>()))>
iterator_range<pointer_iterator<WrappedIteratorT>>
make_pointer_range(RangeT &&Range) {
  using PointerIteratorT = pointer_iterator<WrappedIteratorT>;
  return make_range(PointerIteratorT(std::begin(std::forward<RangeT>(Range))),
                    PointerIteratorT(std::end(std::forward<RangeT>(Range))));
}
 
template <typename WrappedIteratorT,
          typename T1 = typename std::remove_reference<decltype(
              **std::declval<WrappedIteratorT>())>::type,
          typename T2 = typename std::add_pointer<T1>::type>
using raw_pointer_iterator =
    pointer_iterator<pointee_iterator<WrappedIteratorT, T1>, T2>;
 
}
 
#endif