STL/stl/inc/iterator

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C++

// iterator standard header
// Copyright (c) Microsoft Corporation.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
#pragma once
#ifndef _ITERATOR_
#define _ITERATOR_
#include <yvals_core.h>
#if _STL_COMPILER_PREPROCESSOR
#include <iosfwd>
#include <xutility>
#pragma pack(push, _CRT_PACKING)
#pragma warning(push, _STL_WARNING_LEVEL)
#pragma warning(disable : _STL_DISABLED_WARNINGS)
_STL_DISABLE_CLANG_WARNINGS
#pragma push_macro("new")
#undef new
_STD_BEGIN
// CLASS TEMPLATE front_insert_iterator
template <class _Container>
class front_insert_iterator { // wrap pushes to front of container as output iterator
public:
using iterator_category = output_iterator_tag;
using value_type = void;
using difference_type = void;
using pointer = void;
using reference = void;
using container_type = _Container;
explicit front_insert_iterator(_Container& _Cont) : container(_STD addressof(_Cont)) {}
front_insert_iterator& operator=(const typename _Container::value_type& _Val) { // push value into container
container->push_front(_Val);
return *this;
}
front_insert_iterator& operator=(typename _Container::value_type&& _Val) { // push value into container
container->push_front(_STD move(_Val));
return *this;
}
_NODISCARD front_insert_iterator& operator*() { // pretend to return designated value
return *this;
}
front_insert_iterator& operator++() { // pretend to preincrement
return *this;
}
front_insert_iterator operator++(int) { // pretend to postincrement
return *this;
}
protected:
_Container* container; // pointer to container
};
// FUNCTION TEMPLATE front_inserter
template <class _Container>
_NODISCARD front_insert_iterator<_Container> front_inserter(_Container& _Cont) {
return front_insert_iterator<_Container>(_Cont);
}
// CLASS TEMPLATE insert_iterator
template <class _Container>
class insert_iterator { // wrap inserts into container as output iterator
public:
using iterator_category = output_iterator_tag;
using value_type = void;
using difference_type = void;
using pointer = void;
using reference = void;
using container_type = _Container;
insert_iterator(_Container& _Cont, typename _Container::iterator _Where)
: container(_STD addressof(_Cont)), iter(_Where) {}
insert_iterator& operator=(
const typename _Container::value_type& _Val) { // insert into container and increment stored iterator
iter = container->insert(iter, _Val);
++iter;
return *this;
}
insert_iterator& operator=(typename _Container::value_type&& _Val) { // push value into container
iter = container->insert(iter, _STD move(_Val));
++iter;
return *this;
}
_NODISCARD insert_iterator& operator*() { // pretend to return designated value
return *this;
}
insert_iterator& operator++() { // pretend to preincrement
return *this;
}
insert_iterator& operator++(int) { // pretend to postincrement
return *this;
}
protected:
_Container* container; // pointer to container
typename _Container::iterator iter; // iterator into container
};
// FUNCTION TEMPLATE inserter
template <class _Container>
_NODISCARD insert_iterator<_Container> inserter(_Container& _Cont, typename _Container::iterator _Where) {
return insert_iterator<_Container>(_Cont, _Where);
}
// CLASS TEMPLATE istream_iterator
template <class _Ty, class _Elem = char, class _Traits = char_traits<_Elem>, class _Diff = ptrdiff_t>
class istream_iterator { // wrap _Ty extracts from input stream as input iterator
public:
using iterator_category = input_iterator_tag;
using value_type = _Ty;
using difference_type = _Diff;
using pointer = const _Ty*;
using reference = const _Ty&;
using char_type = _Elem;
using traits_type = _Traits;
using istream_type = basic_istream<_Elem, _Traits>;
static_assert(conjunction_v<is_default_constructible<_Ty>, is_copy_constructible<_Ty>, is_copy_assignable<_Ty>>,
"istream_iterator<T> requires T to be default constructible, copy constructible, and copy assignable. "
"(N4835 [istream.iterator]/2)");
constexpr istream_iterator() {}
istream_iterator(istream_type& _Istr) : _Myistr(_STD addressof(_Istr)) {
_Getval();
}
_NODISCARD const _Ty& operator*() const {
_STL_ASSERT(_Myistr, "The stored stream pointer in_stream must be non-null");
return _Myval;
}
_NODISCARD const _Ty* operator->() const {
_STL_ASSERT(_Myistr, "The stored stream pointer in_stream must be non-null");
return _STD addressof(_Myval);
}
istream_iterator& operator++() {
_Getval();
return *this;
}
istream_iterator operator++(int) {
istream_iterator _Tmp = *this;
_Getval();
return _Tmp;
}
bool _Equal(const istream_iterator& _Right) const {
return _Myistr == _Right._Myistr;
}
private:
void _Getval() { // get a _Ty value if possible
_STL_ASSERT(_Myistr, "The stored stream pointer in_stream must be non-null");
if (!(*_Myistr >> _Myval)) {
_Myistr = nullptr;
}
}
istream_type* _Myistr{nullptr}; // pointer to input stream
_Ty _Myval{}; // lookahead value (valid if _Myistr is not null)
};
template <class _Ty, class _Elem, class _Traits, class _Diff>
_NODISCARD bool operator==(const istream_iterator<_Ty, _Elem, _Traits, _Diff>& _Left,
const istream_iterator<_Ty, _Elem, _Traits, _Diff>& _Right) {
return _Left._Equal(_Right);
}
template <class _Ty, class _Elem, class _Traits, class _Diff>
_NODISCARD bool operator!=(const istream_iterator<_Ty, _Elem, _Traits, _Diff>& _Left,
const istream_iterator<_Ty, _Elem, _Traits, _Diff>& _Right) {
return !(_Left == _Right);
}
// CLASS TEMPLATE ostream_iterator
template <class _Ty, class _Elem = char, class _Traits = char_traits<_Elem>>
class ostream_iterator { // wrap _Ty inserts to output stream as output iterator
public:
using iterator_category = output_iterator_tag;
using value_type = void;
using difference_type = void;
using pointer = void;
using reference = void;
using char_type = _Elem;
using traits_type = _Traits;
using ostream_type = basic_ostream<_Elem, _Traits>;
ostream_iterator(ostream_type& _Ostr, const _Elem* const _Delim = nullptr)
: _Mydelim(_Delim), _Myostr(_STD addressof(_Ostr)) {}
ostream_iterator& operator=(const _Ty& _Val) { // insert value into output stream, followed by delimiter
*_Myostr << _Val;
if (_Mydelim) {
*_Myostr << _Mydelim;
}
return *this;
}
_NODISCARD ostream_iterator& operator*() { // pretend to return designated value
return *this;
}
ostream_iterator& operator++() { // pretend to preincrement
return *this;
}
ostream_iterator& operator++(int) { // pretend to postincrement
return *this;
}
protected:
const _Elem* _Mydelim; // pointer to delimiter string (NB: not freed)
ostream_type* _Myostr; // pointer to output stream
};
// CLASS TEMPLATE istreambuf_iterator
template <class _Elem, class _Traits>
class istreambuf_iterator { // wrap stream buffer as input iterator
public:
using iterator_category = input_iterator_tag;
using value_type = _Elem;
using difference_type = typename _Traits::off_type;
using pointer = const _Elem*;
using reference = _Elem;
using char_type = _Elem;
using traits_type = _Traits;
using streambuf_type = basic_streambuf<_Elem, _Traits>;
using istream_type = basic_istream<_Elem, _Traits>;
using int_type = typename traits_type::int_type;
constexpr istreambuf_iterator() noexcept : _Strbuf(nullptr), _Got(true), _Val() {}
istreambuf_iterator(streambuf_type* _Sb) noexcept : _Strbuf(_Sb), _Got(!_Sb), _Val() {}
istreambuf_iterator(istream_type& _Istr) noexcept : _Strbuf(_Istr.rdbuf()), _Got(!_Strbuf), _Val() {}
private:
class _Istreambuf_proxy {
public:
_NODISCARD _Elem operator*() const {
return _Keep;
}
private:
friend istreambuf_iterator;
_Istreambuf_proxy(streambuf_type* _Strbuf_, _Elem _Keep_) : _Strbuf(_Strbuf_), _Keep(_Keep_) {}
streambuf_type* _Strbuf;
_Elem _Keep;
};
public:
istreambuf_iterator(const _Istreambuf_proxy& _Px) noexcept : _Strbuf(_Px._Strbuf), _Got(!_Strbuf), _Val() {}
_NODISCARD _Elem operator*() const {
if (!_Got) {
_Peek();
}
#if _ITERATOR_DEBUG_LEVEL == 2
_STL_VERIFY(_Strbuf, "istreambuf_iterator is not dereferenceable");
#endif // _ITERATOR_DEBUG_LEVEL == 2
return _Val;
}
istreambuf_iterator& operator++() {
#if _ITERATOR_DEBUG_LEVEL == 2
_STL_VERIFY(_Strbuf, "istreambuf_iterator is not incrementable");
#endif // _ITERATOR_DEBUG_LEVEL == 2
_Inc();
return *this;
}
_Istreambuf_proxy operator++(int) {
if (!_Got) {
_Peek();
}
_Istreambuf_proxy _Tmp{_Strbuf, _Val};
++*this;
return _Tmp;
}
_NODISCARD bool equal(const istreambuf_iterator& _Right) const {
if (!_Got) {
_Peek();
}
if (!_Right._Got) {
_Right._Peek();
}
return (!_Strbuf && !_Right._Strbuf) || (_Strbuf && _Right._Strbuf);
}
private:
void _Inc() { // skip to next input element
if (!_Strbuf || traits_type::eq_int_type(traits_type::eof(), _Strbuf->sbumpc())) {
_Strbuf = nullptr;
_Got = true;
} else {
_Got = false;
}
}
_Elem _Peek() const { // peek at next input element
int_type _Meta;
if (!_Strbuf || traits_type::eq_int_type(traits_type::eof(), _Meta = _Strbuf->sgetc())) {
_Strbuf = nullptr;
} else {
_Val = traits_type::to_char_type(_Meta);
}
_Got = true;
return _Val;
}
mutable streambuf_type* _Strbuf; // the wrapped stream buffer
mutable bool _Got; // true if _Val is valid
mutable _Elem _Val; // next element to deliver
};
template <class _Elem, class _Traits>
_NODISCARD bool operator==(
const istreambuf_iterator<_Elem, _Traits>& _Left, const istreambuf_iterator<_Elem, _Traits>& _Right) {
return _Left.equal(_Right);
}
template <class _Elem, class _Traits>
_NODISCARD bool operator!=(
const istreambuf_iterator<_Elem, _Traits>& _Left, const istreambuf_iterator<_Elem, _Traits>& _Right) {
return !(_Left == _Right);
}
// CLASS TEMPLATE ostreambuf_iterator
template <class _Elem, class _Traits>
class ostreambuf_iterator { // wrap stream buffer as output iterator
public:
using iterator_category = output_iterator_tag;
using value_type = void;
using difference_type = void;
using pointer = void;
using reference = void;
using char_type = _Elem;
using traits_type = _Traits;
using streambuf_type = basic_streambuf<_Elem, _Traits>;
using ostream_type = basic_ostream<_Elem, _Traits>;
ostreambuf_iterator(streambuf_type* _Sb) noexcept : _Failed(false), _Strbuf(_Sb) {}
ostreambuf_iterator(ostream_type& _Ostr) noexcept : _Failed(false), _Strbuf(_Ostr.rdbuf()) {}
ostreambuf_iterator& operator=(_Elem _Right) { // store element and increment
if (!_Strbuf || traits_type::eq_int_type(_Traits::eof(), _Strbuf->sputc(_Right))) {
_Failed = true;
}
return *this;
}
_NODISCARD ostreambuf_iterator& operator*() { // pretend to get designated element
return *this;
}
ostreambuf_iterator& operator++() { // pretend to preincrement
return *this;
}
ostreambuf_iterator& operator++(int) { // pretend to postincrement
return *this;
}
_NODISCARD bool failed() const noexcept {
return _Failed;
}
private:
bool _Failed; // true if any stores have failed
streambuf_type* _Strbuf; // the wrapped stream buffer
};
_STD_END
_STDEXT_BEGIN
using _STD iterator_traits;
using _STD size_t;
// CLASS TEMPLATE checked_array_iterator
template <class _Ptr>
class checked_array_iterator { // wrap a pointer with checking
static_assert(_STD is_pointer_v<_Ptr>, "checked_array_iterator requires pointers");
public:
using iterator_category = typename iterator_traits<_Ptr>::iterator_category;
using value_type = typename iterator_traits<_Ptr>::value_type;
using difference_type = typename iterator_traits<_Ptr>::difference_type;
using pointer = typename iterator_traits<_Ptr>::pointer;
using reference = typename iterator_traits<_Ptr>::reference;
constexpr checked_array_iterator() noexcept : _Myarray(nullptr), _Mysize(0), _Myindex(0) {}
constexpr checked_array_iterator(const _Ptr _Array, const size_t _Size, const size_t _Index = 0) noexcept
: _Myarray(_Array), _Mysize(_Size), _Myindex(_Index) {
_STL_VERIFY(_Index <= _Size, "checked_array_iterator construction index out of range");
}
_NODISCARD constexpr _Ptr base() const noexcept {
return _Myarray + _Myindex;
}
_NODISCARD constexpr reference operator*() const noexcept {
return *operator->();
}
_NODISCARD constexpr pointer operator->() const noexcept {
_STL_VERIFY(_Myarray, "cannot dereference value-initialized or null checked_array_iterator");
_STL_VERIFY(_Myindex < _Mysize, "cannot dereference end checked_array_iterator");
return _Myarray + _Myindex;
}
constexpr checked_array_iterator& operator++() noexcept {
_STL_VERIFY(_Myarray, "cannot increment value-initialized or null checked_array_iterator");
_STL_VERIFY(_Myindex < _Mysize, "cannot increment checked_array_iterator past end");
++_Myindex;
return *this;
}
constexpr checked_array_iterator operator++(int) noexcept {
checked_array_iterator _Tmp = *this;
++*this;
return _Tmp;
}
constexpr checked_array_iterator& operator--() noexcept {
_STL_VERIFY(_Myarray, "cannot decrement value-initialized or null checked_array_iterator");
_STL_VERIFY(_Myindex != 0, "cannot decrement checked_array_iterator before begin");
--_Myindex;
return *this;
}
constexpr checked_array_iterator operator--(int) noexcept {
checked_array_iterator _Tmp = *this;
--*this;
return _Tmp;
}
constexpr checked_array_iterator& operator+=(const difference_type _Off) noexcept {
if (_Off != 0) {
_STL_VERIFY(_Myarray, "cannot seek value-initialized or null checked_array_iterator");
}
if (_Off < 0) {
#pragma warning(suppress : 4146) // unary minus operator applied to unsigned type, result still unsigned
_STL_VERIFY(_Myindex >= -static_cast<size_t>(_Off), "cannot seek checked_array_iterator before begin");
}
if (_Off > 0) {
_STL_VERIFY(
_Mysize - _Myindex >= static_cast<size_t>(_Off), "cannot seek checked_array_iterator after end");
}
_Myindex += _Off;
return *this;
}
_NODISCARD constexpr checked_array_iterator operator+(const difference_type _Off) const noexcept {
checked_array_iterator _Tmp = *this;
_Tmp += _Off;
return _Tmp;
}
#ifndef __CUDACC__ // TRANSITION, VSO-568006
_NODISCARD
#endif // TRANSITION, VSO-568006
friend constexpr checked_array_iterator operator+(
const difference_type _Off, const checked_array_iterator<_Ptr>& _Next) noexcept {
return _Next + _Off;
}
constexpr checked_array_iterator& operator-=(const difference_type _Off) noexcept {
if (_Off != 0) {
_STL_VERIFY(_Myarray, "cannot seek value-initialized or null checked_array_iterator");
}
if (_Off > 0) {
_STL_VERIFY(_Myindex >= static_cast<size_t>(_Off), "cannot seek checked_array_iterator before begin");
}
if (_Off < 0) {
#pragma warning(suppress : 4146) // unary minus operator applied to unsigned type, result still unsigned
_STL_VERIFY(
_Mysize - _Myindex >= -static_cast<size_t>(_Off), "cannot seek checked_array_iterator after end");
}
_Myindex -= _Off;
return *this;
}
_NODISCARD constexpr checked_array_iterator operator-(const difference_type _Off) const noexcept {
checked_array_iterator _Tmp = *this;
_Tmp -= _Off;
return _Tmp;
}
_NODISCARD constexpr difference_type operator-(const checked_array_iterator& _Right) const noexcept {
_STL_VERIFY(_Myarray == _Right._Myarray && _Mysize == _Right._Mysize,
"cannot subtract incompatible checked_array_iterators");
return static_cast<difference_type>(_Myindex - _Right._Myindex);
}
_NODISCARD constexpr reference operator[](const difference_type _Off) const noexcept {
return *(*this + _Off);
}
_NODISCARD constexpr bool operator==(const checked_array_iterator& _Right) const noexcept {
_STL_VERIFY(_Myarray == _Right._Myarray && _Mysize == _Right._Mysize,
"cannot compare incompatible checked_array_iterators for equality");
return _Myindex == _Right._Myindex;
}
_NODISCARD constexpr bool operator!=(const checked_array_iterator& _Right) const noexcept {
return !(*this == _Right);
}
_NODISCARD constexpr bool operator<(const checked_array_iterator& _Right) const noexcept {
_STL_VERIFY(_Myarray == _Right._Myarray && _Mysize == _Right._Mysize,
"cannot compare incompatible checked_array_iterators");
return _Myindex < _Right._Myindex;
}
_NODISCARD constexpr bool operator>(const checked_array_iterator& _Right) const noexcept {
return _Right < *this;
}
_NODISCARD constexpr bool operator<=(const checked_array_iterator& _Right) const noexcept {
return !(_Right < *this);
}
_NODISCARD constexpr bool operator>=(const checked_array_iterator& _Right) const noexcept {
return !(*this < _Right);
}
friend constexpr void _Verify_range(
const checked_array_iterator& _First, const checked_array_iterator& _Last) noexcept {
_STL_VERIFY(_First._Myarray == _Last._Myarray && _First._Mysize == _Last._Mysize,
"mismatching checked_array_iterators");
_STL_VERIFY(_First._Myindex <= _Last._Myindex, "transposed checked_array_iterator range");
}
constexpr void _Verify_offset(const difference_type _Off) const noexcept {
if (_Off < 0) {
#pragma warning(suppress : 4146) // unary minus operator applied to unsigned type, result still unsigned
_STL_VERIFY(
_Myindex >= -static_cast<size_t>(_Off), "cannot seek checked_array_iterator iterator before begin");
}
if (_Off > 0) {
_STL_VERIFY(_Mysize - _Myindex >= static_cast<size_t>(_Off),
"cannot seek checked_array_iterator iterator after end");
}
}
using _Prevent_inheriting_unwrap = checked_array_iterator;
_NODISCARD constexpr _Ptr _Unwrapped() const noexcept {
return _Myarray + _Myindex;
}
constexpr void _Seek_to(_Ptr _It) noexcept {
_Myindex = static_cast<size_t>(_It - _Myarray);
}
private:
_Ptr _Myarray; // beginning of array
size_t _Mysize; // size of array
size_t _Myindex; // offset into array
};
template <class _Ptr>
_NODISCARD constexpr checked_array_iterator<_Ptr> make_checked_array_iterator(
const _Ptr _Array, const size_t _Size, const size_t _Index = 0) {
return checked_array_iterator<_Ptr>(_Array, _Size, _Index);
}
// CLASS TEMPLATE unchecked_array_iterator
template <class _Ptr>
class unchecked_array_iterator { // wrap a pointer without checking, to silence warnings
static_assert(_STD is_pointer_v<_Ptr>, "unchecked_array_iterator requires pointers");
public:
using iterator_category = typename iterator_traits<_Ptr>::iterator_category;
using value_type = typename iterator_traits<_Ptr>::value_type;
using difference_type = typename iterator_traits<_Ptr>::difference_type;
using pointer = typename iterator_traits<_Ptr>::pointer;
using reference = typename iterator_traits<_Ptr>::reference;
constexpr unchecked_array_iterator() noexcept : _Myptr(nullptr) {}
constexpr explicit unchecked_array_iterator(const _Ptr _Src) noexcept : _Myptr(_Src) {}
_NODISCARD constexpr _Ptr base() const noexcept {
return _Myptr;
}
_NODISCARD constexpr reference operator*() const noexcept {
return *_Myptr;
}
_NODISCARD constexpr pointer operator->() const noexcept {
return _Myptr;
}
constexpr unchecked_array_iterator& operator++() noexcept {
++_Myptr;
return *this;
}
constexpr unchecked_array_iterator operator++(int) noexcept {
unchecked_array_iterator _Tmp = *this;
++_Myptr;
return _Tmp;
}
constexpr unchecked_array_iterator& operator--() noexcept {
--_Myptr;
return *this;
}
constexpr unchecked_array_iterator operator--(int) noexcept {
unchecked_array_iterator _Tmp = *this;
--_Myptr;
return _Tmp;
}
constexpr unchecked_array_iterator& operator+=(const difference_type _Off) noexcept {
_Myptr += _Off;
return *this;
}
_NODISCARD constexpr unchecked_array_iterator operator+(const difference_type _Off) const noexcept {
unchecked_array_iterator _Tmp = *this;
_Tmp += _Off;
return _Tmp;
}
#ifndef __CUDACC__ // TRANSITION, VSO-568006
_NODISCARD
#endif // TRANSITION, VSO-568006
friend constexpr unchecked_array_iterator operator+(
const difference_type _Off, const unchecked_array_iterator& _Next) noexcept {
return _Next + _Off;
}
constexpr unchecked_array_iterator& operator-=(const difference_type _Off) noexcept {
return *this += -_Off;
}
_NODISCARD constexpr unchecked_array_iterator operator-(const difference_type _Off) const noexcept {
unchecked_array_iterator _Tmp = *this;
_Tmp -= _Off;
return _Tmp;
}
_NODISCARD constexpr difference_type operator-(const unchecked_array_iterator& _Right) const noexcept {
return _Myptr - _Right._Myptr;
}
_NODISCARD constexpr reference operator[](const difference_type _Off) const noexcept {
return *(*this + _Off);
}
_NODISCARD constexpr bool operator==(const unchecked_array_iterator& _Right) const noexcept {
return _Myptr == _Right._Myptr;
}
_NODISCARD constexpr bool operator!=(const unchecked_array_iterator& _Right) const noexcept {
return !(*this == _Right);
}
_NODISCARD constexpr bool operator<(const unchecked_array_iterator& _Right) const noexcept {
return _Myptr < _Right._Myptr;
}
_NODISCARD constexpr bool operator>(const unchecked_array_iterator& _Right) const noexcept {
return _Right < *this;
}
_NODISCARD constexpr bool operator<=(const unchecked_array_iterator& _Right) const noexcept {
return !(_Right < *this);
}
_NODISCARD constexpr bool operator>=(const unchecked_array_iterator& _Right) const noexcept {
return !(*this < _Right);
}
#if _ITERATOR_DEBUG_LEVEL != 0
friend constexpr void _Verify_range(
const unchecked_array_iterator _First, const unchecked_array_iterator _Last) noexcept {
_STD _Verify_range(_First._Myptr, _Last._Myptr);
}
#endif // _ITERATOR_DEBUG_LEVEL != 0
using _Prevent_inheriting_unwrap = unchecked_array_iterator;
static constexpr bool _Unwrap_when_unverified = true;
_NODISCARD constexpr _Ptr _Unwrapped() const noexcept {
return _Myptr;
}
constexpr void _Seek_to(_Ptr _It) noexcept {
_Myptr = _It;
}
private:
_Ptr _Myptr; // underlying pointer
};
template <class _Ptr>
_NODISCARD unchecked_array_iterator<_Ptr> make_unchecked_array_iterator(const _Ptr _It) noexcept {
return unchecked_array_iterator<_Ptr>(_It);
}
_STDEXT_END
#pragma pop_macro("new")
_STL_RESTORE_CLANG_WARNINGS
#pragma warning(pop)
#pragma pack(pop)
#endif // _STL_COMPILER_PREPROCESSOR
#endif // _ITERATOR_