1// -*- C++ -*-
2//===----------------------------------------------------------------------===//
3//
4// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5// See https://llvm.org/LICENSE.txt for license information.
6// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7//
8//===----------------------------------------------------------------------===//
9
10#ifndef _LIBCPP___ITERATOR_ISTREAMBUF_ITERATOR_H
11#define _LIBCPP___ITERATOR_ISTREAMBUF_ITERATOR_H
12
13#include <__config>
14#include <__iterator/default_sentinel.h>
15#include <__iterator/iterator.h>
16#include <__iterator/iterator_traits.h>
17#include <iosfwd> // for forward declaration of basic_streambuf
18
19#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
20#  pragma GCC system_header
21#endif
22
23_LIBCPP_BEGIN_NAMESPACE_STD
24
25_LIBCPP_SUPPRESS_DEPRECATED_PUSH
26template<class _CharT, class _Traits>
27class _LIBCPP_TEMPLATE_VIS istreambuf_iterator
28#if _LIBCPP_STD_VER <= 14 || !defined(_LIBCPP_ABI_NO_ITERATOR_BASES)
29    : public iterator<input_iterator_tag, _CharT,
30                      typename _Traits::off_type, _CharT*,
31                      _CharT>
32#endif
33{
34_LIBCPP_SUPPRESS_DEPRECATED_POP
35public:
36    typedef input_iterator_tag              iterator_category;
37    typedef _CharT                          value_type;
38    typedef typename _Traits::off_type      difference_type;
39    typedef _CharT*                         pointer;
40    typedef _CharT                          reference;
41    typedef _CharT                          char_type;
42    typedef _Traits                         traits_type;
43    typedef typename _Traits::int_type      int_type;
44    typedef basic_streambuf<_CharT,_Traits> streambuf_type;
45    typedef basic_istream<_CharT,_Traits>   istream_type;
46private:
47    mutable streambuf_type* __sbuf_;
48
49    class __proxy
50    {
51        char_type __keep_;
52        streambuf_type* __sbuf_;
53        _LIBCPP_INLINE_VISIBILITY
54        explicit __proxy(char_type __c, streambuf_type* __s)
55            : __keep_(__c), __sbuf_(__s) {}
56        friend class istreambuf_iterator;
57    public:
58        _LIBCPP_INLINE_VISIBILITY char_type operator*() const {return __keep_;}
59    };
60
61    _LIBCPP_INLINE_VISIBILITY
62    bool __test_for_eof() const
63    {
64        if (__sbuf_ && traits_type::eq_int_type(__sbuf_->sgetc(), traits_type::eof()))
65            __sbuf_ = nullptr;
66        return __sbuf_ == nullptr;
67    }
68public:
69    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR istreambuf_iterator() _NOEXCEPT : __sbuf_(nullptr) {}
70#if _LIBCPP_STD_VER > 17
71    _LIBCPP_INLINE_VISIBILITY constexpr istreambuf_iterator(default_sentinel_t) noexcept
72        : istreambuf_iterator() {}
73#endif // _LIBCPP_STD_VER > 17
74    _LIBCPP_INLINE_VISIBILITY istreambuf_iterator(istream_type& __s) _NOEXCEPT
75        : __sbuf_(__s.rdbuf()) {}
76    _LIBCPP_INLINE_VISIBILITY istreambuf_iterator(streambuf_type* __s) _NOEXCEPT
77        : __sbuf_(__s) {}
78    _LIBCPP_INLINE_VISIBILITY istreambuf_iterator(const __proxy& __p) _NOEXCEPT
79        : __sbuf_(__p.__sbuf_) {}
80
81    _LIBCPP_INLINE_VISIBILITY char_type  operator*() const
82        {return static_cast<char_type>(__sbuf_->sgetc());}
83    _LIBCPP_INLINE_VISIBILITY istreambuf_iterator& operator++()
84        {
85            __sbuf_->sbumpc();
86            return *this;
87        }
88    _LIBCPP_INLINE_VISIBILITY __proxy              operator++(int)
89        {
90            return __proxy(__sbuf_->sbumpc(), __sbuf_);
91        }
92
93    _LIBCPP_INLINE_VISIBILITY bool equal(const istreambuf_iterator& __b) const
94        {return __test_for_eof() == __b.__test_for_eof();}
95
96#if _LIBCPP_STD_VER > 17
97    friend _LIBCPP_HIDE_FROM_ABI bool operator==(const istreambuf_iterator& __i, default_sentinel_t) {
98      return __i.__test_for_eof();
99    }
100#endif // _LIBCPP_STD_VER > 17
101};
102
103template <class _CharT, class _Traits>
104inline _LIBCPP_INLINE_VISIBILITY
105bool operator==(const istreambuf_iterator<_CharT,_Traits>& __a,
106                const istreambuf_iterator<_CharT,_Traits>& __b)
107                {return __a.equal(__b);}
108
109#if _LIBCPP_STD_VER <= 17
110template <class _CharT, class _Traits>
111inline _LIBCPP_INLINE_VISIBILITY
112bool operator!=(const istreambuf_iterator<_CharT,_Traits>& __a,
113                const istreambuf_iterator<_CharT,_Traits>& __b)
114                {return !__a.equal(__b);}
115#endif // _LIBCPP_STD_VER <= 17
116
117_LIBCPP_END_NAMESPACE_STD
118
119#endif // _LIBCPP___ITERATOR_ISTREAMBUF_ITERATOR_H
120