xref: /llvm-project/libcxx/include/__iterator/istreambuf_iterator.h (revision e99c4906e44ae3f921fa05356909d006cda8d954)
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 <__fwd/istream.h>
15 #include <__fwd/streambuf.h>
16 #include <__iterator/default_sentinel.h>
17 #include <__iterator/iterator.h>
18 #include <__iterator/iterator_traits.h>
19 #include <__string/char_traits.h>
20 #include <iosfwd>
21 
22 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
23 #  pragma GCC system_header
24 #endif
25 
26 _LIBCPP_BEGIN_NAMESPACE_STD
27 
28 _LIBCPP_SUPPRESS_DEPRECATED_PUSH
29 template <class _CharT, class _Traits>
30 class _LIBCPP_TEMPLATE_VIS istreambuf_iterator
31 #if _LIBCPP_STD_VER <= 14 || !defined(_LIBCPP_ABI_NO_ITERATOR_BASES)
32     : public iterator<input_iterator_tag, _CharT, typename _Traits::off_type, _CharT*, _CharT>
33 #endif
34 {
35   _LIBCPP_SUPPRESS_DEPRECATED_POP
36 
37 public:
38   typedef input_iterator_tag iterator_category;
39   typedef _CharT value_type;
40   typedef typename _Traits::off_type difference_type;
41   typedef _CharT* pointer;
42   typedef _CharT reference;
43   typedef _CharT char_type;
44   typedef _Traits traits_type;
45   typedef typename _Traits::int_type int_type;
46   typedef basic_streambuf<_CharT, _Traits> streambuf_type;
47   typedef basic_istream<_CharT, _Traits> istream_type;
48 
49 private:
50   mutable streambuf_type* __sbuf_;
51 
52   class __proxy {
53     char_type __keep_;
54     streambuf_type* __sbuf_;
55     _LIBCPP_HIDE_FROM_ABI explicit __proxy(char_type __c, streambuf_type* __s) : __keep_(__c), __sbuf_(__s) {}
56     friend class istreambuf_iterator;
57 
58   public:
59     _LIBCPP_HIDE_FROM_ABI char_type operator*() const { return __keep_; }
60   };
61 
62   _LIBCPP_HIDE_FROM_ABI bool __test_for_eof() const {
63     if (__sbuf_ && traits_type::eq_int_type(__sbuf_->sgetc(), traits_type::eof()))
64       __sbuf_ = nullptr;
65     return __sbuf_ == nullptr;
66   }
67 
68 public:
69   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR istreambuf_iterator() _NOEXCEPT : __sbuf_(nullptr) {}
70 #if _LIBCPP_STD_VER >= 20
71   _LIBCPP_HIDE_FROM_ABI constexpr istreambuf_iterator(default_sentinel_t) noexcept : istreambuf_iterator() {}
72 #endif // _LIBCPP_STD_VER >= 20
73   _LIBCPP_HIDE_FROM_ABI istreambuf_iterator(istream_type& __s) _NOEXCEPT : __sbuf_(__s.rdbuf()) {}
74   _LIBCPP_HIDE_FROM_ABI istreambuf_iterator(streambuf_type* __s) _NOEXCEPT : __sbuf_(__s) {}
75   _LIBCPP_HIDE_FROM_ABI istreambuf_iterator(const __proxy& __p) _NOEXCEPT : __sbuf_(__p.__sbuf_) {}
76 
77   _LIBCPP_HIDE_FROM_ABI char_type operator*() const { return static_cast<char_type>(__sbuf_->sgetc()); }
78   _LIBCPP_HIDE_FROM_ABI istreambuf_iterator& operator++() {
79     __sbuf_->sbumpc();
80     return *this;
81   }
82   _LIBCPP_HIDE_FROM_ABI __proxy operator++(int) { return __proxy(__sbuf_->sbumpc(), __sbuf_); }
83 
84   _LIBCPP_HIDE_FROM_ABI bool equal(const istreambuf_iterator& __b) const {
85     return __test_for_eof() == __b.__test_for_eof();
86   }
87 
88 #if _LIBCPP_STD_VER >= 20
89   friend _LIBCPP_HIDE_FROM_ABI bool operator==(const istreambuf_iterator& __i, default_sentinel_t) {
90     return __i.__test_for_eof();
91   }
92 #endif // _LIBCPP_STD_VER >= 20
93 };
94 
95 template <class _CharT, class _Traits>
96 inline _LIBCPP_HIDE_FROM_ABI bool
97 operator==(const istreambuf_iterator<_CharT, _Traits>& __a, const istreambuf_iterator<_CharT, _Traits>& __b) {
98   return __a.equal(__b);
99 }
100 
101 #if _LIBCPP_STD_VER <= 17
102 template <class _CharT, class _Traits>
103 inline _LIBCPP_HIDE_FROM_ABI bool
104 operator!=(const istreambuf_iterator<_CharT, _Traits>& __a, const istreambuf_iterator<_CharT, _Traits>& __b) {
105   return !__a.equal(__b);
106 }
107 #endif // _LIBCPP_STD_VER <= 17
108 
109 _LIBCPP_END_NAMESPACE_STD
110 
111 #endif // _LIBCPP___ITERATOR_ISTREAMBUF_ITERATOR_H
112