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b32b8144 | 1 | // |
92f5a8d4 | 2 | // Copyright (c) 2016-2019 Vinnie Falco (vinnie dot falco at gmail dot com) |
b32b8144 FG |
3 | // |
4 | // Distributed under the Boost Software License, Version 1.0. (See accompanying | |
5 | // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) | |
6 | // | |
7 | // Official repository: https://github.com/boostorg/beast | |
8 | // | |
9 | ||
10 | #ifndef BOOST_BEAST_STRING_PARAM_HPP | |
11 | #define BOOST_BEAST_STRING_PARAM_HPP | |
12 | ||
20effc67 TL |
13 | #if defined(BOOST_BEAST_ALLOW_DEPRECATED) && !defined(BOOST_BEAST_DOXYGEN) |
14 | ||
15 | ||
b32b8144 FG |
16 | #include <boost/beast/core/detail/config.hpp> |
17 | #include <boost/beast/core/string.hpp> | |
18 | #include <boost/beast/core/static_string.hpp> | |
19 | #include <boost/beast/core/detail/static_ostream.hpp> | |
b32b8144 FG |
20 | #include <boost/optional.hpp> |
21 | ||
22 | namespace boost { | |
23 | namespace beast { | |
24 | ||
25 | /** A function parameter which efficiently converts to string. | |
26 | ||
27 | This is used as a function parameter type to allow callers | |
28 | notational convenience: objects other than strings may be | |
29 | passed in contexts where a string is expected. The conversion | |
30 | to string is made using `operator<<` to a non-dynamically | |
31 | allocated static buffer if possible, else to a `std::string` | |
32 | on overflow. | |
33 | ||
34 | To use it, modify your function signature to accept | |
35 | `string_param` and then extract the string inside the | |
36 | function: | |
37 | @code | |
38 | void print(string_param s) | |
39 | { | |
40 | std::cout << s.str(); | |
41 | } | |
42 | @endcode | |
43 | */ | |
44 | class string_param | |
45 | { | |
46 | string_view sv_; | |
47 | char buf_[128]; | |
48 | boost::optional<detail::static_ostream> os_; | |
49 | ||
50 | template<class T> | |
51 | typename std::enable_if< | |
52 | std::is_integral<T>::value>::type | |
53 | print(T const&); | |
54 | ||
55 | template<class T> | |
56 | typename std::enable_if< | |
57 | ! std::is_integral<T>::value && | |
58 | ! std::is_convertible<T, string_view>::value | |
59 | >::type | |
60 | print(T const&); | |
61 | ||
62 | void | |
63 | print(string_view); | |
64 | ||
65 | template<class T> | |
66 | typename std::enable_if< | |
67 | std::is_integral<T>::value>::type | |
68 | print_1(T const&); | |
69 | ||
70 | template<class T> | |
71 | typename std::enable_if< | |
72 | ! std::is_integral<T>::value>::type | |
73 | print_1(T const&); | |
74 | ||
75 | void | |
76 | print_n() | |
77 | { | |
78 | } | |
79 | ||
80 | template<class T0, class... TN> | |
81 | void | |
82 | print_n(T0 const&, TN const&...); | |
83 | ||
84 | template<class T0, class T1, class... TN> | |
85 | void | |
86 | print(T0 const&, T1 const&, TN const&...); | |
87 | ||
88 | public: | |
89 | /// Copy constructor (disallowed) | |
90 | string_param(string_param const&) = delete; | |
91 | ||
92 | /// Copy assignment (disallowed) | |
93 | string_param& operator=(string_param const&) = delete; | |
94 | ||
95 | /** Constructor | |
96 | ||
97 | This function constructs a string as if by concatenating | |
98 | the result of streaming each argument in order into an | |
99 | output stream. It is used as a notational convenience | |
100 | at call sites which expect a parameter with the semantics | |
101 | of a @ref string_view. | |
102 | ||
103 | The implementation uses a small, internal static buffer | |
104 | to avoid memory allocations especially for the case where | |
105 | the list of arguments to be converted consists of a single | |
106 | integral type. | |
107 | ||
108 | @param args One or more arguments to convert | |
109 | */ | |
110 | template<class... Args> | |
111 | string_param(Args const&... args); | |
112 | ||
113 | /// Returns the contained string | |
114 | string_view | |
115 | str() const | |
116 | { | |
117 | return sv_; | |
118 | } | |
119 | ||
120 | /// Implicit conversion to @ref string_view | |
121 | operator string_view const() const | |
122 | { | |
123 | return sv_; | |
124 | } | |
125 | }; | |
126 | ||
127 | } // beast | |
128 | } // boost | |
129 | ||
92f5a8d4 | 130 | #include <boost/beast/core/impl/string_param.hpp> |
b32b8144 | 131 | |
20effc67 TL |
132 | #endif // defined(BOOST_BEAST_ALLOW_DEPRECATED) && !BOOST_BEAST_DOXYGEN |
133 | ||
b32b8144 | 134 | #endif |