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05aa7e19 JG |
1 | // Formatting library for C++ - std::ostream support |
2 | // | |
3 | // Copyright (c) 2012 - present, Victor Zverovich | |
4 | // All rights reserved. | |
5 | // | |
6 | // For the license information refer to format.h. | |
7 | ||
8 | #ifndef FMT_OSTREAM_H_ | |
9 | #define FMT_OSTREAM_H_ | |
10 | ||
11 | #include <ostream> | |
12 | ||
13 | #include "format.h" | |
14 | ||
15 | FMT_BEGIN_NAMESPACE | |
16 | ||
17 | template <typename OutputIt, typename Char> class basic_printf_context; | |
18 | ||
19 | namespace detail { | |
20 | ||
21 | // Checks if T has a user-defined operator<<. | |
22 | template <typename T, typename Char, typename Enable = void> | |
23 | class is_streamable { | |
24 | private: | |
25 | template <typename U> | |
26 | static auto test(int) | |
27 | -> bool_constant<sizeof(std::declval<std::basic_ostream<Char>&>() | |
28 | << std::declval<U>()) != 0>; | |
29 | ||
30 | template <typename> static auto test(...) -> std::false_type; | |
31 | ||
32 | using result = decltype(test<T>(0)); | |
33 | ||
34 | public: | |
35 | is_streamable() = default; | |
36 | ||
37 | static const bool value = result::value; | |
38 | }; | |
39 | ||
40 | // Formatting of built-in types and arrays is intentionally disabled because | |
41 | // it's handled by standard (non-ostream) formatters. | |
42 | template <typename T, typename Char> | |
43 | struct is_streamable< | |
44 | T, Char, | |
45 | enable_if_t< | |
46 | std::is_arithmetic<T>::value || std::is_array<T>::value || | |
47 | std::is_pointer<T>::value || std::is_same<T, char8_type>::value || | |
48 | std::is_same<T, std::basic_string<Char>>::value || | |
49 | std::is_same<T, std_string_view<Char>>::value || | |
50 | (std::is_convertible<T, int>::value && !std::is_enum<T>::value)>> | |
51 | : std::false_type {}; | |
52 | ||
53 | // Write the content of buf to os. | |
54 | // It is a separate function rather than a part of vprint to simplify testing. | |
55 | template <typename Char> | |
56 | void write_buffer(std::basic_ostream<Char>& os, buffer<Char>& buf) { | |
57 | const Char* buf_data = buf.data(); | |
58 | using unsigned_streamsize = std::make_unsigned<std::streamsize>::type; | |
59 | unsigned_streamsize size = buf.size(); | |
60 | unsigned_streamsize max_size = to_unsigned(max_value<std::streamsize>()); | |
61 | do { | |
62 | unsigned_streamsize n = size <= max_size ? size : max_size; | |
63 | os.write(buf_data, static_cast<std::streamsize>(n)); | |
64 | buf_data += n; | |
65 | size -= n; | |
66 | } while (size != 0); | |
67 | } | |
68 | ||
69 | template <typename Char, typename T> | |
70 | void format_value(buffer<Char>& buf, const T& value, | |
71 | locale_ref loc = locale_ref()) { | |
72 | auto&& format_buf = formatbuf<std::basic_streambuf<Char>>(buf); | |
73 | auto&& output = std::basic_ostream<Char>(&format_buf); | |
74 | #if !defined(FMT_STATIC_THOUSANDS_SEPARATOR) | |
75 | if (loc) output.imbue(loc.get<std::locale>()); | |
76 | #endif | |
77 | output << value; | |
78 | output.exceptions(std::ios_base::failbit | std::ios_base::badbit); | |
79 | buf.try_resize(buf.size()); | |
80 | } | |
81 | ||
82 | // Formats an object of type T that has an overloaded ostream operator<<. | |
83 | template <typename T, typename Char> | |
84 | struct fallback_formatter<T, Char, enable_if_t<is_streamable<T, Char>::value>> | |
85 | : private formatter<basic_string_view<Char>, Char> { | |
86 | using formatter<basic_string_view<Char>, Char>::parse; | |
87 | ||
88 | template <typename OutputIt> | |
89 | auto format(const T& value, basic_format_context<OutputIt, Char>& ctx) | |
90 | -> OutputIt { | |
91 | auto buffer = basic_memory_buffer<Char>(); | |
92 | format_value(buffer, value, ctx.locale()); | |
93 | return formatter<basic_string_view<Char>, Char>::format( | |
94 | {buffer.data(), buffer.size()}, ctx); | |
95 | } | |
96 | ||
97 | // DEPRECATED! | |
98 | template <typename OutputIt> | |
99 | auto format(const T& value, basic_printf_context<OutputIt, Char>& ctx) | |
100 | -> OutputIt { | |
101 | auto buffer = basic_memory_buffer<Char>(); | |
102 | format_value(buffer, value, ctx.locale()); | |
103 | return std::copy(buffer.begin(), buffer.end(), ctx.out()); | |
104 | } | |
105 | }; | |
106 | } // namespace detail | |
107 | ||
108 | FMT_MODULE_EXPORT | |
109 | template <typename Char> | |
110 | void vprint(std::basic_ostream<Char>& os, basic_string_view<Char> format_str, | |
111 | basic_format_args<buffer_context<type_identity_t<Char>>> args) { | |
112 | auto buffer = basic_memory_buffer<Char>(); | |
113 | detail::vformat_to(buffer, format_str, args); | |
114 | detail::write_buffer(os, buffer); | |
115 | } | |
116 | ||
117 | /** | |
118 | \rst | |
119 | Prints formatted data to the stream *os*. | |
120 | ||
121 | **Example**:: | |
122 | ||
123 | fmt::print(cerr, "Don't {}!", "panic"); | |
124 | \endrst | |
125 | */ | |
126 | FMT_MODULE_EXPORT | |
127 | template <typename S, typename... Args, | |
128 | typename Char = enable_if_t<detail::is_string<S>::value, char_t<S>>> | |
129 | void print(std::basic_ostream<Char>& os, const S& format_str, Args&&... args) { | |
130 | vprint(os, to_string_view(format_str), | |
131 | fmt::make_args_checked<Args...>(format_str, args...)); | |
132 | } | |
133 | FMT_END_NAMESPACE | |
134 | ||
135 | #endif // FMT_OSTREAM_H_ |