| 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_ |