ext-fmt/include/fmt/ostream.h
2023-12-23 15:00:28 -08:00

246 lines
7.1 KiB
C++

// Formatting library for C++ - std::ostream support
//
// Copyright (c) 2012 - present, Victor Zverovich
// All rights reserved.
//
// For the license information refer to format.h.
#ifndef FMT_OSTREAM_H_
#define FMT_OSTREAM_H_
#include <fstream> // std::filebuf
#ifdef _WIN32
# ifdef __GLIBCXX__
# include <ext/stdio_filebuf.h>
# include <ext/stdio_sync_filebuf.h>
# endif
# include <io.h>
#endif
#include "format.h"
FMT_BEGIN_NAMESPACE
namespace detail {
template <typename Streambuf> class formatbuf : public Streambuf {
private:
using char_type = typename Streambuf::char_type;
using streamsize = decltype(std::declval<Streambuf>().sputn(nullptr, 0));
using int_type = typename Streambuf::int_type;
using traits_type = typename Streambuf::traits_type;
buffer<char_type>& buffer_;
public:
explicit formatbuf(buffer<char_type>& buf) : buffer_(buf) {}
protected:
// The put area is always empty. This makes the implementation simpler and has
// the advantage that the streambuf and the buffer are always in sync and
// sputc never writes into uninitialized memory. A disadvantage is that each
// call to sputc always results in a (virtual) call to overflow. There is no
// disadvantage here for sputn since this always results in a call to xsputn.
auto overflow(int_type ch) -> int_type override {
if (!traits_type::eq_int_type(ch, traits_type::eof()))
buffer_.push_back(static_cast<char_type>(ch));
return ch;
}
auto xsputn(const char_type* s, streamsize count) -> streamsize override {
buffer_.append(s, s + count);
return count;
}
};
// Generate a unique explicit instantion in every translation unit using a tag
// type in an anonymous namespace.
namespace {
struct file_access_tag {};
} // namespace
template <typename Tag, typename BufType, FILE* BufType::*FileMemberPtr>
class file_access {
friend auto get_file(BufType& obj) -> FILE* { return obj.*FileMemberPtr; }
};
#if FMT_MSC_VERSION
template class file_access<file_access_tag, std::filebuf,
&std::filebuf::_Myfile>;
auto get_file(std::filebuf&) -> FILE*;
#endif
inline auto write_ostream_unicode(std::ostream& os, fmt::string_view data)
-> bool {
FILE* f = nullptr;
#if FMT_MSC_VERSION
if (auto* buf = dynamic_cast<std::filebuf*>(os.rdbuf()))
f = get_file(*buf);
else
return false;
#elif defined(_WIN32) && defined(__GLIBCXX__)
auto* rdbuf = os.rdbuf();
if (auto* sfbuf = dynamic_cast<__gnu_cxx::stdio_sync_filebuf<char>*>(rdbuf))
f = sfbuf->file();
else if (auto* fbuf = dynamic_cast<__gnu_cxx::stdio_filebuf<char>*>(rdbuf))
f = fbuf->file();
else
return false;
#else
ignore_unused(os, data, f);
#endif
#ifdef _WIN32
if (f) {
int fd = _fileno(f);
if (_isatty(fd)) {
os.flush();
return write_console(fd, data);
}
}
#endif
return false;
}
inline auto write_ostream_unicode(std::wostream&,
fmt::basic_string_view<wchar_t>) -> bool {
return false;
}
// Write the content of buf to os.
// It is a separate function rather than a part of vprint to simplify testing.
template <typename Char>
void write_buffer(std::basic_ostream<Char>& os, buffer<Char>& buf) {
const Char* buf_data = buf.data();
using unsigned_streamsize = std::make_unsigned<std::streamsize>::type;
unsigned_streamsize size = buf.size();
unsigned_streamsize max_size = to_unsigned(max_value<std::streamsize>());
do {
unsigned_streamsize n = size <= max_size ? size : max_size;
os.write(buf_data, static_cast<std::streamsize>(n));
buf_data += n;
size -= n;
} while (size != 0);
}
template <typename Char, typename T>
void format_value(buffer<Char>& buf, const T& value) {
auto&& format_buf = formatbuf<std::basic_streambuf<Char>>(buf);
auto&& output = std::basic_ostream<Char>(&format_buf);
#if !defined(FMT_STATIC_THOUSANDS_SEPARATOR)
output.imbue(std::locale::classic()); // The default is always unlocalized.
#endif
output << value;
output.exceptions(std::ios_base::failbit | std::ios_base::badbit);
}
template <typename T> struct streamed_view {
const T& value;
};
} // namespace detail
// Formats an object of type T that has an overloaded ostream operator<<.
template <typename Char>
struct basic_ostream_formatter : formatter<basic_string_view<Char>, Char> {
void set_debug_format() = delete;
template <typename T, typename OutputIt>
auto format(const T& value, basic_format_context<OutputIt, Char>& ctx) const
-> OutputIt {
auto buffer = basic_memory_buffer<Char>();
detail::format_value(buffer, value);
return formatter<basic_string_view<Char>, Char>::format(
{buffer.data(), buffer.size()}, ctx);
}
};
using ostream_formatter = basic_ostream_formatter<char>;
template <typename T, typename Char>
struct formatter<detail::streamed_view<T>, Char>
: basic_ostream_formatter<Char> {
template <typename OutputIt>
auto format(detail::streamed_view<T> view,
basic_format_context<OutputIt, Char>& ctx) const -> OutputIt {
return basic_ostream_formatter<Char>::format(view.value, ctx);
}
};
/**
\rst
Returns a view that formats `value` via an ostream ``operator<<``.
**Example**::
fmt::print("Current thread id: {}\n",
fmt::streamed(std::this_thread::get_id()));
\endrst
*/
template <typename T>
constexpr auto streamed(const T& value) -> detail::streamed_view<T> {
return {value};
}
namespace detail {
inline void vprint_directly(std::ostream& os, string_view format_str,
format_args args) {
auto buffer = memory_buffer();
detail::vformat_to(buffer, format_str, args);
detail::write_buffer(os, buffer);
}
} // namespace detail
FMT_EXPORT template <typename Char>
void vprint(std::basic_ostream<Char>& os,
basic_string_view<type_identity_t<Char>> format_str,
basic_format_args<buffer_context<type_identity_t<Char>>> args) {
auto buffer = basic_memory_buffer<Char>();
detail::vformat_to(buffer, format_str, args);
if (detail::write_ostream_unicode(os, {buffer.data(), buffer.size()})) return;
detail::write_buffer(os, buffer);
}
/**
\rst
Prints formatted data to the stream *os*.
**Example**::
fmt::print(cerr, "Don't {}!", "panic");
\endrst
*/
FMT_EXPORT template <typename... T>
void print(std::ostream& os, format_string<T...> fmt, T&&... args) {
const auto& vargs = fmt::make_format_args(args...);
if (detail::is_utf8())
vprint(os, fmt, vargs);
else
detail::vprint_directly(os, fmt, vargs);
}
FMT_EXPORT
template <typename... Args>
void print(std::wostream& os,
basic_format_string<wchar_t, type_identity_t<Args>...> fmt,
Args&&... args) {
vprint(os, fmt, fmt::make_format_args<buffer_context<wchar_t>>(args...));
}
FMT_EXPORT template <typename... T>
void println(std::ostream& os, format_string<T...> fmt, T&&... args) {
fmt::print(os, "{}\n", fmt::format(fmt, std::forward<T>(args)...));
}
FMT_EXPORT
template <typename... Args>
void println(std::wostream& os,
basic_format_string<wchar_t, type_identity_t<Args>...> fmt,
Args&&... args) {
print(os, L"{}\n", fmt::format(fmt, std::forward<Args>(args)...));
}
FMT_END_NAMESPACE
#endif // FMT_OSTREAM_H_