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// 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 <ostream>
#include "format.h"
FMT_BEGIN_NAMESPACE
template <typename Char> class basic_printf_parse_context;
template <typename OutputIt, typename Char> class basic_printf_context;
namespace detail {
template <class Char> class formatbuf : public std::basic_streambuf<Char> {
private:
using int_type = typename std::basic_streambuf<Char>::int_type;
using traits_type = typename std::basic_streambuf<Char>::traits_type;
buffer<Char>& buffer_;
public:
formatbuf(buffer<Char>& buf) : buffer_(buf) {}
protected:
// The put-area is actually 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. The obvious
// 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.
int_type overflow(int_type ch = traits_type::eof()) FMT_OVERRIDE {
if (!traits_type::eq_int_type(ch, traits_type::eof()))
buffer_.push_back(static_cast<Char>(ch));
return ch;
}
std::streamsize xsputn(const Char* s, std::streamsize count) FMT_OVERRIDE {
buffer_.append(s, s + count);
return count;
}
};
struct converter {
template <typename T, FMT_ENABLE_IF(is_integral<T>::value)> converter(T);
};
template <typename Char> struct test_stream : std::basic_ostream<Char> {
private:
void_t<> operator<<(converter);
};
// Hide insertion operators for built-in types.
template <typename Char, typename Traits>
void_t<> operator<<(std::basic_ostream<Char, Traits>&, Char);
template <typename Char, typename Traits>
void_t<> operator<<(std::basic_ostream<Char, Traits>&, char);
template <typename Traits>
void_t<> operator<<(std::basic_ostream<char, Traits>&, char);
template <typename Traits>
void_t<> operator<<(std::basic_ostream<char, Traits>&, signed char);
template <typename Traits>
void_t<> operator<<(std::basic_ostream<char, Traits>&, unsigned char);
// Checks if T has a user-defined operator<< (e.g. not a member of
// std::ostream).
template <typename T, typename Char> class is_streamable {
private:
template <typename U>
static bool_constant<!std::is_same<decltype(std::declval<test_stream<Char>&>()
<< std::declval<U>()),
void_t<>>::value>
test(int);
template <typename> static std::false_type test(...);
using result = decltype(test<T>(0));
public:
static const bool value = result::value;
};
// Write the content of buf to os.
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,
locale_ref loc = locale_ref()) {
formatbuf<Char> format_buf(buf);
std::basic_ostream<Char> output(&format_buf);
#if !defined(FMT_STATIC_THOUSANDS_SEPARATOR)
if (loc) output.imbue(loc.get<std::locale>());
#endif
output << value;
output.exceptions(std::ios_base::failbit | std::ios_base::badbit);
buf.try_resize(buf.size());
}
// Formats an object of type T that has an overloaded ostream operator<<.
template <typename T, typename Char>
struct fallback_formatter<T, Char, enable_if_t<is_streamable<T, Char>::value>>
: private formatter<basic_string_view<Char>, Char> {
FMT_CONSTEXPR auto parse(basic_format_parse_context<Char>& ctx)
-> decltype(ctx.begin()) {
return formatter<basic_string_view<Char>, Char>::parse(ctx);
}
template <typename ParseCtx,
FMT_ENABLE_IF(std::is_same<
ParseCtx, basic_printf_parse_context<Char>>::value)>
auto parse(ParseCtx& ctx) -> decltype(ctx.begin()) {
return ctx.begin();
}
template <typename OutputIt>
auto format(const T& value, basic_format_context<OutputIt, Char>& ctx)
-> OutputIt {
basic_memory_buffer<Char> buffer;
format_value(buffer, value, ctx.locale());
basic_string_view<Char> str(buffer.data(), buffer.size());
return formatter<basic_string_view<Char>, Char>::format(str, ctx);
}
template <typename OutputIt>
auto format(const T& value, basic_printf_context<OutputIt, Char>& ctx)
-> OutputIt {
basic_memory_buffer<Char> buffer;
format_value(buffer, value, ctx.locale());
return std::copy(buffer.begin(), buffer.end(), ctx.out());
}
};
} // namespace detail
template <typename Char>
void vprint(std::basic_ostream<Char>& os, basic_string_view<Char> format_str,
basic_format_args<buffer_context<type_identity_t<Char>>> args) {
basic_memory_buffer<Char> buffer;
detail::vformat_to(buffer, format_str, args);
detail::write_buffer(os, buffer);
}
/**
\rst
Prints formatted data to the stream *os*.
**Example**::
fmt::print(cerr, "Don't {}!", "panic");
\endrst
*/
template <typename S, typename... Args,
typename Char = enable_if_t<detail::is_string<S>::value, char_t<S>>>
void print(std::basic_ostream<Char>& os, const S& format_str, Args&&... args) {
vprint(os, to_string_view(format_str),
fmt::make_args_checked<Args...>(format_str, args...));
}
FMT_END_NAMESPACE
#endif // FMT_OSTREAM_H_
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