// Formatting library for C++ - legacy printf implementation // // Copyright (c) 2012 - 2016, Victor Zverovich // All rights reserved. // // For the license information refer to format.h. #ifndef FMT_PRINTF_H_ #define FMT_PRINTF_H_ #include <algorithm> // std::max #include <limits> // std::numeric_limits #include "ostream.h" FMT_BEGIN_NAMESPACE namespace detail { // Checks if a value fits in int - used to avoid warnings about comparing // signed and unsigned integers. template <bool IsSigned> struct int_checker { template <typename T> static bool fits_in_int(T value) { unsigned max = max_value<int>(); return value <= max; } static bool fits_in_int(bool) { return true; } }; template <> struct int_checker<true> { template <typename T> static bool fits_in_int(T value) { return value >= (std::numeric_limits<int>::min)() && value <= max_value<int>(); } static bool fits_in_int(int) { return true; } }; class printf_precision_handler { public: template <typename T, FMT_ENABLE_IF(std::is_integral<T>::value)> int operator()(T value) { if (!int_checker<std::numeric_limits<T>::is_signed>::fits_in_int(value)) FMT_THROW(format_error("number is too big")); return (std::max)(static_cast<int>(value), 0); } template <typename T, FMT_ENABLE_IF(!std::is_integral<T>::value)> int operator()(T) { FMT_THROW(format_error("precision is not integer")); return 0; } }; // An argument visitor that returns true iff arg is a zero integer. class is_zero_int { public: template <typename T, FMT_ENABLE_IF(std::is_integral<T>::value)> bool operator()(T value) { return value == 0; } template <typename T, FMT_ENABLE_IF(!std::is_integral<T>::value)> bool operator()(T) { return false; } }; template <typename T> struct make_unsigned_or_bool : std::make_unsigned<T> {}; template <> struct make_unsigned_or_bool<bool> { using type = bool; }; template <typename T, typename Context> class arg_converter { private: using char_type = typename Context::char_type; basic_format_arg<Context>& arg_; char_type type_; public: arg_converter(basic_format_arg<Context>& arg, char_type type) : arg_(arg), type_(type) {} void operator()(bool value) { if (type_ != 's') operator()<bool>(value); } template <typename U, FMT_ENABLE_IF(std::is_integral<U>::value)> void operator()(U value) { bool is_signed = type_ == 'd' || type_ == 'i'; using target_type = conditional_t<std::is_same<T, void>::value, U, T>; if (const_check(sizeof(target_type) <= sizeof(int))) { // Extra casts are used to silence warnings. if (is_signed) { arg_ = detail::make_arg<Context>( static_cast<int>(static_cast<target_type>(value))); } else { using unsigned_type = typename make_unsigned_or_bool<target_type>::type; arg_ = detail::make_arg<Context>( static_cast<unsigned>(static_cast<unsigned_type>(value))); } } else { if (is_signed) { // glibc's printf doesn't sign extend arguments of smaller types: // std::printf("%lld", -42); // prints "4294967254" // but we don't have to do the same because it's a UB. arg_ = detail::make_arg<Context>(static_cast<long long>(value)); } else { arg_ = detail::make_arg<Context>( static_cast<typename make_unsigned_or_bool<U>::type>(value)); } } } template <typename U, FMT_ENABLE_IF(!std::is_integral<U>::value)> void operator()(U) {} // No conversion needed for non-integral types. }; // Converts an integer argument to T for printf, if T is an integral type. // If T is void, the argument is converted to corresponding signed or unsigned // type depending on the type specifier: 'd' and 'i' - signed, other - // unsigned). template <typename T, typename Context, typename Char> void convert_arg(basic_format_arg<Context>& arg, Char type) { visit_format_arg(arg_converter<T, Context>(arg, type), arg); } // Converts an integer argument to char for printf. template <typename Context> class char_converter { private: basic_format_arg<Context>& arg_; public: explicit char_converter(basic_format_arg<Context>& arg) : arg_(arg) {} template <typename T, FMT_ENABLE_IF(std::is_integral<T>::value)> void operator()(T value) { arg_ = detail::make_arg<Context>( static_cast<typename Context::char_type>(value)); } template <typename T, FMT_ENABLE_IF(!std::is_integral<T>::value)> void operator()(T) {} // No conversion needed for non-integral types. }; // An argument visitor that return a pointer to a C string if argument is a // string or null otherwise. template <typename Char> struct get_cstring { template <typename T> const Char* operator()(T) { return nullptr; } const Char* operator()(const Char* s) { return s; } }; // Checks if an argument is a valid printf width specifier and sets // left alignment if it is negative. template <typename Char> class printf_width_handler { private: using format_specs = basic_format_specs<Char>; format_specs& specs_; public: explicit printf_width_handler(format_specs& specs) : specs_(specs) {} template <typename T, FMT_ENABLE_IF(std::is_integral<T>::value)> unsigned operator()(T value) { auto width = static_cast<uint32_or_64_or_128_t<T>>(value); if (detail::is_negative(value)) { specs_.align = align::left; width = 0 - width; } unsigned int_max = max_value<int>(); if (width > int_max) FMT_THROW(format_error("number is too big")); return static_cast<unsigned>(width); } template <typename T, FMT_ENABLE_IF(!std::is_integral<T>::value)> unsigned operator()(T) { FMT_THROW(format_error("width is not integer")); return 0; } }; template <typename Char, typename Context> void vprintf(buffer<Char>& buf, basic_string_view<Char> format, basic_format_args<Context> args) { Context(buffer_appender<Char>(buf), format, args).format(); } } // namespace detail // For printing into memory_buffer. template <typename Char, typename Context> FMT_DEPRECATED void printf(detail::buffer<Char>& buf, basic_string_view<Char> format, basic_format_args<Context> args) { return detail::vprintf(buf, format, args); } using detail::vprintf; template <typename Char> class basic_printf_parse_context : public basic_format_parse_context<Char> { using basic_format_parse_context<Char>::basic_format_parse_context; }; template <typename OutputIt, typename Char> class basic_printf_context; /** \rst The ``printf`` argument formatter. \endrst */ template <typename OutputIt, typename Char> class printf_arg_formatter : public detail::arg_formatter_base<OutputIt, Char> { public: using iterator = OutputIt; private: using char_type = Char; using base = detail::arg_formatter_base<OutputIt, Char>; using context_type = basic_printf_context<OutputIt, Char>; context_type& context_; void write_null_pointer(char) { this->specs()->type = 0; this->write("(nil)"); } void write_null_pointer(wchar_t) { this->specs()->type = 0; this->write(L"(nil)"); } public: using format_specs = typename base::format_specs; /** \rst Constructs an argument formatter object. *buffer* is a reference to the output buffer and *specs* contains format specifier information for standard argument types. \endrst */ printf_arg_formatter(iterator iter, format_specs& specs, context_type& ctx) : base(iter, &specs, detail::locale_ref()), context_(ctx) {} template <typename T, FMT_ENABLE_IF(fmt::detail::is_integral<T>::value)> iterator operator()(T value) { // MSVC2013 fails to compile separate overloads for bool and char_type so // use std::is_same instead. if (std::is_same<T, bool>::value) { format_specs& fmt_specs = *this->specs(); if (fmt_specs.type != 's') return base::operator()(value ? 1 : 0); fmt_specs.type = 0; this->write(value != 0); } else if (std::is_same<T, char_type>::value) { format_specs& fmt_specs = *this->specs(); if (fmt_specs.type && fmt_specs.type != 'c') return (*this)(static_cast<int>(value)); fmt_specs.sign = sign::none; fmt_specs.alt = false; fmt_specs.fill[0] = ' '; // Ignore '0' flag for char types. // align::numeric needs to be overwritten here since the '0' flag is // ignored for non-numeric types if (fmt_specs.align == align::none || fmt_specs.align == align::numeric) fmt_specs.align = align::right; return base::operator()(value); } else { return base::operator()(value); } return this->out(); } template <typename T, FMT_ENABLE_IF(std::is_floating_point<T>::value)> iterator operator()(T value) { return base::operator()(value); } /** Formats a null-terminated C string. */ iterator operator()(const char* value) { if (value) base::operator()(value); else if (this->specs()->type == 'p') write_null_pointer(char_type()); else this->write("(null)"); return this->out(); } /** Formats a null-terminated wide C string. */ iterator operator()(const wchar_t* value) { if (value) base::operator()(value); else if (this->specs()->type == 'p') write_null_pointer(char_type()); else this->write(L"(null)"); return this->out(); } iterator operator()(basic_string_view<char_type> value) { return base::operator()(value); } iterator operator()(monostate value) { return base::operator()(value); } /** Formats a pointer. */ iterator operator()(const void* value) { if (value) return base::operator()(value); this->specs()->type = 0; write_null_pointer(char_type()); return this->out(); } /** Formats an argument of a custom (user-defined) type. */ iterator operator()(typename basic_format_arg<context_type>::handle handle) { handle.format(context_.parse_context(), context_); return this->out(); } }; template <typename T> struct printf_formatter { printf_formatter() = delete; template <typename ParseContext> auto parse(ParseContext& ctx) -> decltype(ctx.begin()) { return ctx.begin(); } template <typename FormatContext> auto format(const T& value, FormatContext& ctx) -> decltype(ctx.out()) { detail::format_value(detail::get_container(ctx.out()), value); return ctx.out(); } }; /** This template formats data and writes the output through an output iterator. */ template <typename OutputIt, typename Char> class basic_printf_context { public: /** The character type for the output. */ using char_type = Char; using iterator = OutputIt; using format_arg = basic_format_arg<basic_printf_context>; using parse_context_type = basic_printf_parse_context<Char>; template <typename T> using formatter_type = printf_formatter<T>; private: using format_specs = basic_format_specs<char_type>; OutputIt out_; basic_format_args<basic_printf_context> args_; parse_context_type parse_ctx_; static void parse_flags(format_specs& specs, const Char*& it, const Char* end); // Returns the argument with specified index or, if arg_index is -1, the next // argument. format_arg get_arg(int arg_index = -1); // Parses argument index, flags and width and returns the argument index. int parse_header(const Char*& it, const Char* end, format_specs& specs); public: /** \rst Constructs a ``printf_context`` object. References to the arguments are stored in the context object so make sure they have appropriate lifetimes. \endrst */ basic_printf_context(OutputIt out, basic_string_view<char_type> format_str, basic_format_args<basic_printf_context> args) : out_(out), args_(args), parse_ctx_(format_str) {} OutputIt out() { return out_; } void advance_to(OutputIt it) { out_ = it; } detail::locale_ref locale() { return {}; } format_arg arg(int id) const { return args_.get(id); } parse_context_type& parse_context() { return parse_ctx_; } FMT_CONSTEXPR void on_error(const char* message) { parse_ctx_.on_error(message); } /** Formats stored arguments and writes the output to the range. */ template <typename ArgFormatter = printf_arg_formatter<OutputIt, Char>> OutputIt format(); }; template <typename OutputIt, typename Char> void basic_printf_context<OutputIt, Char>::parse_flags(format_specs& specs, const Char*& it, const Char* end) { for (; it != end; ++it) { switch (*it) { case '-': specs.align = align::left; break; case '+': specs.sign = sign::plus; break; case '0': specs.fill[0] = '0'; break; case ' ': if (specs.sign != sign::plus) { specs.sign = sign::space; } break; case '#': specs.alt = true; break; default: return; } } } template <typename OutputIt, typename Char> typename basic_printf_context<OutputIt, Char>::format_arg basic_printf_context<OutputIt, Char>::get_arg(int arg_index) { if (arg_index < 0) arg_index = parse_ctx_.next_arg_id(); else parse_ctx_.check_arg_id(--arg_index); return detail::get_arg(*this, arg_index); } template <typename OutputIt, typename Char> int basic_printf_context<OutputIt, Char>::parse_header(const Char*& it, const Char* end, format_specs& specs) { int arg_index = -1; char_type c = *it; if (c >= '0' && c <= '9') { // Parse an argument index (if followed by '$') or a width possibly // preceded with '0' flag(s). detail::error_handler eh; int value = parse_nonnegative_int(it, end, eh); if (it != end && *it == '$') { // value is an argument index ++it; arg_index = value; } else { if (c == '0') specs.fill[0] = '0'; if (value != 0) { // Nonzero value means that we parsed width and don't need to // parse it or flags again, so return now. specs.width = value; return arg_index; } } } parse_flags(specs, it, end); // Parse width. if (it != end) { if (*it >= '0' && *it <= '9') { detail::error_handler eh; specs.width = parse_nonnegative_int(it, end, eh); } else if (*it == '*') { ++it; specs.width = static_cast<int>(visit_format_arg( detail::printf_width_handler<char_type>(specs), get_arg())); } } return arg_index; } template <typename OutputIt, typename Char> template <typename ArgFormatter> OutputIt basic_printf_context<OutputIt, Char>::format() { auto out = this->out(); const Char* start = parse_ctx_.begin(); const Char* end = parse_ctx_.end(); auto it = start; while (it != end) { char_type c = *it++; if (c != '%') continue; if (it != end && *it == c) { out = std::copy(start, it, out); start = ++it; continue; } out = std::copy(start, it - 1, out); format_specs specs; specs.align = align::right; // Parse argument index, flags and width. int arg_index = parse_header(it, end, specs); if (arg_index == 0) on_error("argument not found"); // Parse precision. if (it != end && *it == '.') { ++it; c = it != end ? *it : 0; if ('0' <= c && c <= '9') { detail::error_handler eh; specs.precision = parse_nonnegative_int(it, end, eh); } else if (c == '*') { ++it; specs.precision = static_cast<int>( visit_format_arg(detail::printf_precision_handler(), get_arg())); } else { specs.precision = 0; } } format_arg arg = get_arg(arg_index); // For d, i, o, u, x, and X conversion specifiers, if a precision is // specified, the '0' flag is ignored if (specs.precision >= 0 && arg.is_integral()) specs.fill[0] = ' '; // Ignore '0' flag for non-numeric types or if '-' present. if (specs.precision >= 0 && arg.type() == detail::type::cstring_type) { auto str = visit_format_arg(detail::get_cstring<Char>(), arg); auto str_end = str + specs.precision; auto nul = std::find(str, str_end, Char()); arg = detail::make_arg<basic_printf_context>(basic_string_view<Char>( str, detail::to_unsigned(nul != str_end ? nul - str : specs.precision))); } if (specs.alt && visit_format_arg(detail::is_zero_int(), arg)) specs.alt = false; if (specs.fill[0] == '0') { if (arg.is_arithmetic() && specs.align != align::left) specs.align = align::numeric; else specs.fill[0] = ' '; // Ignore '0' flag for non-numeric types or if '-' // flag is also present. } // Parse length and convert the argument to the required type. c = it != end ? *it++ : 0; char_type t = it != end ? *it : 0; using detail::convert_arg; switch (c) { case 'h': if (t == 'h') { ++it; t = it != end ? *it : 0; convert_arg<signed char>(arg, t); } else { convert_arg<short>(arg, t); } break; case 'l': if (t == 'l') { ++it; t = it != end ? *it : 0; convert_arg<long long>(arg, t); } else { convert_arg<long>(arg, t); } break; case 'j': convert_arg<intmax_t>(arg, t); break; case 'z': convert_arg<size_t>(arg, t); break; case 't': convert_arg<std::ptrdiff_t>(arg, t); break; case 'L': // printf produces garbage when 'L' is omitted for long double, no // need to do the same. break; default: --it; convert_arg<void>(arg, c); } // Parse type. if (it == end) FMT_THROW(format_error("invalid format string")); specs.type = static_cast<char>(*it++); if (arg.is_integral()) { // Normalize type. switch (specs.type) { case 'i': case 'u': specs.type = 'd'; break; case 'c': visit_format_arg(detail::char_converter<basic_printf_context>(arg), arg); break; } } start = it; // Format argument. out = visit_format_arg(ArgFormatter(out, specs, *this), arg); } return std::copy(start, it, out); } template <typename Char> using basic_printf_context_t = basic_printf_context<detail::buffer_appender<Char>, Char>; using printf_context = basic_printf_context_t<char>; using wprintf_context = basic_printf_context_t<wchar_t>; using printf_args = basic_format_args<printf_context>; using wprintf_args = basic_format_args<wprintf_context>; /** \rst Constructs an `~fmt::format_arg_store` object that contains references to arguments and can be implicitly converted to `~fmt::printf_args`. \endrst */ template <typename... Args> inline format_arg_store<printf_context, Args...> make_printf_args( const Args&... args) { return {args...}; } /** \rst Constructs an `~fmt::format_arg_store` object that contains references to arguments and can be implicitly converted to `~fmt::wprintf_args`. \endrst */ template <typename... Args> inline format_arg_store<wprintf_context, Args...> make_wprintf_args( const Args&... args) { return {args...}; } template <typename S, typename Char = char_t<S>> inline std::basic_string<Char> vsprintf( const S& format, basic_format_args<basic_printf_context_t<type_identity_t<Char>>> args) { basic_memory_buffer<Char> buffer; vprintf(buffer, to_string_view(format), args); return to_string(buffer); } /** \rst Formats arguments and returns the result as a string. **Example**:: std::string message = fmt::sprintf("The answer is %d", 42); \endrst */ template <typename S, typename... Args, typename Char = enable_if_t<detail::is_string<S>::value, char_t<S>>> inline std::basic_string<Char> sprintf(const S& format, const Args&... args) { using context = basic_printf_context_t<Char>; return vsprintf(to_string_view(format), make_format_args<context>(args...)); } template <typename S, typename Char = char_t<S>> inline int vfprintf( std::FILE* f, const S& format, basic_format_args<basic_printf_context_t<type_identity_t<Char>>> args) { basic_memory_buffer<Char> buffer; vprintf(buffer, to_string_view(format), args); size_t size = buffer.size(); return std::fwrite(buffer.data(), sizeof(Char), size, f) < size ? -1 : static_cast<int>(size); } /** \rst Prints formatted data to the file *f*. **Example**:: fmt::fprintf(stderr, "Don't %s!", "panic"); \endrst */ template <typename S, typename... Args, typename Char = enable_if_t<detail::is_string<S>::value, char_t<S>>> inline int fprintf(std::FILE* f, const S& format, const Args&... args) { using context = basic_printf_context_t<Char>; return vfprintf(f, to_string_view(format), make_format_args<context>(args...)); } template <typename S, typename Char = char_t<S>> inline int vprintf( const S& format, basic_format_args<basic_printf_context_t<type_identity_t<Char>>> args) { return vfprintf(stdout, to_string_view(format), args); } /** \rst Prints formatted data to ``stdout``. **Example**:: fmt::printf("Elapsed time: %.2f seconds", 1.23); \endrst */ template <typename S, typename... Args, FMT_ENABLE_IF(detail::is_string<S>::value)> inline int printf(const S& format_str, const Args&... args) { using context = basic_printf_context_t<char_t<S>>; return vprintf(to_string_view(format_str), make_format_args<context>(args...)); } template <typename S, typename Char = char_t<S>> inline int vfprintf( std::basic_ostream<Char>& os, const S& format, basic_format_args<basic_printf_context_t<type_identity_t<Char>>> args) { basic_memory_buffer<Char> buffer; vprintf(buffer, to_string_view(format), args); detail::write_buffer(os, buffer); return static_cast<int>(buffer.size()); } /** Formats arguments and writes the output to the range. */ template <typename ArgFormatter, typename Char, typename Context = basic_printf_context<typename ArgFormatter::iterator, Char>> typename ArgFormatter::iterator vprintf( detail::buffer<Char>& out, basic_string_view<Char> format_str, basic_format_args<type_identity_t<Context>> args) { typename ArgFormatter::iterator iter(out); Context(iter, format_str, args).template format<ArgFormatter>(); return iter; } /** \rst Prints formatted data to the stream *os*. **Example**:: fmt::fprintf(cerr, "Don't %s!", "panic"); \endrst */ template <typename S, typename... Args, typename Char = char_t<S>> inline int fprintf(std::basic_ostream<Char>& os, const S& format_str, const Args&... args) { using context = basic_printf_context_t<Char>; return vfprintf(os, to_string_view(format_str), make_format_args<context>(args...)); } FMT_END_NAMESPACE #endif // FMT_PRINTF_H_