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// 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_