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C++

// 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 "format.h"
FMT_BEGIN_NAMESPACE
FMT_MODULE_EXPORT_BEGIN
template <typename T> struct printf_formatter { printf_formatter() = delete; };
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 {
private:
OutputIt out_;
basic_format_args<basic_printf_context> args_;
public:
using char_type = Char;
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>;
/**
\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_format_args<basic_printf_context> args)
: out_(out), args_(args) {}
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); }
FMT_CONSTEXPR void on_error(const char* message) {
detail::error_handler().on_error(message);
}
};
FMT_BEGIN_DETAIL_NAMESPACE
// 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;
}
};
// The ``printf`` argument formatter.
template <typename OutputIt, typename Char>
class printf_arg_formatter : public arg_formatter<Char> {
private:
using base = arg_formatter<Char>;
using context_type = basic_printf_context<OutputIt, Char>;
using format_specs = basic_format_specs<Char>;
context_type& context_;
OutputIt write_null_pointer(bool is_string = false) {
auto s = this->specs;
s.type = presentation_type::none;
return write_bytes(this->out, is_string ? "(null)" : "(nil)", s);
}
public:
printf_arg_formatter(OutputIt iter, format_specs& s, context_type& ctx)
: base{iter, s, locale_ref()}, context_(ctx) {}
OutputIt operator()(monostate value) { return base::operator()(value); }
template <typename T, FMT_ENABLE_IF(detail::is_integral<T>::value)>
OutputIt operator()(T value) {
// MSVC2013 fails to compile separate overloads for bool and Char so use
// std::is_same instead.
if (std::is_same<T, Char>::value) {
format_specs fmt_specs = this->specs;
if (fmt_specs.type != presentation_type::none &&
fmt_specs.type != presentation_type::chr) {
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 write<Char>(this->out, static_cast<Char>(value), fmt_specs);
}
return base::operator()(value);
}
template <typename T, FMT_ENABLE_IF(std::is_floating_point<T>::value)>
OutputIt operator()(T value) {
return base::operator()(value);
}
/** Formats a null-terminated C string. */
OutputIt operator()(const char* value) {
if (value) return base::operator()(value);
return write_null_pointer(this->specs.type != presentation_type::pointer);
}
/** Formats a null-terminated wide C string. */
OutputIt operator()(const wchar_t* value) {
if (value) return base::operator()(value);
return write_null_pointer(this->specs.type != presentation_type::pointer);
}
OutputIt operator()(basic_string_view<Char> value) {
return base::operator()(value);
}
/** Formats a pointer. */
OutputIt operator()(const void* value) {
return value ? base::operator()(value) : write_null_pointer();
}
/** Formats an argument of a custom (user-defined) type. */
OutputIt operator()(typename basic_format_arg<context_type>::handle handle) {
auto parse_ctx =
basic_printf_parse_context<Char>(basic_string_view<Char>());
handle.format(parse_ctx, context_);
return this->out;
}
};
template <typename Char>
void parse_flags(basic_format_specs<Char>& 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 Char, typename GetArg>
int parse_header(const Char*& it, const Char* end,
basic_format_specs<Char>& specs, GetArg get_arg) {
int arg_index = -1;
Char c = *it;
if (c >= '0' && c <= '9') {
// Parse an argument index (if followed by '$') or a width possibly
// preceded with '0' flag(s).
int value = parse_nonnegative_int(it, end, -1);
if (it != end && *it == '$') { // value is an argument index
++it;
arg_index = value != -1 ? value : max_value<int>();
} 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.
if (value == -1) FMT_THROW(format_error("number is too big"));
specs.width = value;
return arg_index;
}
}
}
parse_flags(specs, it, end);
// Parse width.
if (it != end) {
if (*it >= '0' && *it <= '9') {
specs.width = parse_nonnegative_int(it, end, -1);
if (specs.width == -1) FMT_THROW(format_error("number is too big"));
} else if (*it == '*') {
++it;
specs.width = static_cast<int>(visit_format_arg(
detail::printf_width_handler<Char>(specs), get_arg(-1)));
}
}
return arg_index;
}
template <typename Char, typename Context>
void vprintf(buffer<Char>& buf, basic_string_view<Char> format,
basic_format_args<Context> args) {
using OutputIt = buffer_appender<Char>;
auto out = OutputIt(buf);
auto context = basic_printf_context<OutputIt, Char>(out, args);
auto parse_ctx = basic_printf_parse_context<Char>(format);
// Returns the argument with specified index or, if arg_index is -1, the next
// argument.
auto 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(context, arg_index);
};
const Char* start = parse_ctx.begin();
const Char* end = parse_ctx.end();
auto it = start;
while (it != end) {
if (!detail::find<false, Char>(it, end, '%', it)) {
it = end; // detail::find leaves it == nullptr if it doesn't find '%'
break;
}
Char c = *it++;
if (it != end && *it == c) {
out = detail::write(
out, basic_string_view<Char>(start, detail::to_unsigned(it - start)));
start = ++it;
continue;
}
out = detail::write(out, basic_string_view<Char>(
start, detail::to_unsigned(it - 1 - start)));
basic_format_specs<Char> specs;
specs.align = align::right;
// Parse argument index, flags and width.
int arg_index = parse_header(it, end, specs, get_arg);
if (arg_index == 0) parse_ctx.on_error("argument not found");
// Parse precision.
if (it != end && *it == '.') {
++it;
c = it != end ? *it : 0;
if ('0' <= c && c <= '9') {
specs.precision = parse_nonnegative_int(it, end, 0);
} else if (c == '*') {
++it;
specs.precision = static_cast<int>(
visit_format_arg(detail::printf_precision_handler(), get_arg(-1)));
} else {
specs.precision = 0;
}
}
auto 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<OutputIt, Char>>(
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 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"));
char type = static_cast<char>(*it++);
if (arg.is_integral()) {
// Normalize type.
switch (type) {
case 'i':
case 'u':
type = 'd';
break;
case 'c':
visit_format_arg(
detail::char_converter<basic_printf_context<OutputIt, Char>>(arg),
arg);
break;
}
}
specs.type = parse_presentation_type(type);
if (specs.type == presentation_type::none)
parse_ctx.on_error("invalid type specifier");
start = it;
// Format argument.
out = visit_format_arg(
detail::printf_arg_formatter<OutputIt, Char>(out, specs, context), arg);
}
detail::write(out, basic_string_view<Char>(start, to_unsigned(it - start)));
}
FMT_END_DETAIL_NAMESPACE
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... T>
inline auto make_printf_args(const T&... args)
-> format_arg_store<printf_context, T...> {
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... T>
inline auto make_wprintf_args(const T&... args)
-> format_arg_store<wprintf_context, T...> {
return {args...};
}
template <typename S, typename Char = char_t<S>>
inline auto vsprintf(
const S& fmt,
basic_format_args<basic_printf_context_t<type_identity_t<Char>>> args)
-> std::basic_string<Char> {
basic_memory_buffer<Char> buffer;
vprintf(buffer, detail::to_string_view(fmt), 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... T,
typename Char = enable_if_t<detail::is_string<S>::value, char_t<S>>>
inline auto sprintf(const S& fmt, const T&... args) -> std::basic_string<Char> {
using context = basic_printf_context_t<Char>;
return vsprintf(detail::to_string_view(fmt),
fmt::make_format_args<context>(args...));
}
template <typename S, typename Char = char_t<S>>
inline auto vfprintf(
std::FILE* f, const S& fmt,
basic_format_args<basic_printf_context_t<type_identity_t<Char>>> args)
-> int {
basic_memory_buffer<Char> buffer;
vprintf(buffer, detail::to_string_view(fmt), 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... T, typename Char = char_t<S>>
inline auto fprintf(std::FILE* f, const S& fmt, const T&... args) -> int {
using context = basic_printf_context_t<Char>;
return vfprintf(f, detail::to_string_view(fmt),
fmt::make_format_args<context>(args...));
}
template <typename S, typename Char = char_t<S>>
inline auto vprintf(
const S& fmt,
basic_format_args<basic_printf_context_t<type_identity_t<Char>>> args)
-> int {
return vfprintf(stdout, detail::to_string_view(fmt), args);
}
/**
\rst
Prints formatted data to ``stdout``.
**Example**::
fmt::printf("Elapsed time: %.2f seconds", 1.23);
\endrst
*/
template <typename S, typename... T, FMT_ENABLE_IF(detail::is_string<S>::value)>
inline auto printf(const S& fmt, const T&... args) -> int {
return vprintf(
detail::to_string_view(fmt),
fmt::make_format_args<basic_printf_context_t<char_t<S>>>(args...));
}
FMT_MODULE_EXPORT_END
FMT_END_NAMESPACE
#endif // FMT_PRINTF_H_