mirror of
https://github.com/fmtlib/fmt.git
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624 lines
17 KiB
C++
624 lines
17 KiB
C++
/*
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Formatting library for C++
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Copyright (c) 2012 - 2016, Victor Zverovich
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All rights reserved.
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For the license information refer to format.h.
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*/
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#ifndef FMT_PRINTF_H_
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#define FMT_PRINTF_H_
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#include <algorithm> // std::fill_n
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#include <limits> // std::numeric_limits
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#include "fmt/ostream.h"
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namespace fmt {
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namespace internal {
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// Checks if a value fits in int - used to avoid warnings about comparing
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// signed and unsigned integers.
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template <bool IsSigned>
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struct IntChecker {
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template <typename T>
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static bool fits_in_int(T value) {
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unsigned max = std::numeric_limits<int>::max();
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return value <= max;
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}
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static bool fits_in_int(bool) { return true; }
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};
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template <>
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struct IntChecker<true> {
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template <typename T>
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static bool fits_in_int(T value) {
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return value >= std::numeric_limits<int>::min() &&
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value <= std::numeric_limits<int>::max();
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}
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static bool fits_in_int(int) { return true; }
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};
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class PrintfPrecisionHandler {
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public:
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template <typename T>
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typename std::enable_if<std::is_integral<T>::value, int>::type
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operator()(T value) {
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if (!IntChecker<std::numeric_limits<T>::is_signed>::fits_in_int(value))
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FMT_THROW(format_error("number is too big"));
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return static_cast<int>(value);
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}
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template <typename T>
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typename std::enable_if<!std::is_integral<T>::value, int>::type
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operator()(T) {
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FMT_THROW(format_error("precision is not integer"));
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return 0;
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}
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};
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// An argument visitor that returns true iff arg is a zero integer.
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class IsZeroInt {
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public:
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template <typename T>
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typename std::enable_if<std::is_integral<T>::value, bool>::type
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operator()(T value) { return value == 0; }
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template <typename T>
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typename std::enable_if<!std::is_integral<T>::value, bool>::type
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operator()(T) { return false; }
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};
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template <typename T>
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struct make_unsigned_or_bool : std::make_unsigned<T> {};
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template <>
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struct make_unsigned_or_bool<bool> {
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using type = bool;
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};
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template <typename T, typename Context>
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class ArgConverter {
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private:
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typedef typename Context::char_type Char;
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basic_arg<Context> &arg_;
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typename Context::char_type type_;
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public:
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ArgConverter(basic_arg<Context> &arg, Char type)
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: arg_(arg), type_(type) {}
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void operator()(bool value) {
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if (type_ != 's')
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operator()<bool>(value);
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}
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template <typename U>
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typename std::enable_if<std::is_integral<U>::value>::type
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operator()(U value) {
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bool is_signed = type_ == 'd' || type_ == 'i';
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typedef typename std::conditional<
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std::is_same<T, void>::value, U, T>::type TargetType;
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if (sizeof(TargetType) <= sizeof(int)) {
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// Extra casts are used to silence warnings.
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if (is_signed) {
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arg_ = internal::make_arg<Context>(
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static_cast<int>(static_cast<TargetType>(value)));
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} else {
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typedef typename make_unsigned_or_bool<TargetType>::type Unsigned;
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arg_ = internal::make_arg<Context>(
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static_cast<unsigned>(static_cast<Unsigned>(value)));
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}
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} else {
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if (is_signed) {
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// glibc's printf doesn't sign extend arguments of smaller types:
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// std::printf("%lld", -42); // prints "4294967254"
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// but we don't have to do the same because it's a UB.
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arg_ = internal::make_arg<Context>(static_cast<long long>(value));
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} else {
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arg_ = internal::make_arg<Context>(
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static_cast<typename make_unsigned_or_bool<U>::type>(value));
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}
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}
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}
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template <typename U>
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typename std::enable_if<!std::is_integral<U>::value>::type operator()(U) {
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// No coversion needed for non-integral types.
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}
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};
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// Converts an integer argument to T for printf, if T is an integral type.
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// If T is void, the argument is converted to corresponding signed or unsigned
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// type depending on the type specifier: 'd' and 'i' - signed, other -
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// unsigned).
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template <typename T, typename Context, typename Char>
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void convert_arg(basic_arg<Context> &arg, Char type) {
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visit(ArgConverter<T, Context>(arg, type), arg);
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}
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// Converts an integer argument to char for printf.
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template <typename Context>
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class CharConverter {
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private:
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basic_arg<Context> &arg_;
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FMT_DISALLOW_COPY_AND_ASSIGN(CharConverter);
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public:
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explicit CharConverter(basic_arg<Context> &arg) : arg_(arg) {}
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template <typename T>
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typename std::enable_if<std::is_integral<T>::value>::type
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operator()(T value) {
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arg_ = internal::make_arg<Context>(static_cast<char>(value));
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}
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template <typename T>
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typename std::enable_if<!std::is_integral<T>::value>::type operator()(T) {
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// No coversion needed for non-integral types.
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}
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};
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// Checks if an argument is a valid printf width specifier and sets
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// left alignment if it is negative.
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template <typename Char>
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class PrintfWidthHandler {
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private:
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typedef basic_format_specs<Char> format_specs;
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format_specs &spec_;
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FMT_DISALLOW_COPY_AND_ASSIGN(PrintfWidthHandler);
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public:
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explicit PrintfWidthHandler(format_specs &spec) : spec_(spec) {}
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template <typename T>
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typename std::enable_if<std::is_integral<T>::value, unsigned>::type
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operator()(T value) {
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typedef typename internal::int_traits<T>::main_type UnsignedType;
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UnsignedType width = static_cast<UnsignedType>(value);
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if (internal::is_negative(value)) {
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spec_.align_ = ALIGN_LEFT;
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width = 0 - width;
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}
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unsigned int_max = std::numeric_limits<int>::max();
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if (width > int_max)
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FMT_THROW(format_error("number is too big"));
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return static_cast<unsigned>(width);
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}
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template <typename T>
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typename std::enable_if<!std::is_integral<T>::value, unsigned>::type
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operator()(T) {
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FMT_THROW(format_error("width is not integer"));
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return 0;
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}
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};
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} // namespace internal
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/**
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\rst
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The ``printf`` argument formatter.
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\endrst
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*/
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template <typename Char>
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class printf_arg_formatter : public internal::arg_formatter_base<Char> {
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private:
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void write_null_pointer() {
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this->spec().type_ = 0;
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this->write("(nil)");
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}
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typedef internal::arg_formatter_base<Char> Base;
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public:
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typedef typename Base::format_specs format_specs;
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/**
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\rst
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Constructs an argument formatter object.
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*buffer* is a reference to the output buffer and *spec* contains format
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specifier information for standard argument types.
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\endrst
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*/
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printf_arg_formatter(basic_buffer<Char> &buffer, format_specs &spec)
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: internal::arg_formatter_base<Char>(buffer, spec) {}
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using Base::operator();
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/** Formats an argument of type ``bool``. */
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void operator()(bool value) {
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format_specs &fmt_spec = this->spec();
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if (fmt_spec.type_ != 's')
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return (*this)(value ? 1 : 0);
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fmt_spec.type_ = 0;
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this->write(value);
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}
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/** Formats a character. */
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void operator()(Char value) {
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format_specs &fmt_spec = this->spec();
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if (fmt_spec.type_ && fmt_spec.type_ != 'c')
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return (*this)(static_cast<int>(value));
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fmt_spec.flags_ = 0;
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fmt_spec.align_ = ALIGN_RIGHT;
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Base::operator()(value);
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}
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/** Formats a null-terminated C string. */
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void operator()(const char *value) {
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if (value)
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Base::operator()(value);
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else if (this->spec().type_ == 'p')
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write_null_pointer();
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else
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this->write("(null)");
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}
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/** Formats a pointer. */
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void operator()(const void *value) {
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if (value)
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return Base::operator()(value);
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this->spec().type_ = 0;
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write_null_pointer();
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}
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/** Formats an argument of a custom (user-defined) type. */
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void operator()(internal::custom_value<Char> c) {
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const Char format_str[] = {'}', '\0'};
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auto args = basic_args<basic_context<Char>>();
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basic_context<Char> ctx(basic_string_view<Char>(format_str), args);
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c.format(this->writer().buffer(), c.value, &ctx);
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}
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};
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template <typename Char,
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typename ArgFormatter = printf_arg_formatter<Char> >
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class printf_context;
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template <typename T, typename Char = char>
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struct printf_formatter {
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template <typename ParseContext>
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const Char *parse(ParseContext& ctx) { return ctx.begin(); }
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void format(basic_buffer<Char> &buf, const T &value, printf_context<Char> &) {
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internal::format_value(buf, value);
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}
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};
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/** This template formats data and writes the output to a writer. */
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template <typename Char, typename ArgFormatter>
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class printf_context :
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private internal::context_base<
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Char, printf_context<Char, ArgFormatter>> {
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public:
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/** The character type for the output. */
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using char_type = Char;
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template <typename T>
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using formatter_type = printf_formatter<T>;
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private:
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typedef internal::context_base<Char, printf_context> Base;
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typedef typename Base::format_arg format_arg;
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typedef basic_format_specs<Char> format_specs;
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typedef internal::null_terminating_iterator<Char> iterator;
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void parse_flags(format_specs &spec, iterator &it);
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// Returns the argument with specified index or, if arg_index is equal
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// to the maximum unsigned value, the next argument.
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format_arg get_arg(
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iterator it,
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unsigned arg_index = (std::numeric_limits<unsigned>::max)());
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// Parses argument index, flags and width and returns the argument index.
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unsigned parse_header(iterator &it, format_specs &spec);
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public:
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/**
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\rst
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Constructs a ``printf_context`` object. References to the arguments and
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the writer are stored in the context object so make sure they have
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appropriate lifetimes.
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\endrst
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*/
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printf_context(
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basic_string_view<Char> format_str, basic_args<printf_context> args)
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: Base(format_str, args) {}
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using Base::get_parse_context;
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/** Formats stored arguments and writes the output to the buffer. */
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FMT_API void format(basic_buffer<Char> &buffer);
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};
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template <typename Char, typename AF>
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void printf_context<Char, AF>::parse_flags(format_specs &spec, iterator &it) {
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for (;;) {
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switch (*it++) {
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case '-':
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spec.align_ = ALIGN_LEFT;
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break;
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case '+':
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spec.flags_ |= SIGN_FLAG | PLUS_FLAG;
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break;
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case '0':
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spec.fill_ = '0';
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break;
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case ' ':
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spec.flags_ |= SIGN_FLAG;
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break;
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case '#':
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spec.flags_ |= HASH_FLAG;
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break;
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default:
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--it;
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return;
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}
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}
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}
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template <typename Char, typename AF>
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typename printf_context<Char, AF>::format_arg printf_context<Char, AF>::get_arg(
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iterator it, unsigned arg_index) {
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(void)it;
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const char *error = 0;
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format_arg arg;
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if (arg_index == std::numeric_limits<unsigned>::max()) {
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arg_index = this->next_arg_index(error);
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if (!error)
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arg = this->do_get_arg(arg_index, error);
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} else {
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arg = Base::get_arg(arg_index - 1, error);
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}
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if (error)
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FMT_THROW(format_error(!*it ? "invalid format string" : error));
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return arg;
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}
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template <typename Char, typename AF>
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unsigned printf_context<Char, AF>::parse_header(
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iterator &it, format_specs &spec) {
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unsigned arg_index = std::numeric_limits<unsigned>::max();
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Char c = *it;
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if (c >= '0' && c <= '9') {
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// Parse an argument index (if followed by '$') or a width possibly
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// preceded with '0' flag(s).
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internal::error_handler eh;
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unsigned value = parse_nonnegative_int(it, eh);
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if (*it == '$') { // value is an argument index
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++it;
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arg_index = value;
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} else {
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if (c == '0')
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spec.fill_ = '0';
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if (value != 0) {
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// Nonzero value means that we parsed width and don't need to
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// parse it or flags again, so return now.
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spec.width_ = value;
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return arg_index;
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}
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}
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}
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parse_flags(spec, it);
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// Parse width.
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if (*it >= '0' && *it <= '9') {
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internal::error_handler eh;
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spec.width_ = parse_nonnegative_int(it, eh);
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} else if (*it == '*') {
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++it;
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spec.width_ = visit(internal::PrintfWidthHandler<Char>(spec), get_arg(it));
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}
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return arg_index;
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}
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template <typename Char, typename AF>
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void printf_context<Char, AF>::format(basic_buffer<Char> &buffer) {
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Base &base = *this;
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auto start = iterator(base);
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auto it = start;
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using internal::pointer_from;
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while (*it) {
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Char c = *it++;
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if (c != '%') continue;
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if (*it == c) {
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buffer.append(pointer_from(start), pointer_from(it));
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start = ++it;
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continue;
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}
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buffer.append(pointer_from(start), pointer_from(it) - 1);
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format_specs spec;
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spec.align_ = ALIGN_RIGHT;
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// Parse argument index, flags and width.
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unsigned arg_index = parse_header(it, spec);
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// Parse precision.
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if (*it == '.') {
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++it;
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if ('0' <= *it && *it <= '9') {
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internal::error_handler eh;
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spec.precision_ = static_cast<int>(parse_nonnegative_int(it, eh));
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} else if (*it == '*') {
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++it;
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spec.precision_ =
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visit(internal::PrintfPrecisionHandler(), get_arg(it));
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}
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}
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format_arg arg = get_arg(it, arg_index);
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if (spec.flag(HASH_FLAG) && visit(internal::IsZeroInt(), arg))
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spec.flags_ &= ~internal::to_unsigned<int>(HASH_FLAG);
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if (spec.fill_ == '0') {
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if (arg.is_numeric())
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spec.align_ = ALIGN_NUMERIC;
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else
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spec.fill_ = ' '; // Ignore '0' flag for non-numeric types.
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}
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// Parse length and convert the argument to the required type.
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using internal::convert_arg;
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switch (*it++) {
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case 'h':
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if (*it == 'h')
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convert_arg<signed char>(arg, *++it);
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else
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convert_arg<short>(arg, *it);
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break;
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case 'l':
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if (*it == 'l')
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convert_arg<long long>(arg, *++it);
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else
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convert_arg<long>(arg, *it);
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break;
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case 'j':
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convert_arg<intmax_t>(arg, *it);
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break;
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case 'z':
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convert_arg<std::size_t>(arg, *it);
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break;
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case 't':
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convert_arg<std::ptrdiff_t>(arg, *it);
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break;
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case 'L':
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// printf produces garbage when 'L' is omitted for long double, no
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// need to do the same.
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break;
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default:
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--it;
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convert_arg<void>(arg, *it);
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}
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// Parse type.
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if (!*it)
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FMT_THROW(format_error("invalid format string"));
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spec.type_ = static_cast<char>(*it++);
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if (arg.is_integral()) {
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// Normalize type.
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switch (spec.type_) {
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case 'i': case 'u':
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spec.type_ = 'd';
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break;
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case 'c':
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// TODO: handle wchar_t
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visit(internal::CharConverter<printf_context<Char, AF>>(arg), arg);
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break;
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}
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}
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start = it;
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// Format argument.
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visit(AF(buffer, spec), arg);
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}
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buffer.append(pointer_from(start), pointer_from(it));
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}
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template <typename Char>
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void printf(basic_buffer<Char> &buf, basic_string_view<Char> format,
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basic_args<printf_context<Char>> args) {
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printf_context<Char>(format, args).format(buf);
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}
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typedef basic_args<printf_context<char>> printf_args;
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inline std::string vsprintf(string_view format, printf_args args) {
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memory_buffer buffer;
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printf(buffer, format, args);
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return to_string(buffer);
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}
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/**
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\rst
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Formats arguments and returns the result as a string.
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**Example**::
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|
|
|
std::string message = fmt::sprintf("The answer is %d", 42);
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|
\endrst
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|
*/
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|
template <typename... Args>
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|
inline std::string sprintf(string_view format_str, const Args & ... args) {
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|
return vsprintf(format_str, make_args<printf_context<char>>(args...));
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|
}
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|
|
|
inline std::wstring vsprintf(
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|
wstring_view format, basic_args<printf_context<wchar_t>> args) {
|
|
wmemory_buffer buffer;
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|
printf(buffer, format, args);
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|
return to_string(buffer);
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|
}
|
|
|
|
template <typename... Args>
|
|
inline std::wstring sprintf(wstring_view format_str, const Args & ... args) {
|
|
auto vargs = make_args<printf_context<wchar_t>>(args...);
|
|
return vsprintf(format_str, vargs);
|
|
}
|
|
|
|
FMT_API int vfprintf(std::FILE *f, string_view format, printf_args args);
|
|
|
|
/**
|
|
\rst
|
|
Prints formatted data to the file *f*.
|
|
|
|
**Example**::
|
|
|
|
fmt::fprintf(stderr, "Don't %s!", "panic");
|
|
\endrst
|
|
*/
|
|
template <typename... Args>
|
|
inline int fprintf(std::FILE *f, string_view format_str, const Args & ... args) {
|
|
auto vargs = make_args<printf_context<char>>(args...);
|
|
return vfprintf(f, format_str, vargs);
|
|
}
|
|
|
|
inline int vprintf(string_view format, printf_args args) {
|
|
return vfprintf(stdout, format, args);
|
|
}
|
|
|
|
/**
|
|
\rst
|
|
Prints formatted data to ``stdout``.
|
|
|
|
**Example**::
|
|
|
|
fmt::printf("Elapsed time: %.2f seconds", 1.23);
|
|
\endrst
|
|
*/
|
|
template <typename... Args>
|
|
inline int printf(string_view format_str, const Args & ... args) {
|
|
return vprintf(format_str, make_args<printf_context<char>>(args...));
|
|
}
|
|
|
|
inline int vfprintf(std::ostream &os, string_view format_str, printf_args args) {
|
|
memory_buffer buffer;
|
|
printf(buffer, format_str, args);
|
|
internal::write(os, buffer);
|
|
return static_cast<int>(buffer.size());
|
|
}
|
|
|
|
/**
|
|
\rst
|
|
Prints formatted data to the stream *os*.
|
|
|
|
**Example**::
|
|
|
|
fprintf(cerr, "Don't %s!", "panic");
|
|
\endrst
|
|
*/
|
|
template <typename... Args>
|
|
inline int fprintf(std::ostream &os, string_view format_str,
|
|
const Args & ... args) {
|
|
auto vargs = make_args<printf_context<char>>(args...);
|
|
return vfprintf(os, format_str, vargs);
|
|
}
|
|
} // namespace fmt
|
|
|
|
#endif // FMT_PRINTF_H_
|