printf.h

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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 "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>;
 
    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);
    }
 
    OutputIt operator()(const char* value)
    {
        if (value)
            return base::operator()(value);
        return write_null_pointer(this->specs.type != presentation_type::pointer);
    }
 
    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);
    }
 
    OutputIt operator()(const void* value)
    {
        return value ? base::operator()(value) : write_null_pointer();
    }
 
    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>;
 
template <typename... T>
inline auto make_printf_args(const T&... args)
    -> format_arg_store<printf_context, T...>
{
    return {args...};
}
 
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);
}
 
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);
}
 
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);
}
 
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_