spdlog/src/fmt.cpp

#ifndef SPDLOG_COMPILED_LIB
#error Please define SPDLOG_COMPILED_LIB to compile this file.
#endif

// Slightly modified version of fmt lib's format.cc source file.
// Copyright (c) 2012 - 2016, Victor Zverovich
// All rights reserved.

#if !defined(SPDLOG_FMT_EXTERNAL)
#include "spdlog/fmt/bundled/format-inl.h"

FMT_BEGIN_NAMESPACE
namespace internal {

template<typename T>
int format_float(char *buf, std::size_t size, const char *format, int precision, T value)
{
#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
    if (precision > 100000)
        throw std::runtime_error("fuzz mode - avoid large allocation inside snprintf");
#endif
    // Suppress the warning about nonliteral format string.
    auto snprintf_ptr = FMT_SNPRINTF;
    return precision < 0 ? snprintf_ptr(buf, size, format, value) : snprintf_ptr(buf, size, format, precision, value);
}
struct sprintf_specs
{
    int precision;
    char type;
    bool alt : 1;

    template<typename Char>
    constexpr sprintf_specs(basic_format_specs<Char> specs)
        : precision(specs.precision)
        , type(specs.type)
        , alt(specs.alt)
    {}

    constexpr bool has_precision() const
    {
        return precision >= 0;
    }
};

// This is deprecated and is kept only to preserve ABI compatibility.
template<typename Double>
char *sprintf_format(Double value, internal::buffer<char> &buf, sprintf_specs specs)
{
    // Buffer capacity must be non-zero, otherwise MSVC's vsnprintf_s will fail.
    FMT_ASSERT(buf.capacity() != 0, "empty buffer");

    // Build format string.
    enum
    {
        max_format_size = 10
    }; // longest format: %#-*.*Lg
    char format[max_format_size];
    char *format_ptr = format;
    *format_ptr++ = '%';
    if (specs.alt || !specs.type)
        *format_ptr++ = '#';
    if (specs.precision >= 0)
    {
        *format_ptr++ = '.';
        *format_ptr++ = '*';
    }
    if (std::is_same<Double, long double>::value)
        *format_ptr++ = 'L';

    char type = specs.type;

    if (type == '%')
        type = 'f';
    else if (type == 0 || type == 'n')
        type = 'g';
#if FMT_MSC_VER
    if (type == 'F')
    {
        // MSVC's printf doesn't support 'F'.
        type = 'f';
    }
#endif
    *format_ptr++ = type;
    *format_ptr = '\0';

    // Format using snprintf.
    char *start = nullptr;
    char *decimal_point_pos = nullptr;
    for (;;)
    {
        std::size_t buffer_size = buf.capacity();
        start = &buf[0];
        int result = format_float(start, buffer_size, format, specs.precision, value);
        if (result >= 0)
        {
            unsigned n = internal::to_unsigned(result);
            if (n < buf.capacity())
            {
                // Find the decimal point.
                auto p = buf.data(), end = p + n;
                if (*p == '+' || *p == '-')
                    ++p;
                if (specs.type != 'a' && specs.type != 'A')
                {
                    while (p < end && *p >= '0' && *p <= '9')
                        ++p;
                    if (p < end && *p != 'e' && *p != 'E')
                    {
                        decimal_point_pos = p;
                        if (!specs.type)
                        {
                            // Keep only one trailing zero after the decimal point.
                            ++p;
                            if (*p == '0')
                                ++p;
                            while (p != end && *p >= '1' && *p <= '9')
                                ++p;
                            char *where = p;
                            while (p != end && *p == '0')
                                ++p;
                            if (p == end || *p < '0' || *p > '9')
                            {
                                if (p != end)
                                    std::memmove(where, p, to_unsigned(end - p));
                                n -= static_cast<unsigned>(p - where);
                            }
                        }
                    }
                }
                buf.resize(n);
                break; // The buffer is large enough - continue with formatting.
            }
            buf.reserve(n + 1);
        }
        else
        {
            // If result is negative we ask to increase the capacity by at least 1,
            // but as std::vector, the buffer grows exponentially.
            buf.reserve(buf.capacity() + 1);
        }
    }
    return decimal_point_pos;
}
} // namespace internal

template FMT_API char *internal::sprintf_format(double, internal::buffer<char> &, sprintf_specs);
template FMT_API char *internal::sprintf_format(long double, internal::buffer<char> &, sprintf_specs);

template struct FMT_API internal::basic_data<void>;

// Workaround a bug in MSVC2013 that prevents instantiation of format_float.
int (*instantiate_format_float)(double, int, internal::float_specs, internal::buffer<char> &) = internal::format_float;

#ifndef FMT_STATIC_THOUSANDS_SEPARATOR
template FMT_API internal::locale_ref::locale_ref(const std::locale &loc);
template FMT_API std::locale internal::locale_ref::get<std::locale>() const;
#endif

// Explicit instantiations for char.

template FMT_API std::string internal::grouping_impl<char>(locale_ref);
template FMT_API char internal::thousands_sep_impl(locale_ref);
template FMT_API char internal::decimal_point_impl(locale_ref);

template FMT_API void internal::buffer<char>::append(const char *, const char *);

template FMT_API void internal::arg_map<format_context>::init(const basic_format_args<format_context> &args);

template FMT_API std::string internal::vformat<char>(string_view, basic_format_args<format_context>);

template FMT_API format_context::iterator internal::vformat_to(internal::buffer<char> &, string_view, basic_format_args<format_context>);

template FMT_API int internal::snprintf_float(double, int, internal::float_specs, internal::buffer<char> &);
template FMT_API int internal::snprintf_float(long double, int, internal::float_specs, internal::buffer<char> &);
template FMT_API int internal::format_float(double, int, internal::float_specs, internal::buffer<char> &);
template FMT_API int internal::format_float(long double, int, internal::float_specs, internal::buffer<char> &);

// Explicit instantiations for wchar_t.

template FMT_API std::string internal::grouping_impl<wchar_t>(locale_ref);
template FMT_API wchar_t internal::thousands_sep_impl(locale_ref);
template FMT_API wchar_t internal::decimal_point_impl(locale_ref);

template FMT_API void internal::buffer<wchar_t>::append(const wchar_t *, const wchar_t *);

template FMT_API std::wstring internal::vformat<wchar_t>(wstring_view, basic_format_args<wformat_context>);
FMT_END_NAMESPACE

#endif