format.hpp

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#pragma once
#ifndef _LOGIT_FORMAT_HPP_INCLUDED
#define _LOGIT_FORMAT_HPP_INCLUDED

 
#include <cstdarg>
#include <vector>
#include <string>
 
#ifdef LOGIT_USE_FMT_LIB
#include <fmt/core.h>
#endif
 
namespace logit {

    inline std::string format(const char *fmt, ...) {
#       ifdef LOGIT_USE_FMT_LIB
        va_list args;
        va_start(args, fmt);
        std::string result = fmt::vformat(fmt, fmt::make_format_args(args));
        va_end(args);
        return result;
#       else
        va_list args;
        va_start(args, fmt);
        std::vector<char> buffer(1024);
        for (;;) {
            va_list args_copy;
            va_copy(args_copy, args); // Copy args to prevent modifying the original list.
            int res = vsnprintf(buffer.data(), buffer.size(), fmt, args_copy);
            va_end(args_copy); // Clean up the copied argument list.
 
            if ((res >= 0) && (res < static_cast<int>(buffer.size()))) {
                va_end(args); // Clean up the original argument list.
                return std::string(buffer.data()); // Return the formatted string.
            }
 
            // If the buffer was too small, resize it.
            const size_t size = res < 0 ? buffer.size() * 2 : static_cast<size_t>(res) + 1;
            buffer.clear();
            buffer.resize(size);
        }
#       endif
    }
 
}; // namespace logit
 
#endif // _LOGIT_FORMAT_HPP_INCLUDED