format.cpp

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/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          http://www.mrpt.org/                          |
   |                                                                        |
   | Copyright (c) 2005-2018, Individual contributors, see AUTHORS file     |
   | See: http://www.mrpt.org/Authors - All rights reserved.                |
   | Released under BSD License. See details in http://www.mrpt.org/License |
   +------------------------------------------------------------------------+ */
 
#include "core-precomp.h"  // Precompiled headers
 
#include <mrpt/core/format.h>
#include <cstdarg>
 
// A sprintf-like function for std::string
std::string mrpt::format(const char* fmt, ...)
{
        if (!fmt) return std::string();
 
        int result = -1, length = 2048;
        std::string buffer;
        while (result == -1)
        {
                buffer.resize(length);
 
                va_list args;  // This must be done WITHIN the loop
                va_start(args, fmt);
#if defined(_MSC_VER)
                result = ::vsnprintf_s(&buffer[0], length, _TRUNCATE, fmt, args);
#else
                result = ::vsnprintf(&buffer[0], length, fmt, args);
#endif
                va_end(args);
 
                // Truncated?
                if (result >= length) result = -1;
                length *= 2;
 
                // Ok?
                if (result >= 0)
                {
                        buffer.resize(result);
                }
        }
        return buffer;
}