format.cpp

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/* +---------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)               |
   |                          http://www.mrpt.org/                             |
   |                                                                           |
   | Copyright (c) 2005-2017, 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 "base-precomp.h"  // Precompiled headers


#include <mrpt/utils/utils_defs.h>
#include <mrpt/system/os.h>
#include <mrpt/system/memory.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);
                result = mrpt::system::os::vsnprintf(&buffer[0], length, fmt, args);
                va_end(args);

                // Truncated?
                if (result>=length) result=-1;
                length*=2;

                // Ok?
                if (result >= 0) {
                        buffer.resize(result);
                }
        }

        return buffer;
}