FileIOHelpers.h

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// This file is part of the MercuryDPM project (https://www.mercurydpm.org).
// Copyright (c), The MercuryDPM Developers Team. All rights reserved.
// License: BSD 3-Clause License; see the LICENSE file in the root directory.
 
#ifndef MERCURYDPM_FILEIO_HELPERS_H
#define MERCURYDPM_FILEIO_HELPERS_H
 
#include "Logger.h"
#include "Math/ExtendedMath.h"
 
#include <fstream>
#include <string>
#include <vector>
 
namespace helpers
{
    bool writeToFile(const std::string & filename, const std::string & filecontent);
 
    void writeCommandLineToFile(const std::string & filename, const int argc, char * const argv[]);
 
    bool addToFile(const std::string & filename, const std::string & filecontent);
 
    bool fileExists(const std::string & strFilename);
 
    bool openFile(std::fstream& file, const std::string & filename, std::fstream::openmode mode);
 
    std::vector<double> readArrayFromFile(const std::string & filename, int& n, int& m);
 
    void more(const std::string & filename, unsigned nLines = constants::unsignedMax);
 
    bool createDirectory(const std::string & directory, bool allowExists = false);
 
    std::string getPath();
 
    template<typename T>
    bool readOptionalVariable(std::istream& is, const std::string& name, T& variable)
    {
        const auto pos = is.tellg();
        std::string dummy;
        is >> dummy;
        if (dummy == name)
        {
            is >> variable;
            return true;
        } else {
            is.seekg(pos);
            return false;
        }
    }
 
    template<typename T>
    T readFromFile(const std::string & fileName, const std::string & varName, const T defaultValue)
    {
        //open filestream
        std::ifstream is(fileName.c_str(), std::ios::in);
        if (is.fail())
        {
            logger(INFO, "readFromFile: file % could not be opened, variable % set to default value %",
                fileName, varName, defaultValue);
            return defaultValue;
        }
        
        //read in variables, until the right one is fount
        std::string s;
        while (!is.eof())
        {
            is >> s;
            if (s == varName)
            {
                T value;
                is >> value;
                logger(INFO, "readFromFile: variable % set to % ", varName, value);
                return value;
            }
        }
        
        //if the right variable is never found
        logger(WARN, "readFromFile: variable % not set in file %, using default value % ", varName, fileName, defaultValue);
        return defaultValue;
    }
}
 
#endif // MERCURYDPM_FILEIO_HELPERS_H