file_utilities.hpp

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//This file is part of Bertini 2.
//
//bertini2/io/file_utilities.hpp is free software: you can redistribute it and/or modify
//it under the terms of the GNU General Public License as published by
//the Free Software Foundation, either version 3 of the License, or
//(at your option) any later version.
//
//bertini2/io/file_utilities.hpp is distributed in the hope that it will be useful,
//but WITHOUT ANY WARRANTY; without even the implied warranty of
//MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//GNU General Public License for more details.
//
//You should have received a copy of the GNU General Public License
//along with bertini2/io/file_utilities.hpp.  If not, see <http://www.gnu.org/licenses/>.
//
// Copyright(C) Bertini2 Development Team
//
// See <http://www.gnu.org/licenses/> for a copy of the license,
// as well as COPYING.  Bertini2 is provided with permitted
// additional terms in the b2/licenses/ directory.

 
#pragma once
#include <iostream>
#include <fstream>
#include <sstream>
#include <boost/filesystem.hpp>
 
namespace bertini{
 
    namespace fs = boost::filesystem;
 
    using Path = fs::path;  
 
    using ifstream = std::ifstream;  
    inline
    void OpenInFileThrowIfFail(ifstream & in,
                               Path const& input_path)
    {
        using namespace fs;
        try{
            if (exists(input_path))
            {
                if (is_directory(input_path))
                {
                    std::stringstream err_msg;
                    err_msg << "attempting to open file but is a directory, of name '" << input_path.string() << "'";
                    throw std::runtime_error(err_msg.str());
                }
                else
                {
                    in.open(input_path.c_str());
                    if (!in.is_open())
                    {
                        std::stringstream err_msg;
                        err_msg << "file '" << input_path.string() << "' hypothetically exists, but failed to open correctly";
                        throw std::runtime_error(err_msg.str());
                    }
                }
            }
            else
            {
                std::stringstream err_msg;
                err_msg << "attempting to open file which doesn't exist, of name '" << input_path.string() << "'";
                throw std::runtime_error(err_msg.str());
            }
        }
        catch (const filesystem_error& ex)
        {
            std::stringstream err_msg;
            err_msg << "boost::filesystem throw while attempting to open file '" << input_path.string() << "': '" << ex.what() << "'";
            throw std::runtime_error(err_msg.str());
        }
    }

    inline
    std::string FileToString(Path const& input_path)
    {
        ifstream infile;
        OpenInFileThrowIfFail(infile, input_path);
        std::istreambuf_iterator<char> file_begin(infile), file_end;
        std::string contents(file_begin, file_end);
 
        // Treat file contents as UTF-8; drop a leading byte-order mark (EF BB BF)
        // so it is not parsed as a stray leading character.
        if (contents.size() >= 3 &&
            static_cast<unsigned char>(contents[0]) == 0xEF &&
            static_cast<unsigned char>(contents[1]) == 0xBB &&
            static_cast<unsigned char>(contents[2]) == 0xBF)
        {
            contents.erase(0, 3);
        }
 
        return contents;
    }
}