src/InputProvider.cpp

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/* dlvhex -- Answer-Set Programming with external interfaces.
 * Copyright (C) 2005-2007 Roman Schindlauer
 * Copyright (C) 2006-2015 Thomas Krennwallner
 * Copyright (C) 2009-2016 Peter Schüller
 * Copyright (C) 2011-2016 Christoph Redl
 * Copyright (C) 2015-2016 Tobias Kaminski
 * Copyright (C) 2015-2016 Antonius Weinzierl
 *
 * This file is part of dlvhex.
 *
 * dlvhex is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * dlvhex 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with dlvhex; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif                           // HAVE_CONFIG_H

#include "dlvhex2/InputProvider.h"
#include "dlvhex2/URLBuf.h"
#include "dlvhex2/Error.h"

#include <cassert>
#include <fstream>
#include <sstream>

DLVHEX_NAMESPACE_BEGIN

WARNING("TODO use boost::iostream::chain or something similar to create real streaming/incremental input provider")

class InputProvider::Impl
{
    public:
        std::stringstream stream;
        std::vector<std::string> contentNames;

    public:
        Impl() {
        }
};

InputProvider::InputProvider():
pimpl(new Impl)
{
}


InputProvider::~InputProvider()
{
}


void InputProvider::addStreamInput(std::istream& i, const std::string& contentname)
{
    // read the input before adding it to pimpl->stream (otherwise empty input seems to make the overall stream corrupt)
    std::stringstream inp;
    inp << i.rdbuf();
    pimpl->stream << inp.str();
    pimpl->contentNames.push_back(contentname);
}


void InputProvider::addStringInput(const std::string& content, const std::string& contentname)
{
    pimpl->stream << content;
    pimpl->contentNames.push_back(contentname);
}


void InputProvider::addFileInput(const std::string& filename)
{
    std::ifstream ifs;
    ifs.open(filename.c_str());

    if (!ifs.is_open()) {
        throw GeneralError("File " + filename + " not found");
    }

    pimpl->stream << ifs.rdbuf();
    ifs.close();
    pimpl->contentNames.push_back(filename);
}

void InputProvider::addCSVFileInput(const std::string& predicate, const std::string& filename)
{
    std::ifstream ifs;
    ifs.open(filename.c_str());

    std::string line;
    int lineNr = 0;
    while (std::getline(ifs, line)) {
        // replace unquoted semicolons by commas
        bool firstChar = true;
        bool addQuotes = false;
        bool escaped = false;
        pimpl->stream << predicate << "(" << lineNr << ",";
        for (int i = 0; i <= line.length(); ++i){
            // decide type of argument
            if (firstChar && !(line[i] >= '0' && line[i] <= '9')) {
                addQuotes = true;
                pimpl->stream << "\"";
            }
            firstChar = false;

            // detect end of argument
            if ((line[i] == ';' || line[i] == 0) && !escaped){
                if (addQuotes) pimpl->stream << "\"";
                if (line[i] != 0) pimpl->stream << ",";
                addQuotes = false;
                firstChar = true;
            }

            // escape sequence
            else if (line[i] == '\\' && !escaped) {
                pimpl->stream << line[i];
                escaped = true;
            }

            // output ordinary character
            else if (line[i] != 0){
                pimpl->stream << line[i];
                escaped = false;
            }
        }
        // construct fact for this line
        pimpl->stream << ").";

        ++lineNr;
    }

    ifs.close();
    pimpl->contentNames.push_back(filename);
}

#ifdef HAVE_CURL
void InputProvider::addURLInput(const std::string& url)
{
    assert(url.find("http://") == 0 && "currently only processing http:// URLs");

    URLBuf ubuf;
    ubuf.open(url);
    std::istream is(&ubuf);

    pimpl->stream << is.rdbuf();

    if (ubuf.responsecode() == 404) {
        throw GeneralError("Requested URL " + url + " was not found");
    }

    pimpl->contentNames.push_back(url);
}
#endif

bool InputProvider::hasContent() const
{
    return !pimpl->contentNames.empty();
}


const std::vector<std::string>& InputProvider::contentNames() const
{
    return pimpl->contentNames;
}


std::istream& InputProvider::getAsStream()
{
    assert(hasContent() && "should have gotten some content before using content");
    return pimpl->stream;
}


DLVHEX_NAMESPACE_END

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