PathFinderConstExpr.h

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/*
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 * and
 *   Neuroinformatics and Cognitive Robotics Labs (NICR) at TU Ilmenau, GERMANY
 * All rights reserved.
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 * Contact: info@mira-project.org
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 */

#ifndef _MIRA_PATHFINDERCONSTEXPR_H_
#define _MIRA_PATHFINDERCONSTEXPR_H_

#include <boost/preprocessor/stringize.hpp>

namespace mira {


constexpr std::string_view findContainingMIRAPath(const std::string_view& path,
                                                  const std::string_view& miraPaths)
{
    auto pathDelim = '/';
    auto pathsDelim = ':';

    const auto& npos = std::string_view::npos;
    size_t pos = 0;
    while (true) {
        size_t to = miraPaths.find(pathsDelim, pos);
        if (to-pos > 1) {
            auto miraPath = miraPaths.substr(pos, to == npos ? npos : to-pos);

            // mirapath must end without trailing '/'
            // but the matching path must be exactly miraPath or continue with a '/' !
            // e.g. mirapath = /home/user/mira
            //      matches    /home/user/mira/any/path
            //      but NOT    /home/user/mira-pkg/any/path

            while (miraPath.back() == pathDelim)
                miraPath = miraPath.substr(0, miraPath.size()-1);

            if (path.compare(miraPath) == 0)
                return miraPath;
            else if (path.size() > miraPath.size()) {
                if ((path.compare(0, miraPath.size(), miraPath) == 0) && (path[miraPath.size()] == pathDelim))
                    return miraPath;
            }
        }

        if (to == npos)
            break;
        else pos = to+1;
    }

    return "";
}

constexpr std::string_view findContainingMIRAPath(const char* path, const char* miraPaths)
{
    return findContainingMIRAPath(std::string_view(path), std::string_view(miraPaths));
}

constexpr std::string_view findContainingMIRAPath(const char* path)
{
#ifndef MIRA_PATHS
    return "";
#endif

    return findContainingMIRAPath(path, BOOST_PP_STRINGIZE(MIRA_PATHS));
}

constexpr std::string_view chopMIRAPath(const std::string_view& path,
                                        const std::string_view& miraPaths)
{
    auto pathDelim = '/';

    auto miraPath = findContainingMIRAPath(path, miraPaths);
    if (miraPath.empty())
        return path;

    auto pathInMiraPath = path.substr(miraPath.size());

    while (!pathInMiraPath.empty() && (pathInMiraPath.front() == pathDelim))
        pathInMiraPath.remove_prefix(1);

    return pathInMiraPath;
}

constexpr const char* chopMIRAPath(const char* path, const char* miraPaths)
{
    return chopMIRAPath(std::string_view(path), std::string_view(miraPaths)).data();
}

constexpr const char* chopMIRAPath(const char* path)
{
#ifndef MIRA_PATHS
    return path;
#endif

    return chopMIRAPath(path, BOOST_PP_STRINGIZE(MIRA_PATHS));
}


}

#endif