lib/path_join.cc

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//
// nis-util - NIS Administration Utilities
// Copyright (C) 2012 Peter Miller
//
// This program 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 2 of the License, or (at
// your option) any later version.
//
// This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
//

#include <lib/ac/string.h>
#include <list>

#include <lib/path_join.h>

typedef std::list<rcstring> string_list_t;


static void
split(const rcstring &text, string_list_t &parts)
{
    if (text.empty())
    {
        parts.push_back(".");
        return;
    }
    const char *cp = text.c_str();
    for (;;)
    {
        const char *slash = strchr(cp, '/');
        if (!slash)
        {
            parts.push_back(cp);
            return;
        }
        parts.push_back(rcstring(cp, slash - cp));
        cp = slash + 1;
    }
}


static rcstring
unsplit(string_list_t &parts)
{
    // toss empty parts, except at the start
    {
        string_list_t fixed;
        for
        (
            string_list_t::const_iterator it = parts.begin();
            it != parts.end();
            ++it
        )
        {
            rcstring part = *it;
            if (!part.empty() || it == parts.begin())
                fixed.push_back(part);
        }
        parts = fixed;
    }

    // toss redundant dots
    {
        string_list_t fixed;
        for
        (
            string_list_t::const_iterator it = parts.begin();
            it != parts.end();
            ++it
        )
        {
            rcstring part = *it;
            if (part != ".")
                fixed.push_back(part);
        }
        parts = fixed;
    }

    if (parts.size() == 1 && parts.front().empty())
        return "/";
    if (parts.empty())
        return ".";

    // glue the parts together again
    rcstring result;
    for
    (
        string_list_t::const_iterator it = parts.begin();
        it != parts.end();
        ++it
    )
    {
        rcstring part = *it;
        if (it != parts.begin())
            result += "/";
        result += part;
    }
    return result;
}


rcstring
path_join(const rcstring &lhs, const rcstring &rhs)
{
    string_list_t parts;
    split(lhs, parts);
    split(rhs, parts);
    return unsplit(parts);
}


rcstring
path_join(const rcstring &p1, const rcstring &p2, const rcstring &p3)
{
    string_list_t parts;
    split(p1, parts);
    split(p2, parts);
    split(p3, parts);
    return unsplit(parts);
}


rcstring
path_join(const rcstring &p1, const rcstring &p2, const rcstring &p3,
    const rcstring &p4)
{
    string_list_t parts;
    split(p1, parts);
    split(p2, parts);
    split(p3, parts);
    split(p4, parts);
    return unsplit(parts);
}


// vim: set ts=8 sw=4 et :