ConfigFile.cpp

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/*
 * ConfigFile.cpp
 *
 * Class for reading named values from configuration files
 * Richard J. Wagner  v2.1  24 May 2004  wagnerr@umich.edu
 *
 * Copyright (c) 2004 Richard J. Wagner
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to
 * deal in the Software without restriction, including without limitation the
 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
 * sell copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 *
 */

#include "ibrcommon/config.h"
#include "ibrcommon/data/ConfigFile.h"

namespace ibrcommon
{
        ConfigFile::ConfigFile( string filename, string delimiter,
                                                        string comment, string sentry )
                : myDelimiter(delimiter), myComment(comment), mySentry(sentry)
        {
                // Construct a ConfigFile, getting keys and values from given file

                std::ifstream in( filename.c_str() );

                if( !in ) throw file_not_found( filename );

                in >> (*this);
        }


        ConfigFile::ConfigFile()
                : myDelimiter( string(1,'=') ), myComment( string(1,'#') )
        {
                // Construct a ConfigFile without a file; empty
        }


        void ConfigFile::remove( const string& key )
        {
                // Remove key and its value
                myContents.erase( myContents.find( key ) );
                return;
        }


        bool ConfigFile::keyExists( const string& key ) const
        {
                // Indicate whether key is found
                mapci p = myContents.find( key );
                return ( p != myContents.end() );
        }


        /* static */
        void ConfigFile::trim( string& s )
        {
                // Remove leading and trailing whitespace
                static const char whitespace[] = " \n\t\v\r\f";
                s.erase( 0, s.find_first_not_of(whitespace) );
                s.erase( s.find_last_not_of(whitespace) + 1U );
        }


        std::ostream& operator<<( std::ostream& os, const ConfigFile& cf )
        {
                // Save a ConfigFile to os
                for( ConfigFile::mapci p = cf.myContents.begin();
                         p != cf.myContents.end();
                         ++p )
                {
                        os << p->first << " " << cf.myDelimiter << " ";
                        os << p->second << std::endl;
                }
                return os;
        }


        std::istream& operator>>( std::istream& is, ConfigFile& cf )
        {
                // Load a ConfigFile from is
                // Read in keys and values, keeping internal whitespace
                typedef string::size_type pos;
                const string& delim  = cf.myDelimiter;  // separator
                const string& comm   = cf.myComment;    // comment
                const string& sentry = cf.mySentry;     // end of file sentry
                const pos skip = delim.length();        // length of separator

                string nextline = "";  // might need to read ahead to see where value ends

                while( is || nextline.length() > 0 )
                {
                        // Read an entire line at a time
                        string line;
                        if( nextline.length() > 0 )
                        {
                                line = nextline;  // we read ahead; use it now
                                nextline = "";
                        }
                        else
                        {
                                std::getline( is, line );
                        }

                        // Ignore comments
                        line = line.substr( 0, line.find(comm) );

                        // Check for end of file sentry
                        if( sentry != "" && line.find(sentry) != string::npos ) return is;

                        // Parse the line if it contains a delimiter
                        pos delimPos = line.find( delim );
                        if( delimPos < string::npos )
                        {
                                // Extract the key
                                string key = line.substr( 0, delimPos );
                                line.replace( 0, delimPos+skip, "" );

                                // See if value continues on the next line
                                // Stop at blank line, next line with a key, end of stream,
                                // or end of file sentry
                                bool terminate = false;
                                while( !terminate && is )
                                {
                                        std::getline( is, nextline );
                                        terminate = true;

                                        string nlcopy = nextline;
                                        ConfigFile::trim(nlcopy);
                                        if( nlcopy == "" ) continue;

                                        nextline = nextline.substr( 0, nextline.find(comm) );
                                        if( nextline.find(delim) != string::npos )
                                                continue;
                                        if( sentry != "" && nextline.find(sentry) != string::npos )
                                                continue;

                                        nlcopy = nextline;
                                        ConfigFile::trim(nlcopy);
                                        if( nlcopy != "" ) line += "\n";
                                        line += nextline;
                                        terminate = false;
                                }

                                // Store key and value
                                ConfigFile::trim(key);
                                ConfigFile::trim(line);
                                cf.myContents[key] = line;  // overwrites if key is repeated
                        }
                }

                return is;
        }
}