/Users/jmonk/Physics/ForIA/src/ConfigurationFile.cxx

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// ConfigurationFile.cxx
// code snippet adapted from: http://www-personal.umich.edu/~wagnerr/ConfigFile.html

#include "ForIA/ConfigurationFile.hh"

using std::string;

namespace ForIA{
  
  /*
  ConfigurationFile::ConfigurationFile( string filename, string delimiter,
                                        string comment, string sentry )
    : myDelimiter(delimiter), myComment(comment), mySentry(sentry)
  {
    // Construct a ConfigurationFile, getting keys and values from given file
    
    std::ifstream in( filename.c_str() );
    
    if( !in ) throw file_not_found( filename ); 
    
    in >> (*this);
  }
  */
  
  ConfigurationFile::ConfigurationFile()
    : myDelimiter( string(1,'=') ), myComment( string(1,'#') )
  {
    // Construct a ConfigurationFile without a file; empty
  }
  
  void ConfigurationFile::init(const string &filename, const string &delimiter, 
                          const string &comment, const string &sentry){
    
    myDelimiter = delimiter;
    myComment = comment;
    mySentry = sentry;
    
    std::ifstream in( filename.c_str() );
    
    if( !in ) throw file_not_found( filename ); 
    
    in >> (*this);
    return;
  }
  
  
  void ConfigurationFile::remove( const string& key )
  {
    // Remove key and its value
    myContents.erase( myContents.find( key ) );
    return;
  }
  
  
  bool ConfigurationFile::keyExists( const string& key ) const
  {
    // Indicate whether key is found
    mapci p = myContents.find( key );
    return ( p != myContents.end() );
  }
  
  
  /* static */
  void ConfigurationFile::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 ConfigurationFile& cf )
  {
    // Save a ConfigurationFile to os
    for( ConfigurationFile::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, ConfigurationFile& cf )
  {
    // Load a ConfigurationFile 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;
                ConfigurationFile::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;
                ConfigurationFile::trim(nlcopy);
                if( nlcopy != "" ) line += "\n";
                line += nextline;
                terminate = false;
              }
            
            // Store key and value
            ConfigurationFile::trim(key);
            ConfigurationFile::trim(line);
            cf.myContents[key] = line;  // overwrites if key is repeated
          }
      }
    
    return is;
  }
}