config.cc

#include <iostream>
#include <fstream>
#include <limits>										// numeric_limits
using namespace std;
#include "config.h"

static bool comments( ifstream & in, string & name ) {
	for ( ;; ) {
		in >> name;
	  if ( in.fail() ) return true;
	  if ( name.substr(0,1) != "#" ) break;
		in.ignore( numeric_limits<int>::max(), '\n' );	// ignore remainder of line
	} // for
	return false;
} // comments

// Process the configuration file to set the simulation parameters.
void processConfigFile( const char * configFile, ConfigParms & cparms ) {
	enum { Parmnum = 10 };
	struct {
		const char * name;								// configuration name
		bool used;										// already supplied ?
		unsigned int & value;							// location to put configuration value
	} parms[Parmnum] = {
		{ "SodaCost", false, cparms.sodaCost },
		{ "NumStudents", false, cparms.numStudents },
		{ "MaxPurchases", false, cparms.maxPurchases },
		{ "NumVendingMachines", false, cparms.numVendingMachines },
		{ "MaxStockPerFlavour", false, cparms.maxStockPerFlavour },
		{ "MaxShippedPerFlavour", false, cparms.maxShippedPerFlavour },
		{ "TimeBetweenShipments", false, cparms.timeBetweenShipments },
		{ "GroupoffDelay", false, cparms.groupoffDelay },
		{ "ParentalDelay", false, cparms.parentalDelay },
		{ "NumCouriers", false, cparms.numCouriers },
	};
	string name;
	int value;
	unsigned int cnt, posn, numOfParm = 0;

	try {
		ifstream in( configFile );						// open the configuration file for input

		for ( cnt = 0 ; cnt < Parmnum; cnt += 1 ) {		// parameter names can appear in any order
		  if ( comments( in, name ) ) break;			// eof ?
			for ( posn = 0; posn < Parmnum && name != parms[posn].name; posn += 1 ); // linear search
		  if ( posn == Parmnum ) break;					// configuration not found ?
		  if ( parms[posn].used ) break;				// duplicate configuration ?
			in >> value;
			if ( value <= 0 ) {
				cerr << "Error: file \"" << configFile << "\" parameter " << name
					 << " value " << value << " must be positive." << endl;
				exit( EXIT_FAILURE );
			} // if
		  if ( in.fail() ) break;
			in.ignore( numeric_limits<int>::max(), '\n' ); // ignore remainder of line
			numOfParm += 1;
			parms[posn].used = true;
			parms[posn].value = value;
		} // for

		if ( numOfParm != Parmnum ) {
			cerr << "Error: file \"" << configFile << "\" is corrupt." << endl;
			exit( EXIT_FAILURE );
		} // if
		if ( ! comments( in, name ) ) {					// ! eof ?
			cerr << "Error: file \"" << configFile << "\" has extraneous data." << endl;
			exit( EXIT_FAILURE );
		} // if
	} catch( uFile::Failure & ) {
		cerr << "Error: could not open input file \"" << configFile << "\"" << endl;
		exit( EXIT_FAILURE );	
	} // try
} // processConfigFile