// Purpose: copy file
//
// Command syntax:
//   $ ./a.out [ size (>= 0) [ code (>= 0) [ input-file [ output-file ] ] ] ]
// all parameters are optional. Defaults: size=>20, code=>5, input=>cin, output=>cout
//
// Examples:
//   $ ./a.out 34
//   $ ./a.out 34 0
//   $ ./a.out 34 0 in
//   $ ./a.out 34 0 in out

#include <iostream>
#include <fstream>
#include <sstream>
#include <cstdlib>					// exit
using namespace std;					// direct access to std

bool convert( int &val, char *buffer ) {		// convert C string to integer
    std::stringstream ss( buffer );			// connect stream and buffer
    string temp;
    ss >> dec >> val;					// convert integer from buffer
    return ! ss.fail() &&				// conversion successful ?
	! ( ss >> temp );				// characters after conversion all blank ?
} // convert

enum { sizeDeflt = 20, codeDeflt = 5 };			// global defaults

int main( int argc, char *argv[] ) {
    unsigned int size = sizeDeflt, code = codeDeflt;	// default value
    istream *infile = &cin;				// default value
    ostream *outfile = &cout;				// default value

    infile->exceptions( ios_base::failbit );		// set cin/cout to use exceptions
    outfile->exceptions( ios_base::failbit );
    try {
	switch ( argc ) {
	  case 5:
	    try {
		outfile = new ofstream( argv[4] );	// open output file
		outfile->exceptions( ios_base::failbit ); // set exceptions
	    } catch( ios_base::failure ) {
		throw ios_base::failure( "could not open output file" );
	    } // try
	    // FALL THROUGH
	  case 4:
	    try {
		infile = new ifstream( argv[3] );	// open input file
		infile->exceptions( ios_base::failbit ); // set exceptions
	    } catch( ios_base::failure ) {
		throw ios_base::failure( "could not open input file" );
	    } // try
	    // FALL THROUGH
	  case 3:
	    if ( ! convert( (int &)code, argv[2] ) || (int)code < 0 ) { // invalid integer ?
		throw ios_base::failure( "invalid code" );
	    } // if
	    // FALL THROUGH
	  case 2:
	    if ( ! convert( (int &)size, argv[1] ) || (int)size < 0 ) { // invalid integer ?
		throw ios_base::failure( "invalid size" );
	    } // if
	    // FALL THROUGH
	  case 1:					// all defaults
	    break;
	  default:					// wrong number of options
	    throw ios_base::failure( "wrong number of arguments" );
	} // switch
    } catch( ios_base::failure err ) {
	cerr << err.what() << endl;
	cerr << "Usage: " << argv[0]
	     << " [ size (>= 0 : " << sizeDeflt
	     << ") [ code (>= 0 : " << codeDeflt
	     << ") [ input-file [ output-file ] ] ] ]" << endl;
	exit( EXIT_FAILURE );				// TERMINATE
    } // try

    *infile >> noskipws;				// turn off white space skipping during input

    try {
	char ch;
	for ( ;; ) {					// copy input file to output file
	    *infile >> ch;				// read a character, raise ios_base::failure at EOF
	    *outfile << ch;				// write a character
	} // for
    } catch( ios_base::failure ) {}			// end of file

    if ( infile != &cin ) delete infile;		// close file, do not delete cin!
    if ( outfile != &cout ) delete outfile;		// close file, do not delete cout!
} // main

// Local Variables: //
// compile-command: "g++ IO.cc" //
// End: //