// Purpose: copy file
//
// Command syntax:
//   $ ./a.out [ size (>= 0) | 'd' (default 20) [ code (>= 0) | 'd' (default 5) [ 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 <fstream.hfa>									// sin/sout
#include <stdlib.hfa>									// convert
#include <string.h>										// strcmp
#include <errno.h>										// errno

// convert(...) throws out_of_range or invalid_argument
ExceptionDecl( cmd_error );

int main( int argc, char * argv[] ) {
	enum { DefaultSize = 20, DefaultCode = 5 };			// global defaults
	// MUST BE INT (NOT UNSIGNED) TO CORRECTLY TEST FOR NEGATIVE VALUES
	intmax_t size = DefaultSize, code = DefaultCode;	// default value
	ifstream infile = stdin;							// default value
	ofstream outfile = stdout;							// default value

	try {
		choose ( argc ) {
		  case 4: case 5:
			try {										// open input file first as output creates file
				open( infile, argv[3] );
			} catch( open_failure * ) {					// open failed ?
				sout | "Error! Could not open input file \"" | argv[3] | "\"";
				throw ExceptionInst( cmd_error );
			} // try
			if ( argc == 5 ) {
				try {
					open( outfile, argv[4] );
				} catch(  open_failure * ) {	// open failed ?
					sout | "Error! Could not open output file \"" | argv[4] | "\"";
					throw ExceptionInst( cmd_error );
				} // try
			} // if
			fallthrough;
		  case 3:
			if ( strcmp( argv[2], "d" ) != 0 ) {		// default ?
				code = convert( argv[2] );
				if ( code < 0 ) throw ExceptionInst( cmd_error ); // invalid ?
			} // if
			fallthrough;
		  case 2:
			if ( strcmp( argv[1], "d" ) != 0 ) {		// default ?
				size = convert( argv[1] );
				if ( size < 0 ) throw ExceptionInst( cmd_error ); // invalid ?
			} // if
			fallthrough;
		  case 1: ;										// defaults
		  default:										// too many arguments
			throw ExceptionInst( cmd_error );
		} // choose
	} catch( exception_t * ) {							// catch any
		exit | "Usage: " | argv[0]
			 | " [ size (>= 0) | 'd' (default " | DefaultSize
			 | ") [ code (>= 0) | 'd' (default " | DefaultCode
			 | ") [ input-file [ output-file ] ] ] ]";
	} // try
	//sout | "size " | size | " code " | code;

	infile | nlOn;										// read newline
	outfile | nlOff;									// no implicit newline

	char ch;
	for () {											// copy input file to output file
		infile | ch;									// read a character
	  if ( eof( infile ) ) break;						// failed/eof ?
		outfile | ch;									// write a character
	} // for
} // main