Listing 2: Member functions of command_line

/***************************************************
  FILE NAME   : cline.cpp
  AUTHOR      : Matt Weisfeld                     
                                                  
  DESCRIPTION : building a command line
***************************************************/
#include <iostream.h>
#include <string.h>
#include <stdlib.h>
#include <ctype.h>
#include "cline.hpp"
//  DESCRIPTION  : default constructor
command_line::command_line() {
	command_buffer = new char [1];
	if (command_buffer == NULL) {
		cout << "Error: nospace" << endl;
		exit(0);
	}
	command_buffer[0] = '\0';
	Cargc = 0;
	Cargv = new char * [1];
	Cargv[0] = NULL;
}
//  DESCRIPTION  : initialization constructor
command_line::command_line(const char *command_string) {
	command_buffer = new char [1];
	if (command_buffer == NULL) {
		cout << "Error: nospace" << endl;
		exit(0);
	}
	Cargc = 0;
	Cargv = new char * [1];
	Cargv[0] = NULL;
	build_command(command_string);
}
//  DESCRIPTION  : copy constructor
command_line::command_line(const command_line& ccommand_line) {
	command_buffer = new char [1];
	if (command_buffer == NULL) {
		cout << "Error: nospace" << endl;
		exit(0);
	}
	Cargc = 0;
	Cargv = new char * [1];
	Cargv[0] = NULL;
	build_command(ccommand_line.command_buffer);
}
//  DESCRIPTION  : destructor
command_line::~command_line() {
	delete [] command_buffer;
	for (int i = 0; Cargv[i] != '\0'; i++) {
		delete [] Cargv[i];
	}
	delete [] Cargv;
}
//  DESCRIPTION  : assignment operator for class
command_line& command_line::operator=(const command_line& ccommand_line)
{
	strcpy (command_buffer, ccommand_line.command_buffer);
	for (int i = 0; i != Cargc; i++) {
		delete [] Cargv[i];
	}
	delete [] Cargv;
	build_command(command_buffer);
	return *this;
}
//  DESCRIPTION  : assignment operator for char *
command_line& command_line::operator=(const char *command_string)
{
	strcpy (command_buffer, command_string);
	for (int i = 0; i != Cargc; i++) {
		delete [] Cargv[i];
	}
	delete [] Cargv;
	build_command(command_buffer);
	return *this;
}
//  DESCRIPTION  : print the Cargv information
void command_line::print() {
	cout << "******* start print *******" << endl;
	cout << "Cargc = " << Cargc << endl;
	cout << "command_buffer = " << command_buffer << endl;
	for (int i = 0; Cargv[i] != NULL; i++) {
		cout << "Cargv[" << i << "] = " << Cargv[i] << endl;
	}
	cout << "******** end print ********" << endl;
}
//  DESCRIPTION  : convert a char * to a char **
//		   (Cargv-like structure)
void command_line::build_command(const char *command_string){
	int index = 0, pos=0;
	char buffer[200];
	// delete old memory and get some new memory for command_buffer
	delete [] command_buffer;
	command_buffer =  new char [strlen(command_string)+1];
	if (command_buffer == NULL) {
		cout << "Error: nospace" << endl;
		exit(0);
	}
	strcpy (command_buffer, command_string);
	// get the number of tokens
	strtokens(command_string);
	// delete the space for the old command_line
	for (int i = 0; Cargv[i] != '\0'; i++) {
		delete [] Cargv[i];
	}
	delete [] Cargv;
	/* get space for the new command line */
	Cargv = (char **) new char * [Cargc+1];
	if (Cargv == NULL) {
		cout << "Error: no space" << endl;
		exit(0);
	}
	// flush the white space
	while ( isspace(*command_string) )
		command_string++;
	index = 0;
	// start the loop to build all the individual tokens
	while (*command_string != '\0') {
		pos = 0;
		// copy the token until white space is found
		while ( !isspace(*command_string) && *command_string != '\0') {
			buffer[pos++] = *command_string++;
		}
		buffer[pos] = '\0';
		// get space for the individual tokens
		Cargv[index] = (char *) new char [strlen(buffer)+1];
		if (Cargv[index] == NULL) {
			cout << "Error: nospace" << endl;
			exit(0);
		}
		// copy the token
		strcpy (Cargv[index++], buffer);
		// flush while space
		while ( isspace(*command_string) )
			command_string++;
	}
	// finish by setting the las pointer to NULL
	Cargv[Cargc] = NULL;
}
//  DESCRIPTION  : determine the number of tokens in the char *
void command_line::strtokens(const char *command_string)
{
	int count = 0;
	const char *temp;
	temp = command_string;
	/* bypass white space */
	while (isspace(*temp)) temp++;
	for (count=0; *temp != '\0'; count++) {
		/* continue until white space of string terminator is found */
		while ((!isspace(*temp)) && (*temp != '\0')) temp++;
		/* bypass white space */
		while (isspace(*temp)) temp++;
		
	}
	Cargc = count;
}