main.cpp

简单实用的文件加密软件及其源代码.使用C++在控制台实现.

//Main.cpp
//
#include <iostream>
#include <fstream>
using namespace std;


#include "Main.h"

//宏定义
#define BUFFER_SIZE					128

//程序流程状态
#define	EXIT						-1
#define INPUT						0
#define PROCESS						1
#define	QUIT						3
#define	MENU						4
#define	SHOW						5

//全局变量
int	program_state=MENU; 
//int	program_state=INPUT; 

char szSourceFilename[128]="2.txt";									//源文文件名
char szCryptographFilename[128]="3.txt";							//密文文件名
char cKey=(char)0x97;												//密钥

void main ()
{
	cout<<"Welcome here!"<<endl;
	cout<<"Example of inputing filename: c:/boot.ini"<<endl;
	cout<<"Can I help you?"<<endl;
	do
	{
		switch (program_state)
		{
		case MENU:
			Menu ();
			break;
		case SHOW:
			Show ();
			program_state = MENU;
			break;
		case INPUT:
			Input ();
			program_state = PROCESS;
			break;
		case PROCESS:
			try
			{
				cout<<"Processing..."<<endl;
				Process ();
				cout<<"Process end"<<endl;
			}
			catch (int)
			{
				cout<<"Error!"<<endl;
			}
			
			program_state = MENU;
			
			break;
		case QUIT:
			if (Quit ())
			{
				program_state = EXIT;
			}
			else
			{
				program_state = MENU;
			}
			break;
		default:
			program_state = MENU;
		}
	}while (program_state != EXIT);

	cout<<"See you next time"<<endl;
		
}
void Menu ()
{
	int nID;
	try
	{
		cout<<"1: File encrypt"<<endl;
		cout<<"2: Opening file"<<endl;
		cout<<"3: Exit program"<<endl;
		cout<<"Please input 1/2/3:";
		cin>>nID;		
	}
	catch (istream)
	{
		cout<<"\"cin\" error "<<endl;
		program_state = EXIT;
		return;
	}
	catch (ostream)
	{
		cout<<"\"cout\" error "<<endl;
		program_state = EXIT;
	}
	switch (nID)
	{
	case 1:
		program_state=INPUT; 
		break;
	case 2:
		program_state=SHOW; 
		break;
	case 3:
		program_state=QUIT; 
		break;
	default:
		;
	}
	
}
void Show ()
{
	try
	{
		char buffer[128];
		cout<<"Please input filename:";
		cin>>buffer;
		ShowFile (buffer);
	}
	catch (char)
	{
		cout<<"File countn't find"<<endl;
	}
}
void ShowFile (char *pszSourceFilename)
{
	ifstream infile;
	infile.open (pszSourceFilename, ios::in);
	if (!infile) 
	{
		throw '0';
	}
	char buffer[128+1]={0};
	while (infile.eof () == false)
	{
		for (int i=0; i<128; i++)
		{
			buffer[i] = '\0';
		}
		infile.read (buffer,128);
		cout<<buffer;
	}
	cout<<endl;
	infile.close ();
}
void Input ()
{

	cout<<"Please input source filename:";
	cin>>szSourceFilename;

	cout<<"Please input crytograph filename:";
	cin>>szCryptographFilename;

	cout<<"Please input key that from -127 to 128:";
	cin>>cKey;

}
void Process ()
{
	try
	{
		Encrypt (szCryptographFilename, szSourceFilename, cKey);
	}
	catch (int)
	{
		cout<<"Reading source file error!"<<endl;
		throw 1;
	}
	catch (char)
	{
		cout<<"Reading crytograph file error!"<<endl;
		throw 1;
	}
}
bool Quit ()
{
	char ch;
	do
	{
		cout<<"Do you sure exit? y/n:";
		cin>>ch;
		cout<<endl;
		ch = (ch >= 'A' && ch <= 'Z') ? ch + 32 : ch;
	}while (ch != 'y' && ch != 'n');
	if (ch == 'y')
	{
		return true;
	}
	return false;
}
void Encrypt (char * pszCryptographFilename, char * pszSourceFilename, char cKey)
{
	ifstream infile;
	infile.open (pszSourceFilename, ios::in | ios::binary);
	if (!infile) 
	{
		throw (int)cKey;
	}
	
	ofstream outfile;
	outfile.open (pszCryptographFilename, ios::out | ios::binary);
	if (!outfile) 
	{
		infile.close ();
		throw cKey;
	}
	

	char buffer[BUFFER_SIZE]={0};
	
	while (infile.eof ()==false)
	{
		for (int i=0; i<BUFFER_SIZE; i++)
		{
			buffer[i] ='\0';
		}

		infile.read (buffer, BUFFER_SIZE);

		if (infile.eof ()==true)
		{
			int i=0;
			while (buffer[i] != '\0')
			{
				buffer[i++] ^= cKey;
			}
			outfile.write (buffer, i);
			infile.close ();
			outfile.close ();
			return;
		}
		for (i=0; i<BUFFER_SIZE; i++);
		{
			if (cKey % i == 0)
			{
				buffer[i] ^= 0x19;
			}
			else
			{
				buffer[i] ^= cKey;
			}
		}
		outfile.write (buffer, BUFFER_SIZE);
	}
	infile.close ();
	outfile.close ();
}