Linking to C/C++ (Cont.)

Code Example—Encrypting a File (Cont.)

main.cpp
 
 // main.cpp - Encrypting a file.
 #include  <iostream>
 #include  <fstream>
 #include  "Encrypt.h"
 using namespace std;
  
 const int  BUFSIZE = 2000;
 char  buffer[BUFSIZE];
 unsigned int   count;                   // character count
 unsigned char  encryptCode;

 int main( int argcount, char* args[ ] ) {
   // Read input and output files from the command line.
   if ( argcount < 3 ) {
     cout << "Usage: Encrypt infile outfile" << endl;
     return( -1 );
   }
   cout << "Encryption code [0-255]? ";
   cin  >> encryptCode;
   ifstream  infile(  args[1], ios::binary );
   ofstream  outfile( args[2], ios::binary );
   cout << "Reading " << args[1] << " and creating " << args[2] << endl;
 
   while ( !infile.eof( ) ) {
     infile.read( buffer, BUFSIZE );
     count = infile.gcount( );

     

       
    
      
      
       
      
         
    
    
      
     

    
     outfile.write( buffer, count );
   }
   return( 0 );
 }
Encrypt.h
 
 // Encript.h
 extern "C" {
   void  Encrypt( char* buf, long count, char eChar );
 }
Encrypt.asm
 
 TITLE Encrypt Procedure      (Encrypt.asm)
 .586
 .model  flat, C
 Encrypt PROTO,

     



      
    
      
      
      
         
    
     
      

     

    
 
 .code
   Encrypt PROC,

     



  

  
      
  
  
  
        
    
    
    
 
      
     

    
     mov  esi, buf
     mov  ecx, count
     mov  al,  eChar
 L1: xor  [esi], al
     inc  esi
     loop L1
     ret
 Encrypt ENDP
 END
An Execution Example
 
Find the first N Fibonacci numbers.
Enter the value of N (positive integer):   10 

1  1  2  3  5
8  13  21  34  55






      “I’m not arguing, I’m just explaining why I’m right.”    
      ― Unknown