main.c

/*
a very simple tool to rearrange bits of every byte to 'encrypt' data
*/

#include<stdio.h>
#include<stdlib.h>
#include"common.h"


int main(int argc, char** argv) 
{
/*
we plan to encrypt data of the text file. First, open the file to be encrypted.
sanity check for possible errors
*/

	if(argc < 3 )
    {
        fprintf(stderr,"not enough input file\n");
        exit(FAILURE);
	}
/*
read maximum of BUFFER_SIZE of data from the file into a buffer in main memory.
*/
	char* text_buffer = calloc(BUFFER_SIZE+1,sizeof(char));
	int cont = 1;
	int i = 0;
	int buffer_size = BUFFER_SIZE; //default buffer size
	while(cont)	
    {
        int s = read_buffer(i,&text_buffer,argv[1]);
        if(s < BUFFER_SIZE) 
        {
            cont = 0; 
            buffer_size = s;  /*last block of data*/
        }
        encrypt(&text_buffer);
        flush_buffer(i,buffer_size,text_buffer,argv[2]);
        i++;
	}
    return 0;
}