Question

This question has been asked before but the responses have been wrong. Please do not copy and paste their answers. Currently the program opens a file and reads every byte in the file and write both the ASCII hex value for that byte as well as it’s printable character to standard output with non-printable characters printing a "." Now, I want have an option where the program prints in binary instead of hex by typing "-b" at the command line. For instance, ~hexdump -b input.txt(or any name of text file) will result in the binary option and ~hexdump input.txt results in the hex option. Any ideas how to implement this?

This code is done in C.

----------------------------------

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define SIZE 1000

void hexDump(void * addr, int len) {
int i;
unsigned char buffline[17];
unsigned char * pc = (unsigned char * ) addr;
for (i = 0; i < len; i++) {
if ((i % 16) == 0) {
if (i != 0)
printf(" %s\n", buffline);
if (pc[i] == 0x00) {
return; //exit will end the program and you cant modify next line
}
printf(" %07x: ", i); //prints address
}
printf("%02x", pc[i]);
if ((i % 2) == 1)
printf(" ");
if ((pc[i] < 0x20) || (pc[i] > 0x7e)) { //non-printable chars
buffline[i % 16] = '.';
} else {
buffline[i % 16] = pc[i];
}
buffline[(i % 16) + 1] = '\0'; //clear array
}
while ((i % 16) != 0) { //'.' fill last line
printf(" ");
i++;
}
printf(" %s\n", buffline);
}

int main(int argc, char * argv[]) {
FILE * fp;
char buff[SIZE];
int count=1;
fp = fopen(argv[1], "r");
memset(buff, '\0', sizeof(buff));
while(fgets(buff, SIZE, fp)){
hexDump(& buff, sizeof(buff));
}
fclose(fp);;
return 0;

Answer 1

Here is the program . Save it in file hexdump.c and run the program with command line parameter -b input.txt

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define SIZE 1000

// To print binary data of a int value
void print_binary(int number)
{
if (number) {
print_binary(number >> 1);
putc((number & 1) ? '1' : '0', stdout);
}
}

// Add a new parameter char in_binary in the existing function
// if in_binary == 'y' it will display binary dump instead of hex dump
void hexDump (void *addr, int len, char in_binary)
{
int i;
unsigned char buffline[17];
unsigned char *pc = (unsigned char *) addr;
for (i = 0; i < len; i++)
{
if ((i % 16) == 0)
   {
   if (i != 0)
   printf (" %s\n", buffline);
   if (pc[i] == 0x00)
   {
   return;       //exit will end the program and you cant modify next line
   }
   printf (" %07x: ", i);   //prints address
   }
if(in_binary == 'y') {
// print in binary format
print_binary(pc[i]);
} else {
// print in usual hex format
printf ("%02x", pc[i]);
}
  
if ((i % 2) == 1)
   printf (" ");
if ((pc[i] < 0x20) || (pc[i] > 0x7e))
   {           //non-printable chars
   buffline[i % 16] = '.';
   }
else
   {
   buffline[i % 16] = pc[i];
   }
buffline[(i % 16) + 1] = '\0';   //clear array
}
while ((i % 16) != 0)
{               //'.' fill last line
printf (" ");
i++;
}
printf (" %s\n", buffline);
}

int main (int argc, char *argv[])
{
FILE *fp;
char buff[SIZE];
int count = 1;
char in_binary = 'n'; // for 'n' -> do not print in binary
char *filename = "input.txt";
char *binary_option = "-b";
// If command line parameter -b is present dump binary data correspond to ascii
if(strcmp(argv[1], binary_option) == 0) {
in_binary = 'y'; // for 'y' -> do print in binary format
// Collect the filename
filename = argv[2];
} else {
filename = argv[1];
}
  
  
fp = fopen (filename, "r");
memset (buff, '\0', sizeof (buff));
while (fgets (buff, SIZE, fp))
{
hexDump (&buff, sizeof (buff), in_binary);
}
fclose (fp);
return 0;
}

Here is the output in binary

0000000: 11101001101000 11010011110011 1000001101001 1110011100000 1100001100000 11101001100101 11100111110100 1000001101100 this is a test l
0000010: 11010011101110 11001011010 ine.............
0000000: 1100101101110 1100100100000 11011001101001 11011101100101 100000 11101001100101 11100111110100 1000001101100 2nd line. test l
0000010: 11010011101110 11001011010 ine.............

Here is the textfile input.txt content
this is a test line
2nd line

Here is the usual hexdump output

0000000: 7468 6973 2069 7320 6120 7465 7374 206c this is a test l
0000010: 696e 650a 0000 0000 0000 0000 0000 0000 ine.............
0000000: 326e 6420 6c69 6e65 0020 7465 7374 206c 2nd line. test l
0000010: 696e 650a 0000 0000 0000 0000 0000 0000 ine.............