Thread: binary file again

Code:

What kind of parsing stuff do you want to do? I have drafted (but not tested) code which will read the binary file into a linked list of lines that are the equivalent of the output of the "od -x" command.

Thanks pheininger, you can post your code .

Regards.

Originally Posted by Adak

You don't - I wanted it so I could check that the binary input and output was correct, by checking it with fc.

You can delete that part, or save it to another file, or whatever you want.

One of the problems i have with your code is that i want the hex dump 4 chars at one time, like this:

Code:

0000000      ff07    ffff    ffff    ffff    ffff    ffff    ffff    ffff
0000020      06ff    1016    0740    fff3    ffff    ffff    ffff    ffff
0000040      6004    0101    3074    ffff    ffff    ffff    4bff    4200
0000060      331f    0000    0051    fff1    ffff    4bff    4200    011f
0000100      ff04    00ff    0011    0000    ff00    1610    1939    1202

Thanks.

Regards.

Originally Posted by jean.yves

One of the problems i have with your code is that i want the hex dump 4 chars at one time, like this:

Code:

0000000      ff07    ffff    ffff    ffff    ffff    ffff    ffff    ffff
0000020      06ff    1016    0740    fff3    ffff    ffff    ffff    ffff
0000040      6004    0101    3074    ffff    ffff    ffff    4bff    4200
0000060      331f    0000    0051    fff1    ffff    4bff    4200    011f
0000100      ff04    00ff    0011    0000    ff00    1610    1939    1202

Thanks.

Regards.

I don't think the value will be 4 characters long if the value isn't large enough -by default. They are still the same numbers.

Originally Posted by Syscal

I don't think the value will be 4 characters long if the value isn't large enough -by default. They are still the same numbers.

Totally agree with you, but i mean i want to bufferize the data exactly like what they appear with an hex dump tool (example with od -x).

Regards.

Change this line of code:

Code:

printf("%x\t", buff[j]);

to

Code:

printf("%04x\t", buff[j]);

to adjust that.

Originally Posted by Adak

Change this line of code:

Code:

printf("%x\t", buff[j]);

to

Code:

printf("%04x\t", buff[j]);

to adjust that.

I did that but i got a different display than "od -x", please try it and compare the output of the program and the output with an hex dump tool to see the problem.

Regards.

I don't have a hex dump tool (I'm on Windows). I have a hex editor, but it shows different output than your hex dump tool.

What's different, aside from the numbering along the left margin, for the dump tool?

Originally Posted by Adak

I don't have a hex dump tool (I'm on Windows). I have a hex editor, but it shows different output than your hex dump tool.

What's different, aside from the numbering along the left margin, for the dump tool?

You can see the output here:

exec-snapshot.png - 4shared.com - photo sharing - download image

On the left the hex dump tool, on the right our program.
and my program is :

Code:

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

long filesize(FILE *fp); 

int main(int argc, char **argv) {
  int j, n;
  long num, i;
  FILE *fp;
  char *buff;
  char *buff2;

  fp=fopen(argv[1], "rb");  

  if(fp==NULL) {
    printf("Error opening the file");
    return 1;
  }

  printf("\n\n");
  num=filesize(fp);
  //printf("Filesize of file_data is %ld bytes\n", num);

  buff=malloc(num); 
  buff2=malloc(num);
    
  if(buff==NULL) {
    printf("Error allocating memory");
    return 1;
  }

  n = fread(buff, num, 1, fp);
  if(n==0) {
    printf("Error reading the file");
    return 1;
  }

  printf("\n");
  for(j=0;j<num;j++) {
    if(j % 8==0) {
      printf("\n\t");
    }
    sprintf(buff2+j,"%x",buff[j]);
    printf("%04x\t", buff[j]);
  }

  /* just shows another way of printing out 
  the data - many char's are unprintable */
  /* 
  for(i=0;i<num;i++) {
    fputc(buff[i], stdout);
    if(i % 4 == 0 && i) 
      printf("   ");
  }  
  */

  fclose(fp);

  /*fp=fopen("copy1", "wb");
  if(fp==NULL) {
    printf("Error opening copy1 file");
    return 1;
  }
  fwrite(buff, num, 1, fp);
  fclose(fp);
  free(buff);
  free(buff2);

  printf("\n\n\t\t\t     press enter when ready");
  
  i = getchar(); 
  ++i;*/
  
  printf("\n");

  return 0;
}

long filesize(FILE *stream) {
   long curpos, length;

   curpos = ftell(stream);
   fseek(stream, 0L, SEEK_END);
   length = ftell(stream);
   fseek(stream, curpos, SEEK_SET);
   return length;
}

Regards.

Originally Posted by pheininger

When you have it as ASCII characters 4 at a time, what are you going to do next with the data?

Do you want the whitespace between them?

Do you want the address printed every 8 16-words? If so, how do you want it separated from the file data?

It appears that your processor is little endian. So do you want the bytes in hex or the 16-bit words in hex or in 32-bit words in hex?

Do you understand how to manipulate your program in message 1 and 3 to print the data in hexadecimal instead of a string? (Hint: Use the %0x or %0X format in the printf (or fprintf or sprintf) statement.)

I am reluctant at this point to post my draft code because:

1) It is untested.
2) Except for the code you gave in messages 1 and 3, you have not posted any revisions. There is a homework policy in this forum. My code would take you from almost no code to a nearly complete solution (unless of course I have a nasty subtle bug in it that I have not spotted). If you want more help, please show that you can use sprintf( ) into a buffer in hexadecimal format. Or ask specific questions about sprintf( ) and the hexadecimal format conversions.

OK. Here is some partially tested code that does what you probably want but is does NOT do it like the "od -x" command. The following is NOT the code I drafted earlier. It is much closer to the code in messages 1 and 3. Since it is NOT extensively tested, use at your own risk and review comments would be appreciated.

Code:

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

#define FILE_BLOCK 256u
#define HEX_CHAR_PER_BYTE 2u

int
main (int argc, char **argv)
{
   FILE *          in;
   size_t         wordidx;
   size_t         words_read;
   unsigned short filebuff[FILE_BLOCK];
   char           convbuff[FILE_BLOCK*sizeof(filebuff[0])*HEX_CHAR_PER_BYTE+1];

   in = fopen(argv[1], "rb");

   if(in == NULL) {
       fprintf (stderr, "Can't open file.\n");
       return EXIT_FAILURE;
   }

   while ((words_read = fread(filebuff, sizeof(filebuff[0]), FILE_BLOCK, in)) > 0 ) {
       for ( wordidx = 0; wordidx < words_read ; wordidx++)
           sprintf(
              &convbuff[wordidx*sizeof(filebuff[0])*HEX_CHAR_PER_BYTE], 
              "%04X", 
              filebuff[wordidx]
           );
       /* process each convbuff here. */
   }          

   fclose(in);

   return 0;
}

Warnings:
This was written assuming CHAR_BITS is 8 and sizeof(unsigned short) is 2.
If an implementation uses a stack for its automatic variables, this implementation will require more than 512+1024+4+4 and one FILE * bytes on the stack. Make sure you configure your environment for enough stack.
The place I am most likely to have errored is in the %04X format conversion specification. Of course, there are plenty of other places where I could have errored.

Great code pheininger, thanks,

I modify your code to see if it's ok for my problem :

Code:

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

#define FILE_BLOCK 512u
#define HEX_CHAR_PER_BYTE 2u

int
main (int argc, char **argv)
{
   FILE *          in;
   size_t         wordidx;
   size_t         words_read;
   unsigned short filebuff[FILE_BLOCK];
   char           convbuff[FILE_BLOCK*sizeof(filebuff[0])*HEX_CHAR_PER_BYTE];
   int			  i;
   char			  my_len[5];

   in = fopen(argv[1], "rb");

   if(in == NULL) {
       fprintf (stderr, "Can't open file.\n");
       return EXIT_FAILURE;
   }

   while ((words_read = fread(filebuff, FILE_BLOCK, sizeof(filebuff[0]), in) ) > 0 ) {
       for ( wordidx = 0; wordidx < words_read ; wordidx++)
           sprintf(
              &convbuff[wordidx*sizeof(filebuff[0])*HEX_CHAR_PER_BYTE], 
              "%04X", 
              filebuff[wordidx]
           );
	for(i = 0; i < 4; i++)
		my_len[i] = convbuff[i];
	printf("%s\n", my_len);
   }          

   fclose(in);

   return 0;
}

and when i run the program with file_data (which is 4k, so 8 blocks of 512 each), i got just (4 blocks instead of 8):

Code:

$ ./a.out file_data 
FF07
FFFF
3220
1200

Thanks.

if you want the bytes in actual file order, change FILE_BLOCK to 512u and the type of filebuff to unsigned char in the original code.

what did you mean?

Can you give me the output of your program because, it seems that the changes you add, didn't change anything.

Thanks.

Originally Posted by jean.yves

what did you mean?

Can you give me the output of your program because, it seems that the changes you add, didn't change anything.

Thanks.

I have not been running each version.

What I am expecting is that, on a little endian machine, if you use unsigned short version, the my_len[ ] display will look like FF07 and, if you use unsigned char version, the display will look like 07FF. On a big endian machine, they will both display 07FF.

Is that clear?

Originally Posted by pheininger

I have not been running each version.

What I am expecting is that, on a little endian machine, if you use unsigned short version, the my_len[ ] display will look like FF07 and, if you use unsigned char version, the display will look like 07FF. On a big endian machine, they will both display 07FF.

Is that clear?

Thanks for the program i think i can do some intresting stuff with your code .

Regards.