The Boston Diaries

The ongoing saga of a programmer who doesn't live in Boston, nor does he even like Boston, but yet named his weblog/journal “The Boston Diaries.”

Go figure.

Friday, January 20, 2012

99 ways to program a hex, Part 12: C99, const and restrict correctness, assertive, GCC extenstions

And today's code is identical to part 10 save again for one line—it too uses a GCC extension per yesterday's code.

This also marks the end of the C versions for a couple of days.

/*************************************************************************
*
* Copyright 2012 by Sean Conner.  All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
*
* Comments, questions and criticisms can be sent to: sean@conman.org
*
*************************************************************************/

/* Style: C99, const and restrict correctness, assertive, GCC extenstions */

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

#define LINESIZE	  16

static void 	do_dump		(FILE *const restrict,FILE *const restrict) __attribute__((nonnull,nothrow));

/****************************************************************/

int main(const int argc,char *const restrict argv[])
{
  assert(argc    >= 1);
  assert(argv    != NULL);
  assert(argv[0] != NULL);
  
  if (argc == 1)
    do_dump(stdin,stdout);
  else
  {
    for (int i = 1 ; i < argc ; i++)
    {
      FILE *fp = fopen(argv[i],"rb");
      if (fp == NULL)
      {
        perror(argv[i]);
        continue;
      }

      printf("-----%s-----\n",argv[i]);
      do_dump(fp,stdout);
      fclose(fp);
    }
  }

  return EXIT_SUCCESS;
}

/******************************************************************/

static void do_dump(FILE *const restrict fpin,FILE *const restrict fpout)
{
  unsigned char  buffer[BUFSIZ];
  size_t         offset;
  size_t         bread;
  
  assert(fpin  != NULL);
  assert(fpout != NULL);
  
  offset = 0;

  while((bread = fread(buffer,1,BUFSIZ,fpin)) > 0)
  {
    unsigned char *pbyte = buffer;

    while (bread > 0)
    {
      char ascii[LINESIZE + 1];
      
      fprintf(fpout,"%08lX: ",(unsigned long)offset);
      size_t j = 0;

      do
      {
        fprintf(fpout,"%02X ",*pbyte);
        if (isprint(*pbyte))
          ascii [j] = *pbyte;
        else
          ascii [j] = '.';
        pbyte  ++;
        offset ++;
        j      ++;
        bread  --;
      } while ((j < LINESIZE) && (bread > 0));

      ascii [j] = '\0';

      if (j < LINESIZE)
	for (size_t i = j ; i < LINESIZE ; i++) fprintf(fpout,"   ");

      fprintf(fpout,"%s\n",ascii);      
    }
    
    if (fflush(fpout) == EOF)
    {
      perror("output");
      exit(EXIT_FAILURE);
    }
  }
}

/***************************************************************/

Obligatory Picture

[It's the most wonderful time of the year!]

Obligatory Links

Obligatory Miscellaneous

You have my permission to link freely to any entry here. Go ahead, I won't bite. I promise.

The dates are the permanent links to that day's entries (or entry, if there is only one entry). The titles are the permanent links to that entry only. The format for the links are simple: Start with the base link for this site: http://boston.conman.org/, then add the date you are interested in, say 2000/08/01, so that would make the final URL:

http://boston.conman.org/2000/08/01

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Copyright © 1999-2019 by Sean Conner. All Rights Reserved.