Wednesday, January 11, 2012
99 ways to program a hex, Part 3: C89 in K&R style
To separate the style from the version, here's the program, written in C89, using the K&R style.
/*************************************************************************
*
* 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: C89 in K&R style */
#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include <stdlib.h>
#define LINESIZE 16
static void do_dump (FILE *,FILE *);
/****************************************************************/
int main(int argc,char *argv[]) {
if (argc == 1) {
do_dump(stdin,stdout);
} else {
int i;
for (i = 1 ; i < argc ; i++) {
FILE *fp;
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 *fpin,FILE *fpout) {
unsigned char buffer[BUFSIZ],*pbyte;
size_t offset=0,bread,j;
char ascii[LINESIZE + 1];
while((bread = fread(buffer,1,BUFSIZ,fpin)) > 0) {
pbyte = buffer;
while (bread > 0) {
fprintf(fpout,"%08lX: ",(unsigned long)offset);
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) {
size_t i;
for (i = j ; i < LINESIZE ; i++) {
fprintf(fpout," ");
}
}
fprintf(fpout,"%s\n",ascii);
}
if (fflush(fpout) == EOF) {
perror("output");
exit(EXIT_FAILURE);
}
}
}
/***************************************************************/
We have function prototypes, and more appropriate typedefs for some of the variables, but in the K&R style (ick). Lots of software is still written using this style, like Linux, on the grounds that if it was Good Enough™ for Kernighan and Ritchie, then it's Good Enough™ for the rest of us, never mind that Kernighan and Ritchie wrote their software on teletypes, which is near enough to a manual typewriter hooked up to a computer that if I used one, I would try to type as little as possible myself. But personally, I don't use a teletype; I use a real keyboard and a huge monitor with a small font, so I find little use for the K&R style.
