/*******************************************************************************
*
* longest_line.c
*        
* AUTHOR:
*   Dan Harkless                                                    <opensource@
*   http://harkless.org/dan/software/                              harkless.org>
* 
* COPYRIGHT:
*   This file is Copyright (C) 1999 by Dan Harkless, and is released under the
*   GNU General Public License <http://www.gnu.org/copyleft/gpl.html>.
*
* USAGE:
*   % longest_line [<file>]
*
* DESCRIPTION:                                                               
*   Prints the length (including the trailing \n, if any) of the longest line in
*   the specified file (or stdin, if none specified).
*                                                                            
* DATE        MODIFICATION
* ==========  ==================================================================
* 1999-04-09  Use strerror() to print exact error that occurs on unopened files.
* 1996-11-19  Original.
*                                                                            
*******************************************************************************/
 

#include <errno.h>   /* for errno */
#include <stdio.h>   /* for fprintf(), etc. */
#include <string.h>  /* for strerror() and strrchr() */


int  main(int  argc, char**  argv) {
    char   c;
    char*  last_slash = strrchr(argv[0], '/');
    char*  our_program_name;
    FILE*  file;
    int    i = 0, longest_line = 0;

    if (last_slash == NULL)
	our_program_name = argv[0];
    else
	our_program_name = last_slash + 1;

    if (argc < 2)
	file = stdin;
    else if (argc > 2) {
	fprintf(stderr, "Usage: %s [<file>]\n", our_program_name);
	return 1;
    }
    else {
	file = fopen(argv[1], "r");
	if (file == NULL) {
	    fprintf(stderr, "%s: \"%s\": %s.\n",
		    our_program_name, argv[1], strerror(errno));
	    return 1;
	}
    }

    while (!feof(file)) {
        c = fgetc(file);
        i++;
        if (c == '\n') {
            if (i > longest_line)
                longest_line = i;
            i = 0;
        }
    }

    printf("%d\n", longest_line);
    return 0;
}