/*
 * isascii - verify that input files consist of ASCII characters only
 * Copyright (C) 2007  Lars Wirzenius <liw@iki.fi>
 * 
 * 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 3 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, see <http://www.gnu.org/licenses/>.
 */


#define _BSD_SOURCE /* For isascii(3).  */

#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <getopt.h>

#include <ctype.h>


#define VERSION "1.0"


/*
 * Code to indicate an invalid UTF8 character.
 */
enum { INVALID_CHAR = 0xffffffff };


/*
 * Determine if the contents of an open file form a valid ASCII byte stream.
 */
static int is_ascii_byte_stream(FILE *file, char *filename, int quiet) {
        int c;
	unsigned long line, col;

        line = 1;
        col = 1;
                
        for (;;) {
                c = getc(file);
    
                if (c == EOF)
                        break;
                else if (c == '\n') {
                        ++line;
                        col = 1;
                } else if (isascii(c)) {
                        ++col;
                } else
                        goto error;
        }

	return 1;
	
error:
	if (!quiet) {
		printf("%s: line %lu, char %lu: invalid ASCII code: 0x%02x\n", 
		       filename, line, col, c);
	}
	return 0;
}


static void usage(const char *program_name) {
	printf("Usage: %s [-hq] [--help] [--quiet] [file ...]\n", 
	       program_name);
	printf("Check whether input files are valid ASCII.\n");
	printf("This is version %s.\n", VERSION);
}


int main(int argc, char **argv) {
	int i, ok;
	FILE *file;

	int quiet;
	struct option options[] = {
		{ "help", no_argument, NULL, 'h' },
		{ "quiet", no_argument, &quiet, 1 },
	};
	int opt;
	
	quiet = 0;
	
	while ((opt = getopt_long(argc, argv, "hq", options, NULL)) != -1) {
		switch (opt) {
		case 0:
			break;
			
		case 'h':
			usage(argv[0]);
			exit(0);
			break;
			
		case 'q':
			quiet = 1;
			break;

		case '?':
			exit(EXIT_FAILURE);

		default:
			abort();
		}
	}

	if (optind == argc)
		ok = is_ascii_byte_stream(stdin, "stdin", quiet);
	else {
		ok = 1;
		for (i = optind; i < argc; ++i) {
			file = fopen(argv[i], "r");
			if (file == NULL) {
				fprintf(stderr, "isascii: %s: error %d: %s\n",
				                argv[i], errno, 
				                strerror(errno));
				ok = 0;
			} else {
			        if (!is_ascii_byte_stream(file, argv[i], quiet))
    			                ok = 0;
				(void) fclose(file);
			}
		}
	}
	
	if (ok)
		exit(0);
	exit(EXIT_FAILURE);
}