/*
 * UNG's Not GNU
 * 
 * Copyright (c) 2011, Jakob Kaivo <jakob@kaivo.net>
 * 
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 */

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

const char *strings_desc = "find printable strings in files";
const char *strings_inv = "strings [-a] [-t format] -[n number] [file...]";

static int strings(FILE * f, int number, char format)
{
	char buf[BUFSIZ];
	char tbuf[BUFSIZ];
	int nread;
	int offset = 0;
	int i;
	int count = 0;

	while (!feof(f)) {
		nread = fread(buf, sizeof(char), BUFSIZ, f);
		for (i = 0; i < nread; i++) {
			if (buf[i] == '\0' || buf[i] == '\n') {
				if (count >= number) {
					switch (format) {
					case 'd':
						printf("%d ", offset - count);
						break;
					case 'o':
						printf("%o ", offset - count);
						break;
					case 'x':
						printf("%x ", offset - count);
						break;
					default:
						break;
					}
					fwrite(tbuf, sizeof(char), count,
					       stdout);
					putchar('\n');
				}
				count = 0;
			} else if (isprint(buf[i])) {
				tbuf[count] = buf[i];
				count++;
			} else {
				count = 0;
			}
			offset++;
		}
	}
	return 0;
}

int main(int argc, char **argv)
{
	int c;
	int number = 4;
	char format = 0;
	char *end;

	while ((c = getopt(argc, argv, ":an:t:")) != -1) {
		switch (c) {
		case 'a':
			// Always scan the entire file
			break;
		case 'n':
			number = strtol(optarg, &end, 10);
			if (end != NULL && strlen(end) > 0)
				return 1;
			break;
		case 't':
			if (strlen(optarg) != 1)
				return 1;
			format = optarg[0];
			break;
		default:
			return 1;
		}
	}

	if ((format != 0 && format != 'd' && format != 'o' && format != 'x')
	    || number < 1)
		return 1;

	if (optind >= argc) {
		strings(stdin, number, format);
	}

	while (optind < argc) {
		FILE *f = fopen(argv[optind], "r");
		strings(f, number, format);
		fclose(f);
		optind++;
	}

	return 0;
}