/*
 * strings: show strings inside of a file
 */
#include <stdio.h>
#include <ctype.h>

extern int getopt();
extern int opterr, optind;
extern char *optarg;

main(argc, argv)
char **argv;
{
    register FILE *fd;
    FILE *fopen();
    register c;
    register char *cp;
    char line[180];
    register len=2;

    opterr = 1;
    while ((c=getopt(argc, argv, "l:")) != EOF)
	switch (c) {
	case 'l':   len = atoi(optarg);
		    if (len < 1) {
			fprintf(stderr, "strings: -l length must be > 0\n");
			exit(2);
		    }
		    break;
	default:    fprintf(stderr, "usages: strings [-l length] [file]\n");
		    exit(255);
	}

    if (argc-optind < 1)
	fd = stdin;
    else {
	if ((fd=fopen(argv[optind],"rb")) == NULL) {
	    fprintf(stderr, "strings: cannot open %s\n", argv[optind]);
	    exit(1);
	}
    }
    cp = NULL;
    while ((c=getc(fd)) != EOF) {
	if ((c == 0 || c == '\n') && cp && cp >= len+line) {
	    *cp = 0;
	    puts(line);
	}
	else if (c >= ' ' && c <= '~') {
	    if (cp == NULL)
		cp = line;
	    else if (cp >= line+sizeof(line)-2) {
		*cp++ = '\\';
		*cp = 0;
		puts(line);
		cp = line;
	    }
	    *cp++ = c;
	    continue;
	}
	else while ((c=getc(fd)) != 0)
	    if (c == EOF)
		break;
	cp = NULL;
    }
} /* strings */