acmecert: Fix cryptography bugs.

[utils.git] / findnulls.c

#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>

char buf[65536];

void findnulls(int fd, char *source, int squelch)
{
    int i, ret, n, s, off;
    
    n = 0;
    s = -1;
    off = 0;
    while(1) {
	ret = read(fd, buf, sizeof(buf));
	if(ret < 0) {
	    if(source != NULL)
		perror(source);
	    else
		perror("read");
	    return;
	}
	for(i = 0; i < ret; i++) {
	    if(buf[i] == 0) {
		if(s == -1)
		    s = off + i;
		n++;
	    } else {
		if(n > 0) {
		    if(n > squelch) {
			if(source == NULL)
			    printf("%i %i\n", s, n);
			else
			    printf("%s: %i %i\n", source, s, n);
		    }
		    s = -1;
		    n = 0;
		}
	    }
	}
	off += ret;
	if(ret == 0)
	    break;
    }
    if(n > squelch) {
	if(source == NULL)
	    printf("%i %i\n", s, n);
	else
	    printf("%s: %i %i\n", source, s, n);
    }
}

int main(int argc, char **argv)
{
    int i, c;
    int squelch;
    int fd;
    
    squelch = 1024;
    while((c = getopt(argc, argv, "hs:")) >= 0) {
	switch(c) {
	case 's':
	    squelch = atoi(optarg);
	    break;
	case 'h':
	case '?':
	case ':':
	default:
	    fprintf(stderr, "usage: findnulls [-h] [-s squelch] [FILE...]\n");
	    exit((c == 'h')?0:1);
	}
    }
    if(optind < argc) {
	for(i = optind; i < argc; i++) {
	    if((fd = open(argv[i], O_RDONLY)) < 0) {
		perror(argv[i]);
		continue;
	    }
	    findnulls(fd, argv[i], squelch);
	    close(fd);
	}
    } else {
	findnulls(0, NULL, squelch);
    }
    return(0);
}

/*
 * Local Variables:
 * compile-command: "gcc -Wall -g -o findnulls findnulls.c"
 * End:
 */