freebsd-dev/games/random/randomize_fd.c

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/*
* Copyright (C) 2003 Sean Chittenden <seanc@FreeBSD.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/types.h>
#include <sys/param.h>
#include <ctype.h>
#include <err.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include "randomize_fd.h"
static struct rand_node *rand_root;
static struct rand_node *rand_tail;
static struct rand_node *
rand_node_allocate(void)
{
struct rand_node *n;
n = (struct rand_node *)malloc(sizeof(struct rand_node));
if (n == NULL)
err(1, "malloc");
n->len = 0;
n->cp = NULL;
n->next = NULL;
return(n);
}
static void
rand_node_free(struct rand_node *n)
{
if (n != NULL) {
if (n->cp != NULL)
free(n->cp);
free(n);
}
}
static void
rand_node_free_rec(struct rand_node *n)
{
if (n != NULL) {
if (n->next != NULL)
rand_node_free_rec(n->next);
rand_node_free(n);
}
}
static void
rand_node_append(struct rand_node *n)
{
if (rand_root == NULL)
rand_root = rand_tail = n;
else {
rand_tail->next = n;
rand_tail = n;
}
}
int
randomize_fd(int fd, int type, int unique, double denom)
{
u_char *buf;
u_int numnode, j, selected, slen;
struct rand_node *n, *prev;
int bufleft, eof, fndstr, ret;
size_t bufc, buflen, i;
ssize_t len;
rand_root = rand_tail = NULL;
bufc = i = 0;
bufleft = eof = fndstr = numnode = ret = 0;
if (type == RANDOM_TYPE_UNSET)
type = RANDOM_TYPE_LINES;
buflen = sizeof(u_char) * MAXBSIZE;
buf = (u_char *)malloc(buflen);
if (buf == NULL)
err(1, "malloc");
while (!eof) {
/* Check to see if we have bits in the buffer */
if (bufleft == 0) {
len = read(fd, buf, buflen);
if (len == -1)
err(1, "read");
else if (len == 0) {
eof++;
break;
} else if ((size_t)len < buflen)
buflen = (size_t)len;
bufleft = (int)len;
}
/* Look for a newline */
for (i = bufc; i <= buflen && bufleft >= 0; i++, bufleft--) {
if (i == buflen) {
if (fndstr) {
if (!eof) {
memmove(buf, &buf[bufc], i - bufc);
i -= bufc;
bufc = 0;
len = read(fd, &buf[i], buflen - i);
if (len == -1)
err(1, "read");
else if (len == 0) {
eof++;
break;
} else if (len < (ssize_t)(buflen - i))
buflen = i + (size_t)len;
bufleft = (int)len;
fndstr = 0;
}
} else {
buflen *= 2;
buf = (u_char *)realloc(buf, buflen);
if (buf == NULL)
err(1, "realloc");
if (!eof) {
len = read(fd, &buf[i], buflen - i);
if (len == -1)
err(1, "read");
else if (len == 0) {
eof++;
break;
} else if (len < (ssize_t)(buflen - i))
buflen = i + (size_t)len;
bufleft = (int)len;
}
}
}
if ((type == RANDOM_TYPE_LINES && buf[i] == '\n') ||
(type == RANDOM_TYPE_WORDS && isspace(buf[i])) ||
(eof && i == buflen - 1)) {
make_token:
n = rand_node_allocate();
if (-1 != (int)i) {
slen = i - (u_long)bufc;
n->len = slen + 2;
n->cp = (u_char *)malloc(slen + 2);
if (n->cp == NULL)
err(1, "malloc");
memmove(n->cp, &buf[bufc], slen);
n->cp[slen] = buf[i];
n->cp[slen + 1] = '\0';
bufc = i + 1;
}
rand_node_append(n);
fndstr = 1;
numnode++;
}
}
}
(void)close(fd);
/* Necessary evil to compensate for files that don't end with a newline */
if (bufc != i) {
i--;
goto make_token;
}
for (i = numnode; i > 0; i--) {
selected = ((int)denom * random())/(((double)RAND_MAX + 1) / numnode);
for (j = 0, prev = n = rand_root; n != NULL; j++, prev = n, n = n->next) {
if (j == selected) {
if (n->cp == NULL)
break;
ret = printf("%.*s", (int)n->len - 1, n->cp);
if (ret < 0)
err(1, "printf");
if (unique) {
if (n == rand_root)
rand_root = n->next;
if (n == rand_tail)
rand_tail = prev;
prev->next = n->next;
rand_node_free(n);
numnode--;
break;
}
}
}
}
fflush(stdout);
if (!unique)
rand_node_free_rec(rand_root);
return(0);
}