games/random/randomize_fd.c

   1 /*
   2  * Copyright (C) 2003 Sean Chittenden <seanc@FreeBSD.org>
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  */
  26
  27 #include <sys/cdefs.h>
  28 __FBSDID("$FreeBSD$");
  29
  30 #include <sys/types.h>
  31 #include <sys/param.h>
  32
  33 #include <ctype.h>
  34 #include <err.h>
  35 #include <errno.h>
  36 #include <stdlib.h>
  37 #include <stdio.h>
  38 #include <string.h>
  39 #include <unistd.h>
  40
  41 #include "randomize_fd.h"
  42
  43 static struct rand_node *rand_root;
  44 static struct rand_node *rand_tail;
  45
  46 static struct rand_node *
  47 rand_node_allocate(void)
  48 {
  49         struct rand_node *n;
  50
  51         n = (struct rand_node *)malloc(sizeof(struct rand_node));
  52         if (n == NULL)
  53                 err(1, "malloc");
  54
  55         n->len = 0;
  56         n->cp = NULL;
  57         n->next = NULL;
  58         return(n);
  59 }
  60
  61 static void
  62 rand_node_free(struct rand_node *n)
  63 {
  64         if (n != NULL) {
  65                 if (n->cp != NULL)
  66                         free(n->cp);
  67
  68                 free(n);
  69         }
  70 }
  71
  72 static void
  73 rand_node_free_rec(struct rand_node *n)
  74 {
  75         if (n != NULL) {
  76                 if (n->next != NULL)
  77                         rand_node_free_rec(n->next);
  78
  79                 rand_node_free(n);
  80         }
  81 }
  82
  83 static void
  84 rand_node_append(struct rand_node *n)
  85 {
  86         if (rand_root == NULL)
  87                 rand_root = rand_tail = n;
  88         else {
  89                 rand_tail->next = n;
  90                 rand_tail = n;
  91         }
  92 }
  93
  94 int
  95 randomize_fd(int fd, int type, int unique, double denom)
  96 {
  97         u_char *buf;
  98         u_int slen;
  99         u_long i, j, numnode, selected;
 100         struct rand_node *n, *prev;
 101         int bufleft, eof, fndstr, ret;
 102         size_t bufc, buflen;
 103         ssize_t len;
 104
 105         rand_root = rand_tail = NULL;
 106         bufc = i = 0;
 107         bufleft = eof = fndstr = numnode = ret = 0;
 108
 109         if (type == RANDOM_TYPE_UNSET)
 110                 type = RANDOM_TYPE_LINES;
 111
 112         buflen = sizeof(u_char) * MAXBSIZE;
 113         buf = (u_char *)malloc(buflen);
 114         if (buf == NULL)
 115                 err(1, "malloc");
 116
 117         while (!eof) {
 118                 /* Check to see if we have bits in the buffer */
 119                 if (bufleft == 0) {
 120                         len = read(fd, buf, buflen);
 121                         if (len == -1)
 122                                 err(1, "read");
 123                         else if (len == 0) {
 124                                 eof++;
 125                                 break;
 126                         } else if ((size_t)len < buflen)
 127                                 buflen = (size_t)len;
 128
 129                         bufleft = (int)len;
 130                 }
 131
 132                 /* Look for a newline */
 133                 for (i = bufc; i <= buflen && bufleft >= 0; i++, bufleft--) {
 134                         if (i == buflen) {
 135                                 if (fndstr) {
 136                                         if (!eof) {
 137                                                 memmove(buf, &buf[bufc], i - bufc);
 138                                                 i -= bufc;
 139                                                 bufc = 0;
 140                                                 len = read(fd, &buf[i], buflen - i);
 141                                                 if (len == -1)
 142                                                         err(1, "read");
 143                                                 else if (len == 0) {
 144                                                         eof++;
 145                                                         break;
 146                                                 } else if (len < (ssize_t)(buflen - i))
 147                                                         buflen = i + (size_t)len;
 148
 149                                                 bufleft = (int)len;
 150                                                 fndstr = 0;
 151                                         }
 152                                 } else {
 153                                         buflen *= 2;
 154                                         buf = (u_char *)realloc(buf, buflen);
 155                                         if (buf == NULL)
 156                                                 err(1, "realloc");
 157
 158                                         if (!eof) {
 159                                                 len = read(fd, &buf[i], buflen - i);
 160                                                 if (len == -1)
 161                                                         err(1, "read");
 162                                                 else if (len == 0) {
 163                                                         eof++;
 164                                                         break;
 165                                                 } else if (len < (ssize_t)(buflen - i))
 166                                                         buflen = i + (size_t)len;
 167
 168                                                 bufleft = (int)len;
 169                                         }
 170
 171                                 }
 172                         }
 173
 174                         if ((type == RANDOM_TYPE_LINES && buf[i] == '\n') ||
 175                             (type == RANDOM_TYPE_WORDS && isspace(buf[i])) ||
 176                             (eof && i == buflen - 1)) {
 177                         make_token:
 178                                 if (numnode == RANDOM_MAX_PLUS1) {
 179                                         errno = EFBIG;
 180                                         err(1, "too many delimiters");
 181                                 }
 182                                 numnode++;
 183                                 n = rand_node_allocate();
 184                                 if (-1 != (int)i) {
 185                                         slen = i - (u_long)bufc;
 186                                         n->len = slen + 2;
 187                                         n->cp = (u_char *)malloc(slen + 2);
 188                                         if (n->cp == NULL)
 189                                                 err(1, "malloc");
 190
 191                                         memmove(n->cp, &buf[bufc], slen);
 192                                         n->cp[slen] = buf[i];
 193                                         n->cp[slen + 1] = '\0';
 194                                         bufc = i + 1;
 195                                 }
 196                                 rand_node_append(n);
 197                                 fndstr = 1;
 198                         }
 199                 }
 200         }
 201
 202         (void)close(fd);
 203
 204         /* Necessary evil to compensate for files that don't end with a newline */
 205         if (bufc != i) {
 206                 i--;
 207                 goto make_token;
 208         }
 209
 210         for (i = numnode; i > 0; i--) {
 211                 selected = random() % numnode;
 212
 213                 for (j = 0, prev = n = rand_root; n != NULL; j++, prev = n, n = n->next) {
 214                         if (j == selected) {
 215                                 if (n->cp == NULL)
 216                                         break;
 217
 218                                 if ((int)(denom * random() /
 219                                         RANDOM_MAX_PLUS1) == 0) {
 220                                         ret = printf("%.*s",
 221                                                 (int)n->len - 1, n->cp);
 222                                         if (ret < 0)
 223                                                 err(1, "printf");
 224                                 }
 225                                 if (unique) {
 226                                         if (n == rand_root)
 227                                                 rand_root = n->next;
 228                                         if (n == rand_tail)
 229                                                 rand_tail = prev;
 230
 231                                         prev->next = n->next;
 232                                         rand_node_free(n);
 233                                         numnode--;
 234                                 }
 235                                 break;
 236                         }
 237                 }
 238         }
 239
 240         fflush(stdout);
 241
 242         if (!unique)
 243                 rand_node_free_rec(rand_root);
 244
 245         return(0);
 246 }