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  * $FreeBSD: src/games/random/randomize_fd.c,v 1.2.2.1 2003/02/15 10:34:35 seanc Exp $
  27  */
  28
  29 #include <sys/types.h>
  30 #include <sys/param.h>
  31
  32 #include <ctype.h>
  33 #include <err.h>
  34 #include <stdlib.h>
  35 #include <stdio.h>
  36 #include <string.h>
  37 #include <unistd.h>
  38
  39 #include "randomize_fd.h"
  40
  41 static struct rand_node *rand_root;
  42 static struct rand_node *rand_tail;
  43
  44 static struct rand_node *
  45 rand_node_allocate(void)
  46 {
  47         struct rand_node *n;
  48
  49         n = (struct rand_node *)malloc(sizeof(struct rand_node));
  50         if (n == NULL)
  51                 err(1, "malloc");
  52
  53         n->len = 0;
  54         n->cp = NULL;
  55         n->next = NULL;
  56         return(n);
  57 }
  58
  59 static void
  60 rand_node_free(struct rand_node *n)
  61 {
  62         if (n != NULL) {
  63                 if (n->cp != NULL)
  64                         free(n->cp);
  65
  66                 free(n);
  67         }
  68 }
  69
  70 static void
  71 rand_node_free_rec(struct rand_node *n)
  72 {
  73         if (n != NULL) {
  74                 if (n->next != NULL)
  75                         rand_node_free_rec(n->next);
  76
  77                 rand_node_free(n);
  78         }
  79 }
  80
  81 static void
  82 rand_node_append(struct rand_node *n)
  83 {
  84         if (rand_root == NULL)
  85                 rand_root = rand_tail = n;
  86         else {
  87                 rand_tail->next = n;
  88                 rand_tail = n;
  89         }
  90 }
  91
  92 int
  93 randomize_fd(int fd, int type, int unique, double denom)
  94 {
  95         u_char *buf, *p;
  96         u_int numnode, j, selected, slen;
  97         struct rand_node *n, *prev;
  98         int bufleft, eof, fndstr, ret;
  99         size_t bufc, buflen, i;
 100         ssize_t len;
 101
 102         rand_root = rand_tail = NULL;
 103         bufc = i = 0;
 104         bufleft = eof = fndstr = numnode = ret = 0;
 105
 106         if (type == RANDOM_TYPE_UNSET)
 107                 type = RANDOM_TYPE_LINES;
 108
 109         buflen = sizeof(u_char) * MAXBSIZE;
 110         buf = (u_char *)malloc(buflen);
 111         if (buf == NULL)
 112                 err(1, "malloc");
 113
 114         while (!eof) {
 115                 /* Check to see if we have bits in the buffer */
 116                 if (bufleft == 0) {
 117                         len = read(fd, buf, buflen);
 118                         if (len == -1)
 119                                 err(1, "read");
 120                         else if (len == 0) {
 121                                 eof++;
 122                                 break;
 123                         } else if ((size_t)len < buflen)
 124                                 buflen = (size_t)len;
 125
 126                         bufleft = (int)len;
 127                 }
 128
 129                 /* Look for a newline */
 130                 for (i = bufc; i <= buflen && bufleft >= 0; i++, bufleft--) {
 131                         if (i == buflen) {
 132                                 if (fndstr) {
 133                                         if (!eof) {
 134                                                 memmove(buf, &buf[bufc], i - bufc);
 135                                                 i -= bufc;
 136                                                 bufc = 0;
 137                                                 len = read(fd, &buf[i], buflen - i);
 138                                                 if (len == -1)
 139                                                         err(1, "read");
 140                                                 else if (len == 0) {
 141                                                         eof++;
 142                                                         break;
 143                                                 } else if (len < (ssize_t)(buflen - i))
 144                                                         buflen = i + (size_t)len;
 145
 146                                                 bufleft = (int)len;
 147                                                 fndstr = 0;
 148                                         }
 149                                 } else {
 150                                         p = (u_char *)realloc(buf, buflen * 2);
 151                                         if (p == NULL)
 152                                                 err(1, "realloc");
 153
 154                                         buf = p;
 155                                         if (!eof) {
 156                                                 len = read(fd, &buf[i], buflen);
 157                                                 if (len == -1)
 158                                                         err(1, "read");
 159                                                 else if (len == 0) {
 160                                                         eof++;
 161                                                         break;
 162                                                 } else if (len < (ssize_t)(buflen - i))
 163                                                         buflen = (size_t)len;
 164
 165                                                 bufleft = (int)len;
 166                                         }
 167
 168                                         buflen *= 2;
 169                                 }
 170                         }
 171
 172                         if ((type == RANDOM_TYPE_LINES && buf[i] == '\n') ||
 173                             (type == RANDOM_TYPE_WORDS && isspace((int)buf[i])) ||
 174                             (eof && i == buflen - 1)) {
 175                         make_token:
 176                                 n = rand_node_allocate();
 177                                 if (-1 != (int)i) {
 178                                         slen = i - (u_long)bufc;
 179                                         n->len = slen + 2;
 180                                         n->cp = (u_char *)malloc(slen + 2);
 181                                         if (n->cp == NULL)
 182                                                 err(1, "malloc");
 183
 184                                         memmove(n->cp, &buf[bufc], slen);
 185                                         n->cp[slen] = buf[i];
 186                                         n->cp[slen + 1] = '\0';
 187                                         bufc = i + 1;
 188                                 }
 189                                 rand_node_append(n);
 190                                 fndstr = 1;
 191                                 numnode++;
 192                         }
 193                 }
 194         }
 195
 196         close(fd);
 197
 198         /* Necessary evil to compensate for files that don't end with a newline */
 199         if (bufc != i) {
 200                 i--;
 201                 goto make_token;
 202         }
 203
 204         for (i = numnode; i > 0; i--) {
 205                 selected = ((int)denom * random())/(((double)RAND_MAX + 1) / numnode);
 206
 207                 for (j = 0, prev = n = rand_root; n != NULL; j++, prev = n, n = n->next) {
 208                         if (j == selected) {
 209                                 if (n->cp == NULL)
 210                                         break;
 211
 212                                 ret = printf("%.*s", (int)n->len - 1, n->cp);
 213                                 if (ret < 0)
 214                                         err(1, "printf");
 215                                 if (unique) {
 216                                         if (n == rand_root)
 217                                                 rand_root = n->next;
 218                                         if (n == rand_tail)
 219                                                 rand_tail = prev;
 220
 221                                         prev->next = n->next;
 222                                         rand_node_free(n);
 223                                         numnode--;
 224                                         break;
 225                                 }
 226                         }
 227                 }
 228         }
 229
 230         fflush(stdout);
 231
 232         if (!unique)
 233                 rand_node_free_rec(rand_root);
 234
 235         return(0);
 236 }