src/common/container.h

   1 /* Copyright (c) 2003-2004, Roger Dingledine
   2  * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
   3  * Copyright (c) 2007-2010, The Tor Project, Inc. */
   4 /* See LICENSE for licensing information */
   5
   6 #ifndef _TOR_CONTAINER_H
   7 #define _TOR_CONTAINER_H
   8
   9 #include "util.h"
  10
  11 /** A resizeable list of pointers, with associated helpful functionality.
  12  *
  13  * The members of this struct are exposed only so that macros and inlines can
  14  * use them; all access to smartlist internals should go through the functions
  15  * and macros defined here.
  16  **/
  17 typedef struct smartlist_t {
  18   /** <b>list</b> has enough capacity to store exactly <b>capacity</b> elements
  19    * before it needs to be resized.  Only the first <b>num_used</b> (\<=
  20    * capacity) elements point to valid data.
  21    */
  22   void **list;
  23   int num_used;
  24   int capacity;
  25 } smartlist_t;
  26
  27 smartlist_t *smartlist_create(void);
  28 void smartlist_free(smartlist_t *sl);
  29 void smartlist_clear(smartlist_t *sl);
  30 void smartlist_add(smartlist_t *sl, void *element);
  31 void smartlist_add_all(smartlist_t *sl, const smartlist_t *s2);
  32 void smartlist_remove(smartlist_t *sl, const void *element);
  33 void *smartlist_pop_last(smartlist_t *sl);
  34 void smartlist_reverse(smartlist_t *sl);
  35 void smartlist_string_remove(smartlist_t *sl, const char *element);
  36 int smartlist_isin(const smartlist_t *sl, const void *element) ATTR_PURE;
  37 int smartlist_string_isin(const smartlist_t *sl, const char *element)
  38   ATTR_PURE;
  39 int smartlist_string_pos(const smartlist_t *, const char *elt) ATTR_PURE;
  40 int smartlist_string_isin_case(const smartlist_t *sl, const char *element)
  41   ATTR_PURE;
  42 int smartlist_string_num_isin(const smartlist_t *sl, int num) ATTR_PURE;
  43 int smartlist_digest_isin(const smartlist_t *sl, const char *element)
  44   ATTR_PURE;
  45 int smartlist_overlap(const smartlist_t *sl1, const smartlist_t *sl2)
  46   ATTR_PURE;
  47 void smartlist_intersect(smartlist_t *sl1, const smartlist_t *sl2);
  48 void smartlist_subtract(smartlist_t *sl1, const smartlist_t *sl2);
  49
  50 /* smartlist_choose() is defined in crypto.[ch] */
  51 #ifdef DEBUG_SMARTLIST
  52 /** Return the number of items in sl.
  53  */
  54 static INLINE int smartlist_len(const smartlist_t *sl) ATTR_PURE;
  55 static INLINE int smartlist_len(const smartlist_t *sl) {
  56   tor_assert(sl);
  57   return (sl)->num_used;
  58 }
  59 /** Return the <b>idx</b>th element of sl.
  60  */
  61 static INLINE void *smartlist_get(const smartlist_t *sl, int idx) ATTR_PURE;
  62 static INLINE void *smartlist_get(const smartlist_t *sl, int idx) {
  63   tor_assert(sl);
  64   tor_assert(idx>=0);
  65   tor_assert(sl->num_used > idx);
  66   return sl->list[idx];
  67 }
  68 static INLINE void smartlist_set(smartlist_t *sl, int idx, void *val) {
  69   tor_assert(sl);
  70   tor_assert(idx>=0);
  71   tor_assert(sl->num_used > idx);
  72   sl->list[idx] = val;
  73 }
  74 #else
  75 #define smartlist_len(sl) ((sl)->num_used)
  76 #define smartlist_get(sl, idx) ((sl)->list[idx])
  77 #define smartlist_set(sl, idx, val) ((sl)->list[idx] = (val))
  78 #endif
  79
  80 /** Exchange the elements at indices <b>idx1</b> and <b>idx2</b> of the
  81  * smartlist <b>sl</b>. */
  82 static INLINE void smartlist_swap(smartlist_t *sl, int idx1, int idx2)
  83 {
  84   if (idx1 != idx2) {
  85     void *elt = smartlist_get(sl, idx1);
  86     smartlist_set(sl, idx1, smartlist_get(sl, idx2));
  87     smartlist_set(sl, idx2, elt);
  88   }
  89 }
  90
  91 void smartlist_del(smartlist_t *sl, int idx);
  92 void smartlist_del_keeporder(smartlist_t *sl, int idx);
  93 void smartlist_insert(smartlist_t *sl, int idx, void *val);
  94 void smartlist_sort(smartlist_t *sl,
  95                     int (*compare)(const void **a, const void **b));
  96 void *smartlist_get_most_frequent(const smartlist_t *sl,
  97                     int (*compare)(const void **a, const void **b));
  98 void smartlist_uniq(smartlist_t *sl,
  99                     int (*compare)(const void **a, const void **b),
 100                     void (*free_fn)(void *elt));
 101
 102 void smartlist_sort_strings(smartlist_t *sl);
 103 void smartlist_sort_digests(smartlist_t *sl);
 104 void smartlist_sort_digests256(smartlist_t *sl);
 105
 106 char *smartlist_get_most_frequent_string(smartlist_t *sl);
 107 char *smartlist_get_most_frequent_digest256(smartlist_t *sl);
 108
 109 void smartlist_uniq_strings(smartlist_t *sl);
 110 void smartlist_uniq_digests(smartlist_t *sl);
 111 void smartlist_uniq_digests256(smartlist_t *sl);
 112 void *smartlist_bsearch(smartlist_t *sl, const void *key,
 113                         int (*compare)(const void *key, const void **member))
 114   ATTR_PURE;
 115 int smartlist_bsearch_idx(const smartlist_t *sl, const void *key,
 116                           int (*compare)(const void *key, const void **member),
 117                           int *found_out);
 118
 119 void smartlist_pqueue_add(smartlist_t *sl,
 120                           int (*compare)(const void *a, const void *b),
 121                           int idx_field_offset,
 122                           void *item);
 123 void *smartlist_pqueue_pop(smartlist_t *sl,
 124                            int (*compare)(const void *a, const void *b),
 125                            int idx_field_offset);
 126 void smartlist_pqueue_remove(smartlist_t *sl,
 127                              int (*compare)(const void *a, const void *b),
 128                              int idx_field_offset,
 129                              void *item);
 130 void smartlist_pqueue_assert_ok(smartlist_t *sl,
 131                                 int (*compare)(const void *a, const void *b),
 132                                 int idx_field_offset);
 133
 134 #define SPLIT_SKIP_SPACE   0x01
 135 #define SPLIT_IGNORE_BLANK 0x02
 136 #define SPLIT_STRIP_SPACE  0x04
 137 int smartlist_split_string(smartlist_t *sl, const char *str, const char *sep,
 138                            int flags, int max);
 139 char *smartlist_join_strings(smartlist_t *sl, const char *join, int terminate,
 140                              size_t *len_out) ATTR_MALLOC;
 141 char *smartlist_join_strings2(smartlist_t *sl, const char *join,
 142                               size_t join_len, int terminate, size_t *len_out)
 143   ATTR_MALLOC;
 144
 145 /** Iterate over the items in a smartlist <b>sl</b>, in order.  For each item,
 146  * assign it to a new local variable of type <b>type</b> named <b>var</b>, and
 147  * execute the statement <b>cmd</b>.  Inside the loop, the loop index can
 148  * be accessed as <b>var</b>_sl_idx and the length of the list can be accessed
 149  * as <b>var</b>_sl_len.
 150  *
 151  * NOTE: Do not change the length of the list while the loop is in progress,
 152  * unless you adjust the _sl_len variable correspondingly.  See second example
 153  * below.
 154  *
 155  * Example use:
 156  * <pre>
 157  *   smartlist_t *list = smartlist_split("A:B:C", ":", 0, 0);
 158  *   SMARTLIST_FOREACH(list, char *, cp,
 159  *   {
 160  *     printf("%d: %s\n", cp_sl_idx, cp);
 161  *     tor_free(cp);
 162  *   });
 163  *   smartlist_free(list);
 164  * </pre>
 165  *
 166  * Example use (advanced):
 167  * <pre>
 168  *   SMARTLIST_FOREACH(list, char *, cp,
 169  *   {
 170  *     if (!strcmp(cp, "junk")) {
 171  *       tor_free(cp);
 172  *       SMARTLIST_DEL_CURRENT(list, cp);
 173  *     }
 174  *   });
 175  * </pre>
 176  */
 177 /* Note: these macros use token pasting, and reach into smartlist internals.
 178  * This can make them a little daunting. Here's the approximate unpacking of
 179  * the above examples, for entertainment value:
 180  *
 181  * <pre>
 182  * smartlist_t *list = smartlist_split("A:B:C", ":", 0, 0);
 183  * {
 184  *   int cp_sl_idx, cp_sl_len = smartlist_len(list);
 185  *   char *cp;
 186  *   for (cp_sl_idx = 0; cp_sl_idx < cp_sl_len; ++cp_sl_idx) {
 187  *     cp = smartlist_get(list, cp_sl_idx);
 188  *     printf("%d: %s\n", cp_sl_idx, cp);
 189  *     tor_free(cp);
 190  *   }
 191  * }
 192  * smartlist_free(list);
 193  * </pre>
 194  *
 195  * <pre>
 196  * {
 197  *   int cp_sl_idx, cp_sl_len = smartlist_len(list);
 198  *   char *cp;
 199  *   for (cp_sl_idx = 0; cp_sl_idx < cp_sl_len; ++cp_sl_idx) {
 200  *     cp = smartlist_get(list, cp_sl_idx);
 201  *     if (!strcmp(cp, "junk")) {
 202  *       tor_free(cp);
 203  *       smartlist_del(list, cp_sl_idx);
 204  *       --cp_sl_idx;
 205  *       --cp_sl_len;
 206  *     }
 207  *   }
 208  * }
 209  * </pre>
 210  */
 211 #define SMARTLIST_FOREACH_BEGIN(sl, type, var)  \
 212   STMT_BEGIN                                                    \
 213     int var ## _sl_idx, var ## _sl_len=(sl)->num_used;          \
 214     type var;                                                   \
 215     for (var ## _sl_idx = 0; var ## _sl_idx < var ## _sl_len;   \
 216          ++var ## _sl_idx) {                                    \
 217       var = (sl)->list[var ## _sl_idx];
 218
 219 #define SMARTLIST_FOREACH_END(var)              \
 220     var = NULL;                                 \
 221   } STMT_END
 222
 223 #define SMARTLIST_FOREACH(sl, type, var, cmd)                   \
 224   SMARTLIST_FOREACH_BEGIN(sl,type,var) {                        \
 225     cmd;                                                        \
 226   } SMARTLIST_FOREACH_END(var)
 227
 228 /** Helper: While in a SMARTLIST_FOREACH loop over the list <b>sl</b> indexed
 229  * with the variable <b>var</b>, remove the current element in a way that
 230  * won't confuse the loop. */
 231 #define SMARTLIST_DEL_CURRENT(sl, var)          \
 232   STMT_BEGIN                                    \
 233     smartlist_del(sl, var ## _sl_idx);          \
 234     --var ## _sl_idx;                           \
 235     --var ## _sl_len;                           \
 236   STMT_END
 237
 238 /** Helper: While in a SMARTLIST_FOREACH loop over the list <b>sl</b> indexed
 239  * with the variable <b>var</b>, replace the current element with <b>val</b>.
 240  * Does not deallocate the current value of <b>var</b>.
 241  */
 242 #define SMARTLIST_REPLACE_CURRENT(sl, var, val) \
 243   STMT_BEGIN                                    \
 244     smartlist_set(sl, var ## _sl_idx, val);     \
 245   STMT_END
 246
 247 /* Helper: Given two lists of items, possibly of different types, such that
 248  * both lists are sorted on some common field (as determined by a comparison
 249  * expression <b>cmpexpr</b>), and such that one list (<b>sl1</b>) has no
 250  * duplicates on the common field, loop through the lists in lockstep, and
 251  * execute <b>unmatched_var2</b> on items in var2 that do not appear in
 252  * var1.
 253  *
 254  * WARNING: It isn't safe to add remove elements from either list while the
 255  * loop is in progress.
 256  *
 257  * Example use:
 258  *  SMARTLIST_FOREACH_JOIN(routerstatus_list, routerstatus_t *, rs,
 259  *                     routerinfo_list, routerinfo_t *, ri,
 260  *                     memcmp(rs->identity_digest, ri->identity_digest, 20),
 261  *                     log_info(LD_GENERAL,"No match for %s", ri->nickname)) {
 262  *    log_info(LD_GENERAL, "%s matches routerstatus %p", ri->nickname, rs);
 263  * } SMARTLIST_FOREACH_JOIN_END(rs, ri);
 264  **/
 265 /* The example above unpacks (approximately) to:
 266  *  int rs_sl_idx = 0, rs_sl_len = smartlist_len(routerstatus_list);
 267  *  int ri_sl_idx, ri_sl_len = smartlist_len(routerinfo_list);
 268  *  int rs_ri_cmp;
 269  *  routerstatus_t *rs;
 270  *  routerinfo_t *ri;
 271  *  for (; ri_sl_idx < ri_sl_len; ++ri_sl_idx) {
 272  *    ri = smartlist_get(routerinfo_list, ri_sl_idx);
 273  *    while (rs_sl_idx < rs_sl_len) {
 274  *      rs = smartlist_get(routerstatus_list, rs_sl_idx);
 275  *      rs_ri_cmp = memcmp(rs->identity_digest, ri->identity_digest, 20);
 276  *      if (rs_ri_cmp > 0) {
 277  *        break;
 278  *      } else if (rs_ri_cmp == 0) {
 279  *        goto matched_ri;
 280  *      } else {
 281  *        ++rs_sl_idx;
 282  *      }
 283  *    }
 284  *    log_info(LD_GENERAL,"No match for %s", ri->nickname);
 285  *    continue;
 286  *   matched_ri: {
 287  *    log_info(LD_GENERAL,"%s matches with routerstatus %p",ri->nickname,rs);
 288  *    }
 289  *  }
 290  */
 291 #define SMARTLIST_FOREACH_JOIN(sl1, type1, var1, sl2, type2, var2,      \
 292                                 cmpexpr, unmatched_var2)                \
 293   STMT_BEGIN                                                            \
 294   int var1 ## _sl_idx = 0, var1 ## _sl_len=(sl1)->num_used;             \
 295   int var2 ## _sl_idx = 0, var2 ## _sl_len=(sl2)->num_used;             \
 296   int var1 ## _ ## var2 ## _cmp;                                        \
 297   type1 var1;                                                           \
 298   type2 var2;                                                           \
 299   for (; var2##_sl_idx < var2##_sl_len; ++var2##_sl_idx) {              \
 300     var2 = (sl2)->list[var2##_sl_idx];                                  \
 301     while (var1##_sl_idx < var1##_sl_len) {                             \
 302       var1 = (sl1)->list[var1##_sl_idx];                                \
 303       var1##_##var2##_cmp = (cmpexpr);                                  \
 304       if (var1##_##var2##_cmp > 0) {                                    \
 305         break;                                                          \
 306       } else if (var1##_##var2##_cmp == 0) {                            \
 307         goto matched_##var2;                                            \
 308       } else {                                                          \
 309         ++var1##_sl_idx;                                                \
 310       }                                                                 \
 311     }                                                                   \
 312     /* Ran out of v1, or no match for var2. */                          \
 313     unmatched_var2;                                                     \
 314     continue;                                                           \
 315     matched_##var2: ;                                                   \
 316
 317 #define SMARTLIST_FOREACH_JOIN_END(var1, var2)  \
 318   }                                             \
 319   STMT_END
 320
 321 #define DECLARE_MAP_FNS(maptype, keytype, prefix)                       \
 322   typedef struct maptype maptype;                                       \
 323   typedef struct prefix##entry_t *prefix##iter_t;                       \
 324   maptype* prefix##new(void);                                           \
 325   void* prefix##set(maptype *map, keytype key, void *val);              \
 326   void* prefix##get(const maptype *map, keytype key);                   \
 327   void* prefix##remove(maptype *map, keytype key);                      \
 328   void prefix##free(maptype *map, void (*free_val)(void*));             \
 329   int prefix##isempty(const maptype *map);                              \
 330   int prefix##size(const maptype *map);                                 \
 331   prefix##iter_t *prefix##iter_init(maptype *map);                      \
 332   prefix##iter_t *prefix##iter_next(maptype *map, prefix##iter_t *iter); \
 333   prefix##iter_t *prefix##iter_next_rmv(maptype *map, prefix##iter_t *iter); \
 334   void prefix##iter_get(prefix##iter_t *iter, keytype *keyp, void **valp); \
 335   int prefix##iter_done(prefix##iter_t *iter);                          \
 336   void prefix##assert_ok(const maptype *map)
 337
 338 /* Map from const char * to void *. Implemented with a hash table. */
 339 DECLARE_MAP_FNS(strmap_t, const char *, strmap_);
 340 /* Map from const char[DIGEST_LEN] to void *. Implemented with a hash table. */
 341 DECLARE_MAP_FNS(digestmap_t, const char *, digestmap_);
 342
 343 #undef DECLARE_MAP_FNS
 344
 345 /** Iterates over the key-value pairs in a map <b>map</b> in order.
 346  * <b>prefix</b> is as for DECLARE_MAP_FNS (i.e., strmap_ or digestmap_).
 347  * The map's keys and values are of type keytype and valtype respectively;
 348  * each iteration assigns them to keyvar and valvar.
 349  *
 350  * Example use:
 351  *   MAP_FOREACH(digestmap_, m, const char *, k, routerinfo_t *, r) {
 352  *     // use k and r
 353  *   } MAP_FOREACH_END.
 354  */
 355 /* Unpacks to, approximately:
 356  * {
 357  *   digestmap_iter_t *k_iter;
 358  *   for (k_iter = digestmap_iter_init(m); !digestmap_iter_done(k_iter);
 359  *        k_iter = digestmap_iter_next(m, k_iter)) {
 360  *     const char *k;
 361  *     void *r_voidp;
 362  *     routerinfo_t *r;
 363  *     digestmap_iter_get(k_iter, &k, &r_voidp);
 364  *     r = r_voidp;
 365  *     // use k and r
 366  *   }
 367  * }
 368  */
 369 #define MAP_FOREACH(prefix, map, keytype, keyvar, valtype, valvar)      \
 370   STMT_BEGIN                                                            \
 371     prefix##iter_t *keyvar##_iter;                                      \
 372     for (keyvar##_iter = prefix##iter_init(map);                        \
 373          !prefix##iter_done(keyvar##_iter);                             \
 374          keyvar##_iter = prefix##iter_next(map, keyvar##_iter)) {       \
 375       keytype keyvar;                                                   \
 376       void *valvar##_voidp;                                             \
 377       valtype valvar;                                                   \
 378       prefix##iter_get(keyvar##_iter, &keyvar, &valvar##_voidp);        \
 379       valvar = valvar##_voidp;
 380
 381 /** As MAP_FOREACH, except allows members to be removed from the map
 382  * during the iteration via MAP_DEL_CURRENT.  Example use:
 383  *
 384  * Example use:
 385  *   MAP_FOREACH(digestmap_, m, const char *, k, routerinfo_t *, r) {
 386  *      if (is_very_old(r))
 387  *       MAP_DEL_CURRENT(k);
 388  *   } MAP_FOREACH_END.
 389  **/
 390 /* Unpacks to, approximately:
 391  * {
 392  *   digestmap_iter_t *k_iter;
 393  *   int k_del=0;
 394  *   for (k_iter = digestmap_iter_init(m); !digestmap_iter_done(k_iter);
 395  *        k_iter = k_del ? digestmap_iter_next(m, k_iter)
 396  *                       : digestmap_iter_next_rmv(m, k_iter)) {
 397  *     const char *k;
 398  *     void *r_voidp;
 399  *     routerinfo_t *r;
 400  *     k_del=0;
 401  *     digestmap_iter_get(k_iter, &k, &r_voidp);
 402  *     r = r_voidp;
 403  *     if (is_very_old(r)) {
 404  *       k_del = 1;
 405  *     }
 406  *   }
 407  * }
 408  */
 409 #define MAP_FOREACH_MODIFY(prefix, map, keytype, keyvar, valtype, valvar) \
 410   STMT_BEGIN                                                            \
 411     prefix##iter_t *keyvar##_iter;                                      \
 412     int keyvar##_del=0;                                                 \
 413     for (keyvar##_iter = prefix##iter_init(map);                        \
 414          !prefix##iter_done(keyvar##_iter);                             \
 415          keyvar##_iter = keyvar##_del ?                                 \
 416            prefix##iter_next_rmv(map, keyvar##_iter) :                  \
 417            prefix##iter_next(map, keyvar##_iter)) {                     \
 418       keytype keyvar;                                                   \
 419       void *valvar##_voidp;                                             \
 420       valtype valvar;                                                   \
 421       keyvar##_del=0;                                                   \
 422       prefix##iter_get(keyvar##_iter, &keyvar, &valvar##_voidp);        \
 423       valvar = valvar##_voidp;
 424
 425 /** Used with MAP_FOREACH_MODIFY to remove the currently-iterated-upon
 426  * member of the map.  */
 427 #define MAP_DEL_CURRENT(keyvar)                   \
 428   STMT_BEGIN                                      \
 429     keyvar##_del = 1;                             \
 430   STMT_END
 431
 432 /** Used to end a MAP_FOREACH() block. */
 433 #define MAP_FOREACH_END } STMT_END ;
 434
 435 /** As MAP_FOREACH, but does not require declaration of prefix or keytype.
 436  * Example use:
 437  *   DIGESTMAP_FOREACH(m, k, routerinfo_t *, r) {
 438  *     // use k and r
 439  *   } DIGESTMAP_FOREACH_END.
 440  */
 441 #define DIGESTMAP_FOREACH(map, keyvar, valtype, valvar)                 \
 442   MAP_FOREACH(digestmap_, map, const char *, keyvar, valtype, valvar)
 443
 444 /** As MAP_FOREACH_MODIFY, but does not require declaration of prefix or
 445  * keytype.
 446  * Example use:
 447  *   DIGESTMAP_FOREACH_MODIFY(m, k, routerinfo_t *, r) {
 448  *      if (is_very_old(r))
 449  *       MAP_DEL_CURRENT(k);
 450  *   } DIGESTMAP_FOREACH_END.
 451  */
 452 #define DIGESTMAP_FOREACH_MODIFY(map, keyvar, valtype, valvar)          \
 453   MAP_FOREACH_MODIFY(digestmap_, map, const char *, keyvar, valtype, valvar)
 454 /** Used to end a DIGESTMAP_FOREACH() block. */
 455 #define DIGESTMAP_FOREACH_END MAP_FOREACH_END
 456
 457 #define STRMAP_FOREACH(map, keyvar, valtype, valvar)                 \
 458   MAP_FOREACH(strmap_, map, const char *, keyvar, valtype, valvar)
 459 #define STRMAP_FOREACH_MODIFY(map, keyvar, valtype, valvar)          \
 460   MAP_FOREACH_MODIFY(strmap_, map, const char *, keyvar, valtype, valvar)
 461 #define STRMAP_FOREACH_END MAP_FOREACH_END
 462
 463 void* strmap_set_lc(strmap_t *map, const char *key, void *val);
 464 void* strmap_get_lc(const strmap_t *map, const char *key);
 465 void* strmap_remove_lc(strmap_t *map, const char *key);
 466
 467 #define DECLARE_TYPED_DIGESTMAP_FNS(prefix, maptype, valtype)           \
 468   typedef struct maptype maptype;                                       \
 469   typedef struct prefix##iter_t prefix##iter_t;                         \
 470   static INLINE maptype* prefix##new(void)                              \
 471   {                                                                     \
 472     return (maptype*)digestmap_new();                                   \
 473   }                                                                     \
 474   static INLINE digestmap_t* prefix##to_digestmap(maptype *map)         \
 475   {                                                                     \
 476     return (digestmap_t*)map;                                           \
 477   }                                                                     \
 478   static INLINE valtype* prefix##get(maptype *map, const char *key)     \
 479   {                                                                     \
 480     return (valtype*)digestmap_get((digestmap_t*)map, key);             \
 481   }                                                                     \
 482   static INLINE valtype* prefix##set(maptype *map, const char *key,     \
 483                                      valtype *val)                      \
 484   {                                                                     \
 485     return (valtype*)digestmap_set((digestmap_t*)map, key, val);        \
 486   }                                                                     \
 487   static INLINE valtype* prefix##remove(maptype *map, const char *key)  \
 488   {                                                                     \
 489     return (valtype*)digestmap_remove((digestmap_t*)map, key);          \
 490   }                                                                     \
 491   static INLINE void prefix##free(maptype *map, void (*free_val)(void*)) \
 492   {                                                                     \
 493     digestmap_free((digestmap_t*)map, free_val);                        \
 494   }                                                                     \
 495   static INLINE int prefix##isempty(maptype *map)                       \
 496   {                                                                     \
 497     return digestmap_isempty((digestmap_t*)map);                        \
 498   }                                                                     \
 499   static INLINE int prefix##size(maptype *map)                          \
 500   {                                                                     \
 501     return digestmap_size((digestmap_t*)map);                           \
 502   }                                                                     \
 503   static INLINE prefix##iter_t *prefix##iter_init(maptype *map)         \
 504   {                                                                     \
 505     return (prefix##iter_t*) digestmap_iter_init((digestmap_t*)map);    \
 506   }                                                                     \
 507   static INLINE prefix##iter_t *prefix##iter_next(maptype *map,         \
 508                                                   prefix##iter_t *iter) \
 509   {                                                                     \
 510     return (prefix##iter_t*) digestmap_iter_next(                       \
 511                        (digestmap_t*)map, (digestmap_iter_t*)iter);     \
 512   }                                                                     \
 513   static INLINE prefix##iter_t *prefix##iter_next_rmv(maptype *map,     \
 514                                                   prefix##iter_t *iter) \
 515   {                                                                     \
 516     return (prefix##iter_t*) digestmap_iter_next_rmv(                   \
 517                        (digestmap_t*)map, (digestmap_iter_t*)iter);     \
 518   }                                                                     \
 519   static INLINE void prefix##iter_get(prefix##iter_t *iter,             \
 520                                       const char **keyp,                \
 521                                       valtype **valp)                   \
 522   {                                                                     \
 523     void *v;                                                            \
 524     digestmap_iter_get((digestmap_iter_t*) iter, keyp, &v);             \
 525     *valp = v;                                                          \
 526   }                                                                     \
 527   static INLINE int prefix##iter_done(prefix##iter_t *iter)             \
 528   {                                                                     \
 529     return digestmap_iter_done((digestmap_iter_t*)iter);                \
 530   }
 531
 532 #if SIZEOF_INT == 4
 533 #define BITARRAY_SHIFT 5
 534 #elif SIZEOF_INT == 8
 535 #define BITARRAY_SHIFT 6
 536 #else
 537 #error "int is neither 4 nor 8 bytes. I can't deal with that."
 538 #endif
 539 #define BITARRAY_MASK ((1u<<BITARRAY_SHIFT)-1)
 540
 541 /** A random-access array of one-bit-wide elements. */
 542 typedef unsigned int bitarray_t;
 543 /** Create a new bit array that can hold <b>n_bits</b> bits. */
 544 static INLINE bitarray_t *
 545 bitarray_init_zero(unsigned int n_bits)
 546 {
 547   /* round up to the next int. */
 548   size_t sz = (n_bits+BITARRAY_MASK) >> BITARRAY_SHIFT;
 549   return tor_malloc_zero(sz*sizeof(unsigned int));
 550 }
 551 /** Expand <b>ba</b> from holding <b>n_bits_old</b> to <b>n_bits_new</b>,
 552  * clearing all new bits.  Returns a possibly changed pointer to the
 553  * bitarray. */
 554 static INLINE bitarray_t *
 555 bitarray_expand(bitarray_t *ba,
 556                 unsigned int n_bits_old, unsigned int n_bits_new)
 557 {
 558   size_t sz_old = (n_bits_old+BITARRAY_MASK) >> BITARRAY_SHIFT;
 559   size_t sz_new = (n_bits_new+BITARRAY_MASK) >> BITARRAY_SHIFT;
 560   char *ptr;
 561   if (sz_new <= sz_old)
 562     return ba;
 563   ptr = tor_realloc(ba, sz_new*sizeof(unsigned int));
 564   /* This memset does nothing to the older excess bytes.  But they were
 565    * already set to 0 by bitarry_init_zero. */
 566   memset(ptr+sz_old*sizeof(unsigned int), 0,
 567          (sz_new-sz_old)*sizeof(unsigned int));
 568   return (bitarray_t*) ptr;
 569 }
 570 /** Free the bit array <b>ba</b>. */
 571 static INLINE void
 572 bitarray_free(bitarray_t *ba)
 573 {
 574   tor_free(ba);
 575 }
 576 /** Set the <b>bit</b>th bit in <b>b</b> to 1. */
 577 static INLINE void
 578 bitarray_set(bitarray_t *b, int bit)
 579 {
 580   b[bit >> BITARRAY_SHIFT] |= (1u << (bit & BITARRAY_MASK));
 581 }
 582 /** Set the <b>bit</b>th bit in <b>b</b> to 0. */
 583 static INLINE void
 584 bitarray_clear(bitarray_t *b, int bit)
 585 {
 586   b[bit >> BITARRAY_SHIFT] &= ~ (1u << (bit & BITARRAY_MASK));
 587 }
 588 /** Return true iff <b>bit</b>th bit in <b>b</b> is nonzero.  NOTE: does
 589  * not necessarily return 1 on true. */
 590 static INLINE unsigned int
 591 bitarray_is_set(bitarray_t *b, int bit)
 592 {
 593   return b[bit >> BITARRAY_SHIFT] & (1u << (bit & BITARRAY_MASK));
 594 }
 595
 596 /** A set of digests, implemented as a Bloom filter. */
 597 typedef struct {
 598   int mask; /* One less than the number of bits in <b>ba</b>; always one less
 599              * than a power of two. */
 600   bitarray_t *ba; /* A bit array to implement the Bloom filter. */
 601 } digestset_t;
 602
 603 #define BIT(n) ((n) & set->mask)
 604 /** Add the digest <b>digest</b> to <b>set</b>. */
 605 static INLINE void
 606 digestset_add(digestset_t *set, const char *digest)
 607 {
 608   const uint32_t *p = (const uint32_t *)digest;
 609   const uint32_t d1 = p[0] + (p[1]>>16);
 610   const uint32_t d2 = p[1] + (p[2]>>16);
 611   const uint32_t d3 = p[2] + (p[3]>>16);
 612   const uint32_t d4 = p[3] + (p[0]>>16);
 613   bitarray_set(set->ba, BIT(d1));
 614   bitarray_set(set->ba, BIT(d2));
 615   bitarray_set(set->ba, BIT(d3));
 616   bitarray_set(set->ba, BIT(d4));
 617 }
 618
 619 /** If <b>digest</b> is in <b>set</b>, return nonzero.  Otherwise,
 620  * <em>probably</em> return zero. */
 621 static INLINE int
 622 digestset_isin(const digestset_t *set, const char *digest)
 623 {
 624   const uint32_t *p = (const uint32_t *)digest;
 625   const uint32_t d1 = p[0] + (p[1]>>16);
 626   const uint32_t d2 = p[1] + (p[2]>>16);
 627   const uint32_t d3 = p[2] + (p[3]>>16);
 628   const uint32_t d4 = p[3] + (p[0]>>16);
 629   return bitarray_is_set(set->ba, BIT(d1)) &&
 630          bitarray_is_set(set->ba, BIT(d2)) &&
 631          bitarray_is_set(set->ba, BIT(d3)) &&
 632          bitarray_is_set(set->ba, BIT(d4));
 633 }
 634 #undef BIT
 635
 636 digestset_t *digestset_new(int max_elements);
 637 void digestset_free(digestset_t* set);
 638
 639 /* These functions, given an <b>array</b> of <b>n_elements</b>, return the
 640  * <b>nth</b> lowest element. <b>nth</b>=0 gives the lowest element;
 641  * <b>n_elements</b>-1 gives the highest; and (<b>n_elements</b>-1) / 2 gives
 642  * the median.  As a side effect, the elements of <b>array</b> are sorted. */
 643 int find_nth_int(int *array, int n_elements, int nth);
 644 time_t find_nth_time(time_t *array, int n_elements, int nth);
 645 double find_nth_double(double *array, int n_elements, int nth);
 646 int32_t find_nth_int32(int32_t *array, int n_elements, int nth);
 647 uint32_t find_nth_uint32(uint32_t *array, int n_elements, int nth);
 648 long find_nth_long(long *array, int n_elements, int nth);
 649 static INLINE int
 650 median_int(int *array, int n_elements)
 651 {
 652   return find_nth_int(array, n_elements, (n_elements-1)/2);
 653 }
 654 static INLINE time_t
 655 median_time(time_t *array, int n_elements)
 656 {
 657   return find_nth_time(array, n_elements, (n_elements-1)/2);
 658 }
 659 static INLINE double
 660 median_double(double *array, int n_elements)
 661 {
 662   return find_nth_double(array, n_elements, (n_elements-1)/2);
 663 }
 664 static INLINE uint32_t
 665 median_uint32(uint32_t *array, int n_elements)
 666 {
 667   return find_nth_uint32(array, n_elements, (n_elements-1)/2);
 668 }
 669 static INLINE int32_t
 670 median_int32(int32_t *array, int n_elements)
 671 {
 672   return find_nth_int32(array, n_elements, (n_elements-1)/2);
 673 }
 674 static INLINE long
 675 median_long(long *array, int n_elements)
 676 {
 677   return find_nth_long(array, n_elements, (n_elements-1)/2);
 678 }
 679
 680 #endif
 681