src/common/container.h

   1 /* Copyright (c) 2003-2004, Roger Dingledine
   2  * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
   3  * Copyright (c) 2007-2009, 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_uniq(smartlist_t *sl,
  97                     int (*compare)(const void **a, const void **b),
  98                     void (*free_fn)(void *elt));
  99 void smartlist_sort_strings(smartlist_t *sl);
 100 void smartlist_sort_digests(smartlist_t *sl);
 101 void smartlist_uniq_strings(smartlist_t *sl);
 102 void smartlist_uniq_digests(smartlist_t *sl);
 103 void *smartlist_bsearch(smartlist_t *sl, const void *key,
 104                         int (*compare)(const void *key, const void **member))
 105   ATTR_PURE;
 106 int smartlist_bsearch_idx(const smartlist_t *sl, const void *key,
 107                           int (*compare)(const void *key, const void **member),
 108                           int *found_out);
 109
 110 void smartlist_pqueue_add(smartlist_t *sl,
 111                           int (*compare)(const void *a, const void *b),
 112                           void *item);
 113 void *smartlist_pqueue_pop(smartlist_t *sl,
 114                            int (*compare)(const void *a, const void *b));
 115 void smartlist_pqueue_assert_ok(smartlist_t *sl,
 116                                 int (*compare)(const void *a, const void *b));
 117
 118 #define SPLIT_SKIP_SPACE   0x01
 119 #define SPLIT_IGNORE_BLANK 0x02
 120 #define SPLIT_STRIP_SPACE  0x04
 121 int smartlist_split_string(smartlist_t *sl, const char *str, const char *sep,
 122                            int flags, int max);
 123 char *smartlist_join_strings(smartlist_t *sl, const char *join, int terminate,
 124                              size_t *len_out) ATTR_MALLOC;
 125 char *smartlist_join_strings2(smartlist_t *sl, const char *join,
 126                               size_t join_len, int terminate, size_t *len_out)
 127   ATTR_MALLOC;
 128
 129 /** Iterate over the items in a smartlist <b>sl</b>, in order.  For each item,
 130  * assign it to a new local variable of type <b>type</b> named <b>var</b>, and
 131  * execute the statement <b>cmd</b>.  Inside the loop, the loop index can
 132  * be accessed as <b>var</b>_sl_idx and the length of the list can be accessed
 133  * as <b>var</b>_sl_len.
 134  *
 135  * NOTE: Do not change the length of the list while the loop is in progress,
 136  * unless you adjust the _sl_len variable correspondingly.  See second example
 137  * below.
 138  *
 139  * Example use:
 140  * <pre>
 141  *   smartlist_t *list = smartlist_split("A:B:C", ":", 0, 0);
 142  *   SMARTLIST_FOREACH(list, char *, cp,
 143  *   {
 144  *     printf("%d: %s\n", cp_sl_idx, cp);
 145  *     tor_free(cp);
 146  *   });
 147  *   smartlist_free(list);
 148  * </pre>
 149  *
 150  * Example use (advanced):
 151  * <pre>
 152  *   SMARTLIST_FOREACH(list, char *, cp,
 153  *   {
 154  *     if (!strcmp(cp, "junk")) {
 155  *       tor_free(cp);
 156  *       SMARTLIST_DEL_CURRENT(list, cp);
 157  *     }
 158  *   });
 159  * </pre>
 160  */
 161 /* Note: these macros use token pasting, and reach into smartlist internals.
 162  * This can make them a little daunting. Here's the approximate unpacking of
 163  * the above examples, for entertainment value:
 164  *
 165  * <pre>
 166  * smartlist_t *list = smartlist_split("A:B:C", ":", 0, 0);
 167  * {
 168  *   int cp_sl_idx, cp_sl_len = smartlist_len(list);
 169  *   char *cp;
 170  *   for (cp_sl_idx = 0; cp_sl_idx < cp_sl_len; ++cp_sl_idx) {
 171  *     cp = smartlist_get(list, cp_sl_idx);
 172  *     printf("%d: %s\n", cp_sl_idx, cp);
 173  *     tor_free(cp);
 174  *   }
 175  * }
 176  * smartlist_free(list);
 177  * </pre>
 178  *
 179  * <pre>
 180  * {
 181  *   int cp_sl_idx, cp_sl_len = smartlist_len(list);
 182  *   char *cp;
 183  *   for (cp_sl_idx = 0; cp_sl_idx < cp_sl_len; ++cp_sl_idx) {
 184  *     cp = smartlist_get(list, cp_sl_idx);
 185  *     if (!strcmp(cp, "junk")) {
 186  *       tor_free(cp);
 187  *       smartlist_del(list, cp_sl_idx);
 188  *       --cp_sl_idx;
 189  *       --cp_sl_len;
 190  *     }
 191  *   }
 192  * }
 193  * </pre>
 194  */
 195 #define SMARTLIST_FOREACH_BEGIN(sl, type, var)  \
 196   STMT_BEGIN                                                    \
 197     int var ## _sl_idx, var ## _sl_len=(sl)->num_used;          \
 198     type var;                                                   \
 199     for (var ## _sl_idx = 0; var ## _sl_idx < var ## _sl_len;   \
 200          ++var ## _sl_idx) {                                    \
 201       var = (sl)->list[var ## _sl_idx];
 202
 203 #define SMARTLIST_FOREACH_END(var)              \
 204     var = NULL;                                 \
 205   } STMT_END
 206
 207 #define SMARTLIST_FOREACH(sl, type, var, cmd)                   \
 208   SMARTLIST_FOREACH_BEGIN(sl,type,var) {                        \
 209     cmd;                                                        \
 210   } SMARTLIST_FOREACH_END(var)
 211
 212 /** Helper: While in a SMARTLIST_FOREACH loop over the list <b>sl</b> indexed
 213  * with the variable <b>var</b>, remove the current element in a way that
 214  * won't confuse the loop. */
 215 #define SMARTLIST_DEL_CURRENT(sl, var)          \
 216   STMT_BEGIN                                    \
 217     smartlist_del(sl, var ## _sl_idx);          \
 218     --var ## _sl_idx;                           \
 219     --var ## _sl_len;                           \
 220   STMT_END
 221
 222 /** Helper: While in a SMARTLIST_FOREACH loop over the list <b>sl</b> indexed
 223  * with the variable <b>var</b>, replace the current element with <b>val</b>.
 224  * Does not deallocate the current value of <b>var</b>.
 225  */
 226 #define SMARTLIST_REPLACE_CURRENT(sl, var, val) \
 227   STMT_BEGIN                                    \
 228     smartlist_set(sl, var ## _sl_idx, val);     \
 229   STMT_END
 230
 231 /* Helper: Given two lists of items, possibly of different types, such that
 232  * both lists are sorted on some common field (as determined by a comparison
 233  * expression <b>cmpexpr</b>), and such that one list (<b>sl1</b>) has no
 234  * duplicates on the common field, loop through the lists in lockstep, and
 235  * execute <b>unmatched_var2</b> on items in var2 that do not appear in
 236  * var1.
 237  *
 238  * WARNING: It isn't safe to add remove elements from either list while the
 239  * loop is in progress.
 240  *
 241  * Example use:
 242  *  SMARTLIST_FOREACH_JOIN(routerstatus_list, routerstatus_t *, rs,
 243  *                     routerinfo_list, routerinfo_t *, ri,
 244  *                     memcmp(rs->identity_digest, ri->identity_digest, 20),
 245  *                     log_info(LD_GENERAL,"No match for %s", ri->nickname)) {
 246  *    log_info(LD_GENERAL, "%s matches routerstatus %p", ri->nickname, rs);
 247  * } SMARTLIST_FOREACH_JOIN_END(rs, ri);
 248  **/
 249 /* The example above unpacks (approximately) to:
 250  *  int rs_sl_idx = 0, rs_sl_len = smartlist_len(routerstatus_list);
 251  *  int ri_sl_idx, ri_sl_len = smartlist_len(routerinfo_list);
 252  *  int rs_ri_cmp;
 253  *  routerstatus_t *rs;
 254  *  routerinfo_t *ri;
 255  *  for (; ri_sl_idx < ri_sl_len; ++ri_sl_idx) {
 256  *    ri = smartlist_get(routerinfo_list, ri_sl_idx);
 257  *    while (rs_sl_idx < rs_sl_len) {
 258  *      rs = smartlist_get(routerstatus_list, rs_sl_idx);
 259  *      rs_ri_cmp = memcmp(rs->identity_digest, ri->identity_digest, 20);
 260  *      if (rs_ri_cmp > 0) {
 261  *        break;
 262  *      } else if (rs_ri_cmp == 0) {
 263  *        goto matched_ri;
 264  *      } else {
 265  *        ++rs_sl_idx;
 266  *      }
 267  *    }
 268  *    log_info(LD_GENERAL,"No match for %s", ri->nickname);
 269  *    continue;
 270  *   matched_ri: {
 271  *    log_info(LD_GENERAL,"%s matches with routerstatus %p",ri->nickname,rs);
 272  *    }
 273  *  }
 274  */
 275 #define SMARTLIST_FOREACH_JOIN(sl1, type1, var1, sl2, type2, var2,      \
 276                                 cmpexpr, unmatched_var2)                \
 277   STMT_BEGIN                                                            \
 278   int var1 ## _sl_idx = 0, var1 ## _sl_len=(sl1)->num_used;             \
 279   int var2 ## _sl_idx = 0, var2 ## _sl_len=(sl2)->num_used;             \
 280   int var1 ## _ ## var2 ## _cmp;                                        \
 281   type1 var1;                                                           \
 282   type2 var2;                                                           \
 283   for (; var2##_sl_idx < var2##_sl_len; ++var2##_sl_idx) {              \
 284     var2 = (sl2)->list[var2##_sl_idx];                                  \
 285     while (var1##_sl_idx < var1##_sl_len) {                             \
 286       var1 = (sl1)->list[var1##_sl_idx];                                \
 287       var1##_##var2##_cmp = (cmpexpr);                                  \
 288       if (var1##_##var2##_cmp > 0) {                                    \
 289         break;                                                          \
 290       } else if (var1##_##var2##_cmp == 0) {                            \
 291         goto matched_##var2;                                            \
 292       } else {                                                          \
 293         ++var1##_sl_idx;                                                \
 294       }                                                                 \
 295     }                                                                   \
 296     /* Ran out of v1, or no match for var2. */                          \
 297     unmatched_var2;                                                     \
 298     continue;                                                           \
 299     matched_##var2: ;                                                   \
 300
 301 #define SMARTLIST_FOREACH_JOIN_END(var1, var2)  \
 302   }                                             \
 303   STMT_END
 304
 305 #define DECLARE_MAP_FNS(maptype, keytype, prefix)                       \
 306   typedef struct maptype maptype;                                       \
 307   typedef struct prefix##entry_t *prefix##iter_t;                       \
 308   maptype* prefix##new(void);                                           \
 309   void* prefix##set(maptype *map, keytype key, void *val);              \
 310   void* prefix##get(const maptype *map, keytype key);                   \
 311   void* prefix##remove(maptype *map, keytype key);                      \
 312   void prefix##free(maptype *map, void (*free_val)(void*));             \
 313   int prefix##isempty(const maptype *map);                              \
 314   int prefix##size(const maptype *map);                                 \
 315   prefix##iter_t *prefix##iter_init(maptype *map);                      \
 316   prefix##iter_t *prefix##iter_next(maptype *map, prefix##iter_t *iter); \
 317   prefix##iter_t *prefix##iter_next_rmv(maptype *map, prefix##iter_t *iter); \
 318   void prefix##iter_get(prefix##iter_t *iter, keytype *keyp, void **valp); \
 319   int prefix##iter_done(prefix##iter_t *iter);                          \
 320   void prefix##assert_ok(const maptype *map)
 321
 322 /* Map from const char * to void *. Implemented with a hash table. */
 323 DECLARE_MAP_FNS(strmap_t, const char *, strmap_);
 324 /* Map from const char[DIGEST_LEN] to void *. Implemented with a hash table. */
 325 DECLARE_MAP_FNS(digestmap_t, const char *, digestmap_);
 326
 327 #undef DECLARE_MAP_FNS
 328
 329 /** Iterates over the key-value pairs in a map <b>map</b> in order.
 330  * <b>prefix</b> is as for DECLARE_MAP_FNS (i.e., strmap_ or digestmap_).
 331  * The map's keys and values are of type keytype and valtype respectively;
 332  * each iteration assigns them to keyvar and valvar.
 333  *
 334  * Example use:
 335  *   MAP_FOREACH(digestmap_, m, const char *, k, routerinfo_t *, r) {
 336  *     // use k and r
 337  *   } MAP_FOREACH_END.
 338  */
 339 /* Unpacks to, approximately:
 340  * {
 341  *   digestmap_iter_t *k_iter;
 342  *   for (k_iter = digestmap_iter_init(m); !digestmap_iter_done(k_iter);
 343  *        k_iter = digestmap_iter_next(m, k_iter)) {
 344  *     const char *k;
 345  *     void *r_voidp;
 346  *     routerinfo_t *r;
 347  *     digestmap_iter_get(k_iter, &k, &r_voidp);
 348  *     r = r_voidp;
 349  *     // use k and r
 350  *   }
 351  * }
 352  */
 353 #define MAP_FOREACH(prefix, map, keytype, keyvar, valtype, valvar)      \
 354   STMT_BEGIN                                                            \
 355     prefix##iter_t *keyvar##_iter;                                      \
 356     for (keyvar##_iter = prefix##iter_init(map);                        \
 357          !prefix##iter_done(keyvar##_iter);                             \
 358          keyvar##_iter = prefix##iter_next(map, keyvar##_iter)) {       \
 359       keytype keyvar;                                                   \
 360       void *valvar##_voidp;                                             \
 361       valtype valvar;                                                   \
 362       prefix##iter_get(keyvar##_iter, &keyvar, &valvar##_voidp);        \
 363       valvar = valvar##_voidp;
 364
 365 /** As MAP_FOREACH, except allows members to be removed from the map
 366  * during the iteration via MAP_DEL_CURRENT.  Example use:
 367  *
 368  * Example use:
 369  *   MAP_FOREACH(digestmap_, m, const char *, k, routerinfo_t *, r) {
 370  *      if (is_very_old(r))
 371  *       MAP_DEL_CURRENT(k);
 372  *   } MAP_FOREACH_END.
 373  **/
 374 /* Unpacks to, approximately:
 375  * {
 376  *   digestmap_iter_t *k_iter;
 377  *   int k_del=0;
 378  *   for (k_iter = digestmap_iter_init(m); !digestmap_iter_done(k_iter);
 379  *        k_iter = k_del ? digestmap_iter_next(m, k_iter)
 380  *                       : digestmap_iter_next_rmv(m, k_iter)) {
 381  *     const char *k;
 382  *     void *r_voidp;
 383  *     routerinfo_t *r;
 384  *     k_del=0;
 385  *     digestmap_iter_get(k_iter, &k, &r_voidp);
 386  *     r = r_voidp;
 387  *     if (is_very_old(r)) {
 388  *       k_del = 1;
 389  *     }
 390  *   }
 391  * }
 392  */
 393 #define MAP_FOREACH_MODIFY(prefix, map, keytype, keyvar, valtype, valvar) \
 394   STMT_BEGIN                                                            \
 395     prefix##iter_t *keyvar##_iter;                                      \
 396     int keyvar##_del=0;                                                 \
 397     for (keyvar##_iter = prefix##iter_init(map);                        \
 398          !prefix##iter_done(keyvar##_iter);                             \
 399          keyvar##_iter = keyvar##_del ?                                 \
 400            prefix##iter_next_rmv(map, keyvar##_iter) :                  \
 401            prefix##iter_next(map, keyvar##_iter)) {                     \
 402       keytype keyvar;                                                   \
 403       void *valvar##_voidp;                                             \
 404       valtype valvar;                                                   \
 405       keyvar##_del=0;                                                   \
 406       prefix##iter_get(keyvar##_iter, &keyvar, &valvar##_voidp);        \
 407       valvar = valvar##_voidp;
 408
 409 /** Used with MAP_FOREACH_MODIFY to remove the currently-iterated-upon
 410  * member of the map.  */
 411 #define MAP_DEL_CURRENT(keyvar)                   \
 412   STMT_BEGIN                                      \
 413     keyvar##_del = 1;                             \
 414   STMT_END
 415
 416 /** Used to end a MAP_FOREACH() block. */
 417 #define MAP_FOREACH_END } STMT_END ;
 418
 419 /** As MAP_FOREACH, but does not require declaration of prefix or keytype.
 420  * Example use:
 421  *   DIGESTMAP_FOREACH(m, k, routerinfo_t *, r) {
 422  *     // use k and r
 423  *   } DIGESTMAP_FOREACH_END.
 424  */
 425 #define DIGESTMAP_FOREACH(map, keyvar, valtype, valvar)                 \
 426   MAP_FOREACH(digestmap_, map, const char *, keyvar, valtype, valvar)
 427
 428 /** As MAP_FOREACH_MODIFY, but does not require declaration of prefix or
 429  * keytype.
 430  * Example use:
 431  *   DIGESTMAP_FOREACH_MODIFY(m, k, routerinfo_t *, r) {
 432  *      if (is_very_old(r))
 433  *       MAP_DEL_CURRENT(k);
 434  *   } DIGESTMAP_FOREACH_END.
 435  */
 436 #define DIGESTMAP_FOREACH_MODIFY(map, keyvar, valtype, valvar)          \
 437   MAP_FOREACH_MODIFY(digestmap_, map, const char *, keyvar, valtype, valvar)
 438 /** Used to end a DIGESTMAP_FOREACH() block. */
 439 #define DIGESTMAP_FOREACH_END MAP_FOREACH_END
 440
 441 #define STRMAP_FOREACH(map, keyvar, valtype, valvar)                 \
 442   MAP_FOREACH(strmap_, map, const char *, keyvar, valtype, valvar)
 443 #define STRMAP_FOREACH_MODIFY(map, keyvar, valtype, valvar)          \
 444   MAP_FOREACH_MODIFY(strmap_, map, const char *, keyvar, valtype, valvar)
 445 #define STRMAP_FOREACH_END MAP_FOREACH_END
 446
 447 void* strmap_set_lc(strmap_t *map, const char *key, void *val);
 448 void* strmap_get_lc(const strmap_t *map, const char *key);
 449 void* strmap_remove_lc(strmap_t *map, const char *key);
 450
 451 #define DECLARE_TYPED_DIGESTMAP_FNS(prefix, maptype, valtype)           \
 452   typedef struct maptype maptype;                                       \
 453   typedef struct prefix##iter_t prefix##iter_t;                         \
 454   static INLINE maptype* prefix##new(void)                              \
 455   {                                                                     \
 456     return (maptype*)digestmap_new();                                   \
 457   }                                                                     \
 458   static INLINE digestmap_t* prefix##to_digestmap(maptype *map)         \
 459   {                                                                     \
 460     return (digestmap_t*)map;                                           \
 461   }                                                                     \
 462   static INLINE valtype* prefix##get(maptype *map, const char *key)     \
 463   {                                                                     \
 464     return (valtype*)digestmap_get((digestmap_t*)map, key);             \
 465   }                                                                     \
 466   static INLINE valtype* prefix##set(maptype *map, const char *key,     \
 467                                      valtype *val)                      \
 468   {                                                                     \
 469     return (valtype*)digestmap_set((digestmap_t*)map, key, val);        \
 470   }                                                                     \
 471   static INLINE valtype* prefix##remove(maptype *map, const char *key)  \
 472   {                                                                     \
 473     return (valtype*)digestmap_remove((digestmap_t*)map, key);          \
 474   }                                                                     \
 475   static INLINE void prefix##free(maptype *map, void (*free_val)(void*)) \
 476   {                                                                     \
 477     digestmap_free((digestmap_t*)map, free_val);                        \
 478   }                                                                     \
 479   static INLINE int prefix##isempty(maptype *map)                       \
 480   {                                                                     \
 481     return digestmap_isempty((digestmap_t*)map);                        \
 482   }                                                                     \
 483   static INLINE int prefix##size(maptype *map)                          \
 484   {                                                                     \
 485     return digestmap_size((digestmap_t*)map);                           \
 486   }                                                                     \
 487   static INLINE prefix##iter_t *prefix##iter_init(maptype *map)         \
 488   {                                                                     \
 489     return (prefix##iter_t*) digestmap_iter_init((digestmap_t*)map);    \
 490   }                                                                     \
 491   static INLINE prefix##iter_t *prefix##iter_next(maptype *map,         \
 492                                                   prefix##iter_t *iter) \
 493   {                                                                     \
 494     return (prefix##iter_t*) digestmap_iter_next(                       \
 495                        (digestmap_t*)map, (digestmap_iter_t*)iter);     \
 496   }                                                                     \
 497   static INLINE prefix##iter_t *prefix##iter_next_rmv(maptype *map,     \
 498                                                   prefix##iter_t *iter) \
 499   {                                                                     \
 500     return (prefix##iter_t*) digestmap_iter_next_rmv(                   \
 501                        (digestmap_t*)map, (digestmap_iter_t*)iter);     \
 502   }                                                                     \
 503   static INLINE void prefix##iter_get(prefix##iter_t *iter,             \
 504                                       const char **keyp,                \
 505                                       valtype **valp)                   \
 506   {                                                                     \
 507     void *v;                                                            \
 508     digestmap_iter_get((digestmap_iter_t*) iter, keyp, &v);             \
 509     *valp = v;                                                          \
 510   }                                                                     \
 511   static INLINE int prefix##iter_done(prefix##iter_t *iter)             \
 512   {                                                                     \
 513     return digestmap_iter_done((digestmap_iter_t*)iter);                \
 514   }
 515
 516 #if SIZEOF_INT == 4
 517 #define BITARRAY_SHIFT 5
 518 #elif SIZEOF_INT == 8
 519 #define BITARRAY_SHIFT 6
 520 #else
 521 #error "int is neither 4 nor 8 bytes. I can't deal with that."
 522 #endif
 523 #define BITARRAY_MASK ((1u<<BITARRAY_SHIFT)-1)
 524
 525 /** A random-access array of one-bit-wide elements. */
 526 typedef unsigned int bitarray_t;
 527 /** Create a new bit array that can hold <b>n_bits</b> bits. */
 528 static INLINE bitarray_t *
 529 bitarray_init_zero(unsigned int n_bits)
 530 {
 531   /* round up to the next int. */
 532   size_t sz = (n_bits+BITARRAY_MASK) >> BITARRAY_SHIFT;
 533   return tor_malloc_zero(sz*sizeof(unsigned int));
 534 }
 535 /** Expand <b>ba</b> from holding <b>n_bits_old</b> to <b>n_bits_new</b>,
 536  * clearing all new bits.  Returns a possibly changed pointer to the
 537  * bitarray. */
 538 static INLINE bitarray_t *
 539 bitarray_expand(bitarray_t *ba,
 540                 unsigned int n_bits_old, unsigned int n_bits_new)
 541 {
 542   size_t sz_old = (n_bits_old+BITARRAY_MASK) >> BITARRAY_SHIFT;
 543   size_t sz_new = (n_bits_new+BITARRAY_MASK) >> BITARRAY_SHIFT;
 544   char *ptr;
 545   if (sz_new <= sz_old)
 546     return ba;
 547   ptr = tor_realloc(ba, sz_new*sizeof(unsigned int));
 548   /* This memset does nothing to the older excess bytes.  But they were
 549    * already set to 0 by bitarry_init_zero. */
 550   memset(ptr+sz_old*sizeof(unsigned int), 0,
 551          (sz_new-sz_old)*sizeof(unsigned int));
 552   return (bitarray_t*) ptr;
 553 }
 554 /** Free the bit array <b>ba</b>. */
 555 static INLINE void
 556 bitarray_free(bitarray_t *ba)
 557 {
 558   tor_free(ba);
 559 }
 560 /** Set the <b>bit</b>th bit in <b>b</b> to 1. */
 561 static INLINE void
 562 bitarray_set(bitarray_t *b, int bit)
 563 {
 564   b[bit >> BITARRAY_SHIFT] |= (1u << (bit & BITARRAY_MASK));
 565 }
 566 /** Set the <b>bit</b>th bit in <b>b</b> to 0. */
 567 static INLINE void
 568 bitarray_clear(bitarray_t *b, int bit)
 569 {
 570   b[bit >> BITARRAY_SHIFT] &= ~ (1u << (bit & BITARRAY_MASK));
 571 }
 572 /** Return true iff <b>bit</b>th bit in <b>b</b> is nonzero.  NOTE: does
 573  * not necessarily return 1 on true. */
 574 static INLINE unsigned int
 575 bitarray_is_set(bitarray_t *b, int bit)
 576 {
 577   return b[bit >> BITARRAY_SHIFT] & (1u << (bit & BITARRAY_MASK));
 578 }
 579
 580 /** A set of digests, implemented as a Bloom filter. */
 581 typedef struct {
 582   int mask; /* One less than the number of bits in <b>ba</b>; always one less
 583              * than a power of two. */
 584   bitarray_t *ba; /* A bit array to implement the Bloom filter. */
 585 } digestset_t;
 586
 587 #define BIT(n) ((n) & set->mask)
 588 /** Add the digest <b>digest</b> to <b>set</b>. */
 589 static INLINE void
 590 digestset_add(digestset_t *set, const char *digest)
 591 {
 592   const uint32_t *p = (const uint32_t *)digest;
 593   const uint32_t d1 = p[0] + (p[1]>>16);
 594   const uint32_t d2 = p[1] + (p[2]>>16);
 595   const uint32_t d3 = p[2] + (p[3]>>16);
 596   const uint32_t d4 = p[3] + (p[0]>>16);
 597   bitarray_set(set->ba, BIT(d1));
 598   bitarray_set(set->ba, BIT(d2));
 599   bitarray_set(set->ba, BIT(d3));
 600   bitarray_set(set->ba, BIT(d4));
 601 }
 602
 603 /** If <b>digest</b> is in <b>set</b>, return nonzero.  Otherwise,
 604  * <em>probably</em> return zero. */
 605 static INLINE int
 606 digestset_isin(const 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   return bitarray_is_set(set->ba, BIT(d1)) &&
 614          bitarray_is_set(set->ba, BIT(d2)) &&
 615          bitarray_is_set(set->ba, BIT(d3)) &&
 616          bitarray_is_set(set->ba, BIT(d4));
 617 }
 618 #undef BIT
 619
 620 digestset_t *digestset_new(int max_elements);
 621 void digestset_free(digestset_t* set);
 622
 623 /* These functions, given an <b>array</b> of <b>n_elements</b>, return the
 624  * <b>nth</b> lowest element. <b>nth</b>=0 gives the lowest element;
 625  * <b>n_elements</b>-1 gives the highest; and (<b>n_elements</b>-1) / 2 gives
 626  * the median.  As a side effect, the elements of <b>array</b> are sorted. */
 627 int find_nth_int(int *array, int n_elements, int nth);
 628 time_t find_nth_time(time_t *array, int n_elements, int nth);
 629 double find_nth_double(double *array, int n_elements, int nth);
 630 uint32_t find_nth_uint32(uint32_t *array, int n_elements, int nth);
 631 long find_nth_long(long *array, int n_elements, int nth);
 632 static INLINE int
 633 median_int(int *array, int n_elements)
 634 {
 635   return find_nth_int(array, n_elements, (n_elements-1)/2);
 636 }
 637 static INLINE time_t
 638 median_time(time_t *array, int n_elements)
 639 {
 640   return find_nth_time(array, n_elements, (n_elements-1)/2);
 641 }
 642 static INLINE double
 643 median_double(double *array, int n_elements)
 644 {
 645   return find_nth_double(array, n_elements, (n_elements-1)/2);
 646 }
 647 static INLINE uint32_t
 648 median_uint32(uint32_t *array, int n_elements)
 649 {
 650   return find_nth_uint32(array, n_elements, (n_elements-1)/2);
 651 }
 652 static INLINE long
 653 median_long(long *array, int n_elements)
 654 {
 655   return find_nth_long(array, n_elements, (n_elements-1)/2);
 656 }
 657
 658 #endif
 659