Refactor container into a library.

1 files changed, 750 insertions, 0 deletions

diff --git a/src/lib/container/container.h b/src/lib/container/container.h
new file mode 100644
index 0000000000..c45bfc359b
--- /dev/null
+++ b/src/lib/container/container.h
@@ -0,0 +1,750 @@
+/* Copyright (c) 2003-2004, Roger Dingledine
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#ifndef TOR_CONTAINER_H
+#define TOR_CONTAINER_H
+
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "lib/cc/compat_compiler.h"
+#include "lib/cc/torint.h"
+#include "lib/testsupport/testsupport.h"
+#include "lib/malloc/util_malloc.h"
+#include "common/util_bug.h"
+#include "siphash.h"
+
+/** A resizeable list of pointers, with associated helpful functionality.
+ *
+ * The members of this struct are exposed only so that macros and inlines can
+ * use them; all access to smartlist internals should go through the functions
+ * and macros defined here.
+ **/
+typedef struct smartlist_t {
+  /** @{ */
+  /** <b>list</b> has enough capacity to store exactly <b>capacity</b> elements
+   * before it needs to be resized.  Only the first <b>num_used</b> (\<=
+   * capacity) elements point to valid data.
+   */
+  void **list;
+  int num_used;
+  int capacity;
+  /** @} */
+} smartlist_t;
+
+MOCK_DECL(smartlist_t *, smartlist_new, (void));
+MOCK_DECL(void, smartlist_free_, (smartlist_t *sl));
+#define smartlist_free(sl) FREE_AND_NULL(smartlist_t, smartlist_free_, (sl))
+
+void smartlist_clear(smartlist_t *sl);
+void smartlist_add(smartlist_t *sl, void *element);
+void smartlist_add_all(smartlist_t *sl, const smartlist_t *s2);
+void smartlist_add_strdup(struct smartlist_t *sl, const char *string);
+void smartlist_remove(smartlist_t *sl, const void *element);
+void smartlist_remove_keeporder(smartlist_t *sl, const void *element);
+void *smartlist_pop_last(smartlist_t *sl);
+void smartlist_reverse(smartlist_t *sl);
+void smartlist_string_remove(smartlist_t *sl, const char *element);
+int smartlist_contains(const smartlist_t *sl, const void *element);
+int smartlist_contains_string(const smartlist_t *sl, const char *element);
+int smartlist_pos(const smartlist_t *sl, const void *element);
+int smartlist_string_pos(const smartlist_t *, const char *elt);
+int smartlist_contains_string_case(const smartlist_t *sl, const char *element);
+int smartlist_contains_int_as_string(const smartlist_t *sl, int num);
+int smartlist_strings_eq(const smartlist_t *sl1, const smartlist_t *sl2);
+int smartlist_contains_digest(const smartlist_t *sl, const char *element);
+int smartlist_ints_eq(const smartlist_t *sl1, const smartlist_t *sl2);
+int smartlist_overlap(const smartlist_t *sl1, const smartlist_t *sl2);
+void smartlist_intersect(smartlist_t *sl1, const smartlist_t *sl2);
+void smartlist_subtract(smartlist_t *sl1, const smartlist_t *sl2);
+
+/* smartlist_choose() is defined in crypto.[ch] */
+#ifdef DEBUG_SMARTLIST
+/** Return the number of items in sl.
+ */
+static inline int smartlist_len(const smartlist_t *sl);
+static inline int smartlist_len(const smartlist_t *sl) {
+  tor_assert(sl);
+  return (sl)->num_used;
+}
+/** Return the <b>idx</b>th element of sl.
+ */
+static inline void *smartlist_get(const smartlist_t *sl, int idx);
+static inline void *smartlist_get(const smartlist_t *sl, int idx) {
+  tor_assert(sl);
+  tor_assert(idx>=0);
+  tor_assert(sl->num_used > idx);
+  return sl->list[idx];
+}
+static inline void smartlist_set(smartlist_t *sl, int idx, void *val) {
+  tor_assert(sl);
+  tor_assert(idx>=0);
+  tor_assert(sl->num_used > idx);
+  sl->list[idx] = val;
+}
+#else /* !(defined(DEBUG_SMARTLIST)) */
+#define smartlist_len(sl) ((sl)->num_used)
+#define smartlist_get(sl, idx) ((sl)->list[idx])
+#define smartlist_set(sl, idx, val) ((sl)->list[idx] = (val))
+#endif /* defined(DEBUG_SMARTLIST) */
+
+/** Exchange the elements at indices <b>idx1</b> and <b>idx2</b> of the
+ * smartlist <b>sl</b>. */
+static inline void smartlist_swap(smartlist_t *sl, int idx1, int idx2)
+{
+  if (idx1 != idx2) {
+    void *elt = smartlist_get(sl, idx1);
+    smartlist_set(sl, idx1, smartlist_get(sl, idx2));
+    smartlist_set(sl, idx2, elt);
+  }
+}
+
+void smartlist_del(smartlist_t *sl, int idx);
+void smartlist_del_keeporder(smartlist_t *sl, int idx);
+void smartlist_insert(smartlist_t *sl, int idx, void *val);
+void smartlist_sort(smartlist_t *sl,
+                    int (*compare)(const void **a, const void **b));
+void *smartlist_get_most_frequent_(const smartlist_t *sl,
+                    int (*compare)(const void **a, const void **b),
+                    int *count_out);
+#define smartlist_get_most_frequent(sl, compare) \
+  smartlist_get_most_frequent_((sl), (compare), NULL)
+void smartlist_uniq(smartlist_t *sl,
+                    int (*compare)(const void **a, const void **b),
+                    void (*free_fn)(void *elt));
+
+void smartlist_sort_strings(smartlist_t *sl);
+void smartlist_sort_digests(smartlist_t *sl);
+void smartlist_sort_digests256(smartlist_t *sl);
+void smartlist_sort_pointers(smartlist_t *sl);
+
+const char *smartlist_get_most_frequent_string(smartlist_t *sl);
+const char *smartlist_get_most_frequent_string_(smartlist_t *sl,
+                                                int *count_out);
+const uint8_t *smartlist_get_most_frequent_digest256(smartlist_t *sl);
+
+void smartlist_uniq_strings(smartlist_t *sl);
+void smartlist_uniq_digests(smartlist_t *sl);
+void smartlist_uniq_digests256(smartlist_t *sl);
+void *smartlist_bsearch(smartlist_t *sl, const void *key,
+                        int (*compare)(const void *key, const void **member));
+int smartlist_bsearch_idx(const smartlist_t *sl, const void *key,
+                          int (*compare)(const void *key, const void **member),
+                          int *found_out);
+
+void smartlist_pqueue_add(smartlist_t *sl,
+                          int (*compare)(const void *a, const void *b),
+                          int idx_field_offset,
+                          void *item);
+void *smartlist_pqueue_pop(smartlist_t *sl,
+                           int (*compare)(const void *a, const void *b),
+                           int idx_field_offset);
+void smartlist_pqueue_remove(smartlist_t *sl,
+                             int (*compare)(const void *a, const void *b),
+                             int idx_field_offset,
+                             void *item);
+void smartlist_pqueue_assert_ok(smartlist_t *sl,
+                                int (*compare)(const void *a, const void *b),
+                                int idx_field_offset);
+
+#define SPLIT_SKIP_SPACE   0x01
+#define SPLIT_IGNORE_BLANK 0x02
+#define SPLIT_STRIP_SPACE  0x04
+int smartlist_split_string(smartlist_t *sl, const char *str, const char *sep,
+                           int flags, int max);
+char *smartlist_join_strings(smartlist_t *sl, const char *join, int terminate,
+                             size_t *len_out) ATTR_MALLOC;
+char *smartlist_join_strings2(smartlist_t *sl, const char *join,
+                              size_t join_len, int terminate, size_t *len_out)
+  ATTR_MALLOC;
+
+/** Iterate over the items in a smartlist <b>sl</b>, in order.  For each item,
+ * assign it to a new local variable of type <b>type</b> named <b>var</b>, and
+ * execute the statements inside the loop body.  Inside the loop, the loop
+ * index can be accessed as <b>var</b>_sl_idx and the length of the list can
+ * be accessed as <b>var</b>_sl_len.
+ *
+ * NOTE: Do not change the length of the list while the loop is in progress,
+ * unless you adjust the _sl_len variable correspondingly.  See second example
+ * below.
+ *
+ * Example use:
+ * <pre>
+ *   smartlist_t *list = smartlist_split("A:B:C", ":", 0, 0);
+ *   SMARTLIST_FOREACH_BEGIN(list, char *, cp) {
+ *     printf("%d: %s\n", cp_sl_idx, cp);
+ *     tor_free(cp);
+ *   } SMARTLIST_FOREACH_END(cp);
+ *   smartlist_free(list);
+ * </pre>
+ *
+ * Example use (advanced):
+ * <pre>
+ *   SMARTLIST_FOREACH_BEGIN(list, char *, cp) {
+ *     if (!strcmp(cp, "junk")) {
+ *       tor_free(cp);
+ *       SMARTLIST_DEL_CURRENT(list, cp);
+ *     }
+ *   } SMARTLIST_FOREACH_END(cp);
+ * </pre>
+ */
+/* Note: these macros use token pasting, and reach into smartlist internals.
+ * This can make them a little daunting. Here's the approximate unpacking of
+ * the above examples, for entertainment value:
+ *
+ * <pre>
+ * smartlist_t *list = smartlist_split("A:B:C", ":", 0, 0);
+ * {
+ *   int cp_sl_idx, cp_sl_len = smartlist_len(list);
+ *   char *cp;
+ *   for (cp_sl_idx = 0; cp_sl_idx < cp_sl_len; ++cp_sl_idx) {
+ *     cp = smartlist_get(list, cp_sl_idx);
+ *     printf("%d: %s\n", cp_sl_idx, cp);
+ *     tor_free(cp);
+ *   }
+ * }
+ * smartlist_free(list);
+ * </pre>
+ *
+ * <pre>
+ * {
+ *   int cp_sl_idx, cp_sl_len = smartlist_len(list);
+ *   char *cp;
+ *   for (cp_sl_idx = 0; cp_sl_idx < cp_sl_len; ++cp_sl_idx) {
+ *     cp = smartlist_get(list, cp_sl_idx);
+ *     if (!strcmp(cp, "junk")) {
+ *       tor_free(cp);
+ *       smartlist_del(list, cp_sl_idx);
+ *       --cp_sl_idx;
+ *       --cp_sl_len;
+ *     }
+ *   }
+ * }
+ * </pre>
+ */
+#define SMARTLIST_FOREACH_BEGIN(sl, type, var)  \
+  STMT_BEGIN                                                    \
+    int var ## _sl_idx, var ## _sl_len=(sl)->num_used;          \
+    type var;                                                   \
+    for (var ## _sl_idx = 0; var ## _sl_idx < var ## _sl_len;   \
+         ++var ## _sl_idx) {                                    \
+      var = (sl)->list[var ## _sl_idx];
+
+#define SMARTLIST_FOREACH_END(var)              \
+    var = NULL;                                 \
+    (void) var ## _sl_idx;                      \
+  } STMT_END
+
+/**
+ * An alias for SMARTLIST_FOREACH_BEGIN and SMARTLIST_FOREACH_END, using
+ * <b>cmd</b> as the loop body.  This wrapper is here for convenience with
+ * very short loops.
+ *
+ * By convention, we do not use this for loops which nest, or for loops over
+ * 10 lines or so.  Use SMARTLIST_FOREACH_{BEGIN,END} for those.
+ */
+#define SMARTLIST_FOREACH(sl, type, var, cmd)                   \
+  SMARTLIST_FOREACH_BEGIN(sl,type,var) {                        \
+    cmd;                                                        \
+  } SMARTLIST_FOREACH_END(var)
+
+/** Helper: While in a SMARTLIST_FOREACH loop over the list <b>sl</b> indexed
+ * with the variable <b>var</b>, remove the current element in a way that
+ * won't confuse the loop. */
+#define SMARTLIST_DEL_CURRENT(sl, var)          \
+  STMT_BEGIN                                    \
+    smartlist_del(sl, var ## _sl_idx);          \
+    --var ## _sl_idx;                           \
+    --var ## _sl_len;                           \
+  STMT_END
+
+/** Helper: While in a SMARTLIST_FOREACH loop over the list <b>sl</b> indexed
+ * with the variable <b>var</b>, remove the current element in a way that
+ * won't confuse the loop. */
+#define SMARTLIST_DEL_CURRENT_KEEPORDER(sl, var)          \
+  STMT_BEGIN                                              \
+     smartlist_del_keeporder(sl, var ## _sl_idx);         \
+     --var ## _sl_idx;                                    \
+     --var ## _sl_len;                                    \
+  STMT_END
+
+/** Helper: While in a SMARTLIST_FOREACH loop over the list <b>sl</b> indexed
+ * with the variable <b>var</b>, replace the current element with <b>val</b>.
+ * Does not deallocate the current value of <b>var</b>.
+ */
+#define SMARTLIST_REPLACE_CURRENT(sl, var, val) \
+  STMT_BEGIN                                    \
+    smartlist_set(sl, var ## _sl_idx, val);     \
+  STMT_END
+
+/* Helper: Given two lists of items, possibly of different types, such that
+ * both lists are sorted on some common field (as determined by a comparison
+ * expression <b>cmpexpr</b>), and such that one list (<b>sl1</b>) has no
+ * duplicates on the common field, loop through the lists in lockstep, and
+ * execute <b>unmatched_var2</b> on items in var2 that do not appear in
+ * var1.
+ *
+ * WARNING: It isn't safe to add remove elements from either list while the
+ * loop is in progress.
+ *
+ * Example use:
+ *  SMARTLIST_FOREACH_JOIN(routerstatus_list, routerstatus_t *, rs,
+ *                     routerinfo_list, routerinfo_t *, ri,
+ *                    tor_memcmp(rs->identity_digest, ri->identity_digest, 20),
+ *                     log_info(LD_GENERAL,"No match for %s", ri->nickname)) {
+ *    log_info(LD_GENERAL, "%s matches routerstatus %p", ri->nickname, rs);
+ * } SMARTLIST_FOREACH_JOIN_END(rs, ri);
+ **/
+/* The example above unpacks (approximately) to:
+ *  int rs_sl_idx = 0, rs_sl_len = smartlist_len(routerstatus_list);
+ *  int ri_sl_idx, ri_sl_len = smartlist_len(routerinfo_list);
+ *  int rs_ri_cmp;
+ *  routerstatus_t *rs;
+ *  routerinfo_t *ri;
+ *  for (; ri_sl_idx < ri_sl_len; ++ri_sl_idx) {
+ *    ri = smartlist_get(routerinfo_list, ri_sl_idx);
+ *    while (rs_sl_idx < rs_sl_len) {
+ *      rs = smartlist_get(routerstatus_list, rs_sl_idx);
+ *      rs_ri_cmp = tor_memcmp(rs->identity_digest, ri->identity_digest, 20);
+ *      if (rs_ri_cmp > 0) {
+ *        break;
+ *      } else if (rs_ri_cmp == 0) {
+ *        goto matched_ri;
+ *      } else {
+ *        ++rs_sl_idx;
+ *      }
+ *    }
+ *    log_info(LD_GENERAL,"No match for %s", ri->nickname);
+ *    continue;
+ *   matched_ri: {
+ *    log_info(LD_GENERAL,"%s matches with routerstatus %p",ri->nickname,rs);
+ *    }
+ *  }
+ */
+#define SMARTLIST_FOREACH_JOIN(sl1, type1, var1, sl2, type2, var2,      \
+                                cmpexpr, unmatched_var2)                \
+  STMT_BEGIN                                                            \
+  int var1 ## _sl_idx = 0, var1 ## _sl_len=(sl1)->num_used;             \
+  int var2 ## _sl_idx = 0, var2 ## _sl_len=(sl2)->num_used;             \
+  int var1 ## _ ## var2 ## _cmp;                                        \
+  type1 var1;                                                           \
+  type2 var2;                                                           \
+  for (; var2##_sl_idx < var2##_sl_len; ++var2##_sl_idx) {              \
+    var2 = (sl2)->list[var2##_sl_idx];                                  \
+    while (var1##_sl_idx < var1##_sl_len) {                             \
+      var1 = (sl1)->list[var1##_sl_idx];                                \
+      var1##_##var2##_cmp = (cmpexpr);                                  \
+      if (var1##_##var2##_cmp > 0) {                                    \
+        break;                                                          \
+      } else if (var1##_##var2##_cmp == 0) {                            \
+        goto matched_##var2;                                            \
+      } else {                                                          \
+        ++var1##_sl_idx;                                                \
+      }                                                                 \
+    }                                                                   \
+    /* Ran out of v1, or no match for var2. */                          \
+    unmatched_var2;                                                     \
+    continue;                                                           \
+    matched_##var2: ;                                                   \
+
+#define SMARTLIST_FOREACH_JOIN_END(var1, var2)  \
+  }                                             \
+  STMT_END
+
+#define DECLARE_MAP_FNS(maptype, keytype, prefix)                       \
+  typedef struct maptype maptype;                                       \
+  typedef struct prefix##entry_t *prefix##iter_t;                       \
+  MOCK_DECL(maptype*, prefix##new, (void));                             \
+  void* prefix##set(maptype *map, keytype key, void *val);              \
+  void* prefix##get(const maptype *map, keytype key);                   \
+  void* prefix##remove(maptype *map, keytype key);                      \
+  MOCK_DECL(void, prefix##free_, (maptype *map, void (*free_val)(void*))); \
+  int prefix##isempty(const maptype *map);                              \
+  int prefix##size(const maptype *map);                                 \
+  prefix##iter_t *prefix##iter_init(maptype *map);                      \
+  prefix##iter_t *prefix##iter_next(maptype *map, prefix##iter_t *iter); \
+  prefix##iter_t *prefix##iter_next_rmv(maptype *map, prefix##iter_t *iter); \
+  void prefix##iter_get(prefix##iter_t *iter, keytype *keyp, void **valp); \
+  int prefix##iter_done(prefix##iter_t *iter);                          \
+  void prefix##assert_ok(const maptype *map)
+
+/* Map from const char * to void *. Implemented with a hash table. */
+DECLARE_MAP_FNS(strmap_t, const char *, strmap_);
+/* Map from const char[DIGEST_LEN] to void *. Implemented with a hash table. */
+DECLARE_MAP_FNS(digestmap_t, const char *, digestmap_);
+/* Map from const uint8_t[DIGEST256_LEN] to void *. Implemented with a hash
+ * table. */
+DECLARE_MAP_FNS(digest256map_t, const uint8_t *, digest256map_);
+
+#define MAP_FREE_AND_NULL(maptype, map, fn)     \
+  do {                                          \
+    maptype ## _free_((map), (fn));             \
+    (map) = NULL;                               \
+  } while (0)
+
+#define strmap_free(map, fn) MAP_FREE_AND_NULL(strmap, (map), (fn))
+#define digestmap_free(map, fn) MAP_FREE_AND_NULL(digestmap, (map), (fn))
+#define digest256map_free(map, fn) MAP_FREE_AND_NULL(digest256map, (map), (fn))
+
+#undef DECLARE_MAP_FNS
+
+/** Iterates over the key-value pairs in a map <b>map</b> in order.
+ * <b>prefix</b> is as for DECLARE_MAP_FNS (i.e., strmap_ or digestmap_).
+ * The map's keys and values are of type keytype and valtype respectively;
+ * each iteration assigns them to keyvar and valvar.
+ *
+ * Example use:
+ *   MAP_FOREACH(digestmap_, m, const char *, k, routerinfo_t *, r) {
+ *     // use k and r
+ *   } MAP_FOREACH_END.
+ */
+/* Unpacks to, approximately:
+ * {
+ *   digestmap_iter_t *k_iter;
+ *   for (k_iter = digestmap_iter_init(m); !digestmap_iter_done(k_iter);
+ *        k_iter = digestmap_iter_next(m, k_iter)) {
+ *     const char *k;
+ *     void *r_voidp;
+ *     routerinfo_t *r;
+ *     digestmap_iter_get(k_iter, &k, &r_voidp);
+ *     r = r_voidp;
+ *     // use k and r
+ *   }
+ * }
+ */
+#define MAP_FOREACH(prefix, map, keytype, keyvar, valtype, valvar)      \
+  STMT_BEGIN                                                            \
+    prefix##iter_t *keyvar##_iter;                                      \
+    for (keyvar##_iter = prefix##iter_init(map);                        \
+         !prefix##iter_done(keyvar##_iter);                             \
+         keyvar##_iter = prefix##iter_next(map, keyvar##_iter)) {       \
+      keytype keyvar;                                                   \
+      void *valvar##_voidp;                                             \
+      valtype valvar;                                                   \
+      prefix##iter_get(keyvar##_iter, &keyvar, &valvar##_voidp);        \
+      valvar = valvar##_voidp;
+
+/** As MAP_FOREACH, except allows members to be removed from the map
+ * during the iteration via MAP_DEL_CURRENT.  Example use:
+ *
+ * Example use:
+ *   MAP_FOREACH(digestmap_, m, const char *, k, routerinfo_t *, r) {
+ *      if (is_very_old(r))
+ *       MAP_DEL_CURRENT(k);
+ *   } MAP_FOREACH_END.
+ **/
+/* Unpacks to, approximately:
+ * {
+ *   digestmap_iter_t *k_iter;
+ *   int k_del=0;
+ *   for (k_iter = digestmap_iter_init(m); !digestmap_iter_done(k_iter);
+ *        k_iter = k_del ? digestmap_iter_next(m, k_iter)
+ *                       : digestmap_iter_next_rmv(m, k_iter)) {
+ *     const char *k;
+ *     void *r_voidp;
+ *     routerinfo_t *r;
+ *     k_del=0;
+ *     digestmap_iter_get(k_iter, &k, &r_voidp);
+ *     r = r_voidp;
+ *     if (is_very_old(r)) {
+ *       k_del = 1;
+ *     }
+ *   }
+ * }
+ */
+#define MAP_FOREACH_MODIFY(prefix, map, keytype, keyvar, valtype, valvar) \
+  STMT_BEGIN                                                            \
+    prefix##iter_t *keyvar##_iter;                                      \
+    int keyvar##_del=0;                                                 \
+    for (keyvar##_iter = prefix##iter_init(map);                        \
+         !prefix##iter_done(keyvar##_iter);                             \
+         keyvar##_iter = keyvar##_del ?                                 \
+           prefix##iter_next_rmv(map, keyvar##_iter) :                  \
+           prefix##iter_next(map, keyvar##_iter)) {                     \
+      keytype keyvar;                                                   \
+      void *valvar##_voidp;                                             \
+      valtype valvar;                                                   \
+      keyvar##_del=0;                                                   \
+      prefix##iter_get(keyvar##_iter, &keyvar, &valvar##_voidp);        \
+      valvar = valvar##_voidp;
+
+/** Used with MAP_FOREACH_MODIFY to remove the currently-iterated-upon
+ * member of the map.  */
+#define MAP_DEL_CURRENT(keyvar)                   \
+  STMT_BEGIN                                      \
+    keyvar##_del = 1;                             \
+  STMT_END
+
+/** Used to end a MAP_FOREACH() block. */
+#define MAP_FOREACH_END } STMT_END ;
+
+/** As MAP_FOREACH, but does not require declaration of prefix or keytype.
+ * Example use:
+ *   DIGESTMAP_FOREACH(m, k, routerinfo_t *, r) {
+ *     // use k and r
+ *   } DIGESTMAP_FOREACH_END.
+ */
+#define DIGESTMAP_FOREACH(map, keyvar, valtype, valvar)                 \
+  MAP_FOREACH(digestmap_, map, const char *, keyvar, valtype, valvar)
+
+/** As MAP_FOREACH_MODIFY, but does not require declaration of prefix or
+ * keytype.
+ * Example use:
+ *   DIGESTMAP_FOREACH_MODIFY(m, k, routerinfo_t *, r) {
+ *      if (is_very_old(r))
+ *       MAP_DEL_CURRENT(k);
+ *   } DIGESTMAP_FOREACH_END.
+ */
+#define DIGESTMAP_FOREACH_MODIFY(map, keyvar, valtype, valvar)          \
+  MAP_FOREACH_MODIFY(digestmap_, map, const char *, keyvar, valtype, valvar)
+/** Used to end a DIGESTMAP_FOREACH() block. */
+#define DIGESTMAP_FOREACH_END MAP_FOREACH_END
+
+#define DIGEST256MAP_FOREACH(map, keyvar, valtype, valvar)               \
+  MAP_FOREACH(digest256map_, map, const uint8_t *, keyvar, valtype, valvar)
+#define DIGEST256MAP_FOREACH_MODIFY(map, keyvar, valtype, valvar)       \
+  MAP_FOREACH_MODIFY(digest256map_, map, const uint8_t *,               \
+                     keyvar, valtype, valvar)
+#define DIGEST256MAP_FOREACH_END MAP_FOREACH_END
+
+#define STRMAP_FOREACH(map, keyvar, valtype, valvar)                 \
+  MAP_FOREACH(strmap_, map, const char *, keyvar, valtype, valvar)
+#define STRMAP_FOREACH_MODIFY(map, keyvar, valtype, valvar)          \
+  MAP_FOREACH_MODIFY(strmap_, map, const char *, keyvar, valtype, valvar)
+#define STRMAP_FOREACH_END MAP_FOREACH_END
+
+void* strmap_set_lc(strmap_t *map, const char *key, void *val);
+void* strmap_get_lc(const strmap_t *map, const char *key);
+void* strmap_remove_lc(strmap_t *map, const char *key);
+
+#define DECLARE_TYPED_DIGESTMAP_FNS(prefix, maptype, valtype)           \
+  typedef struct maptype maptype;                                       \
+  typedef struct prefix##iter_t *prefix##iter_t;                        \
+  ATTR_UNUSED static inline maptype*                                    \
+  prefix##new(void)                                                     \
+  {                                                                     \
+    return (maptype*)digestmap_new();                                   \
+  }                                                                     \
+  ATTR_UNUSED static inline digestmap_t*                                \
+  prefix##to_digestmap(maptype *map)                                    \
+  {                                                                     \
+    return (digestmap_t*)map;                                           \
+  }                                                                     \
+  ATTR_UNUSED static inline valtype*                                    \
+  prefix##get(maptype *map, const char *key)     \
+  {                                                                     \
+    return (valtype*)digestmap_get((digestmap_t*)map, key);             \
+  }                                                                     \
+  ATTR_UNUSED static inline valtype*                                    \
+  prefix##set(maptype *map, const char *key, valtype *val)              \
+  {                                                                     \
+    return (valtype*)digestmap_set((digestmap_t*)map, key, val);        \
+  }                                                                     \
+  ATTR_UNUSED static inline valtype*                                    \
+  prefix##remove(maptype *map, const char *key)                         \
+  {                                                                     \
+    return (valtype*)digestmap_remove((digestmap_t*)map, key);          \
+  }                                                                     \
+  ATTR_UNUSED static inline void                                        \
+  prefix##f##ree_(maptype *map, void (*free_val)(void*))                \
+  {                                                                     \
+    digestmap_free_((digestmap_t*)map, free_val);                       \
+  }                                                                     \
+  ATTR_UNUSED static inline int                                         \
+  prefix##isempty(maptype *map)                                         \
+  {                                                                     \
+    return digestmap_isempty((digestmap_t*)map);                        \
+  }                                                                     \
+  ATTR_UNUSED static inline int                                         \
+  prefix##size(maptype *map)                                            \
+  {                                                                     \
+    return digestmap_size((digestmap_t*)map);                           \
+  }                                                                     \
+  ATTR_UNUSED static inline                                             \
+  prefix##iter_t *prefix##iter_init(maptype *map)                       \
+  {                                                                     \
+    return (prefix##iter_t*) digestmap_iter_init((digestmap_t*)map);    \
+  }                                                                     \
+  ATTR_UNUSED static inline                                             \
+  prefix##iter_t *prefix##iter_next(maptype *map, prefix##iter_t *iter) \
+  {                                                                     \
+    return (prefix##iter_t*) digestmap_iter_next(                       \
+                       (digestmap_t*)map, (digestmap_iter_t*)iter);     \
+  }                                                                     \
+  ATTR_UNUSED static inline prefix##iter_t*                             \
+  prefix##iter_next_rmv(maptype *map, prefix##iter_t *iter)             \
+  {                                                                     \
+    return (prefix##iter_t*) digestmap_iter_next_rmv(                   \
+                       (digestmap_t*)map, (digestmap_iter_t*)iter);     \
+  }                                                                     \
+  ATTR_UNUSED static inline void                                        \
+  prefix##iter_get(prefix##iter_t *iter,                                \
+                   const char **keyp,                                   \
+                   valtype **valp)                                      \
+  {                                                                     \
+    void *v;                                                            \
+    digestmap_iter_get((digestmap_iter_t*) iter, keyp, &v);             \
+    *valp = v;                                                          \
+  }                                                                     \
+  ATTR_UNUSED static inline int                                         \
+  prefix##iter_done(prefix##iter_t *iter)                               \
+  {                                                                     \
+    return digestmap_iter_done((digestmap_iter_t*)iter);                \
+  }
+
+#if SIZEOF_INT == 4
+#define BITARRAY_SHIFT 5
+#elif SIZEOF_INT == 8
+#define BITARRAY_SHIFT 6
+#else
+#error "int is neither 4 nor 8 bytes. I can't deal with that."
+#endif /* SIZEOF_INT == 4 || ... */
+#define BITARRAY_MASK ((1u<<BITARRAY_SHIFT)-1)
+
+/** A random-access array of one-bit-wide elements. */
+typedef unsigned int bitarray_t;
+/** Create a new bit array that can hold <b>n_bits</b> bits. */
+static inline bitarray_t *
+bitarray_init_zero(unsigned int n_bits)
+{
+  /* round up to the next int. */
+  size_t sz = (n_bits+BITARRAY_MASK) >> BITARRAY_SHIFT;
+  return tor_calloc(sz, sizeof(unsigned int));
+}
+/** Expand <b>ba</b> from holding <b>n_bits_old</b> to <b>n_bits_new</b>,
+ * clearing all new bits.  Returns a possibly changed pointer to the
+ * bitarray. */
+static inline bitarray_t *
+bitarray_expand(bitarray_t *ba,
+                unsigned int n_bits_old, unsigned int n_bits_new)
+{
+  size_t sz_old = (n_bits_old+BITARRAY_MASK) >> BITARRAY_SHIFT;
+  size_t sz_new = (n_bits_new+BITARRAY_MASK) >> BITARRAY_SHIFT;
+  char *ptr;
+  if (sz_new <= sz_old)
+    return ba;
+  ptr = tor_reallocarray(ba, sz_new, sizeof(unsigned int));
+  /* This memset does nothing to the older excess bytes.  But they were
+   * already set to 0 by bitarry_init_zero. */
+  memset(ptr+sz_old*sizeof(unsigned int), 0,
+         (sz_new-sz_old)*sizeof(unsigned int));
+  return (bitarray_t*) ptr;
+}
+/** Free the bit array <b>ba</b>. */
+static inline void
+bitarray_free_(bitarray_t *ba)
+{
+  tor_free(ba);
+}
+#define bitarray_free(ba) FREE_AND_NULL(bitarray_t, bitarray_free_, (ba))
+
+/** Set the <b>bit</b>th bit in <b>b</b> to 1. */
+static inline void
+bitarray_set(bitarray_t *b, int bit)
+{
+  b[bit >> BITARRAY_SHIFT] |= (1u << (bit & BITARRAY_MASK));
+}
+/** Set the <b>bit</b>th bit in <b>b</b> to 0. */
+static inline void
+bitarray_clear(bitarray_t *b, int bit)
+{
+  b[bit >> BITARRAY_SHIFT] &= ~ (1u << (bit & BITARRAY_MASK));
+}
+/** Return true iff <b>bit</b>th bit in <b>b</b> is nonzero.  NOTE: does
+ * not necessarily return 1 on true. */
+static inline unsigned int
+bitarray_is_set(bitarray_t *b, int bit)
+{
+  return b[bit >> BITARRAY_SHIFT] & (1u << (bit & BITARRAY_MASK));
+}
+
+/** A set of digests, implemented as a Bloom filter. */
+typedef struct {
+  int mask; /**< One less than the number of bits in <b>ba</b>; always one less
+             * than a power of two. */
+  bitarray_t *ba; /**< A bit array to implement the Bloom filter. */
+} digestset_t;
+
+#define BIT(n) ((n) & set->mask)
+/** Add the digest <b>digest</b> to <b>set</b>. */
+static inline void
+digestset_add(digestset_t *set, const char *digest)
+{
+  const uint64_t x = siphash24g(digest, 20);
+  const uint32_t d1 = (uint32_t) x;
+  const uint32_t d2 = (uint32_t)( (x>>16) + x);
+  const uint32_t d3 = (uint32_t)( (x>>32) + x);
+  const uint32_t d4 = (uint32_t)( (x>>48) + x);
+  bitarray_set(set->ba, BIT(d1));
+  bitarray_set(set->ba, BIT(d2));
+  bitarray_set(set->ba, BIT(d3));
+  bitarray_set(set->ba, BIT(d4));
+}
+
+/** If <b>digest</b> is in <b>set</b>, return nonzero.  Otherwise,
+ * <em>probably</em> return zero. */
+static inline int
+digestset_contains(const digestset_t *set, const char *digest)
+{
+  const uint64_t x = siphash24g(digest, 20);
+  const uint32_t d1 = (uint32_t) x;
+  const uint32_t d2 = (uint32_t)( (x>>16) + x);
+  const uint32_t d3 = (uint32_t)( (x>>32) + x);
+  const uint32_t d4 = (uint32_t)( (x>>48) + x);
+  return bitarray_is_set(set->ba, BIT(d1)) &&
+         bitarray_is_set(set->ba, BIT(d2)) &&
+         bitarray_is_set(set->ba, BIT(d3)) &&
+         bitarray_is_set(set->ba, BIT(d4));
+}
+#undef BIT
+
+digestset_t *digestset_new(int max_elements);
+void digestset_free_(digestset_t* set);
+#define digestset_free(set) FREE_AND_NULL(digestset_t, digestset_free_, (set))
+
+/* These functions, given an <b>array</b> of <b>n_elements</b>, return the
+ * <b>nth</b> lowest element. <b>nth</b>=0 gives the lowest element;
+ * <b>n_elements</b>-1 gives the highest; and (<b>n_elements</b>-1) / 2 gives
+ * the median.  As a side effect, the elements of <b>array</b> are sorted. */
+int find_nth_int(int *array, int n_elements, int nth);
+time_t find_nth_time(time_t *array, int n_elements, int nth);
+double find_nth_double(double *array, int n_elements, int nth);
+int32_t find_nth_int32(int32_t *array, int n_elements, int nth);
+uint32_t find_nth_uint32(uint32_t *array, int n_elements, int nth);
+long find_nth_long(long *array, int n_elements, int nth);
+static inline int
+median_int(int *array, int n_elements)
+{
+  return find_nth_int(array, n_elements, (n_elements-1)/2);
+}
+static inline time_t
+median_time(time_t *array, int n_elements)
+{
+  return find_nth_time(array, n_elements, (n_elements-1)/2);
+}
+static inline double
+median_double(double *array, int n_elements)
+{
+  return find_nth_double(array, n_elements, (n_elements-1)/2);
+}
+static inline uint32_t
+median_uint32(uint32_t *array, int n_elements)
+{
+  return find_nth_uint32(array, n_elements, (n_elements-1)/2);
+}
+static inline int32_t
+median_int32(int32_t *array, int n_elements)
+{
+  return find_nth_int32(array, n_elements, (n_elements-1)/2);
+}
+
+static inline uint32_t
+third_quartile_uint32(uint32_t *array, int n_elements)
+{
+  return find_nth_uint32(array, n_elements, (n_elements*3)/4);
+}
+
+#endif /* !defined(TOR_CONTAINER_H) */