Implement proposal 227-vote-on-package-fingerprints.txt

This implementation includes tests and a little documentation.

2 files changed, 24 insertions, 6 deletions

diff --git a/src/common/container.c b/src/common/container.c
index 37e28004ae..68e3711c90 100644
--- a/src/common/container.c
+++ b/src/common/container.c
@@ -518,11 +518,13 @@ smartlist_sort(smartlist_t *sl, int (*compare)(const void **a, const void **b))
 
 /** Given a smartlist <b>sl</b> sorted with the function <b>compare</b>,
  * return the most frequent member in the list.  Break ties in favor of
- * later elements.  If the list is empty, return NULL.
+ * later elements.  If the list is empty, return NULL.  If count_out is
+ * non-null, set it to the most frequent member.
  */
 void *
-smartlist_get_most_frequent(const smartlist_t *sl,
-                            int (*compare)(const void **a, const void **b))
+smartlist_get_most_frequent_(const smartlist_t *sl,
+                             int (*compare)(const void **a, const void **b),
+                             int *count_out)
 {
   const void *most_frequent = NULL;
   int most_frequent_count = 0;
@@ -530,8 +532,11 @@ smartlist_get_most_frequent(const smartlist_t *sl,
   const void *cur = NULL;
   int i, count=0;
 
-  if (!sl->num_used)
+  if (!sl->num_used) {
+    if (count_out)
+      *count_out = 0;
     return NULL;
+  }
   for (i = 0; i < sl->num_used; ++i) {
     const void *item = sl->list[i];
     if (cur && 0 == compare(&cur, &item)) {
@@ -549,6 +554,8 @@ smartlist_get_most_frequent(const smartlist_t *sl,
     most_frequent = cur;
     most_frequent_count = count;
   }
+  if (count_out)
+    *count_out = most_frequent_count;
   return (void*)most_frequent;
 }
 
@@ -728,6 +735,13 @@ smartlist_get_most_frequent_string(smartlist_t *sl)
   return smartlist_get_most_frequent(sl, compare_string_ptrs_);
 }
 
+/** Return the most frequent string in the sorted list <b>sl</b> */
+char *
+smartlist_get_most_frequent_string_(smartlist_t *sl, int *count_out)
+{
+  return smartlist_get_most_frequent_(sl, compare_string_ptrs_, count_out);
+}
+
 /** Remove duplicate strings from a sorted list, and free them with tor_free().
  */
 void
diff --git a/src/common/container.h b/src/common/container.h
index 377cdf5dba..6edc80f75b 100644
--- a/src/common/container.h
+++ b/src/common/container.h
@@ -94,8 +94,11 @@ 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));
+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));
@@ -106,6 +109,7 @@ void smartlist_sort_digests256(smartlist_t *sl);
 void smartlist_sort_pointers(smartlist_t *sl);
 
 char *smartlist_get_most_frequent_string(smartlist_t *sl);
+char *smartlist_get_most_frequent_string_(smartlist_t *sl, int *count_out);
 char *smartlist_get_most_frequent_digest256(smartlist_t *sl);
 
 void smartlist_uniq_strings(smartlist_t *sl);