+#define util_as_integral(elem) ((intptr_t)((elem)->util))
+
+static void record_person(int which, struct string_list *people,
+ struct commit *commit)
+{
+ char name_buf[MAX_GITNAME], *name, *name_end;
+ struct string_list_item *elem;
+ const char *field = (which == 'a') ? "\nauthor " : "\ncommitter ";
+
+ name = strstr(commit->buffer, field);
+ if (!name)
+ return;
+ name += strlen(field);
+ name_end = strchrnul(name, '<');
+ if (*name_end)
+ name_end--;
+ while (isspace(*name_end) && name <= name_end)
+ name_end--;
+ if (name_end < name || name + MAX_GITNAME <= name_end)
+ return;
+ memcpy(name_buf, name, name_end - name + 1);
+ name_buf[name_end - name + 1] = '\0';
+
+ elem = string_list_lookup(people, name_buf);
+ if (!elem) {
+ elem = string_list_insert(people, name_buf);
+ elem->util = (void *)0;
+ }
+ elem->util = (void*)(util_as_integral(elem) + 1);
+}
+
+static int cmp_string_list_util_as_integral(const void *a_, const void *b_)
+{
+ const struct string_list_item *a = a_, *b = b_;
+ return util_as_integral(b) - util_as_integral(a);
+}
+
+static void add_people_count(struct strbuf *out, struct string_list *people)
+{
+ if (people->nr == 1)
+ strbuf_addf(out, "%s", people->items[0].string);
+ else if (people->nr == 2)
+ strbuf_addf(out, "%s (%d) and %s (%d)",
+ people->items[0].string,
+ (int)util_as_integral(&people->items[0]),
+ people->items[1].string,
+ (int)util_as_integral(&people->items[1]));
+ else if (people->nr)
+ strbuf_addf(out, "%s (%d) and others",
+ people->items[0].string,
+ (int)util_as_integral(&people->items[0]));
+}
+
+static void credit_people(struct strbuf *out,
+ struct string_list *them,
+ int kind)
+{
+ const char *label;
+ const char *me;
+
+ if (kind == 'a') {
+ label = "\nBy ";
+ me = git_author_info(IDENT_NO_DATE);
+ } else {
+ label = "\nvia ";
+ me = git_committer_info(IDENT_NO_DATE);
+ }
+
+ if (!them->nr ||
+ (them->nr == 1 &&
+ me &&
+ (me = skip_prefix(me, them->items->string)) != NULL &&
+ skip_prefix(me, " <")))
+ return;
+ strbuf_addstr(out, label);
+ add_people_count(out, them);
+}
+
+static void add_people_info(struct strbuf *out,
+ struct string_list *authors,
+ struct string_list *committers)
+{
+ if (authors->nr)
+ qsort(authors->items,
+ authors->nr, sizeof(authors->items[0]),
+ cmp_string_list_util_as_integral);
+ if (committers->nr)
+ qsort(committers->items,
+ committers->nr, sizeof(committers->items[0]),
+ cmp_string_list_util_as_integral);
+
+ credit_people(out, authors, 'a');
+ credit_people(out, committers, 'c');
+}
+