+/*
+ * Returns:
+ * 0 if we are under the limit;
+ * 1 if we need to disable inexact rename detection;
+ * 2 if we would be under the limit if we were given -C instead of -C -C.
+ */
+static int too_many_rename_candidates(int num_create,
+ struct diff_options *options)
+{
+ int rename_limit = options->rename_limit;
+ int num_src = rename_src_nr;
+ int i;
+
+ options->needed_rename_limit = 0;
+
+ /*
+ * This basically does a test for the rename matrix not
+ * growing larger than a "rename_limit" square matrix, ie:
+ *
+ * num_create * num_src > rename_limit * rename_limit
+ *
+ * but handles the potential overflow case specially (and we
+ * assume at least 32-bit integers)
+ */
+ if (rename_limit <= 0 || rename_limit > 32767)
+ rename_limit = 32767;
+ if ((num_create <= rename_limit || num_src <= rename_limit) &&
+ (num_create * num_src <= rename_limit * rename_limit))
+ return 0;
+
+ options->needed_rename_limit =
+ num_src > num_create ? num_src : num_create;
+
+ /* Are we running under -C -C? */
+ if (!DIFF_OPT_TST(options, FIND_COPIES_HARDER))
+ return 1;
+
+ /* Would we bust the limit if we were running under -C? */
+ for (num_src = i = 0; i < rename_src_nr; i++) {
+ if (diff_unmodified_pair(rename_src[i].p))
+ continue;
+ num_src++;
+ }
+ if ((num_create <= rename_limit || num_src <= rename_limit) &&
+ (num_create * num_src <= rename_limit * rename_limit))
+ return 2;
+ return 1;
+}
+