/*
- * Copyright (c) 2008, 2009, 2010 Nicira Networks.
+ * Copyright (c) 2008, 2009, 2010, 2011 Nicira, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
memset(set, 0, sizeof *set);
}
+static bool
+tag_is_worth_adding(const struct tag_set *set, tag_type tag)
+{
+ if (!tag) {
+ /* Nothing to add. */
+ return false;
+ } else if ((set->total & tag) != tag) {
+ /* 'set' doesn't have all the bits in 'tag', so we need to add it. */
+ return true;
+ } else {
+ /* We can drop it if some member of 'set' already includes all of the
+ * 1-bits in 'tag'. (tag_set_intersects() does a different test:
+ * whether some member of 'set' has at least two 1-bit in common with
+ * 'tag'.) */
+ int i;
+
+ for (i = 0; i < TAG_SET_SIZE; i++) {
+ if ((set->tags[i] & tag) == tag) {
+ return false;
+ }
+ }
+ return true;
+ }
+}
+
/* Adds 'tag' to 'set'. */
void
tag_set_add(struct tag_set *set, tag_type tag)
{
- if (tag && (!tag_is_valid(tag) || !tag_set_intersects(set, tag))) {
+ if (tag_is_worth_adding(set, tag)) {
/* XXX We could do better by finding the set member to which we would
* add the fewest number of 1-bits. This would reduce the amount of
* ambiguity, since e.g. three 1-bits match 3 * 2 / 2 = 3 unique tags
}
}
+/* Adds all the tags in 'other' to 'set'. */
+void
+tag_set_union(struct tag_set *set, const struct tag_set *other)
+{
+ size_t i;
+
+ for (i = 0; i < TAG_SET_SIZE; i++) {
+ tag_set_add(set, other->tags[i]);
+ }
+}