idxset: Add set comparison operations

Add isdisjoint(), issubset(), issuperset() and equals() functions that
element-wise compare two idxsets.

Signed-off-by: Alper Nebi Yasak <alpernebiyasak@gmail.com>
Part-of: <https://gitlab.freedesktop.org/pulseaudio/pulseaudio/-/merge_requests/596>

2 files changed, 46 insertions, 0 deletions

diff --git a/src/pulsecore/idxset.c b/src/pulsecore/idxset.c
index 91ac6a015..b5dd9b3e1 100644
--- a/src/pulsecore/idxset.c
+++ b/src/pulsecore/idxset.c
@@ -470,6 +470,40 @@ bool pa_idxset_isempty(pa_idxset *s) {
     return s->n_entries == 0;
 }
 
+bool pa_idxset_isdisjoint(pa_idxset *s, pa_idxset *t) {
+    struct idxset_entry *i;
+
+    pa_assert(s);
+    pa_assert(t);
+
+    for (i = s->iterate_list_head; i; i = i->iterate_next)
+        if (pa_idxset_contains(t, i->data))
+            return false;
+
+    return true;
+}
+
+bool pa_idxset_issubset(pa_idxset *s, pa_idxset *t) {
+    struct idxset_entry *i;
+
+    pa_assert(s);
+    pa_assert(t);
+
+    for (i = s->iterate_list_head; i; i = i->iterate_next)
+        if (!pa_idxset_contains(t, i->data))
+            return false;
+
+    return true;
+}
+
+bool pa_idxset_issuperset(pa_idxset *s, pa_idxset *t) {
+    return pa_idxset_issubset(t, s);
+}
+
+bool pa_idxset_equals(pa_idxset *s, pa_idxset *t) {
+    return pa_idxset_issubset(s, t) && pa_idxset_issuperset(s, t);
+}
+
 pa_idxset *pa_idxset_copy(pa_idxset *s, pa_copy_func_t copy_func) {
     pa_idxset *copy;
     struct idxset_entry *i;
diff --git a/src/pulsecore/idxset.h b/src/pulsecore/idxset.h
index 6797852b7..ee530bf2b 100644
--- a/src/pulsecore/idxset.h
+++ b/src/pulsecore/idxset.h
@@ -107,6 +107,18 @@ unsigned pa_idxset_size(pa_idxset*s);
 /* Return true of the idxset is empty */
 bool pa_idxset_isempty(pa_idxset *s);
 
+/* Return true if s and t have no entries in common */
+bool pa_idxset_isdisjoint(pa_idxset *s, pa_idxset *t);
+
+/* Return true if all entries in s are also in t */
+bool pa_idxset_issubset(pa_idxset *s, pa_idxset *t);
+
+/* Return true if all entries in t are also in s */
+bool pa_idxset_issuperset(pa_idxset *s, pa_idxset *t);
+
+/* Return true if s and t have all entries in common */
+bool pa_idxset_equals(pa_idxset *s, pa_idxset *t);
+
 /* Duplicate the idxset. This will not copy the actual indexes. If copy_func is
  * set, each entry is copied using the provided function, otherwise a shallow
  * copy will be made. */