From 236b7ee0e265b32d3d7ba163ea81a0792db1ca7d Mon Sep 17 00:00:00 2001
From: Wim Taymans <wtaymans@redhat.com>
Date: Mon, 27 Nov 2023 22:54:43 +0300
Subject: [PATCH] acp: Add idxset comparison and reverse search operations

Add contains() function that checks if an item is in an idxset. Add
isdisjoint(), issubset(), issuperset() and equals() functions that
element-wise compare two idxsets.

Add complementary functions to the existing idxset search(), first(),
next() functions that work in the reverse direction: reverse_search(),
last() and previous().

Add steal_last() to remove and return the last item in the idxset.

[Alper: original patches for PulseAudio, split from other commit]
Co-developed-by: Alper Nebi Yasak <alpernebiyasak@gmail.com>
Link: https://gitlab.freedesktop.org/pulseaudio/pulseaudio/-/commit/fb63e589310fab20e60c46bb40c7b7acab5eeac9
Link: https://gitlab.freedesktop.org/pulseaudio/pulseaudio/-/commit/ec668ac44bc6e666123f22f2696745dcdce98fed
Link: https://gitlab.freedesktop.org/pulseaudio/pulseaudio/-/commit/97d9c28579c7c7400969fd93f911e7745fb483ef
---
 spa/plugins/alsa/acp/idxset.h | 86 +++++++++++++++++++++++++++++++++--
 1 file changed, 81 insertions(+), 5 deletions(-)

diff --git a/spa/plugins/alsa/acp/idxset.h b/spa/plugins/alsa/acp/idxset.h
index 4a23eee35..2638133da 100644
--- a/spa/plugins/alsa/acp/idxset.h
+++ b/spa/plugins/alsa/acp/idxset.h
@@ -130,13 +130,25 @@ static inline unsigned pa_idxset_size(pa_idxset*s)
 	return count;
 }
 
-static inline void *pa_idxset_search(pa_idxset *s, uint32_t *idx)
+static inline pa_idxset_item *pa_idxset_search(pa_idxset *s, uint32_t *idx)
 {
         pa_idxset_item *item;
 	for (item = pa_array_get_unchecked(&s->array, *idx, pa_idxset_item);
 	     pa_array_check(&s->array, item); item++, (*idx)++) {
 		if (item->ptr != NULL)
-			return item->ptr;
+			return item;
+	}
+	*idx = PA_IDXSET_INVALID;
+	return NULL;
+}
+
+static inline pa_idxset_item *pa_idxset_reverse_search(pa_idxset *s, uint32_t *idx)
+{
+        pa_idxset_item *item;
+	for (item = pa_array_get_unchecked(&s->array, *idx, pa_idxset_item);
+	     pa_array_check(&s->array, item); item--, (*idx)--) {
+		if (item->ptr != NULL)
+			return item;
 	}
 	*idx = PA_IDXSET_INVALID;
 	return NULL;
@@ -144,29 +156,93 @@ static inline void *pa_idxset_search(pa_idxset *s, uint32_t *idx)
 
 static inline void *pa_idxset_next(pa_idxset *s, uint32_t *idx)
 {
+	pa_idxset_item *item;
 	(*idx)++;;
-	return pa_idxset_search(s, idx);
+	item = pa_idxset_search(s, idx);
+	return item ? item->ptr : NULL;
 }
 
 static inline void* pa_idxset_first(pa_idxset *s, uint32_t *idx)
 {
 	uint32_t i = 0;
-	void *ptr = pa_idxset_search(s, &i);
+	pa_idxset_item *item = pa_idxset_search(s, &i);
 	if (idx)
 		*idx = i;
+	return item ? item->ptr : NULL;
+}
+
+static inline void* pa_idxset_last(pa_idxset *s, uint32_t *idx)
+{
+	uint32_t i = pa_array_get_len(&s->array, pa_idxset_item) - 1;
+	pa_idxset_item *item = pa_idxset_reverse_search(s, &i);
+	if (idx)
+		*idx = i;
+	return item ? item->ptr : NULL;
+}
+
+static inline void* pa_idxset_steal_last(pa_idxset *s, uint32_t *idx)
+{
+	uint32_t i = pa_array_get_len(&s->array, pa_idxset_item) - 1;
+	void *ptr = NULL;
+	pa_idxset_item *item = pa_idxset_reverse_search(s, &i);
+	if (idx)
+		*idx = i;
+	if (item) {
+		ptr = item->ptr;
+		item->ptr = NULL;
+		pa_array_remove(&s->array, item);
+	}
 	return ptr;
 }
 
 static inline void* pa_idxset_get_by_data(pa_idxset*s, const void *p, uint32_t *idx)
 {
 	pa_idxset_item *item = pa_idxset_find(s, p);
-	if (item == NULL)
+	if (item == NULL) {
+		if (idx)
+			*idx = PA_IDXSET_INVALID;
 		return NULL;
+	}
 	if (idx)
 		*idx = item - (pa_idxset_item*)s->array.data;
 	return item->ptr;
 }
 
+static inline bool pa_idxset_contains(pa_idxset *s, const void *p)
+{
+	return pa_idxset_get_by_data(s, p, NULL) == p;
+}
+
+static inline bool pa_idxset_isdisjoint(pa_idxset *s, pa_idxset *t)
+{
+	pa_idxset_item *item;
+	pa_array_for_each(item, &s->array) {
+		if (item->ptr && pa_idxset_contains(t, item->ptr))
+			return false;
+	}
+	return true;
+}
+
+static inline bool pa_idxset_issubset(pa_idxset *s, pa_idxset *t)
+{
+	pa_idxset_item *item;
+	pa_array_for_each(item, &s->array) {
+		if (item->ptr && !pa_idxset_contains(t, item->ptr))
+			return false;
+	}
+	return true;
+}
+
+static inline bool pa_idxset_issuperset(pa_idxset *s, pa_idxset *t)
+{
+    return pa_idxset_issubset(t, s);
+}
+
+static inline bool pa_idxset_equals(pa_idxset *s, pa_idxset *t)
+{
+    return pa_idxset_issubset(s, t) && pa_idxset_issuperset(s, t);
+}
+
 static inline void* pa_idxset_get_by_index(pa_idxset*s, uint32_t idx)
 {
         pa_idxset_item *item;