From fb0807d7696142d403bb6b18e14acabbdf2b9308 Mon Sep 17 00:00:00 2001
From: Daniel <daniel@tohka.us>
Date: Tue, 12 Mar 2019 01:08:27 +0200
Subject: [PATCH] putil: add is_allocated convenience method to
 UniqueIdAllocator

Closes #580
---
 panda/src/putil/uniqueIdAllocator.cxx | 14 ++++++++++++++
 panda/src/putil/uniqueIdAllocator.h   |  2 ++
 2 files changed, 16 insertions(+)

diff --git a/panda/src/putil/uniqueIdAllocator.cxx b/panda/src/putil/uniqueIdAllocator.cxx
index 6c4edd9795..19e3a8ee5a 100644
--- a/panda/src/putil/uniqueIdAllocator.cxx
+++ b/panda/src/putil/uniqueIdAllocator.cxx
@@ -173,6 +173,20 @@ initial_reserve_id(uint32_t id) {
   --_free;
 }
 
+/**
+ * Checks the allocated state of an index. Returns true for
+ * indices that are currently allocated and in use.
+ */
+bool UniqueIdAllocator::
+is_allocated(uint32_t id) {
+  if (id < _min || id > _max) {
+    // This id is out of range, not allocated.
+    return false;
+  }
+
+  uint32_t index = id - _min; // Convert to _table index.
+  return _table[index] == IndexAllocated;
+}
 
 /**
  * Free an allocated index (index must be between _min and _max that were
diff --git a/panda/src/putil/uniqueIdAllocator.h b/panda/src/putil/uniqueIdAllocator.h
index 50db80b0b0..2f3e3b9e8f 100644
--- a/panda/src/putil/uniqueIdAllocator.h
+++ b/panda/src/putil/uniqueIdAllocator.h
@@ -43,6 +43,8 @@ PUBLISHED:
   uint32_t allocate();
   void initial_reserve_id(uint32_t id);
 
+  bool is_allocated(uint32_t index);
+
   void free(uint32_t index);
   PN_stdfloat fraction_used() const;