From a2ce2e9cfba9e4050d5de6b741899cbf9b05ad57 Mon Sep 17 00:00:00 2001
From: Koen Zandberg <koen@bergzand.net>
Date: Fri, 15 Jan 2021 11:25:03 +0100
Subject: [PATCH] memarray: Add memarray_available function

---
 sys/include/memarray.h  | 11 ++++++++++-
 sys/memarray/memarray.c | 11 +++++++++++
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/sys/include/memarray.h b/sys/include/memarray.h
index 68598c80ac..4d75b96c04 100644
--- a/sys/include/memarray.h
+++ b/sys/include/memarray.h
@@ -20,7 +20,7 @@
 
 #include <assert.h>
 #include <stdint.h>
-#include <stdlib.h>
+#include <stddef.h>
 #include <string.h>
 
 #ifdef __cplusplus
@@ -110,6 +110,15 @@ static inline void memarray_free(memarray_t *mem, void *ptr)
     mem->free_data = ptr;
 }
 
+/**
+ * @brief Returns the number of blocks available
+ *
+ * @param[in]   mem     memarray pool
+ *
+ * @returns             Number of elements available in the memarray pool
+ */
+size_t memarray_available(memarray_t *mem);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/sys/memarray/memarray.c b/sys/memarray/memarray.c
index f9f2a24efb..e618951c77 100644
--- a/sys/memarray/memarray.c
+++ b/sys/memarray/memarray.c
@@ -31,3 +31,14 @@ void memarray_init(memarray_t *mem, void *data, size_t size, size_t num)
         memarray_free(mem, element);
     }
 }
+
+size_t memarray_available(memarray_t *mem)
+{
+    size_t num = 0;
+    void **element = &mem->free_data;
+    while (*element) {
+        element = (void**)*element;
+        num++;
+    }
+    return num;
+}