first

rt-thread/components/utilities/libadt/ref/SConscript

@@ -0,0 +1,9 @@
+from building import *
+
+cwd     = GetCurrentDir()
+src     = list()
+CPPPATH = [cwd]
+group   = []
+
+group = DefineGroup('LIBADT', src, depend = ['RT_USING_ADT_REF'], CPPPATH = CPPPATH)
+Return('group')

rt-thread/components/utilities/libadt/ref/ref.h

@@ -0,0 +1,75 @@
+/*
+ * Copyright (c) 2006-2023, RT-Thread Development Team
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Change Logs:
+ * Date           Author       Notes
+ * 2022-3-1       zhouxiaohu   first version
+ * 2023-5-18      GuEe-GUI     implemented by rtatomic
+ */
+
+#ifndef __UTIL_REF_H__
+#define __UTIL_REF_H__
+
+#include <rtatomic.h>
+
+/**
+ * struct ref must be embedded in an object.
+ * it acts as a reference counter for the object.
+ */
+struct rt_ref
+{
+    rt_atomic_t refcount;
+};
+
+#define RT_REF_INIT(n)  { .refcount = n, }
+
+rt_inline void rt_ref_init(struct rt_ref *r)
+{
+    rt_atomic_store(&r->refcount, 1);
+}
+
+rt_inline unsigned int rt_ref_read(struct rt_ref *r)
+{
+    return rt_atomic_load(&r->refcount);
+}
+
+/**
+ * ref_get
+ * increment reference counter for object.
+ */
+rt_inline void rt_ref_get(struct rt_ref *r)
+{
+    rt_atomic_add(&r->refcount, 1);
+}
+
+/**
+ * ref_put
+ * decrement reference counter for object.
+ * If the reference counter is zero, call release().
+ *
+ * Return 1 means the object's reference counter is zero and release() is called.
+ */
+rt_inline int rt_ref_put(struct rt_ref *r, void (*release)(struct rt_ref *r))
+{
+    if (rt_atomic_dec_and_test(&r->refcount))
+    {
+        release(r);
+
+        return 1;
+    }
+
+    return 0;
+}
+
+/**
+ * ref_get_unless_zero - Increment refcount for object unless it is zero.
+ * Return non-zero if the increment succeeded. Otherwise return 0.
+ */
+rt_inline int rt_ref_get_unless_zero(struct rt_ref *r)
+{
+    return (int)rt_atomic_inc_not_zero(&r->refcount);
+}
+
+#endif /* __UTIL_REF_H__ */