Add some common macros

Add ARRAY_SIZE() and container_of() macros to this project.

Change-Id: Ic1bad59c01f97c4b1a56bbf41d2df61ed3d9e506
Signed-off-by: Krzysztof Opasiak <k.opasiak@samsung.com>

diff --git a/include/common.h b/include/common.h
new file mode 100644 (file)
index 0000000..2475f23
--- /dev/null
+++ b/include/common.h
@@ -0,0 +1,38 @@
+/*
+ * common.h
+ * Copyright (c) 2015 Samsung Electronics Co., Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef LIBHUSB_COMMON_H
+#define LIBHUSB_COMMON_H
+
+#include <stddef.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define container_of(ptr, type, field) ({                              \
+                       const typeof(((type *)0)->field) *member = (ptr); \
+                       (type *)( (char *)member - offsetof(type, field) ); \
+                })
+
+#define ARRAY_SIZE(a) (sizeof(a)/sizeof(*a))
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* LIBHUSB_COMMON_H */