nuttx/err.h add ERR_PTR IS_ERR IS_ERR_OR_NULL ERR_CAST PTR_ERR_OR_ZER…

include/nuttx/err.h

@@ -0,0 +1,100 @@
+/****************************************************************************
+ * include/nuttx/err.h
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you 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 __INCLUDE_NUTTX_ERR_H
+#define __INCLUDE_NUTTX_ERR_H
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+#include <nuttx/compiler.h>
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Kernel pointers have redundant information, so we can use a
+ * scheme where we can return either an error code or a normal
+ * pointer with the same return value.
+ *
+ * This should be a per-architecture thing, to allow different
+ * error and pointer decisions.
+ ****************************************************************************/
+
+#define MAX_ERRNO 4095
+
+#define IS_ERR_VALUE(x) predict_false((unsigned long)(FAR void *)(x) >= \
+                                      (unsigned long) - MAX_ERRNO)
+
+/****************************************************************************
+ * Inline Functions
+ ****************************************************************************/
+
+static inline FAR void *ERR_PTR(long error)
+{
+  return (FAR void *)error;
+}
+
+static inline long PTR_ERR(FAR const void *ptr)
+{
+  return (long)ptr;
+}
+
+static inline bool IS_ERR(FAR const void *ptr)
+{
+  return IS_ERR_VALUE((unsigned long)ptr);
+}
+
+static inline bool IS_ERR_OR_NULL(FAR const void *ptr)
+{
+  return predict_false(!ptr) || IS_ERR_VALUE((unsigned long)ptr);
+}
+
+/****************************************************************************
+ * Name: ERR_CAST
+ *
+ * Description:
+ * ERR_CAST - Explicitly cast an error-valued pointer to another pointer type
+ *
+ * ptr: The pointer to cast.
+ *
+ * Explicitly cast an error-valued pointer to another pointer type in such a
+ * way as to make it clear that's what's going on.
+ ****************************************************************************/
+
+static inline FAR void *ERR_CAST(FAR const void *ptr)
+{
+  /* cast away the const */
+
+  return (FAR void *)ptr;
+}
+
+static inline int PTR_ERR_OR_ZERO(FAR const void *ptr)
+{
+  if (IS_ERR(ptr))
+    return PTR_ERR(ptr);
+  else
+    return 0;
+}
+
+#endif /* __INCLUDE_NUTTX_ERR_H */