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authorJari Vetoniemi <jari.vetoniemi@indooratlas.com>2020-03-16 18:49:26 +0900
committerJari Vetoniemi <jari.vetoniemi@indooratlas.com>2020-03-30 00:39:06 +0900
commitfcbf63e62c627deae76c1b8cb8c0876c536ed811 (patch)
tree64cb17de3f41a2b6fef2368028fbd00349946994 /jni/ruby/ccan/container_of
Fresh start
Diffstat (limited to 'jni/ruby/ccan/container_of')
-rw-r--r--jni/ruby/ccan/container_of/container_of.h142
1 files changed, 142 insertions, 0 deletions
diff --git a/jni/ruby/ccan/container_of/container_of.h b/jni/ruby/ccan/container_of/container_of.h
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+++ b/jni/ruby/ccan/container_of/container_of.h
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+/* CC0 (Public domain) - see ccan/licenses/CC0 file for details */
+#ifndef CCAN_CONTAINER_OF_H
+#define CCAN_CONTAINER_OF_H
+#include "ccan/check_type/check_type.h"
+
+/**
+ * container_of - get pointer to enclosing structure
+ * @member_ptr: pointer to the structure member
+ * @containing_type: the type this member is within
+ * @member: the name of this member within the structure.
+ *
+ * Given a pointer to a member of a structure, this macro does pointer
+ * subtraction to return the pointer to the enclosing type.
+ *
+ * Example:
+ * struct foo {
+ * int fielda, fieldb;
+ * // ...
+ * };
+ * struct info {
+ * int some_other_field;
+ * struct foo my_foo;
+ * };
+ *
+ * static struct info *foo_to_info(struct foo *foo)
+ * {
+ * return container_of(foo, struct info, my_foo);
+ * }
+ */
+#define container_of(member_ptr, containing_type, member) \
+ ((containing_type *) \
+ ((char *)(member_ptr) \
+ - container_off(containing_type, member)) \
+ + check_types_match(*(member_ptr), ((containing_type *)0)->member))
+
+
+/**
+ * container_of_or_null - get pointer to enclosing structure, or NULL
+ * @member_ptr: pointer to the structure member
+ * @containing_type: the type this member is within
+ * @member: the name of this member within the structure.
+ *
+ * Given a pointer to a member of a structure, this macro does pointer
+ * subtraction to return the pointer to the enclosing type, unless it
+ * is given NULL, in which case it also returns NULL.
+ *
+ * Example:
+ * struct foo {
+ * int fielda, fieldb;
+ * // ...
+ * };
+ * struct info {
+ * int some_other_field;
+ * struct foo my_foo;
+ * };
+ *
+ * static struct info *foo_to_info_allowing_null(struct foo *foo)
+ * {
+ * return container_of_or_null(foo, struct info, my_foo);
+ * }
+ */
+static inline char *container_of_or_null_(void *member_ptr, size_t offset)
+{
+ return member_ptr ? (char *)member_ptr - offset : NULL;
+}
+#define container_of_or_null(member_ptr, containing_type, member) \
+ ((containing_type *) \
+ container_of_or_null_(member_ptr, \
+ container_off(containing_type, member)) \
+ + check_types_match(*(member_ptr), ((containing_type *)0)->member))
+
+/**
+ * container_off - get offset to enclosing structure
+ * @containing_type: the type this member is within
+ * @member: the name of this member within the structure.
+ *
+ * Given a pointer to a member of a structure, this macro does
+ * typechecking and figures out the offset to the enclosing type.
+ *
+ * Example:
+ * struct foo {
+ * int fielda, fieldb;
+ * // ...
+ * };
+ * struct info {
+ * int some_other_field;
+ * struct foo my_foo;
+ * };
+ *
+ * static struct info *foo_to_info(struct foo *foo)
+ * {
+ * size_t off = container_off(struct info, my_foo);
+ * return (void *)((char *)foo - off);
+ * }
+ */
+#define container_off(containing_type, member) \
+ offsetof(containing_type, member)
+
+/**
+ * container_of_var - get pointer to enclosing structure using a variable
+ * @member_ptr: pointer to the structure member
+ * @container_var: a pointer of same type as this member's container
+ * @member: the name of this member within the structure.
+ *
+ * Given a pointer to a member of a structure, this macro does pointer
+ * subtraction to return the pointer to the enclosing type.
+ *
+ * Example:
+ * static struct info *foo_to_i(struct foo *foo)
+ * {
+ * struct info *i = container_of_var(foo, i, my_foo);
+ * return i;
+ * }
+ */
+#if HAVE_TYPEOF
+#define container_of_var(member_ptr, container_var, member) \
+ container_of(member_ptr, typeof(*container_var), member)
+#else
+#define container_of_var(member_ptr, container_var, member) \
+ ((void *)((char *)(member_ptr) - \
+ container_off_var(container_var, member)))
+#endif
+
+/**
+ * container_off_var - get offset of a field in enclosing structure
+ * @container_var: a pointer to a container structure
+ * @member: the name of a member within the structure.
+ *
+ * Given (any) pointer to a structure and a its member name, this
+ * macro does pointer subtraction to return offset of member in a
+ * structure memory layout.
+ *
+ */
+#if HAVE_TYPEOF
+#define container_off_var(var, member) \
+ container_off(typeof(*var), member)
+#else
+#define container_off_var(var, member) \
+ ((const char *)&(var)->member - (const char *)(var))
+#endif
+
+#endif /* CCAN_CONTAINER_OF_H */