From febd43c9870a0305f0d38b4c3ff87b54f5f18fb1 Mon Sep 17 00:00:00 2001
From: Alex Kotov <kotovalexarian@gmail.com>
Date: Mon, 27 Jun 2022 14:08:32 +0300
Subject: [PATCH] Add macro `KERNAUX_CONTAINER_OF` (#100)

* Add macro KERNAUX_CONTAINER_OF
* Add includes
* Add "examples/macro_container_of"
---
 .gitignore                    |  1 +
 examples/Makefile.am          |  8 ++++++++
 examples/generic_file.c       |  3 +++
 examples/macro_container_of.c | 33 +++++++++++++++++++++++++++++++++
 include/kernaux/macro.h       |  6 ++++++
 src/free_list.c               |  7 +++----
 6 files changed, 54 insertions(+), 4 deletions(-)
 create mode 100644 examples/macro_container_of.c

diff --git a/.gitignore b/.gitignore
index 2eb78b1..a98493d 100644
--- a/.gitignore
+++ b/.gitignore
@@ -111,6 +111,7 @@
 /examples/generic_file
 /examples/generic_malloc
 /examples/generic_mutex
+/examples/macro_container_of
 /examples/memmap
 /examples/ntoa
 /examples/panic
diff --git a/examples/Makefile.am b/examples/Makefile.am
index 3d4ce95..a9ce770 100644
--- a/examples/Makefile.am
+++ b/examples/Makefile.am
@@ -45,6 +45,14 @@ TESTS += generic_mutex
 generic_mutex_LDADD = $(top_builddir)/libkernaux.la
 generic_mutex_SOURCES = main.c generic_mutex.c
 
+######################
+# macro_container_of #
+######################
+
+TESTS += macro_container_of
+macro_container_of_LDADD = $(top_builddir)/libkernaux.la
+macro_container_of_SOURCES = main.c macro_container_of.c
+
 ##########
 # memmap #
 ##########
diff --git a/examples/generic_file.c b/examples/generic_file.c
index ee47802..510639e 100644
--- a/examples/generic_file.c
+++ b/examples/generic_file.c
@@ -28,6 +28,9 @@ struct MyFile MyFile_create(char *ptr, size_t size);
 // my_file.c
 //===========
 
+#include <kernaux/generic/file.h>
+#include <stddef.h>
+
 static int MyFile_putc(void *file, unsigned char c);
 
 struct MyFile MyFile_create(char *const ptr, const size_t size)
diff --git a/examples/macro_container_of.c b/examples/macro_container_of.c
new file mode 100644
index 0000000..3c92f3e
--- /dev/null
+++ b/examples/macro_container_of.c
@@ -0,0 +1,33 @@
+#include <kernaux/macro.h>
+
+#include <assert.h>
+
+struct Foo {
+    const char *hello;
+};
+
+struct Bar {
+    unsigned char a;
+    unsigned int b;
+    struct Foo foo;
+    unsigned short c;
+};
+
+static const struct Bar bar = {
+    .a = 143,
+    .b = 820794098,
+    .foo = {
+        .hello = "Hello, World!",
+    },
+    .c = 10981,
+};
+
+void example_main()
+{
+    const struct Bar *const bar_ptr =
+        KERNAUX_CONTAINER_OF(&bar.foo, struct Bar, foo);
+
+    assert(bar_ptr->a == 143);
+    assert(bar_ptr->b == 820794098);
+    assert(bar_ptr->c == 10981);
+}
diff --git a/include/kernaux/macro.h b/include/kernaux/macro.h
index 244748b..be4c3d0 100644
--- a/include/kernaux/macro.h
+++ b/include/kernaux/macro.h
@@ -5,6 +5,12 @@
 extern "C" {
 #endif
 
+#include <stddef.h>
+#include <stdint.h>
+
+#define KERNAUX_CONTAINER_OF(ptr, type, member) \
+    ((type*)((uintptr_t)(ptr) - offsetof(type, member)))
+
 #ifdef KERNAUX_ACCESS_PRIVATE
 #   define KERNAUX_PRIVATE_FIELD(id) id
 #   define KERNAUX_PROTECTED_FIELD(id) id
diff --git a/src/free_list.c b/src/free_list.c
index 9a9024e..c6963ab 100644
--- a/src/free_list.c
+++ b/src/free_list.c
@@ -13,6 +13,7 @@
 #include <kernaux/free_list.h>
 #include <kernaux/generic/malloc.h>
 #include <kernaux/generic/mutex.h>
+#include <kernaux/macro.h>
 
 #include <stddef.h>
 #include <stdint.h>
@@ -22,8 +23,6 @@
 #define MIN_ZONE_SIZE (2 * NODE_HEADER_SIZE)
 #define MIN_SPLIT_SIZE (NODE_HEADER_SIZE + 16)
 
-#define CONTAINER_OF(ptr, type, member) ((type*)((uintptr_t)(ptr) - offsetof(type, member)))
-
 //#define ALIGN_MASK(align) ((align) - 1) // align should be a power of 2
 //#define ALIGN_UP(val, align) (((val) + ALIGN_MASK(align)) & ~ALIGN_MASK(align))
 
@@ -131,7 +130,7 @@ void KernAux_FreeList_free(void *const malloc, void *const ptr)
     LOCK(free_list);
 
     KernAux_FreeList_Node node =
-        CONTAINER_OF(ptr, struct KernAux_FreeList_Node, block);
+        KERNAUX_CONTAINER_OF(ptr, struct KernAux_FreeList_Node, block);
     KernAux_FreeList_Node last_node = NULL;
 
     for (
@@ -216,7 +215,7 @@ void *KernAux_FreeList_realloc(
     LOCK(free_list);
 
     KernAux_FreeList_Node node =
-        CONTAINER_OF(old_ptr, struct KernAux_FreeList_Node, block);
+        KERNAUX_CONTAINER_OF(old_ptr, struct KernAux_FreeList_Node, block);
     const size_t old_size = node->size - NODE_HEADER_SIZE;
 
     void *new_ptr = KernAux_FreeList_malloc(free_list, new_size);