From 4d3b1067234e6ada466e6bd5588b50f02d947b55 Mon Sep 17 00:00:00 2001
From: "Michael D. Lowis" <mike@mdlowis.com>
Date: Fri, 5 Jun 2015 21:59:38 -0400
Subject: [PATCH] Added refcounting functionality

---
 source/libc.h     | 18 ++++++++--------
 source/refcount.c | 52 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 61 insertions(+), 9 deletions(-)
 create mode 100644 source/refcount.c

diff --git a/source/libc.h b/source/libc.h
index d24acdb..21947cd 100644
--- a/source/libc.h
+++ b/source/libc.h
@@ -23,6 +23,11 @@
 #define nelem(x) (sizeof(x)/sizeof((x)[0]))
 #endif
 
+#ifndef container_of
+#define container_of(obj, type, member) \
+    (type*)((uintptr_t)obj - offsetof(type, member))
+#endif
+
 /*
  * Assertions
  */
@@ -58,17 +63,12 @@ int cistrcmp(char*, char*);
 char* cistrstr(char*, char*);
 int tokenize(char*, char**, int);
 
+void* refallocate(size_t);
+void* refobject(size_t,void (*)(void*));
 void* refretain(void*);
 void refrelease(void*);
-void refcount(void*);
-static inline void __refreplace(void** var, void* val)
-{
-    void* doomed = *var;
-    *var = val;
-    refrelease(doomed);
-}
-#define refreplace(var, val) \
-    __refreplace((void**)var, val);
+size_t refcount(void*);
+void refreplace(void** var, void* val);
 
 /*
  * Rune Definitions and Routines
diff --git a/source/refcount.c b/source/refcount.c
new file mode 100644
index 0000000..d665600
--- /dev/null
+++ b/source/refcount.c
@@ -0,0 +1,52 @@
+#include "libc.h"
+
+typedef struct obj_t {
+    uintptr_t refcount;
+    void (*destruct)(void*);
+    uint8_t data[];
+} obj_t;
+
+void* refallocate(size_t sz)
+{
+    return refobject(sz, nil);
+}
+
+void* refobject(size_t sz, void (*destruct)(void*))
+{
+    obj_t* object = (obj_t*)malloc(sizeof(obj_t) + sz);
+    object->refcount = 1;
+    object->destruct = destruct;
+    return &(object->data[0]);
+}
+
+void* refretain(void* obj)
+{
+    obj_t* object = container_of(obj, obj_t, data);
+    object->refcount++;
+    return obj;
+}
+
+void refrelease(void* obj)
+{
+    obj_t* object = container_of(obj, obj_t, data);
+    object->refcount--;
+    if (object->refcount == 0) {
+        if (nil != object->destruct)
+            object->destruct(obj);
+        free(object);
+    }
+}
+
+size_t refcount(void* obj)
+{
+    obj_t* object = container_of(obj, obj_t, data);
+    return object->refcount;
+}
+
+void refreplace(void** var, void* val)
+{
+    void* deadite = *var;
+    *var = val;
+    refrelease(deadite);
+}
+
-- 
2.54.0