Consolidate reference counting code.

3 files changed, 58 insertions, 3 deletions

diff --git a/libdimension/dimension/interior.h b/libdimension/dimension/interior.h
index 88af0b9..76f0a32 100644
--- a/libdimension/dimension/interior.h
+++ b/libdimension/dimension/interior.h
@@ -33,7 +33,7 @@ typedef struct dmnsn_interior {
   void *ptr;
 
   /** @internal Reference count. */
-  unsigned int *refcount;
+  dmnsn_refcount *refcount;
 } dmnsn_interior;
 
 /**
diff --git a/libdimension/dimension/refcount.h b/libdimension/dimension/refcount.h
new file mode 100644
index 0000000..14f31ab
--- /dev/null
+++ b/libdimension/dimension/refcount.h
@@ -0,0 +1,55 @@
+/*************************************************************************
+ * Copyright (C) 2011 Tavian Barnes <tavianator@tavianator.com>          *
+ *                                                                       *
+ * This file is part of The Dimension Library.                           *
+ *                                                                       *
+ * The Dimension Library is free software; you can redistribute it and/  *
+ * or modify it under the terms of the GNU Lesser General Public License *
+ * as published by the Free Software Foundation; either version 3 of the *
+ * License, or (at your option) any later version.                       *
+ *                                                                       *
+ * The Dimension Library is distributed in the hope that it will be      *
+ * useful, but WITHOUT ANY WARRANTY; without even the implied warranty   *
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU  *
+ * Lesser General Public License for more details.                       *
+ *                                                                       *
+ * You should have received a copy of the GNU Lesser General Public      *
+ * License along with this program.  If not, see                         *
+ * <http://www.gnu.org/licenses/>.                                       *
+ *************************************************************************/
+
+/**
+ * @file
+ * Generic reference count implementation.
+ */
+
+/**
+ * Increment a reference count.
+ * @param[in,out] object  The reference-counted object to acquire.
+ */
+#define DMNSN_INCREF(obj) ((void)++(*(obj)->refcount))
+
+/**
+ * Decrement a reference count.
+ * @param[in,out] object  The reference-counted object to release.
+ * @return Whether the object is now garbage.
+ */
+#define DMNSN_DECREF(obj) (*(obj)->refcount == 0 || --(*(obj)->refcount) == 0)
+
+/**
+ * Reference counter.
+ */
+typedef unsigned int dmnsn_refcount;
+
+/**
+ * Create a reference count.
+ * @return A new reference counter, initialized to zero (a "borrowed" reference,
+ *         which will be garbage-collected the first time it is deleted).
+ */
+dmnsn_refcount *dmnsn_new_refcount(void);
+
+/**
+ * Delete a reference count.  Raises an error if the reference count wasn't
+ * zero.
+ */
+void dmnsn_delete_refcount(dmnsn_refcount *refcount);
diff --git a/libdimension/dimension/texture.h b/libdimension/dimension/texture.h
index 31ab86b..8051c02 100644
--- a/libdimension/dimension/texture.h
+++ b/libdimension/dimension/texture.h
@@ -31,8 +31,8 @@ typedef struct {
   dmnsn_matrix trans;     /**< Transformation matrix. */
   dmnsn_matrix trans_inv; /**< The inverse of the transformation matrix. */
 
-  unsigned int *refcount; /**< @internal Reference count. */
-  bool should_init;       /**< @internal Whether to initialize the texture. */
+  dmnsn_refcount *refcount; /**< @internal Reference count. */
+  bool should_init;         /**< @internal Whether to initialize the texture. */
 } dmnsn_texture;
 
 /**