1 files changed, 99 insertions, 0 deletions
diff --git a/roms/ipxe/src/core/refcnt.c b/roms/ipxe/src/core/refcnt.c
new file mode 100644
index 00000000..68a86120
--- /dev/null
+++ b/roms/ipxe/src/core/refcnt.c
@@ -0,0 +1,99 @@
+/*
+ * Copyright (C) 2007 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or any later version.
+ *
+ * This program 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
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+#include <stdlib.h>
+#include <ipxe/refcnt.h>
+
+/** @file
+ *
+ * Reference counting
+ *
+ */
+
+/**
+ * Increment reference count
+ *
+ * @v refcnt		Reference counter, or NULL
+ *
+ * If @c refcnt is NULL, no action is taken.
+ */
+void ref_increment ( struct refcnt *refcnt ) {
+
+	if ( refcnt ) {
+		refcnt->count++;
+		DBGC2 ( refcnt, "REFCNT %p incremented to %d\n",
+			refcnt, refcnt->count );
+	}
+}
+
+/**
+ * Decrement reference count
+ *
+ * @v refcnt		Reference counter, or NULL
+ *
+ * If the reference count decreases below zero, the object's free()
+ * method will be called.
+ *
+ * If @c refcnt is NULL, no action is taken.
+ */
+void ref_decrement ( struct refcnt *refcnt ) {
+
+	if ( ! refcnt )
+		return;
+
+	refcnt->count--;
+	DBGC2 ( refcnt, "REFCNT %p decremented to %d\n",
+		refcnt, refcnt->count );
+
+	if ( refcnt->count >= 0 )
+		return;
+
+	if ( refcnt->count < -1 ) {
+		DBGC ( refcnt, "REFCNT %p decremented too far (%d)!\n",
+		       refcnt, refcnt->count );
+		/* Avoid multiple calls to free(), which typically
+		 * result in memory corruption that is very hard to
+		 * track down.
+		 */
+		return;
+	}
+
+	if ( refcnt->free ) {
+		DBGC ( refcnt, "REFCNT %p being freed via method %p\n",
+		       refcnt, refcnt->free );
+		refcnt->free ( refcnt );
+	} else {
+		DBGC ( refcnt, "REFCNT %p being freed\n", refcnt );
+		free ( refcnt );
+	}
+}
+
+/**
+ * Do not free reference-counted object
+ *
+ * @v refcnt		Reference counter
+ *
+ * This is meant for initializing a reference counter structure in a
+ * statically allocated object.
+ */
+void ref_no_free ( struct refcnt *refcnt __unused ) {
+	/* Do nothing */
+}