[PATCH] added callback framework

[root]

---
 com32/include/syslinux/callback.h |   67 ++++++++++++++++++++++++++++++++
 com32/lib/syslinux/callback.c     |   76 +++++++++++++++++++++++++++++++++++++
 2 files changed, 143 insertions(+), 0 deletions(-)
 create mode 100644 com32/include/syslinux/callback.h
 create mode 100644 com32/lib/syslinux/callback.c

diff --git a/com32/include/syslinux/callback.h b/com32/include/syslinux/callback.h
new file mode 100644
index 0000000..40de8f4
--- /dev/null
+++ b/com32/include/syslinux/callback.h
@@ -0,0 +1,67 @@
+/* ----------------------------------------------------------------------- *
+ *
+ *   Copyright 2007-2008 H. Peter Anvin - All Rights Reserved
+ *
+ *   Permission is hereby granted, free of charge, to any person
+ *   obtaining a copy of this software and associated documentation
+ *   files (the "Software"), to deal in the Software without
+ *   restriction, including without limitation the rights to use,
+ *   copy, modify, merge, publish, distribute, sublicense, and/or
+ *   sell copies of the Software, and to permit persons to whom
+ *   the Software is furnished to do so, subject to the following
+ *   conditions:
+ *
+ *   The above copyright notice and this permission notice shall
+ *   be included in all copies or substantial portions of the Software.
+ *
+ *   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ *   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+ *   OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ *   NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+ *   HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ *   WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ *   FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ *   OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * syslinux/callback.h
+ *
+ * sensible callback framework
+ */
+
+#ifndef _SYSLINUX_CALLBACK_H
+#define _SYSLINUX_CALLBACK_H
+
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <inttypes.h>
+#include <assert.h>
+
+struct callback_record;
+
+typedef void (*callback_t)(const void *rarg, va_list ap);
+
+#define DECLARE_CALLBACK(name) 		\
+struct callback_record name = { 	\
+	.function 	= NULL,		\
+	.next		= &name,	\
+	.prev		= &name,	\
+}
+
+
+struct callback_record  {
+  callback_t function;
+  struct callback_record *next;
+  struct callback_record *prev;
+  const void *rarg;
+};
+
+
+struct callback_record* register_callback(struct callback_record *head, callback_t callback, const void *rarg);
+int unregister_callback(struct callback_record *cb);
+int invoke_callbacks(struct callback_record *head, ...);
+
+#endif /* _SYSLINUX_CALLBACK_H */
diff --git a/com32/lib/syslinux/callback.c b/com32/lib/syslinux/callback.c
new file mode 100644
index 0000000..60d6025
--- /dev/null
+++ b/com32/lib/syslinux/callback.c
@@ -0,0 +1,76 @@
+/* ----------------------------------------------------------------------- *
+ *
+ *   Copyright 2007-2008 H. Peter Anvin - All Rights Reserved
+ *
+ *   Permission is hereby granted, free of charge, to any person
+ *   obtaining a copy of this software and associated documentation
+ *   files (the "Software"), to deal in the Software without
+ *   restriction, including without limitation the rights to use,
+ *   copy, modify, merge, publish, distribute, sublicense, and/or
+ *   sell copies of the Software, and to permit persons to whom
+ *   the Software is furnished to do so, subject to the following
+ *   conditions:
+ *
+ *   The above copyright notice and this permission notice shall
+ *   be included in all copies or substantial portions of the Software.
+ *
+ *   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ *   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+ *   OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ *   NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+ *   HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ *   WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ *   FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ *   OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * syslinux/callback.c
+ *
+ * sensible callback framework
+ */
+
+#include <syslinux/callback.h>
+
+struct callback_record* register_callback(struct callback_record *head, callback_t callback, const void *rarg)
+{
+    struct callback_record *new;
+
+    new = malloc(sizeof(struct callback_record));
+    if (!new)
+        return NULL;
+
+    new->function = callback;
+    new->rarg = rarg;
+    new->next = head->next;
+    new->prev = head;
+    head->next->prev = new;
+    head->next = new;
+    return new;
+}
+
+int unregister_callback(struct callback_record *cb)
+{
+    cb->next->prev = cb->prev;
+    cb->prev->next = cb->next;
+    free(cb);
+    return 0;
+}
+
+int invoke_callbacks(struct callback_record *head, ...)
+{
+   va_list ap;
+   struct callback_record *curr;
+
+   curr = head;
+   do {
+       if (curr->function) {
+           va_start(ap, head);
+           curr->function(curr->rarg, ap);
+           va_end(ap);
+       }
+       curr = curr->next;
+   } while(curr != head);
+   return 0;
+}
-- 
1.6.0.2