Diff: lc-switch.h

Revision:

0:edab293d7652

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lc-switch.h	Tue Nov 30 22:19:29 2010 +0000
@@ -0,0 +1,76 @@
+/*
+ * Copyright (c) 2004-2005, Swedish Institute of Computer Science.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the Institute nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * This file is part of the Contiki operating system.
+ *
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ * $Id: lc-switch.h,v 1.4 2006/06/03 11:29:43 adam Exp $
+ */
+
+/**
+ * \addtogroup lc
+ * @{
+ */
+
+/**
+ * \file
+ * Implementation of local continuations based on switch() statment
+ * \author Adam Dunkels <adam@sics.se>
+ *
+ * This implementation of local continuations uses the C switch()
+ * statement to resume execution of a function somewhere inside the
+ * function's body. The implementation is based on the fact that
+ * switch() statements are able to jump directly into the bodies of
+ * control structures such as if() or while() statmenets.
+ *
+ * This implementation borrows heavily from Simon Tatham's coroutines
+ * implementation in C:
+ * http://www.chiark.greenend.org.uk/~sgtatham/coroutines.html
+ */
+
+#ifndef __LC_SWITCH_H__
+#define __LC_SWITCH_H__
+
+/* WARNING! lc implementation using switch() does not work if an
+   LC_SET() is done within another switch() statement! */
+
+/** \hideinitializer */
+typedef unsigned short lc_t;
+
+#define LC_INIT(s) s = 0;
+
+#define LC_RESUME(s) switch(s) { case 0:
+
+#define LC_SET(s) s = __LINE__; case __LINE__:
+
+#define LC_END(s) }
+
+#endif /* __LC_SWITCH_H__ */
+
+/** @} */