lc-switch.h 2.7 KB

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  1. /*
  2. * Copyright (c) 2004-2005, Swedish Institute of Computer Science.
  3. * All rights reserved.
  4. *
  5. * Redistribution and use in source and binary forms, with or without
  6. * modification, are permitted provided that the following conditions
  7. * are met:
  8. * 1. Redistributions of source code must retain the above copyright
  9. * notice, this list of conditions and the following disclaimer.
  10. * 2. Redistributions in binary form must reproduce the above copyright
  11. * notice, this list of conditions and the following disclaimer in the
  12. * documentation and/or other materials provided with the distribution.
  13. * 3. Neither the name of the Institute nor the names of its contributors
  14. * may be used to endorse or promote products derived from this software
  15. * without specific prior written permission.
  16. *
  17. * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  18. * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19. * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20. * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  21. * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22. * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23. * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24. * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25. * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26. * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27. * SUCH DAMAGE.
  28. *
  29. * This file is part of the Contiki operating system.
  30. *
  31. * Author: Adam Dunkels <adam@sics.se>
  32. *
  33. * $Id: lc-switch.h,v 1.4 2006/06/03 11:29:43 adam Exp $
  34. */
  35. /**
  36. * \addtogroup lc
  37. * @{
  38. */
  39. /**
  40. * \file
  41. * Implementation of local continuations based on switch() statment
  42. * \author Adam Dunkels <adam@sics.se>
  43. *
  44. * This implementation of local continuations uses the C switch()
  45. * statement to resume execution of a function somewhere inside the
  46. * function's body. The implementation is based on the fact that
  47. * switch() statements are able to jump directly into the bodies of
  48. * control structures such as if() or while() statmenets.
  49. *
  50. * This implementation borrows heavily from Simon Tatham's coroutines
  51. * implementation in C:
  52. * http://www.chiark.greenend.org.uk/~sgtatham/coroutines.html
  53. */
  54. #ifndef __LC_SWITCH_H__
  55. #define __LC_SWITCH_H__
  56. /* WARNING! lc implementation using switch() does not work if an
  57. LC_SET() is done within another switch() statement! */
  58. /** \hideinitializer */
  59. typedef unsigned short lc_t;
  60. #define LC_INIT(s) s = 0;
  61. #define LC_RESUME(s) switch(s) { case 0:
  62. #define LC_SET(s) s = __LINE__; case __LINE__:
  63. #define LC_END(s) }
  64. #endif /* __LC_SWITCH_H__ */
  65. /** @} */