LUFA/Drivers/USB/HighLevel/StreamCallbacks.h

   1 /*
   2              LUFA Library
   3      Copyright (C) Dean Camera, 2009.
   4
   5   dean [at] fourwalledcubicle [dot] com
   6       www.fourwalledcubicle.com
   7 */
   8
   9 /*
  10   Copyright 2009  Dean Camera (dean [at] fourwalledcubicle [dot] com)
  11
  12   Permission to use, copy, modify, and distribute this software
  13   and its documentation for any purpose and without fee is hereby
  14   granted, provided that the above copyright notice appear in all
  15   copies and that both that the copyright notice and this
  16   permission notice and warranty disclaimer appear in supporting
  17   documentation, and that the name of the author not be used in
  18   advertising or publicity pertaining to distribution of the
  19   software without specific, written prior permission.
  20
  21   The author disclaim all warranties with regard to this
  22   software, including all implied warranties of merchantability
  23   and fitness.  In no event shall the author be liable for any
  24   special, indirect or consequential damages or any damages
  25   whatsoever resulting from loss of use, data or profits, whether
  26   in an action of contract, negligence or other tortious action,
  27   arising out of or in connection with the use or performance of
  28   this software.
  29 */
  30
  31 /** \file
  32  *
  33  *  Macros and enums for the stream callback routines in Endpoint.h and Pipe.c. This module contains the
  34  *  code required to easily set up stream callback functions which can be used to force early abort of a
  35  *  stream read/write process.
  36  */
  37
  38 #ifndef __STREAMCALLBACK_H__
  39 #define __STREAMCALLBACK_H__
  40
  41         /* Public Interface - May be used in end-application: */
  42                 /* Macros: */
  43                         /** Creates a prototype for or begins a stream callback routine. Stream callback routines are small
  44                          *  routines which are executed during stream read or writes (if the callback-enabled versions of
  45                          *  these functions are used) which allow the user application to abort the transfer when certain
  46                          *  arbitrary conditions are met.
  47                          *
  48                          *  Stream callback functions should return a value from the StreamCallback_Return_ErrorCodes_t
  49                          *  enum.
  50                          *
  51                          *  Usage Example (Device Endpoint, but applicable for Host Pipes also):
  52                          *  \code
  53                          *  STREAM_CALLBACK(GlobalNotSet); // Callback Prototype
  54                          *
  55                          *  STREAM_CALLBACK(GlobalNotSet)
  56                          *  {
  57                          *     if (MyGlobal == false)
  58                          *         return ENDPOINT_STREAMCALLBACK_Continue;
  59                          *     else
  60                          *         return ENDPOINT_STREAMCALLBACK_Abort;
  61                          *  }
  62                          *
  63                          *  //...
  64                          *  // Inside some routine:
  65                          *  if (Endpoint_Write_Stream_LE(DataBuffer, sizeof(DataBuffer), GlobalNotSet) ==
  66                          *                               ENDPOINT_RWSTREAM_ERROR_CallbackAborted)
  67                          *  {
  68                          *      // Do something when the callback aborted the transfer early
  69                          *  }
  70                          *  \endcode
  71                          */
  72                         #define STREAM_CALLBACK(name) uint8_t name (void)
  73
  74                         /** Used with the Endpoint and Pipe stream functions as the callback function parameter, indicating that the stream
  75                          *  call has no callback function to be called between USB packets.
  76                          */
  77                         #define NO_STREAM_CALLBACK    NULL
  78
  79                 /* Enums: */
  80                         /** Enum for the possible error return codes of a stream callback function */
  81                         enum StreamCallback_Return_ErrorCodes_t
  82                         {
  83                                 STREAMCALLBACK_Continue            = 0, /**< Continue sending or receiving the stream. */
  84                                 STREAMCALLBACK_Abort               = 1, /**< Abort the stream send or receiving process. */
  85                         };
  86
  87 #endif