blockingreadstreamp.nc

tinyos2.0版本驱动

/*
 * Copyright (c) 2008 Stanford University.
 * All rights reserved.
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 * modification, are permitted provided that the following conditions
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 * - Redistributions of source code must retain the above copyright
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 * - Redistributions in binary form must reproduce the above copyright
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 *   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 COPYRIGHT HOLDERS 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 STANFORD
 * UNIVERSITY OR ITS 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)
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 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
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 */

/**
 * @author Kevin Klues <[e-mail]>
 */

generic module BlockingReadStreamP() {
  provides {
    interface Init;
    interface BlockingReadStream<uint16_t> as BlockingReadStream[uint8_t streamClient];
  }
  uses {
    interface ReadStream<uint16_t> as ReadStream[uint8_t streamClient];
    
    interface SystemCall;
    interface SystemCallQueue;
  }
}
implementation {

  typedef struct readstream_params {
    uint32_t* usPeriod;
    uint16_t* buf;
    uint16_t* count;
    error_t   error;
  } readstream_params_t;

  syscall_queue_t readstream_queue;
  
  command error_t Init.init() {
    call SystemCallQueue.init(&readstream_queue);
    return SUCCESS;
  }
  
  /**************************** ReadStream ********************************/
  void readStreamTask(syscall_t* s) {
    readstream_params_t* p = s->params;
    p->error = call ReadStream.postBuffer[s->id](p->buf, *(p->count));
    if(p->error == SUCCESS)
      p->error = call ReadStream.read[s->id](*(p->usPeriod));
    if(p->error != SUCCESS)
      call SystemCall.finish(s);
  }
  
  command error_t BlockingReadStream.read[uint8_t id](uint32_t* usPeriod, uint16_t* buf, uint16_t count) {
    syscall_t s;
    readstream_params_t p;
    atomic {
      if(call SystemCallQueue.find(&readstream_queue, id) != NULL)
        return EBUSY;
      call SystemCallQueue.enqueue(&readstream_queue, &s);
    }
    
    p.usPeriod = usPeriod;
    p.buf = buf;
    p.count = &count;
    call SystemCall.start(&readStreamTask, &s, id, &p);
    
    atomic {
      call SystemCallQueue.remove(&readstream_queue, &s);
      return p.error;
    }
  }
  
  event void ReadStream.bufferDone[uint8_t id](error_t result, 
			 uint16_t* buf, uint16_t count) {
    //Should never get here!!!!!!
  }
			 
  event void ReadStream.readDone[uint8_t id](error_t result, uint32_t usPeriod) {
    syscall_t* s = call SystemCallQueue.find(&readstream_queue, id);
    readstream_params_t* p = s->params;
    *(p->usPeriod) = usPeriod;
    p->error = result;
    call SystemCall.finish(s);  
  }
  default command error_t ReadStream.read[uint8_t id](uint32_t usPeriod) { return FAIL; }
}