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/*
* Copyright (c) 2005 Arch Rock Corporation
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* - 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.
* - Neither the name of the Arch Rock Corporation 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 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 THE
* ARCHED ROCK 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)
* 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
*
*/
/**
* The ReadStream interface is intended for buffered high data rate
* reading, usually from sensor devices. The type of the values being
* read is given as a template argument.
*
* <p> To use this interface, allocate one or more buffers in your own
* space. Then, call postBuffer to pass these buffers into the
* device. Call read() to begin the sampling process. The buffers will
* be filled in the order originally posted, and a bufferDone() event
* will be signaled once each buffer has been filled with data. At any
* time while the read() is running, you may post new buffers to be
* filled. If the lower layer finishes signaling readDone() and then
* finds that no more buffers have been posted, it will consider the
* read to be finished, and signal readDone().
*
* <p>
* See TEP114 - SIDs: Source and Sink Independent Drivers for details.
*
* @param val_t the type of the object that will be returned
*
* @author Gilman Tolle <gtolle@archrock.com>
* @version $Revision: 1.5 $ $Date: 2008-06-04 03:00:31 $
*/
interface ReadStream<val_t> {
/**
* Passes a buffer to the device, and indicates how many values
* should be placed into the buffer. Make sure your count doesn't
* overrun the buffer.
*
* @param 'val_t* COUNT(count) buf' a pointer to the buffer
* @param count the number of values the buffer should hold
*
* @return SUCCESS if the post was successful
*/
command error_t postBuffer(val_t* buf, uint16_t count);
/**
* Directs the device to start filling buffers by sampling with the
* specified period.
*
* @param usPeriod the between-sample period in microseconds
*
* @return SUCCESS if the reading process began
*/
command error_t read(uint32_t usPeriod);
/**
* Signalled when a previously posted buffer has been filled by the
* device. In the event of a read error, result will not equal
* SUCCESS, and the buffer will be filled with zeroes.
*
* @param result SUCCESS if the buffer was filled without errors
* @param 'val_t* COUNT(count) buf' a pointer to the buffer that has been filled
* @param count the number of values actually read
*/
event void bufferDone(error_t result,
val_t* buf, uint16_t count);
/**
* Signalled when a buffer has been filled but no more buffers have
* been posted. In the event of a read error, all previously posted
* buffers will have their bufferDone() event signalled, and then
* this event will be signalled with a non-SUCCESS argument.
*
* @param result SUCCESS if all buffers were filled without errors
* @param usActualPeriod Actual sampling period used - may be different
* from period requested at read time. Undefined if result != SUCCESS.
*/
event void readDone(error_t result, uint32_t usActualPeriod);
}
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