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Diffstat (limited to 'apps/systemlib/hx_stream.h')
-rw-r--r-- | apps/systemlib/hx_stream.h | 121 |
1 files changed, 121 insertions, 0 deletions
diff --git a/apps/systemlib/hx_stream.h b/apps/systemlib/hx_stream.h new file mode 100644 index 000000000..591bb1291 --- /dev/null +++ b/apps/systemlib/hx_stream.h @@ -0,0 +1,121 @@ +/**************************************************************************** + * + * Copyright (C) 2012 PX4 Development Team. 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 PX4 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 + * COPYRIGHT OWNER 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. + * + ****************************************************************************/ + +/** + * @file A simple serial line framing protocol based on HDLC + * with 32-bit CRC protection. + */ + +#ifndef _SYSTEMLIB_HX_STREAM_H +#define _SYSTEMLIB_HX_STREAM_H + +#include <sys/types.h> + +#include "perf_counter.h" + +struct hx_stream; +typedef struct hx_stream *hx_stream_t; + +#define HX_STREAM_MAX_FRAME 64 + +typedef void (* hx_stream_rx_callback)(void *arg, const void *data, size_t length); + +__BEGIN_DECLS + +/** + * Allocate a new hx_stream object. + * + * @param fd The file handle over which the protocol will + * communicate. + * @param callback Called when a frame is received. + * @param callback_arg Passed to the callback. + * @return A handle to the stream, or NULL if memory could + * not be allocated. + */ +__EXPORT extern hx_stream_t hx_stream_init(int fd, + hx_stream_rx_callback callback, + void *arg); + +/** + * Free a hx_stream object. + * + * @param stream A handle returned from hx_stream_init. + */ +__EXPORT extern void hx_stream_free(hx_stream_t stream); + +/** + * Set performance counters for the stream. + * + * Any counter may be set to NULL to disable counting that datum. + * + * @param tx_frames Counter for transmitted frames. + * @param rx_frames Counter for received frames. + * @param rx_errors Counter for short and corrupt received frames. + */ +__EXPORT extern void hx_stream_set_counters(hx_stream_t stream, + perf_counter_t tx_frames, + perf_counter_t rx_frames, + perf_counter_t rx_errors); + +/** + * Send a frame. + * + * This function will block until all frame bytes are sent if + * the descriptor passed to hx_stream_init is marked blocking, + * otherwise it will return -1 (but may transmit a + * runt frame at the same time). + * + * @todo Handling of non-blocking streams needs to be better. + * + * @param stream A handle returned from hx_stream_init. + * @param data Pointer to the data to send. + * @param count The number of bytes to send. + * @return Zero on success, nonzero with errno + * set on error. + */ +__EXPORT extern int hx_stream_send(hx_stream_t stream, + const void *data, + size_t count); + +/** + * Handle a byte from the stream. + * + * @param stream A handle returned from hx_stream_init. + * @param c The character to process. + */ +__EXPORT extern void hx_stream_rx(hx_stream_t stream, + uint8_t c); + +__END_DECLS + +#endif |