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S.BUS parser: Empty complete buffer

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Lorenz Meier
2015-12-07 11:41:00 +01:00
parent f8ea18909e
commit ec3282a925
1 changed files with 43 additions and 35 deletions
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src/lib/rc/sbus.c
+43 -35
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@@ -46,6 +46,8 @@
#include "sbus.h"
#include <drivers/drv_hrt.h>
#define SBUS_START_SYMBOL 0x0f
#define SBUS_FRAME_SIZE 25
#define SBUS_INPUT_CHANNELS 16
#define SBUS_FLAGS_BYTE 23
@@ -194,51 +196,57 @@ sbus_input(int sbus_fd, uint16_t *values, uint16_t *num_values, bool *sbus_fails
/*
* If we timed out, reset the decoder
*/
if ((now - last_rx_time) > 4000) {
if ((now - last_rx_time) > 6000) {
if (partial_frame_count > 0) {
sbus_frame_drops++;
partial_frame_count = 0;
}
}
/*
* Fetch bytes, but no more than we would need to complete
* the current frame.
*/
ret = read(sbus_fd, &frame[partial_frame_count], SBUS_FRAME_SIZE - partial_frame_count);
bool decode_success = false;
/* if the read failed for any reason, just give up here */
if (ret < 1) {
return false;
}
do {
/*
* Fetch bytes, but no more than we would need to complete
* the current frame.
*/
ret = read(sbus_fd, &frame[partial_frame_count], SBUS_FRAME_SIZE - partial_frame_count);
/* if the first byte of the frame is not the start symbol, give up instantly */
if (frame[0] != SBUS_START_SYMBOL) {
sbus_frame_drops++;
/* if the read failed for any reason, just give up here */
if (ret < 1) {
continue;
}
last_rx_time = now;
/* if the first byte of the frame is not the start symbol, give up instantly */
if (frame[0] != SBUS_START_SYMBOL) {
sbus_frame_drops++;
partial_frame_count = 0;
continue;
}
/*
* Add bytes to the current frame
*/
partial_frame_count += ret;
/*
* If we don't have a full frame, return
*/
if (partial_frame_count < SBUS_FRAME_SIZE) {
continue;
}
/*
* Great, it looks like we might have a frame. Go ahead and
* decode it.
*/
partial_frame_count = 0;
return false;
}
decode_success = decode_success || sbus_decode(now, values, num_values, sbus_failsafe, sbus_frame_drop, max_channels);
} while (ret > 0);
last_rx_time = now;
/*
* Add bytes to the current frame
*/
partial_frame_count += ret;
/*
* If we don't have a full frame, return
*/
if (partial_frame_count < SBUS_FRAME_SIZE) {
return false;
}
/*
* Great, it looks like we might have a frame. Go ahead and
* decode it.
*/
partial_frame_count = 0;
return sbus_decode(now, values, num_values, sbus_failsafe, sbus_frame_drop, max_channels);
return decode_success;
}
/*