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authorFred Sundvik <fsundvik@gmail.com>2016-02-14 15:28:57 +0200
committerFred Sundvik <fsundvik@gmail.com>2016-02-14 15:28:57 +0200
commite8cb6d8023cf2912a08dc1a0a1b108b6dbc429cc (patch)
treee2a6a9110ac13cc4e6608ee3132339fa7d370bab /serial_link/protocol/byte_stuffer.c
parenteefb5b5634e341396fb535f4eeac1323bf716ed0 (diff)
Bytestuffer recv handling of long frames
Diffstat (limited to 'serial_link/protocol/byte_stuffer.c')
-rw-r--r--serial_link/protocol/byte_stuffer.c26
1 files changed, 20 insertions, 6 deletions
diff --git a/serial_link/protocol/byte_stuffer.c b/serial_link/protocol/byte_stuffer.c
index e578f88dc1..cc7afe97ae 100644
--- a/serial_link/protocol/byte_stuffer.c
+++ b/serial_link/protocol/byte_stuffer.c
@@ -24,26 +24,35 @@ SOFTWARE.
#include "protocol/byte_stuffer.h"
#include "protocol/frame_validator.h"
+#include <stdio.h>
// This implements the "Consistent overhead byte stuffing protocol"
// https://en.wikipedia.org/wiki/Consistent_Overhead_Byte_Stuffing
// http://www.stuartcheshire.org/papers/COBSforToN.pdf
+#define MAX_FRAME_SIZE 1024
+
typedef struct byte_stuffer_state {
uint16_t next_zero;
uint16_t data_pos;
- uint8_t data[256];
+ bool long_frame;
+ uint8_t data[MAX_FRAME_SIZE];
}byte_stuffer_state_t;
void init_byte_stuffer_state(byte_stuffer_state_t* state) {
state->next_zero = 0;
state->data_pos = 0;
+ state->long_frame = false;
+}
+
+static void start_frame(byte_stuffer_state_t* state, uint8_t data) {
}
void recv_byte(byte_stuffer_state_t* state, uint8_t data) {
// Start of a new frame
if (state->next_zero == 0) {
state->next_zero = data;
+ state->long_frame = data == 0xFF;
state->data_pos = 0;
return;
}
@@ -56,15 +65,20 @@ void recv_byte(byte_stuffer_state_t* state, uint8_t data) {
}
else {
// The frame is invalid, so reset
- state->next_zero = 0;
- state->data_pos = 0;
+ init_byte_stuffer_state(state);
}
}
else {
if (state->next_zero == 0) {
- // Special case for zeroes
- state->next_zero = data;
- state->data[state->data_pos++] = 0;
+ if (state->long_frame) {
+ state->next_zero = data;
+ state->long_frame = data == 0xFF;
+ }
+ else {
+ // Special case for zeroes
+ state->next_zero = data;
+ state->data[state->data_pos++] = 0;
+ }
}
else {
state->data[state->data_pos++] = data;