drashna/qmk_firmware
1
0
Fork 0
Code Activity Actions

Bytestuffer recv handling of long frames

Browse source
This commit is contained in:
Fred Sundvik 2016-02-14 15:28:57 +02:00
parent eefb5b5634
commit e8cb6d8023
2 changed files with 112 additions and 6 deletions
Download patch file Download diff file Expand all files Collapse all files

26
serial_link/protocol/byte_stuffer.c
View file

@ -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;