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#include "hybbx/kiss.h"
#include <string.h>
void hybbx_kiss_decoder_init(hybbx_kiss_decoder_t *dec)
{
if (dec == NULL) {
return;
}
memset(dec, 0, sizeof(*dec));
}
static void deliver_frame(hybbx_kiss_decoder_t *dec,
hybbx_kiss_frame_cb cb, void *userdata)
{
uint8_t port;
const uint8_t *payload;
size_t payload_len;
if (dec->len < 1) {
return;
}
port = (uint8_t)((dec->buf[0] >> 4) & 0x0Fu);
payload = dec->buf + 1;
payload_len = dec->len - 1;
if (cb != NULL) {
cb(port, payload, payload_len, userdata);
}
}
void hybbx_kiss_decoder_feed(hybbx_kiss_decoder_t *dec,
const uint8_t *data, size_t len,
hybbx_kiss_frame_cb cb, void *userdata)
{
size_t i;
if (dec == NULL || data == NULL) {
return;
}
for (i = 0; i < len; i++) {
uint8_t byte = data[i];
if (byte == HYBBX_KISS_FEND) {
if (dec->in_frame && dec->len > 0) {
deliver_frame(dec, cb, userdata);
}
dec->in_frame = 1;
dec->escape = 0;
dec->len = 0;
continue;
}
if (!dec->in_frame) {
continue;
}
if (dec->escape) {
if (byte == HYBBX_KISS_TFEND) {
byte = HYBBX_KISS_FEND;
} else if (byte == HYBBX_KISS_TFESC) {
byte = HYBBX_KISS_FESC;
}
dec->escape = 0;
} else if (byte == HYBBX_KISS_FESC) {
dec->escape = 1;
continue;
}
if (dec->len >= HYBBX_KISS_MAX_FRAME) {
dec->len = 0;
dec->in_frame = 0;
continue;
}
dec->buf[dec->len++] = byte;
}
}
static size_t kiss_write_byte(uint8_t byte, uint8_t *out, size_t out_cap, size_t pos)
{
if (pos + 1 > out_cap) {
return 0;
}
if (byte == HYBBX_KISS_FEND) {
if (pos + 2 > out_cap) {
return 0;
}
out[pos++] = HYBBX_KISS_FESC;
out[pos++] = HYBBX_KISS_TFEND;
return pos;
}
if (byte == HYBBX_KISS_FESC) {
if (pos + 2 > out_cap) {
return 0;
}
out[pos++] = HYBBX_KISS_FESC;
out[pos++] = HYBBX_KISS_TFESC;
return pos;
}
out[pos++] = byte;
return pos;
}
size_t hybbx_kiss_encode(uint8_t port, hybbx_kiss_command_t cmd,
const uint8_t *payload, size_t payload_len,
uint8_t *out, size_t out_cap)
{
size_t pos = 0;
uint8_t cmd_byte;
size_t i;
if (out == NULL || out_cap < 3) {
return 0;
}
if (payload_len > 0 && payload == NULL) {
return 0;
}
if (payload_len + 4 > out_cap) {
return 0;
}
out[pos++] = HYBBX_KISS_FEND;
cmd_byte = (uint8_t)(((port & 0x0Fu) << 4) | ((uint8_t)cmd & 0x0Fu));
pos = kiss_write_byte(cmd_byte, out, out_cap, pos);
if (pos == 0) {
return 0;
}
for (i = 0; i < payload_len; i++) {
pos = kiss_write_byte(payload[i], out, out_cap, pos);
if (pos == 0) {
return 0;
}
}
if (pos + 1 > out_cap) {
return 0;
}
out[pos++] = HYBBX_KISS_FEND;
return pos;
}
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