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#include "sixpack.h"
#include <string.h>
void hybbx_sixpack_decoder_init(hybbx_sixpack_decoder_t *dec)
{
if (dec == NULL) {
return;
}
memset(dec, 0, sizeof(*dec));
}
static void sixpack_reset(hybbx_sixpack_decoder_t *dec)
{
dec->len = 0;
dec->count = 0;
dec->checksum = 0;
dec->in_frame = 0;
}
static void sixpack_deliver(hybbx_sixpack_decoder_t *dec,
hybbx_sixpack_frame_cb cb, void *userdata)
{
if (cb != NULL && dec->len > 0) {
cb(dec->buf, dec->len, userdata);
}
sixpack_reset(dec);
}
void hybbx_sixpack_decoder_feed(hybbx_sixpack_decoder_t *dec,
const uint8_t *data, size_t len,
hybbx_sixpack_frame_cb cb, void *userdata)
{
size_t i;
if (dec == NULL || data == NULL) {
return;
}
for (i = 0; i < len; i++) {
uint8_t raw = data[i];
uint8_t byte = raw;
if (!dec->in_frame) {
if (raw == HYBBX_SIXPACK_LEAD) {
dec->in_frame = 1;
dec->len = 0;
dec->count = 0;
dec->checksum = 0;
}
continue;
}
if (dec->count == 0) {
dec->count = raw;
dec->checksum = raw;
continue;
}
dec->count--;
dec->checksum = (uint8_t)(dec->checksum + raw);
if (raw < 0x30u) {
byte = (uint8_t)(raw + 0x40u);
}
if (dec->count > 0) {
if (dec->len >= HYBBX_KISS_MAX_FRAME) {
sixpack_reset(dec);
continue;
}
dec->buf[dec->len++] = byte;
continue;
}
if (dec->checksum == 0) {
sixpack_deliver(dec, cb, userdata);
} else {
sixpack_reset(dec);
}
}
}
static size_t sixpack_write_encoded(uint8_t byte, uint8_t *out, size_t out_cap,
size_t pos)
{
if (byte < 0x30u) {
if (pos + 1 > out_cap) {
return 0;
}
out[pos++] = (uint8_t)(byte + 0x40u);
return pos;
}
if (pos + 1 > out_cap) {
return 0;
}
out[pos++] = byte;
return pos;
}
size_t hybbx_sixpack_encode(const uint8_t *frame, size_t frame_len,
uint8_t *out, size_t out_cap)
{
uint8_t scratch[HYBBX_KISS_MAX_FRAME + 4];
size_t enc_len = 0;
size_t i;
uint8_t count;
uint8_t sum;
size_t pos = 0;
if (frame == NULL || out == NULL || frame_len == 0 ||
frame_len > HYBBX_KISS_MAX_FRAME) {
return 0;
}
for (i = 0; i < frame_len; i++) {
enc_len = sixpack_write_encoded(frame[i], scratch, sizeof(scratch),
enc_len);
if (enc_len == 0) {
return 0;
}
}
if (enc_len + 4 > out_cap || enc_len + 1 > 255) {
return 0;
}
count = (uint8_t)(enc_len + 1);
sum = count;
for (i = 0; i < enc_len; i++) {
sum = (uint8_t)(sum + scratch[i]);
}
out[pos++] = HYBBX_SIXPACK_LEAD;
out[pos++] = count;
for (i = 0; i < enc_len; i++) {
out[pos++] = scratch[i];
}
out[pos++] = (uint8_t)(0x100u - (unsigned)sum);
return pos;
}
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