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slip: implement decoder

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This commit is contained in:
Matthias Ringwald 2016-03-08 11:52:05 +01:00
parent ec94e29f15
commit 4d6feae01a
2 changed files with 149 additions and 23 deletions
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149
src/btstack_slip.c
View File

@ -41,17 +41,36 @@
*/
#include "btstack_slip.h"
#include "btstack_debug.h"
typedef enum {
SLIP_ENCODER_DEFAULT,
SLIP_ENCODER_SEND_0xDC,
SLIP_ENCODER_SEND_0xDD
SLIP_ENCODER_SEND_DC,
SLIP_ENCODER_SEND_DD
} btstack_slip_encoder_state_t;
// h5 slip state machine
typedef enum {
SLIP_DECODER_UNKNOWN = 1,
SLIP_DECODER_ACTIVE,
SLIP_DECODER_X_C0,
SLIP_DECODER_X_DB,
SLIP_DECODER_COMPLETE
} btstack_slip_decoder_state_t;
// encoder
static btstack_slip_encoder_state_t encoder_state;
static const uint8_t * encoder_data;
static uint16_t encoder_len;
// decoder
static btstack_slip_decoder_state_t decoder_state;
static uint8_t * decoder_buffer;
static uint16_t decoder_max_size;
static uint16_t decoder_pos;
// ENCODER
/**
@ -86,38 +105,122 @@ uint8_t btstack_slip_encoder_get_byte(void){
encoder_len++;
switch (next_byte){
case BTSTACK_SLIP_SOF:
encoder_state = SLIP_ENCODER_SEND_0xDC;
encoder_state = SLIP_ENCODER_SEND_DC;
return 0xdb;
case 0xdb:
encoder_state = SLIP_ENCODER_SEND_0xDD;
encoder_state = SLIP_ENCODER_SEND_DD;
return 0xdb;
default:
return next_byte;
}
break;
case SLIP_ENCODER_SEND_0xDC:
case SLIP_ENCODER_SEND_DC:
return 0x0dc;
case SLIP_ENCODER_SEND_0xDD:
case SLIP_ENCODER_SEND_DD:
return 0x0dd;
}
}
#if 0
// Decoder
// format: 0xc0 HEADER PACKER 0xc0
// @param uint8_t header[4]
static void hci_transport_slip_send_frame(const uint8_t * header, const uint8_t * packet, uint16_t packet_size){
// Start of Frame
hci_transport_slip_send_eof();
// Header
hci_transport_slip_send_block(header, 4);
// Packet
hci_transport_slip_send_block(packet, packet_size);
// Endo of frame
hci_transport_slip_send_eof();
static void btstack_slip_decoder_reset(void){
decoder_state = SLIP_DECODER_UNKNOWN;
decoder_pos = 0;
}
static void btstack_slip_decoder_store_byte(uint8_t input){
if (decoder_pos >= decoder_max_size){
log_error("btstack_slip_decoder_store_byte: packet to long");
btstack_slip_decoder_reset();
}
decoder_buffer[decoder_pos++] = input;
}
/**
* @brief Initialise SLIP decoder with buffer
* @param buffer to store received data
* @param max_size of buffer
*/
void btstack_slip_decoder_init(uint8_t * buffer, uint16_t max_size){
decoder_buffer = buffer;
decoder_max_size = max_size;
btstack_slip_decoder_reset();
}
/**
* @brief Process received byte
* @param data
*/
void btstack_slip_decoder_process(uint8_t input){
switch(decoder_state){
case SLIP_DECODER_UNKNOWN:
if (input != BTSTACK_SLIP_SOF) break;
btstack_slip_decoder_reset();
decoder_state = SLIP_DECODER_X_C0;
break;
case SLIP_DECODER_COMPLETE:
log_error("btstack_slip_decoder_process called in state COMPLETE");
btstack_slip_decoder_reset();
break;
case SLIP_DECODER_X_C0:
switch(input){
case BTSTACK_SLIP_SOF:
break;
case 0xdb:
decoder_state = SLIP_DECODER_X_DB;
break;
default:
btstack_slip_decoder_store_byte(input);
decoder_state = SLIP_DECODER_ACTIVE;
break;
}
break;
case SLIP_DECODER_X_DB:
switch(input){
case 0xdc:
btstack_slip_decoder_store_byte(BTSTACK_SLIP_SOF);
decoder_state = SLIP_DECODER_ACTIVE;
break;
case 0xdd:
btstack_slip_decoder_store_byte(0xdb);
decoder_state = SLIP_DECODER_ACTIVE;
break;
default:
btstack_slip_decoder_reset();
break;
}
break;
case SLIP_DECODER_ACTIVE:
switch(input){
case BTSTACK_SLIP_SOF:
if (decoder_pos){
decoder_state = SLIP_DECODER_COMPLETE;
} else {
btstack_slip_decoder_reset();
}
break;
case 0xdb:
decoder_state = SLIP_DECODER_X_DB;
break;
default:
btstack_slip_decoder_store_byte(input);
break;
}
break;
}
}
/**
* @brief Get size of decoded frame
* @return size of frame. Size = 0 => frame not complete
*/
uint16_t btstack_slip_decoder_frame_size(void){
switch (decoder_state){
case SLIP_DECODER_COMPLETE:
return decoder_pos;
default:
return 0;
}
}
#endif

23
src/btstack_slip.h
View File

@ -72,6 +72,29 @@ int btstack_slip_encoder_has_data(void);
*/
uint8_t btstack_slip_encoder_get_byte(void);
// DECODER
/**
* @brief Initialise SLIP decoder with buffer
* @param buffer to store received data
* @param max_size of buffer
*/
void btstack_slip_decoder_init(uint8_t * buffer, uint16_t max_size);
/**
* @brief Process received byte
* @param input
*/
void btstack_slip_decoder_process(uint8_t input);
/**
* @brief Get size of decoded frame
* @return size of frame. Size = 0 => frame not complete
*/
uint16_t btstack_slip_decoder_frame_size(void);
#if defined __cplusplus
}
#endif