AirControlValve/Lib/cobs.h

/*****************************************************************************
 *
 * cobs.h
 *
 * Consistent Overhead Byte Stuffing
 *
 * https://github.com/cmcqueen/cobs-c
 *
 * The COBS encoding does have to increase the packet size to achieve this encoding. However, compared to other byte-stuffing methods,
 * the packet size increase is reasonable and predictable. COBS always adds 1 byte to the message length. Additionally,
 * for longer packets of length n, it may add n/254 (rounded down) additional bytes to the encoded packet size.
 ****************************************************************************/

#ifndef COBS_H_
#define COBS_H_


/*****************************************************************************
 * Includes
 ****************************************************************************/
#include "ac780x.h"


/*****************************************************************************
 * Defines
 ****************************************************************************/

#define COBS_ENCODE_DST_BUF_LEN_MAX(SRC_LEN)            ((SRC_LEN) + (((SRC_LEN) + 253u)/254u))
#define COBS_DECODE_DST_BUF_LEN_MAX(SRC_LEN)            (((SRC_LEN) == 0) ? 0u : ((SRC_LEN) - 1u))


/*****************************************************************************
 * Typedefs
 ****************************************************************************/

typedef enum
{
    COBS_ENCODE_OK                  = 0x00,
    COBS_ENCODE_NULL_POINTER        = 0x01,
    COBS_ENCODE_OUT_BUFFER_OVERFLOW = 0x02
} cobs_encode_status;

typedef struct
{
    size_t              out_len;
    cobs_encode_status  status;
} cobs_encode_result;


typedef enum
{
    COBS_DECODE_OK                  = 0x00,
    COBS_DECODE_NULL_POINTER        = 0x01,
    COBS_DECODE_OUT_BUFFER_OVERFLOW = 0x02,
    COBS_DECODE_ZERO_BYTE_IN_INPUT  = 0x04,
    COBS_DECODE_INPUT_TOO_SHORT     = 0x08
} cobs_decode_status;

typedef struct
{
    size_t              out_len;
    cobs_decode_status  status;
} cobs_decode_result;


/*****************************************************************************
 * Function prototypes
 ****************************************************************************/

#ifdef __cplusplus
extern "C" {
#endif

cobs_encode_result cobs_encode(uint8_t *dst_buf_ptr, size_t dst_buf_len, const uint8_t * src_ptr, size_t src_len);
cobs_decode_result cobs_decode(uint8_t *dst_buf_ptr, size_t dst_buf_len, const uint8_t * src_ptr, size_t src_len);


#ifdef __cplusplus
} /* extern "C" */
#endif


#endif /* COBS_H_ */