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cobsr.h
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cobsr.h
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/*****************************************************************************
*
* cobsr.h
*
* Consistent Overhead Byte Stuffing--Reduced (COBS/R)
*
****************************************************************************/
#ifndef COBSR_H_
#define COBSR_H_
/*****************************************************************************
* Includes
****************************************************************************/
#include <stdint.h>
#include <stdlib.h>
/*****************************************************************************
* Defines
****************************************************************************/
#define COBSR_ENCODE_DST_BUF_LEN_MAX(SRC_LEN) (((SRC_LEN) == 0u) ? 1u : ((SRC_LEN) + (((SRC_LEN) + 253u) / 254u)))
#define COBSR_DECODE_DST_BUF_LEN_MAX(SRC_LEN) (SRC_LEN)
/*
* For in-place encoding, the source data must be offset in the buffer by
* the following amount (or more).
*/
#define COBSR_ENCODE_SRC_OFFSET(SRC_LEN) (((SRC_LEN) + 253u)/254u)
/*****************************************************************************
* Typedefs
****************************************************************************/
typedef enum
{
COBSR_ENCODE_OK = 0x00,
COBSR_ENCODE_NULL_POINTER = 0x01,
COBSR_ENCODE_OUT_BUFFER_OVERFLOW = 0x02
} cobsr_encode_status;
typedef struct
{
size_t out_len;
cobsr_encode_status status;
} cobsr_encode_result;
typedef enum
{
COBSR_DECODE_OK = 0x00,
COBSR_DECODE_NULL_POINTER = 0x01,
COBSR_DECODE_OUT_BUFFER_OVERFLOW = 0x02,
COBSR_DECODE_ZERO_BYTE_IN_INPUT = 0x04,
} cobsr_decode_status;
typedef struct
{
size_t out_len;
cobsr_decode_status status;
} cobsr_decode_result;
/*****************************************************************************
* Function prototypes
****************************************************************************/
#ifdef __cplusplus
extern "C" {
#endif
/* COBS/R-encode a string of input bytes, which may save one byte of output.
*
* dst_buf_ptr: The buffer into which the result will be written
* dst_buf_len: Length of the buffer into which the result will be written
* src_ptr: The byte string to be encoded
* src_len Length of the byte string to be encoded
*
* returns: A struct containing the success status of the encoding
* operation and the length of the result (that was written to
* dst_buf_ptr)
*/
cobsr_encode_result cobsr_encode(void * dst_buf_ptr, size_t dst_buf_len,
const void * src_ptr, size_t src_len);
/* Decode a COBS/R byte string.
*
* dst_buf_ptr: The buffer into which the result will be written
* dst_buf_len: Length of the buffer into which the result will be written
* src_ptr: The byte string to be decoded
* src_len Length of the byte string to be decoded
*
* returns: A struct containing the success status of the decoding
* operation and the length of the result (that was written to
* dst_buf_ptr)
*/
cobsr_decode_result cobsr_decode(void * dst_buf_ptr, size_t dst_buf_len,
const void * src_ptr, size_t src_len);
#ifdef __cplusplus
} /* extern "C" */
#endif
#endif /* COBSR_H_ */