tcoap_helpers.h

/**
 * tcoap_helpers.h
 *
 * Author: Serge Maslyakov, rusoil.9@gmail.com
 * Copyright 2017 Serge Maslyakov. All rights reserved.
 *
 */


#ifndef __TCOAP_HELPERS_H
#define __TCOAP_HELPERS_H


#include <stdint.h>
#include "tcoap.h"


#ifdef __cplusplus
extern "C" {
#endif


typedef enum {

    TCOAP_BLOCK_SZX_VAL_0       = 16,
    TCOAP_BLOCK_SZX_VAL_1       = 32,
    TCOAP_BLOCK_SZX_VAL_2       = 64,
    TCOAP_BLOCK_SZX_VAL_3       = 128,
    TCOAP_BLOCK_SZX_VAL_4       = 256,
    TCOAP_BLOCK_SZX_VAL_5       = 512,
    TCOAP_BLOCK_SZX_VAL_6       = 1024,

    /**
     * Reserved, i.e., MUST NOT be sent and
     * MUST lead to a 4.00 Bad Request response
     * code upon reception in a request.
     */
    TCOAP_BLOCK_SZX_VAL_7       = 0

} tcoap_blockwise_szx;


typedef union tcoap_blockwise_data {

    struct {
        uint32_t num         : 24;
        uint32_t block_szx   : 3;
        uint32_t more        : 1;
    } fld;

    uint8_t arr[4];

} tcoap_blockwise_data;


/**
 * @brief Get block size by SZX value
 *
 * @param szx - a three-bit unsigned integer indicating the size of a block to the power of two.
 *
 */
uint16_t tcoap_decode_szx_to_size(const uint8_t szx);


/**
 * @brief Fill block2 option
 *
 * @param option - pointer on the 'tcoap_option_data' struct
 * @param bw - pointer on the block2 data
 * @param value - buffer for storing encoded value (max length is 3)
 *
 */
void tcoap_fill_block2_opt(tcoap_option_data * const option, const tcoap_blockwise_data * const bw, uint8_t * const value);


/**
 * @brief Extract block2 value from option
 *
 * @param block2 - raw option contains block2
 * @param bw - pointer on the block2 data to store value
 *
 */
void tcoap_extract_block2_from_opt(const tcoap_option_data * const block2, tcoap_blockwise_data * const bw);


/**
 * @brief Find an option by its number
 *
 * @param options - list of options
 * @param opt_num - number of option
 *
 * @return pointer to the found option or NULL if option is absent
 */
const tcoap_option_data * tcoap_find_option_by_number(const tcoap_option_data * options, const uint16_t opt_num);


#ifdef  __cplusplus
}
#endif

#endif /* __TCOAP_HELPERS_H */