Tag-Value-Length Persistent Storage (TLV) API

btstack_tlv.h : Inteface for BTstack's Tag Value Length Persistent Storage implementations used to store pairing/bonding data.

typedef struct {

    /**
     * Get Value for Tag
     * @param context
     * @param tag
     * @param buffer
     * @param buffer_size
     * @returns size of value
     */
    int (*get_tag)(void * context, uint32_t tag, uint8_t * buffer, uint32_t buffer_size);

    /**
     * Store Tag 
     * @param context
     * @param tag
     * @param data
     * @param data_size
     * @returns 0 on success
     */
    int (*store_tag)(void * context, uint32_t tag, const uint8_t * data, uint32_t data_size);

    /**
     * Delete Tag
     *  @note it is not expected that delete operation fails, please use at least log_error in case of errors
     * @param context
     * @param tag
     */
    void (*delete_tag)(void * context,  uint32_t tag);

} btstack_tlv_t;

/** 
 * @brief Make TLV implementation available to BTstack components via Singleton
 * @note Usually called by port after BD_ADDR was retrieved from Bluetooth Controller
 * @param tlv_impl
 * @param tlv_context
 */
void btstack_tlv_set_instance(const btstack_tlv_t * tlv_impl, void * tlv_context);

/**
 * @brief Get current TLV implementation. Used for bonding information, but can be used by application, too.
 * @param tlv_impl
 * @param tlv_context
 */
void btstack_tlv_get_instance(const btstack_tlv_t ** tlv_impl, void ** tlv_context);