sensor_db.h

#ifndef _SENSOR_DB_H_
#define _SENSOR_DB_H_

#include <stdio.h>
#include <stdlib.h>
#include <sqlite3.h>
#include "config.h"
#include "sbuffer.h"

// stringify preprocessor directives using 2-level preprocessor magic
// this avoids using directives like -DDB_NAME=\"some_db_name\"
#define REAL_TO_STRING(s) #s
#define TO_STRING(s) REAL_TO_STRING(s)    //force macro-expansion on s before stringify s

#ifndef DB_NAME
    #define DB_NAME Sensor.db
#endif

#ifndef TABLE_NAME
    #define TABLE_NAME SensorData
#endif

#define DBCONN sqlite3 

typedef int (*callback_t)(void *, int, char **, char **);

/*
 * Reads continiously all data from the shared buffer data structure and stores this into the database
 * When *buffer becomes NULL the method finishes. This method will NOT automatically disconnect from the db
 */
void storagemgr_parse_sensor_data(DBCONN * conn, sbuffer_t ** buffer);

/*
 * Make a connection to the database server
 * Create (open) a database with name DB_NAME having 1 table named TABLE_NAME  
 * If the table existed, clear up the existing data if clear_up_flag is set to 1
 * Return the connection for success, NULL if an error occurs
 */
DBCONN * init_connection(char clear_up_flag);

/*
 * Disconnect from the database server, and free all used memory
 */
void disconnect(DBCONN * conn);

/*
 * Write an INSERT query to insert a single sensor measurement
 * Return zero for success, and non-zero if an error occurs
 */
int insert_sensor(DBCONN * conn, sensor_id_t id, sensor_value_t value, sensor_ts_t ts);

/*
  * Write a SELECT query to select all sensor measurements in the table 
  * The callback function is applied to every row in the result
  * Return zero for success, and non-zero if an error occurs
  */
int find_sensor_all(DBCONN * conn, callback_t f);

/*
 * Write a SELECT query to return all sensor measurements having a temperature of 'value'
 * The callback function is applied to every row in the result
 * Return zero for success, and non-zero if an error occurs
 */
int find_sensor_by_value(DBCONN * conn, sensor_value_t value, callback_t f);

/*
 * Write a SELECT query to return all sensor measurements of which the temperature exceeds 'value'
 * The callback function is applied to every row in the result
 * Return zero for success, and non-zero if an error occurs
 */
int find_sensor_exceed_value(DBCONN * conn, sensor_value_t value, callback_t f);

/*
 * Write a SELECT query to return all sensor measurements having a timestamp 'ts'
 * The callback function is applied to every row in the result
 * Return zero for success, and non-zero if an error occurs
 */
int find_sensor_by_timestamp(DBCONN * conn, sensor_ts_t ts, callback_t f);

/*
 * Write a SELECT query to return all sensor measurements recorded after timestamp 'ts'
 * The callback function is applied to every row in the result
 * return zero for success, and non-zero if an error occurs
 */
int find_sensor_after_timestamp(DBCONN * conn, sensor_ts_t ts, callback_t f);

/**
 * This method shares variables from threads space to carry out more functionality,
 * like having access to IPC mutex/rwlock and updating the return value of the thread
 **/
void storagemgr_init(storagemgr_init_arg_t * arg);

#endif /* _SENSOR_DB_H_ */