#ifndef _TIMESTAMP_H_#define _TIMESTAMP_H_#include <sos_types.h>#include <message_types.h>//! use 27 bytes on mica2#define TIMESTAMP_DEFAULT_SIZE   4#ifndef _MODULE_/** * @brief register timestamping service * @param pid module ID * @param n   time stamp buffer size * @return SOS_OK for success, errno for error * * Module uses this to register itself with timestamping service * When there is incoming and outgoing messages, the timestamp will be  * recorded along with msg->data field. * Module uses ker_timestamp_query to get the timestamp * One can always use TIMESTAMP_DEFAULT_SIZE when not sure */int8_t ker_timestamp_register(sos_pid_t pid, uint8_t n);/** * @brief deregister timestamp service */int8_t ker_timestamp_deregister(sos_pid_t pid);/** * @brief query the time stamp of a message * @param pid module ID * @param data msg->data field * @return timestamp for success, 0 for fail * * Each timestamp is associated with msg->data for both  * incoming and outgoing messages *  */uint32_t ker_timestamp_query(sos_pid_t pid, void *data);/** * @brief telling timestamp service that a message is in * Used by radio driver */void timestamp_incoming(Message *msg_in, uint32_t t);/** * @brief telling timestamp service that a message is sent * Used by radio driver */void timestamp_outgoing(Message *msg_out, uint32_t t);#endif /* ifndef _MODULE_ */#endif