/////////////////////////////////////////////////////////////////////////////////
//
// modbus.h is part of TestModbus-Client.
//
/////////////////////////////////////////////////////////////////////////////////

#ifndef _MODBUS_H_
#define _MODBUS_H_

#include <stdint.h>
#include <stdlib.h>

/*
 * this file will only contain the encoding and decoding functions
 */

struct {
	uint16_t transid;	// transaction id
	uint16_t protid;	// protocol id
	uint16_t length;	// number of bytes followed
	uint8_t uid;		// unit/slave id
	uint8_t fc;			// function code
	uint16_t offset;	// first register to read
	uint16_t number;	// number of registers to read
} typedef modbustcp_rq_header;


struct {
	uint16_t transid;	// transaction id
	uint16_t protid;	// protocol id
	uint16_t length;	// number of bytes followed
	uint8_t uid;		// unit/slave id
	uint8_t fc;			// function code
	uint8_t number;	// number of registers to read
} typedef modbustcp_res_header;

char * modbustcp_pkt_headerrq (char *destbuffer, int bufsize, modbustcp_rq_header *srcmbh);
char * modbustcp_unpkt_headerrq (modbustcp_rq_header *destmbh, char *srcbuffer, int bufsize);

char * modbustcp_pkt_headerres (char *destbuffer, int bufsize, modbustcp_res_header *srcmbh);
char * modbustcp_unpkt_headerres (modbustcp_res_header *destmbh, char *srcbuffer, int bufsize);


#endif