msgpkt.c

为了满足每个项目终端的需求

/***************************************************************************
*
*		FileName:       msgpkt.c
*		Revision:       2008/08/04
*		Author:			Du Biao
****************************************************************************
* DESCRIPTION:
    process pkt send,read and check
*
* COPYRIGHT:
	(C) HEBEI FAR-EAST HARRIS COMMUNICATIONS COMPANY LTD.

* HISTORY:
	08/08/04:
		Initial verison by Du Biao
*
*/


#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#include "../inc/version.h"
#include "../inc/gendef.h"
#include "../inc/channel.h"
#include "../inc/msgpkt.h"

//#undef MSGPKT_DEBUG
#define MSGPKT_DEBUG

#ifdef MSGPKT_DEBUG
	#define MSGPKT_DPRINTF( x... )	printf("msgpkt_pthread: \t" ##x)
#else
	#define MAGPKT_DPRINTF( x... )
#endif




/************************************************************************
* PktCalcCRC
*************************************************************************
FUNCTION: get the date CRC
INPUTS:   pData: data which will do CRC; iDatalength:length of pData
OUTPUTS:  none
RETURN:   0 is OK, otherwise error
*
*/

unsigned char PktCalcCRC(unsigned char *pData,int iDataLength)
{
	int i;
	int iDemoLength;
	unsigned char CRC = 0;

	iDemoLength = iDataLength*8;

	//debug
		for( i = 0; i < iDemoLength; i++)
		{
			/*if bit i in telegram XOR bit to shift out*/
			if(((pData[i >> 3]>>(i & 7))^CRC) & 1)
			{
				CRC=(CRC >> 1)^0xCF;
			}
			else
			{
				CRC >>= 1;
			}
		}
		
		return CRC;
/*
	}
	else
	{
		MSGPKT_DPRINTF("CRC ERROR over %d\n", (iDemoLength >> 3));
	}
*/
	
}




/************************************************************************
* Sendpkt
*************************************************************************
FUNCTION: build and sendpkt to channel
INPUTS:   dev: device handle,event: msg type,
		  info: buffer to send infolen:length of info
OUTPUTS:  none
RETURN:   -1 is error, otherwise ok
*
*/
int SendPkt(int dev,U8 event,FILE_DATA* info,U32 infolen)
{
	PKT outpkt;
//char aaa[100];

	if(infolen > MAX_FILE_DATA_LEN+7)
	{
		MSGPKT_DPRINTF(" pkt send is too large\n");
		return -1;
	}

	memset((U8*)&outpkt,'\0',sizeof(PKT));
	outpkt.Start = START_BYTE;
	outpkt.MsgType = event;

	if((info != NULL) && (infolen != 0))
	{
		//memcpy(outpkt.Msg, info, infolen);
		outpkt.Msg.Index = info->Index;
		outpkt.Msg.Sum = info->Sum;
		outpkt.Msg.BCC = info->BCC;
		outpkt.Msg.DataLen = info->DataLen;
		memset(outpkt.Msg.Data,'0',MAX_FILE_DATA_LEN);
		memcpy(outpkt.Msg.Data, info->Data, outpkt.Msg.DataLen);
	}
#if 0
	MSGPKT_DPRINTF("111hello_tempbuffer.Index is %d\n",outpkt.Msg.Index);
	MSGPKT_DPRINTF("111hello_tempbuffer.Sum is %d\n",outpkt.Msg.Sum);
	MSGPKT_DPRINTF("111hello_tempbuffer.DataLen is %d\n",outpkt.Msg.DataLen);
	MSGPKT_DPRINTF("111hello_tempbuffer.Data is %s\n",outpkt.Msg.Data);
	MSGPKT_DPRINTF("111hello_tempbuffer.BCC is %d\n",outpkt.Msg.BCC);
	//MSGPKT_DPRINTF("CHN_Send BUFF is %s\n", &outpkt);
#endif

	return CHN_Send(dev,(U8 *)&outpkt, MAX_FILE_DATA_LEN+9);

}




/************************************************************************
*readpkt
*************************************************************************
FUNCTION: build and read pkt from channel
INPUTS:   dev: device handle, pkt: msg to read,
		  infolen: length of msg to send
OUTPUTS:  none
RETURN:    -1 is error, otherwise ok
*
*/

int ReadPkt(int dev,PKT* pkt,U32 infolen)
{
	return  CHN_Recv(dev, (U8*) pkt, infolen);
}




/************************************************************************
* CheckPkt
*************************************************************************
FUNCTION: check the pkt received or get ready for send
INPUTS:   pkt: the msg to check
OUTPUTS:  none
RETURN:    -1 is error, otherwise ok
*
*/
U8 CheckPkt(PKT *pkt)
{
	U8 bcc;
	int info_len;
	//info_len = ntohs(pkt->Msg.DataLen);
	info_len = pkt->Msg.DataLen;
	//printf("check pkt before crc %d,%d\n",pkt->Msg.DataLen,sizeof(pkt->Msg.Data));
	
	bcc = PktCalcCRC(pkt->Msg.Data,info_len);
	//printf("check pkt after crc\n");
	if(bcc == pkt->Msg.BCC)
	{
		return 0;
	}
	else
	{
		return -1;
	}
}