txmodem.c

标准的c代码

/* 
====================================================================================
*   this code needs standard functions memcpy() and memset()
*  and input/output functions port_inbyte() and port_outbyte().
*
*   the prototypes of the input/output functions are:
*   INT32S port_inbyte(INT16U timeout); // msec timeout
*   void port_outbyte(INT32S c);
=====================================================================================
 */


#include "modem.h"
#include "serial.h"
#include "brd.h"


#include "string.h"
#define port_outbyte urtPutData
#define port_inbyte	 getByteInTime	

#define SOH 0x01
#define EOT 0x04
#define ACK 0x06
#define NAK 0x15
#define CAN 0x18
#define EOF 0x1A 
#define STX 0x02
#define BS  0x08
/*add by hojin 5/12/2008*/
#define CTRLZ 0x1A

#if 0
void port_outbyte(INT8U trychar)
{
	INT8U buf[2];
	buf[0] = trychar;
	lowLevel_write(buf,1);
}

INT8U port_inbyte(INT32U time_out)
{
	INT8U ch;
	INT32S i;
	last_error = 0;

	if(lowLevel_read(&ch,1) == 1)
		return ch;

	last_error = 1;
	return ch;
}
#endif

/****************Portting End*******************/
static INT32S check(INT32S crc,  INT8U *buf, INT32S sz)
{
	if (crc) 
	{
		INT16U crc = crc16_ccitt(buf, sz);
		INT16U tcrc = (buf[sz]<<8)+buf[sz+1];
		if (crc == tcrc)
			return 1;
	}
	else 
	{
		INT32S i;
		INT8U cks = 0;
		for (i = 0; i < sz; ++i) 
		{
			cks += buf[i];
		}
		if (cks == buf[sz])
		return 1;
	}

	return 0;
}

static void flushinput(void)
{
	while (port_inbyte(DLY_1S) >= 0);
		
}

INT32S xmodemReceive(INT8U *dest, INT32S destsz)
{
	INT8U xbuff[1030]; /* 1024 for XModem 1k + 3 head chars + 2 crc + nul */
	INT8U *p;
	INT32S bufsz, crc = 0;
	INT8U trychar = 'C';
	INT8U packetno = 1;
	INT32S i, c, len = 0;
	INT32S retry, retrans = MAXRETRANS, noDataRetry = MAXRETRANS ;

	for(;;) 
	{
		for( retry = 0; retry < 50; ++retry) 
		{
			if (trychar) 
				port_outbyte(trychar);
			c = port_inbyte((DLY_1S));
			if (c >= 0) 
			{
			noDataRetry = 15;    /*  短线15秒之内能恢复连接不会产生错误。*/
				switch (c) 
				{
					case SOH:
						bufsz = 128;
						goto start_recv;
					case STX:
						bufsz = 1024;
						goto start_recv;
					case EOT:
						flushinput();
						port_outbyte(ACK);
						return len; /* normal end */
					case ESC_KEY:
						c = port_inbyte(DLY_1S);
						if (c == ESC_KEY) {
						urtPrintf("\nCanceled by user in modem receive!\n");
						return MODEM_USER_CAN; /* sync error */
						}
						break;
					case CAN:
						c = port_inbyte(DLY_1S);

						if (c == CAN) 
						{
							flushinput();
							port_outbyte(ACK);
							return MODEM_CANCLE; /* canceled by remote */
						}
						break;
					default:
						goto reject;   /*add by hojin */
						break;
				}
			}
			else
			{	
				if(trychar == 0)
				{ 
					if (--noDataRetry <= 0) 
					{
					flushinput();
					port_outbyte(CAN);
					port_outbyte(CAN);
					port_outbyte(CAN);
					return MODEM_MID_NO_LINK; /* too many nodata retry error */
					}
				goto reject;  /*hojin added */
				}
			}
		}
		if (trychar == 'C') 
		{ 
			trychar = NAK; 
			continue; 
		}
		flushinput();
		port_outbyte(CAN);
		port_outbyte(CAN);
		port_outbyte(CAN);
		return MODEM_START_NO_LINK; /* sync error */

	start_recv:
		if (trychar == 'C') crc = 1;
		trychar = 0;
		p = xbuff;
		*p++ = c;
		for (i = 0;  i < (bufsz+(crc?1:0)+3); ++i) 
		{
			c = port_inbyte(DLY_1S);

			if (c < 0) 
				goto reject;
			*p++ = (c & 0xff);
		}

		if (xbuff[1] == (INT8U)(~xbuff[2]) && 
			(xbuff[1] == packetno || xbuff[1] == (INT8U)packetno-1) &&
			check(crc, &xbuff[3], bufsz)) 
		{
			if (xbuff[1] == packetno)	
			{
				INT32S count = destsz - len;
				if (count > bufsz) 
					count = bufsz;
				if (count > 0) 
				{
					memcpy (&dest[len], &xbuff[3], count);
					len += count;
				}
				++packetno;
				retrans = MAXRETRANS+1;
			}
			if (--retrans <= 0) 
			{
				flushinput();
				port_outbyte(CAN);
				port_outbyte(CAN);
				port_outbyte(CAN);
				return MODEM_PACKAGE_ERR; /* too many packet error retry error */
			}
			port_outbyte(ACK);
			continue;
		}
	reject:
		flushinput();
		port_outbyte(NAK);
	}
}

INT32S xmodemTransmit(const INT8U *src, INT32S srcsz)
{
	INT8U xbuff[1030]; /* 1024 for XModem 1k + 3 head chars + 2 crc + nul */
	INT32S bufsz, crc = -1;
	INT8U packetno = 1;
	INT32S i, c, len = 0;
	INT32S retry;

	for(;;) {
		for( retry = 0; retry < 100; ++retry) 
		{
			c = port_inbyte((DLY_1S)<<1);
			if (c >= 0) 
			{
				switch ((c & 0xff)) 
				{
					case 'C':
						crc = 1;
						goto start_trans;
					case NAK:
						crc = 0;
						goto start_trans;
					case CAN:
						c = port_inbyte(DLY_1S);
						if (c == CAN) 
						{
							port_outbyte(ACK);
							flushinput();
							return MODEM_CANCLE; /* canceled by remote */
						}
						break;
					default:
						break;
				}
			}
				
		}
		port_outbyte(CAN);
		port_outbyte(CAN);
		port_outbyte(CAN);
		flushinput();
		return MODEM_START_NO_LINK; /* no sync */

		for(;;) 
		{
		start_trans:
			xbuff[0] = SOH; bufsz = 128;
			xbuff[1] = packetno;
			xbuff[2] = ~packetno;
			c = srcsz - len;
			if (c > bufsz) c = bufsz;
			if (c >= 0) 
			{
				memset (&xbuff[3], 0, bufsz);
				if (c == 0) 
				{
					xbuff[3] = CTRLZ;
				}
				else 
				{
					memcpy (&xbuff[3], &src[len], c);
					if (c < bufsz) xbuff[3+c] = CTRLZ;
				}
				if (crc) 
				{
					INT16U ccrc = crc16_ccitt(&xbuff[3], bufsz);
					xbuff[bufsz+3] = (ccrc>>8) & 0xFF;
					xbuff[bufsz+4] = ccrc & 0xFF;
				}
				else 
				{
					INT8U ccks = 0;
					for (i = 3; i < bufsz+3; ++i) 
					{
						ccks += xbuff[i];
					}
					xbuff[bufsz+3] = ccks;
				}
				for (retry = 0; retry < MAXRETRANS; ++retry) 
				{
					for (i = 0; i < bufsz+4+(crc?1:0); ++i) 
					{
						port_outbyte(xbuff[i]);
					}
					c = port_inbyte(DLY_1S);
					if (c >= 0 ) 
					{
						switch (c) 
						{
							case ACK:
								++packetno;
								len += bufsz;
								goto start_trans;
							case CAN:
								c = port_inbyte(DLY_1S);
								if ( c == CAN) 
								{
									port_outbyte(ACK);
									flushinput();
									return MODEM_CANCLE; /* canceled by remote */
								}
								break;
							case NAK:
							default:
								break;
						}
					}
				}
				port_outbyte(CAN);
				port_outbyte(CAN);
				port_outbyte(CAN);
				flushinput();
				return MODEM_MID_NO_LINK; /* xmit error */
			}
			else 
			{
				for (retry = 0; retry < 10; ++retry) 
				{
					port_outbyte(EOT);
					c = port_inbyte((DLY_1S)<<1);
					if (c == ACK) break;
				}
				flushinput();
				return (c == ACK) ? len : MODEM_OTHER_ERR;
			}
		}
	}
}