/* ZZM.C Part 2 */

#include "zmp.h"
#include "zmodem.h"

#undef DEBUG

#ifdef   AZTEC_C
#include "libc.h"
#else
#include <stdio.h>
#endif

extern long updc32();

/* Receive a binary style header (type and position) */
zrbhdr(hdr)
char *hdr;
{
	static int c, n;
	static unsigned crc;

	if ((c = zdlread()) & ~0377)
		return c;
	Rxtype = c;
	crc = updcrc(c, 0);

	for (n=4; --n >= 0; ++hdr) {
		if ((c = zdlread()) & ~0377)
			return c;
		crc = updcrc(c, crc);
		*hdr = c;
	}
	if ((c = zdlread()) & ~0377)
		return c;
	crc = updcrc(c, crc);
	if ((c = zdlread()) & ~0377)
		return c;
	crc = updcrc(c, crc);
	if (crc & 0xFFFF) {
		zperr("Bad Header CRC",TRUE); 
		return NERROR;
	}
	Zmodem = 1;

#ifdef DEBUG
	printf("\nReceived BINARY header type %d: ",Rxtype);
	for (n = -4; n < 0; n++)
		prhex( *(hdr + n));
	printf("\n");
#endif

	return Rxtype;
}

/* Receive a binary style header (type and position) with 32 bit FCS */
zrb32hdr(hdr)
char *hdr;
{
	static int c, n;
	static long crc;

	if ((c = zdlread()) & ~0377)
		return c;
	Rxtype = c;
	crc = 0xFFFFFFFFL; 
	crc = updc32(c, crc);
#ifdef DEBUGZ
#endif

	for (n=4; --n >= 0; ++hdr) {
		if ((c = zdlread()) & ~0377)
			return c;
		crc = updc32(c, crc);
		*hdr = c;
#ifdef DEBUGZ
#endif
	}
	for (n=4; --n >= 0;) {
		if ((c = zdlread()) & ~0377)
			return c;
		crc = updc32(c, crc);
#ifdef DEBUGZ
#endif
	}
	if (crc != 0xDEBB20E3) {
		zperr("Bad Header CRC",TRUE); 
		return NERROR;
	}
	Zmodem = 1;

#ifdef DEBUG
	printf("\nReceived 32-bit FCS BINARY header type %d: ",Rxtype);
	for (n = -4; n < 0; n++)
		prhex( *(hdr + n));
	printf("\n");
#endif

	return Rxtype;
}


/* Receive a hex style header (type and position) */
zrhhdr(hdr)
char *hdr;
{
	static int c;
	static unsigned crc;
	static int n;

	if ((c = zgethex()) < 0)
		return c;
	Rxtype = c;
	crc = updcrc(c, 0);

	for (n=4; --n >= 0; ++hdr) {
		if ((c = zgethex()) < 0)
			return c;
		crc = updcrc(c, crc);
		*hdr = c;
	}
	if ((c = zgethex()) < 0)
		return c;
	crc = updcrc(c, crc);
	if ((c = zgethex()) < 0)
		return c;
	crc = updcrc(c, crc);
	if (crc & 0xFFFF) {
		zperr("Bad Header CRC",TRUE); 
		return NERROR;
	}
	if (readline(INTRATIME) == '\r')	/* Throw away possible cr/lf */
		readline(INTRATIME);
	Zmodem = 1; 

#ifdef DEBUG
	printf("\nReceived HEX header type %d: ",Rxtype);
	for (n = -4; n < 0; n++)
		prhex( *(hdr + n));
	printf("\n");
#endif

	return Rxtype;
}

/* Send a byte as two hex digits */
zputhex(c)
int c;
{
	static char	digits[]	= "0123456789abcdef";

   xmchout(digits[(c&0xF0)>>4]);
   xmchout(digits[(c)&0xF]);
}

/*
 * Send character c with ZMODEM escape sequence encoding.
 *  Escape XON, XOFF. Escape CR following @ (Telenet net escape)
 */
zsendline(c)
int c;
{
	static lastsent;

	switch (c &= 0377) {
	case ZDLE:
		xmchout(ZDLE);
		xmchout (lastsent = (c ^= 0100));
		break;
	case 015:
	case 0215:
		if (!Zctlesc && (lastsent & 0177) != '@')
			goto sendit;
		/* **** FALL THRU TO **** */
	case 020:
	case 021:
	case 023:
	case 0220:
	case 0221:
	case 0223:
		xmchout(ZDLE);
		c ^= 0100;
sendit:
		xmchout(lastsent = c);
		break;
	default:
		if (Zctlesc && ! (c & 0140)) {
			xmchout(ZDLE);
			c ^= 0100;
		}
		xmchout(lastsent = c);
	}
}

/* Decode two lower case hex digits into an 8 bit byte value */
zgethex()
{
	int c;

	c = zgeth1();
	return c;
}
zgeth1()
{
	static int c, n;

	if ((c = noxrd7()) < 0)
		return c;
	n = c - '0';
	if (n > 9)
		n -= ('a' - ':');
	if (n & ~0xF)
		return NERROR;
	if ((c = noxrd7()) < 0)
		return c;
	c -= '0';
	if (c > 9)
		c -= ('a' - ':');
	if (c & ~0xF)
		return NERROR;
	c += (n<<4);
	return c;
}

/*
 * Read a byte, checking for ZMODEM escape encoding
 *  including CAN*5 which represents a quick abort
 */

zdlread()
{
	static int c;

again:
	switch (c = readline(Rxtimeout)) {
	case ZDLE:
		break;
	case 023:
	case 0223:
	case 021:
	case 0221:
		goto again;
	default:
		if (Zctlesc && !(c & 0140)) {
			goto again;
		}
		return c;
	}
again2:
	if ((c = readline(Rxtimeout)) < 0)
		return c;
	if (c == CAN && (c = readline(Rxtimeout)) < 0)
		return c;
	if (c == CAN && (c = readline(Rxtimeout)) < 0)
		return c;
	if (c == CAN && (c = readline(Rxtimeout)) < 0)
		return c;
	switch (c) {
	case CAN:
		return GOTCAN;
	case ZCRCE:
	case ZCRCG:
	case ZCRCQ:
	case ZCRCW:
		return (c | GOTOR);
	case ZRUB0:
		return 0177;
	case ZRUB1:
		return 0377;
	case 023:
	case 0223:
	case 021:
	case 0221:
		goto again2;
	default:
		if (Zctlesc && ! (c & 0140)) {
			goto again2;
		}
		if ((c & 0140) ==  0100)
			return (c ^ 0100);
		break;
	}
   sprintf(Buf,"Bad escape %x", c);
	zperr(Buf,TRUE);
	return NERROR;
}

/*
 * Read a character from the modem line with timeout.
 *  Eat parity, XON and XOFF characters.
 */
noxrd7()
{
	static int c;

	for (;;) {
		if ((c = readline(Rxtimeout)) < 0)
			return c;
		switch (c &= 0177) {
		case XON:
		case XOFF:
			continue;
		default:
			if (Zctlesc && !(c & 0140))
				continue;
		case '\r':
		case '\n':
		case ZDLE:
			return c;
		}
	}
}

/* Store long integer pos in Txhdr */
stohdr(pos)
long pos;
{
	Txhdr[ZP0] = pos;
	Txhdr[ZP1] = (pos>>8);
	Txhdr[ZP2] = (pos>>16);
	Txhdr[ZP3] = (pos>>24);
}

/* Recover a long integer from a header */
long
rclhdr(hdr)
char *hdr;
{
	static long l;

	l = (unsigned)(hdr[ZP3] & 0377);
	l = (l << 8) | (unsigned)(hdr[ZP2] & 0377);
	l = (l << 8) | (unsigned)(hdr[ZP1] & 0377);
	l = (l << 8) | (unsigned)(hdr[ZP0] & 0377);
#ifdef DEBUG
   lreport(FBLOCKS,l);
#endif
	return l;
}

/***************************** End of hzm2.c *********************************/