/****************************************************************************
*	Language 	:	Turbo C 2.0
*	Logfile		:	rbsb.c	
*	Project		:	Comms library.
*	Date 		:	25 Jan 90		
*	Revision 	:	1.1		GT	PC version.	
*	25 Oct 92	:	1.2		GT	KA9Q mods.	
*	30 Jan 93	:	1.3		GT	Fix KA9Q background operation.
*	20 Feb 93	:	1.4		GT	Buffer sends locally.
*	20 Feb 93	:	1.5		GT	Fix return value in send_zbuf ().
*	21 Feb 93	:	1.6		GT	Allocate send buffer from heap.	
*	08 May 93	:	1.7		GT	Fix warnings.							
*	24 Jan 94	:	1.8		GT	_flush -> _rbsb_flush.				
*****************************************************************************
*	Purpose		:	Terminal mode and CRC code.						
*****************************************************************************
*				:	This module is based on the equivalent module in the
*				:	31 Aug 87 version of rz/sz.						
*	$Id: rbsb.c 1.7 94/01/26 13:54:57 ROOT_DOS Exp $
****************************************************************************/

/*
 *
 * -rev 04-16-87
 *  This file contains Unix specific code for setting terminal modes,
 *  very little is specific to ZMODEM or YMODEM per se (that code is in
 *  sz.c and rz.c).  The CRC-16 routines used by XMODEM, YMODEM, and ZMODEM
 *  are also in this file, a fast table driven macro version
 *
 *   This file is #included so the main file can set parameters such as HOWMANY.
 *   See the main files (rz.c/sz.c) for compile instructions.
 */

#include	<stdio.h>
#include	<string.h>
#include	"rbsb.h"
#include	"session.h"
#include	"socket.h"
#include	"usock.h"
#include	"mbuf.h"
#include	"proc.h"
#include	"global.h"

static int send_zbuf (void);

#define	SENDSIZE	(BUFSIZ * 4)

int _z_socket;						/* socket								*/
#if	0
static unsigned char sbuf[SENDSIZE];	/* send buffer						*/
#endif
static unsigned char *sbuf = 0;		/* -> send buffer						*/
static size_t buflen = 0;			/* send buffer size						*/
static unsigned char *bufptr;		/* -> send buffer					*/


/****************************************************************************
*	sndbrk																	*
*	Send break to the modem.												*
****************************************************************************/

void _sendbrk (void)
	{
	/* does nothing */
	}	/* void _sendbrk (void) */


/****************************************************************************
*	_rdchk																	*
*	Returns nz if something to read from remote.							*
****************************************************************************/

int _rdchk (void)
	{
	int rc;

	rc = socklen (_z_socket, 0);
	if (rc < 0)
		rc = 0;

	if (rc == 0)
		pwait (0);					/* let others run					*/

#if	0		
	usflush (_z_socket);
#endif
	return (rc);
	}	/* int _rdchk (void) */

/****************************************************************************
*	_send																	*
*	Send some data to the remote.											*
****************************************************************************/

int _send (unsigned char *buf, int len)
	{
#if	0
	int rc;								/* result code						*/
	int count;							/* byte counter						*/
	int oldmode;			 			/* old socket mode					*/
	int oldflush;			 			/* old flush character				*/
#endif

	if (sbuf == 0)
		{
		sbuf = mallocw (SENDSIZE);
		bufptr = sbuf;
		buflen = 0;
		}
		
	if (len + buflen > SENDSIZE)
		{
		if (send_zbuf () < 0)
			return (0);

		}

	(void) memcpy (bufptr, buf, len);
	bufptr += len;
	buflen += len;
	return (len);
	
#if	0
	count = 0;
	oldmode = sockmode (_z_socket, SOCK_BINARY);
	oldflush = setflush (_z_socket, -1);
	while (len > 0)
		{
		rc = send (_z_socket, buf, len, 0);
		if (rc < 0)
			break;

		len -= rc;
		buf += rc;
		count += rc;
		if (count != len)
			pwait (0);
			
		}

#if	0
	if (rc >= 0)		
		usflush (_z_socket);
#endif
	
	(void) setflush (_z_socket, oldflush);
	(void) sockmode (_z_socket, oldmode);
	return (count);
#endif
	}	/* int _send (unsigned char *buf, int len) */


/*---------------------------------------------------------------------------
*	_rbsb_flush	- Flush output
*--------------------------------------------------------------------------*/

void _rbsb_flush(void)
{
	if (send_zbuf () > 0)
		usflush (_z_socket);
		
}

	
/****************************************************************************
*	send_zbuf																*
*	Sends the send buffer to the remote.									*
****************************************************************************/

static int send_zbuf (void)
	{
	int rc;								/* return value						*/
#if	0
	int count;							/* byte counter						*/
#endif
	int oldmode;			 			/* old socket mode					*/
	int oldflush;			 			/* old flush character				*/
	struct mbuf *bp;					/* -> mbuf							*/

	if (sbuf == 0)
		return (0);
		
	oldmode = sockmode (_z_socket, SOCK_BINARY);
	oldflush = setflush (_z_socket, -1);
	bp = ambufw (SENDSIZE);
	bp->cnt = buflen;
	(void) memcpy (bp->data, sbuf, buflen);
#if	0
	_vfile ("Calling send_mbuf (), count = %d, sbuf = %p\n", bp->cnt, sbuf);
#endif
	rc = send_mbuf (_z_socket, bp, 0, NULLCHAR, 0);
#if	0
	_vfile ("Back from send_mbuf (), rc = %d\n", rc);
#endif
	if (rc < 0)
		rc = 0;
	else
		{
		bufptr = sbuf;
		buflen = 0;
		}

	(void) setflush (_z_socket, oldflush);
	(void) sockmode (_z_socket, oldmode);
	return (rc);
	}	/* static int send_zbuf (void) */
	

/****************************************************************************
*	_receive																*
*	Receive some data from the remote.										*
****************************************************************************/

int _receive (unsigned char *buf, int len)
	{
	int rc;
	int oldmode;			 			/* old socket mode					*/
	int oldflush;			 			/* old flush character				*/
#if	0
	static char rcv_buf[1024];			/* receive buffer					*/
	static char *p;						/* -> receive buffer				*/
	static unsigned count = 0;			/* number of bytes in receive buf	*/
	struct mbuf *bp;					/* -> mbuf							*/
#endif

	oldmode = sockmode (_z_socket, SOCK_BINARY);
	oldflush = setflush (_z_socket, -1);
	rc = recv (_z_socket, (char *) buf, len, 0);
	(void) setflush (_z_socket, oldflush);
	(void) sockmode (_z_socket, oldmode);
	if (rc < 0)
		rc = 0;

#if	0
	/* Do we have any data? */

	if (count == 0)
		{
		oldmode = sockmode (_z_socket, SOCK_BINARY);
		oldflush = setflush (_z_socket, -1);
		rc = recv_mbuf (_z_socket, &bp, 0, NULLCHAR, 0);
		if (rc == -1)
			count = -1;

		(void) setflush (_z_socket, oldflush);
		(void) sockmode (_z_socket, oldmode);
		if (rc <= 0)
			{
			count = 0;
			return (0);
			}

		count = dqdata (bp, rcv_buf, sizeof (rcv_buf));		
		p = rcv_buf;
		}

	if (count >= len)
		{
		(void) memcpy (buf, p, len);
		count -= len;
		p += len;
		return (len);
		}

	/* Can't give all that was asked for. */

	(void) memcpy (buf, p, count);
	rc = count;
	count = 0;
#endif

	return (rc);
	}	/* int _receive (unsigned char *buf, int len) */


/* _crctab calculated by Mark G. Mendel, Network Systems Corporation */

unsigned short _crctab[256] =
	{
    0x0000,  0x1021,  0x2042,  0x3063,  0x4084,  0x50a5,  0x60c6,  0x70e7,
    0x8108,  0x9129,  0xa14a,  0xb16b,  0xc18c,  0xd1ad,  0xe1ce,  0xf1ef,
    0x1231,  0x0210,  0x3273,  0x2252,  0x52b5,  0x4294,  0x72f7,  0x62d6,
    0x9339,  0x8318,  0xb37b,  0xa35a,  0xd3bd,  0xc39c,  0xf3ff,  0xe3de,
    0x2462,  0x3443,  0x0420,  0x1401,  0x64e6,  0x74c7,  0x44a4,  0x5485,
    0xa56a,  0xb54b,  0x8528,  0x9509,  0xe5ee,  0xf5cf,  0xc5ac,  0xd58d,
    0x3653,  0x2672,  0x1611,  0x0630,  0x76d7,  0x66f6,  0x5695,  0x46b4,
    0xb75b,  0xa77a,  0x9719,  0x8738,  0xf7df,  0xe7fe,  0xd79d,  0xc7bc,
    0x48c4,  0x58e5,  0x6886,  0x78a7,  0x0840,  0x1861,  0x2802,  0x3823,
    0xc9cc,  0xd9ed,  0xe98e,  0xf9af,  0x8948,  0x9969,  0xa90a,  0xb92b,
    0x5af5,  0x4ad4,  0x7ab7,  0x6a96,  0x1a71,  0x0a50,  0x3a33,  0x2a12,
    0xdbfd,  0xcbdc,  0xfbbf,  0xeb9e,  0x9b79,  0x8b58,  0xbb3b,  0xab1a,
    0x6ca6,  0x7c87,  0x4ce4,  0x5cc5,  0x2c22,  0x3c03,  0x0c60,  0x1c41,
    0xedae,  0xfd8f,  0xcdec,  0xddcd,  0xad2a,  0xbd0b,  0x8d68,  0x9d49,
    0x7e97,  0x6eb6,  0x5ed5,  0x4ef4,  0x3e13,  0x2e32,  0x1e51,  0x0e70,
    0xff9f,  0xefbe,  0xdfdd,  0xcffc,  0xbf1b,  0xaf3a,  0x9f59,  0x8f78,
    0x9188,  0x81a9,  0xb1ca,  0xa1eb,  0xd10c,  0xc12d,  0xf14e,  0xe16f,
    0x1080,  0x00a1,  0x30c2,  0x20e3,  0x5004,  0x4025,  0x7046,  0x6067,
    0x83b9,  0x9398,  0xa3fb,  0xb3da,  0xc33d,  0xd31c,  0xe37f,  0xf35e,
    0x02b1,  0x1290,  0x22f3,  0x32d2,  0x4235,  0x5214,  0x6277,  0x7256,
    0xb5ea,  0xa5cb,  0x95a8,  0x8589,  0xf56e,  0xe54f,  0xd52c,  0xc50d,
    0x34e2,  0x24c3,  0x14a0,  0x0481,  0x7466,  0x6447,  0x5424,  0x4405,
    0xa7db,  0xb7fa,  0x8799,  0x97b8,  0xe75f,  0xf77e,  0xc71d,  0xd73c,
    0x26d3,  0x36f2,  0x0691,  0x16b0,  0x6657,  0x7676,  0x4615,  0x5634,
    0xd94c,  0xc96d,  0xf90e,  0xe92f,  0x99c8,  0x89e9,  0xb98a,  0xa9ab,
    0x5844,  0x4865,  0x7806,  0x6827,  0x18c0,  0x08e1,  0x3882,  0x28a3,
    0xcb7d,  0xdb5c,  0xeb3f,  0xfb1e,  0x8bf9,  0x9bd8,  0xabbb,  0xbb9a,
    0x4a75,  0x5a54,  0x6a37,  0x7a16,  0x0af1,  0x1ad0,  0x2ab3,  0x3a92,
    0xfd2e,  0xed0f,  0xdd6c,  0xcd4d,  0xbdaa,  0xad8b,  0x9de8,  0x8dc9,
    0x7c26,  0x6c07,  0x5c64,  0x4c45,  0x3ca2,  0x2c83,  0x1ce0,  0x0cc1,
    0xef1f,  0xff3e,  0xcf5d,  0xdf7c,  0xaf9b,  0xbfba,  0x8fd9,  0x9ff8,
    0x6e17,  0x7e36,  0x4e55,  0x5e74,  0x2e93,  0x3eb2,  0x0ed1,  0x1ef0
	};

/*
 * updcrc macro derived from article Copyright (C) 1986 Stephen Satchell. 
 *  NOTE: First srgument must be in range 0 to 255.
 *        Second argument is referenced twice.
 * 
 * Programmers may incorporate any or all code into their programs, 
 * giving proper credit within the source. Publication of the 
 * source routines is permitted so long as proper credit is given 
 * to Stephen Satchell, Satchell Evaluations and Chuck Forsberg, 
 * Omen Technology.
 */

#if	0					/* defined in rbsb.h								*/
#define updcrc(cp, crc) (_crctab[((crc >> 8) & 255)] ^ (crc << 8) ^ cp)
#endif

/*
 * Copyright (C) 1986 Gary S. Brown.  You may use this program, or
 * code or tables extracted from it, as desired without restriction.
 */

/* First, the polynomial itself and its table of feedback terms.  The  */
/* polynomial is                                                       */
/* X^32+X^26+X^23+X^22+X^16+X^12+X^11+X^10+X^8+X^7+X^5+X^4+X^2+X^1+X^0 */
/* Note that we take it "backwards" and put the highest-order term in  */
/* the lowest-order bit.  The X^32 term is "implied"; the LSB is the   */
/* X^31 term, etc.  The X^0 term (usually shown as "+1") results in    */
/* the MSB being 1.                                                    */

/* Note that the usual hardware shift register implementation, which   */
/* is what we're using (we're merely optimizing it by doing eight-bit  */
/* chunks at a time) shifts bits into the lowest-order term.  In our   */
/* implementation, that means shifting towards the right.  Why do we   */
/* do it this way?  Because the calculated CRC must be transmitted in  */
/* order from highest-order term to lowest-order term.  UARTs transmit */
/* characters in order from LSB to MSB.  By storing the CRC this way,  */
/* we hand it to the UART in the order low-byte to high-byte; the UART */
/* sends each low-bit to hight-bit; and the result is transmission bit */
/* by bit from highest- to lowest-order term without requiring any bit */
/* shuffling on our part.  Reception works similarly.                  */

/* The feedback terms table consists of 256, 32-bit entries.  Notes:   */
/*                                                                     */
/*     The table can be generated at runtime if desired; code to do so */
/*     is shown later.  It might not be obvious, but the feedback      */
/*     terms simply represent the results of eight shift/xor opera-    */
/*     tions for all combinations of data and CRC register values.     */
/*                                                                     */
/*     The values must be right-shifted by eight bits by the "updcrc"  */
/*     logic; the shift must be unsigned (bring in zeroes).  On some   */
/*     hardware you could probably optimize the shift in assembler by  */
/*     using byte-swap instructions.                                   */

unsigned long _cr3tab[] =
	{ /* CRC polynomial 0xedb88320 */
	0x00000000L, 0x77073096L, 0xee0e612cL, 0x990951baL,
	0x076dc419L, 0x706af48fL, 0xe963a535L, 0x9e6495a3L,
	0x0edb8832L, 0x79dcb8a4L, 0xe0d5e91eL, 0x97d2d988L,
	0x09b64c2bL, 0x7eb17cbdL, 0xe7b82d07L, 0x90bf1d91L,
	0x1db71064L, 0x6ab020f2L, 0xf3b97148L, 0x84be41deL,
	0x1adad47dL, 0x6ddde4ebL, 0xf4d4b551L, 0x83d385c7L,
	0x136c9856L, 0x646ba8c0L, 0xfd62f97aL, 0x8a65c9ecL,
	0x14015c4fL, 0x63066cd9L, 0xfa0f3d63L, 0x8d080df5L,
	0x3b6e20c8L, 0x4c69105eL, 0xd56041e4L, 0xa2677172L,
	0x3c03e4d1L, 0x4b04d447L, 0xd20d85fdL, 0xa50ab56bL,
	0x35b5a8faL, 0x42b2986cL, 0xdbbbc9d6L, 0xacbcf940L,
	0x32d86ce3L, 0x45df5c75L, 0xdcd60dcfL, 0xabd13d59L,
	0x26d930acL, 0x51de003aL, 0xc8d75180L, 0xbfd06116L,
	0x21b4f4b5L, 0x56b3c423L, 0xcfba9599L, 0xb8bda50fL,
	0x2802b89eL, 0x5f058808L, 0xc60cd9b2L, 0xb10be924L,
	0x2f6f7c87L, 0x58684c11L, 0xc1611dabL, 0xb6662d3dL,
	0x76dc4190L, 0x01db7106L, 0x98d220bcL, 0xefd5102aL,
	0x71b18589L, 0x06b6b51fL, 0x9fbfe4a5L, 0xe8b8d433L,
	0x7807c9a2L, 0x0f00f934L, 0x9609a88eL, 0xe10e9818L,
	0x7f6a0dbbL, 0x086d3d2dL, 0x91646c97L, 0xe6635c01L,
	0x6b6b51f4L, 0x1c6c6162L, 0x856530d8L, 0xf262004eL,
	0x6c0695edL, 0x1b01a57bL, 0x8208f4c1L, 0xf50fc457L,
	0x65b0d9c6L, 0x12b7e950L, 0x8bbeb8eaL, 0xfcb9887cL,
	0x62dd1ddfL, 0x15da2d49L, 0x8cd37cf3L, 0xfbd44c65L,
	0x4db26158L, 0x3ab551ceL, 0xa3bc0074L, 0xd4bb30e2L,
	0x4adfa541L, 0x3dd895d7L, 0xa4d1c46dL, 0xd3d6f4fbL,
	0x4369e96aL, 0x346ed9fcL, 0xad678846L, 0xda60b8d0L,
	0x44042d73L, 0x33031de5L, 0xaa0a4c5fL, 0xdd0d7cc9L,
	0x5005713cL, 0x270241aaL, 0xbe0b1010L, 0xc90c2086L,
	0x5768b525L, 0x206f85b3L, 0xb966d409L, 0xce61e49fL,
	0x5edef90eL, 0x29d9c998L, 0xb0d09822L, 0xc7d7a8b4L,
	0x59b33d17L, 0x2eb40d81L, 0xb7bd5c3bL, 0xc0ba6cadL,
	0xedb88320L, 0x9abfb3b6L, 0x03b6e20cL, 0x74b1d29aL,
	0xead54739L, 0x9dd277afL, 0x04db2615L, 0x73dc1683L,
	0xe3630b12L, 0x94643b84L, 0x0d6d6a3eL, 0x7a6a5aa8L,
	0xe40ecf0bL, 0x9309ff9dL, 0x0a00ae27L, 0x7d079eb1L,
	0xf00f9344L, 0x8708a3d2L, 0x1e01f268L, 0x6906c2feL,
	0xf762575dL, 0x806567cbL, 0x196c3671L, 0x6e6b06e7L,
	0xfed41b76L, 0x89d32be0L, 0x10da7a5aL, 0x67dd4accL,
	0xf9b9df6fL, 0x8ebeeff9L, 0x17b7be43L, 0x60b08ed5L,
	0xd6d6a3e8L, 0xa1d1937eL, 0x38d8c2c4L, 0x4fdff252L,
	0xd1bb67f1L, 0xa6bc5767L, 0x3fb506ddL, 0x48b2364bL,
	0xd80d2bdaL, 0xaf0a1b4cL, 0x36034af6L, 0x41047a60L,
	0xdf60efc3L, 0xa867df55L, 0x316e8eefL, 0x4669be79L,
	0xcb61b38cL, 0xbc66831aL, 0x256fd2a0L, 0x5268e236L,
	0xcc0c7795L, 0xbb0b4703L, 0x220216b9L, 0x5505262fL,
	0xc5ba3bbeL, 0xb2bd0b28L, 0x2bb45a92L, 0x5cb36a04L,
	0xc2d7ffa7L, 0xb5d0cf31L, 0x2cd99e8bL, 0x5bdeae1dL,
	0x9b64c2b0L, 0xec63f226L, 0x756aa39cL, 0x026d930aL,
	0x9c0906a9L, 0xeb0e363fL, 0x72076785L, 0x05005713L,
	0x95bf4a82L, 0xe2b87a14L, 0x7bb12baeL, 0x0cb61b38L,
	0x92d28e9bL, 0xe5d5be0dL, 0x7cdcefb7L, 0x0bdbdf21L,
	0x86d3d2d4L, 0xf1d4e242L, 0x68ddb3f8L, 0x1fda836eL,
	0x81be16cdL, 0xf6b9265bL, 0x6fb077e1L, 0x18b74777L,
	0x88085ae6L, 0xff0f6a70L, 0x66063bcaL, 0x11010b5cL,
	0x8f659effL, 0xf862ae69L, 0x616bffd3L, 0x166ccf45L,
	0xa00ae278L, 0xd70dd2eeL, 0x4e048354L, 0x3903b3c2L,
	0xa7672661L, 0xd06016f7L, 0x4969474dL, 0x3e6e77dbL,
	0xaed16a4aL, 0xd9d65adcL, 0x40df0b66L, 0x37d83bf0L,
	0xa9bcae53L, 0xdebb9ec5L, 0x47b2cf7fL, 0x30b5ffe9L,
	0xbdbdf21cL, 0xcabac28aL, 0x53b39330L, 0x24b4a3a6L,
	0xbad03605L, 0xcdd70693L, 0x54de5729L, 0x23d967bfL,
	0xb3667a2eL, 0xc4614ab8L, 0x5d681b02L, 0x2a6f2b94L,
	0xb40bbe37L, 0xc30c8ea1L, 0x5a05df1bL, 0x2d02ef8dL
	};

#if	0					/* defined in rbsb.h								*/
#ifdef NFGM
long UPDC32 (int b, long c)
	{
	return (_cr3tab[((int)c ^ b) & 0xff] ^ ((c >> 8) & 0x00FFFFFF));
	}	/* long UPDC32 (int b, long c) */

#else

#define UPDC32(b, c) (_cr3tab[((int)c ^ b) & 0xff] ^ ((c >> 8) & 0x00FFFFFF))
#endif
#endif
/* End of rbsb.c */
