static char *RCSid = "$Header: arcsvc.c,v 1.2 86/07/15 07:54:19 turner Exp $";

/*
 * $Log:	arcsvc.c,v $
 * Hack-attack 1.3  86/12/20  01:23:45  wilhite@usceast.uucp
 * 	Bludgeoned into submission for VAX 11/780 BSD4.2
 *	(ugly code, but fewer core dumps)
 *
 * Revision 1.2  86/07/15  07:54:19  turner
 *
 *
 * Revision 1.1  86/06/26  15:00:57  turner
 * initial version
 *
 *
 */

/*  ARC - Archive utility - ARCSVC

$define(tag,$$segment(@1,$$index(@1,=)+1))#
$define(version,Version $tag(
TED_VERSION DB =2.15), created on $tag(
TED_DATE DB =12/17/85) at $tag(
TED_TIME DB =15:17:16))#
$undefine(tag)#
    $version

(C) COPYRIGHT 1985 by System Enhancement Associates; ALL RIGHTS RESERVED

    By:  Thom Henderson

    Description:
         This file contains service routines needed to maintain an archive.

    Language:
         Computer Innovations Optimizing C86
*/
#include <stdio.h>
#include "arc.h"

#ifdef VAXC
#include <ssdef.h>
#include <descrip.h>

#ifdef abc123
INT rename(from,to)
char *from;
char *to;
{
	int lib$rename();
	int ret_val = 0;
	int rms_status;
	struct dsc$descriptor_s from_desc;
	struct dsc$descriptor_s to_desc;

	from_desc.dsc$w_length = strlen(from);
	from_desc.dsc$a_pointer = from;
	from_desc.dsc$b_class = DSC$K_CLASS_S;
	from_desc.dsc$b_dtype = DSC$K_DTYPE_T;

	to_desc.dsc$w_length = strlen(to);
	to_desc.dsc$a_pointer = to;
	to_desc.dsc$b_class = DSC$K_CLASS_S;
	to_desc.dsc$b_dtype = DSC$K_DTYPE_T;

	rms_status = lib$rename_file(&from_desc,&to_desc);
	if (rms_status != SS$_NORMAL) ret_val = rms_status;
	return(ret_val);
}
#endif
#endif

INT openarc(chg)                           /* open archive */
INT chg;                               /* true to open for changes */
{
    FILE *fopen();                     /* file opener */

    if(!(arc=fopen(arcname,"r")))
    {    if(chg)
              printf("Creating new archive: %s\n",arcname);
         else abort("Cannot read archive: %s",arcname);
    }

    if(chg)                            /* if opening for changes */
#ifdef VAXC
         if(!(new=fopen(newname,"w")))
/*         if(!(new=fopen(newname,"w","rfm=fix","mrs=512","rat=cr"))) */
#else
         if(!(new=fopen(newname,"w")))
#endif VAXC
              abort("Cannot create archive copy: %s",newname);
}

INT closearc(chg)                          /* close an archive */
INT chg;                               /* true if archive was changed */
{
    if(arc)                            /* if we had an initial archive */
         fclose(arc);                  /* then close it */

    if(chg)                            /* if things have changed */
    {    setstamp(new,arcdate,arctime);/* archive matches newest file */
         fclose(new);                  /* close the new copy */

         if(arc)                       /* if we had an original archive */
         {    if(keepbak)              /* if a backup is wanted */
              {    unlink(bakname);    /* erase any old copies */
                   if(rename(arcname,bakname))
                        abort("Cannot rename %s to %s",arcname,bakname);
                   printf("Keeping backup archive: %s\n",bakname);
              }
              else if(unlink(arcname))
                   abort("Cannot delete old archive: %s",arcname);
         }

         if(rename(newname,arcname))
              abort("Cannot rename %s to %s",newname,arcname);
    }
}

/* CRC computation logic

   The logic for this method of calculating the CRC 16 bit polynomial
   is taken from an article by David Schwaderer in the April 1985
   issue of PC Tech Journal.
*/

static INT crctab[] =                  /* CRC lookup table */
{   0x0000, 0xC0C1, 0xC181, 0x0140, 0xC301, 0x03C0, 0x0280, 0xC241,
    0xC601, 0x06C0, 0x0780, 0xC741, 0x0500, 0xC5C1, 0xC481, 0x0440,
    0xCC01, 0x0CC0, 0x0D80, 0xCD41, 0x0F00, 0xCFC1, 0xCE81, 0x0E40,
    0x0A00, 0xCAC1, 0xCB81, 0x0B40, 0xC901, 0x09C0, 0x0880, 0xC841,
    0xD801, 0x18C0, 0x1980, 0xD941, 0x1B00, 0xDBC1, 0xDA81, 0x1A40,
    0x1E00, 0xDEC1, 0xDF81, 0x1F40, 0xDD01, 0x1DC0, 0x1C80, 0xDC41,
    0x1400, 0xD4C1, 0xD581, 0x1540, 0xD701, 0x17C0, 0x1680, 0xD641,
    0xD201, 0x12C0, 0x1380, 0xD341, 0x1100, 0xD1C1, 0xD081, 0x1040,
    0xF001, 0x30C0, 0x3180, 0xF141, 0x3300, 0xF3C1, 0xF281, 0x3240,
    0x3600, 0xF6C1, 0xF781, 0x3740, 0xF501, 0x35C0, 0x3480, 0xF441,
    0x3C00, 0xFCC1, 0xFD81, 0x3D40, 0xFF01, 0x3FC0, 0x3E80, 0xFE41,
    0xFA01, 0x3AC0, 0x3B80, 0xFB41, 0x3900, 0xF9C1, 0xF881, 0x3840,
    0x2800, 0xE8C1, 0xE981, 0x2940, 0xEB01, 0x2BC0, 0x2A80, 0xEA41,
    0xEE01, 0x2EC0, 0x2F80, 0xEF41, 0x2D00, 0xEDC1, 0xEC81, 0x2C40,
    0xE401, 0x24C0, 0x2580, 0xE541, 0x2700, 0xE7C1, 0xE681, 0x2640,
    0x2200, 0xE2C1, 0xE381, 0x2340, 0xE101, 0x21C0, 0x2080, 0xE041,
    0xA001, 0x60C0, 0x6180, 0xA141, 0x6300, 0xA3C1, 0xA281, 0x6240,
    0x6600, 0xA6C1, 0xA781, 0x6740, 0xA501, 0x65C0, 0x6480, 0xA441,
    0x6C00, 0xACC1, 0xAD81, 0x6D40, 0xAF01, 0x6FC0, 0x6E80, 0xAE41,
    0xAA01, 0x6AC0, 0x6B80, 0xAB41, 0x6900, 0xA9C1, 0xA881, 0x6840,
    0x7800, 0xB8C1, 0xB981, 0x7940, 0xBB01, 0x7BC0, 0x7A80, 0xBA41,
    0xBE01, 0x7EC0, 0x7F80, 0xBF41, 0x7D00, 0xBDC1, 0xBC81, 0x7C40,
    0xB401, 0x74C0, 0x7580, 0xB541, 0x7700, 0xB7C1, 0xB681, 0x7640,
    0x7200, 0xB2C1, 0xB381, 0x7340, 0xB101, 0x71C0, 0x7080, 0xB041,
    0x5000, 0x90C1, 0x9181, 0x5140, 0x9301, 0x53C0, 0x5280, 0x9241,
    0x9601, 0x56C0, 0x5780, 0x9741, 0x5500, 0x95C1, 0x9481, 0x5440,
    0x9C01, 0x5CC0, 0x5D80, 0x9D41, 0x5F00, 0x9FC1, 0x9E81, 0x5E40,
    0x5A00, 0x9AC1, 0x9B81, 0x5B40, 0x9901, 0x59C0, 0x5880, 0x9841,
    0x8801, 0x48C0, 0x4980, 0x8941, 0x4B00, 0x8BC1, 0x8A81, 0x4A40,
    0x4E00, 0x8EC1, 0x8F81, 0x4F40, 0x8D01, 0x4DC0, 0x4C80, 0x8C41,
    0x4400, 0x84C1, 0x8581, 0x4540, 0x8701, 0x47C0, 0x4680, 0x8641,
    0x8201, 0x42C0, 0x4380, 0x8341, 0x4100, 0x81C1, 0x8081, 0x4040
};
INT addcrc(crc,c)                      /* update a CRC check */
INT crc;                               /* running CRC value */
unsigned char c;                       /* character to add */
{
    return (((crc>>8)&0x00ff) ^ crctab[(crc^c)&0x00ff]) & 0x0000ffff;
}