cmpkeys.c

免费的Sql数据库系统

/*
 * cmpkeys.c  - keys comparision
 *              Kernel of GNU SQL-server  
 *
 * This file is a part of GNU SQL Server
 *
 *  Copyright (c) 1996, 1997, Free Software Foundation, Inc
 *  Developed at the Institute of System Programming
 *  This file is written by  Vera Ponomarenko
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 *  Contacts:   [e-mail]
 *
 */

/* $Id: cmpkeys.c,v 1.246 1997/04/10 06:57:28 vera Exp $ */

#include "destrn.h"
#include "strml.h"
#include "fdcltrn.h"

int
cmpkeys (u2_t kn, u2_t * afn, struct des_field *df, char *pk1, char *pk2)
{
  u2_t kk, k, n1, n2;
  char *k1, *kval1, *k2, *kval2;
  i4_t v;

  if (pk1 == NULL)
    return (1);			/* The first is absent */
  if (pk2 == NULL)
    return (-1);		/* The second is absent */
  k1 = kval1 = pk1 + scscal (pk1);
  k2 = kval2 = pk2 + scscal (pk2);
  for (kk = 0; kk < kn && pk1 < k1 && pk2 < k2; pk1++, pk2++)
    for (k = 0; k < 7 && kk < kn; kk++, k++)
      if ((*pk1 & BITVL(k)) != 0)
	{
	  if ((*pk2 & BITVL(k)) != 0)
	    {			/* both are defined */
	      switch ((df + afn[kk])->field_type)
		{
		case T1B:
		  if ((v = f1b (kval1, kval2, size1b, size1b)) != 0)
		    return (v);
		  kval1++;
		  kval2++;
		  break;
		case T2B:
		  if ((v = f2b (kval1, kval2, size2b, size2b)) != 0)
		    return (v);
		  kval1 += size2b;
		  kval2 += size2b;
		  break;
		case T4B:
		  if ((v = f4b (kval1, kval2, size4b, size4b)) != 0)
		    return (v);
		  kval1 += size4b;
		  kval2 += size4b;
		  break;
		case TFLOAT:
		  if ((v = flcmp (kval1, kval2, size4b, size4b)) != 0)
		    return (v);
		  kval1 += size4b;
		  kval2 += size4b;
		  break;
		case TFL:
		  n1 = t2bunpack (kval1);
		  kval1 += size2b;
		  n2 = t2bunpack (kval2);
		  kval2 += size2b;
		  if ((v = ffloat (kval1, kval2, n1, n2)) != 0)
		    return (v);
		  kval1 += n1;
		  kval2 += n2;
		  break;
		case TCH:
		  n1 = t2bunpack (kval1);
		  kval1 += size2b;
		  n2 = t2bunpack (kval2);
		  kval2 += size2b;
		  if ((v = chcmp (kval1, kval2, n1, n2)) != 0)
		    return (v);
		  kval1 += n1;
		  kval2 += n2;
		  break;
		default:
		  printf ("TRN.cmpkeys: This data type is incorrect");
		  break;
		}
	    }
	  else
	    return (-1);	/* The second isn't defined */
	}
      else if ((*pk2 & BITVL(k)) != 0)
	return (1);		/* The first isn't defined */
  if (kk < kn)
    {
      if (pk1 == k1)
	{
	  if (pk2 == k2)
	    return (0);
	  else
	    return (1);
	}
      else
	return (-1);
    }
  return (0);
}

int
cmp2keys (u2_t type, char *pk1, char *pk2)
{
  switch (type)
    {
    case T2B:
      return (f2b (pk1, pk2, size2b, size2b));
      break;
    case T4B:
      return (f4b (pk1, pk2, size4b, size4b));
      break;
    default:
      printf ("TRN.cmp2keys: This data type is incorrect");
      break;
    }
  return (0);
}