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Shareware Overload Trio 2
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gnudbm14.zip
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UPDATE.C
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1990-08-24
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/* update.c - The routines for updating the file to a consistent state. */
/* This file is part of GDBM, the GNU data base manager, by Philip A. Nelson.
Copyright (C) 1990 Free Software Foundation, Inc.
GDBM 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 1, or (at your option)
any later version.
GDBM 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 GDBM; see the file COPYING. If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
You may contact the author by:
e-mail: phil@wwu.edu
us-mail: Philip A. Nelson
Computer Science Department
Western Washington University
Bellingham, WA 98226
phone: (206) 676-3035
*************************************************************************/
/*
* MS-DOS port (c) 1990 by Thorsten Ohl, td12@@ddagsi3.bitnet
*
* To this port, the same copying conditions apply as to the
* original release.
*
* IMPORTANT:
* This file is not identical to the original GNU release!
* You should have received this code as patch to the official
* GNU release.
*
* MORE IMPORTANT:
* This port comes with ABSOLUTELY NO WARRANTY.
*
* $Header: e:/gnu/gdbm/RCS/update.c'v 1.4.0.1 90/08/16 09:22:53 tho Exp $
*/
#include <stdio.h>
#include <sys/types.h>
#ifndef MSDOS
#include <sys/file.h>
#endif /* not MSDOS */
#include "gdbmdefs.h"
#include "systems.h"
#ifdef __STDC__
static void write_header (gdbm_file_info *dbf);
#endif /* __STDC__ */
/* This procedure writes the header back to the file described by DBF. */
static VOID
write_header (dbf)
gdbm_file_info *dbf;
{
LONG num_bytes;
num_bytes = lseek (dbf->desc, (LONG) 0, L_SET);
if (num_bytes != 0) _gdbm_fatal (dbf, "lseek error");
#ifdef MSDOS
num_bytes = write (dbf->desc, (char *) dbf->header, dbf->header->block_size);
#else /* not MSDOS */
num_bytes = write (dbf->desc, dbf->header, dbf->header->block_size);
#endif /* not MSDOS */
if (num_bytes != dbf->header->block_size)
_gdbm_fatal (dbf, "write error");
/* Wait for all output to be done. */
fsync (dbf->desc);
}
/* After all changes have been made in memory, we now write them
all to disk. */
VOID
_gdbm_end_update (dbf)
gdbm_file_info *dbf;
{
LONG num_bytes; /* Return value for lseek and write. */
/* Write the current bucket. */
if (dbf->bucket_changed)
{
_gdbm_write_bucket (dbf, dbf->cache_entry);
dbf->bucket_changed = FALSE;
}
/* Write the other changed buckets if there are any. */
if (dbf->second_changed)
{
int index;
for (index = 0; index < CACHE_SIZE; index++)
if (dbf->bucket_cache[index].ca_changed)
{
_gdbm_write_bucket (dbf, &dbf->bucket_cache[index]);
}
dbf->second_changed = FALSE;
}
/* Write the directory. */
if (dbf->directory_changed)
{
num_bytes = lseek (dbf->desc, dbf->header->dir, L_SET);
if (num_bytes != dbf->header->dir) _gdbm_fatal (dbf, "lseek error");
#ifdef MSDOS /* shut up the compiler! */
num_bytes = write (dbf->desc, (char *) dbf->dir, dbf->header->dir_size);
#else /* not MSDOS */
num_bytes = write (dbf->desc, dbf->dir, dbf->header->dir_size);
#endif /* not MSDOS */
if (num_bytes != dbf->header->dir_size)
_gdbm_fatal (dbf, "write error");
dbf->directory_changed = FALSE;
if (!dbf->header_changed) fsync (dbf->desc);
}
/* Final write of the header. */
if (dbf->header_changed)
{
write_header (dbf);
dbf->header_changed = FALSE;
}
}
/* If a fatal error is detected, come here and exit. VAL tells which fatal
error occured. */
VOID
_gdbm_fatal (dbf, val)
gdbm_file_info *dbf;
char *val;
{
if (dbf->fatal_err != NULL)
(*dbf->fatal_err) (val);
else
fprintf (stderr, "gdbm fatal: %s.\n", val);
exit (-1);
}