/*-
 * See the file LICENSE for redistribution information.
 *
 * Copyright (c) 1997, 2012 Oracle and/or its affiliates.  All rights reserved.
 *
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code 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
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 *
 * $Id$
 */

#include "db_config.h"

#include "db_int.h"

/*
 * __os_seek --
 *	Seek to a page/byte offset in the file.
 */
int
__os_seek(env, fhp, pgno, pgsize, relative)
	ENV *env;
	DB_FH *fhp;
	db_pgno_t pgno;
	u_int32_t pgsize;
	off_t relative;
{
	/* Yes, this really is how Microsoft designed their API. */
	union {
		__int64 bigint;
		struct {
			unsigned long low;
			long high;
		};
	} offbytes;
	DB_ENV *dbenv;
	off_t offset;
	int ret;

	dbenv = env == NULL ? NULL : env->dbenv;

#if defined(HAVE_STATISTICS)
	++fhp->seek_count;
#endif

	offset = (off_t)pgsize * pgno + relative;

	if (dbenv != NULL && FLD_ISSET(dbenv->verbose, DB_VERB_FILEOPS_ALL))
		__db_msg(env, DB_STR_A("0038",
		    "fileops: seek %s to %lu", "%s %lu"),
		    fhp->name, (u_long)offset);

	offbytes.bigint = offset;
	ret = (SetFilePointer(fhp->handle, offbytes.low,
	    &offbytes.high, FILE_BEGIN) == (DWORD)-1) ? __os_get_syserr() : 0;

	if (ret == 0) {
		fhp->pgsize = pgsize;
		fhp->pgno = pgno;
		fhp->offset = relative;
	} else {
		__db_syserr(env, ret, DB_STR_A("0039",
		    "seek: %lu: (%lu * %lu) + %lu", "%lu %lu %lu %lu"),
		    (u_long)offset, (u_long)pgno,
		    (u_long)pgsize, (u_long)relative);
		ret = __os_posix_err(ret);
	}

	return (ret);
}