db/os/os_seek.c

/*-
 * See the file LICENSE for redistribution information.
 *
 * Copyright (c) 1997, 1998
 *  Sleepycat Software.  All rights reserved.
 */

#include "config.h"

#ifndef lint
static const char sccsid[] = "@(#)os_seek.c 10.11 (Sleepycat) 10/12/98";
#endif /* not lint */

#ifndef NO_SYSTEM_INCLUDES
#include <sys/types.h>

#include <errno.h>
#include <unistd.h>
#endif

#include "db_int.h"
#include "os_jump.h"

/*
 * __os_seek --
 *  Seek to a page/byte offset in the file.
 *
 * PUBLIC: int __os_seek __P((int, size_t, db_pgno_t, u_int32_t, int, int));
 */
int
__os_seek(fd, pgsize, pageno, relative, isrewind, whence)
    int fd;
    size_t pgsize;
    db_pgno_t pageno;
    u_int32_t relative;
    int isrewind, whence;
{
    off_t offset;
    int ret;

    if (__db_jump.j_seek != NULL)
        ret = __db_jump.j_seek(fd,
            pgsize, pageno, relative, isrewind, whence);
    else {
        offset = (off_t)pgsize * pageno + relative;
        if (isrewind)
            offset = -offset;

        ret = lseek(fd, offset, whence);
    }
    return (ret == -1 ? errno : 0);
}