Files
cpython-source-deps/os/os_seek.c
2017-09-04 13:40:25 -05:00

65 lines
1.3 KiB
C

/*-
* See the file LICENSE for redistribution information.
*
* Copyright (c) 1997,2008 Oracle. All rights reserved.
*
* $Id: os_seek.c 63573 2008-05-23 21:43:21Z trent.nelson $
*/
#include "db_config.h"
#include "db_int.h"
/*
* __os_seek --
* Seek to a page/byte offset in the file.
*
* PUBLIC: int __os_seek __P((ENV *,
* PUBLIC: DB_FH *, db_pgno_t, u_int32_t, u_int32_t));
*/
int
__os_seek(env, fhp, pgno, pgsize, relative)
ENV *env;
DB_FH *fhp;
db_pgno_t pgno;
u_int32_t pgsize;
u_int32_t relative;
{
DB_ENV *dbenv;
off_t offset;
int ret;
dbenv = env == NULL ? NULL : env->dbenv;
DB_ASSERT(env, F_ISSET(fhp, DB_FH_OPENED) && fhp->fd != -1);
#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,
"fileops: seek %s to %lu", fhp->name, (u_long)offset);
if (DB_GLOBAL(j_seek) != NULL)
ret = DB_GLOBAL(j_seek)(fhp->fd, offset, SEEK_SET);
else
RETRY_CHK((lseek(
fhp->fd, offset, SEEK_SET) == -1 ? 1 : 0), ret);
if (ret == 0) {
fhp->pgsize = pgsize;
fhp->pgno = pgno;
fhp->offset = relative;
} else {
__db_syserr(env, ret,
"seek: %lu: (%lu * %lu) + %lu", (u_long)offset,
(u_long)pgno, (u_long)pgsize, (u_long)relative);
ret = __os_posix_err(ret);
}
return (ret);
}