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- /* Copyright (c) 2000, 2021, Oracle and/or its affiliates.
-
- This program is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License, version 2.0,
- as published by the Free Software Foundation.
-
- This program is also distributed with certain software (including
- but not limited to OpenSSL) that is licensed under separate terms,
- as designated in a particular file or component or in included license
- documentation. The authors of MySQL hereby grant you an additional
- permission to link the program and your derivative works with the
- separately licensed software that they have included with MySQL.
-
- Without limiting anything contained in the foregoing, this file,
- which is part of C Driver for MySQL (Connector/C), is also subject to the
- Universal FOSS Exception, version 1.0, a copy of which can be found at
- http://oss.oracle.com/licenses/universal-foss-exception.
-
- 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, version 2.0, 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
-
- #include "mysys_priv.h"
- #include "my_sys.h"
- #include "mysys_err.h"
- #include "my_thread_local.h"
-
- /*
- Seek to a position in a file.
-
- ARGUMENTS
- File fd The file descriptor
- my_off_t pos The expected position (absolute or relative)
- int whence A direction parameter and one of
- {SEEK_SET, SEEK_CUR, SEEK_END}
- myf MyFlags MY_THREADSAFE must be set in case my_seek may be mixed
- with my_pread/my_pwrite calls and fd is shared among
- threads.
-
- DESCRIPTION
- The my_seek function is a wrapper around the system call lseek and
- repositions the offset of the file descriptor fd to the argument
- offset according to the directive whence as follows:
- SEEK_SET The offset is set to offset bytes.
- SEEK_CUR The offset is set to its current location plus offset bytes
- SEEK_END The offset is set to the size of the file plus offset bytes
-
- RETURN VALUE
- my_off_t newpos The new position in the file.
- MY_FILEPOS_ERROR An error was encountered while performing
- the seek. my_errno is set to indicate the
- actual error.
- */
-
- my_off_t my_seek(File fd, my_off_t pos, int whence, myf MyFlags)
- {
- os_off_t newpos= -1;
- DBUG_ENTER("my_seek");
- DBUG_PRINT("my",("fd: %d Pos: %llu Whence: %d MyFlags: %d",
- fd, (ulonglong) pos, whence, MyFlags));
-
- /*
- Make sure we are using a valid file descriptor!
- */
- assert(fd != -1);
- #if defined (_WIN32)
- newpos= my_win_lseek(fd, pos, whence);
- #else
- newpos= lseek(fd, pos, whence);
- #endif
- if (newpos == (os_off_t) -1)
- {
- set_my_errno(errno);
- if (MyFlags & MY_WME)
- {
- char errbuf[MYSYS_STRERROR_SIZE];
- my_error(EE_CANT_SEEK, MYF(0), my_filename(fd),
- my_errno(), my_strerror(errbuf, sizeof(errbuf), my_errno()));
- }
- DBUG_PRINT("error", ("lseek: %llu errno: %d", (ulonglong) newpos, errno));
- DBUG_RETURN(MY_FILEPOS_ERROR);
- }
- if ((my_off_t) newpos != pos)
- {
- DBUG_PRINT("exit",("pos: %llu", (ulonglong) newpos));
- }
- DBUG_RETURN((my_off_t) newpos);
- } /* my_seek */
-
-
- /* Tell current position of file */
- /* ARGSUSED */
-
- my_off_t my_tell(File fd, myf MyFlags)
- {
- os_off_t pos;
- DBUG_ENTER("my_tell");
- DBUG_PRINT("my",("fd: %d MyFlags: %d",fd, MyFlags));
- assert(fd >= 0);
- #if defined (HAVE_TELL) && !defined (_WIN32)
- pos= tell(fd);
- #else
- pos= my_seek(fd, 0L, MY_SEEK_CUR,0);
- #endif
- if (pos == (os_off_t) -1)
- {
- set_my_errno(errno);
- if (MyFlags & MY_WME)
- {
- char errbuf[MYSYS_STRERROR_SIZE];
- my_error(EE_CANT_SEEK, MYF(0), my_filename(fd),
- my_errno(), my_strerror(errbuf, sizeof(errbuf), my_errno()));
- }
- DBUG_PRINT("error", ("tell: %llu errno: %d", (ulonglong) pos, my_errno()));
- }
- DBUG_PRINT("exit",("pos: %llu", (ulonglong) pos));
- DBUG_RETURN((my_off_t) pos);
- } /* my_tell */
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