101 lines
3.3 KiB
C
101 lines
3.3 KiB
C
/****************************************************************************
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* libs/libc/stdio/lib_fseeko.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <sys/types.h>
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#include <stdio.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <errno.h>
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#include "libc.h"
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: fseeko
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*
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* Description:
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* The fseeko() function sets the file position indicator for the stream
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* pointed to by stream. The new position, measured in bytes, is obtained
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* by adding offset bytes to the position specified by whence. If whence is
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* set to SEEK_SET, SEEK_CUR, or SEEK_END, the offset is relative to the
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* start of the file, the current position indicator, or end-of-file,
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* respectively. A successful call to the fseeko() function clears the
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* end-of-file indicator for the stream and undoes any effects of the
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* ungetc(3) function on the same stream.
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*
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* Returned Value:
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* Zero on success; -1 on failure with errno set appropriately.
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*
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****************************************************************************/
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int fseeko(FAR FILE *stream, off_t offset, int whence)
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{
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#ifdef CONFIG_DEBUG_FEATURES
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/* Verify that we were provided with a stream */
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if (!stream)
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{
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set_errno(EBADF);
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return ERROR;
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}
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#endif
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#ifndef CONFIG_STDIO_DISABLE_BUFFERING
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/* Flush any valid read/write data in the buffer (also verifies stream) */
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flockfile(stream);
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if (lib_rdflush_unlocked(stream) < 0 || lib_wrflush_unlocked(stream) < 0)
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{
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funlockfile(stream);
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return ERROR;
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}
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funlockfile(stream);
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#endif
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/* On success or failure, discard any characters saved by ungetc() */
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#if CONFIG_NUNGET_CHARS > 0
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stream->fs_nungotten = 0;
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#endif
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/* Perform the fseeko on the underlying file descriptor */
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if (stream->fs_iofunc.seek != NULL)
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{
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return stream->fs_iofunc.seek(stream->fs_cookie, &offset,
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whence) == (off_t)-1 ? ERROR : OK;
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}
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else
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{
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return lseek((int)(intptr_t)stream->fs_cookie, offset,
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whence) == (off_t)-1 ? ERROR : OK;
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}
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}
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