0a107ca6d9
This commit adds support for custom stream via fopencookie function. The function allows the programmer the create his own custom stream for IO operations and hook his custom functions to it. This is a non POSIX interface defined in Standard C library and implemented according to it. The only difference is in usage of off_t instead of off64_t. Programmer can use 64 bits offset if CONFIG_FS_LARGEFILE is enabled. In that case off_t is defined as int64_t (int32_t otherwise). Field fs_fd is removed from file_struct and fs_cookie is used instead as a shared variable for file descriptor or user defined cookie. The interface will be useful for future fmemopen implementation. Signed-off-by: Michal Lenc <michallenc@seznam.cz>
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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