mirror of
https://github.com/FFmpeg/FFmpeg.git
synced 2026-11-06 13:28:17 +00:00
Kacper Michajłow
dea75789c3
av_file_map() maps a private copy of a file by name. Code that shares a file between processes needs the opposite, a writable mapping backed by the file, of a descriptor it opened itself, that grows with the file. Provide it with mmap() on POSIX and with a file mapping object on Windows, which also extends the file to the requested size. Signed-off-by: Kacper Michajłow <kasper93@gmail.com>
92 lines
3.3 KiB
C
92 lines
3.3 KiB
C
/*
|
|
* This file is part of FFmpeg.
|
|
*
|
|
* FFmpeg is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU Lesser General Public
|
|
* License as published by the Free Software Foundation; either
|
|
* version 2.1 of the License, or (at your option) any later version.
|
|
*
|
|
* FFmpeg 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
|
|
* Lesser General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU Lesser General Public
|
|
* License along with FFmpeg; if not, write to the Free Software
|
|
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
|
|
*/
|
|
|
|
#ifndef AVUTIL_FILE_H
|
|
#define AVUTIL_FILE_H
|
|
|
|
#include <stddef.h>
|
|
#include <stdint.h>
|
|
|
|
#include "attributes.h"
|
|
|
|
/**
|
|
* @file
|
|
* Misc file utilities.
|
|
*/
|
|
|
|
/**
|
|
* Read the file with name filename, and put its content in a newly
|
|
* allocated buffer or map it with mmap() when available.
|
|
* In case of success set *bufptr to the read or mmapped buffer, and
|
|
* *size to the size in bytes of the buffer in *bufptr.
|
|
* Unlike mmap this function succeeds with zero sized files, in this
|
|
* case *bufptr will be set to NULL and *size will be set to 0.
|
|
* The returned buffer must be released with av_file_unmap().
|
|
*
|
|
* @param filename path to the file
|
|
* @param[out] bufptr pointee is set to the mapped or allocated buffer
|
|
* @param[out] size pointee is set to the size in bytes of the buffer
|
|
* @param log_offset loglevel offset used for logging
|
|
* @param log_ctx context used for logging
|
|
* @return a non negative number in case of success, a negative value
|
|
* corresponding to an AVERROR error code in case of failure
|
|
*/
|
|
av_warn_unused_result
|
|
int av_file_map(const char *filename, uint8_t **bufptr, size_t *size,
|
|
int log_offset, void *log_ctx);
|
|
|
|
/**
|
|
* Unmap or free the buffer bufptr created by av_file_map().
|
|
*
|
|
* @param bufptr the buffer previously created with av_file_map()
|
|
* @param size size in bytes of bufptr, must be the same as returned
|
|
* by av_file_map()
|
|
*/
|
|
void av_file_unmap(uint8_t *bufptr, size_t size);
|
|
|
|
/**
|
|
* Map the beginning of an open file into memory for shared read and write
|
|
* access.
|
|
*
|
|
* Unlike av_file_map() the mapping is not a private copy of the file, every
|
|
* store to the returned memory is written to the file and is visible to
|
|
* every other mapping of it, in this process and in other processes. The
|
|
* file is extended to size bytes if it is shorter, it is never shortened.
|
|
* The mapping must be released with av_file_unmap_shared().
|
|
*
|
|
* @param fd file descriptor of a file opened for reading and writing
|
|
* @param size number of bytes to map, must not be zero
|
|
* @param[out] bufptr pointee is set to the mapped memory
|
|
* @return 0 in case of success, a negative value corresponding to an
|
|
* AVERROR error code in case of failure, AVERROR(ENOSYS) when the platform
|
|
* has no shared file mappings
|
|
*/
|
|
av_warn_unused_result
|
|
int av_file_map_shared(int fd, size_t size, void **bufptr);
|
|
|
|
/**
|
|
* Unmap the memory mapped by av_file_map_shared().
|
|
*
|
|
* @param bufptr the memory previously mapped by av_file_map_shared()
|
|
* @param size size in bytes of the mapping, must be the same as passed
|
|
* to av_file_map_shared()
|
|
*/
|
|
void av_file_unmap_shared(void *bufptr, size_t size);
|
|
|
|
#endif /* AVUTIL_FILE_H */
|