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FileHandle.h
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FileHandle.h
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/* mbed Microcontroller Library
* Copyright (c) 2006-2013 ARM Limited
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef MBED_FILEHANDLE_H
#define MBED_FILEHANDLE_H
typedef int FILEHANDLE;
#include <stdio.h>
#include "platform/platform.h"
namespace mbed {
/** \addtogroup platform */
/** Class FileHandle
*
* An abstract interface that represents operations on a file-like
* object. The core functions are read, write, and seek, but only
* a subset of these operations can be provided.
*
* @note to create a file, @see File
* @note Synchronization level: Set by subclass
* @ingroup platform
*/
class FileHandle {
public:
virtual ~FileHandle() {}
/** Read the contents of a file into a buffer
*
* @param buffer The buffer to read in to
* @param size The number of bytes to read
* @return The number of bytes read, 0 at end of file, negative error on failure
*/
virtual ssize_t read(void *buffer, size_t size) = 0;
/** Write the contents of a buffer to a file
*
* @param buffer The buffer to write from
* @param size The number of bytes to write
* @return The number of bytes written, negative error on failure
*/
virtual ssize_t write(const void *buffer, size_t size) = 0;
/** Move the file position to a given offset from from a given location
*
* @param offset The offset from whence to move to
* @param whence The start of where to seek
* SEEK_SET to start from beginning of file,
* SEEK_CUR to start from current position in file,
* SEEK_END to start from end of file
* @return The new offset of the file
*/
virtual off_t seek(off_t offset, int whence = SEEK_SET) = 0;
/** Close a file
*
* @return 0 on success, negative error code on failure
*/
virtual int close() = 0;
/** Flush any buffers associated with the file
*
* @return 0 on success, negative error code on failure
*/
virtual int sync()
{
return 0;
}
/** Check if the file in an interactive terminal device
*
* @return True if the file is a terminal
*/
virtual int isatty()
{
return false;
}
/** Get the file position of the file
*
* @note This is equivalent to seek(0, SEEK_CUR)
*
* @return The current offset in the file
*/
virtual off_t tell()
{
return seek(0, SEEK_CUR);
}
/** Rewind the file position to the beginning of the file
*
* @note This is equivalent to seek(0, SEEK_SET)
*/
virtual void rewind()
{
seek(0, SEEK_SET);
}
/** Get the size of the file
*
* @return Size of the file in bytes
*/
virtual off_t size()
{
off_t off = tell();
off_t size = seek(0, SEEK_END);
seek(off, SEEK_SET);
return size;
}
/** Move the file position to a given offset from a given location.
*
* @param offset The offset from whence to move to
* @param whence SEEK_SET for the start of the file, SEEK_CUR for the
* current file position, or SEEK_END for the end of the file.
*
* @returns
* new file position on success,
* -1 on failure or unsupported
*/
MBED_DEPRECATED_SINCE("mbed-os-5.4", "Replaced by FileHandle::seek")
virtual off_t lseek(off_t offset, int whence) { return seek(offset, whence); }
/** Flush any buffers associated with the FileHandle, ensuring it
* is up to date on disk
*
* @returns
* 0 on success or un-needed,
* -1 on error
*/
MBED_DEPRECATED_SINCE("mbed-os-5.4", "Replaced by FileHandle::sync")
virtual int fsync() { return sync(); }
/** Find the length of the file
*
* @returns
* Length of the file
*/
MBED_DEPRECATED_SINCE("mbed-os-5.4", "Replaced by FileHandle::size")
virtual off_t flen() { return size(); }
};
} // namespace mbed
#endif