You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
 
 
 
 
mbed-classic/api/FileHandle.h

119 lines
3.3 KiB

/* 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>
#if defined(__ARMCC_VERSION) || defined(__ICCARM__)
typedef int ssize_t;
typedef long off_t;
#else
# include <sys/types.h>
#endif
namespace mbed {
/** An OO equivalent of the internal FILEHANDLE variable
* and associated _sys_* functions.
*
* FileHandle is an abstract class, needing at least sys_write and
* sys_read to be implmented for a simple interactive device.
*
* No one ever directly tals to/instanciates a FileHandle - it gets
* created by FileSystem, and wrapped up by stdio.
*/
class FileHandle {
public:
/** Write the contents of a buffer to the file
*
* @param buffer the buffer to write from
* @param length the number of characters to write
*
* @returns
* The number of characters written (possibly 0) on success, -1 on error.
*/
virtual ssize_t write(const void* buffer, size_t length) = 0;
/** Close the file
*
* @returns
* Zero on success, -1 on error.
*/
virtual int close() = 0;
/** Function read
* Reads the contents of the file into a buffer
*
* @param buffer the buffer to read in to
* @param length the number of characters to read
*
* @returns
* The number of characters read (zero at end of file) on success, -1 on error.
*/
virtual ssize_t read(void* buffer, size_t length) = 0;
/** Check if the handle is for a interactive terminal device.
* If so, line buffered behaviour is used by default
*
* @returns
* 1 if it is a terminal,
* 0 otherwise
*/
virtual int isatty() = 0;
/** 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
*/
virtual off_t lseek(off_t offset, int whence) = 0;
/** 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
*/
virtual int fsync() = 0;
virtual off_t flen() {
/* remember our current position */
off_t pos = lseek(0, SEEK_CUR);
if(pos == -1) return -1;
/* seek to the end to get the file length */
off_t res = lseek(0, SEEK_END);
/* return to our old position */
lseek(pos, SEEK_SET);
return res;
}
virtual ~FileHandle();
};
} // namespace mbed
#endif