mirror of https://github.com/ARMmbed/mbed-os.git
145 lines
3.7 KiB
C++
145 lines
3.7 KiB
C++
/* mbed Microcontroller Library
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* Copyright (c) 2006-2013 ARM Limited
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* 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,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef MBED_FILEHANDLE_H
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#define MBED_FILEHANDLE_H
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typedef int FILEHANDLE;
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#include <stdio.h>
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#if defined(__ARMCC_VERSION) || defined(__ICCARM__)
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typedef int ssize_t;
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typedef long off_t;
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#else
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# include <sys/types.h>
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#endif
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namespace mbed {
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/** \addtogroup drivers */
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/** @{*/
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/** An OO equivalent of the internal FILEHANDLE variable
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* and associated _sys_* functions.
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*
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* FileHandle is an abstract class, needing at least sys_write and
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* sys_read to be implmented for a simple interactive device.
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*
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* No one ever directly tals to/instanciates a FileHandle - it gets
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* created by FileSystem, and wrapped up by stdio.
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*
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* @Note Synchronization level: Set by subclass
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*/
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class FileHandle {
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public:
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/** Write the contents of a buffer to the file
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*
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* @param buffer the buffer to write from
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* @param length the number of characters to write
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*
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* @returns
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* The number of characters written (possibly 0) on success, -1 on error.
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*/
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virtual ssize_t write(const void* buffer, size_t length) = 0;
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/** Close the file
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*
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* @returns
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* Zero on success, -1 on error.
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*/
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virtual int close() = 0;
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/** Function read
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* Reads the contents of the file into a buffer
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*
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* @param buffer the buffer to read in to
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* @param length the number of characters to read
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*
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* @returns
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* The number of characters read (zero at end of file) on success, -1 on error.
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*/
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virtual ssize_t read(void* buffer, size_t length) = 0;
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/** Check if the handle is for a interactive terminal device.
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* If so, line buffered behaviour is used by default
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*
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* @returns
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* 1 if it is a terminal,
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* 0 otherwise
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*/
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virtual int isatty() = 0;
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/** Move the file position to a given offset from a given location.
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*
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* @param offset The offset from whence to move to
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* @param whence SEEK_SET for the start of the file, SEEK_CUR for the
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* current file position, or SEEK_END for the end of the file.
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*
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* @returns
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* new file position on success,
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* -1 on failure or unsupported
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*/
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virtual off_t lseek(off_t offset, int whence) = 0;
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/** Flush any buffers associated with the FileHandle, ensuring it
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* is up to date on disk
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*
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* @returns
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* 0 on success or un-needed,
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* -1 on error
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*/
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virtual int fsync() = 0;
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virtual off_t flen() {
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lock();
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/* remember our current position */
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off_t pos = lseek(0, SEEK_CUR);
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if(pos == -1) {
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unlock();
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return -1;
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}
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/* seek to the end to get the file length */
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off_t res = lseek(0, SEEK_END);
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/* return to our old position */
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lseek(pos, SEEK_SET);
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unlock();
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return res;
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}
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virtual ~FileHandle();
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protected:
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/** Acquire exclusive access to this object.
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*/
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virtual void lock() {
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// Stub
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}
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/** Release exclusive access to this object.
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*/
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virtual void unlock() {
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// Stub
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}
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};
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} // namespace mbed
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#endif
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/** @}*/
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