joey shelton / LED_Demo2

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Dependencies:   MAX44000 PWM_Tone_Library nexpaq_mdk

Fork of LED_Demo by joey shelton

mbd_os/hal/api/FileHandle.h@1:55a6170b404f, 2016-09-17 (annotated)

Committer:
nexpaq
Date:
Sat Sep 17 16:32:05 2016 +0000
Revision:
1:55a6170b404f
checking in for sharing

Who changed what in which revision?

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nexpaq 1:55a6170b404f 1 /* mbed Microcontroller Library
nexpaq 1:55a6170b404f 2 * Copyright (c) 2006-2013 ARM Limited
nexpaq 1:55a6170b404f 3 *
nexpaq 1:55a6170b404f 4 * Licensed under the Apache License, Version 2.0 (the "License");
nexpaq 1:55a6170b404f 5 * you may not use this file except in compliance with the License.
nexpaq 1:55a6170b404f 6 * You may obtain a copy of the License at
nexpaq 1:55a6170b404f 7 *
nexpaq 1:55a6170b404f 8 * http://www.apache.org/licenses/LICENSE-2.0
nexpaq 1:55a6170b404f 9 *
nexpaq 1:55a6170b404f 10 * Unless required by applicable law or agreed to in writing, software
nexpaq 1:55a6170b404f 11 * distributed under the License is distributed on an "AS IS" BASIS,
nexpaq 1:55a6170b404f 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
nexpaq 1:55a6170b404f 13 * See the License for the specific language governing permissions and
nexpaq 1:55a6170b404f 14 * limitations under the License.
nexpaq 1:55a6170b404f 15 */
nexpaq 1:55a6170b404f 16 #ifndef MBED_FILEHANDLE_H
nexpaq 1:55a6170b404f 17 #define MBED_FILEHANDLE_H
nexpaq 1:55a6170b404f 18
nexpaq 1:55a6170b404f 19 typedef int FILEHANDLE;
nexpaq 1:55a6170b404f 20
nexpaq 1:55a6170b404f 21 #include <stdio.h>
nexpaq 1:55a6170b404f 22
nexpaq 1:55a6170b404f 23 #if defined(__ARMCC_VERSION) || defined(__ICCARM__)
nexpaq 1:55a6170b404f 24 typedef int ssize_t;
nexpaq 1:55a6170b404f 25 typedef long off_t;
nexpaq 1:55a6170b404f 26
nexpaq 1:55a6170b404f 27 #else
nexpaq 1:55a6170b404f 28 # include <sys/types.h>
nexpaq 1:55a6170b404f 29 #endif
nexpaq 1:55a6170b404f 30
nexpaq 1:55a6170b404f 31 namespace mbed {
nexpaq 1:55a6170b404f 32
nexpaq 1:55a6170b404f 33 /** An OO equivalent of the internal FILEHANDLE variable
nexpaq 1:55a6170b404f 34 * and associated _sys_* functions.
nexpaq 1:55a6170b404f 35 *
nexpaq 1:55a6170b404f 36 * FileHandle is an abstract class, needing at least sys_write and
nexpaq 1:55a6170b404f 37 * sys_read to be implmented for a simple interactive device.
nexpaq 1:55a6170b404f 38 *
nexpaq 1:55a6170b404f 39 * No one ever directly tals to/instanciates a FileHandle - it gets
nexpaq 1:55a6170b404f 40 * created by FileSystem, and wrapped up by stdio.
nexpaq 1:55a6170b404f 41 *
nexpaq 1:55a6170b404f 42 * @Note Synchronization level: Set by subclass
nexpaq 1:55a6170b404f 43 */
nexpaq 1:55a6170b404f 44 class FileHandle {
nexpaq 1:55a6170b404f 45
nexpaq 1:55a6170b404f 46 public:
nexpaq 1:55a6170b404f 47 /** Write the contents of a buffer to the file
nexpaq 1:55a6170b404f 48 *
nexpaq 1:55a6170b404f 49 * @param buffer the buffer to write from
nexpaq 1:55a6170b404f 50 * @param length the number of characters to write
nexpaq 1:55a6170b404f 51 *
nexpaq 1:55a6170b404f 52 * @returns
nexpaq 1:55a6170b404f 53 * The number of characters written (possibly 0) on success, -1 on error.
nexpaq 1:55a6170b404f 54 */
nexpaq 1:55a6170b404f 55 virtual ssize_t write(const void* buffer, size_t length) = 0;
nexpaq 1:55a6170b404f 56
nexpaq 1:55a6170b404f 57 /** Close the file
nexpaq 1:55a6170b404f 58 *
nexpaq 1:55a6170b404f 59 * @returns
nexpaq 1:55a6170b404f 60 * Zero on success, -1 on error.
nexpaq 1:55a6170b404f 61 */
nexpaq 1:55a6170b404f 62 virtual int close() = 0;
nexpaq 1:55a6170b404f 63
nexpaq 1:55a6170b404f 64 /** Function read
nexpaq 1:55a6170b404f 65 * Reads the contents of the file into a buffer
nexpaq 1:55a6170b404f 66 *
nexpaq 1:55a6170b404f 67 * @param buffer the buffer to read in to
nexpaq 1:55a6170b404f 68 * @param length the number of characters to read
nexpaq 1:55a6170b404f 69 *
nexpaq 1:55a6170b404f 70 * @returns
nexpaq 1:55a6170b404f 71 * The number of characters read (zero at end of file) on success, -1 on error.
nexpaq 1:55a6170b404f 72 */
nexpaq 1:55a6170b404f 73 virtual ssize_t read(void* buffer, size_t length) = 0;
nexpaq 1:55a6170b404f 74
nexpaq 1:55a6170b404f 75 /** Check if the handle is for a interactive terminal device.
nexpaq 1:55a6170b404f 76 * If so, line buffered behaviour is used by default
nexpaq 1:55a6170b404f 77 *
nexpaq 1:55a6170b404f 78 * @returns
nexpaq 1:55a6170b404f 79 * 1 if it is a terminal,
nexpaq 1:55a6170b404f 80 * 0 otherwise
nexpaq 1:55a6170b404f 81 */
nexpaq 1:55a6170b404f 82 virtual int isatty() = 0;
nexpaq 1:55a6170b404f 83
nexpaq 1:55a6170b404f 84 /** Move the file position to a given offset from a given location.
nexpaq 1:55a6170b404f 85 *
nexpaq 1:55a6170b404f 86 * @param offset The offset from whence to move to
nexpaq 1:55a6170b404f 87 * @param whence SEEK_SET for the start of the file, SEEK_CUR for the
nexpaq 1:55a6170b404f 88 * current file position, or SEEK_END for the end of the file.
nexpaq 1:55a6170b404f 89 *
nexpaq 1:55a6170b404f 90 * @returns
nexpaq 1:55a6170b404f 91 * new file position on success,
nexpaq 1:55a6170b404f 92 * -1 on failure or unsupported
nexpaq 1:55a6170b404f 93 */
nexpaq 1:55a6170b404f 94 virtual off_t lseek(off_t offset, int whence) = 0;
nexpaq 1:55a6170b404f 95
nexpaq 1:55a6170b404f 96 /** Flush any buffers associated with the FileHandle, ensuring it
nexpaq 1:55a6170b404f 97 * is up to date on disk
nexpaq 1:55a6170b404f 98 *
nexpaq 1:55a6170b404f 99 * @returns
nexpaq 1:55a6170b404f 100 * 0 on success or un-needed,
nexpaq 1:55a6170b404f 101 * -1 on error
nexpaq 1:55a6170b404f 102 */
nexpaq 1:55a6170b404f 103 virtual int fsync() = 0;
nexpaq 1:55a6170b404f 104
nexpaq 1:55a6170b404f 105 virtual off_t flen() {
nexpaq 1:55a6170b404f 106 lock();
nexpaq 1:55a6170b404f 107 /* remember our current position */
nexpaq 1:55a6170b404f 108 off_t pos = lseek(0, SEEK_CUR);
nexpaq 1:55a6170b404f 109 if(pos == -1) {
nexpaq 1:55a6170b404f 110 unlock();
nexpaq 1:55a6170b404f 111 return -1;
nexpaq 1:55a6170b404f 112 }
nexpaq 1:55a6170b404f 113 /* seek to the end to get the file length */
nexpaq 1:55a6170b404f 114 off_t res = lseek(0, SEEK_END);
nexpaq 1:55a6170b404f 115 /* return to our old position */
nexpaq 1:55a6170b404f 116 lseek(pos, SEEK_SET);
nexpaq 1:55a6170b404f 117 unlock();
nexpaq 1:55a6170b404f 118 return res;
nexpaq 1:55a6170b404f 119 }
nexpaq 1:55a6170b404f 120
nexpaq 1:55a6170b404f 121 virtual ~FileHandle();
nexpaq 1:55a6170b404f 122
nexpaq 1:55a6170b404f 123 protected:
nexpaq 1:55a6170b404f 124
nexpaq 1:55a6170b404f 125 /** Acquire exclusive access to this object.
nexpaq 1:55a6170b404f 126 */
nexpaq 1:55a6170b404f 127 virtual void lock() {
nexpaq 1:55a6170b404f 128 // Stub
nexpaq 1:55a6170b404f 129 }
nexpaq 1:55a6170b404f 130
nexpaq 1:55a6170b404f 131 /** Release exclusive access to this object.
nexpaq 1:55a6170b404f 132 */
nexpaq 1:55a6170b404f 133 virtual void unlock() {
nexpaq 1:55a6170b404f 134 // Stub
nexpaq 1:55a6170b404f 135 }
nexpaq 1:55a6170b404f 136 };
nexpaq 1:55a6170b404f 137
nexpaq 1:55a6170b404f 138 } // namespace mbed
nexpaq 1:55a6170b404f 139
nexpaq 1:55a6170b404f 140 #endif