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mbed/FileHandle.h@3:78f223d34f36, 2019-03-05 (annotated)

Committer:
ethaderu
Date:
Tue Mar 05 02:34:44 2019 +0000
Revision:
3:78f223d34f36
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ethaderu 3:78f223d34f36 1 /* mbed Microcontroller Library
ethaderu 3:78f223d34f36 2 * Copyright (c) 2006-2013 ARM Limited
ethaderu 3:78f223d34f36 3 *
ethaderu 3:78f223d34f36 4 * Licensed under the Apache License, Version 2.0 (the "License");
ethaderu 3:78f223d34f36 5 * you may not use this file except in compliance with the License.
ethaderu 3:78f223d34f36 6 * You may obtain a copy of the License at
ethaderu 3:78f223d34f36 7 *
ethaderu 3:78f223d34f36 8 * http://www.apache.org/licenses/LICENSE-2.0
ethaderu 3:78f223d34f36 9 *
ethaderu 3:78f223d34f36 10 * Unless required by applicable law or agreed to in writing, software
ethaderu 3:78f223d34f36 11 * distributed under the License is distributed on an "AS IS" BASIS,
ethaderu 3:78f223d34f36 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
ethaderu 3:78f223d34f36 13 * See the License for the specific language governing permissions and
ethaderu 3:78f223d34f36 14 * limitations under the License.
ethaderu 3:78f223d34f36 15 */
ethaderu 3:78f223d34f36 16 #ifndef MBED_FILEHANDLE_H
ethaderu 3:78f223d34f36 17 #define MBED_FILEHANDLE_H
ethaderu 3:78f223d34f36 18
ethaderu 3:78f223d34f36 19 typedef int FILEHANDLE;
ethaderu 3:78f223d34f36 20
ethaderu 3:78f223d34f36 21 #include <stdio.h>
ethaderu 3:78f223d34f36 22
ethaderu 3:78f223d34f36 23 #if defined(__ARMCC_VERSION) || defined(__ICCARM__)
ethaderu 3:78f223d34f36 24 typedef int ssize_t;
ethaderu 3:78f223d34f36 25 typedef long off_t;
ethaderu 3:78f223d34f36 26
ethaderu 3:78f223d34f36 27 #else
ethaderu 3:78f223d34f36 28 # include <sys/types.h>
ethaderu 3:78f223d34f36 29 #endif
ethaderu 3:78f223d34f36 30
ethaderu 3:78f223d34f36 31 namespace mbed {
ethaderu 3:78f223d34f36 32
ethaderu 3:78f223d34f36 33 /** An OO equivalent of the internal FILEHANDLE variable
ethaderu 3:78f223d34f36 34 * and associated _sys_* functions.
ethaderu 3:78f223d34f36 35 *
ethaderu 3:78f223d34f36 36 * FileHandle is an abstract class, needing at least sys_write and
ethaderu 3:78f223d34f36 37 * sys_read to be implmented for a simple interactive device.
ethaderu 3:78f223d34f36 38 *
ethaderu 3:78f223d34f36 39 * No one ever directly tals to/instanciates a FileHandle - it gets
ethaderu 3:78f223d34f36 40 * created by FileSystem, and wrapped up by stdio.
ethaderu 3:78f223d34f36 41 */
ethaderu 3:78f223d34f36 42 class FileHandle {
ethaderu 3:78f223d34f36 43
ethaderu 3:78f223d34f36 44 public:
ethaderu 3:78f223d34f36 45 /** Write the contents of a buffer to the file
ethaderu 3:78f223d34f36 46 *
ethaderu 3:78f223d34f36 47 * @param buffer the buffer to write from
ethaderu 3:78f223d34f36 48 * @param length the number of characters to write
ethaderu 3:78f223d34f36 49 *
ethaderu 3:78f223d34f36 50 * @returns
ethaderu 3:78f223d34f36 51 * The number of characters written (possibly 0) on success, -1 on error.
ethaderu 3:78f223d34f36 52 */
ethaderu 3:78f223d34f36 53 virtual ssize_t write(const void* buffer, size_t length) = 0;
ethaderu 3:78f223d34f36 54
ethaderu 3:78f223d34f36 55 /** Close the file
ethaderu 3:78f223d34f36 56 *
ethaderu 3:78f223d34f36 57 * @returns
ethaderu 3:78f223d34f36 58 * Zero on success, -1 on error.
ethaderu 3:78f223d34f36 59 */
ethaderu 3:78f223d34f36 60 virtual int close() = 0;
ethaderu 3:78f223d34f36 61
ethaderu 3:78f223d34f36 62 /** Function read
ethaderu 3:78f223d34f36 63 * Reads the contents of the file into a buffer
ethaderu 3:78f223d34f36 64 *
ethaderu 3:78f223d34f36 65 * @param buffer the buffer to read in to
ethaderu 3:78f223d34f36 66 * @param length the number of characters to read
ethaderu 3:78f223d34f36 67 *
ethaderu 3:78f223d34f36 68 * @returns
ethaderu 3:78f223d34f36 69 * The number of characters read (zero at end of file) on success, -1 on error.
ethaderu 3:78f223d34f36 70 */
ethaderu 3:78f223d34f36 71 virtual ssize_t read(void* buffer, size_t length) = 0;
ethaderu 3:78f223d34f36 72
ethaderu 3:78f223d34f36 73 /** Check if the handle is for a interactive terminal device.
ethaderu 3:78f223d34f36 74 * If so, line buffered behaviour is used by default
ethaderu 3:78f223d34f36 75 *
ethaderu 3:78f223d34f36 76 * @returns
ethaderu 3:78f223d34f36 77 * 1 if it is a terminal,
ethaderu 3:78f223d34f36 78 * 0 otherwise
ethaderu 3:78f223d34f36 79 */
ethaderu 3:78f223d34f36 80 virtual int isatty() = 0;
ethaderu 3:78f223d34f36 81
ethaderu 3:78f223d34f36 82 /** Move the file position to a given offset from a given location.
ethaderu 3:78f223d34f36 83 *
ethaderu 3:78f223d34f36 84 * @param offset The offset from whence to move to
ethaderu 3:78f223d34f36 85 * @param whence SEEK_SET for the start of the file, SEEK_CUR for the
ethaderu 3:78f223d34f36 86 * current file position, or SEEK_END for the end of the file.
ethaderu 3:78f223d34f36 87 *
ethaderu 3:78f223d34f36 88 * @returns
ethaderu 3:78f223d34f36 89 * new file position on success,
ethaderu 3:78f223d34f36 90 * -1 on failure or unsupported
ethaderu 3:78f223d34f36 91 */
ethaderu 3:78f223d34f36 92 virtual off_t lseek(off_t offset, int whence) = 0;
ethaderu 3:78f223d34f36 93
ethaderu 3:78f223d34f36 94 /** Flush any buffers associated with the FileHandle, ensuring it
ethaderu 3:78f223d34f36 95 * is up to date on disk
ethaderu 3:78f223d34f36 96 *
ethaderu 3:78f223d34f36 97 * @returns
ethaderu 3:78f223d34f36 98 * 0 on success or un-needed,
ethaderu 3:78f223d34f36 99 * -1 on error
ethaderu 3:78f223d34f36 100 */
ethaderu 3:78f223d34f36 101 virtual int fsync() = 0;
ethaderu 3:78f223d34f36 102
ethaderu 3:78f223d34f36 103 virtual off_t flen() {
ethaderu 3:78f223d34f36 104 /* remember our current position */
ethaderu 3:78f223d34f36 105 off_t pos = lseek(0, SEEK_CUR);
ethaderu 3:78f223d34f36 106 if(pos == -1) return -1;
ethaderu 3:78f223d34f36 107 /* seek to the end to get the file length */
ethaderu 3:78f223d34f36 108 off_t res = lseek(0, SEEK_END);
ethaderu 3:78f223d34f36 109 /* return to our old position */
ethaderu 3:78f223d34f36 110 lseek(pos, SEEK_SET);
ethaderu 3:78f223d34f36 111 return res;
ethaderu 3:78f223d34f36 112 }
ethaderu 3:78f223d34f36 113
ethaderu 3:78f223d34f36 114 virtual ~FileHandle();
ethaderu 3:78f223d34f36 115 };
ethaderu 3:78f223d34f36 116
ethaderu 3:78f223d34f36 117 } // namespace mbed
ethaderu 3:78f223d34f36 118
ethaderu 3:78f223d34f36 119 #endif