lzbp li / mbed-stm32l0l1-src-1

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Fork of mbed-stm32l0/l1-src by lzbp li

api/FileHandle.h@638:56887a2974b9, 2016-09-08 (annotated)

Committer:
lzbpli
Date:
Thu Sep 08 02:46:37 2016 +0000
Revision:
638:56887a2974b9
Parent:
13:0645d8841f51 
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bogdanm 13:0645d8841f51 1 /* mbed Microcontroller Library
bogdanm 13:0645d8841f51 2 * Copyright (c) 2006-2013 ARM Limited
bogdanm 13:0645d8841f51 3 *
bogdanm 13:0645d8841f51 4 * Licensed under the Apache License, Version 2.0 (the "License");
bogdanm 13:0645d8841f51 5 * you may not use this file except in compliance with the License.
bogdanm 13:0645d8841f51 6 * You may obtain a copy of the License at
bogdanm 13:0645d8841f51 7 *
bogdanm 13:0645d8841f51 8 * http://www.apache.org/licenses/LICENSE-2.0
bogdanm 13:0645d8841f51 9 *
bogdanm 13:0645d8841f51 10 * Unless required by applicable law or agreed to in writing, software
bogdanm 13:0645d8841f51 11 * distributed under the License is distributed on an "AS IS" BASIS,
bogdanm 13:0645d8841f51 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
bogdanm 13:0645d8841f51 13 * See the License for the specific language governing permissions and
bogdanm 13:0645d8841f51 14 * limitations under the License.
bogdanm 13:0645d8841f51 15 */
bogdanm 13:0645d8841f51 16 #ifndef MBED_FILEHANDLE_H
bogdanm 13:0645d8841f51 17 #define MBED_FILEHANDLE_H
bogdanm 13:0645d8841f51 18
bogdanm 13:0645d8841f51 19 typedef int FILEHANDLE;
bogdanm 13:0645d8841f51 20
bogdanm 13:0645d8841f51 21 #include <stdio.h>
bogdanm 13:0645d8841f51 22
bogdanm 13:0645d8841f51 23 #if defined(__ARMCC_VERSION) || defined(__ICCARM__)
bogdanm 13:0645d8841f51 24 typedef int ssize_t;
bogdanm 13:0645d8841f51 25 typedef long off_t;
bogdanm 13:0645d8841f51 26
bogdanm 13:0645d8841f51 27 #else
bogdanm 13:0645d8841f51 28 # include <sys/types.h>
bogdanm 13:0645d8841f51 29 #endif
bogdanm 13:0645d8841f51 30
bogdanm 13:0645d8841f51 31 namespace mbed {
bogdanm 13:0645d8841f51 32
bogdanm 13:0645d8841f51 33 /** An OO equivalent of the internal FILEHANDLE variable
bogdanm 13:0645d8841f51 34 * and associated _sys_* functions.
bogdanm 13:0645d8841f51 35 *
bogdanm 13:0645d8841f51 36 * FileHandle is an abstract class, needing at least sys_write and
bogdanm 13:0645d8841f51 37 * sys_read to be implmented for a simple interactive device.
bogdanm 13:0645d8841f51 38 *
bogdanm 13:0645d8841f51 39 * No one ever directly tals to/instanciates a FileHandle - it gets
bogdanm 13:0645d8841f51 40 * created by FileSystem, and wrapped up by stdio.
bogdanm 13:0645d8841f51 41 */
bogdanm 13:0645d8841f51 42 class FileHandle {
bogdanm 13:0645d8841f51 43
bogdanm 13:0645d8841f51 44 public:
bogdanm 13:0645d8841f51 45 /** Write the contents of a buffer to the file
bogdanm 13:0645d8841f51 46 *
bogdanm 13:0645d8841f51 47 * @param buffer the buffer to write from
bogdanm 13:0645d8841f51 48 * @param length the number of characters to write
bogdanm 13:0645d8841f51 49 *
bogdanm 13:0645d8841f51 50 * @returns
bogdanm 13:0645d8841f51 51 * The number of characters written (possibly 0) on success, -1 on error.
bogdanm 13:0645d8841f51 52 */
bogdanm 13:0645d8841f51 53 virtual ssize_t write(const void* buffer, size_t length) = 0;
bogdanm 13:0645d8841f51 54
bogdanm 13:0645d8841f51 55 /** Close the file
bogdanm 13:0645d8841f51 56 *
bogdanm 13:0645d8841f51 57 * @returns
bogdanm 13:0645d8841f51 58 * Zero on success, -1 on error.
bogdanm 13:0645d8841f51 59 */
bogdanm 13:0645d8841f51 60 virtual int close() = 0;
bogdanm 13:0645d8841f51 61
bogdanm 13:0645d8841f51 62 /** Function read
bogdanm 13:0645d8841f51 63 * Reads the contents of the file into a buffer
bogdanm 13:0645d8841f51 64 *
bogdanm 13:0645d8841f51 65 * @param buffer the buffer to read in to
bogdanm 13:0645d8841f51 66 * @param length the number of characters to read
bogdanm 13:0645d8841f51 67 *
bogdanm 13:0645d8841f51 68 * @returns
bogdanm 13:0645d8841f51 69 * The number of characters read (zero at end of file) on success, -1 on error.
bogdanm 13:0645d8841f51 70 */
bogdanm 13:0645d8841f51 71 virtual ssize_t read(void* buffer, size_t length) = 0;
bogdanm 13:0645d8841f51 72
bogdanm 13:0645d8841f51 73 /** Check if the handle is for a interactive terminal device.
bogdanm 13:0645d8841f51 74 * If so, line buffered behaviour is used by default
bogdanm 13:0645d8841f51 75 *
bogdanm 13:0645d8841f51 76 * @returns
bogdanm 13:0645d8841f51 77 * 1 if it is a terminal,
bogdanm 13:0645d8841f51 78 * 0 otherwise
bogdanm 13:0645d8841f51 79 */
bogdanm 13:0645d8841f51 80 virtual int isatty() = 0;
bogdanm 13:0645d8841f51 81
bogdanm 13:0645d8841f51 82 /** Move the file position to a given offset from a given location.
bogdanm 13:0645d8841f51 83 *
bogdanm 13:0645d8841f51 84 * @param offset The offset from whence to move to
bogdanm 13:0645d8841f51 85 * @param whence SEEK_SET for the start of the file, SEEK_CUR for the
bogdanm 13:0645d8841f51 86 * current file position, or SEEK_END for the end of the file.
bogdanm 13:0645d8841f51 87 *
bogdanm 13:0645d8841f51 88 * @returns
bogdanm 13:0645d8841f51 89 * new file position on success,
bogdanm 13:0645d8841f51 90 * -1 on failure or unsupported
bogdanm 13:0645d8841f51 91 */
bogdanm 13:0645d8841f51 92 virtual off_t lseek(off_t offset, int whence) = 0;
bogdanm 13:0645d8841f51 93
bogdanm 13:0645d8841f51 94 /** Flush any buffers associated with the FileHandle, ensuring it
bogdanm 13:0645d8841f51 95 * is up to date on disk
bogdanm 13:0645d8841f51 96 *
bogdanm 13:0645d8841f51 97 * @returns
bogdanm 13:0645d8841f51 98 * 0 on success or un-needed,
bogdanm 13:0645d8841f51 99 * -1 on error
bogdanm 13:0645d8841f51 100 */
bogdanm 13:0645d8841f51 101 virtual int fsync() = 0;
bogdanm 13:0645d8841f51 102
bogdanm 13:0645d8841f51 103 virtual off_t flen() {
bogdanm 13:0645d8841f51 104 /* remember our current position */
bogdanm 13:0645d8841f51 105 off_t pos = lseek(0, SEEK_CUR);
bogdanm 13:0645d8841f51 106 if(pos == -1) return -1;
bogdanm 13:0645d8841f51 107 /* seek to the end to get the file length */
bogdanm 13:0645d8841f51 108 off_t res = lseek(0, SEEK_END);
bogdanm 13:0645d8841f51 109 /* return to our old position */
bogdanm 13:0645d8841f51 110 lseek(pos, SEEK_SET);
bogdanm 13:0645d8841f51 111 return res;
bogdanm 13:0645d8841f51 112 }
bogdanm 13:0645d8841f51 113
bogdanm 13:0645d8841f51 114 virtual ~FileHandle();
bogdanm 13:0645d8841f51 115 };
bogdanm 13:0645d8841f51 116
bogdanm 13:0645d8841f51 117 } // namespace mbed
bogdanm 13:0645d8841f51 118
bogdanm 13:0645d8841f51 119 #endif