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Opencv 3.1 project on GR-PEACH board

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platform/FileHandle.h@170:54ff26da7eb6, 2017-07-04 (annotated)

Committer:
thedo
Date:
Tue Jul 04 06:23:13 2017 +0000
Revision:
170:54ff26da7eb6
Parent:
166:3a9487d57a5c 
project opencv 3.1 on GR PEACH board, no use SD card.

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thedo 166:3a9487d57a5c 1 /* mbed Microcontroller Library
thedo 166:3a9487d57a5c 2 * Copyright (c) 2017 ARM Limited
thedo 166:3a9487d57a5c 3 *
thedo 166:3a9487d57a5c 4 * Licensed under the Apache License, Version 2.0 (the "License");
thedo 166:3a9487d57a5c 5 * you may not use this file except in compliance with the License.
thedo 166:3a9487d57a5c 6 * You may obtain a copy of the License at
thedo 166:3a9487d57a5c 7 *
thedo 166:3a9487d57a5c 8 * http://www.apache.org/licenses/LICENSE-2.0
thedo 166:3a9487d57a5c 9 *
thedo 166:3a9487d57a5c 10 * Unless required by applicable law or agreed to in writing, software
thedo 166:3a9487d57a5c 11 * distributed under the License is distributed on an "AS IS" BASIS,
thedo 166:3a9487d57a5c 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
thedo 166:3a9487d57a5c 13 * See the License for the specific language governing permissions and
thedo 166:3a9487d57a5c 14 * limitations under the License.
thedo 166:3a9487d57a5c 15 */
thedo 166:3a9487d57a5c 16 #ifndef MBED_FILEHANDLE_H
thedo 166:3a9487d57a5c 17 #define MBED_FILEHANDLE_H
thedo 166:3a9487d57a5c 18
thedo 166:3a9487d57a5c 19 typedef int FILEHANDLE;
thedo 166:3a9487d57a5c 20
thedo 166:3a9487d57a5c 21 #include <cstdio>
thedo 166:3a9487d57a5c 22 #include "Callback.h"
thedo 166:3a9487d57a5c 23 #include "platform/mbed_poll.h"
thedo 166:3a9487d57a5c 24 #include "platform/platform.h"
thedo 166:3a9487d57a5c 25
thedo 166:3a9487d57a5c 26 namespace mbed {
thedo 166:3a9487d57a5c 27 /** \addtogroup platform */
thedo 166:3a9487d57a5c 28
thedo 166:3a9487d57a5c 29
thedo 166:3a9487d57a5c 30 /** Class FileHandle
thedo 166:3a9487d57a5c 31 *
thedo 166:3a9487d57a5c 32 * An abstract interface that represents operations on a file-like
thedo 166:3a9487d57a5c 33 * object. The core functions are read, write, and seek, but only
thedo 166:3a9487d57a5c 34 * a subset of these operations can be provided.
thedo 166:3a9487d57a5c 35 *
thedo 166:3a9487d57a5c 36 * @note to create a file, @see File
thedo 166:3a9487d57a5c 37 * @note Synchronization level: Set by subclass
thedo 166:3a9487d57a5c 38 * @ingroup platform
thedo 166:3a9487d57a5c 39 */
thedo 166:3a9487d57a5c 40 class FileHandle {
thedo 166:3a9487d57a5c 41 public:
thedo 166:3a9487d57a5c 42 virtual ~FileHandle() {}
thedo 166:3a9487d57a5c 43
thedo 166:3a9487d57a5c 44 /** Read the contents of a file into a buffer
thedo 166:3a9487d57a5c 45 *
thedo 166:3a9487d57a5c 46 * Devices acting as FileHandles should follow POSIX semantics:
thedo 166:3a9487d57a5c 47 *
thedo 166:3a9487d57a5c 48 * * if no data is available, and non-blocking set return -EAGAIN
thedo 166:3a9487d57a5c 49 * * if no data is available, and blocking set, wait until data is available
thedo 166:3a9487d57a5c 50 * * If any data is available, call returns immediately
thedo 166:3a9487d57a5c 51 *
thedo 166:3a9487d57a5c 52 * @param buffer The buffer to read in to
thedo 166:3a9487d57a5c 53 * @param size The number of bytes to read
thedo 166:3a9487d57a5c 54 * @return The number of bytes read, 0 at end of file, negative error on failure
thedo 166:3a9487d57a5c 55 */
thedo 166:3a9487d57a5c 56 virtual ssize_t read(void *buffer, size_t size) = 0;
thedo 166:3a9487d57a5c 57
thedo 166:3a9487d57a5c 58 /** Write the contents of a buffer to a file
thedo 166:3a9487d57a5c 59 *
thedo 166:3a9487d57a5c 60 * @param buffer The buffer to write from
thedo 166:3a9487d57a5c 61 * @param size The number of bytes to write
thedo 166:3a9487d57a5c 62 * @return The number of bytes written, negative error on failure
thedo 166:3a9487d57a5c 63 */
thedo 166:3a9487d57a5c 64 virtual ssize_t write(const void *buffer, size_t size) = 0;
thedo 166:3a9487d57a5c 65
thedo 166:3a9487d57a5c 66 /** Move the file position to a given offset from from a given location
thedo 166:3a9487d57a5c 67 *
thedo 166:3a9487d57a5c 68 * @param offset The offset from whence to move to
thedo 166:3a9487d57a5c 69 * @param whence The start of where to seek
thedo 166:3a9487d57a5c 70 * SEEK_SET to start from beginning of file,
thedo 166:3a9487d57a5c 71 * SEEK_CUR to start from current position in file,
thedo 166:3a9487d57a5c 72 * SEEK_END to start from end of file
thedo 166:3a9487d57a5c 73 * @return The new offset of the file, negative error code on failure
thedo 166:3a9487d57a5c 74 */
thedo 166:3a9487d57a5c 75 virtual off_t seek(off_t offset, int whence = SEEK_SET) = 0;
thedo 166:3a9487d57a5c 76
thedo 166:3a9487d57a5c 77 /** Close a file
thedo 166:3a9487d57a5c 78 *
thedo 166:3a9487d57a5c 79 * @return 0 on success, negative error code on failure
thedo 166:3a9487d57a5c 80 */
thedo 166:3a9487d57a5c 81 virtual int close() = 0;
thedo 166:3a9487d57a5c 82
thedo 166:3a9487d57a5c 83 /** Flush any buffers associated with the file
thedo 166:3a9487d57a5c 84 *
thedo 166:3a9487d57a5c 85 * @return 0 on success, negative error code on failure
thedo 166:3a9487d57a5c 86 */
thedo 166:3a9487d57a5c 87 virtual int sync()
thedo 166:3a9487d57a5c 88 {
thedo 166:3a9487d57a5c 89 return 0;
thedo 166:3a9487d57a5c 90 }
thedo 166:3a9487d57a5c 91
thedo 166:3a9487d57a5c 92 /** Check if the file in an interactive terminal device
thedo 166:3a9487d57a5c 93 *
thedo 166:3a9487d57a5c 94 * @return True if the file is a terminal
thedo 166:3a9487d57a5c 95 * @return False if the file is not a terminal
thedo 166:3a9487d57a5c 96 * @return Negative error code on failure
thedo 166:3a9487d57a5c 97 */
thedo 166:3a9487d57a5c 98 virtual int isatty()
thedo 166:3a9487d57a5c 99 {
thedo 166:3a9487d57a5c 100 return false;
thedo 166:3a9487d57a5c 101 }
thedo 166:3a9487d57a5c 102
thedo 166:3a9487d57a5c 103 /** Get the file position of the file
thedo 166:3a9487d57a5c 104 *
thedo 166:3a9487d57a5c 105 * @note This is equivalent to seek(0, SEEK_CUR)
thedo 166:3a9487d57a5c 106 *
thedo 166:3a9487d57a5c 107 * @return The current offset in the file, negative error code on failure
thedo 166:3a9487d57a5c 108 */
thedo 166:3a9487d57a5c 109 virtual off_t tell()
thedo 166:3a9487d57a5c 110 {
thedo 166:3a9487d57a5c 111 return seek(0, SEEK_CUR);
thedo 166:3a9487d57a5c 112 }
thedo 166:3a9487d57a5c 113
thedo 166:3a9487d57a5c 114 /** Rewind the file position to the beginning of the file
thedo 166:3a9487d57a5c 115 *
thedo 166:3a9487d57a5c 116 * @note This is equivalent to seek(0, SEEK_SET)
thedo 166:3a9487d57a5c 117 */
thedo 166:3a9487d57a5c 118 virtual void rewind()
thedo 166:3a9487d57a5c 119 {
thedo 166:3a9487d57a5c 120 seek(0, SEEK_SET);
thedo 166:3a9487d57a5c 121 }
thedo 166:3a9487d57a5c 122
thedo 166:3a9487d57a5c 123 /** Get the size of the file
thedo 166:3a9487d57a5c 124 *
thedo 166:3a9487d57a5c 125 * @return Size of the file in bytes
thedo 166:3a9487d57a5c 126 */
thedo 166:3a9487d57a5c 127 virtual off_t size();
thedo 166:3a9487d57a5c 128
thedo 166:3a9487d57a5c 129 /** Move the file position to a given offset from a given location.
thedo 166:3a9487d57a5c 130 *
thedo 166:3a9487d57a5c 131 * @param offset The offset from whence to move to
thedo 166:3a9487d57a5c 132 * @param whence SEEK_SET for the start of the file, SEEK_CUR for the
thedo 166:3a9487d57a5c 133 * current file position, or SEEK_END for the end of the file.
thedo 166:3a9487d57a5c 134 *
thedo 166:3a9487d57a5c 135 * @returns
thedo 166:3a9487d57a5c 136 * new file position on success,
thedo 166:3a9487d57a5c 137 * -1 on failure or unsupported
thedo 166:3a9487d57a5c 138 */
thedo 166:3a9487d57a5c 139 MBED_DEPRECATED_SINCE("mbed-os-5.4", "Replaced by FileHandle::seek")
thedo 166:3a9487d57a5c 140 virtual off_t lseek(off_t offset, int whence)
thedo 166:3a9487d57a5c 141 {
thedo 166:3a9487d57a5c 142 return seek(offset, whence);
thedo 166:3a9487d57a5c 143 }
thedo 166:3a9487d57a5c 144
thedo 166:3a9487d57a5c 145 /** Flush any buffers associated with the FileHandle, ensuring it
thedo 166:3a9487d57a5c 146 * is up to date on disk
thedo 166:3a9487d57a5c 147 *
thedo 166:3a9487d57a5c 148 * @returns
thedo 166:3a9487d57a5c 149 * 0 on success or un-needed,
thedo 166:3a9487d57a5c 150 * -1 on error
thedo 166:3a9487d57a5c 151 */
thedo 166:3a9487d57a5c 152 MBED_DEPRECATED_SINCE("mbed-os-5.4", "Replaced by FileHandle::sync")
thedo 166:3a9487d57a5c 153 virtual int fsync()
thedo 166:3a9487d57a5c 154 {
thedo 166:3a9487d57a5c 155 return sync();
thedo 166:3a9487d57a5c 156 }
thedo 166:3a9487d57a5c 157
thedo 166:3a9487d57a5c 158 /** Find the length of the file
thedo 166:3a9487d57a5c 159 *
thedo 166:3a9487d57a5c 160 * @returns
thedo 166:3a9487d57a5c 161 * Length of the file
thedo 166:3a9487d57a5c 162 */
thedo 166:3a9487d57a5c 163 MBED_DEPRECATED_SINCE("mbed-os-5.4", "Replaced by FileHandle::size")
thedo 166:3a9487d57a5c 164 virtual off_t flen()
thedo 166:3a9487d57a5c 165 {
thedo 166:3a9487d57a5c 166 return size();
thedo 166:3a9487d57a5c 167 }
thedo 166:3a9487d57a5c 168
thedo 166:3a9487d57a5c 169 /** Set blocking or non-blocking mode of the file operation like read/write.
thedo 166:3a9487d57a5c 170 * Definition depends upon the subclass implementing FileHandle.
thedo 166:3a9487d57a5c 171 * The default is blocking.
thedo 166:3a9487d57a5c 172 *
thedo 166:3a9487d57a5c 173 * @param blocking true for blocking mode, false for non-blocking mode.
thedo 166:3a9487d57a5c 174 */
thedo 166:3a9487d57a5c 175 virtual int set_blocking(bool blocking)
thedo 166:3a9487d57a5c 176 {
thedo 166:3a9487d57a5c 177 return -1;
thedo 166:3a9487d57a5c 178 }
thedo 166:3a9487d57a5c 179
thedo 166:3a9487d57a5c 180 /** Check for poll event flags
thedo 166:3a9487d57a5c 181 * The input parameter can be used or ignored - the could always return all events,
thedo 166:3a9487d57a5c 182 * or could check just the events listed in events.
thedo 166:3a9487d57a5c 183 * Call is non-blocking - returns instantaneous state of events.
thedo 166:3a9487d57a5c 184 * Whenever an event occurs, the derived class should call the sigio() callback).
thedo 166:3a9487d57a5c 185 *
thedo 166:3a9487d57a5c 186 * @param events bitmask of poll events we're interested in - POLLIN/POLLOUT etc.
thedo 166:3a9487d57a5c 187 *
thedo 166:3a9487d57a5c 188 * @returns
thedo 166:3a9487d57a5c 189 * bitmask of poll events that have occurred.
thedo 166:3a9487d57a5c 190 */
thedo 166:3a9487d57a5c 191 virtual short poll(short events) const
thedo 166:3a9487d57a5c 192 {
thedo 166:3a9487d57a5c 193 // Possible default for real files
thedo 166:3a9487d57a5c 194 return POLLIN | POLLOUT;
thedo 166:3a9487d57a5c 195 }
thedo 166:3a9487d57a5c 196
thedo 166:3a9487d57a5c 197 /** Returns true if the FileHandle is writable.
thedo 166:3a9487d57a5c 198 * Definition depends upon the subclass implementing FileHandle.
thedo 166:3a9487d57a5c 199 * For example, if the FileHandle is of type Stream, writable() could return
thedo 166:3a9487d57a5c 200 * true when there is ample buffer space available for write() calls.
thedo 166:3a9487d57a5c 201 */
thedo 166:3a9487d57a5c 202 bool writable() const
thedo 166:3a9487d57a5c 203 {
thedo 166:3a9487d57a5c 204 return poll(POLLOUT) & POLLOUT;
thedo 166:3a9487d57a5c 205 }
thedo 166:3a9487d57a5c 206
thedo 166:3a9487d57a5c 207 /** Returns true if the FileHandle is readable.
thedo 166:3a9487d57a5c 208 * Definition depends upon the subclass implementing FileHandle.
thedo 166:3a9487d57a5c 209 * For example, if the FileHandle is of type Stream, readable() could return
thedo 166:3a9487d57a5c 210 * true when there is something available to read.
thedo 166:3a9487d57a5c 211 */
thedo 166:3a9487d57a5c 212 bool readable() const
thedo 166:3a9487d57a5c 213 {
thedo 166:3a9487d57a5c 214 return poll(POLLIN) & POLLIN;
thedo 166:3a9487d57a5c 215 }
thedo 166:3a9487d57a5c 216
thedo 166:3a9487d57a5c 217 /** Register a callback on state change of the file.
thedo 166:3a9487d57a5c 218 *
thedo 166:3a9487d57a5c 219 * The specified callback will be called on state changes such as when
thedo 166:3a9487d57a5c 220 * the file can be written to or read from.
thedo 166:3a9487d57a5c 221 *
thedo 166:3a9487d57a5c 222 * The callback may be called in an interrupt context and should not
thedo 166:3a9487d57a5c 223 * perform expensive operations.
thedo 166:3a9487d57a5c 224 *
thedo 166:3a9487d57a5c 225 * Note! This is not intended as an attach-like asynchronous api, but rather
thedo 166:3a9487d57a5c 226 * as a building block for constructing such functionality.
thedo 166:3a9487d57a5c 227 *
thedo 166:3a9487d57a5c 228 * The exact timing of when the registered function
thedo 166:3a9487d57a5c 229 * is called is not guaranteed and susceptible to change. It should be used
thedo 166:3a9487d57a5c 230 * as a cue to make read/write/poll calls to find the current state.
thedo 166:3a9487d57a5c 231 *
thedo 166:3a9487d57a5c 232 * @param func Function to call on state change
thedo 166:3a9487d57a5c 233 */
thedo 166:3a9487d57a5c 234 virtual void sigio(Callback<void()> func)
thedo 166:3a9487d57a5c 235 {
thedo 166:3a9487d57a5c 236 //Default for real files. Do nothing for real files.
thedo 166:3a9487d57a5c 237 }
thedo 166:3a9487d57a5c 238 };
thedo 166:3a9487d57a5c 239
thedo 166:3a9487d57a5c 240 /** Not a member function
thedo 166:3a9487d57a5c 241 * This call is equivalent to posix fdopen().
thedo 166:3a9487d57a5c 242 * Returns a pointer to std::FILE.
thedo 166:3a9487d57a5c 243 * It associates a Stream to an already opened file descriptor (FileHandle)
thedo 166:3a9487d57a5c 244 *
thedo 166:3a9487d57a5c 245 * @param fh a pointer to an opened file descriptor
thedo 166:3a9487d57a5c 246 * @param mode operation upon the file descriptor, e.g., 'wb+'*/
thedo 166:3a9487d57a5c 247
thedo 166:3a9487d57a5c 248 std::FILE *fdopen(FileHandle *fh, const char *mode);
thedo 166:3a9487d57a5c 249
thedo 166:3a9487d57a5c 250 } // namespace mbed
thedo 166:3a9487d57a5c 251
thedo 166:3a9487d57a5c 252 #endif
thedo 166:3a9487d57a5c 253