Diff: drivers/FileHandle.h

Revision:

149:156823d33999

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/drivers/FileHandle.h	Fri Oct 28 11:17:30 2016 +0100
@@ -0,0 +1,144 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2006-2013 ARM Limited
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#ifndef MBED_FILEHANDLE_H
+#define MBED_FILEHANDLE_H
+
+typedef int FILEHANDLE;
+
+#include <stdio.h>
+
+#if defined(__ARMCC_VERSION) || defined(__ICCARM__)
+typedef int ssize_t;
+typedef long off_t;
+
+#else
+#   include <sys/types.h>
+#endif
+
+namespace mbed {
+/** \addtogroup drivers */
+/** @{*/
+
+/** An OO equivalent of the internal FILEHANDLE variable
+ *  and associated _sys_* functions.
+ *
+ * FileHandle is an abstract class, needing at least sys_write and
+ *  sys_read to be implmented for a simple interactive device.
+ *
+ * No one ever directly tals to/instanciates a FileHandle - it gets
+ *  created by FileSystem, and wrapped up by stdio.
+ *
+ * @Note Synchronization level: Set by subclass
+ */
+class FileHandle {
+
+public:
+    /** Write the contents of a buffer to the file
+     *
+     *  @param buffer the buffer to write from
+     *  @param length the number of characters to write
+     *
+     *  @returns
+     *  The number of characters written (possibly 0) on success, -1 on error.
+     */
+    virtual ssize_t write(const void* buffer, size_t length) = 0;
+
+    /** Close the file
+     *
+     *  @returns
+     *  Zero on success, -1 on error.
+     */
+    virtual int close() = 0;
+
+    /** Function read
+     *  Reads the contents of the file into a buffer
+     *
+     *  @param buffer the buffer to read in to
+     *  @param length the number of characters to read
+     *
+     *  @returns
+     *  The number of characters read (zero at end of file) on success, -1 on error.
+     */
+    virtual ssize_t read(void* buffer, size_t length) = 0;
+
+    /** Check if the handle is for a interactive terminal device.
+     * If so, line buffered behaviour is used by default
+     *
+     *  @returns
+     *    1 if it is a terminal,
+     *    0 otherwise
+     */
+    virtual int isatty() = 0;
+
+    /** Move the file position to a given offset from a given location.
+     *
+     *  @param offset The offset from whence to move to
+     *  @param whence SEEK_SET for the start of the file, SEEK_CUR for the
+     *   current file position, or SEEK_END for the end of the file.
+     *
+     *  @returns
+     *    new file position on success,
+     *    -1 on failure or unsupported
+     */
+    virtual off_t lseek(off_t offset, int whence) = 0;
+
+    /** Flush any buffers associated with the FileHandle, ensuring it
+     *  is up to date on disk
+     *
+     *  @returns
+     *    0 on success or un-needed,
+     *   -1 on error
+     */
+    virtual int fsync() = 0;
+
+    virtual off_t flen() {
+        lock();
+        /* remember our current position */
+        off_t pos = lseek(0, SEEK_CUR);
+        if(pos == -1) {
+            unlock();
+            return -1;
+        }
+        /* seek to the end to get the file length */
+        off_t res = lseek(0, SEEK_END);
+        /* return to our old position */
+        lseek(pos, SEEK_SET);
+        unlock();
+        return res;
+    }
+
+    virtual ~FileHandle();
+
+protected:
+
+    /** Acquire exclusive access to this object.
+     */
+    virtual void lock() {
+        // Stub
+    }
+
+    /** Release exclusive access to this object.
+     */
+    virtual void unlock() {
+        // Stub
+    }
+};
+
+} // namespace mbed
+
+#endif
+
+/** @}*/