Diff: FileHandle.h

Revision:

0:a8fa94490a0a

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/FileHandle.h	Sat Sep 22 10:32:07 2012 +0000
@@ -0,0 +1,114 @@
+/* mbed Microcontroller Library - FileHandler
+ * Copyright (c) 2007-2009 ARM Limited. All rights reserved.
+ */ 
+ 
+#ifndef MBED_FILEHANDLE_H
+#define MBED_FILEHANDLE_H
+
+typedef int FILEHANDLE;
+
+#include <stdio.h>
+#ifdef __ARMCC_VERSION
+typedef int ssize_t;
+typedef long off_t;
+#else
+#include <sys/types.h>
+#endif
+
+namespace mbed { 
+
+/* Class FileHandle
+ *  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
+ */
+class FileHandle {
+
+public:
+
+    /* Function write
+     *  Write the contents of a buffer to the file
+     *
+     * Parameters
+     *  buffer - the buffer to write from
+     *  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;
+
+    /* Function close
+     *  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
+     *
+     * Parameters
+     *  buffer - the buffer to read in to
+     *  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;
+
+    /* Function isatty
+     *  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 ;
+
+    /* Function lseek
+     *  Move the file position to a given offset from a given location.
+     *
+     * Parameters
+     *  offset - The offset from whence to move to
+     *  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;
+
+    /* Function fsync
+     *  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() {
+        /* remember our current position */
+        off_t pos = lseek(0, SEEK_CUR);
+        if(pos == -1) 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);
+        return res;
+    }
+
+};
+
+} // namespace mbed
+
+#endif
+