Diff: AbstractDataSource.h

Revision:

0:099f76422485

Child:

11:e1bee9a77652

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/AbstractDataSource.h	Thu Jul 03 20:38:04 2014 +0200
@@ -0,0 +1,101 @@
+/*
+ * AbstractDataSource.h
+ *
+ * Created on: Nov 1, 2013
+ * * Authors: Vincent Wochnik <v.wochnik@gmail.com>
+ *
+ * Copyright (c) 2013 Cumulocity GmbH
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+/**
+ * @file AbstractDataSource.h
+ * An abstraction layer which provides means to read data from a
+ * connection.
+ * 
+ * Example:
+ * @code
+ * AbstractDataSource source;
+ * char c;
+ * while (((c = source.read()) > 0) || (source.status() == DS_STATUS_OK)) {
+ *     // read action
+ * }
+ * switch (source.status()) {
+ * case DS_STATUS_OK:
+ *     // ok
+ * case DS_STATUS_CLOSED:
+ *     // connection closed
+ * case DS_STATUS_TIMEOUT:
+ *     // timeout
+ * default:
+ *     // other error
+ * }
+ * @encode
+ * 
+ */
+
+#ifndef ABSTRACTDATASOURCE_H
+#define ABSTRACTDATASOURCE_H
+
+#include "config.h"
+#include <stdint.h>
+
+/** Return value indicating that no error has occurred. */
+#define DS_STATUS_OK 0
+/** Return value indicating that the connection has been closed by this
+ * or the foreign host. */
+#define DS_STATUS_CLOSED 1
+/** Return value indicating a transmission timeout. */
+#define DS_STATUS_TIMEOUT 2
+/** Return value indicating a state error. */
+#define DS_STATUS_ERROR 3
+
+/*
+ * The AbstractDataSource class provides a way to read data from a
+ * connection.
+ */
+class AbstractDataSource
+{
+public:
+    virtual ~AbstractDataSource() { };
+
+    /**
+     * Reads one character. When successful, the returned value
+     * represents the character. Otherwise, status() will return a
+     * non-zero value. This function is blocking.
+     * @return the caracter read or zero. If the return value is
+     * non-zero, status() is zero. Otherwise, check status() for a
+     * non-zero value.
+     */
+    virtual char read() = 0;
+
+    /**
+     * Returns the current read state. If a non-zero value is returned,
+     * there is an error. Otherwise, everything is ok.
+     * DS_STATUS_TIMEOUT means that there has been a read timeout.
+     * DS_STATUS_CLOSED means that the connection has been closed
+     * by either this or the foreign host.
+     * @return the status value
+     */
+    virtual uint8_t status() = 0;
+};
+
+#endif