From 16ba048f8fdf5e7d0d419c3427f002558d0a8c7d Mon Sep 17 00:00:00 2001
From: Julian Viereck <jviereck@tuebingen.mpg.de>
Date: Thu, 26 Nov 2020 17:54:34 +0100
Subject: [PATCH] Adding HardSpinner class

---
 CMakeLists.txt                           |  1 +
 include/real_time_tools/hard_spinner.hpp | 46 ++++++++++++++++++++++++
 include/real_time_tools/spinner.hpp      |  2 +-
 src/hard_spinner.cpp                     | 26 ++++++++++++++
 4 files changed, 74 insertions(+), 1 deletion(-)
 create mode 100644 include/real_time_tools/hard_spinner.hpp
 create mode 100644 src/hard_spinner.cpp

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 622b46c..f44bdb9 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -39,6 +39,7 @@ add_library(${LIBRARY_NAME}
   src/realtime_check.cpp
   src/thread.cpp
   src/spinner.cpp
+  src/hard_spinner.cpp
   src/timer.cpp
   src/iostream.cpp
   src/usb_stream.cpp
diff --git a/include/real_time_tools/hard_spinner.hpp b/include/real_time_tools/hard_spinner.hpp
new file mode 100644
index 0000000..7a525b7
--- /dev/null
+++ b/include/real_time_tools/hard_spinner.hpp
@@ -0,0 +1,46 @@
+/**
+ * @file hard_spinner.cpp
+ * @author Julian Viereck (jviereck@tuebingen.mpg.de)
+ * license License BSD-3-Clause
+ * @copyright Copyright (c) 2020, New York University and Max Planck
+ * Gesellschaft.
+ * @date 2020-11-26
+ *
+ * @brief This file implements a hard spinner to time a loop. Compared to the 
+ *   Spinner class, this spinner uses the desired frequency for how often to
+ *   spin instead of the desired waiting time.
+ * 
+ * \code{.txt}
+ *    Spinner:     |-----1 ms-----| |-work-| |-----1 ms-----| |-work-|
+ *    HardSpinner: |-|-work-|-----| |-|-work-|-----| |-|-work-|-----|
+ * \endcode
+ */
+
+#ifndef HARD_SPINNER_HPP
+#define HARD_SPINNER_HPP
+
+#include <unistd.h>
+#include <chrono>
+#include <real_time_tools/spinner.hpp>
+
+namespace real_time_tools
+{
+/**
+ * @brief Class to have threads / loops running at a desired frequency
+ */
+class HardSpinner: Spinner
+{
+public:
+    // create a spinner for the desired frequency
+    HardSpinner();
+
+    /**
+     * @brief spin waits for the time such that successive calls to spin
+     * will result in spin being called at the desired frequency.
+     */
+    void spin();
+};
+
+}  // namespace real_time_tools
+
+#endif  // SPINNER_HPP
diff --git a/include/real_time_tools/spinner.hpp b/include/real_time_tools/spinner.hpp
index 290af91..a0c4c40 100644
--- a/include/real_time_tools/spinner.hpp
+++ b/include/real_time_tools/spinner.hpp
@@ -62,7 +62,7 @@ class Spinner
      */
     double predict_sleeping_time();
 
-private:
+protected:
     /**
      * @brief period_sec_ is the period of the loop in seconds
      */
diff --git a/src/hard_spinner.cpp b/src/hard_spinner.cpp
new file mode 100644
index 0000000..dd67cff
--- /dev/null
+++ b/src/hard_spinner.cpp
@@ -0,0 +1,26 @@
+/**
+ * @file hard_spinner.cpp
+ * @author Julian Viereck (jviereck@tuebingen.mpg.de)
+ * license License BSD-3-Clause
+ * @copyright Copyright (c) 2020, New York University and Max Planck
+ * Gesellschaft.
+ * @date 2020-11-26
+ *
+ * @brief This file implements a hard spinner to time a loop.
+ */
+
+#include <real_time_tools/hard_spinner.hpp>
+#include <real_time_tools/timer.hpp>
+
+namespace real_time_tools
+{
+HardSpinner::HardSpinner()
+: Spinner() { }
+
+void HardSpinner::spin()
+{
+    Timer::sleep_until_sec(next_date_sec_);
+    next_date_sec_ = next_date_sec_ + period_sec_;
+}
+
+}  // namespace real_time_tools