From b4150d2053b1da20398746f41baaa63726c7951f Mon Sep 17 00:00:00 2001
From: Steffen Vogel <post@steffenvogel.de>
Date: Fri, 12 Apr 2019 09:50:42 +0200
Subject: [PATCH] hooks: add a common base class for rate limiting hooks

---
 include/villas/hook.hpp             |  9 +++++++++
 include/villas/hooks/decimate.hpp   | 15 +++++++++++++--
 include/villas/hooks/limit_rate.hpp | 14 +++++++-------
 3 files changed, 29 insertions(+), 9 deletions(-)

diff --git a/include/villas/hook.hpp b/include/villas/hook.hpp
index dcf78702b..253b8784c 100644
--- a/include/villas/hook.hpp
+++ b/include/villas/hook.hpp
@@ -140,6 +140,15 @@ public:
 	}
 };
 
+class LimitHook : public Hook {
+
+public:
+	using Hook::Hook;
+
+	virtual void setRate(double rate, double maxRate = -1) = 0;
+
+};
+
 class HookFactory : public plugin::Plugin {
 
 protected:
diff --git a/include/villas/hooks/decimate.hpp b/include/villas/hooks/decimate.hpp
index ec0cdf283..72261bb44 100644
--- a/include/villas/hooks/decimate.hpp
+++ b/include/villas/hooks/decimate.hpp
@@ -31,14 +31,25 @@
 namespace villas {
 namespace node {
 
-class DecimateHook : public Hook {
+class DecimateHook : public LimitHook {
 
 protected:
 	int ratio;
 	unsigned counter;
 
 public:
-	using Hook::Hook;
+	using LimitHook::LimitHook;
+
+	virtual void setRate(double rate, double maxRate = -1)
+	{
+		assert(maxRate > 0);
+
+		int ratio = maxRate / rate;
+		if (ratio == 0)
+			ratio = 1;
+
+		setRatio(ratio);
+	}
 
 	void setRatio(int r)
 	{
diff --git a/include/villas/hooks/limit_rate.hpp b/include/villas/hooks/limit_rate.hpp
index 2bed1f91a..26114b635 100644
--- a/include/villas/hooks/limit_rate.hpp
+++ b/include/villas/hooks/limit_rate.hpp
@@ -31,7 +31,7 @@
 namespace villas {
 namespace node {
 
-class LimitRateHook : public Hook {
+class LimitRateHook : public LimitHook {
 
 protected:
 	enum {
@@ -44,18 +44,18 @@ protected:
 	timespec last;
 
 public:
-	void setRate(double rate)
-	{
-		deadtime = 1.0 / rate;
-	}
-
 	LimitRateHook(struct path *p, struct node *n, int fl, int prio, bool en = true) :
-		Hook(p, n, fl, prio, en),
+		LimitHook(p, n, fl, prio, en),
 		mode(LIMIT_RATE_LOCAL)
 	{
 		last = (timespec) { 0, 0 };
 	}
 
+	virtual void setRate(double rate, double maxRate = -1)
+	{
+		deadtime = 1.0 / rate;
+	}
+
 	virtual void parse(json_t *cfg);
 
 	virtual int process(sample *smp);