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authorNicolas Schodet2015-09-28 16:31:51 +0200
committerNicolas Schodet2019-10-07 00:44:50 +0200
commit70bdcfef7a72d30951f2be1c8bb30a7ee6ded007 (patch)
tree140ff3899ffcd707769bbe3fd8a677e46b46520a /ucoo/utils/rate_limit.hh
parent3f3e2aeac4128545cb921171296fbd4b3e21b510 (diff)
ucoo/utils: add rate limit utility
Diffstat (limited to 'ucoo/utils/rate_limit.hh')
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1 files changed, 61 insertions, 0 deletions
diff --git a/ucoo/utils/rate_limit.hh b/ucoo/utils/rate_limit.hh
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+#ifndef ucoo_utils_rate_limit_hh
+#define ucoo_utils_rate_limit_hh
+// ucoolib - Microcontroller object oriented library. {{{
+//
+// Copyright (C) 2015 Nicolas Schodet
+//
+// 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.
+//
+// }}}
+
+namespace ucoo {
+
+/// Rate limiting object, call it to ask for permission to issue an event.
+/// Care should be taken to ask for permission often enough to avoid timer
+/// overflow problems or to call refresh.
+template<typename Timer>
+class RateLimit
+{
+ public:
+ /// Constructor.
+ RateLimit (const Timer &timer);
+ /// Constructor. Set rate limit, in Hz. Timer frequency must be known
+ /// yet.
+ RateLimit (const Timer &timer, int rate_num, int rate_denum = 1);
+ /// Set rate limit, in Hz.
+ inline void set_limit (int rate_num, int rate_denum = 1);
+ /// Ask for permission, return true if allowed.
+ bool operator () ();
+ /// Refresh timestamp to avoid overflow, must be called periodically when
+ /// permission is not requested often enough.
+ void refresh ();
+ private:
+ /// Associated timer.
+ const Timer &timer_;
+ /// Minimum interval between events.
+ unsigned int interval_ = 0;
+ /// Next event timer value.
+ unsigned int next_ = 0;
+};
+
+} // namespace ucoo
+
+#include "ucoo/utils/rate_limit.tcc"
+
+#endif // ucoo_utils_rate_limit_hh