From 5bcc35612c2e636ca2e0bb9a7c3c875d3d63250a Mon Sep 17 00:00:00 2001
From: Danny Robson <danny@nerdcruft.net>
Date: Fri, 20 Sep 2013 17:33:08 +1000
Subject: [PATCH] Add period query class

---
 time.cpp | 18 ++++++++++++++++++
 time.hpp | 14 ++++++++++++++
 2 files changed, 32 insertions(+)

diff --git a/time.cpp b/time.cpp
index a96bfd3e..899659e7 100644
--- a/time.cpp
+++ b/time.cpp
@@ -92,6 +92,24 @@ delta_clock::seconds (void) {
     return (time.curr - time.prev) / static_cast<double> (SECOND);
 }
 
+// ----------------------------------------------------------------------------
+util::period_query::period_query (double seconds) {
+    m_time.start  = nanoseconds ();
+    m_time.period = seconds * SECOND;
+}
+
+
+bool
+util::period_query::poll (void) {
+    uint64_t now  = nanoseconds ();
+    uint64_t diff = now - m_time.start;
+    if (diff < m_time.period)
+        return false;
+
+    m_time.start += diff % m_time.period;
+    return true;
+}
+
 
 // ----------------------------------------------------------------------------
 util::rate_limiter::rate_limiter (unsigned rate):
diff --git a/time.hpp b/time.hpp
index 244d9a15..22105e18 100644
--- a/time.hpp
+++ b/time.hpp
@@ -43,6 +43,20 @@ namespace util {
             } time;
     };
 
+    // ------------------------------------------------------------------------
+    class period_query {
+        public:
+            period_query (double seconds);
+
+            bool poll (void);
+
+        protected:
+            struct {
+                uint64_t start;
+                uint64_t period;
+            } m_time;
+    };
+
     // ------------------------------------------------------------------------
     class rate_limiter {
         public: