initial implementation

include/xo/simulator/SourceTimestamp.hpp

@@ -0,0 +1,107 @@
+/* file SourceTimestamp.hpp
+ *
+ * author: Roland Conybeare, Sep 2022
+ */
+
+#pragma once
+
+#include "xo/reactor/ReactorSource.hpp"
+
+namespace xo {
+    namespace sim {
+        /* remember a timestamp for a simulation source;
+         * use to insert a source into simulation heap.
+         * don't want to use SimulationSource.t0,  so that we can
+         * promise heap invariants without reying on
+         * any behavior of SimulationSource.
+         *
+         * Note: Need to resolve ties between different sources,
+         *       if they coincide on timestamp of next event.
+         *       For now use SimulationSource address
+         */
+        class SourceTimestamp {
+        public:
+            using ReactorSource = xo::reactor::ReactorSource;
+            using utc_nanos = xo::time::utc_nanos;
+
+        public:
+            SourceTimestamp(utc_nanos t0,
+                            ReactorSource * src)
+                : t0_(t0), src_(src) {}
+
+            static int32_t compare(SourceTimestamp const & x,
+                                   SourceTimestamp const & y) {
+                using xo::time::utc_nanos;
+                using xo::time::nanos;
+
+                nanos dt = x.t0_ - y.t0_;
+
+                if(dt < nanos(0))
+                    return -1;
+                else if(dt > nanos(0))
+                    return +1;
+
+                /* timestamps are equal */
+
+                std::ptrdiff_t dptr = (x.src() - y.src());
+
+                return dptr;
+            } /*compare*/
+
+            utc_nanos t0() const { return t0_; }
+            ReactorSource * src() const { return src_; }
+
+            void display(std::ostream & os) const;
+            std::string display_string() const;
+
+        private:
+            /* timestamp for this source */
+            utc_nanos t0_;
+            /* simulation source
+             * promise:
+             * - src.t0() >= .t0 || src.is_exhausted
+             */
+            ReactorSource * src_ = nullptr;
+        }; /*SourceTimestamp*/
+
+        inline bool operator==(SourceTimestamp const & x,
+                               SourceTimestamp const & y)
+        {
+            return SourceTimestamp::compare(x, y) == 0;
+        } /*operator==*/
+
+        inline bool operator<(SourceTimestamp const & x,
+                              SourceTimestamp const & y)
+        {
+            return SourceTimestamp::compare(x, y) < 0;
+        } /*operator<*/
+
+        inline bool operator<=(SourceTimestamp const & x,
+                               SourceTimestamp const & y)
+        {
+            return SourceTimestamp::compare(x, y) <= 0;
+        } /*operator<=*/
+
+        inline bool operator>(SourceTimestamp const & x,
+                              SourceTimestamp const & y)
+        {
+            return SourceTimestamp::compare(x, y) > 0;
+        } /*operator>*/
+
+        inline bool operator>=(SourceTimestamp const & x,
+                               SourceTimestamp const & y)
+        {
+            return SourceTimestamp::compare(x, y) >= 0;
+        } /*operator>=*/
+
+        inline std::ostream &
+        operator<<(std::ostream & os,
+                   SourceTimestamp const & x)
+        {
+            x.display(os);
+            return os;
+        } /*operator<<*/
+    } /*namespace sim*/
+} /*namespace xo*/
+
+/* end SourceTimestamp.hpp*/