1 files changed, 44 insertions, 0 deletions

diff --git a/sim/sim.h b/sim/sim.h
new file mode 100644
index 0000000..399832a
--- /dev/null
+++ b/sim/sim.h
@@ -0,0 +1,44 @@
+#pragma once
+
+#include <cstdint>
+#include <map>
+#include <set>
+#include <vector>
+
+namespace sim {
+
+    struct Schedulable;
+
+    struct Scheduler {
+        std::set<Schedulable *> unsorted_schedulables;
+        std::vector<Schedulable *> sorted_schedulables;
+        bool sort_needed = false;
+
+        std::multimap<Schedulable *, Schedulable *> constraints;
+
+        Schedulable *current_schedulable = nullptr;
+        std::uint64_t now = 0;
+
+        void add_schedulable(Schedulable *schedulable);
+        void remove_schedulable(Schedulable *schedulable);
+
+        void constrain(Schedulable *prior, Schedulable *later);
+
+        void topo_sort(std::set<Schedulable *> &live, std::set<Schedulable *> &waiting, Schedulable *candidate);
+        void sort();
+
+        void clock();
+    };
+
+    struct Schedulable {
+        Scheduler &scheduler;
+
+        Schedulable(Scheduler &scheduler);
+        virtual ~Schedulable();
+
+        virtual void clock() = 0;
+
+        std::uint64_t now();
+    };
+
+}