o add bsnes

bsnes/lib/nall/priorityqueue.hpp

@@ -0,0 +1,94 @@
+#ifndef NALL_PRIORITYQUEUE_HPP
+#define NALL_PRIORITYQUEUE_HPP
+
+#include <limits>
+#include <nall/function.hpp>
+#include <nall/utility.hpp>
+
+namespace nall {
+  template<typename type_t> void priority_queue_nocallback(type_t) {}
+
+  //priority queue implementation using binary min-heap array;
+  //does not require normalize() function.
+  //O(1)     find   (tick)
+  //O(log n) insert (enqueue)
+  //O(log n) remove (dequeue)
+  template<typename type_t> class priority_queue : noncopyable {
+  public:
+    inline void tick(unsigned ticks) {
+      basecounter += ticks;
+      while(heapsize && gte(basecounter, heap[0].counter)) callback(dequeue());
+    }
+
+    //counter is relative to current time (eg enqueue(64, ...) fires in 64 ticks);
+    //counter cannot exceed std::numeric_limits<unsigned>::max() >> 1.
+    void enqueue(unsigned counter, type_t event) {
+      unsigned child = heapsize++;
+      counter += basecounter;
+
+      while(child) {
+        unsigned parent = (child - 1) >> 1;
+        if(gte(counter, heap[parent].counter)) break;
+
+        heap[child].counter = heap[parent].counter;
+        heap[child].event = heap[parent].event;
+        child = parent;
+      }
+
+      heap[child].counter = counter;
+      heap[child].event = event;
+    }
+
+    type_t dequeue() {
+      type_t event(heap[0].event);
+      unsigned parent = 0;
+      unsigned counter = heap[--heapsize].counter;
+
+      while(true) {
+        unsigned child = (parent << 1) + 1;
+        if(child >= heapsize) break;
+        if(child + 1 < heapsize && gte(heap[child].counter, heap[child + 1].counter)) child++;
+        if(gte(heap[child].counter, counter)) break;
+
+        heap[parent].counter = heap[child].counter;
+        heap[parent].event = heap[child].event;
+        parent = child;
+      }
+
+      heap[parent].counter = counter;
+      heap[parent].event = heap[heapsize].event;
+      return event;
+    }
+
+    void reset() {
+      basecounter = 0;
+      heapsize = 0;
+    }
+
+    priority_queue(unsigned size, function<void (type_t)> callback_ = &priority_queue_nocallback<type_t>)
+    : callback(callback_) {
+      heap = new heap_t[size];
+      reset();
+    }
+
+    ~priority_queue() {
+      delete[] heap;
+    }
+
+  private:
+    function<void (type_t)> callback;
+    unsigned basecounter;
+    unsigned heapsize;
+    struct heap_t {
+      unsigned counter;
+      type_t event;
+    } *heap;
+
+    //return true if x is greater than or equal to y
+    inline bool gte(unsigned x, unsigned y) {
+      return x - y < (std::numeric_limits<unsigned>::max() >> 1);
+    }
+  };
+}
+
+#endif