1 files changed, 73 insertions, 0 deletions
diff --git a/src/include/Distribution.h b/src/include/Distribution.h
new file mode 100644
index 000000000..56e998757
--- /dev/null
+++ b/src/include/Distribution.h
@@ -0,0 +1,73 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*- 
+// vim: ts=8 sw=2 smarttab
+/*
+ * Ceph - scalable distributed file system
+ *
+ * Copyright (C) 2004-2006 Sage Weil <sage@newdream.net>
+ *
+ * This is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License version 2.1, as published by the Free Software 
+ * Foundation.  See file COPYING.
+ * 
+ */
+
+
+#ifndef CEPH_DISTRIBUTION_H
+#define CEPH_DISTRIBUTION_H
+
+#include <vector>
+
+class Distribution {
+  std::vector<float> p;
+  std::vector<int> v;
+
+ public:
+  //Distribution() { 
+  //}
+  
+  unsigned get_width() {
+    return p.size();
+  }
+
+  void clear() {
+    p.clear();
+    v.clear();
+  }
+  void add(int val, float pr) {
+    p.push_back(pr);
+    v.push_back(val);
+  }
+
+  void random() {
+    float sum = 0.0;
+    for (unsigned i=0; i<p.size(); i++) {
+      p[i] = (float)(rand() % 10000);
+      sum += p[i];
+    }
+    for (unsigned i=0; i<p.size(); i++) 
+      p[i] /= sum;
+  }
+
+  int sample() {
+    float s = (float)(rand() % 10000) / 10000.0;
+    for (unsigned i=0; i<p.size(); i++) {
+      if (s < p[i]) return v[i];
+      s -= p[i];
+    }
+    ceph_abort();
+    return v[p.size() - 1];  // hmm.  :/
+  }
+
+  float normalize() {
+    float s = 0.0;
+    for (unsigned i=0; i<p.size(); i++)
+      s += p[i];
+    for (unsigned i=0; i<p.size(); i++)
+      p[i] /= s;
+    return s;
+  }
+
+};
+
+#endif