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+// -*- 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