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diff --git a/attic/BandwidthAccount.hpp b/attic/BandwidthAccount.hpp
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+/*
+ * ZeroTier One - Network Virtualization Everywhere
+ * Copyright (C) 2011-2015  ZeroTier, Inc.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * --
+ *
+ * ZeroTier may be used and distributed under the terms of the GPLv3, which
+ * are available at: http://www.gnu.org/licenses/gpl-3.0.html
+ *
+ * If you would like to embed ZeroTier into a commercial application or
+ * redistribute it in a modified binary form, please contact ZeroTier Networks
+ * LLC. Start here: http://www.zerotier.com/
+ */
+
+#ifndef ZT_BWACCOUNT_HPP
+#define ZT_BWACCOUNT_HPP
+
+#include "Constants.hpp"
+
+#include <algorithm>
+
+#include <stdint.h>
+#include <math.h>
+
+#include "Utils.hpp"
+
+#ifdef __WINDOWS__
+#define	round(x) ((x-floor(x))>0.5 ? ceil(x) : floor(x))
+#endif
+
+namespace ZeroTier {
+
+/**
+ * Bandwidth account used for rate limiting multicast groups
+ *
+ * This is used to apply a bank account model to multicast groups. Each
+ * multicast packet counts against a balance, which accrues at a given
+ * rate in bytes per second. Debt is possible. These parameters are
+ * configurable.
+ *
+ * A bank account model permits bursting behavior, which correctly models
+ * how OSes and apps typically use multicast. It's common for things to
+ * spew lots of multicast messages at once, wait a while, then do it
+ * again. A consistent bandwidth limit model doesn't fit.
+ */
+class BandwidthAccount
+{
+public:
+	/**
+	 * Create an uninitialized account
+	 *
+	 * init() must be called before this is used.
+	 */
+	BandwidthAccount() throw() {}
+
+	/**
+	 * Create and initialize
+	 *
+	 * @param preload Initial balance to place in account
+	 * @param maxb Maximum allowed balance (> 0)
+	 * @param acc Rate of accrual in bytes per second
+	 * @param now Current time
+	 */
+	BandwidthAccount(uint32_t preload,uint32_t maxb,uint32_t acc,uint64_t now)
+		throw()
+	{
+		init(preload,maxb,acc,now);
+	}
+
+	/**
+	 * Initialize or re-initialize account
+	 *
+	 * @param preload Initial balance to place in account
+	 * @param maxb Maximum allowed balance (> 0)
+	 * @param acc Rate of accrual in bytes per second
+	 * @param now Current time
+	 */
+	inline void init(uint32_t preload,uint32_t maxb,uint32_t acc,uint64_t now)
+		throw()
+	{
+		_lastTime = ((double)now / 1000.0);
+		_balance = preload;
+		_maxBalance = maxb;
+		_accrual = acc;
+	}
+
+	/**
+	 * Update and retrieve balance of this account
+	 *
+	 * @param now Current time
+	 * @return New balance updated from current clock
+	 */
+	inline uint32_t update(uint64_t now)
+		throw()
+	{
+		double lt = _lastTime;
+		double nowf = ((double)now / 1000.0);
+		_lastTime = nowf;
+		return (_balance = std::min(_maxBalance,(uint32_t)round((double)_balance + ((double)_accrual * (nowf - lt)))));
+	}
+
+	/**
+	 * Update balance and conditionally deduct
+	 *
+	 * If the deduction amount fits, it is deducted after update. Otherwise
+	 * balance is updated and false is returned.
+	 *
+	 * @param amt Amount to deduct
+	 * @param now Current time
+	 * @return True if amount fit within balance and was deducted
+	 */
+	inline bool deduct(uint32_t amt,uint64_t now)
+		throw()
+	{
+		if (update(now) >= amt) {
+			_balance -= amt;
+			return true;
+		}
+		return false;
+	}
+
+	/**
+	 * @return Most recent balance without update
+	 */
+	inline uint32_t balance() const
+		throw()
+	{
+		return _balance;
+	}
+
+private:
+	double _lastTime;
+	uint32_t _balance;
+	uint32_t _maxBalance;
+	uint32_t _accrual;
+};
+
+} // namespace ZeroTier
+
+#endif