michael@0: /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
michael@0: /* vim: set ts=2 et sw=2 tw=80: */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
michael@0:  * You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: /* Original author: bcampen@mozilla.com */
michael@0: 
michael@0: /*
michael@0:  *  This file defines a dirt-simple token bucket class.
michael@0:  */
michael@0: 
michael@0: #ifndef simpletokenbucket_h__
michael@0: #define simpletokenbucket_h__
michael@0: 
michael@0: #include <stdint.h>
michael@0: 
michael@0: #include "prinrval.h"
michael@0: 
michael@0: #include "m_cpp_utils.h"
michael@0: 
michael@0: namespace mozilla {
michael@0: 
michael@0: class SimpleTokenBucket {
michael@0:   public:
michael@0:     /*
michael@0:      *  Create a SimpleTokenBucket with a given maximum size and
michael@0:      *  token replenishment rate.
michael@0:      *  (eg; if you want a maximum rate of 5 per second over a 7 second
michael@0:      *  period, call SimpleTokenBucket b(5*7, 5);)
michael@0:      */
michael@0:     SimpleTokenBucket(size_t bucket_size, size_t tokens_per_second);
michael@0: 
michael@0:     /*
michael@0:      *  Attempt to acquire a number of tokens. If successful, returns
michael@0:      *  |num_tokens|, otherwise returns the number of tokens currently
michael@0:      *  in the bucket.
michael@0:      *  Note: To get the number of tokens in the bucket, pass something
michael@0:      *  like UINT32_MAX.
michael@0:      */
michael@0:     size_t getTokens(size_t num_tokens);
michael@0: 
michael@0:   protected: // Allow testing to touch these.
michael@0:     uint64_t max_tokens_;
michael@0:     uint64_t num_tokens_;
michael@0:     size_t tokens_per_second_;
michael@0:     PRIntervalTime last_time_tokens_added_;
michael@0: 
michael@0:     DISALLOW_COPY_ASSIGN(SimpleTokenBucket);
michael@0: };
michael@0: } // namespace mozilla
michael@0: 
michael@0: #endif // simpletokenbucket_h__
michael@0: