1 /* 2 * libjingle 3 * Copyright 2012, Google Inc. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright notice, 9 * this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright notice, 11 * this list of conditions and the following disclaimer in the documentation 12 * and/or other materials provided with the distribution. 13 * 3. The name of the author may not be used to endorse or promote products 14 * derived from this software without specific prior written permission. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 17 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 18 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO 19 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 20 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 21 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 22 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 23 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 24 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 25 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 */ 27 28 #ifndef TALK_BASE_RATELIMITER_H_ 29 #define TALK_BASE_RATELIMITER_H_ 30 31 #include <stdlib.h> 32 #include "talk/base/basictypes.h" 33 34 namespace talk_base { 35 36 // Limits the rate of use to a certain maximum quantity per period of 37 // time. Use, for example, for simple bandwidth throttling. 38 // 39 // It's implemented like a diet plan: You have so many calories per 40 // day. If you hit the limit, you can't eat any more until the next 41 // day. 42 class RateLimiter { 43 public: 44 // For example, 100kb per second. 45 RateLimiter(size_t max, double period) 46 : max_per_period_(max), 47 period_length_(period), 48 used_in_period_(0), 49 period_start_(0.0), 50 period_end_(period) { 51 } 52 virtual ~RateLimiter() {} 53 54 // Returns true if if the desired quantity is available in the 55 // current period (< (max - used)). Once the given time passes the 56 // end of the period, used is set to zero and more use is available. 57 bool CanUse(size_t desired, double time); 58 // Increment the quantity used this period. If past the end of a 59 // period, a new period is started. 60 void Use(size_t used, double time); 61 62 size_t used_in_period() const { 63 return used_in_period_; 64 } 65 66 size_t max_per_period() const { 67 return max_per_period_; 68 } 69 70 private: 71 size_t max_per_period_; 72 double period_length_; 73 size_t used_in_period_; 74 double period_start_; 75 double period_end_; 76 }; 77 78 } // namespace talk_base 79 80 #endif // TALK_BASE_RATELIMITER_H_ 81
