From 5f8de423f190bbb79a62f804151bc24824fa32d8 Mon Sep 17 00:00:00 2001 From: "Matt A. Tobin" Date: Fri, 2 Feb 2018 04:16:08 -0500 Subject: Add m-esr52 at 52.6.0 --- media/mtransport/simpletokenbucket.cpp | 62 ++++++++++++++++++++++++++++++++++ 1 file changed, 62 insertions(+) create mode 100644 media/mtransport/simpletokenbucket.cpp (limited to 'media/mtransport/simpletokenbucket.cpp') diff --git a/media/mtransport/simpletokenbucket.cpp b/media/mtransport/simpletokenbucket.cpp new file mode 100644 index 000000000..6145a2bbf --- /dev/null +++ b/media/mtransport/simpletokenbucket.cpp @@ -0,0 +1,62 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* vim: set ts=2 et sw=2 tw=80: */ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this file, + * You can obtain one at http://mozilla.org/MPL/2.0/. */ + +/* Original author: bcampen@mozilla.com */ + +#include "simpletokenbucket.h" + +#include + +#include "prinrval.h" + +namespace mozilla { + +SimpleTokenBucket::SimpleTokenBucket(size_t bucket_size, + size_t tokens_per_second) : + max_tokens_(bucket_size), + num_tokens_(bucket_size), + tokens_per_second_(tokens_per_second), + last_time_tokens_added_(PR_IntervalNow()) { +} + +size_t SimpleTokenBucket::getTokens(size_t num_requested_tokens) { + // Only fill if there isn't enough to satisfy the request. + // If we get tokens so seldomly that we are able to roll the timer all + // the way around its range, then we lose that entire range of time + // for token accumulation. Probably not the end of the world. + if (num_requested_tokens > num_tokens_) { + PRIntervalTime now = PR_IntervalNow(); + + // If we roll over the max, since everything in this calculation is the same + // unsigned type, this will still yield the elapsed time (unless we've + // wrapped more than once). + PRIntervalTime elapsed_ticks = now - last_time_tokens_added_; + + uint32_t elapsed_milli_sec = PR_IntervalToMilliseconds(elapsed_ticks); + size_t tokens_to_add = (elapsed_milli_sec * tokens_per_second_)/1000; + + // Only update our timestamp if we added some tokens + // TODO:(bcampen@mozilla.com) Should we attempt to "save" leftover time? + if (tokens_to_add) { + num_tokens_ += tokens_to_add; + if (num_tokens_ > max_tokens_) { + num_tokens_ = max_tokens_; + } + + last_time_tokens_added_ = now; + } + + if (num_requested_tokens > num_tokens_) { + return num_tokens_; + } + } + + num_tokens_ -= num_requested_tokens; + return num_requested_tokens; +} + +} // namespace mozilla + -- cgit v1.2.3