Don Turner | ca6f91a | 2017-09-05 14:52:39 +0100 | [diff] [blame] | 1 | /* |
| 2 | * Copyright 2015 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
Phil Burk | 919cd42 | 2019-08-12 17:26:50 -0700 | [diff] [blame] | 17 | #include <algorithm> |
Phil Burk | 9446ed6 | 2020-07-13 11:26:55 -0700 | [diff] [blame] | 18 | #include <cassert> |
| 19 | #include <stdint.h> |
Don Turner | ca6f91a | 2017-09-05 14:52:39 +0100 | [diff] [blame] | 20 | |
Phil Burk | 9446ed6 | 2020-07-13 11:26:55 -0700 | [diff] [blame] | 21 | #include "FifoControllerBase.h" |
Don Turner | ca6f91a | 2017-09-05 14:52:39 +0100 | [diff] [blame] | 22 | |
Don Turner | 3bf32ae | 2017-11-27 13:25:05 +0000 | [diff] [blame] | 23 | namespace oboe { |
| 24 | |
Phil Burk | 919cd42 | 2019-08-12 17:26:50 -0700 | [diff] [blame] | 25 | FifoControllerBase::FifoControllerBase(uint32_t capacityInFrames) |
| 26 | : mTotalFrames(capacityInFrames) |
Don Turner | ca6f91a | 2017-09-05 14:52:39 +0100 | [diff] [blame] | 27 | { |
Phil Burk | 919cd42 | 2019-08-12 17:26:50 -0700 | [diff] [blame] | 28 | // Avoid ridiculously large buffers and the arithmetic wraparound issues that can follow. |
| 29 | assert(capacityInFrames <= (UINT32_MAX / 4)); |
Don Turner | ca6f91a | 2017-09-05 14:52:39 +0100 | [diff] [blame] | 30 | } |
| 31 | |
Phil Burk | 919cd42 | 2019-08-12 17:26:50 -0700 | [diff] [blame] | 32 | uint32_t FifoControllerBase::getFullFramesAvailable() const { |
| 33 | uint64_t writeCounter = getWriteCounter(); |
| 34 | uint64_t readCounter = getReadCounter(); |
| 35 | if (readCounter > writeCounter) { |
| 36 | return 0; |
| 37 | } |
| 38 | uint64_t delta = writeCounter - readCounter; |
| 39 | if (delta >= mTotalFrames) { |
| 40 | return mTotalFrames; |
| 41 | } |
| 42 | // delta is now guaranteed to fit within the range of a uint32_t |
| 43 | return static_cast<uint32_t>(delta); |
Don Turner | ca6f91a | 2017-09-05 14:52:39 +0100 | [diff] [blame] | 44 | } |
| 45 | |
Thomas Guilbert | f263601 | 2019-07-10 12:16:08 -0700 | [diff] [blame] | 46 | uint32_t FifoControllerBase::getReadIndex() const { |
Phil Burk | 919cd42 | 2019-08-12 17:26:50 -0700 | [diff] [blame] | 47 | // % works with non-power of two sizes |
gfan | e55f983 | 2018-07-25 16:13:34 -0700 | [diff] [blame] | 48 | return static_cast<uint32_t>(getReadCounter() % mTotalFrames); |
Don Turner | ca6f91a | 2017-09-05 14:52:39 +0100 | [diff] [blame] | 49 | } |
| 50 | |
Thomas Guilbert | 5a73fb9 | 2019-07-12 11:54:45 -0700 | [diff] [blame] | 51 | void FifoControllerBase::advanceReadIndex(uint32_t numFrames) { |
| 52 | incrementReadCounter(numFrames); |
Don Turner | ca6f91a | 2017-09-05 14:52:39 +0100 | [diff] [blame] | 53 | } |
| 54 | |
Phil Burk | 919cd42 | 2019-08-12 17:26:50 -0700 | [diff] [blame] | 55 | uint32_t FifoControllerBase::getEmptyFramesAvailable() const { |
| 56 | return static_cast<uint32_t>(mTotalFrames - getFullFramesAvailable()); |
Don Turner | ca6f91a | 2017-09-05 14:52:39 +0100 | [diff] [blame] | 57 | } |
| 58 | |
Thomas Guilbert | f263601 | 2019-07-10 12:16:08 -0700 | [diff] [blame] | 59 | uint32_t FifoControllerBase::getWriteIndex() const { |
Phil Burk | 919cd42 | 2019-08-12 17:26:50 -0700 | [diff] [blame] | 60 | // % works with non-power of two sizes |
| 61 | return static_cast<uint32_t>(getWriteCounter() % mTotalFrames); |
Don Turner | ca6f91a | 2017-09-05 14:52:39 +0100 | [diff] [blame] | 62 | } |
| 63 | |
| 64 | void FifoControllerBase::advanceWriteIndex(uint32_t numFrames) { |
Thomas Guilbert | 5a73fb9 | 2019-07-12 11:54:45 -0700 | [diff] [blame] | 65 | incrementWriteCounter(numFrames); |
Don Turner | ca6f91a | 2017-09-05 14:52:39 +0100 | [diff] [blame] | 66 | } |
| 67 | |
Phil Burk | f61cea3 | 2018-12-17 17:30:21 -0800 | [diff] [blame] | 68 | } // namespace oboe |