15c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles)/* 25c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) * Copyright (C) 2012 Google Inc. All rights reserved. 35c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) * 45c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) * Redistribution and use in source and binary forms, with or without 55c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) * modification, are permitted provided that the following conditions 65c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) * are met: 75c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) * 85c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) * 1. Redistributions of source code must retain the above copyright 95c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) * notice, this list of conditions and the following disclaimer. 105c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) * 2. Redistributions in binary form must reproduce the above copyright 115c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) * notice, this list of conditions and the following disclaimer in the 125c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) * documentation and/or other materials provided with the distribution. 135c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) * 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of 145c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) * its contributors may be used to endorse or promote products derived 155c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) * from this software without specific prior written permission. 165c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) * 175c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY 185c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 195c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 205c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY 215c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 225c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 235c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND 245c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 255c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 265c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 275c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) */ 285c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) 295c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles)#ifndef AudioFIFO_h 305c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles)#define AudioFIFO_h 315c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) 321e202183a5dc46166763171984b285173f8585e5Torne (Richard Coles)#include "platform/audio/AudioBus.h" 335c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) 34c1847b1379d12d0e05df27436bf19a9b1bf12deaTorne (Richard Coles)namespace blink { 355c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) 365c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles)class AudioFIFO { 375c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles)public: 385c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) // Create a FIFO large enough to hold |fifoLength| frames of data of |numberOfChannels| channels. 395c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) AudioFIFO(unsigned numberOfChannels, size_t fifoLength); 405c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) 415c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) // Push the data from the bus into the FIFO. 425c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) void push(const AudioBus*); 435c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) 445c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) // Consume |framesToConsume| frames of data from the FIFO and put them in |destination|. The 455c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) // corresponding frames are removed from the FIFO. 465c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) void consume(AudioBus* destination, size_t framesToConsume); 475c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) 485c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) // Number of frames of data that are currently in the FIFO. 495c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) size_t framesInFifo() const { return m_framesInFifo; } 505c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) 515c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles)private: 525c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) // Update the FIFO index by the step, with appropriate wrapping around the endpoint. 535c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) int updateIndex(int index, int step) { return (index + step) % m_fifoLength; } 545c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) 555c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) void findWrapLengths(size_t index, size_t providerSize, size_t& part1Length, size_t& part2Length); 5602772c6a72f1ee0b226341a4f4439970c29fc861Ben Murdoch 575c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) // The FIFO itself. In reality, the FIFO is a circular buffer. 5881a5157921f1d2a7ff6aae115bfe3c139b38a5c8Torne (Richard Coles) RefPtr<AudioBus> m_fifoAudioBus; 595c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) 605c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) // The total available space in the FIFO. 615c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) size_t m_fifoLength; 625c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) 635c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) // The number of actual elements in the FIFO 645c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) size_t m_framesInFifo; 655c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) 665c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) // Where to start reading from the FIFO. 675c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) size_t m_readIndex; 685c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) 695c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) // Where to start writing to the FIFO. 705c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) size_t m_writeIndex; 715c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles)}; 725c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) 73c1847b1379d12d0e05df27436bf19a9b1bf12deaTorne (Richard Coles)} // namespace blink 745c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles) 755c87bf8b86a7c82ef50fb7a89697d8e02e2553beTorne (Richard Coles)#endif // AudioFIFO.h 76