NBAIO.h revision 010662326b9c43c703725f933e95e0897f8a6bdd
1010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten/* 2010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten * Copyright (C) 2012 The Android Open Source Project 3010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten * 4010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten * Licensed under the Apache License, Version 2.0 (the "License"); 5010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten * you may not use this file except in compliance with the License. 6010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten * You may obtain a copy of the License at 7010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten * 8010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten * http://www.apache.org/licenses/LICENSE-2.0 9010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten * 10010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten * Unless required by applicable law or agreed to in writing, software 11010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten * distributed under the License is distributed on an "AS IS" BASIS, 12010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten * See the License for the specific language governing permissions and 14010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten * limitations under the License. 15010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten */ 16010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 17010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten#ifndef ANDROID_AUDIO_NBAIO_H 18010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten#define ANDROID_AUDIO_NBAIO_H 19010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 20010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten// Non-blocking audio I/O interface 21010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten// 22010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten// This header file has the abstract interfaces only. Concrete implementation classes are declared 23010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten// elsewhere. Implementations _should_ be non-blocking for all methods, especially read() and 24010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten// write(), but this is not enforced. In general, implementations do not need to be multi-thread 25010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten// safe, and any exceptions are noted in the particular implementation. 26010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 27010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten#include <limits.h> 28010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten#include <stdlib.h> 29010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten#include <utils/RefBase.h> 30010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 31010662326b9c43c703725f933e95e0897f8a6bddGlenn Kastennamespace android { 32010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 33010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten// In addition to the usual status_t 34010662326b9c43c703725f933e95e0897f8a6bddGlenn Kastenenum { 35010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten NEGOTIATE = 0x80000010, // Must (re-)negotiate format. For negotiate() only, the offeree 36010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // doesn't accept offers, and proposes counter-offers 37010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten OVERRUN = 0x80000011, // availableToRead(), read(), or readVia() detected lost input due 38010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // to overrun; an event is counted and the caller should re-try 39010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten UNDERRUN = 0x80000012, // availableToWrite(), write(), or writeVia() detected a gap in 40010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // output due to underrun (not being called often enough, or with 41010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // enough data); an event is counted and the caller should re-try 42010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten}; 43010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 44010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten// Negotiation of format is based on the data provider and data sink, or the data consumer and 45010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten// data source, exchanging prioritized arrays of offers and counter-offers until a single offer is 46010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten// mutually agreed upon. Each offer is an NBAIO_Format. For simplicity and performance, 47010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten// NBAIO_Format is an enum that ties together the most important combinations of the various 48010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten// attributes, rather than a struct with separate fields for format, sample rate, channel count, 49010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten// interleave, packing, alignment, etc. The reason is that NBAIO_Format tries to abstract out only 50010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten// the combinations that are actually needed within AudioFligner. If the list of combinations grows 51010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten// too large, then this decision should be re-visited. 52010662326b9c43c703725f933e95e0897f8a6bddGlenn Kastenenum NBAIO_Format { 53010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten Format_Invalid, 54010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten Format_SR44_1_C2_I16, // 44.1 kHz PCM stereo interleaved 16-bit signed 55010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten Format_SR48_C2_I16, // 48 kHz PCM stereo interleaved 16-bit signed 56010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten Format_SR44_1_C1_I16, // 44.1 kHz PCM mono interleaved 16-bit signed 57010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten Format_SR48_C1_I16, // 48 kHz PCM mono interleaved 16-bit signed 58010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten}; 59010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 60010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten// Return the frame size of an NBAIO_Format in bytes 61010662326b9c43c703725f933e95e0897f8a6bddGlenn Kastensize_t Format_frameSize(NBAIO_Format format); 62010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 63010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten// Return the frame size of an NBAIO_Format as a bit shift 64010662326b9c43c703725f933e95e0897f8a6bddGlenn Kastensize_t Format_frameBitShift(NBAIO_Format format); 65010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 66010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten// Convert a sample rate in Hz and channel count to an NBAIO_Format 67010662326b9c43c703725f933e95e0897f8a6bddGlenn KastenNBAIO_Format Format_from_SR_C(unsigned sampleRate, unsigned channelCount); 68010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 69010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten// Return the sample rate in Hz of an NBAIO_Format 70010662326b9c43c703725f933e95e0897f8a6bddGlenn Kastenunsigned Format_sampleRate(NBAIO_Format format); 71010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 72010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten// Return the channel count of an NBAIO_Format 73010662326b9c43c703725f933e95e0897f8a6bddGlenn Kastenunsigned Format_channelCount(NBAIO_Format format); 74010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 75010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten// Callbacks used by NBAIO_Sink::writeVia() and NBAIO_Source::readVia() below. 76010662326b9c43c703725f933e95e0897f8a6bddGlenn Kastentypedef ssize_t (*writeVia_t)(void *user, void *buffer, size_t count); 77010662326b9c43c703725f933e95e0897f8a6bddGlenn Kastentypedef ssize_t (*readVia_t)(void *user, const void *buffer, size_t count); 78010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 79010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten// Abstract class (interface) representing a data port. 80010662326b9c43c703725f933e95e0897f8a6bddGlenn Kastenclass NBAIO_Port : public RefBase { 81010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 82010662326b9c43c703725f933e95e0897f8a6bddGlenn Kastenpublic: 83010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 84010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // negotiate() must called first. The purpose of negotiate() is to check compatibility of 85010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // formats, not to automatically adapt if they are incompatible. It's the responsibility of 86010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // whoever sets up the graph connections to make sure formats are compatible, and this method 87010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // just verifies that. The edges are "dumb" and don't attempt to adapt to bad connections. 88010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // How it works: offerer proposes an array of formats, in descending order of preference from 89010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // offers[0] to offers[numOffers - 1]. If offeree accepts one of these formats, it returns 90010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // the index of that offer. Otherwise, offeree sets numCounterOffers to the number of 91010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // counter-offers (up to a maximumum of the entry value of numCounterOffers), fills in the 92010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // provided array counterOffers[] with its counter-offers, in descending order of preference 93010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // from counterOffers[0] to counterOffers[numCounterOffers - 1], and returns NEGOTIATE. 94010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // Note that since the offerer allocates space for counter-offers, but only the offeree knows 95010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // how many counter-offers it has, there may be insufficient space for all counter-offers. 96010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // In that case, the offeree sets numCounterOffers to the requested number of counter-offers 97010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // (which is greater than the entry value of numCounterOffers), fills in as many of the most 98010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // important counterOffers as will fit, and returns NEGOTIATE. As this implies a re-allocation, 99010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // it should be used as a last resort. It is preferable for the offerer to simply allocate a 100010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // larger space to begin with, and/or for the offeree to tolerate a smaller space than desired. 101010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // Alternatively, the offerer can pass NULL for offers and counterOffers, and zero for 102010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // numOffers. This indicates that it has not allocated space for any counter-offers yet. 103010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // In this case, the offerree should set numCounterOffers appropriately and return NEGOTIATE. 104010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // Then the offerer will allocate the correct amount of memory and retry. 105010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // Format_Invalid is not allowed as either an offer or counter-offer. 106010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // Returns: 107010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // >= 0 Offer accepted. 108010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // NEGOTIATE No offer accepted, and counter-offer(s) optionally made. See above for details. 109010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten virtual ssize_t negotiate(const NBAIO_Format offers[], size_t numOffers, 110010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten NBAIO_Format counterOffers[], size_t& numCounterOffers); 111010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 112010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // Return the current negotiated format, or Format_Invalid if negotiation has not been done, 113010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // or if re-negotiation is required. 114010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten virtual NBAIO_Format format() const { return mNegotiated ? mFormat : Format_Invalid; } 115010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 116010662326b9c43c703725f933e95e0897f8a6bddGlenn Kastenprotected: 117010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten NBAIO_Port(NBAIO_Format format) : mNegotiated(false), mFormat(format), 118010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten mBitShift(Format_frameBitShift(format)) { } 119010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten virtual ~NBAIO_Port() { } 120010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 121010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // Implementations are free to ignore these if they don't need them 122010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 123010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten bool mNegotiated; // mNegotiated implies (mFormat != Format_Invalid) 124010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten NBAIO_Format mFormat; // (mFormat != Format_Invalid) does not imply mNegotiated 125010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten size_t mBitShift; // assign in parallel with any assignment to mFormat 126010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten}; 127010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 128010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten// Abstract class (interface) representing a non-blocking data sink, for use by a data provider. 129010662326b9c43c703725f933e95e0897f8a6bddGlenn Kastenclass NBAIO_Sink : public NBAIO_Port { 130010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 131010662326b9c43c703725f933e95e0897f8a6bddGlenn Kastenpublic: 132010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 133010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // For the next two APIs: 134010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // 32 bits rolls over after 27 hours at 44.1 kHz; if that concerns you then poll periodically. 135010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 136010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // Return the number of frames written successfully since construction. 137010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten virtual size_t framesWritten() const { return mFramesWritten; } 138010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 139010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // Number of frames lost due to underrun since construction. 140010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten virtual size_t framesUnderrun() const { return 0; } 141010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 142010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // Number of underruns since construction, where a set of contiguous lost frames is one event. 143010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten virtual size_t underruns() const { return 0; } 144010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 145010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // Estimate of number of frames that could be written successfully now without blocking. 146010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // When a write() is actually attempted, the implementation is permitted to return a smaller or 147010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // larger transfer count, however it will make a good faith effort to give an accurate estimate. 148010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // Errors: 149010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // NEGOTIATE (Re-)negotiation is needed. 150010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // UNDERRUN write() has not been called frequently enough, or with enough frames to keep up. 151010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // An underrun event is counted, and the caller should re-try this operation. 152010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // WOULD_BLOCK Determining how many frames can be written without blocking would itself block. 153010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten virtual ssize_t availableToWrite() const { return SSIZE_MAX; } 154010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 155010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // Transfer data to sink from single input buffer. Implies a copy. 156010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // Inputs: 157010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // buffer Non-NULL buffer owned by provider. 158010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // count Maximum number of frames to transfer. 159010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // Return value: 160010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // > 0 Number of frames successfully transferred prior to first error. 161010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // = 0 Count was zero. 162010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // < 0 status_t error occurred prior to the first frame transfer. 163010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // Errors: 164010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // NEGOTIATE (Re-)negotiation is needed. 165010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // WOULD_BLOCK No frames can be transferred without blocking. 166010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // UNDERRUN write() has not been called frequently enough, or with enough frames to keep up. 167010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // An underrun event is counted, and the caller should re-try this operation. 168010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten virtual ssize_t write(const void *buffer, size_t count) = 0; 169010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 170010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // Transfer data to sink using a series of callbacks. More suitable for zero-fill, synthesis, 171010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // and non-contiguous transfers (e.g. circular buffer or writev). 172010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // Inputs: 173010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // via Callback function that the sink will call as many times as needed to consume data. 174010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // total Estimate of the number of frames the provider has available. This is an estimate, 175010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // and it can provide a different number of frames during the series of callbacks. 176010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // user Arbitrary void * reserved for data provider. 177010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // block Number of frames per block, that is a suggested value for 'count' in each callback. 178010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // Zero means no preference. This parameter is a hint only, and may be ignored. 179010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // Return value: 180010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // > 0 Total number of frames successfully transferred prior to first error. 181010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // = 0 Count was zero. 182010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // < 0 status_t error occurred prior to the first frame transfer. 183010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // Errors: 184010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // NEGOTIATE (Re-)negotiation is needed. 185010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // WOULD_BLOCK No frames can be transferred without blocking. 186010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // UNDERRUN write() has not been called frequently enough, or with enough frames to keep up. 187010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // An underrun event is counted, and the caller should re-try this operation. 188010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // 189010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // The 'via' callback is called by the data sink as follows: 190010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // Inputs: 191010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // user Arbitrary void * reserved for data provider. 192010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // buffer Non-NULL buffer owned by sink that callback should fill in with data, 193010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // up to a maximum of 'count' frames. 194010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // count Maximum number of frames to transfer during this callback. 195010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // Return value: 196010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // > 0 Number of frames successfully transferred during this callback prior to first error. 197010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // = 0 Count was zero. 198010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // < 0 status_t error occurred prior to the first frame transfer during this callback. 199010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten virtual ssize_t writeVia(writeVia_t via, size_t total, void *user, size_t block = 0); 200010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 201010662326b9c43c703725f933e95e0897f8a6bddGlenn Kastenprotected: 202010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten NBAIO_Sink(NBAIO_Format format = Format_Invalid) : NBAIO_Port(format), mFramesWritten(0) { } 203010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten virtual ~NBAIO_Sink() { } 204010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 205010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // Implementations are free to ignore these if they don't need them 206010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten size_t mFramesWritten; 207010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten}; 208010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 209010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten// Abstract class (interface) representing a non-blocking data source, for use by a data consumer. 210010662326b9c43c703725f933e95e0897f8a6bddGlenn Kastenclass NBAIO_Source : public NBAIO_Port { 211010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 212010662326b9c43c703725f933e95e0897f8a6bddGlenn Kastenpublic: 213010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 214010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // For the next two APIs: 215010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // 32 bits rolls over after 27 hours at 44.1 kHz; if that concerns you then poll periodically. 216010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 217010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // Number of frames read successfully since construction. 218010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten virtual size_t framesRead() const { return mFramesRead; } 219010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 220010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // Number of frames lost due to overrun since construction. 221010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // Not const because implementations may need to do I/O. 222010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten virtual size_t framesOverrun() /*const*/ { return 0; } 223010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 224010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // Number of overruns since construction, where a set of contiguous lost frames is one event. 225010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // Not const because implementations may need to do I/O. 226010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten virtual size_t overruns() /*const*/ { return 0; } 227010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 228010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // Estimate of number of frames that could be read successfully now. 229010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // When a read() is actually attempted, the implementation is permitted to return a smaller or 230010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // larger transfer count, however it will make a good faith effort to give an accurate estimate. 231010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // Errors: 232010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // NEGOTIATE (Re-)negotiation is needed. 233010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // OVERRUN One or more frames were lost due to overrun, try again to read more recent data. 234010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // WOULD_BLOCK Determining how many frames can be read without blocking would itself block. 235010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten virtual ssize_t availableToRead() { return SSIZE_MAX; } 236010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 237010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // Transfer data from source into single destination buffer. Implies a copy. 238010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // Inputs: 239010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // buffer Non-NULL destination buffer owned by consumer. 240010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // count Maximum number of frames to transfer. 241010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // Return value: 242010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // > 0 Number of frames successfully transferred prior to first error. 243010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // = 0 Count was zero. 244010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // < 0 status_t error occurred prior to the first frame transfer. 245010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // Errors: 246010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // NEGOTIATE (Re-)negotiation is needed. 247010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // WOULD_BLOCK No frames can be transferred without blocking. 248010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // OVERRUN read() has not been called frequently enough, or with enough frames to keep up. 249010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // One or more frames were lost due to overrun, try again to read more recent data. 250010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten virtual ssize_t read(void *buffer, size_t count) = 0; 251010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 252010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // Transfer data from source using a series of callbacks. More suitable for zero-fill, 253010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // synthesis, and non-contiguous transfers (e.g. circular buffer or readv). 254010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // Inputs: 255010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // via Callback function that the source will call as many times as needed to provide data. 256010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // total Estimate of the number of frames the consumer desires. This is an estimate, 257010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // and it can consume a different number of frames during the series of callbacks. 258010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // user Arbitrary void * reserved for data consumer. 259010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // block Number of frames per block, that is a suggested value for 'count' in each callback. 260010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // Zero means no preference. This parameter is a hint only, and may be ignored. 261010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // Return value: 262010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // > 0 Total number of frames successfully transferred prior to first error. 263010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // = 0 Count was zero. 264010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // < 0 status_t error occurred prior to the first frame transfer. 265010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // Errors: 266010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // NEGOTIATE (Re-)negotiation is needed. 267010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // WOULD_BLOCK No frames can be transferred without blocking. 268010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // OVERRUN read() has not been called frequently enough, or with enough frames to keep up. 269010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // One or more frames were lost due to overrun, try again to read more recent data. 270010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // 271010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // The 'via' callback is called by the data source as follows: 272010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // Inputs: 273010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // user Arbitrary void * reserved for data consumer. 274010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // dest Non-NULL buffer owned by source that callback should consume data from, 275010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // up to a maximum of 'count' frames. 276010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // count Maximum number of frames to transfer during this callback. 277010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // Return value: 278010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // > 0 Number of frames successfully transferred during this callback prior to first error. 279010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // = 0 Count was zero. 280010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // < 0 status_t error occurred prior to the first frame transfer during this callback. 281010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten virtual ssize_t readVia(readVia_t via, size_t total, void *user, size_t block = 0); 282010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 283010662326b9c43c703725f933e95e0897f8a6bddGlenn Kastenprotected: 284010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten NBAIO_Source(NBAIO_Format format = Format_Invalid) : NBAIO_Port(format), mFramesRead(0) { } 285010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten virtual ~NBAIO_Source() { } 286010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 287010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // Implementations are free to ignore these if they don't need them 288010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten size_t mFramesRead; 289010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten}; 290010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 291010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten} // namespace android 292010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 293010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten#endif // ANDROID_AUDIO_NBAIO_H 294