Use modulo position variables in AudioTrack and AudioRecord (90e8a97d) · Commits · e / os / android_frameworks_av

include/media/AudioRecord.h

+4 −3

Original line number	Diff line number	Diff line
		@@ -20,6 +20,7 @@
		#include <cutils/sched_policy.h>
		#include <media/AudioSystem.h>
		#include <media/IAudioRecord.h>
		#include <media/Modulo.h>
		#include <utils/threads.h>

		namespace android {
		@@ -526,7 +527,7 @@ private:

		// caller must hold lock on mLock for all _l methods

		status_t openRecord_l(size_t epoch, const String16& opPackageName);
		status_t openRecord_l(const Modulo<uint32_t> &epoch, const String16& opPackageName);

		// FIXME enum is faster than strcmp() for parameter 'from'
		status_t restoreRecord_l(const char *from);
		@@ -556,9 +557,9 @@ private:
		bool mRetryOnPartialBuffer; // sleep and retry after partial obtainBuffer()
		uint32_t mObservedSequence; // last observed value of mSequence

		uint32_t mMarkerPosition; // in wrapping (overflow) frame units
		Modulo<uint32_t> mMarkerPosition; // in wrapping (overflow) frame units
		bool mMarkerReached;
		uint32_t mNewPosition; // in frames
		Modulo<uint32_t> mNewPosition; // in frames
		uint32_t mUpdatePeriod; // in frames, zero means no EVENT_NEW_POS

		status_t mStatus;

include/media/AudioTrack.h

+7 −6

Original line number	Diff line number	Diff line
		@@ -22,6 +22,7 @@
		#include <media/AudioTimestamp.h>
		#include <media/IAudioTrack.h>
		#include <media/AudioResamplerPublic.h>
		#include <media/Modulo.h>
		#include <utils/threads.h>

		namespace android {
		@@ -798,7 +799,7 @@ protected:
		{ return (mFlags & AUDIO_OUTPUT_FLAG_DIRECT) != 0; }

		// increment mPosition by the delta of mServer, and return new value of mPosition
		uint32_t updateAndGetPosition_l();
		Modulo<uint32_t> updateAndGetPosition_l();

		// check sample rate and speed is compatible with AudioTrack
		bool isSampleRateSpeedAllowed_l(uint32_t sampleRate, float speed) const;
		@@ -885,19 +886,19 @@ protected:
		bool mRetryOnPartialBuffer; // sleep and retry after partial obtainBuffer()
		uint32_t mObservedSequence; // last observed value of mSequence

		uint32_t mMarkerPosition; // in wrapping (overflow) frame units
		Modulo<uint32_t> mMarkerPosition; // in wrapping (overflow) frame units
		bool mMarkerReached;
		uint32_t mNewPosition; // in frames
		Modulo<uint32_t> mNewPosition; // in frames
		uint32_t mUpdatePeriod; // in frames, zero means no EVENT_NEW_POS

		uint32_t mServer; // in frames, last known mProxy->getPosition()
		Modulo<uint32_t> mServer; // in frames, last known mProxy->getPosition()
		// which is count of frames consumed by server,
		// reset by new IAudioTrack,
		// whether it is reset by stop() is TBD
		uint32_t mPosition; // in frames, like mServer except continues
		Modulo<uint32_t> mPosition; // in frames, like mServer except continues
		// monotonically after new IAudioTrack,
		// and could be easily widened to uint64_t
		uint32_t mReleased; // in frames, count of frames released to server
		Modulo<uint32_t> mReleased; // count of frames released to server
		// but not necessarily consumed by server,
		// reset by stop() but continues monotonically
		// after new IAudioTrack to restore mPosition,

include/media/Modulo.h

0 → 100644

+220 −0

Original line number	Diff line number	Diff line
		/*
		* Copyright 2015 The Android Open Source Project
		*
		* Licensed under the Apache License, Version 2.0 (the "License");
		* you may not use this file except in compliance with the License.
		* You may obtain a copy of the License at
		*
		* http://www.apache.org/licenses/LICENSE-2.0
		*
		* Unless required by applicable law or agreed to in writing, software
		* distributed under the License is distributed on an "AS IS" BASIS,
		* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
		* See the License for the specific language governing permissions and
		* limitations under the License.
		*/

		#ifndef ANDROID_MODULO_H
		#define ANDROID_MODULO_H

		namespace android {

		// Modulo class is used for intentionally wrapping variables such as
		// counters and timers.
		//
		// It may also be used for variables whose computation depends on the
		// associativity of addition or subtraction.
		//
		// Features:
		// 1) Modulo checks type sizes before performing operations to ensure
		// that the wrap points match. This is critical for safe modular arithmetic.
		// 2) Modulo returns Modulo types from arithmetic operations, thereby
		// avoiding unintentional use in a non-modular computation. A Modulo
		// type is converted to its base non-Modulo type through the value() function.
		// 3) Modulo separates out overflowable types from non-overflowable types.
		// A signed overflow is technically undefined in C and C++.
		// Modulo types do not participate in sanitization.
		// 4) Modulo comparisons are based on signed differences to account for wrap;
		// this is not the same as the direct comparison of values.
		// 5) Safe use of binary arithmetic operations relies on conversions of
		// signed operands to unsigned operands (which are modular arithmetic safe).
		// Conversions which are implementation-defined are assumed to use 2's complement
		// representation. (See A, B, C, D from the ISO/IEC FDIS 14882
		// Information technology — Programming languages — C++).
		//
		// A: ISO/IEC 14882:2011(E) p84 section 4.7 Integral conversions
		// (2) If the destination type is unsigned, the resulting value is the least unsigned
		// integer congruent to the source integer (modulo 2^n where n is the number of bits
		// used to represent the unsigned type). [ Note: In a two’s complement representation,
		// this conversion is conceptual and there is no change in the bit pattern (if there
		// is no truncation). — end note ]
		// (3) If the destination type is signed, the value is unchanged if it can be represented
		// in the destination type (and bit-field width); otherwise, the value is
		// implementation-defined.
		//
		// B: ISO/IEC 14882:2011(E) p88 section 5 Expressions
		// (9) Many binary operators that expect operands of arithmetic or enumeration type
		// cause conversions and yield result types in a similar way. The purpose is to
		// yield a common type, which is also the type of the result. This pattern is called
		// the usual arithmetic conversions, which are defined as follows:
		// [...]
		// Otherwise, if both operands have signed integer types or both have unsigned
		// integer types, the operand with the type of lesser integer conversion rank shall be
		// converted to the type of the operand with greater rank.
		// — Otherwise, if the operand that has unsigned integer type has rank greater than
		// or equal to the rank of the type of the other operand, the operand with signed
		// integer type shall be converted to the type of the operand with unsigned integer type.
		//
		// C: ISO/IEC 14882:2011(E) p86 section 4.13 Integer conversion rank
		// [...] The rank of long long int shall be greater than the rank of long int,
		// which shall be greater than the rank of int, which shall be greater than the
		// rank of short int, which shall be greater than the rank of signed char.
		// — The rank of any unsigned integer type shall equal the rank of the corresponding
		// signed integer type.
		//
		// D: ISO/IEC 14882:2011(E) p75 section 3.9.1 Fundamental types
		// [...] Unsigned integers, declared unsigned, shall obey the laws of arithmetic modulo
		// 2^n where n is the number of bits in the value representation of that particular
		// size of integer.
		//
		// Note:
		// Other libraries do exist for safe integer operations which can detect the
		// possibility of overflow (SafeInt from MS and safe-iop in android).
		// Signed safe computation is also possible from the art header safe_math.h.

		template <typename T> class Modulo {
		T mValue;

		public:
		typedef typename std::make_signed<T>::type signedT;
		typedef typename std::make_unsigned<T>::type unsignedT;

		Modulo() { } // intentionally uninitialized data
		Modulo(const T &value) { mValue = value; }
		const T & value() const { return mValue; } // not assignable
		signedT signedValue() const { return mValue; }
		unsignedT unsignedValue() const { return mValue; }
		void getValue(T value) const { value = mValue; } // more type safe than value()

		// modular operations valid only if size of T <= size of S.
		template <typename S>
		__attribute__((no_sanitize("integer")))
		Modulo<T> operator +=(const Modulo<S> &other) {
		static_assert(sizeof(T) <= sizeof(S), "argument size mismatch");
		mValue += other.unsignedValue();
		return *this;
		}

		template <typename S>
		__attribute__((no_sanitize("integer")))
		Modulo<T> operator -=(const Modulo<S> &other) {
		static_assert(sizeof(T) <= sizeof(S), "argument size mismatch");
		mValue -= other.unsignedValue();
		return *this;
		}

		// modular operations resulting in a value valid only at the smaller of the two
		// Modulo base type sizes, but we only allow equal sizes to avoid confusion.
		template <typename S>
		__attribute__((no_sanitize("integer")))
		const Modulo<T> operator +(const Modulo<S> &other) const {
		static_assert(sizeof(T) == sizeof(S), "argument size mismatch");
		return Modulo<T>(mValue + other.unsignedValue());
		}

		template <typename S>
		__attribute__((no_sanitize("integer")))
		const Modulo<T> operator -(const Modulo<S> &other) const {
		static_assert(sizeof(T) == sizeof(S), "argument size mismatch");
		return Modulo<T>(mValue - other.unsignedValue());
		}

		// modular operations that should be checked only at the smaller of
		// the two type sizes, but we only allow equal sizes to avoid confusion.
		//
		// Caution: These relational and comparison operations are not equivalent to
		// the base type operations.
		template <typename S>
		__attribute__((no_sanitize("integer")))
		bool operator >(const Modulo<S> &other) const {
		static_assert(sizeof(T) == sizeof(S), "argument size mismatch");
		return static_cast<signedT>(mValue - other.unsignedValue()) > 0;
		}

		template <typename S>
		__attribute__((no_sanitize("integer")))
		bool operator >=(const Modulo<S> &other) const {
		static_assert(sizeof(T) == sizeof(S), "argument size mismatch");
		return static_cast<signedT>(mValue - other.unsignedValue()) >= 0;
		}

		template <typename S>
		__attribute__((no_sanitize("integer")))
		bool operator ==(const Modulo<S> &other) const {
		static_assert(sizeof(T) == sizeof(S), "argument size mismatch");
		return static_cast<signedT>(mValue - other.unsignedValue()) == 0;
		}

		template <typename S>
		__attribute__((no_sanitize("integer")))
		bool operator <=(const Modulo<S> &other) const {
		static_assert(sizeof(T) == sizeof(S), "argument size mismatch");
		return static_cast<signedT>(mValue - other.unsignedValue()) <= 0;
		}

		template <typename S>
		__attribute__((no_sanitize("integer")))
		bool operator <(const Modulo<S> &other) const {
		static_assert(sizeof(T) == sizeof(S), "argument size mismatch");
		return static_cast<signedT>(mValue - other.unsignedValue()) < 0;
		}


		// modular operations with a non-Modulo type allowed with wrapping
		// because there should be no confusion as to the meaning.
		template <typename S>
		__attribute__((no_sanitize("integer")))
		Modulo<T> operator +=(const S &other) {
		mValue += unsignedT(other);
		return *this;
		}

		template <typename S>
		__attribute__((no_sanitize("integer")))
		Modulo<T> operator -=(const S &other) {
		mValue -= unsignedT(other);
		return *this;
		}

		// modular operations with a non-Modulo type allowed with wrapping,
		// but we restrict this only when size of T is greater than or equal to
		// the size of S to avoid confusion with the nature of overflow.
		//
		// Use of this follows left-associative style.
		//
		// Note: a Modulo type may be promoted by using "differences" off of
		// a larger sized type, but we do not automate this.
		template <typename S>
		__attribute__((no_sanitize("integer")))
		const Modulo<T> operator +(const S &other) const {
		static_assert(sizeof(T) >= sizeof(S), "argument size mismatch");
		return Modulo<T>(mValue + unsignedT(other));
		}

		template <typename S>
		__attribute__((no_sanitize("integer")))
		const Modulo<T> operator -(const S &other) const {
		static_assert(sizeof(T) >= sizeof(S), "argument size mismatch");
		return Modulo<T>(mValue - unsignedT(other));
		}

		// multiply is intentionally omitted, but it is a common operator in
		// modular arithmetic.

		// shift operations are intentionally omitted, but perhaps useful.
		// For example, left-shifting a negative number is undefined in C++11.
		};

		} // namespace android

		#endif /* ANDROID_MODULO_H */

include/private/media/AudioTrackShared.h

+5 −4

Original line number	Diff line number	Diff line
		@@ -26,6 +26,7 @@
		#include <utils/RefBase.h>
		#include <audio_utils/roundup.h>
		#include <media/AudioResamplerPublic.h>
		#include <media/Modulo.h>
		#include <media/SingleStateQueue.h>

		namespace android {
		@@ -280,11 +281,11 @@ public:
		// Call to force an obtainBuffer() to return quickly with -EINTR
		void interrupt();

		size_t getPosition() {
		Modulo<uint32_t> getPosition() {
		return mEpoch + mCblk->mServer;
		}

		void setEpoch(size_t epoch) {
		void setEpoch(const Modulo<uint32_t> &epoch) {
		mEpoch = epoch;
		}

		@@ -300,14 +301,14 @@ public:
		// in order for the client to be aligned at start of buffer
		virtual size_t getMisalignment();

		size_t getEpoch() const {
		Modulo<uint32_t> getEpoch() const {
		return mEpoch;
		}

		size_t getFramesFilled();

		private:
		size_t mEpoch;
		Modulo<uint32_t> mEpoch;
		};

		// ----------------------------------------------------------------------------

media/libmedia/AudioRecord.cpp

+12 −12

Original line number	Diff line number	Diff line
		@@ -396,7 +396,7 @@ status_t AudioRecord::getMarkerPosition(uint32_t *marker) const
		}

		AutoMutex lock(mLock);
		*marker = mMarkerPosition;
		mMarkerPosition.getValue(marker);

		return NO_ERROR;
		}
		@@ -438,7 +438,7 @@ status_t AudioRecord::getPosition(uint32_t *position) const
		}

		AutoMutex lock(mLock);
		*position = mProxy->getPosition();
		mProxy->getPosition().getValue(position);

		return NO_ERROR;
		}
		@@ -480,7 +480,7 @@ audio_port_handle_t AudioRecord::getRoutedDeviceId() {
		// -------------------------------------------------------------------------

		// must be called with mLock held
		status_t AudioRecord::openRecord_l(size_t epoch, const String16& opPackageName)
		status_t AudioRecord::openRecord_l(const Modulo<uint32_t> &epoch, const String16& opPackageName)
		{
		const sp<IAudioFlinger>& audioFlinger = AudioSystem::get_audio_flinger();
		if (audioFlinger == 0) {
		@@ -890,23 +890,23 @@ nsecs_t AudioRecord::processAudioBuffer()
		}

		// Get current position of server
		size_t position = mProxy->getPosition();
		Modulo<uint32_t> position(mProxy->getPosition());

		// Manage marker callback
		bool markerReached = false;
		size_t markerPosition = mMarkerPosition;
		Modulo<uint32_t> markerPosition(mMarkerPosition);
		// FIXME fails for wraparound, need 64 bits
		if (!mMarkerReached && (markerPosition > 0) && (position >= markerPosition)) {
		if (!mMarkerReached && markerPosition.value() > 0 && position >= markerPosition) {
		mMarkerReached = markerReached = true;
		}

		// Determine the number of new position callback(s) that will be needed, while locked
		size_t newPosCount = 0;
		size_t newPosition = mNewPosition;
		Modulo<uint32_t> newPosition(mNewPosition);
		uint32_t updatePeriod = mUpdatePeriod;
		// FIXME fails for wraparound, need 64 bits
		if (updatePeriod > 0 && position >= newPosition) {
		newPosCount = ((position - newPosition) / updatePeriod) + 1;
		newPosCount = ((position - newPosition).value() / updatePeriod) + 1;
		mNewPosition += updatePeriod * newPosCount;
		}

		@@ -933,7 +933,7 @@ nsecs_t AudioRecord::processAudioBuffer()
		mCbf(EVENT_MARKER, mUserData, &markerPosition);
		}
		while (newPosCount > 0) {
		size_t temp = newPosition;
		size_t temp = newPosition.value(); // FIXME size_t != uint32_t
		mCbf(EVENT_NEW_POS, mUserData, &temp);
		newPosition += updatePeriod;
		newPosCount--;
		@@ -951,10 +951,10 @@ nsecs_t AudioRecord::processAudioBuffer()
		// Compute the estimated time until the next timed event (position, markers)
		uint32_t minFrames = ~0;
		if (!markerReached && position < markerPosition) {
		minFrames = markerPosition - position;
		minFrames = (markerPosition - position).value();
		}
		if (updatePeriod > 0) {
		uint32_t remaining = newPosition - position;
		uint32_t remaining = (newPosition - position).value();
		if (remaining < minFrames) {
		minFrames = remaining;
		}
		@@ -1087,7 +1087,7 @@ status_t AudioRecord::restoreRecord_l(const char *from)
		// if the new IAudioRecord is created, openRecord_l() will modify the
		// following member variables: mAudioRecord, mCblkMemory, mCblk, mBufferMemory.
		// It will also delete the strong references on previous IAudioRecord and IMemory
		size_t position = mProxy->getPosition();
		Modulo<uint32_t> position(mProxy->getPosition());
		mNewPosition = position + mUpdatePeriod;
		status_t result = openRecord_l(position, mOpPackageName);
		if (result == NO_ERROR) {