audio_utils/fifo.cpp - platform/system/media - Gitiles

 /*
  * Copyright (C) 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.
  */

 //#define LOG_NDEBUG 0
 #define LOG_TAG "audio_utils_fifo"

 #include <limits.h>
 #include <stdlib.h>
 #include <string.h>
 #include <audio_utils/fifo.h>
 #include <audio_utils/roundup.h>
 #include <cutils/log.h>
 #include <utils/Errors.h>

 audio_utils_fifo_base::audio_utils_fifo_base(uint32_t frameCount)
         __attribute__((no_sanitize("integer"))) :
     mFrameCount(frameCount), mFrameCountP2(roundup(frameCount)),
     mFudgeFactor(mFrameCountP2 - mFrameCount),
     mSharedRear(0), mThrottleFront(NULL)
 {
     // actual upper bound on frameCount will depend on the frame size
     LOG_ALWAYS_FATAL_IF(frameCount == 0 || frameCount > ((uint32_t) INT_MAX));
 }

 audio_utils_fifo_base::~audio_utils_fifo_base()
 {
 }

 uint32_t audio_utils_fifo_base::sum(uint32_t index, uint32_t increment)
         __attribute__((no_sanitize("integer")))
 {
     if (mFudgeFactor) {
         uint32_t mask = mFrameCountP2 - 1;
         ALOG_ASSERT((index & mask) < mFrameCount);
         ALOG_ASSERT(increment <= mFrameCountP2);
         if ((index & mask) + increment >= mFrameCount) {
             increment += mFudgeFactor;
         }
         index += increment;
         ALOG_ASSERT((index & mask) < mFrameCount);
         return index;
     } else {
         return index + increment;
     }
 }

 int32_t audio_utils_fifo_base::diff(uint32_t rear, uint32_t front, size_t *lost)
         __attribute__((no_sanitize("integer")))
 {
     uint32_t diff = rear - front;
     if (mFudgeFactor) {
         uint32_t mask = mFrameCountP2 - 1;
         uint32_t rearMasked = rear & mask;
         uint32_t frontMasked = front & mask;
         if (rearMasked >= mFrameCount || frontMasked >= mFrameCount) {
             return -EIO;
         }
         uint32_t genDiff = (rear & ~mask) - (front & ~mask);
         if (genDiff != 0) {
             if (genDiff > mFrameCountP2) {
                 if (lost != NULL) {
                     // TODO provide a more accurate estimate
                     *lost = (genDiff / mFrameCountP2) * mFrameCount;
                 }
                 return -EOVERFLOW;
             }
             diff -= mFudgeFactor;
         }
     }
     // FIFO should not be overfull
     if (diff > mFrameCount) {
         if (lost != NULL) {
             *lost = diff - mFrameCount;
         }
         return -EOVERFLOW;
     }
     return (int32_t) diff;
 }

 ////////////////////////////////////////////////////////////////////////////////

 audio_utils_fifo::audio_utils_fifo(uint32_t frameCount, uint32_t frameSize, void *buffer)
         __attribute__((no_sanitize("integer"))) :
     audio_utils_fifo_base(frameCount), mFrameSize(frameSize), mBuffer(buffer)
 {
     // maximum value of frameCount * frameSize is INT_MAX (2^31 - 1), not 2^31, because we need to
     // be able to distinguish successful and error return values from read and write.
     LOG_ALWAYS_FATAL_IF(frameCount == 0 || frameSize == 0 || buffer == NULL ||
             frameCount > ((uint32_t) INT_MAX) / frameSize);
 }

 audio_utils_fifo::~audio_utils_fifo()
 {
 }

 ////////////////////////////////////////////////////////////////////////////////

 audio_utils_fifo_provider::audio_utils_fifo_provider() :
     mObtained(0)
 {
 }

 audio_utils_fifo_provider::~audio_utils_fifo_provider()
 {
 }

 ////////////////////////////////////////////////////////////////////////////////

 audio_utils_fifo_writer::audio_utils_fifo_writer(audio_utils_fifo& fifo) :
     audio_utils_fifo_provider(), mFifo(fifo), mLocalRear(0)
 {
 }

 audio_utils_fifo_writer::~audio_utils_fifo_writer()
 {
 }

 ssize_t audio_utils_fifo_writer::write(const void *buffer, size_t count)
         __attribute__((no_sanitize("integer")))
 {
     audio_utils_iovec iovec[2];
     ssize_t availToWrite = obtain(iovec, count);
     if (availToWrite > 0) {
         memcpy((char *) mFifo.mBuffer + iovec[0].mOffset * mFifo.mFrameSize, buffer,
                 iovec[0].mLength * mFifo.mFrameSize);
         if (iovec[1].mLength > 0) {
             memcpy((char *) mFifo.mBuffer + iovec[1].mOffset * mFifo.mFrameSize,
                     (char *) buffer + (iovec[0].mLength * mFifo.mFrameSize),
                     iovec[1].mLength * mFifo.mFrameSize);
         }
         release(availToWrite);
     }
     return availToWrite;
 }

 ssize_t audio_utils_fifo_writer::obtain(audio_utils_iovec iovec[2], size_t count)
         __attribute__((no_sanitize("integer")))
 {
     size_t availToWrite;
     if (mFifo.mThrottleFront != NULL) {
         uint32_t front = (uint32_t) atomic_load_explicit(mFifo.mThrottleFront,
                 std::memory_order_acquire);
         int32_t filled = mFifo.diff(mLocalRear, front, NULL /*lost*/);
         if (filled < 0) {
             mObtained = 0;
             return (ssize_t) filled;
         }
         availToWrite = (size_t) mFifo.mFrameCount - (size_t) filled;
     } else {
         availToWrite = mFifo.mFrameCount;
     }
     if (availToWrite > count) {
         availToWrite = count;
     }
     uint32_t rearMasked = mLocalRear & (mFifo.mFrameCountP2 - 1);
     size_t part1 = mFifo.mFrameCount - rearMasked;
     if (part1 > availToWrite) {
         part1 = availToWrite;
     }
     size_t part2 = part1 > 0 ? availToWrite - part1 : 0;
     iovec[0].mOffset = rearMasked;
     iovec[0].mLength = part1;
     iovec[1].mOffset = 0;
     iovec[1].mLength = part2;
     mObtained = availToWrite;
     return availToWrite;
 }

 void audio_utils_fifo_writer::release(size_t count)
         __attribute__((no_sanitize("integer")))
 {
     if (count > 0) {
         LOG_ALWAYS_FATAL_IF(count > mObtained);
         mLocalRear = mFifo.sum(mLocalRear, count);
         atomic_store_explicit(&mFifo.mSharedRear, (uint_fast32_t) mLocalRear,
                 std::memory_order_release);
         mObtained -= count;
     }
 }

 ////////////////////////////////////////////////////////////////////////////////

 audio_utils_fifo_reader::audio_utils_fifo_reader(audio_utils_fifo& fifo, bool throttlesWriter) :
     audio_utils_fifo_provider(), mFifo(fifo), mLocalFront(0), mSharedFront(0)
 {
     if (throttlesWriter) {
         LOG_ALWAYS_FATAL_IF(fifo.mThrottleFront != NULL);
         fifo.mThrottleFront = &mSharedFront;
     }
 }

 audio_utils_fifo_reader::~audio_utils_fifo_reader()
 {
     // TODO Need a way to pass throttle capability to the another reader, should one reader exit.
     if (mFifo.mThrottleFront == &mSharedFront) {
         mFifo.mThrottleFront = NULL;
     }
 }

 ssize_t audio_utils_fifo_reader::read(void *buffer, size_t count, size_t *lost)
         __attribute__((no_sanitize("integer")))
 {
     audio_utils_iovec iovec[2];
     ssize_t availToRead = obtain(iovec, count, lost);
     if (availToRead > 0) {
         memcpy(buffer, (char *) mFifo.mBuffer + iovec[0].mOffset * mFifo.mFrameSize,
                 iovec[0].mLength * mFifo.mFrameSize);
         if (iovec[1].mLength > 0) {
             memcpy((char *) buffer + (iovec[0].mLength * mFifo.mFrameSize),
                     (char *) mFifo.mBuffer + iovec[1].mOffset * mFifo.mFrameSize,
                     iovec[1].mLength * mFifo.mFrameSize);
         }
         release(availToRead);
     }
     return availToRead;
 }

 ssize_t audio_utils_fifo_reader::obtain(audio_utils_iovec iovec[2], size_t count)
         __attribute__((no_sanitize("integer")))
 {
     return obtain(iovec, count, NULL);
 }

 void audio_utils_fifo_reader::release(size_t count)
         __attribute__((no_sanitize("integer")))
 {
     if (count > 0) {
         LOG_ALWAYS_FATAL_IF(count > mObtained);
         mLocalFront = mFifo.sum(mLocalFront, count);
         if (mFifo.mThrottleFront == &mSharedFront) {
             atomic_store_explicit(&mSharedFront, (uint_fast32_t) mLocalFront,
                     std::memory_order_release);
         }
         mObtained -= count;
     }
 }

 ssize_t audio_utils_fifo_reader::obtain(audio_utils_iovec iovec[2], size_t count, size_t *lost)
         __attribute__((no_sanitize("integer")))
 {
     uint32_t rear = (uint32_t) atomic_load_explicit(&mFifo.mSharedRear,
             std::memory_order_acquire);
     int32_t filled = mFifo.diff(rear, mLocalFront, lost);
     if (filled < 0) {
         if (filled == android::BAD_INDEX) {
             mLocalFront = rear;
         }
         mObtained = 0;
         return (ssize_t) filled;
     }
     size_t availToRead = (size_t) filled;
     if (availToRead > count) {
         availToRead = count;
     }
     uint32_t frontMasked = mLocalFront & (mFifo.mFrameCountP2 - 1);
     size_t part1 = mFifo.mFrameCount - frontMasked;
     if (part1 > availToRead) {
         part1 = availToRead;
     }
     size_t part2 = part1 > 0 ? availToRead - part1 : 0;
     iovec[0].mOffset = frontMasked;
     iovec[0].mLength = part1;
     iovec[1].mOffset = 0;
     iovec[1].mLength = part2;
     mObtained = availToRead;
     return availToRead;
 }
	/*
	* Copyright (C) 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.
	*/

	//#define LOG_NDEBUG 0
	#define LOG_TAG "audio_utils_fifo"

	#include <limits.h>
	#include <stdlib.h>
	#include <string.h>
	#include <audio_utils/fifo.h>
	#include <audio_utils/roundup.h>
	#include <cutils/log.h>
	#include <utils/Errors.h>

	audio_utils_fifo_base::audio_utils_fifo_base(uint32_t frameCount)
	__attribute__((no_sanitize("integer"))) :
	mFrameCount(frameCount), mFrameCountP2(roundup(frameCount)),
	mFudgeFactor(mFrameCountP2 - mFrameCount),
	mSharedRear(0), mThrottleFront(NULL)
	{
	// actual upper bound on frameCount will depend on the frame size
	LOG_ALWAYS_FATAL_IF(frameCount == 0 \|\| frameCount > ((uint32_t) INT_MAX));
	}

	audio_utils_fifo_base::~audio_utils_fifo_base()
	{
	}

	uint32_t audio_utils_fifo_base::sum(uint32_t index, uint32_t increment)
	__attribute__((no_sanitize("integer")))
	{
	if (mFudgeFactor) {
	uint32_t mask = mFrameCountP2 - 1;
	ALOG_ASSERT((index & mask) < mFrameCount);
	ALOG_ASSERT(increment <= mFrameCountP2);
	if ((index & mask) + increment >= mFrameCount) {
	increment += mFudgeFactor;
	}
	index += increment;
	ALOG_ASSERT((index & mask) < mFrameCount);
	return index;
	} else {
	return index + increment;
	}
	}

	int32_t audio_utils_fifo_base::diff(uint32_t rear, uint32_t front, size_t *lost)
	__attribute__((no_sanitize("integer")))
	{
	uint32_t diff = rear - front;
	if (mFudgeFactor) {
	uint32_t mask = mFrameCountP2 - 1;
	uint32_t rearMasked = rear & mask;
	uint32_t frontMasked = front & mask;
	if (rearMasked >= mFrameCount \|\| frontMasked >= mFrameCount) {
	return -EIO;
	}
	uint32_t genDiff = (rear & ~mask) - (front & ~mask);
	if (genDiff != 0) {
	if (genDiff > mFrameCountP2) {
	if (lost != NULL) {
	// TODO provide a more accurate estimate
	lost = (genDiff / mFrameCountP2) mFrameCount;
	}
	return -EOVERFLOW;
	}
	diff -= mFudgeFactor;
	}
	}
	// FIFO should not be overfull
	if (diff > mFrameCount) {
	if (lost != NULL) {
	*lost = diff - mFrameCount;
	}
	return -EOVERFLOW;
	}
	return (int32_t) diff;
	}

	////////////////////////////////////////////////////////////////////////////////

	audio_utils_fifo::audio_utils_fifo(uint32_t frameCount, uint32_t frameSize, void *buffer)
	__attribute__((no_sanitize("integer"))) :
	audio_utils_fifo_base(frameCount), mFrameSize(frameSize), mBuffer(buffer)
	{
	// maximum value of frameCount * frameSize is INT_MAX (2^31 - 1), not 2^31, because we need to
	// be able to distinguish successful and error return values from read and write.
	LOG_ALWAYS_FATAL_IF(frameCount == 0 \|\| frameSize == 0 \|\| buffer == NULL \|\|
	frameCount > ((uint32_t) INT_MAX) / frameSize);
	}

	audio_utils_fifo::~audio_utils_fifo()
	{
	}

	////////////////////////////////////////////////////////////////////////////////

	audio_utils_fifo_provider::audio_utils_fifo_provider() :
	mObtained(0)
	{
	}

	audio_utils_fifo_provider::~audio_utils_fifo_provider()
	{
	}

	////////////////////////////////////////////////////////////////////////////////

	audio_utils_fifo_writer::audio_utils_fifo_writer(audio_utils_fifo& fifo) :
	audio_utils_fifo_provider(), mFifo(fifo), mLocalRear(0)
	{
	}

	audio_utils_fifo_writer::~audio_utils_fifo_writer()
	{
	}

	ssize_t audio_utils_fifo_writer::write(const void *buffer, size_t count)
	__attribute__((no_sanitize("integer")))
	{
	audio_utils_iovec iovec[2];
	ssize_t availToWrite = obtain(iovec, count);
	if (availToWrite > 0) {
	memcpy((char ) mFifo.mBuffer + iovec[0].mOffset mFifo.mFrameSize, buffer,
	iovec[0].mLength * mFifo.mFrameSize);
	if (iovec[1].mLength > 0) {
	memcpy((char ) mFifo.mBuffer + iovec[1].mOffset mFifo.mFrameSize,
	(char ) buffer + (iovec[0].mLength mFifo.mFrameSize),
	iovec[1].mLength * mFifo.mFrameSize);
	}
	release(availToWrite);
	}
	return availToWrite;
	}

	ssize_t audio_utils_fifo_writer::obtain(audio_utils_iovec iovec[2], size_t count)
	__attribute__((no_sanitize("integer")))
	{
	size_t availToWrite;
	if (mFifo.mThrottleFront != NULL) {
	uint32_t front = (uint32_t) atomic_load_explicit(mFifo.mThrottleFront,
	std::memory_order_acquire);
	int32_t filled = mFifo.diff(mLocalRear, front, NULL /lost/);
	if (filled < 0) {
	mObtained = 0;
	return (ssize_t) filled;
	}
	availToWrite = (size_t) mFifo.mFrameCount - (size_t) filled;
	} else {
	availToWrite = mFifo.mFrameCount;
	}
	if (availToWrite > count) {
	availToWrite = count;
	}
	uint32_t rearMasked = mLocalRear & (mFifo.mFrameCountP2 - 1);
	size_t part1 = mFifo.mFrameCount - rearMasked;
	if (part1 > availToWrite) {
	part1 = availToWrite;
	}
	size_t part2 = part1 > 0 ? availToWrite - part1 : 0;
	iovec[0].mOffset = rearMasked;
	iovec[0].mLength = part1;
	iovec[1].mOffset = 0;
	iovec[1].mLength = part2;
	mObtained = availToWrite;
	return availToWrite;
	}

	void audio_utils_fifo_writer::release(size_t count)
	__attribute__((no_sanitize("integer")))
	{
	if (count > 0) {
	LOG_ALWAYS_FATAL_IF(count > mObtained);
	mLocalRear = mFifo.sum(mLocalRear, count);
	atomic_store_explicit(&mFifo.mSharedRear, (uint_fast32_t) mLocalRear,
	std::memory_order_release);
	mObtained -= count;
	}
	}

	////////////////////////////////////////////////////////////////////////////////

	audio_utils_fifo_reader::audio_utils_fifo_reader(audio_utils_fifo& fifo, bool throttlesWriter) :
	audio_utils_fifo_provider(), mFifo(fifo), mLocalFront(0), mSharedFront(0)
	{
	if (throttlesWriter) {
	LOG_ALWAYS_FATAL_IF(fifo.mThrottleFront != NULL);
	fifo.mThrottleFront = &mSharedFront;
	}
	}

	audio_utils_fifo_reader::~audio_utils_fifo_reader()
	{
	// TODO Need a way to pass throttle capability to the another reader, should one reader exit.
	if (mFifo.mThrottleFront == &mSharedFront) {
	mFifo.mThrottleFront = NULL;
	}
	}

	ssize_t audio_utils_fifo_reader::read(void buffer, size_t count, size_t lost)
	__attribute__((no_sanitize("integer")))
	{
	audio_utils_iovec iovec[2];
	ssize_t availToRead = obtain(iovec, count, lost);
	if (availToRead > 0) {
	memcpy(buffer, (char ) mFifo.mBuffer + iovec[0].mOffset mFifo.mFrameSize,
	iovec[0].mLength * mFifo.mFrameSize);
	if (iovec[1].mLength > 0) {
	memcpy((char ) buffer + (iovec[0].mLength mFifo.mFrameSize),
	(char ) mFifo.mBuffer + iovec[1].mOffset mFifo.mFrameSize,
	iovec[1].mLength * mFifo.mFrameSize);
	}
	release(availToRead);
	}
	return availToRead;
	}

	ssize_t audio_utils_fifo_reader::obtain(audio_utils_iovec iovec[2], size_t count)
	__attribute__((no_sanitize("integer")))
	{
	return obtain(iovec, count, NULL);
	}

	void audio_utils_fifo_reader::release(size_t count)
	__attribute__((no_sanitize("integer")))
	{
	if (count > 0) {
	LOG_ALWAYS_FATAL_IF(count > mObtained);
	mLocalFront = mFifo.sum(mLocalFront, count);
	if (mFifo.mThrottleFront == &mSharedFront) {
	atomic_store_explicit(&mSharedFront, (uint_fast32_t) mLocalFront,
	std::memory_order_release);
	}
	mObtained -= count;
	}
	}

	ssize_t audio_utils_fifo_reader::obtain(audio_utils_iovec iovec[2], size_t count, size_t *lost)
	__attribute__((no_sanitize("integer")))
	{
	uint32_t rear = (uint32_t) atomic_load_explicit(&mFifo.mSharedRear,
	std::memory_order_acquire);
	int32_t filled = mFifo.diff(rear, mLocalFront, lost);
	if (filled < 0) {
	if (filled == android::BAD_INDEX) {
	mLocalFront = rear;
	}
	mObtained = 0;
	return (ssize_t) filled;
	}
	size_t availToRead = (size_t) filled;
	if (availToRead > count) {
	availToRead = count;
	}
	uint32_t frontMasked = mLocalFront & (mFifo.mFrameCountP2 - 1);
	size_t part1 = mFifo.mFrameCount - frontMasked;
	if (part1 > availToRead) {
	part1 = availToRead;
	}
	size_t part2 = part1 > 0 ? availToRead - part1 : 0;
	iovec[0].mOffset = frontMasked;
	iovec[0].mLength = part1;
	iovec[1].mOffset = 0;
	iovec[1].mLength = part2;
	mObtained = availToRead;
	return availToRead;
	}