fifo.cpp revision 9b4c805bc22842480690f14826b729845887963a
19b4c805bc22842480690f14826b729845887963aGlenn Kasten/* 29b4c805bc22842480690f14826b729845887963aGlenn Kasten * Copyright (C) 2015 The Android Open Source Project 39b4c805bc22842480690f14826b729845887963aGlenn Kasten * 49b4c805bc22842480690f14826b729845887963aGlenn Kasten * Licensed under the Apache License, Version 2.0 (the "License"); 59b4c805bc22842480690f14826b729845887963aGlenn Kasten * you may not use this file except in compliance with the License. 69b4c805bc22842480690f14826b729845887963aGlenn Kasten * You may obtain a copy of the License at 79b4c805bc22842480690f14826b729845887963aGlenn Kasten * 89b4c805bc22842480690f14826b729845887963aGlenn Kasten * http://www.apache.org/licenses/LICENSE-2.0 99b4c805bc22842480690f14826b729845887963aGlenn Kasten * 109b4c805bc22842480690f14826b729845887963aGlenn Kasten * Unless required by applicable law or agreed to in writing, software 119b4c805bc22842480690f14826b729845887963aGlenn Kasten * distributed under the License is distributed on an "AS IS" BASIS, 129b4c805bc22842480690f14826b729845887963aGlenn Kasten * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 139b4c805bc22842480690f14826b729845887963aGlenn Kasten * See the License for the specific language governing permissions and 149b4c805bc22842480690f14826b729845887963aGlenn Kasten * limitations under the License. 159b4c805bc22842480690f14826b729845887963aGlenn Kasten */ 169b4c805bc22842480690f14826b729845887963aGlenn Kasten 179b4c805bc22842480690f14826b729845887963aGlenn Kasten//#define LOG_NDEBUG 0 189b4c805bc22842480690f14826b729845887963aGlenn Kasten#define LOG_TAG "audio_utils_fifo" 199b4c805bc22842480690f14826b729845887963aGlenn Kasten 209b4c805bc22842480690f14826b729845887963aGlenn Kasten#include <stdlib.h> 219b4c805bc22842480690f14826b729845887963aGlenn Kasten#include <string.h> 229b4c805bc22842480690f14826b729845887963aGlenn Kasten#include <audio_utils/fifo.h> 239b4c805bc22842480690f14826b729845887963aGlenn Kasten#include <audio_utils/roundup.h> 249b4c805bc22842480690f14826b729845887963aGlenn Kasten#include <cutils/atomic.h> 259b4c805bc22842480690f14826b729845887963aGlenn Kasten#include <cutils/log.h> 269b4c805bc22842480690f14826b729845887963aGlenn Kasten 279b4c805bc22842480690f14826b729845887963aGlenn Kastenvoid audio_utils_fifo_init(struct audio_utils_fifo *fifo, size_t frameCount, size_t frameSize, 289b4c805bc22842480690f14826b729845887963aGlenn Kasten void *buffer) 299b4c805bc22842480690f14826b729845887963aGlenn Kasten{ 309b4c805bc22842480690f14826b729845887963aGlenn Kasten // We would need a 64-bit roundup to support larger frameCount. 319b4c805bc22842480690f14826b729845887963aGlenn Kasten ALOG_ASSERT(fifo != NULL && frameCount > 0 && frameSize > 0 && buffer != NULL); 329b4c805bc22842480690f14826b729845887963aGlenn Kasten fifo->mFrameCount = frameCount; 339b4c805bc22842480690f14826b729845887963aGlenn Kasten fifo->mFrameCountP2 = roundup(frameCount); 349b4c805bc22842480690f14826b729845887963aGlenn Kasten fifo->mFudgeFactor = fifo->mFrameCountP2 - fifo->mFrameCount; 359b4c805bc22842480690f14826b729845887963aGlenn Kasten fifo->mFrameSize = frameSize; 369b4c805bc22842480690f14826b729845887963aGlenn Kasten fifo->mBuffer = buffer; 379b4c805bc22842480690f14826b729845887963aGlenn Kasten fifo->mFront = 0; 389b4c805bc22842480690f14826b729845887963aGlenn Kasten fifo->mRear = 0; 399b4c805bc22842480690f14826b729845887963aGlenn Kasten} 409b4c805bc22842480690f14826b729845887963aGlenn Kasten 419b4c805bc22842480690f14826b729845887963aGlenn Kastenvoid audio_utils_fifo_deinit(struct audio_utils_fifo *fifo __unused) 429b4c805bc22842480690f14826b729845887963aGlenn Kasten{ 439b4c805bc22842480690f14826b729845887963aGlenn Kasten} 449b4c805bc22842480690f14826b729845887963aGlenn Kasten 459b4c805bc22842480690f14826b729845887963aGlenn Kasten// Return a new index as the sum of an old index (either mFront or mRear) and a specified increment. 469b4c805bc22842480690f14826b729845887963aGlenn Kastenstatic inline int32_t audio_utils_fifo_sum(struct audio_utils_fifo *fifo, int32_t index, 479b4c805bc22842480690f14826b729845887963aGlenn Kasten uint32_t increment) 489b4c805bc22842480690f14826b729845887963aGlenn Kasten{ 499b4c805bc22842480690f14826b729845887963aGlenn Kasten if (fifo->mFudgeFactor) { 509b4c805bc22842480690f14826b729845887963aGlenn Kasten uint32_t mask = fifo->mFrameCountP2 - 1; 519b4c805bc22842480690f14826b729845887963aGlenn Kasten ALOG_ASSERT((index & mask) < fifo->mFrameCount); 529b4c805bc22842480690f14826b729845887963aGlenn Kasten ALOG_ASSERT(/*0 <= increment &&*/ increment <= fifo->mFrameCountP2); 539b4c805bc22842480690f14826b729845887963aGlenn Kasten if ((index & mask) + increment >= fifo->mFrameCount) { 549b4c805bc22842480690f14826b729845887963aGlenn Kasten increment += fifo->mFudgeFactor; 559b4c805bc22842480690f14826b729845887963aGlenn Kasten } 569b4c805bc22842480690f14826b729845887963aGlenn Kasten index += increment; 579b4c805bc22842480690f14826b729845887963aGlenn Kasten ALOG_ASSERT((index & mask) < fifo->mFrameCount); 589b4c805bc22842480690f14826b729845887963aGlenn Kasten return index; 599b4c805bc22842480690f14826b729845887963aGlenn Kasten } else { 609b4c805bc22842480690f14826b729845887963aGlenn Kasten return index + increment; 619b4c805bc22842480690f14826b729845887963aGlenn Kasten } 629b4c805bc22842480690f14826b729845887963aGlenn Kasten} 639b4c805bc22842480690f14826b729845887963aGlenn Kasten 649b4c805bc22842480690f14826b729845887963aGlenn Kasten// Return the difference between two indices: rear - front, where 0 <= difference <= mFrameCount. 659b4c805bc22842480690f14826b729845887963aGlenn Kastenstatic inline size_t audio_utils_fifo_diff(struct audio_utils_fifo *fifo, int32_t rear, 669b4c805bc22842480690f14826b729845887963aGlenn Kasten int32_t front) 679b4c805bc22842480690f14826b729845887963aGlenn Kasten{ 689b4c805bc22842480690f14826b729845887963aGlenn Kasten int32_t diff = rear - front; 699b4c805bc22842480690f14826b729845887963aGlenn Kasten if (fifo->mFudgeFactor) { 709b4c805bc22842480690f14826b729845887963aGlenn Kasten uint32_t mask = ~(fifo->mFrameCountP2 - 1); 719b4c805bc22842480690f14826b729845887963aGlenn Kasten int32_t genDiff = (rear & mask) - (front & mask); 729b4c805bc22842480690f14826b729845887963aGlenn Kasten if (genDiff != 0) { 739b4c805bc22842480690f14826b729845887963aGlenn Kasten ALOG_ASSERT(genDiff == (int32_t) fifo->mFrameCountP2); 749b4c805bc22842480690f14826b729845887963aGlenn Kasten diff -= fifo->mFudgeFactor; 759b4c805bc22842480690f14826b729845887963aGlenn Kasten } 769b4c805bc22842480690f14826b729845887963aGlenn Kasten } 779b4c805bc22842480690f14826b729845887963aGlenn Kasten // FIFO should not be overfull 789b4c805bc22842480690f14826b729845887963aGlenn Kasten ALOG_ASSERT(0 <= diff && diff <= (int32_t) fifo->mFrameCount); 799b4c805bc22842480690f14826b729845887963aGlenn Kasten return (size_t) diff; 809b4c805bc22842480690f14826b729845887963aGlenn Kasten} 819b4c805bc22842480690f14826b729845887963aGlenn Kasten 829b4c805bc22842480690f14826b729845887963aGlenn Kastenssize_t audio_utils_fifo_write(struct audio_utils_fifo *fifo, const void *buffer, size_t count) 839b4c805bc22842480690f14826b729845887963aGlenn Kasten{ 849b4c805bc22842480690f14826b729845887963aGlenn Kasten int32_t front = android_atomic_acquire_load(&fifo->mFront); 859b4c805bc22842480690f14826b729845887963aGlenn Kasten int32_t rear = fifo->mRear; 869b4c805bc22842480690f14826b729845887963aGlenn Kasten size_t availToWrite = fifo->mFrameCount - audio_utils_fifo_diff(fifo, rear, front); 879b4c805bc22842480690f14826b729845887963aGlenn Kasten if (availToWrite > count) { 889b4c805bc22842480690f14826b729845887963aGlenn Kasten availToWrite = count; 899b4c805bc22842480690f14826b729845887963aGlenn Kasten } 909b4c805bc22842480690f14826b729845887963aGlenn Kasten rear &= fifo->mFrameCountP2 - 1; 919b4c805bc22842480690f14826b729845887963aGlenn Kasten size_t part1 = fifo->mFrameCount - rear; 929b4c805bc22842480690f14826b729845887963aGlenn Kasten if (part1 > availToWrite) { 939b4c805bc22842480690f14826b729845887963aGlenn Kasten part1 = availToWrite; 949b4c805bc22842480690f14826b729845887963aGlenn Kasten } 959b4c805bc22842480690f14826b729845887963aGlenn Kasten if (part1 > 0) { 969b4c805bc22842480690f14826b729845887963aGlenn Kasten memcpy((char *) fifo->mBuffer + (rear * fifo->mFrameSize), buffer, 979b4c805bc22842480690f14826b729845887963aGlenn Kasten part1 * fifo->mFrameSize); 989b4c805bc22842480690f14826b729845887963aGlenn Kasten size_t part2 = availToWrite - part1; 999b4c805bc22842480690f14826b729845887963aGlenn Kasten if (part2 > 0) { 1009b4c805bc22842480690f14826b729845887963aGlenn Kasten memcpy(fifo->mBuffer, (char *) buffer + (part1 * fifo->mFrameSize), 1019b4c805bc22842480690f14826b729845887963aGlenn Kasten part2 * fifo->mFrameSize); 1029b4c805bc22842480690f14826b729845887963aGlenn Kasten } 1039b4c805bc22842480690f14826b729845887963aGlenn Kasten android_atomic_release_store(audio_utils_fifo_sum(fifo, fifo->mRear, availToWrite), 1049b4c805bc22842480690f14826b729845887963aGlenn Kasten &fifo->mRear); 1059b4c805bc22842480690f14826b729845887963aGlenn Kasten } 1069b4c805bc22842480690f14826b729845887963aGlenn Kasten return availToWrite; 1079b4c805bc22842480690f14826b729845887963aGlenn Kasten} 1089b4c805bc22842480690f14826b729845887963aGlenn Kasten 1099b4c805bc22842480690f14826b729845887963aGlenn Kastenssize_t audio_utils_fifo_read(struct audio_utils_fifo *fifo, void *buffer, size_t count) 1109b4c805bc22842480690f14826b729845887963aGlenn Kasten{ 1119b4c805bc22842480690f14826b729845887963aGlenn Kasten int32_t rear = android_atomic_acquire_load(&fifo->mRear); 1129b4c805bc22842480690f14826b729845887963aGlenn Kasten int32_t front = fifo->mFront; 1139b4c805bc22842480690f14826b729845887963aGlenn Kasten size_t availToRead = audio_utils_fifo_diff(fifo, rear, front); 1149b4c805bc22842480690f14826b729845887963aGlenn Kasten if (availToRead > count) { 1159b4c805bc22842480690f14826b729845887963aGlenn Kasten availToRead = count; 1169b4c805bc22842480690f14826b729845887963aGlenn Kasten } 1179b4c805bc22842480690f14826b729845887963aGlenn Kasten front &= fifo->mFrameCountP2 - 1; 1189b4c805bc22842480690f14826b729845887963aGlenn Kasten size_t part1 = fifo->mFrameCount - front; 1199b4c805bc22842480690f14826b729845887963aGlenn Kasten if (part1 > availToRead) { 1209b4c805bc22842480690f14826b729845887963aGlenn Kasten part1 = availToRead; 1219b4c805bc22842480690f14826b729845887963aGlenn Kasten } 1229b4c805bc22842480690f14826b729845887963aGlenn Kasten if (part1 > 0) { 1239b4c805bc22842480690f14826b729845887963aGlenn Kasten memcpy(buffer, (char *) fifo->mBuffer + (front * fifo->mFrameSize), 1249b4c805bc22842480690f14826b729845887963aGlenn Kasten part1 * fifo->mFrameSize); 1259b4c805bc22842480690f14826b729845887963aGlenn Kasten size_t part2 = availToRead - part1; 1269b4c805bc22842480690f14826b729845887963aGlenn Kasten if (part2 > 0) { 1279b4c805bc22842480690f14826b729845887963aGlenn Kasten memcpy((char *) buffer + (part1 * fifo->mFrameSize), fifo->mBuffer, 1289b4c805bc22842480690f14826b729845887963aGlenn Kasten part2 * fifo->mFrameSize); 1299b4c805bc22842480690f14826b729845887963aGlenn Kasten } 1309b4c805bc22842480690f14826b729845887963aGlenn Kasten android_atomic_release_store(audio_utils_fifo_sum(fifo, fifo->mFront, availToRead), 1319b4c805bc22842480690f14826b729845887963aGlenn Kasten &fifo->mFront); 1329b4c805bc22842480690f14826b729845887963aGlenn Kasten } 1339b4c805bc22842480690f14826b729845887963aGlenn Kasten return availToRead; 1349b4c805bc22842480690f14826b729845887963aGlenn Kasten} 135