| /* |
| * Copyright (C) 2012 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_TAG "MonoPipeReader" |
| //#define LOG_NDEBUG 0 |
| |
| #include <cutils/compiler.h> |
| #include <utils/Log.h> |
| #include <media/nbaio/MonoPipeReader.h> |
| |
| namespace android { |
| |
| MonoPipeReader::MonoPipeReader(MonoPipe* pipe) : |
| NBAIO_Source(pipe->mFormat), |
| mPipe(pipe) |
| { |
| } |
| |
| MonoPipeReader::~MonoPipeReader() |
| { |
| } |
| |
| ssize_t MonoPipeReader::availableToRead() |
| { |
| if (CC_UNLIKELY(!mNegotiated)) { |
| return NEGOTIATE; |
| } |
| ssize_t ret = android_atomic_acquire_load(&mPipe->mRear) - mPipe->mFront; |
| ALOG_ASSERT((0 <= ret) && ((size_t) ret <= mPipe->mMaxFrames)); |
| return ret; |
| } |
| |
| ssize_t MonoPipeReader::read(void *buffer, size_t count) |
| { |
| // count == 0 is unlikely and not worth checking for explicitly; will be handled automatically |
| ssize_t red = availableToRead(); |
| if (CC_UNLIKELY(red <= 0)) { |
| return red; |
| } |
| if (CC_LIKELY((size_t) red > count)) { |
| red = count; |
| } |
| size_t front = mPipe->mFront & (mPipe->mMaxFrames - 1); |
| size_t part1 = mPipe->mMaxFrames - front; |
| if (part1 > (size_t) red) { |
| part1 = red; |
| } |
| if (CC_LIKELY(part1 > 0)) { |
| memcpy(buffer, (char *) mPipe->mBuffer + (front * mFrameSize), part1 * mFrameSize); |
| if (CC_UNLIKELY(front + part1 == mPipe->mMaxFrames)) { |
| size_t part2 = red - part1; |
| if (CC_LIKELY(part2 > 0)) { |
| memcpy((char *) buffer + (part1 * mFrameSize), mPipe->mBuffer, part2 * mFrameSize); |
| } |
| } |
| android_atomic_release_store(red + mPipe->mFront, &mPipe->mFront); |
| mFramesRead += red; |
| } |
| return red; |
| } |
| |
| void MonoPipeReader::onTimestamp(const ExtendedTimestamp ×tamp) |
| { |
| mPipe->mTimestampMutator.push(timestamp); |
| } |
| |
| } // namespace android |