| /* |
| * 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 "Pipe" |
| //#define LOG_NDEBUG 0 |
| |
| #include <cutils/atomic.h> |
| #include <cutils/compiler.h> |
| #include <utils/Log.h> |
| #include <media/nbaio/Pipe.h> |
| #include <audio_utils/roundup.h> |
| |
| namespace android { |
| |
| Pipe::Pipe(size_t maxFrames, const NBAIO_Format& format, void *buffer) : |
| NBAIO_Sink(format), |
| mMaxFrames(roundup(maxFrames)), |
| mBuffer(buffer == NULL ? malloc(mMaxFrames * Format_frameSize(format)) : buffer), |
| mRear(0), |
| mReaders(0), |
| mFreeBufferInDestructor(buffer == NULL) |
| { |
| } |
| |
| Pipe::~Pipe() |
| { |
| ALOG_ASSERT(android_atomic_acquire_load(&mReaders) == 0); |
| if (mFreeBufferInDestructor) { |
| free(mBuffer); |
| } |
| } |
| |
| ssize_t Pipe::write(const void *buffer, size_t count) |
| { |
| // count == 0 is unlikely and not worth checking for |
| if (CC_UNLIKELY(!mNegotiated)) { |
| return NEGOTIATE; |
| } |
| // write() is not multi-thread safe w.r.t. itself, so no mutex or atomic op needed to read mRear |
| size_t rear = mRear & (mMaxFrames - 1); |
| size_t written = mMaxFrames - rear; |
| if (CC_LIKELY(written > count)) { |
| written = count; |
| } |
| memcpy((char *) mBuffer + (rear * mFrameSize), buffer, written * mFrameSize); |
| if (CC_UNLIKELY(rear + written == mMaxFrames)) { |
| if (CC_UNLIKELY((count -= written) > rear)) { |
| count = rear; |
| } |
| if (CC_LIKELY(count > 0)) { |
| memcpy(mBuffer, (char *) buffer + (written * mFrameSize), count * mFrameSize); |
| written += count; |
| } |
| } |
| android_atomic_release_store(written + mRear, &mRear); |
| mFramesWritten += written; |
| return written; |
| } |
| |
| } // namespace android |