1 files changed, 64 insertions, 0 deletions
diff --git a/include/media/nbaio/Pipe.h b/include/media/nbaio/Pipe.h
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+++ b/include/media/nbaio/Pipe.h
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+/*
+ * 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.
+ */
+
+#ifndef ANDROID_AUDIO_PIPE_H
+#define ANDROID_AUDIO_PIPE_H
+
+#include "NBAIO.h"
+
+namespace android {
+
+// Pipe is multi-thread safe for readers (see PipeReader), but safe for only a single writer thread.
+// It cannot UNDERRUN on write, unless we allow designation of a master reader that provides the
+// time-base. Readers can be added and removed dynamically, and it's OK to have no readers.
+class Pipe : public NBAIO_Sink {
+
+    friend class PipeReader;
+
+public:
+    // maxFrames will be rounded up to a power of 2, and all slots are available. Must be >= 2.
+    Pipe(size_t maxFrames, NBAIO_Format format);
+    virtual ~Pipe();
+
+    // NBAIO_Port interface
+
+    //virtual ssize_t negotiate(const NBAIO_Format offers[], size_t numOffers,
+    //                          NBAIO_Format counterOffers[], size_t& numCounterOffers);
+    //virtual NBAIO_Format format() const;
+
+    // NBAIO_Sink interface
+
+    //virtual size_t framesWritten() const;
+    //virtual size_t framesUnderrun() const;
+    //virtual size_t underruns() const;
+
+    // The write side of a pipe permits overruns; flow control is the caller's responsibility.
+    // It doesn't return +infinity because that would guarantee an overrun.
+    virtual ssize_t availableToWrite() const { return mMaxFrames; }
+
+    virtual ssize_t write(const void *buffer, size_t count);
+    //virtual ssize_t writeVia(writeVia_t via, size_t total, void *user, size_t block);
+
+private:
+    const size_t    mMaxFrames;     // always a power of 2
+    void * const    mBuffer;
+    volatile int32_t mRear;         // written by android_atomic_release_store
+    volatile int32_t mReaders;      // number of PipeReader clients currently attached to this Pipe
+};
+
+}   // namespace android
+
+#endif  // ANDROID_AUDIO_PIPE_H