/*
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* Copyright (C) 2016 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef ANDROID_AUDIO_MMAP_STREAM_INTERFACE_H
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#define ANDROID_AUDIO_MMAP_STREAM_INTERFACE_H
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#include <system/audio.h>
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#include <media/AudioClient.h>
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#include <utils/Errors.h>
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#include <utils/RefBase.h>
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namespace android {
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class MmapStreamCallback;
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class MmapStreamInterface : public virtual RefBase
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{
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public:
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/**
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* Values for direction argument passed to openMmapStream()
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*/
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typedef enum {
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DIRECTION_OUTPUT = 0, /**< open a playback mmap stream */
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DIRECTION_INPUT, /**< open a capture mmap stream */
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} stream_direction_t;
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/**
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* Open a playback or capture stream in MMAP mode at the audio HAL.
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*
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* \note This method is implemented by AudioFlinger
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*
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* \param[in] direction open a playback or capture stream.
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* \param[in] attr audio attributes defining the main use case for this stream
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* \param[in,out] config audio parameters (sampling rate, format ...) for the stream.
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* Requested parameters as input,
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* Actual parameters as output
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* \param[in] client a AudioClient struct describing the first client using this stream.
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* \param[in,out] deviceId audio device the stream should preferably be routed to/from
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* Requested as input,
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* Actual as output
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* \param[in,out] sessionId audio sessionId for the stream
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* Requested as input, may be AUDIO_SESSION_ALLOCATE
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* Actual as output
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* \param[in] callback the MmapStreamCallback interface used by AudioFlinger to notify
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* condition changes affecting the stream operation
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* \param[out] interface the MmapStreamInterface interface controlling the created stream
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* \param[out] same unique handle as the one used for the first client stream started.
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* \return OK if the stream was successfully created.
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* NO_INIT if AudioFlinger is not properly initialized
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* BAD_VALUE if the stream cannot be opened because of invalid arguments
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* INVALID_OPERATION if the stream cannot be opened because of platform limitations
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*/
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static status_t openMmapStream(stream_direction_t direction,
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const audio_attributes_t *attr,
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audio_config_base_t *config,
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const AudioClient& client,
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audio_port_handle_t *deviceId,
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audio_session_t *sessionId,
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const sp<MmapStreamCallback>& callback,
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sp<MmapStreamInterface>& interface,
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audio_port_handle_t *handle);
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/**
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* Retrieve information on the mmap buffer used for audio samples transfer.
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* Must be called before any other method after opening the stream or entering standby.
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*
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* \param[in] min_size_frames minimum buffer size requested. The actual buffer
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* size returned in struct audio_mmap_buffer_info can be larger.
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* \param[out] info address at which the mmap buffer information should be returned.
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*
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* \return OK if the buffer was allocated.
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* NO_INIT in case of initialization error
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* BAD_VALUE if the requested buffer size is too large
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* INVALID_OPERATION if called out of sequence (e.g. buffer already allocated)
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*/
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virtual status_t createMmapBuffer(int32_t minSizeFrames,
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struct audio_mmap_buffer_info *info) = 0;
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/**
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* Read current read/write position in the mmap buffer with associated time stamp.
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*
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* \param[out] position address at which the mmap read/write position should be returned.
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*
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* \return OK if the position is successfully returned.
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* NO_INIT in case of initialization error
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* NOT_ENOUGH_DATA if the position cannot be retrieved
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* INVALID_OPERATION if called before createMmapBuffer()
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*/
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virtual status_t getMmapPosition(struct audio_mmap_position *position) = 0;
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/**
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* Start a stream operating in mmap mode.
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* createMmapBuffer() must be called before calling start()
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*
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* \param[in] client a AudioClient struct describing the client starting on this stream.
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* \param[out] handle unique handle for this instance. Used with stop().
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* \return OK in case of success.
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* NO_INIT in case of initialization error
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* INVALID_OPERATION if called out of sequence
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*/
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virtual status_t start(const AudioClient& client, audio_port_handle_t *handle) = 0;
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/**
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* Stop a stream operating in mmap mode.
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* Must be called after start()
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*
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* \param[in] handle unique handle allocated by start().
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* \return OK in case of success.
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* NO_INIT in case of initialization error
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* INVALID_OPERATION if called out of sequence
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*/
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virtual status_t stop(audio_port_handle_t handle) = 0;
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/**
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* Put a stream operating in mmap mode into standby.
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* Must be called after createMmapBuffer(). Cannot be called if any client is active.
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* It is recommended to place a mmap stream into standby as often as possible when no client is
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* active to save power.
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*
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* \return OK in case of success.
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* NO_INIT in case of initialization error
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* INVALID_OPERATION if called out of sequence
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*/
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virtual status_t standby() = 0;
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protected:
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// Subclasses can not be constructed directly by clients.
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MmapStreamInterface() {}
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// The destructor automatically closes the stream.
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virtual ~MmapStreamInterface() {}
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};
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} // namespace android
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#endif // ANDROID_AUDIO_MMAP_STREAM_INTERFACE_H
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