bin/media/audio_core/utils.h

// Copyright 2017 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef GARNET_BIN_MEDIA_AUDIO_CORE_UTILS_H_
#define GARNET_BIN_MEDIA_AUDIO_CORE_UTILS_H_

#include <fbl/ref_counted.h>
#include <fuchsia/media/cpp/fidl.h>
#include <lib/fzl/vmo-mapper.h>
#include <stdint.h>
#include <zircon/device/audio.h>
#include <zircon/types.h>
#include <atomic>
#include <vector>

#include "garnet/bin/media/audio_core/mixer/constants.h"

namespace media {
namespace audio {

class GenerationId {
 public:
  uint32_t get() const { return id_; }
  uint32_t Next() {
    uint32_t ret;
    do {
      ret = ++id_;
    } while (ret == kInvalidGenerationId);
    return ret;
  }

 private:
  uint32_t id_ = kInvalidGenerationId + 1;
};

class AtomicGenerationId {
 public:
  AtomicGenerationId() : id_(kInvalidGenerationId + 1) {}

  uint32_t get() const { return id_.load(); }
  uint32_t Next() {
    uint32_t ret;
    do {
      ret = id_.fetch_add(1);
    } while (ret == kInvalidGenerationId);
    return ret;
  }

 private:
  std::atomic<uint32_t> id_;
};

// Given a preferred format and a list of driver supported format ranges, select
// the "best" form and update the in/out parameters, then return ZX_OK.  If no
// formats exist, or all format ranges get completely rejected, return an error
// and leave the in/out params as they were.
zx_status_t SelectBestFormat(
    const std::vector<audio_stream_format_range_t>& fmts,
    uint32_t* frames_per_second_inout, uint32_t* channels_inout,
    fuchsia::media::AudioSampleFormat* sample_format_inout);

// A simple extension to the libfzl VmoMapper which mixes in ref counting state
// to allow for shared VmoMapper semantics.
class RefCountedVmoMapper : public fzl::VmoMapper,
                            public fbl::RefCounted<fzl::VmoMapper> {
 public:
  RefCountedVmoMapper() = default;
};

}  // namespace audio
}  // namespace media

#endif  // GARNET_BIN_MEDIA_AUDIO_CORE_UTILS_H_