io_cache.h

// Copyright 2015 Google Inc. All rights reserved.
//
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file or at
// https://developers.google.com/open-source/licenses/bsd

#ifndef PACKAGER_FILE_IO_CACHE_H_
#define PACKAGER_FILE_IO_CACHE_H_

#include <stdint.h>
#include <vector>
#include "packager/base/macros.h"
#include "packager/base/synchronization/lock.h"
#include "packager/base/synchronization/waitable_event.h"

namespace edash_packager {
namespace media {

class IoCache {
 public:
  explicit IoCache(uint64_t cache_size);
  ~IoCache();

  uint64_t Read(void* buffer, uint64_t size);

  uint64_t Write(const void* buffer, uint64_t size);

  void Clear();

  void Close();

  uint64_t BytesCached();

  uint64_t BytesFree();

  void WaitUntilEmptyOrClosed();

 private:
  uint64_t BytesCachedInternal();
  uint64_t BytesFreeInternal();

  const uint64_t cache_size_;
  base::Lock lock_;
  base::WaitableEvent read_event_;
  base::WaitableEvent write_event_;
  std::vector<uint8_t> circular_buffer_;
  const uint8_t* end_ptr_;
  uint8_t* r_ptr_;
  uint8_t* w_ptr_;
  bool closed_;

  DISALLOW_COPY_AND_ASSIGN(IoCache);
};

}  // namespace media
}  // namespace edash_packager

#endif  // PACKAGER_FILE_IO_CACHE_H