include/singa/io/kvfile_store.h

/************************************************************
*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements.  See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership.  The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
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#ifndef SINGA_IO_KVFILE_STORE_H_
#define SINGA_IO_KVFILE_STORE_H_

#include <string>
#include "singa/io/store.h"
#include "singa/io/kvfile.h"

namespace singa {
namespace io {

/**
 * Use the KVFile as the data storage.
 *
 * KVFile is a binary file. Each tuple is stored as byte string.
 */
class KVFileStore : public Store {
 public:
  ~KVFileStore() { Close();}
  bool Open(const std::string& source, Mode mode) override;
  void Close() override;
  bool Read(std::string* key, std::string* value) override;
  void SeekToFirst() override;
  void Seek(int offset) override;
  bool Write(const std::string& key, const std::string& value) override;
  void Flush() override;

 private:
  KVFile* file_ = nullptr;
  Mode mode_;
};

}  // namespace io
}  // namespace singa

#endif  // SINGA_IO_KVFILE_STORE_H_