stream_accessor_base.h

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// -*- mode: c++; tab-width: 4; indent-tabs-mode: t; c-file-style: "stroustrup"; -*-
// vi:set ts=4 sts=4 sw=4 noet :
// Copyright 2009, 2010, The TPIE development team
//
// This file is part of TPIE.
//
// TPIE is free software: you can redistribute it and/or modify it under
// the terms of the GNU Lesser General Public License as published by the
// Free Software Foundation, either version 3 of the License, or (at your
// option) any later version.
//
// TPIE is distributed in the hope that it will be useful, but WITHOUT ANY
// WARRANTY; without even the implied warranty of MERCHANTABILITY or
// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
// License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with TPIE.  If not, see <http://www.gnu.org/licenses/>
#ifndef TPIE_FILE_ACCESSOR_STREAM_ACCESSOR_BASE_H
#define TPIE_FILE_ACCESSOR_STREAM_ACCESSOR_BASE_H


#include <tpie/stream_header.h>
#include <tpie/cache_hint.h>

namespace tpie {
namespace file_accessor {

template <typename file_accessor_t>
class stream_accessor_base {
private:
    inline void validate_header(const stream_header_t & header);
    inline void fill_header(stream_header_t & header, bool clean);

    bool m_open;
    bool m_write;

protected:
    file_accessor_t m_fileAccessor;

private:
    stream_size_type m_size;

    memory_size_type m_userDataSize;

    memory_size_type m_maxUserDataSize;

    memory_size_type m_itemSize;

    memory_size_type m_blockSize;

    memory_size_type m_blockItems;

    stream_size_type m_lastBlockReadOffset;

    int m_compressionFlags;

    bool m_useCompression;

    std::string m_path;

    inline void read_header();

    inline void write_header(bool clean);

protected:
    inline memory_size_type boundary() const { return 4096; }

    inline memory_size_type align_to_boundary(memory_size_type z) const { return (z+boundary()-1)/boundary()*boundary(); }

    inline memory_size_type header_size() const { return align_to_boundary(sizeof(stream_header_t)+m_maxUserDataSize); }

    memory_size_type block_size() const { return m_blockSize; }
    memory_size_type block_items() const { return m_blockItems; }
    memory_size_type item_size() const { return m_itemSize; }

    void set_size(stream_size_type s) { m_size = s; }

public:
    inline stream_accessor_base()
        : m_open(false)
        , m_write(false)
    {
    }

    virtual ~stream_accessor_base() {close();}

    inline void open(const std::string & path,
                     bool read,
                     bool write,
                     memory_size_type itemSize,
                     memory_size_type blockSize,
                     memory_size_type maxUserDataSize,
                     cache_hint cacheHint,
                     int compressionFlags);

    inline void close();

    virtual memory_size_type read_block(void * data, stream_size_type blockNumber, memory_size_type itemCount) = 0;

    virtual void write_block(const void * data, stream_size_type blockNumber, memory_size_type itemCount) = 0;

    inline memory_size_type read_user_data(void * data, memory_size_type count);

    inline void write_user_data(const void * data, memory_size_type count);

    static inline memory_size_type memory_usage() {return sizeof(stream_accessor_base);}

    inline stream_size_type size() const {return m_size;}

    inline const std::string & path() const {return m_path;}

    inline memory_size_type user_data_size() const {return m_userDataSize;}

    inline memory_size_type max_user_data_size() const {return m_maxUserDataSize;}

    inline stream_size_type byte_size() const {
        return ((m_size + m_blockItems - 1)/m_blockItems) * m_blockSize + header_size();
    }

    inline void truncate(stream_size_type items);

    void set_last_block_read_offset(stream_size_type n) { m_lastBlockReadOffset = n; }
    stream_size_type get_last_block_read_offset() { return m_lastBlockReadOffset; }

    bool get_compressed() { return m_useCompression; }

    int get_compression_flags() { return m_compressionFlags; }
};

}
}

#include <tpie/file_accessor/stream_accessor_base.inl>
#endif // TPIE_FILE_ACCESSOR_STREAM_ACCESSOR_BASE_H