file_base_crtp.h

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// -*- mode: c++; tab-width: 4; indent-tabs-mode: t; eval: (progn (c-set-style "stroustrup") (c-set-offset 'innamespace 0)); -*-
// vi:set ts=4 sts=4 sw=4 noet :
// Copyright 2012 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_BASE_CRTP_H__
#define __TPIE_FILE_BASE_CRTP_H__

#include <tpie/types.h>
#include <tpie/tpie.h>
#include <tpie/exception.h>
#include <tpie/memory.h>
#include <tpie/access_type.h>
#include <tpie/cache_hint.h>
#include <tpie/stream_header.h>
#include <tpie/file_accessor/file_accessor.h>
#include <tpie/tempname.h>

namespace tpie {

template <typename child_t>
class file_base_crtp {
public:
    bool is_readable() const throw() {
        return m_canRead;
    }

    bool is_writable() const throw() {
        return m_canWrite;
    }


    static inline memory_size_type block_size(double blockFactor) throw () {
        return static_cast<memory_size_type>(get_block_size() * blockFactor);
    }

    static inline double calculate_block_factor(memory_size_type blockSize) throw () {
        return (double)blockSize / (double)block_size(1.0);
    }

    static inline memory_size_type block_memory_usage(double blockFactor) {
        return block_size(blockFactor);
    }

    memory_size_type block_items() const {
        return m_blockItems;
    }

    memory_size_type block_size() const {
        return m_blockSize;
    }

    template <typename TT>
    void read_user_data(TT & data) throw(stream_exception) {
        assert(m_open);
        if (sizeof(TT) != user_data_size()) throw io_exception("Wrong user data size");
        m_fileAccessor->read_user_data(reinterpret_cast<void*>(&data), sizeof(TT));
    }

    memory_size_type read_user_data(void * data, memory_size_type count) {
        assert(m_open);
        return m_fileAccessor->read_user_data(data, count);
    }

    template <typename TT>
    void write_user_data(const TT & data) throw(stream_exception) {
        assert(m_open);
        if (sizeof(TT) > max_user_data_size()) throw io_exception("Wrong user data size");
        m_fileAccessor->write_user_data(reinterpret_cast<const void*>(&data), sizeof(TT));
    }

    void write_user_data(const void * data, memory_size_type count) {
        assert(m_open);
        m_fileAccessor->write_user_data(data, count);
    }

    memory_size_type user_data_size() const {
        assert(m_open);
        return m_fileAccessor->user_data_size();
    }

    memory_size_type max_user_data_size() const {
        assert(m_open);
        return m_fileAccessor->max_user_data_size();
    }


    inline const std::string & path() const throw() {
        assert(m_open);
        return m_fileAccessor->path();
    }

    inline void open(const std::string & path,
                     access_type accessType=access_read_write,
                     memory_size_type userDataSize=0,
                     cache_hint cacheHint=access_sequential) throw (stream_exception) {
        self().close();
        self().open_inner(path, accessType, userDataSize, cacheHint);
    }

    inline void open(memory_size_type userDataSize=0,
                     cache_hint cacheHint=access_sequential) throw (stream_exception) {
        self().close();
        m_ownedTempFile.reset(tpie_new<temp_file>());
        m_tempFile=m_ownedTempFile.get();
        self().open_inner(m_tempFile->path(), access_read_write, userDataSize, cacheHint);
    }

    inline void open(temp_file & file,
                     access_type accessType=access_read_write,
                     memory_size_type userDataSize=0,
                     cache_hint cacheHint=access_sequential) throw (stream_exception) {
        self().close();
        m_tempFile=&file;
        self().open_inner(m_tempFile->path(), accessType, userDataSize, cacheHint);
    }

    inline void close() throw(stream_exception) {
        if (m_open) m_fileAccessor->close();
        m_open = false;
        m_tempFile = NULL;
        m_ownedTempFile.reset();
    }

    inline bool is_open() const {
        return m_open;
    }

    inline stream_size_type file_size() const throw() {
        return m_size;
    }

protected:
    inline void open_inner(const std::string & path,
                           access_type accessType,
                           memory_size_type userDataSize,
                           cache_hint cacheHint) throw(stream_exception) {
        m_canRead = accessType == access_read || accessType == access_read_write;
        m_canWrite = accessType == access_write || accessType == access_read_write;
        const bool preferCompression = false;
        m_fileAccessor->open(path, m_canRead, m_canWrite, m_itemSize,
                             m_blockSize, userDataSize, cacheHint,
                             preferCompression);
        if (m_fileAccessor->get_compressed()) {
            m_fileAccessor->close();
            throw stream_exception("Tried to open compressed stream as non-compressed");
        }
        m_size = m_fileAccessor->size();
        m_open = true;
    }


    file_base_crtp(memory_size_type itemSize, double blockFactor,
                   file_accessor::file_accessor * fileAccessor);


    template <typename BT>
    void read_block(BT & b, stream_size_type block);
    void get_block_check(stream_size_type block);

    memory_size_type m_blockItems;
    memory_size_type m_blockSize;
    bool m_canRead;
    bool m_canWrite;
    bool m_open;
    memory_size_type m_itemSize;
    file_accessor::file_accessor * m_fileAccessor;
    tpie::unique_ptr<temp_file> m_ownedTempFile;
    temp_file * m_tempFile;
    stream_size_type m_size;

private:
    child_t & self() {return *static_cast<child_t *>(this);}
    const child_t & self() const {return *static_cast<const child_t *>(this);}
};

} // namespace tpie

#endif // __TPIE_FILE_BASE_CRTP_H__