/*************************************************************************** * include/stxxl/bits/io/fileperblock_file.h * * Part of the STXXL. See http://stxxl.sourceforge.net * * Copyright (C) 2008, 2009 Johannes Singler <singler@ira.uka.de> * * Distributed under the Boost Software License, Version 1.0. * (See accompanying file LICENSE_1_0.txt or copy at * http://www.boost.org/LICENSE_1_0.txt) **************************************************************************/ #ifndef STXXL_FILEPERBLOCK_FILE_HEADER #define STXXL_FILEPERBLOCK_FILE_HEADER #include <string> #include <stxxl/bits/io/disk_queued_file.h> __STXXL_BEGIN_NAMESPACE //! \addtogroup fileimpl //! \{ //! \brief Implementation of file based on other files, dynamically allocate one file per block. //! Allows for dynamic disk space consumption. template <class base_file_type> class fileperblock_file : public disk_queued_file { private: std::string filename_prefix; int mode; unsigned_type current_size; bool lock_file_created; base_file_type lock_file; protected: //! \brief Constructs a file name for a given block. std::string filename_for_block(unsigned_type offset); public: //! \brief constructs file object //! \param filename_prefix filename prefix, numbering will be appended to it //! \param mode open mode, see \c file::open_modes //! \param disk disk(file) identifier fileperblock_file( const std::string & filename_prefix, int mode, int queue_id = DEFAULT_QUEUE, int allocator_id = NO_ALLOCATOR); virtual ~fileperblock_file(); virtual void serve(const request * req) throw (io_error); //! \brief Changes the size of the file //! \param new_size value of the new file size virtual void set_size(offset_type new_size) { current_size = new_size; } //! \brief Returns size of the file //! \return file size in length virtual offset_type size() { return current_size; } virtual void lock(); //! \brief Frees the specified region. //! Actually deletes the corresponding file if the whole thing is deleted. virtual void discard(offset_type offset, offset_type length); //! Rename the file corresponding to the offset such that it is out of reach for deleting. virtual void export_files(offset_type offset, offset_type length, std::string filename); const char * io_type() const; }; //! \} __STXXL_END_NAMESPACE #endif // !STXXL_FILEPERBLOCK_FILE_HEADER