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/******************************************************************************
*
* Purpose: Declaration of the SysVirtualFile class.
*
* This class is used to manage access to a single virtual file stored in
* SysBData segments based on a block map stored in the SysBMDir segment
* (and managed by SysBlockMap class).
*
* The virtual files are allocated in 8K chunks (block_size) in segments.
* To minimize IO requests, other overhead, we keep one such 8K block in
* our working cache for the virtual file stream.
*
* This class is primarily used by the CTiledChannel class for access to
* tiled images.
*
******************************************************************************
* Copyright (c) 2009
* PCI Geomatics, 50 West Wilmot Street, Richmond Hill, Ont, Canada
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
****************************************************************************/
#ifndef __INCLUDE_CORE_SYSVIRTUALFILE_H
#define __INCLUDE_CORE_SYSVIRTUALFILE_H
#include "pcidsk_buffer.h"
#include "pcidsk_mutex.h"
#include <vector>
#define SYSVIRTUALFILE_BLOCKSIZE 8192
namespace PCIDSK
{
class CPCIDSKFile;
class SysBlockMap;
/************************************************************************/
/* SysVirtualFile */
/************************************************************************/
class SysVirtualFile
{
public:
SysVirtualFile( CPCIDSKFile *file, int start_block, uint64 image_length,
SysBlockMap *sysblockmap, int image_index );
~SysVirtualFile();
void Synchronize();
void WriteToFile( const void *buffer, uint64 offset, uint64 size );
void ReadFromFile( void *buffer, uint64 offset, uint64 size );
uint64 GetLength() { return file_length; }
static const int block_size;
private:
CPCIDSKFile *file;
void **io_handle;
Mutex **io_mutex;
SysBlockMap *sysblockmap;
int image_index;
uint64 file_length;
bool regular_blocks;
int blocks_loaded;
std::vector<uint16> xblock_segment;
std::vector<int> xblock_index;
int next_bm_entry_to_load;
int loaded_block;
uint8 block_data[SYSVIRTUALFILE_BLOCKSIZE];
bool loaded_block_dirty;
int last_bm_index;
uint16 GetBlockSegment( int requested_block );
int GetBlockIndexInSegment( int requested_block );
void SetBlockInfo( int requested_block,
uint16 new_block_segment,
int new_block_index );
void LoadBlock( int requested_block );
void LoadBlocks( int requested_block_start,
int requested_block_count,
void* const buffer);
void GrowVirtualFile(std::ptrdiff_t requested_block);
void FlushDirtyBlock();
void WriteBlocks(int first_block, int block_count,
void* const buffer);
void LoadBMEntrysTo( int block_index );
};
}
#endif // __INCLUDE_CORE_SYSVIRTUALFILE_H
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