1 : /******************************************************************************
2 : *
3 : * Purpose: Declaration of the SysVirtualFile class.
4 : *
5 : * This class is used to manage access to a single virtual file stored in
6 : * SysBData segments based on a block map stored in the SysBMDir segment
7 : * (and managed by SysBlockMap class).
8 : *
9 : * The virtual files are allocated in 8K chunks (block_size) in segments.
10 : * To minimize IO requests, other overhead, we keep one such 8K block in
11 : * our working cache for the virtual file stream.
12 : *
13 : * This class is primarily used by the CTiledChannel class for access to
14 : * tiled images.
15 : *
16 : ******************************************************************************
17 : * Copyright (c) 2009
18 : * PCI Geomatics, 50 West Wilmot Street, Richmond Hill, Ont, Canada
19 : *
20 : * Permission is hereby granted, free of charge, to any person obtaining a
21 : * copy of this software and associated documentation files (the "Software"),
22 : * to deal in the Software without restriction, including without limitation
23 : * the rights to use, copy, modify, merge, publish, distribute, sublicense,
24 : * and/or sell copies of the Software, and to permit persons to whom the
25 : * Software is furnished to do so, subject to the following conditions:
26 : *
27 : * The above copyright notice and this permission notice shall be included
28 : * in all copies or substantial portions of the Software.
29 : *
30 : * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
31 : * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
32 : * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
33 : * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
34 : * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
35 : * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
36 : * DEALINGS IN THE SOFTWARE.
37 : ****************************************************************************/
38 : #ifndef __INCLUDE_CORE_SYSVIRTUALFILE_H
39 : #define __INCLUDE_CORE_SYSVIRTUALFILE_H
40 :
41 : #include "pcidsk_buffer.h"
42 :
43 : #include <vector>
44 :
45 : #define SYSVIRTUALFILE_BLOCKSIZE 8192
46 :
47 : namespace PCIDSK
48 : {
49 : class CPCIDSKFile;
50 : class SysBlockMap;
51 : /************************************************************************/
52 : /* SysVirtualFile */
53 : /************************************************************************/
54 :
55 : class SysVirtualFile
56 : {
57 : public:
58 : SysVirtualFile( CPCIDSKFile *file, int start_block, uint64 image_length,
59 : PCIDSKBuffer &block_map_data, SysBlockMap *sysblockmap,
60 : int image_index );
61 : ~SysVirtualFile();
62 :
63 : void Synchronize();
64 :
65 : void WriteToFile( const void *buffer, uint64 offset, uint64 size );
66 : void ReadFromFile( void *buffer, uint64 offset, uint64 size );
67 :
68 0 : uint64 GetLength() { return file_length; }
69 :
70 : static const int block_size;
71 :
72 : private:
73 : CPCIDSKFile *file;
74 : SysBlockMap *sysblockmap;
75 : int image_index;
76 :
77 : uint64 file_length;
78 :
79 : std::vector<int> block_segment;
80 : std::vector<int> block_index;
81 :
82 : int loaded_block;
83 : uint8 block_data[SYSVIRTUALFILE_BLOCKSIZE];
84 : bool loaded_block_dirty;
85 :
86 : int last_bm_index;
87 :
88 : void LoadBlock( int requested_block );
89 : void LoadBlocks( int requested_block_start,
90 : int requested_block_count, void* const buffer);
91 : void GrowVirtualFile(std::ptrdiff_t requested_block);
92 : void FlushDirtyBlock();
93 : void WriteBlocks(int first_block, int block_count,
94 : void* const buffer);
95 : };
96 : }
97 :
98 : #endif // __INCLUDE_CORE_SYSVIRTUALFILE_H
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