mirror of
https://github.com/FirebirdSQL/firebird.git
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125 lines
2.9 KiB
C++
125 lines
2.9 KiB
C++
/*
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* The contents of this file are subject to the Initial
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* Developer's Public License Version 1.0 (the "License");
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* you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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* http://www.ibphoenix.com/main.nfs?a=ibphoenix&page=ibp_idpl.
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*
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* Software distributed under the License is distributed AS IS,
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* WITHOUT WARRANTY OF ANY KIND, either express or implied.
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* See the License for the specific language governing rights
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* and limitations under the License.
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*
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* The Original Code was created by Dmitry Yemanov
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* for the Firebird Open Source RDBMS project.
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*
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* Copyright (c) 2002 Dmitry Yemanov <dimitr@users.sf.net>
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* and all contributors signed below.
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*
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* All Rights Reserved.
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* Contributor(s): ______________________________________.
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*/
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#ifndef SORT_MEM_H
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#define SORT_MEM_H
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#include "../jrd/sort.h"
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/*
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* Virtual scratch file
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*/
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class SortMem {
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private:
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// Generic storage block
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class Block {
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friend class SortMem;
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protected:
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Block *prev;
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Block *next;
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size_t size;
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public:
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// Read bytes from the block into the given buffer
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virtual size_t read(ISC_STATUS*, size_t, char*, size_t) = 0;
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// Write bytes from the given buffer into the block
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virtual size_t write(ISC_STATUS*, size_t, char*, size_t) = 0;
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Block(Block*, size_t);
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virtual ~Block() {}
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};
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// Virtual memory block
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class MemoryBlock : public Block {
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private:
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// Base address of the allocated virtual memory
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char* address;
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public:
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size_t read(ISC_STATUS*, size_t, char*, size_t);
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size_t write(ISC_STATUS*, size_t, char*, size_t);
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MemoryBlock(Block*, size_t);
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~MemoryBlock();
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};
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// File block
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class FileBlock : public Block {
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private:
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// Sort file block
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struct sfb *file;
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// File offset
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size_t offset;
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public:
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size_t read(ISC_STATUS*, size_t, char*, size_t);
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size_t write(ISC_STATUS*, size_t, char*, size_t);
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FileBlock(Block*, size_t, struct sfb*, size_t);
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~FileBlock();
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};
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// Initialization flag
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static bool is_initialized;
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// Virtual memory allocation values
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static size_t mem_block_size;
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static size_t mem_upper_limit;
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// Total amount of allocated virtual memory
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static size_t mem_total_size;
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struct sfb *internal;
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// Virtual scratch file size
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size_t logical_size;
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// Amount of storage space allocated for this scratch file
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size_t physical_size;
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// File size on disk
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size_t file_size;
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// First block in chain
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Block *head;
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// Last block in chain
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Block *tail;
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// Allocate one more block, if necessary
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void allocate(size_t);
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// Convert logical position to the physical one - pair [block, offset]
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Block* seek(size_t&);
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public:
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// Read bytes from the scratch file
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size_t read(ISC_STATUS*, size_t, char*, size_t);
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// Write bytes into the scratch file
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size_t write(ISC_STATUS*, size_t, char*, size_t);
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SortMem(struct sfb*, size_t);
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~SortMem();
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};
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#endif // SORT_MEM_H
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