mirror of
https://github.com/FirebirdSQL/firebird.git
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121 lines
4.0 KiB
C++
121 lines
4.0 KiB
C++
/*
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* PROGRAM: JRD Access Method
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* MODULE: btn.h
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* DESCRIPTION: B-tree management code
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*
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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 Arno Brinkman
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* for the Firebird Open Source RDBMS project.
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*
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* Copyright (c) 2003 Arno Brinkman and all contributors
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* 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 JRD_BTN_H
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#define JRD_BTN_H
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#include "firebird.h" // needed for get_long
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#include "memory_routines.h" // needed for get_long
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#include "../jrd/common.h"
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#include "../jrd/ods.h"
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#include "../common/classes/array.h"
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// format of expanded index node, used for backwards navigation
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struct btree_exp
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{
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UCHAR btx_previous_length; // AB: total size for previous node --length of data for previous node
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UCHAR btx_btr_previous_length; // length of data for previous node on btree page
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UCHAR btx_data[1]; // expanded data element
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};
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const int BTX_SIZE = 2;
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// Flags (3-bits) used for index node
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const int BTN_NORMAL_FLAG = 0;
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const int BTN_END_LEVEL_FLAG = 1;
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const int BTN_END_BUCKET_FLAG = 2;
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const int BTN_ZERO_PREFIX_ZERO_LENGTH_FLAG = 3;
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const int BTN_ZERO_LENGTH_FLAG = 4;
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const int BTN_ONE_LENGTH_FLAG = 5;
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//const int BTN_ZERO_PREFIX_ONE_LENGTH_FLAG = 6;
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//const int BTN_GET_MORE_FLAGS = 7;
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// format of expanded index buffer
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struct exp_index_buf
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{
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USHORT exp_length;
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ULONG exp_incarnation;
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btree_exp exp_nodes[1];
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};
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const size_t EXP_SIZE = OFFSETA (exp_index_buf*, exp_nodes);
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struct dynKey
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{
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USHORT keyLength;
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UCHAR* keyData;
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};
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typedef Firebird::Array<dynKey*> keyList;
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typedef Firebird::HalfStaticArray<Ods::IndexJumpNode, 32> jumpNodeList;
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namespace BTreeNode {
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USHORT computePrefix(const UCHAR* prevString, USHORT prevLength,
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const UCHAR* string, USHORT length);
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SLONG findPageInDuplicates(const Ods::btree_page* page, UCHAR* pointer,
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SLONG previousNumber, RecordNumber findRecordNumber);
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USHORT getJumpNodeSize(const Ods::IndexJumpNode* jumpNode, UCHAR flags);
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USHORT getNodeSize(const Ods::IndexNode* indexNode, UCHAR flags, bool leafNode = true);
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UCHAR* getPointerFirstNode(Ods::btree_page* page, Ods::IndexJumpInfo* jumpInfo = NULL);
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bool keyEquality(USHORT length, const UCHAR* data, const Ods::IndexNode* indexNode);
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#ifdef SCROLLABLE_CURSORS
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UCHAR* lastNode(btree_page* page, exp_index_buf* expanded_page, btree_exp** expanded_node);
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#endif
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UCHAR* nextNode(Ods::IndexNode* node, UCHAR* pointer,
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UCHAR flags, btree_exp** expanded_node);
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UCHAR* previousNode(Ods::IndexNode* node, UCHAR* pointer,
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UCHAR flags, btree_exp** expanded_node);
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//void quad_put(SLONG value, UCHAR *data);
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UCHAR* readJumpInfo(Ods::IndexJumpInfo* jumpInfo, UCHAR* pagePointer);
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UCHAR* readJumpNode(Ods::IndexJumpNode* jumpNode, UCHAR* pagePointer, UCHAR flags);
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UCHAR* readNode(Ods::IndexNode* indexNode, UCHAR* pagePointer, UCHAR flags,
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bool leafNode);
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UCHAR* writeJumpInfo(Ods::btree_page* page, const Ods::IndexJumpInfo* jumpInfo);
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UCHAR* writeJumpNode(Ods::IndexJumpNode* jumpNode, UCHAR* pagePointer, UCHAR flags);
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UCHAR* writeNode(Ods::IndexNode* indexNode, UCHAR* pagePointer, UCHAR flags,
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bool leafNode, bool withData = true);
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void setEndBucket(Ods::IndexNode* indexNode, bool leafNode = true);
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void setEndLevel(Ods::IndexNode* indexNode, bool leafNode = true);
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void setNode(Ods::IndexNode* indexNode, USHORT prefix = 0, USHORT length = 0,
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RecordNumber recordNumber = RecordNumber(0), SLONG pageNumber = 0,
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bool isEndBucket = false, bool isEndLevel = false);
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} // namespace BTreeNode
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#endif // JRD_BTN_H
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