mirror of
https://github.com/FirebirdSQL/firebird.git
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308 lines
9.1 KiB
C++
308 lines
9.1 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(Ods::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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inline 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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inline UCHAR* BTreeNode::readNode(Ods::IndexNode* indexNode, UCHAR* pagePointer, UCHAR flags, bool leafNode)
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{
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/**************************************
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*
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* r e a d N o d e
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*
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**************************************
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*
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* Functional description
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* Read a leaf/page node from the page by the
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* given pagePointer and the return the
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* remaining position after the read.
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*
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**************************************/
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indexNode->nodePointer = pagePointer;
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if (flags & Ods::btr_large_keys) {
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// Get first byte that contains internal flags and 6 bits from number
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UCHAR* localPointer = pagePointer;
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UCHAR internalFlags = *localPointer++;
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SINT64 number = (internalFlags & 0x1F);
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internalFlags = ((internalFlags & 0xE0) >> 5);
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indexNode->isEndLevel = (internalFlags == BTN_END_LEVEL_FLAG);
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indexNode->isEndBucket = (internalFlags == BTN_END_BUCKET_FLAG);
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// If this is a END_LEVEL marker then we're done
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if (indexNode->isEndLevel) {
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indexNode->prefix = 0;
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indexNode->length = 0;
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indexNode->recordNumber.setValue(0);
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indexNode->pageNumber = 0;
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return localPointer;
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}
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// Get remaining bits for number
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ULONG tmp = *localPointer++;
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number |= (tmp & 0x7F) << 5;
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if (tmp >= 128) {
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tmp = *localPointer++;
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number |= (tmp & 0x7F) << 12;
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if (tmp >= 128) {
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tmp = *localPointer++;
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number |= (tmp & 0x7F) << 19;
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if (tmp >= 128) {
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tmp = *localPointer++;
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number |= (FB_UINT64) (tmp & 0x7F) << 26;
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if (tmp >= 128) {
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tmp = *localPointer++;
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number |= (FB_UINT64) (tmp & 0x7F) << 33;
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/*
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Uncomment this if you need more bits in record number
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if (tmp >= 128) {
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tmp = *localPointer++;
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number |= (FB_UINT64) (tmp & 0x7F) << 40;
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if (tmp >= 128) {
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tmp = *localPointer++;
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number |= (FB_UINT64) (tmp & 0x7F) << 47;
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if (tmp >= 128) {
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tmp = *localPointer++;
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number |= (FB_UINT64) (tmp & 0x7F) << 54; // We get 61 bits at this point!
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}
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}
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}
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*/
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}
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}
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}
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}
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indexNode->recordNumber.setValue(number);
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if (!leafNode) {
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// Get page number for non-leaf pages
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tmp = *localPointer++;
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number = (tmp & 0x7F);
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if (tmp >= 128) {
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tmp = *localPointer++;
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number |= (tmp & 0x7F) << 7;
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if (tmp >= 128) {
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tmp = *localPointer++;
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number |= (tmp & 0x7F) << 14;
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if (tmp >= 128) {
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tmp = *localPointer++;
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number |= (tmp & 0x7F) << 21;
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if (tmp >= 128) {
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tmp = *localPointer++;
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number |= (tmp & 0x0F) << 28;
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/*
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Change number to 64-bit type and enable this for 64-bit support
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number |= (*tmp & 0x7F) << 28;
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if (tmp >= 128) {
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tmp = *localPointer++;
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number |= (*tmp & 0x7F) << 35;
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if (tmp >= 128) {
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tmp = *localPointer++;
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number |= (*tmp & 0x7F) << 42;
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if (tmp >= 128) {
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tmp = *localPointer++;
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number |= (*tmp & 0x7F) << 49;
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if (tmp >= 128) {
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tmp = *localPointer++;
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number |= (*tmp & 0x7F) << 56; // We get 63 bits at this point!
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}
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}
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}
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}
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*/
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}
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}
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}
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}
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indexNode->pageNumber = number;
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}
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if (internalFlags == BTN_ZERO_PREFIX_ZERO_LENGTH_FLAG) {
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// Prefix is zero
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indexNode->prefix = 0;
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}
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else {
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// Get prefix
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tmp = *localPointer++;
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indexNode->prefix = (tmp & 0x7F);
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if (tmp & 0x80) {
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tmp = *localPointer++;
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indexNode->prefix |= (tmp & 0x7F) << 7; // We get 14 bits at this point
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}
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}
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if ((internalFlags == BTN_ZERO_LENGTH_FLAG) ||
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(internalFlags == BTN_ZERO_PREFIX_ZERO_LENGTH_FLAG))
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{
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// Length is zero
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indexNode->length = 0;
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}
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else if (internalFlags == BTN_ONE_LENGTH_FLAG) {
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// Length is one
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indexNode->length = 1;
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}
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else {
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// Get length
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tmp = *localPointer++;
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indexNode->length = (tmp & 0x7F);
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if (tmp & 0x80) {
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tmp = *localPointer++;
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indexNode->length |= (tmp & 0x7F) << 7; // We get 14 bits at this point
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}
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}
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// Get pointer where data starts
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indexNode->data = localPointer;
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localPointer += indexNode->length;
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return localPointer;
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}
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else {
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indexNode->prefix = *pagePointer++;
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indexNode->length = *pagePointer++;
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if (leafNode) {
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// Nice sign extension should happen here
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indexNode->recordNumber.setValue(get_long(pagePointer));
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indexNode->isEndLevel = (indexNode->recordNumber.getValue() == Ods::END_LEVEL);
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indexNode->isEndBucket = (indexNode->recordNumber.getValue() == Ods::END_BUCKET);
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}
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else {
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indexNode->pageNumber = get_long(pagePointer);
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indexNode->isEndLevel = (indexNode->pageNumber == Ods::END_LEVEL);
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indexNode->isEndBucket = (indexNode->pageNumber == Ods::END_BUCKET);
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}
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pagePointer += sizeof(SLONG);
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indexNode->data = pagePointer;
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pagePointer += indexNode->length;
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// Get recordnumber for non-leaf-nodes and on leaf-nodes when
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// last node is END_BUCKET and duplicate (or NULL).
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if ((flags & Ods::btr_all_record_number) &&
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((!leafNode) ||
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(leafNode && indexNode->isEndBucket && (indexNode->length == 0))))
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{
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indexNode->recordNumber.setValue(get_long(pagePointer));
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pagePointer += sizeof(SLONG);
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}
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}
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return pagePointer;
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}
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#endif // JRD_BTN_H
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