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1
5 package org.h2.index;
6
7 import java.sql.SQLException  ;
8
9 import org.h2.engine.Session;
10 import org.h2.store.DataPage;
11 import org.h2.store.Record;
12 import org.h2.util.ObjectArray;
13 import org.h2.value.Value;
14
15
18 public class LinearHashBucket extends Record {
19 private LinearHashIndex index;
20 private int nextBucket;
21 private ObjectArray records;
22 private boolean writePos;
23
24 public LinearHashBucket(LinearHashIndex index, DataPage s) throws SQLException {
25 this.index = index;
26 writePos = s.readByte() == 'P';
27 nextBucket = s.readInt();
28 int len = s.readInt();
29 records = new ObjectArray();
30 for(int i=0; i<len; i++) {
31 LinearHashEntry entry = new LinearHashEntry();
32 if(!writePos) {
33 Value key = s.readValue();
34 entry.key = key;
35 }
36 entry.hash = s.readInt();
37 entry.value = s.readInt();
38 entry.home = index.getPos(entry.hash);
39 records.add(entry);
40 }
41 }
42
43 public LinearHashBucket(LinearHashIndex index) {
44 this.index = index;
45 this.records = new ObjectArray();
46 this.nextBucket = -1;
47 }
48
49 private void update(Session session) throws SQLException {
50 index.updateBucket(session, this);
51 }
52
53 void setNext(Session session, int nextBucket) throws SQLException {
54 this.nextBucket = nextBucket;
55 update(session);
56 }
57
58 int getNextBucket() {
59 return nextBucket;
60 }
61
62 LinearHashEntry getRecord(int i) {
63 return (LinearHashEntry)records.get(i);
64 }
65
66 void addRecord(Session session, LinearHashEntry r) throws SQLException {
67 records.add(r);
68 update(session);
69 }
70
71 void removeRecord(Session session, int i) throws SQLException {
72 records.remove(i);
73 update(session);
74 }
75
76 int getRecordSize() {
77 return records.size();
78 }
79
80 public void write(DataPage buff) throws SQLException {
81 getRealByteCount(buff);
82 buff.writeByte((byte)'B');
83 if(writePos) {
84 buff.writeByte((byte)'P');
85 } else {
86 buff.writeByte((byte)'D');
87 }
88 buff.writeInt(nextBucket);
89 buff.writeInt(records.size());
90 for(int i=0; i<records.size(); i++) {
91 LinearHashEntry record = (LinearHashEntry) records.get(i);
92 if(!writePos) {
94 buff.writeValue(record.key);
95 }
96 buff.writeInt(record.hash);
97 buff.writeInt(record.value);
98 }
99 }
100
101 public int getByteCount(DataPage dummy) throws SQLException {
102 return index.getBucketSize();
103 }
104
105 public int getRealByteCount(DataPage dummy) throws SQLException {
106 int size = 2 + dummy.getIntLen() + dummy.getIntLen();
107 int datasize = 0;
108 for(int i=0; i<records.size(); i++) {
109 LinearHashEntry record = (LinearHashEntry) records.get(i);
110 datasize += dummy.getValueLen(record.key);
112 size += 2 * dummy.getIntLen();
113 }
114 if(size + datasize >= index.getBucketSize()) {
115 writePos = true;
116 return size;
117 } else {
118 writePos = false;
119 return size + datasize;
120 }
121 }
122
123 public boolean isEmpty() {
124 return false;
125 }
126
127 }
128 |
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